CA1082190A - Pyridazinone derivatives - Google Patents

Abstract

A B S T R A C T

Certain 6-(substituted phenyl)-3(2H)-pyridazinones and 6-(substituted phenyl)-4,5-dihydro-3(2H)-pyridazinones, in which the substituted phenyl group has a halogen atom at one or both of the 3- and 5- positions, are useful as agricultural fungicides.

Description

108~190 The present invention relates to an agricultural fungicidal composition, in which the active ingredient is a 6-(substituted phenyl)-3(2H)-pyridazinone or a 6-(substituted phenyl)-4,5-dihydro-3(2H)-pyridazinone, and also to a certain group of new pyridazinone derivatives.

Although very many different types of compound are known for use as fungicides in the field of agricultural chemicals, there is a continuous demand from the users for new agricultural fungicides.

We have now unexpectedly found that certain pyridazinone ; derivatives have very prominent fungicidal activity.
, , Thus, according to one feature of the present invention, there is provided a fungicidal composition comprising a pyridazinone derivative of general formula (I): i . I . .
.:, , R2 a1 A
a3 ~\N ~>= Il) n~ H
' : . : . , I .

~ n which:
Rl represents a hydrogen atom, a hydroxy group~ a group of formula -o-Co-R5 (in which R5 represents an alkyl group having from 1 to 5 .:
$~

~ .... !

108~190 carbon atoms) or a group of formula -O-S02-R6 (in which R6 represents a phenyl group which is unsubstituted or has one or more halogen or C1 3 alkyl substituents);
R2 and R4 are the same or different and each represents a halogen atom, or one of R2 and R4 represents a halogen atom and the other represents a hydrogen atom;
R3 represents a hydrogen atom, an alkyl group having from 1 to 6 carbon atoms, an alkoxy group having from 1 to 6 carbon atoms, an alkenyloxy ¦ ;
group having from 3 to 5 carbon atoms, an alkynyloxy group having 3 or 4 carbon atoms~ an amino group, a hydroxy group, a halogen atom, a group of formula -0-C0-R5 (in which R5 is as defined above) or a group of formula -O-S02-R6 (in which R6 is as defined above); and A represents the group -CH2-CH2- or -CH=CH-~
- or when A represents the group -CH=CH-, a salt thereof, and an agricul-turally acceptable carrier or diluent.
'' ' According to a further feature of the present invention~
there is provided a method for the control of pathogenic fungi in plants, seeds or soil~ which comprises applying to said plant, seed or soil a pyridazinone derivative having the formula (I) or a salt thereof, as defined above.

, loszlso ' ' According to a further feature of the present invention, there are provided new pyridazinone derivatives having the formula (II):

R ~--N N> I

.

~n which:
Rl, R3 and A are as defined above; and R7 and R8 are the same or different and each represents a halogen atom or one of R7 and R8 represents a halogen atom and the other represents a hydrogen atom, provided that, when R3 represents a halogen atom, a hydroxy group or said alkoxy group, both R7 and R8 represent halogen atom~ and~ vhen A represents the group -CH=CH-~ salts thereof.

Certain of the pyridazinone derivatives of general formula (I) are known compounds and certain related pyridazinones are also known, as follows:

~082190 U.S. Patent Specification No. 2,624,730 discloses that the 6-(4-halophenyl)-3(2H)-pyridazinones and the 6-(3,4-dihalophenyl)-3(2H)-pyridazinones are useful as amoebicides.

J. Heterocyclic. Chem., 11, 755 (1974) discloses that 6-(4-chloro-3-methylphenyl)-3(2H)-pyridazinone, 6-(3-bromo-4-methoxy-` phenyl)-3(2H)-pyridazinone, 6-(4-chloro-3-nitrophenyl)-3(2H)-pyridazinone, 6-(4-methoxyphenyl)-3(2H)-pyridazinone, 6-(4-methoxyphenyl)-4,5-dihydro-3(2H)-pyridazinone and 6-(4-chloro-3-methylphenyl)-4,5-dihydro-3(2H)-; pyridazinone are useful as antiprotozoal agents.

. .
~; 10 French Patent Specification No. 1~507~475 discloses that 6-(4-aminophenyl)-4,5-dihydro-3(2H)-pyridazinone can be employed as an intermediate in the synthesis of medicines and dyestuffs.

', Japanese Patent Application No. 93984/75, as laid open to public inspection, discloses that 6-(3-chloro-4-hydroxyphenyl)-4,5-dihydro-3(2H)-pyridazinone is useful as an intermediate in the synthesis of medicines.

Japanese Patent Publication No. 12740/69 discloses that 6-(4-aminophenyl)-3(2H)-pyridazinone may be employed as an intermediate in the synthesis of dyestuffs.

.
- ~ ~

.: .

, Those pyridazinone derivatives of formula (I) wherein A represents the group -CH=CH- may be present in the form of the tautomerism as shown below:

R3~0 ~--R3~111 . 2 R3~D~

. !
, .
15 (wherein R1, R2, R3 and R4 are as defined above).

:` ' In the above formulae (I) and (II), where R2, R3 and R4 represent halogen atoms, they may be chlorine, bromine, fluorine or iodine atoms~ preferably chlorine, fluorine or bromine atoms.

Where R3 represents an alkyl group, it may be a straight or branched chain alkyl group having from 1 to 6 carbon atoms~ for example a methyl group, an ethyl group, a propyl group, an isopropyl .
.

group, a butyl group~ an isobutyl group, a sec-butyl group, a t-butyl group, an amyl group, an isoamyl group, a sec-amyl group or a hexyl group, preferably a methyl or ethyl group.

, Where R3 represents an alkoxy group, it may be a straight S or branched chain alkoxy group having from 1 to 6 carbon atoms, for example a methoxy group, an ethoxy group, a propoxy group, an isopropoxy group~ a butoxy group, an isobutoxy group, a sec-butoxy group, a t-butoxy -group, an amyloxy group, an isoamyloxy group~ a sec-amyloxy group or a hex~loxy group~ preferably a methoxy or ethoxy group.

l~here R1 or R3 represents the group -o-Co-R5, RS may be any of the alkyl groups exemplified above for R3, other than hexyl. l~here -1 or R3 represents the group -0-S02-R6, R6 may be, for example, a phenyl group, an o-chlorophenyl group~ a m-chlorophenyl group, a E~chlorophenyl group, a E~bromophenyl group, a 2,4-dichlorophenyl group, an o-tolyl group, a m-tolyl group, a E-tolyl group~ a 4-ethylphenyl group or a 2-propylphenyl group~ preferably a p tolyl group.
:' ' Where R3 represents an alkenyloxy group~ it may be~ for example, ~ an allyloxy group~a 2-butenyloxy group~ a 1-methyl-2-propenyloxy group~ a -~ 2-nethyl-2-propenyloxy group~ a 3-butenyloxy group or a 2-pentenyloxy group, preferably an alkenyloxy group having 3 or 4 carbon atoms.

, , ,, . - ~

1082190 !~
I
. , Where R3 represents an alkynyloxy group~ it may be, for example, a 2-propynyloxy group, a 1-methyl-2-propynyloxy group, a

2-butynyloxy group or a 3-butynyloxy group, preferably a 2-propynyloxy group.

~ . .
Preferred classes of compound falling within formula (I) and/or (II) are as follows:

GROUP A
Those compounds wherein R1 represents a hydrogen atom or a hydroxy group, particularly a hydrogen atom; R2 and R4 are the-same - 10 or different and each represents a halogen atom, particularly a chlorine, fluorine or bromine atom; and-R3 represents a hydrogen atom, an amino group, a methyl or ethyl group (particularly a methyl group), a methoxy ,i .
or ethoxy group (particularly a methoxy group), or an alkenyloxy group having 3 or 4 carbon atoms (particularly an allyloxy group).
.~
.~
i 15 GRO~P B

Those compounds wherein R1 and R4 each represent hydrogen atoms; and R2 and R3 are the same or different and each represents a ' chlorine, fluorine or bromine atom~ or R2 represents a chlorine or - bromine atom and R3 represents a hydrogen atom, a methyl group or an ethyl group.

: ~ :

.
.

, . ' ' . ' ' . - . .

1o82l9o . GROUP C
I
Those compounds wherein R1 represents a hydrogen atom or a hydroxy group; R2 and R4 are the same or different and each represents a halogen atom, or one of R2 and R4 represents a halogen 1 5 atom and the other represents a hydrogen atom; R3 represents a hydrogen atom, an alkyl group having from 1 to 6 carbon atoms, an alkoxy group having from 1 to 6 carbon atoms, an ~m;no group, a hydroxy group or a halogen atom; and A represents the group -CH=CH-. ¦ 3 GROUP Ct .
IO Those compounds wherein: Rl represents a hydrogen atom or a hydroxy group; R2 and R4 are the same or different and each - represents a halogen atom or one of R2 and R4 represents a halogen atom and the other represents a hydrogen atom; R3 represents an alkyl group having from 1 to 6 carbon atoms, a hydroxy group or a halogen atom; and A represents the group -CH=CH-.
, ~.
. Salts of compounds falling within Groups A, B, C and C~ are also preferred.

Particularly preferred compounds are those in which: Rl represents a hydrogen atom; R2 and R4 are the same or different and each represents a chlorine, fluorine or bromine atom; and R3 represents a methyl, ethyl, methoxy or ethoxy group.

., .: . .
.

1082~90 Salts can be formed with compounds of formulae (I) and (II) only when A represents the group -CH=CH-. Such salts may be: acid addition salts, particularly salts with a m;neral acid, e.g. hydrochloric acid, sulphuric acid, hydrobromic acid or phosphoric acid; adducts with alkyl isocyanates, for example methyl isocyanate; alkali metal salts, ,.! for example the sodium, potassium or lithium salt; alkaline earth metal salts, for example the calcium or magnesium salt; salts with other mono-valent~ divalent or trivalent metal ions, e.g. with an aluminium or copper ion; and salts with complex ions.

The following is a list of representative examples of the pyridazinone derivatives of formula (I). The numbers appended to the ~t~ compounds in this list are used hereinafter to identify the compounds.

, :' ' ' _ g _ 1o8219 1. 6-(3,4-dichlorophenyl)-3(2H)-pyridazinone 2. 6-(3,4,5~trichlorophenyl)-3(2H)-pyridazinone

3. 6-(5-bromo-3,4-dichlorophenyl)-3(2H)-pyridazinone

4. 6-(3-chloro-4-methylphenyl)-3(2H)-pyridazinone

5. 6-(3-bromo-4-methylphenyl)-3(ZH)-pyridazinone

6. 6-(3-chloro-4-isopropylphenyl)-3(2H)-pyridazinone

7. 6-(3,5-dichloro-4-methylphenyl)-3(2H)-pyridazinone -

8. 6-(3,5-dibromo-4-methylphenyl)-3(2H)-pyridazinone

9. 6-(3,5-diiodo-4-methylphenyl)-3(2H)-pyridazinone

10. 6-(3,5-dichloro-4-ethylphenyl)-3(2H)-pyridazinone

11. 6-(3,5-dibromo-4-ethylphenyl)-3(2H)-pyridazinone

12. 6-(3,5-dichloro-4-propylphenyl)-3(2H)-pyridazinone

13. 6-(3,5-dibromo-4-propylphenyl)-3(2H)-pyridazinone

14. 6-(4-butyl-3,5-dichlorophenyl)-3(2H)-pyridazinone

15. 6-(3,5-dichloro-4-sec-butylphenyl)-3(2H)-pyridazinone

16. 6-(3,5-dichloro-4-t-butylphenyl)-3(ZH)-pyridazinone . .

17. 6-(3~5-dichloro-5-pentylphenyl)-3(2H)-pyridazinone

18. 6-(3,5-dichloro-4-sec-amylphenyl)-3(2H)-pyridazinone

19. 6-(3,5-dichloro-4-hexylphenyl)-3(2H)-pyridazinone

20. 6-(3,5-dibromo-4-chloro-2-hydroxyphenyl)-3(2H)-pyridazinone

21. 6-(3,5-dibromo-2-hydroxy-4-~ethylphenyl)-3(2H)-pyridazinone

22. 6-(3~5-dichloro-2-hydroxy-4-methylphenyl)-3(2H)-pyridazinone

23. 6-(3~5-dibromo-4-ethyl-2-hydroxyphenyl)-3(2H)-pyridazinone

24. 6-(3,5-dibromo-2-hydroxy-4-t-butylphenyl)-3(2H)-pyridazinone

25. 6-(5-chloro-2-hydroxy-4-methylphenyl)-3(2H)-pyridazinone

26. 6-(3,5-dichloro-4-hydroxypheny~-3(2H)-pyridazinone

27. 6-(3,5-dibromo-4-hydroxyphenyl)-3(2H)-pyridazinone

28. 6-(3-bromo-5-chloro-2-hydroxy-4-methylphenyl)-3(2H)-pyridazinone

29. 6-(3-chloro-4-ethylphenyl)-3(2H)-pyridazinone

30. 6-(3-bromo-5-chloro-4-methylphenyl)-3(2H)-pyridazinone

31. 6-(3-bromophenyl)-3(2H)-pyridazinone

32. 6-(3-chlorophenyl)-3(2H)-pyridazinone

33. 6-(3-chloro-4-methoxyphenyl)-3(2H)-pyridazinone -

34. 6-(3,5-dichloro-4-methoxyphenyl)-3(2H)-pyridazinone

35. 6-(4-amino-3-chlorophenyl)-3(2H)-pyridazinone 6-(4-amino-3-bromophenyl)-3(2H)-pyridazinone 37. 6-(4-amino-3,5-dibromophenyl)-3(2H)-pyridazinone 38. 6-(3~5-dibromophenyl)-3(2H)-pyridazinone 39. 6-(3-bromo-5-chloro-2-hydroxyphenyl)-3(2H)-pyridazinone 40. 6-(3~5-dichloro-2-hydroxy-4-methoxyphenyl)-3(2H)-pyridazinone 41. 6-(3,5-dibromo-4-ethoxyphenyl)-3(2H)-pyridazinone 42. 6-(5-chloro-2-hydroxyphenyl)-3(2H)-pyridazinone 43. 6-(3,5-dichloro-2-hydroxyphenyl)-3(2H)-pyridazinone 44. 6-(4-Am;no-3~5-dichlorophenyl)-3(2H)-pyridazirone 45. 6-(3,5-dichloro-4-ethoxyphenyl)-3(2H)-pyridazinone 46. 6-(3,5-dibromo-4-methoxyphenyl)-3(2H)-pyridazinone 47. 6-(4-~;no-5-bromo-3-chlorophenyl)-3(2H)-pyridazinone 48. 6-(5-bromo-3-chloro-4-methoxyphenyl)-3(2H)-pyridazinone 49. 6-(5-bromo-3-chloro-4-ethoxyphenyl)-3(2H)-pyridazinone 50. ~-(3~5-diiodo-4-hydroxyphenyl)-3(2H)-pyridazinone .

l~szlso 6-(4-bromo-3-chlorophenyl)-3(ZH)-pyridazinone 52. 6-(3,5-dichloro-4-isopropylphenyl)-3(2H)-pyridazinone 53. 6-(3~5-dibromo-4-isopropylphenyl)-3(2H)-pyridazinone 54. 6-(3-chloro-2-hydroxyphenyl)-3(2H)-pyridazinone 55. 6-(3-chloro-2-hydroxy-4-methylphenyl)-3(2H)-pyridazinone 56. 6-(3,5-dichloro-2,4-dihydroxyphenyl)-3(2H)-pyridazinone 57. 6-(3,4-dichloro-2-hydroxyphenyl)-3(2H)-pyridazinone 58. 6-(5-chloro-2-hydroxy-4-methoxyphenyl)-3(2H)-pyridazinone 59. 6-(5-bromo-2,4-dihydroxyphenyl)-3(2H)-pyridazinone 60. 6-(4,5-dichloro-2-hydroxyphenyl)-3(2H)-pyridazinone 61. 6-(3,4-dibromophenyl)-3(2H)-pyridazinone 62. 6-(3-chloro-4-fluorophenyl)-3(2H)-pyridazinone 63. 6-(3-bromo-4-chlorophenyl)-3(2H)-pyridazinone 64. 6-(3-bromo-4-fluorophenyl)-3(2H)-pyridazinone 65. 6-(3-iodopheny~)-3(2H)-pyridazinone 66. 6-(3,4-dichlorophenyl)-3(2H)-pyridazinone methylisocyanate 67. 6-(3,5-dichloro-4-methylphenyl)-3(2H)-pyridazinone methyliso-cyanate 68. 6-(3-chloro-4-methylphenyl)-3(2H)-pyridazinone methylisocyanate 69. 6-(3-bromo-4-methylphenyl)-3(2H)-pyridazinone methylisocyanate 70. 6-(3-chlorophenyl)-3(2H)-pyridazinone hydrobromide . ............... . . . . . . . .

