CA1111434A

CA1111434A - Preparation of insecticides and acaricides

Info

Publication number: CA1111434A
Application number: CA297,256A
Authority: CA
Inventors: Gerald Berkelhammer; Venkataraman Kameswaran
Original assignee: American Cyanamid Co
Current assignee: Wyeth Holdings LLC
Priority date: 1977-03-03
Filing date: 1978-02-17
Publication date: 1981-10-27
Also published as: FR2401149A1; DE2808627A1; AU515201B2; BR7801203A; AU3304178A; FR2395267A1; IT7848222A0; AU3301478A; IT1102399B; FR2401149B3; IL53946A0; JPS53124269A; AR219311A1

Abstract

ABSTRACT

The invention is novel m-phenoxybenzyl esters of .2,2-difluoro-1,3-benzodioxole-5-(a-alkyl)acetic acids, preparation thereof, and methods of use of the compounds for the control of insects and acarids.

Description

26,573 1 The art discloses in South African Patent Appli-cation No. 73/4462, assigned to Sumitomo Chemical Co. Ltd.
literally tens of thousands of phenylacetic acid esters including 3'-phenoxybenzyl-~-isopropyl-4-methoxyphenylacetate;
3'-phenoxybenzyl-~-isopropyl-3-methoxyphenylacetate; 3'-phenoxybenzyl-~-isopropyl-4-chlorophenylacetate; 3'-phenoxy-benzyl-~-isopropyl-4-methylphenylacetate; 3'-phenoxybenzyl-~-isopropyl-3-chlorophenylacetate and 3'-phenoxybenzyl-a-isopropyl-4-fluorophenylacetate. They indicate that many of their compounds are effective pesticidal agents and useful for the control of a variety of insects and mites. The applicants do not, however, describe the m-phenoxybenzyl esters of 2,2-difluoro-1,3-benzodioxole-5-(~-alkyl)acetic acids which are the subject of the present invention; nor do they provide a synthesis applicable to the preparation of the compounds.
Surprisingly, we have found that the compounds of the present invention are not only effective insecticidal agents but are also highly effective ixodicidal agents.
; The compounds have a high margin of safety and can be used ; 20 effectively to protect domestic, laboratory and farm animals from attack by insects and ticks. The compounds of this invention also exhibit residual ixodicidal and insecticidal - activity, and are outstandingly effective for control of tobacco budworm and mosquitoes.
The invention is m-phenoxybenzyl esters of 2,2-difluoro-1,3-benzodioxole-5-(~-alkyl)acetic acids represented by the formula:

F X ~ CH-COOCH ~
:

1~11434 wherein Rl is ethyl, _-propyl or ~-propyl; R2 is hydrogen or cyano, including the optical isomers thereof. The invention is also a method for controlling :insects and acarina by contacting the insects and acarina, their habitat, breeding grounds and/or their food supply, with an insecticidally or acaricidally effective amount of a m-phenoxybenzyl ester of a 2,2-difluoro-1,3-benzodioxole-5-(a-alkyl)acetic acid. The invention includes a method for protecting agronomic crops, either growing or harvested, and homothermic animals from 10 attack by insects and/or acarina by treating the crops and/oranimals with an insecticidally or acaricidally effective amount of the above-identified m-phenoxybenzyl ester of a

2,2-difluoro-1,3-benzodioxole-5-(a-alkyl)acetic acid. The invention further includes the novel acids of the formula:
O

FX~ Rl :: wherein Rl is lower alkyl and Y is hydroxyl or halogen, and the optical isomers thereof and a method of preparing these acids which are useful in preparing the pesticidal esters of the invention.
Advantageously, the m-phenoxybenzyl esters of ., the 1,3-benzodioxole-5-acetic acid can be prepared by reactinga 2,2-difluoro-1,3-benzodioxole-5-(a-alkyl)acetic acid halide (II), preferably chloride, with a m-phenoxybenzyl alcohol (III). The reaction is generally conducted in the presence of solvent such as diethyl ether, benzene, or toluene, at a temperature between about 10C and 30C in the presence of ` " 1~11434 ;
. an acid acceptor. Among the acid acceptors that can be . employed are the tertiary organic amines, trimethylamine, triethylamine and pyridine. This rcaction can be illustrated - as fol lows:

:- O
X ~ CH-C-X HOCH ~ O

: (II) (III) :, ..'.
F~ < ~ ~ CH-CO -O-CH ~ O

'~, :' (1) wherein R] is ethyl, n-propyl or i-propyl; R2 is H or CN
and X is halogen, preferably chlorine.
.~ Preferred compounds within the generic formula I
~ depicted above, are those wherein Rl is isopropyl and R2 -.~: 10 is hydrogen or cyano.
- With regard to the compounds of the present in-~ vention as depicted by formula I, it should also be under-.~ stood that various optical isomers of the above-identified ~ compounds do result from the preparations described.
- For example, in the synthesis of formula I esters, wherein R2 is hydrogen, a chiral center is present at Rl and d and 1 isomeric pairs are formed. Also, ~-cyano substitu-tion at R2 introduces an additional chiral center thus allowing for an additional d, 1 pair.
The 2,2-difluoro-1,3-benzodioxole-5-(~-alkyl)acetyl-halide (II), can be prepared by using 5-methyl-1,3-benzodioxole (X) as a starting material. The process for the preparation .~ , 1 involves 8 steps, the first of which is the halogenation of the 5-methyl-1,3-benzodioxole (X) with a halogenating agent, such as phosphorus pentachloride in the presence of an inert solvent such as toluene to yield the corresponding 2,2-di-chloro-5-methyl-1,3-benzodioxole (IX). This compound (IX) is then converted to the corresponding 2,2-difluoro-5-methyl-1,3-benzodioxole (VIII) with antimony (III) fluoride in an inert solvent such as dioxane. Next, the thus obtained 2,2-difluoro-5-methyl-1,3-benzodioxole (VIII) is converted to the corresponding 5-halomethyl derivative by halogenation with bromine, chlorine, N-bromosuccinimide and the like.
This reaction is preferably conducted in the presence of an inert solvent such as carbon tetrachloride, and a radical ;~ ~
initiator such as light, benzoyl peroxide, or azo-bis-iso-butyronitrile to yield 2,2-difluoro-5-halomethyl-1,3-benzo-dioxole (VII). The formula (VII) compound is then readily ; converted to the corresponding acetonitrile (VI) by reaction with sodium or potassium cyanide in the presence of dimethyl-sulfoxide (DMSO), ethanol or the like at an elevated tem-perature. This acetonitrile (VI) is readily alkylated when -~ treated with an alkyl halide, alkyl sulfate, or alkyl sul-fonate in the presence of a base and an inert solvent. Crown ethers have been found to be useful catalysts in this reaction.
The a-alkylacetonitrile formed in the above reaction is de-picted by formula (V) and hydrolysis of formula (V) a-alkyl-acetonitrile, using an alkali metal hydroxide in the presence of an alkylene glycol and water, yields the a-alkyl acetic acid shown as formula (IV). Treatment of the formula (IV) acid with thionyl chloride, thionyl bromide or the like, pre-ferably in the presence of an aromatic solvent such as benzene 1 or toluene, then yields 2,2-difluoro-1,3-benzodioxole-5-(a-alkyl)acetyl halide (II) which is then reacted with the :` m-phenoxybenzyl alcohol (III) to yield the desired m-phenoxy--. benzyl ester or a-cyano-m-phenoxybenzyl ester of 2,2-di-fluoro-1,3-benzodioxo-5-(a-alkyl)acetic acid (I).
These reactions are graphically illustrated in Flow Diagram I below.
Flow Diagram I

.-~ / ~ CH3 PC15 ~ ~ ~ CH3 ~ ~ toluene, -~ (X) (IX) '''' .

X ~ CH3 SbF3 ~ ~ C~13 Cl 0~ ~ dioxane,~
:~ 15 (IX) (VIII) ' F ~ ~ CH3 NPC X ~ CH2Br (VIII) (VII) FX~ H2BrNacN ~ X~ CH2-CN
: F 0 ~ EtOH/H2O,~
(VII) (VI) F\ /0 ~ CH2-CN Rl-X
F ~ ~ Dicyclohexyl-13-crown-6 o benzene, 50% NaOH

X ~ CH-CN

V

1~1434 ;. wherein Rl is ethyl, _-propyl or i-propyl and X is chloride, bromideJ iodide, Cl-C4 alkyl sulfateJ benzenesulfonateJ or p-toluenesulfonate.
Flow Diagram I - continued F ~ ~ Rl ethylene glycol ~V) F O ~ CH-COOH

;. (IV) : O ,, '................... F ~ CH-COOH SOC12 ~ ~ CH-C-Cl . ~ F ~ ~ Rl benzeneJ ~ F b~
: (IV) (II) o CH-C-Cl (II) HO-CH ~ O ~ pyridine ~III) ~; X ~ CH-COO-CH ~ O