~08Z190 71. 6-(3-bromophenyl)-3(2H)-pyridazinone hydrobromide 72 6-(3~5-dichloro-4-hydroxyphenyl)-3(2H)-pyridazinone methyl-isocyanate 73~ 6-(3,5-dibromo-4-hexylphenyl)-3(2H)-pyridazinone 74. 6-(3,5-dichlorophenyl)-3(2H)-pyridazinone 75. 6-(4-allyloxy-3~5-dichlorophenyl)-3(2H)-pyridazinone 76. 6-~3,5-dichloro-4-(2-propynyloxy)phenyl~-3(ZH)-pyridazinone 77. 6-(4-bromo-3~5-dichlorophenyl)-3(2H)-pyridazinone 78. 6-(2-acetoxy-3~5-dibromo-4-methylphenyl)-3(2H)-pyridazinone 79. 6-(2-acetoxy-3-bromo-5-chloro-4-methylphenyl)-3(2H)-pyridazinone 80. 6-(2-acetoxy-3,5-dichloro-4-methylphenyl)-3(2H)-pyridazinone 81. 6-(3,5-dibromo-2-butyryloxy-4-methylphenyl)-3(2H)-pyridazinone 82. 6-(4-acetoxy-3,5-dichlorophenyl)-3(2H)-pyridazinone 83. 6-(3~5-dichloro-4-~toluenesulphonyloxyphenyl)-3(2H)-pyridazinone 84. 6-(3,5-dibromo-4-methyl-2-~toluenesulphonyloxyphenyl)-3( 2H)-pyridazinone 85. 6-(3,5-dibromo-2-P-chlorobenzenesulphonyloxy-4-methylphenyl)-3(2H)-pyridazinone 86. 6-(3-chloro-5-fluoro-4-methylphenyl)-3(2H)-pyridazinone 87. 6-(3~4-dichlorophenyl)-4,5-dihydro-3(2H)-pyridazinone 88. 6-(3,4~5-trichlorophenyl)-4,5-dihydro-3(2H)-pyridazinone 89. 6-(5-bromo-3,4-dichlorophenyl)-4,5-dihydro-3(2H)-pyridazinone 90. 6-(3-chloro-4-methylphenyl)-4,5-dihydro-3(2H)-pyridazinone 91 6-(3-bromo-4-methylphenyl)-4,5-dihydro-3(2H)-pyridazinone 92. 6-(3-chloro-4-isopropylphenyl)-4,5-dihydro-3(2H)-pyridazinone 93. 6-(3~5-dichloro-4-methylphenyl)-4~5-dihydro-3(2H)-pyridazinone !
94. 6-(3,5-dibromo-4-methylphenyl)-4,5-dihydro-3(2H)-pyridazinone ~
95. 6-(3~5-diiodo-4-methylphenyl)-4,5-dihydro-3(2H)-pyridazinone 96. 6-(3~5-dichloro-4-ethylphenyl)-4~5-dihydro-3(2H)-pyridazinone 97. 6-(3,5-dibromo-4-ethylphenyl)-4,5-dihydro-3(2H)-pyridazinone 98. 6-(3,5-dichloro-4-propylphenyl)-4,5-dihydro-3(2H)-pyridazinone -i 99. 6-(3~5-dibromo-4-propylphenyl)-4,5-dihydro-3(2H)-pyridazinone 100. 6-(4-butyl-3,5-dichlorophenyl)-4,5-dihydro-3(2H)-pyridazinone 101. 6-(3,5-dichloro-4-sec-butylphenyl)-4,5-dihydro-3(2H)-pyridazinone `~ 102. 6-(3~5-dichloro-4-t-butylphenyl)-4,5-dihydro-3(2H)-pyridazinone 103. 6-(3~5-dichloro-4-pentylphenyl)-4,5-dihydro-3(2H)-pyridazinone - 104. 6-(3,5-dichloro-4-sec-amylphenyl)-4,5-dihydro-3(2H)-pyridazinone 105. 6-(3,5-dichloro-4-hexylphenyl)-4,5-dihydro-3(2H)-pyridazinone ,~ , 106. 6-(3,5-dibromo-4-chloro-2-hydroxyphenyl)-4,5-dihydro-3(2H)-pyridazinone 107. 6-(3,5-dibromo-4-methyl-2-hydroxyphenyl)-4,5-dihydro-3(2H)-pyridazinone ~-108. 6-(3,5-dichloro-2-hydroxy-4-methylphenyl)-4,5-dihydro-3(2H)-pyridazinone ~ I , .. ", , l' 108Zl9~

109. 6-(3,5-dibromo-4-ethyl-2-hydroxyphenyl)-4,5-dihydro-3(2H)-pyridazinone 110. 6-(3,5-dibromo-2-hydroxy-4-t-butylphenyl)-4,5-dihydro-3(2H)-pyridazinone 111. 6-(5-chloro-2-hydro~-4-methylphenyl)-4,5-dihydro-3(2H)-pyridazinone :
112. 6-(3,5-dichloro-4-hydroxyphenyl)-4,5-dihydro-3(2H)-pyridazinone -113. 6-(3,5-dibromo-4-hydroxyphenyl)-4,5-dihydro-3(2H)-pyridazinone 114. 6-(3-bromo-5-chloro-2-hydroxy-4-methylphenyl~-4,5-dihydro-3(2H)-pyridazinone 115. 6-(3-chloro-4-ethylphenyl)-4,5-dihydro-3(2H)-pyridazinone 116. 6-(3-bromo-5-chloro-4-methylphenyl)-4,5-dihydro-3(2H)- i pyridazinone 117. 6-(3-bromophenyl)-4,5-dihydro-3(2H)-pyridazinone 118. 6-(3-chlorophenyl)-4,5-dihydro-3(2H)-pyridazinone 119. 6-(3-chloro-4~nethoxyphenyl)-4~5-dihydro-3(2H)-pyridazinone 120. 6-(3~5-dichloro-4~ethoxyphenyl)-4,5-dihydro-3(2H)-pyridazinone 121. 6-(4-amino-3-chlorophenyl)-4,5-dihydro-3(2H)-pyridazinone 122. 6-(4-amino-3-bromophenyl)-4,5-dihydro-3(2H)-pyridazinone 123. 6-(4-amino-3,5-dibromophenyl)-4,5-dihydro-3(2H)-pyridazinone 124. 6-(3~5-dibromophenyl)-4,5-dihydro-3(2H)-pyridazinone 125. 6-(3-bromo-5-chloro-2-hydrox~phenyl)-4,5-dihydro-3(2H)-pyridazinone -- 15 -- 1 .

,:

. .. - . . . . ...

126. 6-(3,5-dichloro-2-hydroxy-4-methoxyphenyl)-4,5-dihydro-3(2H)-pyridazinone 127. 6-(3,5-dibromo-4-ethoxyphenyl)-4,5-dihydro-3(2H)-pyridazinone 128. 6-(5-chloro-2-hydroxyphenyl)-4~5-dihydro-3(2H)-pyridazinone 129. 6-(3,5-dichloro-2-hydroxyphenyl)-4,5-dihydro-3(2H)-pyridazinone 130. 6-(4-amino-3,5-dichlorophenyl)-4,5-dihydro-3(2H)-pyridazinone 131. 6-(3~5-dichloro-4~ethoxyphenyl)-4~5-dihydro-3(2H)-pyridazinone 132. 6-(3,5-dibromo-4-methoxyphenyl)-4,5-dihydro-3(2H)-pyridazinone 133. 6-(4-amino-5-bromo-3-chlorophenyl)-4,5-dihydro-3(2H)-pyridazinone 134. 6-(5-bromo-3-chloro-4-methoxyphenyl~-4~5-dihydro-3(2H)-pyridazinone 135- 6-(5-bromo-3-chloro-4-ethoxyphenyl)-4,5-dihydro-3(2H)-pyridazinone ... .
136. 6-(4-hydroxy-3~5-diiodophenyl)-4,5-dihydro-3(2H)-pyridazinone 137- 6-(4-bromo-3-chlorophenyl)-4,5-dihydro-3(2H)-pyridazinone 138. 6-(3,5-dichloro-4-isopropylphenyl)-4,5-dihydro-3(2H)-pyridazinone 139. 6-(3-chloro-4-fluorophenyl)-4~5-dihydro-3(2H)-pyridazinone 140. 6-(3~5-dibromo-4-hexylphenyl)-4,5-dihydro-3(2H)-pyridazinone 3 141. 6-(3~5-dichloro-2~4-dihydroxyphenyl)-4~5-dihydro-3(2H)-pyridazinone 142. 6-(5-bromo-2,4-dihydroxyphenyl)-4,5-dihydro-3(2H)-pyridazinone 143. 6-(4,5-dichloro-2-hydroxyphenyl)-4~5-dihydro-3(2H)-pyridazinone 144. 6-(3,5-dichlorophenyl)-4,5-dihydro-3(2H)-pyridazinone 145- 6-(3-iodophenyl)-4~5-dihydro-3(2H)-pyridazi~one 146. 6-(4-allyloxy-3,5-dichlorophenyl)-4,5-dihydro-3(2H)-pyridazinone 147- 6-(3,5-dichloro-4-propoxyphenyl)-4,5-dihydro-3(2H)-pyridazinone .

- -.
.. . . .

148. 6-C3~5-dichloro-4-(2-propynyloxy)phenyl~-4~5-dihydro-3(2H)-pyridazinone 149. 6-(3,5-diiodo-4-methoxyphenyl)-4,5-dihydro-3(2H)-pyridazinone 150. 6-(3,5-dichloro-4-fluorophenyl)-4,5-dihydro-3(2H)-pyridazinone 151. 6-(2-acetoxy-3,5-dichloro-4-methylphenyl)-4~5-dihydro-3(2H)-pyridazinone 152. 6-(3,5-dichloro-4-~-toluenesulphonyloxyphenyl)-4,5-dihydro-3(2H)-pyridazinone 153. 6-(4-acetoxy-3,5-dichlorophenyl)-4,5-dihydro-3(2H)-pyridazinone 154. 6-(3,5-dibromo-4-methyl-2-E-toluenesulphonyloxyphenyl)-4,5-dihydro-3(2H)-pyridazinone 155. 6-(3-fluorophenyl)-4,5-dihydro-3(2H)-pyridazinone 156. 6-(3-fluoro 4-methoxyphenyl)-4,5-dihydro-3(2H)-pyridazinone 157. 6-(3~4-difluorophenyl)-4,5-dihydro-3(2H)-pyridazinone 158. 6-(3~4-dibromophenyl)-4,5-dihydro-3(2H)-pyridazinone 159. 6-(3-chloro-5-fluoro-4-methylphenyl)-4~5-dihydro-3(2H)-pyridazinone 160. 6-(3-bromo-4-chlorophenyl)-4~5-dihydro-3(2H)-pyridazinone 161. 6-(3-bromo-4-fluorophenyl)-4,5-dihydro-3(2H)-pyridazinone 162. 6~4-bromo-3~5-dichlorophenyl)-4~5-dihydro-3(2H)-pyridazinone ,:

108Zl90 . , Of the above-listed pyridazinone derivatives, a preferred group having particularly good fungicidal activity against pathogenic fungi of the class Rhizoctonia are Compounds Nos. 1~ 4, 5, 7, 8, 30, 31, 32, 34, 87, 117 and 120. A preferred group of these pyridazinone S derivatives which have particularly good activity against the sheath .
; blight of rice plants are Compounds Nos. 1, 2, 4, 5, 6, 7, 8, lo, 20, .
21, 28, 30, 34, 37, 61, 62, 63, 64, 66, 67, 68, 69 and 120, and the .
: most preferred group are Compounds Nos. 1, 7, 8, 30, 34 and 62.

Of the compounds listed above~ Compounds Nos. 1 and 87 are - 10 known, but the other compounds are new.
~ .
Compounds having the above formula (I) and/or (II) can be prepared, for example, by the following processes.

PROCESS I
The process is s~mcarised by the fo11Oving reactior. scheme:

~' ' ' ', ' . : `' ~08Z190 , ' .

R2 R1 . R2a R3~ R3 R~ R~a IV1-1 ) 1\11-2 S IC-l)lo~ o ~'lC~ o~ o '~ ' -R2 Rl . R2a R3~--0~ 3~~

0 . lV~ 1-2J
. k-3)l NH2~1H2 Ic ~3 J ~¦ NH21JH2 , ~ ! R2 Rl .R2a 1 :
3~>=o R3~o . 11V-l) I~Y-2) PJ~[-H2] Ib~alogenation R2 Rl ~ [-H2~ ,-" R3~o R~ N-N llJJ) -- 19 _ '' lO~ZlgO ~l (In the above formulae, R1, R2, R3 and R4 are as defined above, and R2a and R4a each represent hydrogen atoms or one of R2a and R4a represents a hydrogen atom and the other represents a halogen atom).

Referring to the reaction scheme above, in step (a), a pyridazinone derivative of formula (III) is prepared by dehydrogenation of a corresponding 6-(substituted phenyl)-4,5-dihydro-3(2H)-pyridazinone of formula (IV-1), for example by the method disclosed in J. Amer. Chem.
Soc., 75, 1117 (1953). This reaction can be carried out in the presence of a dehydrogenating agent, for example bromine, chlorine, nitric acid, sodium hypochlorite, sodium chlorate, selenium dioxide or sodium m-nitro-benzenesulphonate, most preferably bromine. The reaction is preferably effected in the presence of a solvent and there is no particular limitation on the nature of the solvent, provided that it does not participate in the reaction. Examples of suitable solvents are: orga~ic acids, such as acetic acid, propionic acid and butyric acid; alcohols, such as methanol, ethanol, propanol, isopropanol and butanol; cyclic ethers, such as dioxan and tetrahydrofuran; ketones, such as acetone or methyl ethyl ketone; or a mixture ôf one or more of the above solvents with water. 3 We particularly prefer to employ bromine as the dehydrogenating agent and acetic acid as the solvent. In this case, the reaction temperature is preferably at least 50& ~ more preferably about the reflux tempera-ture of the solvent. The reaction time will vary depending upon the reaction temperature and the nature of the reagents employed~ but it will usually be from 1 to 10 hours.

- 20 - .

108~190 If sodium m-nitrobenzenesulphonate is employed as the dehydrogenating agent, the reaction may conveniently be carried out as disclosed in Japanese Patent Publication No. 12740/69. In that case, the solvent is preferably water or a mixture of water and an alcohol (such as ethanol, isopropanol or butanol), and the reaction is preferably carried out in the presence of an inorganic base, such as sodium hydroxide or potassium hydroxide.

After completion of the dehydrogenation step (a), the desired product can be recovered from the reaction mixture by con-ventional means.

The pyridazinone derivatives of general formula (III) may also be prepared, as shown in step (b),by direct halogenation of a corresponding compound of formula (IV-2), which has a hydrogen atom located at one or both of the 3- and 5- positions of the benzene ring.
This reaction may be performed simply by heating the compounds of formula (IY-2) with a halogenating agent in an inert solvent, simultane-ously to dehydrogenate the dihydropyridazine nucleus and to halogenate the 3- and/or 5- position of the benzene ring! In particular~ this reaction can produce, starting from a compound of formula (n-2) in ; 20 which R1 is a hydroxy group and both R2a and R4a are hydrogen atoms, the corresponding compound of formula (III).
.- . ' , - . .
.

Examples of halogenating agents which may be employed in this reaction are chlorine, bromQne, iodine and iodine monochloride, preferably bromine or chlorine. The reaction solvent is preferably an organic acid (such as acetic acid, propionic acid or butyric acid) or a mixture thereof with water, acetic acid being preferred. The reaction temperature is not normally below 50C, the reflux temperature of the solvent employed being preferred. The reaction time will vary, depending upon the reaction temperature and the reagents employed but it ~~
is usually from 1 to 10 hours.

Compounds (IV-1) and (IV-2), which are the starting materials for steps (a) and (b) described above may be prepared by the following processes:
l' In step (c-1), a substituted benzoylpropionic acid of formula (V-1) or (V-2) is prepared by a Friedel-Crafts reaction between a sub-j 15 stituted benzene of formula (VI-1) or (VI-2), respectively, and succinic anhydride~ in the presence of a Lewis acid. This reaction may be conducted by the method described in ~Organic Reactions~, 5~ 229 (1949), edited by Roger Adams and published by Jobn Wiley ~ Sons Co. Limited. Examples of Lewis acids which may be employed in the reaction are aluminium chloride~
~0 ferric chloride~ titanium tetrachloride, zinc chloride and stannic chloride~
of which we particularly prefer aluminium chloride. The molar ratio of ~, :

substituted benzene (VI-1) or (VI-2) to Lewis acid is preferably from 1:1 to 1:4, a value within the range from 1:2 to 1:2.5 being most preferred. We particularly prefer to conduct this reaction in the presence of an inert organic solvent, for example: carbon disulphide;
a substituted aromatic hydrocarbon, such as nitrobenzene or dichloro-benzene; or a halogenated aliphatic hydrocarbon, such as dichloro-methane, dichloroethane or tetrachioroethane. The reaction may also be carried out in the absence of a solvent, by using a large excess of the substituted benzene (VI-1) or (VI-2).

It is also possible to prepare the substituted benzoylpropionic acid of formula (V-1) by reacting the substituted benzoylpropionic acid of formula (V-2) (which has a hydrogen atom at the 3- andjor 5- position of the benzene ring~ with a halogenating agent in the presence of a Lewis acid. This reaction may be effected by the method described in ~ -Arzneimittel Forschung, 24, 1360 (1974). ~xamples of suitable halogenating agents are chlorine~ bromine, iodine, io~ine monochloride~ sulphuryl chloride and sulph 9 1 bromide. Suitable Lewis acids and reaction solvents are those described above in connection with step (c-1). In this halogena-tion, step (c-2), for example a benzoylpropionic add of formula (V-2) in which both the 3- and 5- positions of the benzene ring are occupied by hydrogen atoms may first be chlorinated at the 3- position and then brominated at the 5- position. Alternativelyj it may first be brominated at the 3- position and then chlorinated at the 5- position.

.. . . . . .

1~82190 As shown in step (c-3), the substituted benzoylpropionic acid of formula (V-1) or (V-2) is then reacted with hydrazine to form the 6-(substituted phenyl)-4,5-dihydro-3(2H)-pyridazinone of formula (IV-l) or (IV-2). This process is preferably effected by the method S described in J. Amer. Chem. Soc., 75, 1117 (1953). The hydrazine for this reaction may be employed in the form of, for example, hydrazine hydrate, hydrazine hydrochloride or hydrazine sulphate. The reaction is preferably also carried out in the presence of a solvent and there '~
is no particular limitation on the nature of the solvent, provided that it does not interfere with the reaction. Suitable solvents are:
alcohols, such as methanol~ ethanol~ propanol, isopropanol and butanol;
-~ cyclic ethers, such as tetrahydrofuran and dioxan; organic acids, such as acetic acid and propionic acid; halogenated hydrocarbons, such as dichloromethane and dichloroethane; and water. We particularly prefer to use an alcohol. The reaction temperature may be room temperature or above, preferably about the reflux temperature of the solvent employed.
The reaction time will vary, depending upon the reaction temperature and the nature of the reagents employed; however~ the reaction time is generally from 0.5 to 10 hours.

; 20 In place of step (c-3) shown, the compounds of formula (IV-1) or (IV-2) may be prepared by esterification to a lower alkyl ester of the 3-substituted benzoylpropionic acid (V-1) or (V-2) or by conversion of these acids to a corresponding functional derivative (such as an amide~

- 24- ,.

"

,~ 1o82l9o for example an unsubstituted amide or a lower allcylamide) in a conventional manner, followed by reaction of the ester, amide or other functional derivative with the hydrazine as described above.

If desired, the resulting compound of formula (IV-I) or (IY-2) may be separated from the reaction mixture and purified by conventional means. Where the compound of formula (IV-l) or (IV-2) is not the desired final product, it may be directly converted to the desired compound of .
formula (III) by dehydrogenation, and/or halogenation, as in steps (a) and (b) described above~ without intermediate isolation.

PROCESS II
Compounds having an amino group at the 4- position of the benzene ring, namely those compounds having the formulae (IV-4), (IV-5), (III-3)-and (III-4) shown below ~ 11 of which fall within foregoing -~ general formula (I)~ , may be prepared as shown in the following reaction sche=e:

.
., .
.
' :' .: ,: : , , -..
- . : :

10821~0 0~ 0 R9CoNH~ --R9CONH~OH

IVI - 3J IV - 3 ) I ,. I .
De~cylation S ' NH2~3~oH
Halogenatlon IV- 5) NH2NH2 .

R9tOl~H~OH R9CoNH ~3~0 IV - ~) / ~ (IV-3) Oe~cylation / \
R2 ~Halogenatio /
~ NH2~0H /.
`, 15 ~,~' O' 0~/ hH2NH~
. Deaql~tion NH2~}0 I l lV-~ ) 1 [ H2]
R2~
'' NH2~0 R9CO~lH~o (IV- 5) H llll- 2) H

.~

:' .

. .

108Z~90 IIV-5) 11~) Im-2) \I-H2]
\ ~Deacylation NH2~0 \\!-H2] /lm_~) H
\ ~ /H~logenation NH2~0 R UII-LI

.: :

":
~ ~
.
.~
-.
~
:, .

.. . . . . . . .

~1082190 (In the above reaction scheme, R9 represents a lower alkyl group, such as methyl or ethyl, and R2 and R4 are as defined above).

In this reaction scheme, a 3-(4-acylaminobenzoyl)propionic acid of formula (V-3), which is obtained by reaction of a 4-acylamino-benzene of formula (VI-3) with succinic anhydride, is subjected to halogenation, deacylation, reaction with hydrazine and dehydrogenation, in any order.

. ' The first step in this reaction~ the reaction of compound (VI-3) with succinic anhydride to give compound (V-3), may be carried out as described with reference to step (c-1) of Process I.

The deacylation reaction, in which compound (V-3) is con-verted to compound (V-S), compound (V-4) is converted to compound (V-6)~
compound (IV-3) is converted to compound (IV-4) or compound (III-2) is converted to compound (III-3),may be carried out by reacting the appropriate compound with a deacylating agent in an inert solvent in the presence of an acid or a base. There is no particular limitation on the inert solvent to be employed, provided that it does not interfere with the reaction and examples of preferred solvents are as follows:
alcohols, such as methanol, ethanol, propanol or butanol; cyclic ethers, such as dioxan or tetrahydrofuran; ketones, such as acetone or methyl ethyl ketone; and water. Examples of acids and bases which may be employed are: inorganic acids, such as hydrochloric acid, sulphuric acid or orthophosphoric acid; and inorganic bases, such as sodium hydroxide, potassium hydroxide, sodium carbonate or potassium carbonate. The reaction is preferably carried out at a temperature ranging from room f temperature to the reflux temperature of the solvent employed.

The halogenation of compound (V-3) to give compound (V-4) may be carried out by reacting compound (V-3) with a halogenating agent -j in an inert solvent in the presence of a Lewis acid, as described with reference to step (c-2) of Process I.

Compound (V-5) may be converted to compound (V-6) or compound (III-3) may be converted to compound (III-4) merely by heating compound (V-S) or compound (III-3? with a halogenating agent in the presence of an inert solvent. Examples of halogenating agents which may be employed are chlorine, bromine, iodine, iodine monochloride, N-chlorosuccinimide, N-bromosuccinimide, an aqueous solution of sodium hypochlorite or a ; 15 mixture of hydrochloric acid and aqueous hydrogen peroxide. There is no particular l;mitation on the nature of the solvent employed, provided that it does not interfere with the reaction and examples of suitable solvents are: halogenated hydrocarbons~ such as tetrachloroethane~ dichloroethane, ~-dichloromethane, carbon tetrachloride and chloroform; organic acids, such as acetic acid and propionic acid; and water. The reaction is preferably carried out at a temperature ranging from room temperature to the reflux temperature of the solvent employed. The reaction time will depend upon , the reaction temperature and the reagents employed but will generally range from 1 to 24 hours.

The conversion of compound (V-3), (V-5) or (V-6) to compound : (IV-3), (IV-4) or (IY-5), respectively, may be carried out by reaction with hydrazine, as described with reference to step (c-3) of Process I.

The dehydration of compound (IV-3), (IV-4) or (IV-5) to give compound (ITI-2)~ (III-3) or (III-4), respectively~ may be effected as described with reference to step (a) of Process I.

_ OCESS III
Compounds in which R3 represents a hydroxyl group may be prepared as shown in the following reaction scheme:

R2~ Rl R~Q~OH
., Rl,a , 7) Halogenation HOB~OH--110~ I H ~ 8~ ~1 IV~ 1 61 1D}5) (In which R3a represents a lower alkoxy group, such as methoxy, and R , R , R4, R a and R4a are as defined above).

As shown in the reaction scheme, a 3-(4-alkoxybenzoyl)propionic acid (V-7) is halogenated, dealkylation automatically occurring simultane-ously, to give a 3-(4-hydroxybenzoyl)propionic acid of formula (V-8). The halogenation preferably is carried out by reacting compound (V-7) with a halogenating agent in an inert solvent and in the presence of a Lewis acid, as described with reference to step (c-2) of Process I.

, The 3-(4-hydroxybenzoyl)propionic acid of formula (V-8) is then reacted with hydrazine, substantially as described with reference to step (c-3) of foregoing Process I, to give a compound of formula (n -6), which may be the desired compound and may thus be isolated and ` purified using conventional methods. Alternatively, the compound of formula (IV-6) may be dehydrogenated, substantially as described with ; 15 reference to step (a) of foregoing Process I, to give a compound of formula (III-S).
. , .

PROCESS IV
Pyridazinone derivatives of formula (I) and/or (II) wherein R3 represents an alkoxy~ alkenyloxy or alkynyloxy group may be prepared 20 as illustrated by the following reaction scheme:

.

: , , , , , - - , , . . . . : . . :
, .. . .
. . . .. . . .. .

1082~90 ~
~ .

~~10 , ~o~ W~O

V- 9) . IlV-l~) llV-5) R2 Id- 1 ) R2 Id - 2) R2 ld -3) ~_ 10NH21~H2 3b~?,ol H2~ R3~ o ; ~ IV-1D) R Im-g) H R l~l-10) H
.

.

~-; 10 (In the àbove reaction scheme, R10 represents a hydrogen atom or an alkyl '~ group, e.g. methyl, ethyl or propyl, R3b represents an alkoxy group, an alkenyloxy group or an alkynyloxy group, and R2 and R4 are as defined abo~e).

The desired compound of formula (III-9) or (III-10), which has an aIkoxy, alkenyloxy or alkynyloxy group at the 4- position of the benzene ring, can be prepared by the following sequences of steps:

(A) A 3-(4-hydroxybenzoyl)propionic acid or ester thereof of -~ 5 formula (V-9) is subjected to alkylation, alkenylation or alkynylation in step (d-1)~ to give a compound of formula (V-10)~ which i9 then reacted with hydrazine to give a 6-(4-substituted phenyl)-4,5-dihydro-3(2H)-pyridazinone of formula (III-9); if desired~ this may then be dehydro- .
genated to give the desired compound of formula (III-10).
:.
10 (B) Compound (V-9) is reacted with hydrazine to formcompound (IV-4) and this is then dehydrogenated to form a 6-(4-hydroxy- ]
phenyl)-3(2H)-pyridazinone of formula (IV-5), which is then subjected to alkylation, alkenylation or alkynylation in step (d-3) to give the desired 3 : compound of formula (III-10).

(C) Compound (V-9) is first reacted with hydrazine to form the compound of formula (IV-4), which is then alkylated, alkenylated or alkynylated in ætep (d-2) to give compound (III-9) and then, if desired, dehydrogenated as above.

The compound of formula (V-93 in which R10 represents an alkyl group may be prepared by conventional esterification o~ a 3-(4-hydroxybenzoyl)propionic acid produced as described in Process III.

., . . . . . ,. . -: . . : .
., .. : . .: ....

108~190 The alkylation, alkenylation or alkynylation of compound (V-9), (IV-4) or (IV-5) to form compound (V-10), (III-9) or (III-10), respectively, is preferably effected in the presence of an inert solvent and preferably in the presence of a catalyst. Examples of S alkylating, alkenylating or alkynylating agents ~hich may be employed in this reaction are: dialkyl sulphates, such as dimethyl sulphate or diethyl sulphate; alkyl, alkenyl or alkynyl halides, such as methyl iodide, ethyl iodide, ethyl bromide, propyl bromide, methyl chloride, allyl bromide, 2-methyl-3-bromo-1-propene or 3-bromo-1-propyne; tri-alkyl phosphites~ such as trimethyl phosphite or triethyl phosphite;
and diazomethane.
. , .
- Where the alkylating, alkenylating or alkynylating agent is a dialkyl sulphate or an alkyl, alkenyl or alkynyl halide, the reaction is preferably carried out in the presence of a catalyst.
Examples of suitable catalysts are inorganic bases (such as sodium ., hydroxide, potassium hydroxide, sodium carbonate or potassium carbonate) and tertiary amines (such as triethylamine, triethylenediamine or N,N-dimethylani1ine). There is no particular limitation on the nature of the inert solvent, provided that it does not interfere with the reaction and examples of suitable solvents are: alcohols, such as methanol3 ethanol or propanol; ketones~ such as acetone or methyl ethyl ketone;
~; ethers~ such as diethyl ether, tetrahydrofuran or dioxan; aromatic hydrocarbons, such as benzene, *oluene or xylene; dialkylformamides~

.
, .

:, . . .
- . . . . . . . . . . . . . .
, , . :. : , .. .... .
,, , . ~ . , . ,.. , :

such as dimethylformamide or diethylformamide; and water.
:
The reaction of compound (V-9) or (V-10) with hydrazine to produce compound (IV-4) or (III-9)~ respectively~ may be conducted as described with reference to step (c-3) of Process I.