(I) wherein Rl is ethyl, _-propyl o~ l-propyl; R2 is hydrogen or cyano ' -' ''' ~ -- 111143~

. i With respect to the formation of the~-cyano-_-` phenoxybenzyl ester products by the procedures illustrated , , in Flow Diagram I, it is not necessary to prepare the~'-cyano-m-phenoxybenzyl alcohol precursor. It is equally or more satisfactory to allow a mixture of _-phenoxybenzaldehyde, an alkali cyanide such as sodium cyanide, and the appropriate ~-substituted 1,3-benzodioxole-5-acetyl halide to react together in one step to form the final ~-cyano ester.
The ester compounds of the invention are highly effective as contact and stomach poisons for ixodide ticks and for a wide variety of insects, particularly Dipterous, Lepidopterous, Coleopterous and Homopterous insects. The com-pounds are unusual among pyrethroids, in that they exhibit an extended residual insecticidal activity on plant tissue, they are effective in the soil, and are surprisingly effective for the control of ixodidae and the protection of animals against attack by insects and ixodidae when applied to the animals as a topical insecticidal or acaricidal formulation. They do not require admixture with a stabilizing agent to achieve insecticidal and acaricidal compositions having stabilized effects, however, they may be used in combination with other biological chemicals, for example pyrethroid synergists such as piperonyl butoxide, sesamex or n-octyl sulfoxide of iso-~: safrole. They may also be used in combination with conven-tional insecticides such as the phosphates, carbamates, formamidines, chlorinated hydrocarbons or halobenzoylureas.
- To achieve control of insects, including soil insects, which attack growing plants and/or harvested crops, including stored grain, the insecticidal compounds of this invention .

may be applied to the foliage of plants, the insect's habitat and/or the insect's food supply. Generally, the active com-pound is applied in the form of a dilute liquid spray; however, ;; it may also be applied as an aerosol, a dust, a granular, or a wettable powder formulation.
Liquid sprays which are particuarly useful are oil sprays and emulsifiable concentrates which can be further diluted for application. While they are, respectively, prepared as liquid concentrates; for convenience in handling and shipping, these formulations are usually dispersed in water at the site of their use and then applied as a dilute spray to the plant foliage, soil or surface of the area being treated.
A typical emulsifiable concentrate useful for pro-tecting a variety of crops such as cereals, cole crops, cucurbits, corn, eotton, tobacco, soybeans, ornamentals, shrubs, ;~ and the like, may comprise about 20% by weight of the active agent; 4% by weight of an emulsifying agent, conventionally employed in the preparation of pyrethroid formulations; 4% by weight of a surfactant; 25% by weight of an organic solvent such as cyelohexanone; and about 47% by weight of a petroleum solvent having a minimum aromatie eontent of about 83 volume %.

.
', 1~11434 Among the compounds of this invention which are useful : as insecticidal and acaricidal agents are:
m-Phenoxybenzyl ester of 2,2-difluoro-1,3-benzodioxole-5-.:
. (~ -ethyl)acetic acid;
~-Cyano-m-phenoxybenzyl ester of 2,2-difluoro-1,3-benzodi-oxole-5-(~-ethyl)acetic acid;
_-Phenoxybenzyl ester of 2,2-difluoro-1,3-benzodioxole-5-: (~-propyl)acetic acid;
~-Cyano-m-phenoxybenzyl ester of 2,2-difluoro-1,3-benzodi-oxole-5-(~-propyl)acetic acid;
m-Phenoxybenzyl ester of 2,2-difluoro-1,3-benzodioxole-5-(~-i-propyl)acetic acid;
~-Cyano-m-phenoxybenzyl ester of 2,2-difluoro-1,3-benzodioxole (~-l-propyl)acetic acid .:
'~' :
11~19L34 - 1 The invention is further described by the examples ` set forth below which are not to be construed as limiting the invention.
Example 1 Pre~aration of 2,2-Dichloro-5-methyl-1,3-benzodioxole A slurry of 5-methyl-1,3-benzodioxole ~52.6 g, 0.387 mole) and phosphorus pentachloride (102.4 g) in toluene is stirred and heated at 70C for 2 hours. The temperature is then raised to 90C over 30 minutes and held for 4 hours.
Phosphorus trichloride is distilled off at atmospheric pressure. Vacuum distillation yields 73.4 g of product 2,2-dichloro-5-methyl-1,3-benzodioxole (yield: 92%);
nD4 1.5325; b.p. 78-82C (at 0.4 mm); nmr (CDC13) ~ 2.28 (S 3H), 6.8 (m 3H).
Example 2 Preparation of 2,2-Difluoro-5-methyl-1,3-benzodioxole Dry dioxane (172 ml) and antimony (III) fluoride (56.2 g, 0.314 mole) are mixed and a part of the solvent (57 m) is distilled off. The mixture is cooled to room temperature and a solution of 2,2-dichloro-5-methyl-1,3-; benzodioxole (65.0 g, 0.317 mole) in dioxane (68 ml) is added dropwise over 30 minutes. During this time the temperature of the reaction mixture rises to 42C. The solution is refluxed for 7 hours, poured into a mixture of concentrated hydrochloric acid (100 ml) and water (100 ml), extracted with ether (3xlO0 ml). The ether extracts are combined, washed with water, dried over sodium sulfate . .
and evaporated. The residual oil is distilled under reduced - pressure (obtained by using a water-aspirator) to yield 29.3 g of product 2,2-difluoro-5-methyl-1,3-":
~ - 1 0 -:~.
. . .