The reaction of compound (IV-4) or compound (III-9) with a dehydrogenating agent to produce compound (IV-5) or compound (III-10), . . , respectively, may be conducted as described with reference to step (a) of foregoing Process I.
~; .
PROCESS V .
Compounds of formula (I) and/or (II) wherein R1 represents the group -o-Co-R5 or -0-S02-R6 (in which R5 and R6 are as defined -~ above) may be prepared by reaction of the corresponding compound wherein R1 represents a hydroxy group with a halide or anhydride of a carboxylic : acid or with a benzenesulphonic acid halide~ as shown in the following scheme:

~N-N>=0 6 R~ >'0 R~ H R~ H
ll~l- 6) (1~1-11) ., .

' ' , . ', ,' - ' ' '' . "~,"'' ~ ' ' ~

(In these formulae, R3c represents a hydrogen atom, an alkyl group, an alkoxy group, an alkenyloxy group, an alkynyloxy group or a halogen atom;
Rla represents the group -o-Co-R5 or -0-S02-R6, in which R5 and R6 are as defined above; X represents a halogen atom or the group -0-C0-R5, RS being as defined above; Y represents a halogen atom; and R2, R4, and A are as defined above).

The reaction of compound (VI~6) with a carboxylic acid halide or anhydride or with a benzenesulphonic acid halide to form compound (III-11) is preferably conducted in the presence of an inert solvent and in the presence or absence of a catalyst. To introduce the group -0-C0-R5, compound (YI-6) may be reacted with a lower aliphatic acid halide or anhydride, for example acetyl chloride, propionyl chloride, butyryl chloride, isovaleroyl chloride, hexanoyl chloride, acetic anhydride, propionic anhydride or butyric anhydride. To introduce the group -O-S02-R6, compound (VI-6) is reacted ~.~ith a benzenesulphonic acid halide, for example benzenesulphonyl chloride, p-toluenesulphonyl chloride, ~-chloro-benzenesulphonyl chloride or 2,4-dichlorobenzenesulphonyl chloride.
Where a benzenesulphonic acid halide or a lower aliphatic acid halide is used, the reaction is preferably conducted in the presence of a catalyst, preferably an inorganic base (such as sodium hydroxide, potassium hydroxide, sodium carbonate or potassium carbonate) or a tertiary amine -(such as triethylamine, triethylenediamine or N,N-dimethylaniline).
There is no particular limitation on the solvent employed, provided that it does not interfere with the reaction. Examples of suitable solvents

- 36 -108Zl90 ,-are: ketones, such as acetone or methyl ethyl ketone; ethers, such as diethyl ether, tetrahydrofuran or dioxan; aromatic hydrocarbons, such as benzene, toluene or xylene; halogenated alkanes, such as chloroform, dichloromethane or dichloroethane; dialkylformamides, ~ 5 such as dimethylformamide or diethylformamide; and organic acids, : such as acetic acid, propionic acid or butyric acid. The reaction may be carried out at temperatures ranging from room temperature to the reflux temperature of the solvent employed.

PROCESS VI
Compounds in ~lich Rl represents a hydrogen atom and R3 represents the group -o-Co-R5 or -0-S02-R6 may be prepared according to the following reaction scheme:
~, 'i R2 R2 ~O~_h>'=D orRSS02V ,~<N~h')=

lIV- 7) l]n-12) (in ~hich R3d represents the group -o-Co-R5 or -0-S02-R6, R5 and R6 ~ being as defined above~ X represents a halogen atom or the group -o-Co-R5, Y represents a halogen atom and R2~ R4 and A are as defined : above).

~ - 37 ~

~ .

s As shown in the above reaction scheme, compounds of formula (III-12) having the group -o-Co-R5 or -0-S02-R6 at the 4-position of the benzene ring, may be prepared by reacting a 6-(4-hydroxyphenyl)-3(2H)-pyridazinone of formula (IV-7) with a carboxylic acid halide or anhydride or with a benzenesulphonic acid halide.

This process may be carried out in the manner described above with regard to Process V.

PROCESS VII
, Acid addition salts of compounds of formula (I) wherein A represents the group -CH=CH- with a mineral acid may easily be formed by intimately contacting the compound (I) with the desired mineral acid in an appropriate solvent. There is no particular limitation on the solvent to be employed and examples of suitable solvents are:
water; alcohols, such as methanol or ethanol; ethers, such as tetra-hydrofuran or dioxan; aromatic hydrocarbons, such as benzene;
halogenated hydrocarbons, such as dichloromethane or chloroform;
ketones, such as acetone; or a mixture of one or more thereof with water. Generally a salt with a mineral acid is formed where the pH of the solution is not more than 3.

A salt of a compound of formula (I) wherein A represents the group -CH=CH- with a metal may be formed by treating a solution of such a compound with the desired cation in the presence of the solvent. There is no particular limitation on the nature of the solvent and examples are: water; alcohols, such as methanol or ethanol; ethers, such as tetrahydrofuran or dioxan; aromatic S hydrocarbons, such as benzene; halogenated aliphatic hydrocarbons, such as dichloromethane or chloroform; and mixtures of one or more thereof with water. Various salts may be formed in which the -coordination ratio of the compound (I) to the cation varies, such ratios being, for example, 1:1, 1:2 or 1:3, depending upon the valency of the cation and the solvent employed.

Adducts of a compound of formula (I) wherein A represents the group -CH=CH- with an alkyl isocyanate may be formed by reacting ; the compound (I) with the alkyl isocyanate in the presence or absence of a solvent. If a solvent is employed, there is no particular limi-tation upon its nature, provided that it does not interfere with the reaction; examples of suitable solvents are toluene, xylene, dimethyl-formamide, dimethyl sulphoxide, dioxan, tetrahydrofuran, ethylene glycol diethyl ether or acetonitrile. The reaction temperature is not critical and the reaction may be carried out at temperatures ranging from below ambient to the reflux temperature of the solvent employed;
room temperature is most convenient.

The compounds of formula (I) and salts thereof may be employed as agricultural fungicides and show a preventive and curative effect against plant diseases, without damaging the host plants.

Specifically, they are particularly effective in the control of sheath blight, which is a very serious disease attacking rice plants; for this use, they are preferably employed in the form of a spray, particularly a surface spray. They also effectively control damping-off of various crops, such as beet, cotton plants and plants of the gourd family~ which is caused by pathogenic fungi of the class Rhizoctonia,and are effective in the control of infectious soil borne diseases, for example southern blight (which attacks the egg-plant and plants of the gourd family) and black scurf (which attacks potatoes); in this case, it is preferably employed in the form of a soil fungicide or seed disinfectant.

; At effective doses, the compounds of formula (I) do not exhibit any phytotoxicity to such plants as rice plants, tomato plants, potatoes, cotton plants, égg-plants, cucumbers and kidney beans.
Moreover, the compounds of formula (I) and salts thereof may be effectively used as fungicides in orchards~ non-crop land and forests.

.
. ' , .
-108Z~90 The compounds of the invention may be formulated as preparatians of the type commonly used as agricultural fungicides, for example powdery dusts, coarse dusts, fine granules, coarse granules, wettable powders, emulsifiable concentrates, aqueous liquids, water-soluble powders, and oil suspensions, by mixing them with a carrier and, if required, another auxiliary agent. The carrier employed may be natural or synthetic and organic or inorganic; it is mixed with the active ingredient~ the compound of formula (I),to assist that active compound to reach the material to be treated, and to make it easier to store, transport or handle the active compound. Suitable solid carriers are: inorganic substances, such as clays (examples of which are kaolinite, montmorillonite and attapulgite), talc, mica, pyrophyllite, pumice, vermiculite, gypsum, calcium carbonate, dolomite, diatomaceous earth, magnesium carbonate, apatite, zeolite, silicic anhydride and synthetic calcium silicate; vegetable organic substances, such as soybean meal, tobacco powder, walnut powder, wheat flour, wood meal, starch and crystalline cellulose; synthetic or natural high molecular weight polymers, such as cumarone resins, petroleum resins, alkyd rcsins, polyvinyl chloride, polyalkylene glycols~ ketone resins, ester gums~ copal gums and dammar gums; waxes, such as carnauba wax and beeswax; or urea. Examples of suitable liquid carriers are: para- ;~
ffinic or naphthenic hydrocarbons, such as kerosine, mineral oil, spindle ' ~ ~ .
-- 41 _ . . .

., oil and white oil; aromatic hydrocarbons, such as benzene, toluene, xylene, ethylbenzene, cumene and methylnaphthalene; chlorinated hydro-carbons, such as carbon tetrachloride, chloroform, trichloroethylene, monochlorobenzene and o-chlorotoluene; ethers, such as dioxan and tetrahydrofuran; ketones, such as acetone, methyl ethyl ketone, di-isobutyl ketone, cyclohexanone, acetophenone and isophorone; esters, such as ethyl acetate, amyl acetate, ethylene glycol acetate, diethylene glycol acetate, dibutyl maleate and diethyl succinate; alcohols, such -¦
as methanol, hexanol, ethylene glycol, diethylene glycol, cyclohexanol and benzyl alcohol; ether alcohols, such as ethylene glycol monoethyl ether, ethylene glycol monophenyl ether, diethylene glycol monoethyl ether and diethylene glycol monobutyl ether; other polar solvents, such as dimethylformamide or dimethyl sulphoxide; and water.

The fungicidal compositions of the present invention may contain surface active agents to emulsify, disperse, wet, spread, bind, control disintegration, improve fluidity or rust-proof the fungi-cidal composition or to stabilise the active compound; although any of the conventional classes of surface active agent, be they non-ionic, anionic, cationic or amphoteric, may be employed, we prefer to employ non-ionic and/or anionic surface active agents. Examples of suitable non-ionic surface active agents are: the polymerisation adducts of ; ethylene glycol with higher alcohols, such as lauryl alcohol, stearyl .
'' ' ' :

~ .
. ~.
alcohol and oleyl alcohol; the polymerisation adducts of ethylene oxide ~ with alkylphenols, such as isooctylphenol and nonylphenol; polymerisation adducts of ethylene glycol with alkylnaphthols, such as butylnaphthol or octylnaphthol; polymerisation adducts of ethylene oxide with higher fatty acids, such as pal~itic acid, stearic acid or oleic acid; polymerisation adducts of ethylene oxide with mono- or di- alkylphosphoric acids, such as stearylphosphoric acid and dilaurylphosphoric acid; polymerisation adducts of ethylene oxide with amines, such as dodecylamine; polymerisation : adducts of ethylene oxide with higher fatty acid amides, such as steara-mide; polymerisation adducts of ethylene oxide with higher fatty acid esters of polyhydric alcohols, such as sorbitan, and said fatty acid esters; and polymerisation adducts of ethylene oxide with propylene oxide. Examples of suitable anionic surface active agents are: alkyl sulphate salts, such as sodium lauryl sulphate and oleyl sulphate amine salt; alkyl sulphonate salts, such as sodium diociyl sulphosuccinate and sodium 2-ethylhexene sulphonate; and aryl sulphonate salts, such as sodium isopropylnaphthalene sulphonate, sodium methylenebisnaphthalene - sulphonate, sodium ligninsulphonate and sodium didecylbenzene sulphonate.

~oreover, the agricultural fungicidal compositions of the ~0 present invention may be used in combination with high molecular weight compounds or other auxiliary agents, such as casein, gelatin, albumin, :~

.

' ' .
' ' 108z190 glue, sodium alginate, carboxymethylcellulose, methylcellulose, hydroxy- '~
ethylcellulose or polyvinyl alcohol, in order to improve the properties and/or increase the biological effect of the composition.

The above-mentioned carriers and various auxiliary agents S may be used alone or in any desired combination, depending on the type of preparation, the application and other factors.

In general, the fungicidal composition of the present invention may contain the active compound of formula (I) in an amount of from 0.1 to 99% by weight, based on the composition.

Dusts may conveniently contain, for example, from 1 to 25 parts by weight of the active compound (I), the remainder being a solid carrier.

l~ettable powders may conveniently contain, for example, from 25 to 90% by weight of the active compound (I), the remainder being a solid carrier and a dispersing and wetting agent, if required, together with a protective colloidal agent, a thixotropic agent and an anti-foaming agent.

Granules may conveniently contain from 1 to 35% by weight of the active compound (I), a major portion of the remainder being a solid carrier. The active compound is homogeneously admixed with the 1082~90 ~.

solid carrier or adhered or adsorbed onto the carrier surface; the size of each granule is preferably from 0.2 to 1.5 mm. -Emulsifiable concentrates may conveniently contain, for example, from 5 to 50% by weight of the active compound and from 5 to 20% by weight of an emulsifying agent, the remainder being a liquid carrier, together with a corrosion inhibitor, if required.
-I
The fungicidal compositions of the present invention, which are formulated into the various types of preparations described above, may be applied to a paddy or upland (dry) field in an amount of from 1 to 5,000 g, more preferably from 10 to 1,000 g of the active compound ` (I) per 10 ares for pre- or post- emergence fungicidal activity; it may be applied by foliage spraying, soil drenching or spraying onto irrigation water. The fungicidal compositions of the present invention, when employed for seed disinfection or coating~ effectively control ?
soil-borne or seed infectious diseases by coating seeds in an amount of from 0.1 to 2%, preferably from 0.2 to 0.5%, by weight of the active ingredient, based on the weight of the seed.

The fungicidal compositions of the present invention may be - blended with other fungicides for a broader fungicidal spectrum and, in some cases~ a synergistic effect may be observed. Examples of other .; , - 45 ~

. . .
"` : ' fungicides which may be employed in combination with the fungicidal composition of the present invention are: carbamate-type fungicides, such as 3,3~-ethylenebis(tetrahydro-4,6-dimethyl-2= 1,3,5-thiadiazine-2-thione, ~ zinc or manganese ethylenebisdithiocarbamate~ bis(dimethyldithiocarbamoyl) - 5 disulphide, zinc propylenebisdithiocarbamate, bis(dimethyldithiocarbamoyl)-ethylenediamine, nickel dimethyldithiocarbamate, methyl l-(butylcarbamoyl) -2-benzimidazolcarbamate, 1~2-bis(3-methoxycarbonyl-2-thioureido)benzene~ ¦
l-isopropylcarbamoyl-3-(3,5-dichlorophenyl)hydantion, potassium N-hydroxy-methyl-N-methyldithiocarbamate and 5-methyl-10-butoxycarbonylamino-10,11-dehydrodibenzo~ ,~ azepine; pyridine-type fungicides, such as zinc bist -hydroxy-2(1H)-pyridinethionat~ and sodium 2-pyridinethiol-1-oxide;
phosphorus-containing fungicides, such as 0,0-diisopropyl-S-benzyl-phosphorothioate and 0-ethyl-S,S-diphenyldithiophosphate; phthalimide-type fungicides, such as N-(2~6-diethylphenyl)phthalimide and N-(2,6-diethylphenyl)-4-methylphthalimide; dicarboximide-type fungicides, such as N-trichloromethylthio- 4cyclohexene-1,2-dicarboximide and N-tetra-chloroethylthio-4-cyclohexene-1,2-dicarboximide; oxazine-type fungicides, such as 5~6-dihydro-2-methyl-1,4-oxazine-3-carboxanilide-4,4-dioxide and 5,6-dihydro-2-methyl-1,4-oxazine-3-carboxanilide; naphthoquinone-type fungicides~ such as 2,3-dichloro-1,4-naphthoquinone and 2-oxy-3-chloro-1,4-naphthoquinone copper sulphate adduct; and other fungicides, such as pentachloronitrobenzene, 1,4-dichloro-2,5-dimethoxybenzene, 5-methyl s-triazole(3,4-b)benzthiazole~ 2-(thiocyanomethylthio)benzthiazole, 3-hydroxy-5-methylisoxazole~ N-(2~3-dichlorophenyl)tetrachlorophthalamidic acid, 5-ethoxy-3-trichloromethyl-1,2~4-thiadiazole~ 2,4~6-trichloro-6--: :

.. ...,, , ~ . .
. . . , . ~ . :
, 108;~190 ~-chloroanilino)-1,3,5-triazine, 2,3-dicyano-1,4-dithioanthraquinone, copper 8-quinolate, polyoxin, validamycin, cycloheximide, iron methane-arsonate, diisopropyl-1,3-dithioran-2-ylidene malonate, 3-allyloxy-1,2-benzoisothiazole 1,1-dioxide, kasugamycin, blasticidin S and 4,5,6,7-tetrachlorophthalide; however, the nature-of such additional fungicides is not critical.

.
The fungicidal composition of the present invention may , also be employed in admixture with plant growth regulators, herbicides or insecticides. Examples of plant growth regulators are: the isourea-type plant growth regulators, such as N-methoxycarbonyl-N~-4-methylphenyl-carbamoylethyl isourea and 1-(4-chlorophenylcarbamoyl)-3-ethoxycarbonyl-2-methyl isourea; sodium naphthyl acetate; 1,2-dihydropyridazine-3,6-dione; and the gibberellins. Examples of herbicides which may be employed with the fungicidal composition of the present invention are:
triazine-type herbicides, such as 2-methylthio-4-6-bisethylamino-1,3,5-triazine, 2-ehloro-4,6-bisethylamino-1,3,5-triazine, 2-methoxy-4-~ ethylamino-6-isopropylamino-1,3,5-triazine, 2-chloro-4-ethylamino-6-- isopropylamino-s-triazine, 2-methylthio-4,6-bis(isopropylamino)-s-I triazine and 2-methylthio-4-ethylamino-6-isopropylamino-s-triazine;phenoxy-type herbicides, such as 2,4-dichlorophenoxyaeetie acid and its ; methyl, ethyl or butyl esters, 2-ehloro-4-methylphenoxyacetic acid,4-chloro-2-methylphenoxyacetic acid and ethyl 2-methyl-4-chlorophenoxy-butyrate; diphenyl ether-type herbicides, such as 2,4,6-trichloro-- 47 ~

, : . : . .
,,'' ~:
.

-.
phenyl 4-nitrophenyl ether, 2,4-dichlorophenyl 4-nitrophenyl ether and 3,5-dimethylphenyl 4-nitrophenyl ether; urea-type herbicides, such as 3-(3~4-dichlorophenyl)-1-methoxy-1-methylurea, 3-(3,4-dichlorophenyl)-1,1-dimethylurea and 3-(4-chlorophenyl)-1,1-dimethylurea; carbamate-type herbicides, such as 3-methoxycarbonyl-aminophenyl-N-(3-methylphenyl)-carbamate, isopropyl N-(3-chlorophenyl)-carbamate and methyl N-(3,4-dichlorophenyl)carbamate; uracil-type herbicides, such as 5-bromo-3-sec-butyl-6-methyluracil and 1-cyclohexyl-3,5-propyleneuracil; thiocarbamate-type herbicides, such as S-t4-chlorobenzyl)-N,N-diethylthiolcarbamate~ S-ethyl-N-cyclohexyl-N-ethylthiolcarbamate, S-ethyl-hexahydro-lH-azepine-1-carbothioate and S-ethyl-N,N-dipropylthiocarbamate; pyridinium salt herbicides, such as 1,1~-dimethyl-4-4~-bispyridinium dichloride; phosphorus-containing herbicides, such as N-(phosphonomethyl)glycine; aniline-type herbicides, such as ~,e-trifluoro-2,6-dini*ro-N,N-dipropyl-p-toluidine and 4- -~
(methylsulphonyl)-2,6-dinitro-N,N-dipropylaniline; acid anilide-type herbicides, such as 2-chloro-2~,6~-diethyl-N-(butoxymethyl)acetanilide, 2-chloro-2~,6~-diethyl-N-(methoxymethyl)acetanilide and 3,4-dichloro-propionanilide; pyrazole-type herbicides, such as 1,3-di~ethyl-4-(2,4-dichlorobenzoyl)-5-hydroxypyrazole and 1,3-dimethyl-4-(2~4-dichloro-benzoyl)-5-(~-toluenesulphonyloxy)pyrazole; 5-t-butyl-3-(2,4-dichloro-5-isopropoxyphenyl)-1,3,4-oxadiazolin-2-one; 2-r N-isopropyl-N-(4-chlorophenyl)-carbamoyy -4-chloro-5-methyl-4-isoxazolin-3-one; 3-iso-propylbenzo-2-thia-1,3-diazinon-(4)-2,2-dioxide; and 3-(2-methylphenoxy)-108'~190 pyridazine. Suitable insecticides are: phosphorus-containing insecticides, such as 0,0-diethyl 0-(2-isopropyl-4-methyl-6-pyrimidinyl) phosphorothioate, 0~0-diethyl S-2-~ ethylthio)ethy~ phosphorodithioate, 0,0-dimethyl 0-(3-methyl-4-nitrophenyl)thiophosphate, 0,0-dimethyl S-(N-methylcarbamoylmethyl)phosphorodithioate, 0,0-dimethyl S-(N-methyl-N-formylcarbamoylmethyl)phosphorodithioate, 0~0-dimethyl S-2-(ethyl-thio)ethylphosphorodithioate, 0,0-diethyl S-2-~ethylthio)ethyy phos-phorodithioate, 0,0-dimethyl-1-hydroxy-2,2,2-trichloroethylphosphonate, 0,0-diethyl-= (5-phenyl-3-isoxazolyl)phosphorothioate~ methyl (4-bromo-2,5-dichlorophenyl)phenylphosphonothioate, 0,0-dimethyl-= (3-methyl-4-methylmercaptophenyl)thiophosphate, 0-ethyl-0-E-cyanophenyl phenyl-~ phosphonothioate, 0,0-diethyl S-(1,2-dicarboethoxyethyl)phosphoro--` dithioate, 2-chloro-1-(~,4,5-trichlorophenyl)vinyldimethyl phosphate, .~ 2-chloro-1-(2,4-dichlorophenyl)vinyldimethyl phosphate, 0,0-dimethyl 0-E~cyanophenyl phosphorothioate, 2,2-dichlorovinyl dimethyl phosphate, 0,0-diethyl 0-2~4-dichlorophenyl phosphorothioate, ethyl mercaptophenyl-acetate 0~0-dimethyl phosphorodithioate~ S-~ 6-chloro-2-oxo-3-benzo-oxazolinyl)methy~ 0,0-diethylphosphorodithioate, 4-mercaptothiophenyl dipropylphosphate, 2-chloro-1-(2,4-dichlorophenyl)vinyl diethylphosphate, 0,0-diethyl-= (3-oxo-2-phenyl-2= W ridazin-6-yl)phosphorothioate, 0,0-dimethyl S-(1-methyl-2-ethylsulphinyl)ethyl phosphorothiolate, 0,0-dimethyl S-phthalimidomethyl phosphorodithioate, dimethylmethylcarbamoyl-~ 49 -.

~, . . .

ethylthioethyl thiophosphorothiolate, 0,0-diethyl S-(N-ethoxycarbonyl-N-methylcarbamoylmethyl)phosphorodithioate, 0,0-dimethyl-S-~ -methoxy-1,3-4-thiadiazol-5(4H)-onyl-(4)-methy~ dithiophosphate, 2-methoxy-4H-1,3,2-benzodioxaphosphorin 2-sulphide, 0~0-diethyl-0= (3,5,6-trichloro-2-pyridyl)phosphorothioate, 0-ethyl-0= 2,4-dichlorophenyl thionobenzene phosphonate, S-~ ,6-diamino-s-triazin-2-yl-methy~ -0,0-dimethyl phos-phorodithioate~ 0-ethyl 0-~-nitrophenylphenylphosphorothioate, 0,S-dimethyl-N-acetyl phosphoroamidothioate, 2-diethylamino-6-methylpyrimidin-4-yl-diethylphosphorothioate~ 0,0-diethyl 0-~-(methylsulphinyl)phenyl phosphorothioate, 0-ethyl-S-propyl 0-2,4-dichlorophenylphosphorodithioate and cis-3-(dimethoxyphosphinoxy)-N-methyl-cis-crotonamide; carbamate-type insecticides, such as 1-naphthyl N-methylcarbamate, S-methyl-N-~ ethyl-carbamoylox~ thioacetoimidate, m-tolyl methylcarbamate, 3,4-xylyl methylcarbamate, 3,5-xylyl methylcarbamate, 2-sec-butylphenyl-N-methyl-carbamate, 2~3-dihydro-2~2-dimethyl-7-benzofuranylmethylcarbamate~ 2-isopropoxyphenyl-N-methylcarbamate, 1~3-bis(carbamoylthio)-2-(N,N-dimethylamino)propane hydrochloride and 2-diethylamino-6-methylpyrimidin-4-yl dimethyl carbamate; and other insecticides, such as N,N-dimethyl-: Nl-(2-methyl-4-chlorophenyl) formamidine hydrochloride, nicotine sulphate, silbemycin~ 6-methyl-2,3-quinoxalinedithiocyclic S,S-dithiocarbonate, 2,4-dinitro-6-sec-butylphenyl dimethylacrylate, 1,1-bis(~-chlorophenyl) 2,2,2-trichloroethanol, 2-(E-t-butylphenoxy)isopropyl-2~-chloroethyl-sulphite, azoxybenzene, di-(~-chlorophenyl)-cyclopropyl carbinol, .. . . . .

di~ ri(2,2-dimethyl-2-phenylethyl)ti~ oxide, 1-(4-chlorophenyl)-3-(2~6-difluorobenzoyl)urea and S-tricyclohexyltin 0,0-disopropyl phosphorodithioate. Fertilisers may also be incorporated in the fungicidal composition.

The fungicidal composition of the invention can be used with a control agent against rice blast, helminthosporium leaf spot, bacterial leaf blight, rice stem borer, planthopper and/or leafhopper for effective labour saving. A combination of one or more of the agents described above with the fungicidal composition of the present invention may be employed, depending upon the disease and/or insect to be controlled and the form of the fungicidal composition to be ~- employed. I~e particularly prefer to employ the fungicidal composition of the invention in the form of a dust for controlling rice plant diseases and/or soil treatment.

The preparation of compounds of formula (I) and (II) and fungicidal compositions containing compounds of formula (I) are further illustrated by the following non-limiting Examples.

E3~PLE 1 Preparation of 6-(3,5-dichloro-4-methylphenyl)-4,5-dihydro-3(2H)-Pyridazinone (Compound 93).
(a) 4-~35~dichloro-4-methylphenyl)-4-oxobutyric acid.

. -',' To a suspension of 19.22 g of 4-(4-methylphenyl)-4-oxobutyric acid in 1 litre of dichloroethane were carefully added 400 g of aluminium chloride, while stirring the suspension and maintaining it at a tempera-ture not higher than 10C. The reaction vessel was then cooled to 0C
and about 175.5 g of chlorine gas were introduced into it over a period of 13 hours. The reaction mixture was then left overnight, after which it was poured into a mixture of 1.8 Kg of ice and 300 ml of concentrated hydrochloric acid, whilst stirring vigorouslY. After leaving the mixture for a while, the upper layer wllich separated out was removed by decantation and 800 ml of hexane were added to the lower layer, causing a crystalline substance to separate. This crystalline substance ~as recovered by filtration, washed with water un~il the washings beeame approximately neutral, dried and then recrystallised from 1.8 litres of toluene to give 156.2 g of crude crystals. These crystals were recrystal-lised from 2 litres of acetonitrile, to give 135.3 g of 4-(3~5-dichloro-4-methylphenyl)-4-oxobutyrie acid~ in the form of colourless needles m.p.
185 - 187C.
, ,.

Following the same procedure, the following compounds were prepared:
4-(3-chloro-4-methylphenyl)-4-oxobutyric acid, m.p. 151 - 153C.
4-(3-bromo-4-methylphenyl)-4-oxobutyric aeid, m.p. 165 - 171C.

.
'. ., . : ' : , . : .

108Zl90 4-(3-chloro-4-isopropylphenyl)-4-oxobutyric acid, m.p. 117 - 118C.
4-(3,5-dibromo-4-methylphenyl)-4-oxobutyric acid, m.p. 188 - 191C.
4-(3,5-dichloro-4-ethylphenyl)-4-oxobutyric acid, m.p. 137 - 138 &.
4-(3,5-dichloro-4-propylphenyl)-4-oxobutyric acid~
m.p. 133 - 134C.
4-(3,5-dichloro-2-hydroxy-4-methylphenyl)-4-oxobutyric acid, m.p. 185 - 187C.
4-(3-chloro-4-ethylphenyl~-4-oxobutyrie acid, m.p. 160 - 161 &.
4-(3-bromophenyl)-4-oxobutyrie acid, m.p. 114 - 119C.
4-(3-ehlorophenyl)-4-oxobutyrie aeid, m.p. 107 - 109C.
4-(4-butyl-3,5-diehlorophenyl)-4-oxobutyrie acid, - m.p. 120 - 122C.
4-(3-ehloro-4-fluorophenyl)-4~oxobutyrie aeid, m.p. 98 - 101C.
4-(3-bromo-4-ehlorophenyl)-4-oxobutyrie aeid, m.p. 160 - 163C.
4-(3-bromo-4-fluorophenyl)-4-oxobutyrie aeid, m.p. 121 - 124&.
4-(3~4,5-triehlorophenyl)-4-oxobutyrie aeid, m.p. 159 - 163C.

:, . ::

4-(4-bromo-3-chlorophenyl)-4-oxobutyric acid~
m.p. 175 - 178C.

(b) Compound 93.
15.6 g of the 4-(3,5-dichloro-4-methylphenyl)-4-oxobutyric acid prepared in step (a) above were dissolved by heating to about 50C
in 120 ml of ethanol; 3.28 g of hydrazine hydrate were then added dropwise, with stirring~ to the resulting solution. After completion of the drop~ise addition, the mixture was heated under reflux for about .
1 hour. The mixture was then cooled and the crystalline substance which separated out was recovered by filtration, washed with ethanol and dried, giving 13.4 g of Compound 93 in the form of colourless crystals melting at 204 - 205C.
~ ~ .
Following the procedure described above~ the following compounds were prepared:
, . ~
6-(3,4-dichlorophenyl)-4~5-dihydro-3(2H)-pyridazinone, (Compound 87) m.p. 176 - 179&.
6-(3-chloro-4-methylphenyl)-4,5-dihydro-3(2H)-pyridazinone, (Compound 90) m.p. 160 - 162C.
6-(3-bromo-4-methylphenyl)-4,5-dihydro-3(2H)-pyridazinone, ~Co~pound 91) m.p. 150 - 153C.
6-(3-chloro-4-isopropylphenyl)-4,5-dihydro-3(2H)-pyridazinone, (Compound 92) m.p. 153 - 157C.
.
~ 54 -., , , . , :, . .
.

1082~9 6-(3,5-dibromo-4-methylphenyl)-4,5-dihydro-3(2H)-- pyridazinone~ (Compound 94) m.p. 196 - 202C.
6-(3,5-dichloro-4-ethylphenyl)-4,5-dihydro-3(2H)- Jpyridazinone, (Compound 96) m.p. 164 - 166C.
6-(3,5-dichloro-4-propylphenyl)-4,5-dihydro-3(2H)-pyridazinone, (Compound 98) m.p. 205 - 207C.
6-(3~5-dichloro-2-hydroxy-4-methylphenyl)-4~5-dihydro-3(2H)-pyridazinone, ~ompound 108) m.p. above 300C.
6-(3-chloro-4ethylphenyl)-4,5-dihydro-3(2H)-' pyridazinone~ ~ompound 115) m.p. 142 - 144&.
6-(3-bromophenyl)-4,5-dihydro-3(2H)-pyridazinone, (Compound 117) m.p. 141 - 145C.
6-(4-butyl-3~5-dichlorophenyl)-4,5-dihydro-3(2H)-pyridazinone~ (Compound 100) m.p. 174 - 177C.
6-(3-chloro-4-fluorophenyl)-4,5-dihydro-3(2H)-pyrida~inone, (Compound 139) , ' .
.
.
~ - 55 _ ., . ' .

, . .

.. . . .. . . .

108;~9~

6-(3,5-dichloro-4-isopropylphenyl)-4,5-dihydro-3(2H)-pyridazinone, (Compound 138) m.p. 202 - 205C.
6-(3,4-dibromophenyl)-4,5-dihydro-3(2H)-pyridazinone, (Compound 158) m.p. 181 - 183C.
6-(3-bromo-4-chlorophenyl)-4,5-dihydro-3(2H)-pyridazinone, (Compound 160) m.p. 171 - 173C.
6-(3-bromo-4-fluorophenyl)-4,5-dihydro-3(2H)-pyridazinone, (Compound 161) m.p. 145 - 147C.
6-(4-bromo-3-chlorophenyl)-4~5-dihydro-3(2H)-pyridazinone, (Compound 137) m.p. 170 - 172C.
6-(3,4,5-trichlorophenyl)-4~5-dihydro-3(2H)-pyridazinone, ; (Compound 88) m.p. 195 , 199&.
6-(3,5-dichloro-2-hydroxyphenyl)-4,5-dihydro-3(2H)-pyridazinone~ (Compound 112) m.p. 271 - 273C.

.

1082~90 ~XA~LE 2 Preparation of 6-(3,5-dichloro-4-methylphenyl)-3(2H)-pyridazinone (Compound 7~.
To a suspension of 9.5 g of 6-(3,5-dichloro-4-methylphenyl)-4,5-dihydro-3(2H)-pyridazinone, prepared as described in step (b) of Example 1, in acetic acid at 70& were added drop~Yise, with stirring, 7.2 g of bromine. After completion of the dropwise addition, the resulting mixture was heated under reflux for 1 hour. The mixture was then left overnight and the crystalline substance which separated out was recovered by filtration, washed with cooled ethyl acetate and dried to give the hydrobromide of Compound 7, melting point 258 - 262C (with - decomposition). This hydrobromide was suspended in 50 ml of water and neutralised with concentrated aqueous ammonia. The resulting solid substance was recovered by filtration~ washed with water and dried, to give 9.4 g of Compound 7 as colourless crystals, m.p. 254 - 258C.

Following essentially the same procedure, the following compounds were prepared:
6-(3,4-dichlorophenyl)-3(2H)-pyridazinone, ~Compound 1) m.p. 258 - 262C.
6-(3-chloro-4-methylphenyl)-3(2H)-pyridazinone, (Compound 4) m.p. 275 - 280& .
6-(3-bromo-4-methylphenyl)-3(2H)-pyridazinone, (Compound 5) m.p. 284 - 286C.
6-(3-chloro-4-isopropylphenyl)-3(2H)-pyridazinone~ (Compound 6) m.p. 200 - 204 & .

~ 57 -' ' .. :', : ' , ,. :, - ~ .

6-(3,5-dibromo-4-methylphenyl)-3(2H)-pyridazinone, (Compound 8) m.p. 242 - 246C.
6-(3,5-dichloro-4-ethylphenyl)-3(2H)-pyridazinone~ (Compound 1 10) m.p. 254C.
- 5 6-(3,5-dichloro-4-propylphenyl)-3(2H)-pyridazinone, (Compound 12) m.p. 261&.
6-(3~5-dichloro-2-hydroxy-4-methylphenyl)-3(2H)-pyridazinone~
(Compound 22) ` m.p. abo~e 300C.
t lo 6-(3-chloro-4-ethylphenyl)-3(2H)-pyridazinone, (Compound 29) m.p. 195 - 197 &.
6-(3-bromophenyl)-3(2H)-pyridazinone~ (Compound 31) m.p. 202 - 204C.
6-(3-chlorophenyl)-3(2H)-pyridazinone, (Compound 32) m.p. 227 &.
- 6-(3-chloro-4-methoxyphenyl)-3(2H)-pyridazinone, (Compound 33) m.p. 287 - 288&.
6-(3,4-dichlorophenyl)-3(2H)-pyridazinone-hydrobromide, m.p. 262 - 266&. (dec.) 6-(3-bromo-4-methylphenyl)-3(2H)-pyridazinone-hydrobromide, m.p. 273 - 278 & . (dec.) . ! ' .
6-(3-chlorophenyl)-3(2H)-pyridazinone-hydrobromide~
m.p. 227& . (dec.) 6-(3-bromophenyl)-3(2H)-pyridazinone-hydrobromide~
m.p. 225 - 229& . (dec.) -.' ~

108Z190 1, 6-(3,4-dibromophenyl)-3(2H)-pyridazinone, (Compound 61) m.p. 299 - 303C.
6-(3-chloro-4-fluorophenyl)-3(2H)-pyridazinone, (Compound 62) m.p. 237 - 239C.
6-(3-bromo-4-chlorophenyl)-3(2H)-pyridazinone, (Compound 63) m.p. 289 - 293C.
6-(3-bromo-4-fluorophenyl)-3(2H)-pyridazinone, (Compound 64) m.p. 251 - 253C.
6-(4-bromo-3-chlorophenyl)-3(2H)-pyridazinone, (Compound 51) m.p. 273 - 276&.
6-(3,5-dichloro-4-isopropylphenyl)-3(2H)-pyridazinone, (Compound 52) m.p. 248 - 251C.
6-(3,4,5-trichlorophenyl)-3(2H)-pyridazinone, (Compound 2) m.p. 243 - 246C.
6-(4-butyl-3,5-dichlorophenyl)-3(2H)-pyridazinone, (Compound 14) m.p. 240 - 241C.
6-(3~5-dichloro-2-hydroxyphenyl)-3(2H)-pyridazinone~ (Compound 43) m.p. above 300C.

_ 59 _ EXA~'LE 3 I

Preparation of 6-(3,5-dibromo-2-hydroxy-4-methylphenyl)-3(2H)-pyridazinone (Compound 21).

., (a) 6-(2-hydroxy-4-methylphenyl)-4,5-dihydro-3(2H)-pyridazinone.
S A mixture of 2.08 g of 4-(2-hydroxy-4-methylphenyl)-4- j oxobutyric acid and 0.75 g of hydrazine hydrate in 20 ml of methanol was heated, under reflux, for about 1 hour. After cooling the reaction mixture, the crystalline substance which separated was recovered by filtration and washed with methanol, giving 1.65 g (yield 81%) of 6-(2-hydroxy-4-methylphenyl)-4,5-dihydro-3(2H)-pyridazinone, in the ; form of pale yellow needles melting at 210 - 211C. -. .
Following the same procedure, the following compounds were produced:
6-(4-chloro-2-hydroxyphenyl)-4,5-dihydro-3(2H)-pyridazinone, m.p. 225 - 230C.
6-(5-chloro-2-hydroxy-4-methylphenyl)-4,5-dihydro-3(2H)-pyridazinone~
m.p. above 300C.
6-(5-chloro-2-hydroxyphenyl)-4,5-dihydro-3(2H)-pyridazinone, m.p. 255 - 257Co - . .. . ..

108Zl''~0 (b) Compound 21.

A mixture of 1.0 g of 6-(2-hydroxy-4-methylphenyl)-4,5-dihydro-3(2H)-pyridazinone and 3.0 g of bromine in 10 ml of acetic acid was heated, under reflux, for about 30 minutes. The reaction mixture was cooled and 30 ml of water were added to the cooled mixture;
the crystalline substance which thereby separated was recovered by filtration, washed with water and then with methanol and finally dried, giving 1.65 g (yield 92~o) of the desired product in the form of white crystals having a melting point above 280C.

Following the same procedure, the compounds listed below were also produced: ¦
6-(3,5~ibromo-4-chloro-2-hydroxyphenyl)-3(2H)-pyridazinone, ;
m.p. above 280C.
6-(3-bromo-5-chloro-2-hydroxy-4-methylphenyl)-3(2H)-pyridazinone~ i m.p. above 300C.
6-(3-bromo-5-chloro-2-hydroxyphenyl)-3(2H)-pyridazinone, m.p. above 280&.

Preparation of 6-(5-chloro-2-hydroxy-4-methylphenyl)-4,5-dihydro- -~
3(2H)-pyridazinone (Compound 111).

108219C~ , (~) 4-(5-chloro-2-hydroxy-4-=ethylphenyl)-4-oxobu~yric acid.
10 g of succinic anhydride and 30 g of aluminium chloride `~ were suspended in 100 ml of dichloroethane; 14.2 g of p-chloro-m-cresol were then added dropwise with stirring to this suspension.
After completion of the dropwise addition, the mixture was stirred for 1 hour~ maintaining the temperature of the reaction vessel at ~ -100 - 120& . The reaction mixture was then left to cool, after which a mixture of 200 g of water and 40 ml of concentrated hydrochloric acid was added~ with vigorous stirring. The resulting mixture was allowed to stand and the solid which precipitated was collected by filtration. This solid was repeatedly washed with water until the washings had become neutral. The solid was then dried and recrystal-lised from methanol, giving 9.7 g (yield 40%) of 4-(S-chloro-2-hydroxy-4-methylphenyl)-4-oxobutyric acid, m.p. 181 - 182&.
' - Following the same procedure, the compounds listed below were also prepared:
4-(3,5-dichloro-2-hydroxyphenyl)-4-oxobutyric acid, m.p. 166 - 167C.
4-(4-chloro-2-hydroxyphenyl)-4-oxobutyric acid, m.p. 180 - 181C.
- 4-(5-chloro-2-hydroxyphenyl)-4-oxobutyric acid, m.p. 181 - 182C.
. '.

.

4-(3-chloro-4-methoxyphenyl)-4-oxobutyric acid, m.p. 192 - 198C.
4-(3,4-dichlorophenyl)-4-oxobutyric acid, m.p. 170 - 173&.

(b) Compound 111.
To 70 ml of ethanol were added 7 g of 4-(5-chloro-2-hydroxy-4-methylphenyl)-4-oxobutyric acid, prepared as described above~ and a solution was formed by heating the mixture to about 50C. This solution was then treated as described in step (b) of Example 1, giving 2.4 g of Compound 111, having a melting point above ', ~; ' .
Preparation of 6-(3-bromo-5-chloro-4-methylphenyl)-4,5-dihydro-3(2H)-pyridazinone (Compound 116).
" ' (a) 4-(3-bro -5-chloro-4-methylphenyl)-4-oxobutyric acid.
8 g of aluminium chloride were suspended in 20 ml of dichloroethane, and to this suspension were added, little by little, with stirring at room temperature 4.5 g of 4-(3-chloro-4-methylphenyl)-4-oxobutyric acid. A mixture of 4.2 g of bromine and 5 ml of dichloro-ethane was then added dropwise at room temperature o~er a period of 1 hour to the stirred reaction mixture. The resulting mixture was then "' 10~2190 ~.
stirred for a further 6 hours, allowed to stand overnight~ and then i-~
added to a mixture of 150 g of ice and 25 ml of concentrated hydro-chloric acid. The resulting mixture was then extracted with 300 ml of ethyl acetate, and the extract was repeatedly washed with water and dried over anhydrous sodium sulphate. After evaporating off the solvent, 5.95 g of a residue were obtained. To this residue were added 35 ml of toluene, and the mixture was stirred at 60& for 1 hour; it was then allowed to stand overnight. The crystals which ~
precipitated were collected by filtration, giving 3.9 g of 4-(3-bromo-5-chloro-4-methylphenyl)-4-oxobutyric acid, m.p. 183 - 185C.

(b) Compound 116.
.
10 g of 4-(3-bromo-5-chloro-4-methylphenyl)-4-oxobutyric acid, prepared as described in step (a) above were dissolved in 100 ml of ethanol by adding to the ethanol, with heating. 1.8 g of hydrazine - 15 hydrate were then added dropwise, with stirring at about 50C, to the solution. After completion of the dropwise addition, the reaction mixture was treated as described in step (b) of Example 1, to give 7.4 g of Compound 116, m.p. 199 - 200& .
.

:, Preparation of 6-(3-bromo-5-chloro-4-methylphenyl)-3(2H)-pyridazinone =, . . . .
_Compound 30).

. ~.

': ' ~ ' , ': - -108~90 6.3 g of the 6-(3-bromo-5-chloro-4-methylphenyl)-4,5- ,i dihydro-3(2H)-pyridazinone prepared as described in Example 5 were suspended in acetic acid heated to 70C, and to this suspension were added dropwise with stirring 3.7 g of bromine. After completion of the addition, the reaction mixture was treated as described in Example 2, to give 6.2 g of Compound 30, m.p. 247 - 250 C.
.

Preparation of 6-(3,5-dichloro-4-hydroxyphenyl)-4,5-dihydro-3(2H)-pyridazinone (Compound 112).

.. . .
` 10 (a) 4-(3~5-dichloro-4-hydroxyphenyl)-4-oxobutyric acid.
. _ 32 g of aluminium chloride were suspended in 110 ml of dichloroethane; to this suspension were added, little by little~
with stirring at room temperature 21 g sf 4-(4-methoxyphenyl)-4-oxobutyric acid. Into the resulting mixture over a period of 2 hours were introduced 43 g of chlorine gas, maintaining the temperacure of the mixture at about 40C; this mixture was then stirred at room temperature for 3 hours. When the reaction was complete~ the reaction mixture was treated as described in step (a) of Example 5, giving 15.6 g of 4-(3,5-dichloro-4-hydroxyphenyl)-4-oxobutyric acid~ m.p. 180- 183&.

.
,.

i (b) Compound 112.
To 20 ml of ethanol were added 1.65 g of the 4-(3,5- ¦
dichloro-4-hydroxyphenyl)-4-oxobutyic acid produced in step (a) above, and the mixture was heated at about 50C to dissolve the added acid.
To the stirred solution was added dropwise 0 34 g of hydrazine hydrate and, after the addition was complete, the mixture was treated as described in step (b) of Example 1 to give 1.0 g of Compound 112, m.p. 257 - 263&.
, Preparation of 6-(3,5-dichloro-4-hydroxyphenyl)-3(2H)-pyridazinone ,; , - (Compound 26?.
', 4.3 g of 6-(3,5-dichloro-4-hydroxyphenyl)-4,5-dihydro-3(2H)-pyridazinone (Compound 112), prepared as described in Example 7, were suspended in acetic acid heated to 70& . The resulting suspension was - 15 then treated as described in Example 2, to give 3.7 g of Compound 26 having a meIting point above 300&.
.

Preparation_of 6-(3,5-dichloro-4-methoxyphenyl)-4,5-dihydro-3(2H)-pyridazinone (Compound 120).
. , .

.

(a) Ethyl 4-(3,5-dichloro-4-hydroxyphenyl)-4-oxobutyrate.
4.7 g of 4-(3,5~ichloro-4-hydroxyphenyl)-4-oxobutyric acid (prepared in step (a) of Example 7) were dissolred in 300 ml of absolute ethanol and gaseous hydrogen chloride was passed into the mixture, whilst ice-cooling, for about 30 minutes. When the reaction was complete, the solvent was removed by evaporation and the residue was extracted with benzene. The solrent was then evaporated from the extract, leaving 5.1 g of ethyl 4-(3,5-dichloro-4-hydroxyphenyl)-4-oxobutyrate~ m.p. 117- 119&.

(b) Ethyl 4-(3,5-dichloro-4-methoxyphenyl)-4-oxobutyrate.
A mixture of 2.9 g of the ethyl ester obtained in step (a) above~ 7 g of methyl iodide, 1.4 g of anhydrous potassium carbonate and 20 ml of acetone was stirred at 45 - so& for 3 hours.
At the end of this time, the solvent was removed by evaporation and the residue was extracted with benzene. The extract was washed with 3 water and then the solvent was evaporated from the extract. There were obtained 2.9 g of oily ethyl 4-(3,5-dichloro-4-methoxyphenyl)-4-oxobutyrate (n28 1.5346). On allowing the product to stand at room temperature, it formed crystals melting at 49 - 52C.

(c) Compound 120.
A mixture of 2.45 g of ethyl 4-(3,5-dichloro-4-methoxy-phenyl)-4-oxobutyric acid, prepared in step (b) above, 0.44 g of .

.~ , , :

1~8Zl9O

; hydrazine hydrate and 25 ml of ethanol was refluxed by heating for 13 hours. The reaction mixture was then allowed to cool and the crystals which precipitated were collected by filtration, giving 1.97 g of Compound 120, m.p. 175 - 180C.
.~ ~

Preparation of 6-(3,5-dichloro-4-methoxyphenyl)-3(2H)-pyridazinone (Compound 34).
~, ., -~
1.4 g of the 6-(3,5-dichloro-4-methoxyphenyl)-4,5-dihydro-3(2H)-pyridazinone, Compound 120, prepared in Example 9 were suspended j 10 in acetic acid heated to 70& . The resulting suspension was then ' treated as described in Example 2, giving the hydrobromide of Compound i~ 34, which had a melting point of 245 - 251 & (with decomposition).
From this hydrobromide, proceeding as described ~n Example 2, 1.0 g of Compound 34 was obtained, melting point 245 - 251&.

I 15 i EXAMPLE 11 i Preparation of 6-(4-amino-3-bromophenyl)-4,5-dihydro-3(2H)-pyridazinone ... ..... . _ . _ ................... --tComPound 122).
~, (a) Ethyl 4-(4-amlno-3-bromophenyl)-4-oxobutyrate.
To a suspension of 3.9 g of 4-(4-~m;nophenyl)-4-oxobutyric acid in 150 ml of dichloroethane wer0 added dropwise~ with stirring~ at !

!

-room temperature 6.7 g of bromine; the resulting mixture was allowed to stand overnight and the precipitate which was produced was collected by filtration, washed with ethanol and dissolved, by heating, in ethanol. The ethanol was then evaporated off, giving 3.8 g of ethyl 4-(4-amino-3-bromophenyl)-4-oxobutyrate, m.p. 184 - 186C.

(b) Compound 122.
A mixture of 1.6 g of the ethyl 4-(4-amino-3-bromophenyl)-4-oxobutyrate prepared in step (a) above, 5.5 ml of hydrazine hydrate and 100 ml of ethanol was refluxed with heating for 17 hours. The reaction mixture was then treated as described in step (b) of Example 1 giving 0.8 g of Compound 122, m.p. 224&.
' ' ', -; EXAMPLE 12 -Preparation of 6-(4-amino-3-bromophenyl)-3(2H)-pyridazinone (Compound 36).

0.45 g of 6-(4-amino-3-bromophenyl)-4,5-dihydro-3(2H)-pyridazinone prepared as described in Example 11 was suspended in a 20:5 by volume mixture of water and isopropanol. To the resulting suspension were added 0.45 g of sodium m-nitrobenzenesulphonate and ;~ 0.27 g of sodium hydroxide. This mixture was then refluxed, with heating, for 3.5 hours and then allowed to stand and cool. The mixture was then neutralised by the addition of 6 N hydrochloric acid, ; and the yellow crystals which precipitated were collected by .

' .

. . ' ' . ~
.

filtration. These crystals were recrystallised from a mixture of ethanol and acetone, giving 0.4 g of Compound 36, m.p. 266 - 267&.
.' I

Preparation of 6-(4-amino-3,5-dibromophenyl)-3(2H)-pyridazinone (Compound 37).

~ To a suspension of 1.2 g of 6-(4-aminophenyl)-3(2H)-- pyridazinone in 50 ml of dichloroethane were added dropwise at room temperature 2.3 g of bromine. When the dropwise addition was complete, the mixture was refluxed by heating for 14 hours. It was then allowed to cool, after which the solvent was evaporated off under reduced pressure. The resulting residue was recrystallised from ethanol, giving 1.9 g (yield 86%) of Compound 37, m.p. 276 - 278C

,~.
Preparation of 6-(4-amino-3-chlorophenyl)-4,5-dihydro-3(2H)-pyridazinone (Compound 121).

(a) 4-(4-acetamido-3-chlorophenyl)-4-oxobutyric acid.
To a stirred solution of 2.35 g of 4-(4-acetamidophenyl)-4-oxobutyric acid in 100 ml of dichloroethane were added, at room temperature~ 5.3 g of aluminium chloride; the resulting mixture was stirred at 50C for S hours. Into the mixture were introduced 1.56 g . , .

1082~90 of chlorine gas, with ice-cooling, and the mixture was then stirred ~Z
overnight at room temperature. A further 1.56 g of gaseous chlorine were then introduced into the mixture, after which it was stirred at 50 - 55& for 2 hours. -It was then allowed to cool, poured into 600 ml of ice-water and extracted with diethyl ether. The extract was washed with water until the washings had become neutral. The washed extract was then dried over anhydrous sodium sulphate and the solvent was evaporated off, leaving 0.9 g (yield 32%) of 4-(4-acetamido-3-chlorophenyl)-4-oxobutyric acid, m.p. 168 - 170C.
` , . .
(b) Compound 121.

A mixture of 1 g of 4-(4-acetamido-3-chlorophenyl)-4-oxobutyric acid, prepared as described in step (a) above,and 40 ml of 18% aqueous hydrochloric acid was refluxed by heating for 1.5 hours.
The resulting mixture was then allowed to cool, after which it was added to aqueous ammonia to give a mixture having a pH of about 4.5.
!
The crystals which precipitated were collected by filtration and dissolved in a mixture of acetone and ethanol, insoluble materials !
being removed. The solvent was evaporated from the resulting solution, and the residue was dissolved in 10 ml of ethanol. 0.2 ml of hydrazine hydrate were added to the solution, which was then stirred at room temperature for 6.5 hours. At the end of this time, the crystals which ; had precipitated were collected by filtration, giving 0.6 g of Compound 121~ m.p. 238 - 239& .
.'' , .
- 71 ~

. ~
- . .
. .

108Zl90 i Preparation of 6-(4-amino-3-chlorophenyl)-3(2H)-pyridazinone (Compound 35).

!
` 0.34 g of the 6-(4-amino-3-chlorophenyl)-4,5-dihydro-3(2H)-pyridazinone, Compound 121, prepared in Example 14 was suspended in a 20:5 by volume mixture of water and isopropanol. The resulting suspension was then treated as described in Example 12, giving 0.18 g of Compound 35 melting point 280 - 2820C
. ' . ~ .

. .

Preparation of 6-(4-allyloxy-3,5-dichlorophenyl)-4,5-dihydro-3(2H)-~ pyridazinone (Compound 146).

! 5 g of 6-(3,5-dichloro-4-hydroxyphenyl)-4,5-dihydro-3(2H)-pyridazinone~ Compound 112, prepared as described in step (b) of Example 7 and 3.3 g of anhydrous potassium carbonate were mixed with 50 ml of acetone, and 2.4 g of allyl bromide were added dropwise, at . room temperature, to the resulting mixture, with stirring. When the dropwise addition was complete, the mixture was heated under reflux for 4 hours. It was then cooled and filtered; the filtrate was con-centrated by evaporation under reduced pressure and the residue was recrystallised from ethanol, giving 5.3 g (yield 93%) of Compound 146, m.p. 137C.

', ' .
.. . . .

108Zl90 Following the same procedure, the following compounds were also produced:
6-~ ,5-dichloro~4-(2-propynyloxy)pheny~ -4,5-dihydro-3(2H)-pyridazinone (Compound 148), m.p. 198 - 201C.
6-(3,5-dichloro-4-propoxyphenyl)-4,5-dihydro-3(2H)-pyridazinone (Compound 147), m.p. 149 - 151C.
..

~ .
Preparation of 6-(4-allyloxy-3,5-dichlorophenyl)-3(2H)-pyridazinone ~; (Compound 75).
!
To a mixture of 4.9 g of 6-(3,5-dichloro-4-hydroxyphenyl)-3(2H)-pyridazinone (Compound 26), prepared as described in Example 8, and 2.0 g of triethylamine in 30 ml of dimethylformamide were added dropwise 2.4 g of allyl bromide at 50& ~ with stirring. The mixture was stirred at so& for a further 5 hours, after ~hich it was cooled.
After cooling, the reaction mixture was poured into 200 ml of water and allowed to stand. The white solid substance which formed was recovered by filtration, washed with water and dried, giving 3.6 g of a crude crystalline substance. This crude crystalline substance was recrystallised from methanol, giving 3.2 g of Compound 75 in the form of colourless needles melting at 214 - 215C.

Following the same procedure, 6-~ ,5-dichloro-4-(2-propynyl-oxy)phenyy -3(2H)-pyridazinone (Compound 76)~ melting point 240C, was also prepared.

108~z190 Preparation of 6-(2-acetoxy-3,5~ibromo-4-methylphenyl)-3(2H)-pyridazinone (Compound 78).

A mixture of 1.0 g of 6-(3,5~ibromo-2-hydroxy-4-methylphenyl)-3(2H)-pyridazinone and 2 ml of acetic anhydride in 10 ml of benzene was heated under reflux for 3 hours and then cooled. After cooling, the crystalline substance which separated was recovered by filtration and dried, giving o.8 g (yield 71.5%) of Compound 78 in the form of yellow ; needles melting at 220&.

'I
Following the same procedure, 6-(2-acetoxy-3-bromo-5-chloro-4-methylphenyl)-3(2H)-pyridazinone (Compound 79), m.p. 215- 220C~ was also prepared.

.
Preparation of 6-(3,5-dichloro-4-p-toluenesulphonyloxyphenyl)-4,5-dihydro-3(2H)-pyridazinone (Compound 152).

A mixture of 10 g of 6-(3,5-dichloro-4-hydroxyphenyl)-4,5-dihydro-3(2H)-pyridazinone~ 7.6 g of ~toluenesulphonyl chloride, 4.0 g of triethylamine and 50 ml of dimethylformamide was stirred at 50C for 8 hours. The reaction mixture was then treated as described in Example 17 and recrystallised from a mixture of dioxan and petroleum ether, - gi~ g 3.8 g of Compound 152 in the form of prisms melting at 208 - 209&.

, . . . : : . .
:, . . . .. ..

1082~90 Following the same procedure, the following compounds were prepared: ¦
6-(3,5-dichloro-4-~toluenesulphonyloxyphenyl)-3(2H)-pyridazinone (Compound 83), m.p. 254 - 256C.
6-(4-acetoxy-3,5-dichlorophenyl)-3(2H)-pyridazinone (Compound 82), m.p. 258 - 260C.
!

.' I .
Preparation of potassium salt of 6-(3,4-dichlorophenyl)-3(2H)-pyridazinone.

To a solution of 0.22 g of potassium hydroxide in 5 ml of I methanol was added 0.96 g of 6-(3,4-dichlorophenyl)-3(2H)-pyridazinone (Compound 1), and the resulting mixture was stirred at room temperature for about 30 minutes. After completion of the reaction, a small quantity of insolubles was filtered off and the filtrate was concentrated.
A small quantity of ethanol was added to the resulting residue and the mixture was then evaporated to dryness. This procedure was repeated twice~ to give the desired product in its hydrate form as a colourless solid having a melting point above 280&.

Following the same procedure, the following compounds were also prepared:
, ~ 75 --Potassiwn salt of 6-(3,5-dichloro-4-methylphenyl)-3{2H)-pyridazinone, m.p. above 280C.
Potassium salt of 6-(3,5-dichloro-4-ethylphenyl)-3(2H)-pyridazinone~ m.p. above 280&.
S Potassium salt of 6-(3,5-dichloro-4-methoxyphenyl)-3(2H)-pyridazinone, m.p. above 280C.

, .
~ Preparation of calcium salt of 6-(3,4-dichlorophenyl)-3(2H)-pyridazinone.

- To a solution of 0.1 g of calcium chloride in 5 ml of water was added 0.5 g of the potassium salt of 6-(3~4-dichlorophenyl)-3(2H)-pyridazinone~ prepared as described in Example 20, and the resulting mixture was stirred at room temperature for about 30 minutes. At the end of this time, the solid product thus obtained was recovered by filtration, washed with water and then dried, gi~ing the desired product in its hydrate form having a melting point above 280&.

Following the same procedure~ the compounds listed below were also produced:
` Calcium salt of 6-(3,5-dichloro-4~ethylphenyl)-3(2H)-pyridazinone, m.p. above 280&.
Calcium salt of 6-(3~5-dichloro-4-ethylphenyl)-3(2H)-pyridazinone~ m.p. above 280&.

- 76 - - t , 108Z~90 I

Calcium salt of 6-(3-chloro-4~isopropylphenyl)-3(2H)-pyridazinone, m.p. above 280C.
Calcium salt of 6-(3,5-dichloro-4-methoxyphenyl)-3(2H)-pyridazinoneJ m.p. above 280&.

1, .

` Preparation of sodium salt of 6-(3,5-dichloro-4-methylphenyl)-3(2H)- ~j .
pyridazinone.
-To a solution of 0.16 g of sodiu~ hydroxide in 5 ml of ., methanol was added 1 g of 6-(3,5-dichloro-4-methylphenyl)-3(2H)-pyridazinone (Compound 7), and the resulting mixture was stirred at room temperature for about 30 minutes. At the end of this time~ the ii ~, reaction mixture was treated and purified as described in Example 20, giving the desired product in its hydrate form as a colourless solid having a melting point above 280&.

: .Following the same procedure, the sodium salt of 6-(3,5- -dichloro-4-methoxyphenyl)-3(2H)-pyridazinone, m.p. above 280&, was also produced.
., .

, .
Preparation of 6-(3,5-dichloro-4-methylphenyl)-3(2H)-pyridazinone , methyl isocyanate adduct.

- 77 ~

.

To a hot solution of 1.0 g of 6-(3~5-dichloro-4-methylphenyl)-3(2H)-pyridazinone in 25 ml of dioxan was added methyl isocyanate in molar excess (above 0.5 ml); the mixture was allowed to stand in a sealed vessel at room temperature for 3 hours. 5 ml of hexane were then added and the resulting mixture was cooled, giving 1.0 g (yield 82%) of the desired product as needles, melting at about 250C (with decomposition).

Following the same procedure~ the compounds listed below were also prepared: 5 - 10 6-(3~4-dichlorophenyl)-3(2H)-pyridazinone methyl isocyanate adduct, m.p. about 263 - 264 & (with decomposition).
6-(3-chloro-4-methylphenyl)-3(2H)-pyridazinone methyl isocyanate adduct, m.p. about 270C (with decomposition). I
6-(3-bromo-4-methylphenyl)-3(2H)-pyridazinone methyl isocyanate ~; 15 adduct, m.p. about 270& (with decomposition).
6-(3~5-dichloro-4-hydroxyphenyl)-3(2H)-pyridazinone methyl isocyanate adduct, m.p. above 300& (with decomposition).
~,:
- The following Examples 24, 25 and 26 illustrate the preparation of agricultural fungicidal compositions according to the invention and all parts are by weight.

. .

', , .. . . . .

.

Dusts.

5 parts of Compound 34, 50 parts of talc and 45 parts of kaolin were uniformly mixed to form a dust.

EXAMPLE 25 ~
., Wettable powder.
__ 50 parts of Compound 7, 29 parts of clay, 10 parts of diatomaceous earth, 5 parts of white carbon, 3 parts of sodium ligno-sulphonate, 2 parts of Newcoal 1106 (a trade name of Nihon Nyukazai K.K., Japan) and 1 part of polyvinyl alcohol were uniformly mixed in a mixer and pulverised 3 times using a hammer mill, to give a wettable powder.

Granules.
., .-70 parts of Compound 1 were finely pulverised, and 30 parts of clay were added thereto; they were then mixed in a mhxer to fonm a premix. 10 parts of this premix were uniformly mixed with 60 parts of clay and 30 parts of bentonite in a mIxer. The mixture was then kneaded with a suitable amount of water in a kneader, extruded through a screen having apertures of diameter 0.8 mm and dried in a draught drier at 50C.
The resulting product was formed into granules by means of a sifter.

The following Examples 27 to 30 illustrate the use of the fungicidal compositions of the present invention. The wettable powders employed were prepared by the procedure described in foregoing Example 25 and each contained 50% by weight of the respective compound of the present invention.
~ ' :

Preventive and curative effect against damping-off on cucumbers ., ._ The pathogenic fungus of damping-off (Rhizoctonia sola_ ) was incubated on rice bran at 28& for 2 weeks and then homogeneously mixed with soil. The soil was placed in a pot having a diameter of 12 cm and 20 cucumber seeds of the variety Sagamihanpaku were sown thereon. A test preparation containing one of the active compounds listed in following Table 1 was then poured in an amount of 25 ppm onto the plant at the rate of 3 litres per square metre. The resulting - pots were kept in a greenhouse at 25& for 2 weeks, after which the - 20 number of infected seedlings was determined. The results are summarised in Table 1.

108Z ~90 Table 1 .
Infected Infected : Compd. No. seedlings Compd. No. seedlings (number) . (number) . hydrobromide of 1 3 33 12 potassium salt of 1 2 34 0 calcium salt of 1 2 hydrobromide of 34 0 4 7 potassium salt of 34 1 sodium salt of 34 0 hydrobromide of 5 6 calcium salt of 34 0 ~' 6 5 35 13 , 7 0 36 8 .` hydrobromide of 7 0 37 6 potassium salt of 7 0 39 10 sodium salt of 7 0 mixture of 4 and 7 2 calcium salt of 7 0 62 4 ~i , 8 2 87 10 `~ 10 3 90 14 potassium salt oflO 4 91 6 calcium salt of 10 5 92 9 t 12 13 94 6 . 20 4 96 10 ,~ 21 0 115 13 : 30 4 . 139 17 31 11 l Untreated control 59 : - 81 -.

EXA~PL~ 28 Control of sheath blight on rice plants (preventive effect).

Rice plant seedlings of the variety Koganenishiki at the 4 - 5 leaf stage were sprayed with a test preparation at 30 ppm S in a total amount of 50 ml per 3 pots. The host plants were left at room temperature for 24 hours and then 4 - 5 oat grains, on which the pathogenic fungus of sheath bl;ght (Pellicularia sasakii) had previously been incubated, were placed around the root of each rice plant. The plants were then placed in a greenhouse at 25 - 27&
and 10 days after introduction of the fungus were examined for the degree of damage by determining the height of each diseased spot in centimetres. The results are shown in Table 2.

.
' .

:, . : :.
.

10~2190 Table 2 Hei ght of Hei ght of Compd. No. diseased Compd. No. diseased spot (cm) spot (cm) . 1 0 ~ 35 2.0 hydrobromide of 1 0.4 36 2.3 potassium salt of 1 0.5 37 1.2 calcium salt of 1 0.4 39 0.7 :
2 0.5mixture of 4 and 7 0.9 . 4 1.2 (1:1) 0.4 87 0.9 .
hydrobromide of 5 0.6 90 1.5 :
6 0.9 91 1.2 7 0 92 1.7 hydrobromide of 7 0 93 0.4 potassium salt of 7 0 94 0.8 sodium salt of 7 0 96 2.0 :.
calcium salt of 7 0 116 0.8 8 0 117 1.7 ~' 10 0.4 118 1.9 -:
potassium salt of 10 0.5 120 0.2 : ~
calcium salt of 10 0.9 128 2.0 ~: :
0.6 129 3.1 :`
21 0.1 139 3.0 22 2.9 146 1.9 26 1.9 61 0.9 28 0.5 62 0.2 . 29 1.8 63 0.8 : 30 0 64 0.7 31 1.3 52 0.6 32 1.3 66 0.1 33 1.6 67 0.1 34 0 68 0.7 hydrobromide of 34 0 69 0.7 potassium salt of 34 0 70 2.1 sodium salt of 34 0.2 71 2.3 . .
calcium salt of 34 O 88 2.0 . _ Untreated control14.2 . ~

. , . .:
, . . .: .

~0821~0 I

Control of sheath blight in rice plants (curative effect).

Rice plant seedlings of the variety Koganenishiki at the 6 - 7 leaf stage were infected with sheath blight by placing around S the roots of each seedling 4 - 5 oat grains on which the pathogenic fungus of rice sheath blight (PeIlicularia sasakii) had previously been incubated. The host plants were placed in a greenhouse at 25 -27&. 3 days after the inoculation (by which time the height of the diseased area was 1.8 - 2.0 cm), the host plants were removed from the greenhouse and sprayed with each test preparation at 100 ppm in a total amount of 50 ml per 3 pots. The plants were air-dried and then again placed in the greenhouse at 25 - 27& . 10 days after the application~ the degree of disease was investigated by determining the height of the diseased spot (in centimetres). The results obtained are shown in Table 3.

~ .
`
'~
.~ ' - , ~ . .

.,., ,. : , ' - - . - . - :, ,,,:

~ 108Zl90 Table 3 :
l . "
Height of l Height of Compd. No. diseased ¦ Compd. No. diseased . spot (cm) l spot (cm) 1 0.9 1 32 3.2 i hydrobromide of l 1.0 ¦ 33 3.1 potassium salt of 1 1.0 ¦ 34 0.5 calcium salt of 1 1.2 ¦ hydrobromide of 34 0.5 4 2.3 ¦ potassium salt of 34 0.6 . 5 1.0 ¦ sodium salt of 34 0.6 hydrobromide of 5 1.2 ¦ calcium salt of 34 0.6 6 1.9 1 35 4.1 7 0.3 1 36 4.2 ~' hydrobromide of 7 0.3 ¦ 37 1.9potassium salt of 7 0.4 ¦ 39 0.9 sodium salt of 7 0.4 ¦ mixture of 4 and 7 1.5 calcium salt of 7 0.4 ¦ 87 1.4 ~ 8 0.3 1 . 90 2.9 :~. 10 1.2 1 91 2.3 potassium salt of 10 1.2 1 92 3.1 : calcium salt of 10 1.3 ¦ 93 0.8 ,. 20 1.7 1 94 1.2 .. 21 1.8 1 96 3.5 . 22 4.1 1 116 1.5 ~J''~ 26 2.2 1 117 3.0 28 1.0 1 118 3.2 . 29 2.4 1 120 0.9 .i. 30 0.3 1 128 3.5 ~` 31 2.9 146 3.1 ¦ ¦ Untreated control ¦ 15.6 : ' ' ' ~'' '' ~ :

: - 85 - :
:,,,, . . :
..
.,: . - ~ , ' . '....... . : .
::, ...... . , : : ':
: .

~08Z190 ., Curative effect against sheath blight of rice plants.

Rice plant seedlings of the variety Koganenishiki at the 4 - 5 leaf stage were infected with sheath blight by placing around the roots of each seedling 4 - 5 oat grains on which the pathogenic fungus of rice sheath blight (Pellicularia sasakii) had previously been incubated.
The host plants were placed in a greenhouse at 25 - 27C. 2 days after the inoculation (at which time the height of the diseased area was 1.8 -2.0 cm), the host plants were removed from the greenhouse and sprayed with each test preparation at 100 ppm in a total amount of 50 ml per 3 pots. The plants were then air-dried, after which they were again placed in the greenhouse at 25 - 27&. 8 days after the application, the degree of disease was investigated by determining the height of the diseased spot. The results are shown in Table 4.

-. . - - . , . : -: - -- Table 4 .Height of Height Oe Compd. No. diseased Compd. No.diseased spot (cm) . spot (cm) 1 1.9 sodium salt of 72.1 hydrobromide of 1 2.0 calcium salt of 7 2.2 potassium salt of 1 2.1 10 2.0 calcium salt of 1 2.5 potassium salt of 10 1.9 4 4.2 calcium salt of 10 1.9 hydrobromide of 7 1 9 . Untreated control 11.7 potassium salt of 7 2.0 ~

It will be apparent from the results achieved in Examples 27 to 30 that the pyridazinone derivatives of the present invention have remarkably good fungicidal activity against various pathogenic fungi.

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, .

Claims (8)

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A pyridazinone derivative of the formula (II') (I) [in which R1 represents a hydrogen atom, a hydroxy group, a group of formula -O-CO-R5 (in which R5 represents an alkyl group having from 1 to 5 carbon atoms) or a group of formula -O-SO2-R6 (in which R6 represents a phenyl group which is unsub-stituted or has one or more halogen or C1-3 alkyl substituents);
R2 and R4 are the same or different and each represents a halogen atom, or one of R2 and R4 represents a halogen atom and the other represents a hydrogen atom;
R3 represents a hydrogen atom, an alkyl group having from 1 to 6 carbon atoms, an alkoxy group having from 1 to 6 carbon atoms, an alkenyloxy group having from 3 to 5 carbon atoms, an alkynyloxy group having 3 or 4 carbon atoms, an amino group, a hydroxy group, a halogen atom, a group of formula -O-CO-R5 (in which R5 is as defined above) or a group of formula -O-SO2-R6 (in which R6 is as defined above), provided that, when R3 represents a halogen atom, a hydroxy group or said alkoxy group, both R2 and R4 represent halogen atoms; and A represents the group -CH2-CH2- or -CH=CH-]
or, when A represents the group -CH=CH, a salt thereof.

2. Compounds according to claim 1, selected from the group consisting of:
6-(3-chloro-4-methylphenyl)-3(2H)-pyridazinone, 6-(3-bromo-4-methylphenyl)-3(2H)-pyridazinone, 6-(3-chloro-4-isopropylphenyl)-3(2H)-pyridazinone, 6-(3,5-dichloro-4-methylphenyl)-3(2H)-pyridazinone, 6-(3,5-dibromo-4-methylphenyl)-3(2H)-pyridazinone, 6-(3,5-dichloro-4-ethylphenyl)-3(2H)-pyridazinone, 6-(3,5-dibromo-4-chloro-2-hydroxyphenyl)-3(2H)-pyridazinone, 6 -(3,5-dibromo-2-hydroxy-4-methylphenyl)- 3(2H)-pyridazinone, 6-(3-bromo-5-chloro-2-hydroxy-4-methylphenyl)-3(2H)-pyridazinone, 6-(3-bromo-5-chloro-4-methylphenyl)-3(2H). pyridazinone, 6-(3-bromophenyl)-3(2H)-pyridazinone, 6 (3-chlorophenyl)-3(2H)-pyridazinone, 6-(3,5-dichloro-4-methoxyphenyl)-3(2H)-pyridazinone, 6-(4-amino-3,5-dibromophenyl)-3(2H)-pyridazinone, 6-(3,5-dichloro-4-methylphenyl)-3(2H)-pyridazinone methylisocyanate, 6-(3-bromophenyl)-4,5-dihydro-3(2H)-pyridazinone and 6-(3,5-dichloro-4-methoxyphenyl)-4,5-dihydro-3(2H)-pyridazinone.

3. A process for preparing a pyridazinone derivative of formula (II') or salt thereof, as defined in claim 1, which comprises the steps:

A (a) reacting a compound of formula (VI - 1):

in which R1, R2, R3 and R4 are as defined above or a compound of formula (VI - 2):

(in which R1 and R3 are as defined above and R2a and R4a each represent hydrogen atoms or one of R2a and R4a represents a hydrogen atom and the other represents a halogen atom) with succinic anhydride, in the presence of a Lewis acid, to prepare a substituted benzoylpropionic acid;
A (b) reacting said substituted benzoylpropionic acid with hydrazine to prepare a compound of formula (IV - 1) or (IV - 2):

or A (c) if necessary, dehydrogenating or halogenating and dehydrogenating said compound (IV - 1) or (IV - 2) to produce a compound of formula (III):

A (d) if necessary, salifying the compound of formula (III);
or, where R3 is an amino group, B (a) reacting a compound of formula (VI - 3):

(in which R9 represents a lower alkyl group) with succinic anhydride to produce a substituted benzoylpropionic acid;
B (b) in any order, deacylating, halogenating and reacting with hydrazine said substituted benzoylpripionic acid;
B (c) if necessary, dehydrogenating the product of halogenation, deacylation or reaction with hydrazine; and B (d) if necessary, salifying the resulting compound; or, where R3 is an alkoxy group with 1 to 6 carbon atoms, C (a) halogenating a compound of formula (V - 7):

(in which R3a is as defined above, R2a and R4a each represent hydrogen atoms or one of R2a and R4a represents a hydrogen atom and the other represents a halogen atom, and R is as defined above), C (b) reacting the product of step C (a) with hydrazine;
C (c) if necessary, dehydrogenating the product of step C (b);
and C (d) if necessary, salifying the resulting product, or, where R1 is hydrogen and R3 is an alkoxy group, an alkenyloxy group or an alkynyloxy group, D (a) in any order, reacting a compound of formula (V - 9):

(in which R2 and R4 are as defined and R10 represents a hydrogen atom or an alkyl group) with hydrazine and with an alkylating, alkenylating agent;
D (b) if necessary, after reaction with said hydrazine and/or said alkylating, alkenylating or alkynylating agent, dehydrogenating the reaction product; and D (c) if necessary, salifying the resulting product.

4. A process according to claim 3, which comprises the additional step of reacting a compound wherein R1 represents a hydroxy group and R3 represents a hydrogen atom, said alkyl group, said alkoxy group, said alkenyloxy group, said alkynyloxy group or a halogen atom with a compound of formula R5 COX or R6SO2Y (in which X represents a halogen atom or the group -O-CO-R5, R5 being as defined in claim 1, and Y represents a halogen atom) to produce a compound of formula (I) wherein R1 represents the group -O-CO-R5 or -O-SO-R6.

5. A process according to claim 3, which comprises the additional step of reacting the resulting compound wherein R3 represents a hydroxyl group and R1 represents a hydrogen atom with a compound of formula R5 COX or R6SO2Y (in which X represents a halogen atom or the group -O-CO-R5, Y represents a halogen atom and R5 and R6 are as defined in claim 1) to produce a compound of formula (I), wherein R3 represents the group -O-CO-R5 or -O-SO2-R6.

6. A process for preparing a pyridazinone derivative of formula (III) or a salt thereof, as defined in claim 3, which comprises dehydrogenating a compound of formula (IV - 1) (in which R1, R2, R3 and R4 are as defined above), and optionally thereafter salifying said compound of formula (III) to produce a salt thereof.

7, A process as claimed in claim 6, wherein:
R3 represents a hydrogen atom, a methyl group, an ethyl group, an amino group, a methoxy group, an ethoxy group or an alkenyloxy group having 3 or 4 carbon atoms; and R2 and R4 are the same or different and each represents a chlorine atom, a fluorine atom or a bromine atom.

8. A process as claimed in claim 6 or claim 7, which comprises the additional step of reacting a compound of formula (III) in which R3 represents a hydroxy group with a compound of formula R5COX
or R6SO2Y [in which:
X represents a halogen atom or the group -O-CO-R5;
Y represents a halogen atom;
R5 represents an alkyl group having from 1 to 5 carbon atoms;
and R6 represents a phenyl group which is unsubstituted or has one or more halogen or C1 - C3 alkyl substituents] to produce a compound of formula (III) wherein R is replaced by a group of formula O-CO-R5 or -O-SO2-R6.