11114~4 . .
1 (yield 53~); nmr (CDC13) ~ 2.28 (S, 3H), 6.8-6.8 (m, 3H).
Example 3 Preparation of 2,2-Difluoro-5-bromomethyl-1,3-benzodioxole A mixture of 2,2-difluoro-5-methyl-1,3-benzodioxole (29.0 g, 0.169 mole), N-bromosuccinimide (30.1 g, 0.169 mole), benzoyl peroxide (0.5 g) and carbon tetrachloride (50 ml) is refluxed for 2.5 hours. Carbon tetrachloride (50 ml) is then added to the hot reaction mixture and the solids are filtered off. The filtrate and washings are evaporated to 10 yield 41.0 g of product as a brown oil; nmr (CC14) ~ 4.38 (S, 2H), 6.8-7u4 (m, 3H). The product is used with-out purification in the next step.
Example 4 Preparation of 2,2-Difluoro-1,3-benzodioxole-5-acetonitrile To a solution of 2,2-difluoro-5-bromomethyl-1,3-~-` benzodioxole (41.0 g) in absolute alcohol (160 ml) at - 60-70C a hot solution of potassium cyanide (22.1 g, 0.34 mole) in water (30 ml) is added. There is a slight exotherm and within 5 minutes potassium bromide separates out of the reaction mixture. The reaction mixture is refluxed for ; 1.5 hours, cooled and added to ice-water. The mixture is . . .
; extracted with ether (3xlO0 ml), the combined extracts are - washed with water ~2x50 ml), dried over sodium sulfate and evaporated to afford a dark oil. Vacuum distillation yields 25 21.2 g of product (64% yield); b.p. 64-67C (at 0.03 mm);
- i.r. (neat) 2255 cm ; nmr (CC14) ~ 3.68 (S, 2H), 7.00 (S, 3H).
Example 5 Preparation of 2,2-Difluoro-1,3-benzodioxole-5-(~-isopropyl)-acetonitrile : `"

~' A solution of 50% sodium hydroxide (25 ml) is added to a solution of 2,2-difluoro-1,3-benzodioxole-5-acetonitrile (18.0 g, 0.0913 mole), 2-bromopropane (11.23 g, 0.0913 mole) and dicyclohexyl-18-crown-6* (1.7 g, 5 mole percent) in ;~ benzene (10 ml). The reaction temperature rises to 44-45C
over 15 minutes. The reaction mixture is then stirred at room temperature for 5 hours. More 2-bromopropane (2.8 g, ;~ 25 mole percent excess) is added and the reaction mixture stirred for 3 days. The organic layer is separated, the aqueous layer is extracted with ether (2x50 ml) and the extracts are combined with the organic layer. The combined organic solution is washed with water (2x50 ml), dilute ; hydrochloric acid (50 ml), water (2x50 ml), is dried over ~ .:
- sodium sulfate and evaporated to afford an oil. Vacuum distillation yields 16.35 g of product (75% yield);
b.p. 67-69C (at 0.03 mm); i.r. (neat) 2250 cm 1; nmr (CC14) ., .
8 1.05 and 1.08 (each d, J=7Hz, 611), 2.1 (m, lH), 3.68 (d, J=7Hz, lH), 7.05 (S, 3H).
By the above procedure, but substituting l-iodo-propane or iodoethane for 2-bromopropane, 2,2-difluoro-1,3-: benzodioxole-5-(~-propyl)acetonitrile and 2,2-difluoro-1,3- benzodioxole-5-(-ethyl)acetonitrile are prepared, respectively.
;. * The structure of dicyclohexyl-18-crown-6 is:

.. ~

G~ o~

' ~

. :

1 Example 6 Preparation of 2~2-Difluoro-1~3-benzodioxole-5-(~-isoprOpyl)-acetic acid A mixture of 2,2-difluoro-1,3-benzodioxole-5-(~-isopropyl)acetonitrile (13.5 g), potassium hydroxide pellets (20.0 g) in ethylene glycol (100 ml) and water (20 ml) is heated at 140C with stirring for 14 hours. After cooling, the reaction mixture is poured into water and extracted with ether (2x50 ml). The aqueous portion is cautiously acidified with hydrochloric acid and extracted with ether (3x50 ml).
` The combined extracts are washed with water (2x50 ml), dried over sodium sulfate and evaporated to dryness. Recrystalliza-~', r , tion of the solid residue from heptane affords 9.4 g of product (64% yield); m.p. 98-101C, i.r. (Nujol mull) 1700 cm ; nmr (CDC13) ~ 0.75 (d, J=8Hz, 3H), 1.10 (d, J=8Hz, 3H), 2.3 (m, lH), 3.16 (d, J=lOHz, lH), 7.0-7.2 (m, 3H).
; By the above procedure, but substituting 2,2-di-fluoro-1,3-benzodioxole-5-(~-propyl)acetonitrile and 2,2-di-fluoro-1,3-benzodioxole-5-(~-ethyl)acetonitrile for 2,2-di-fluoro-1,3-benzodioxole-5-(~-isopropyl)acetonitrile, 2,2-di-fluoro-1,3-benzodioxole-5-(propyl)acetic acid and 2,2-di-fluoro-1,3-benzodioxole-5-(ethyl)acetic acid are prepared, respectively.
Example 7 Preparation of 2,2-Difluoro-1,3-benzodioxole-5-(~-isopropyl)-acetyl chloride A solution of 2,2-difluoro-1,3-benzodioxole-5-(~-isopropyl)acetic acid (5.16 g, 0.02 mole) and thionyl chlo-ride (2 ml) in benzene (10 ml) is refluxed for 4 hours.
Evaporation of the solvent and excess thionyl chloride ~ /rc~ rk 1~1143'~
:
1 affords the title product which is used without further purification in the subsequent step.
By the above procedure, but substituting 2,2-difluoro-1,3-benzodioxole-5-(~-propyl)acetic acid and 2,2-difluoro-1,3-benzodioxole-5-(~-propyl)acetic acid or 2,2-difluoro-1,3-benzodioxole-5-(~-ethyl)acetic acid for 2,2-difluoro-1,3-dioxole-5-(~-isopropyl)acetic acid, 2,2-di-fluoro-1,3-dioxole-5-~-propyl)acetyl chloride and 2,2-di-fluoro-1,3-benzodioxole-5-(~-ethyl)acetyl chloride are prepared, respectively.

Example 8 :
Preparation of ~-Cyano-m-phenoxybenzyl ester of 2,2-difluoro-1,3-benzodioxole-5-(~-isopropyl)acetic acid A solution of 2,2-difluoro-1,3-benzodioxole-5-(~-isopropyl)acetyl chloride (0.01 mole) in ether (10 ml) is added to a solution of a-cyano-m-phenoxybenzyl alcohol 2.03 g, 90 mole percent) and pyridine (0.8 g) in ether (25 ml) at room temperature. The reaction mixture is stirred overnight at room temperature. The solids are filtered off, ;~
; 20 and the filtrate and washings are evaporated to yield an oil.

The oil is purified by dry column chromatography on silica gel using 1:1 methylene chloride-hexane as eluent to afford

3.40 g of title product (73% yield; nmr (CDC13) 0.6-1.1 (set of d, 6H), 2.3 (m, lH), 3.2 (d, J=lOHz, lH), 6.30 and . .
6.35 (S, lH), 6.8-7.5 (m, 12H).
By the above procedure, but substituting 2,2-di-fluoro-1,3-benzodioxole-5-(~-propyl)acetyl chloride and 2,2-difluoro-1,3-benzodioxole-5-(~-ethyl)acetyl chloride the ~-cyano-m-phenoxybenzyl esters of 2,2-difluoro-1,3-benzod-oxole-5-(~-propyl)acetic acid and 2,2-difluoro-1,3-benzo-'.~

' ``` 111~434 1 dioxole are prepared, respectively.
Example 9 Preparation of m-Phenoxybenzyl ester of 2,2-difluoro-1,3-benzodioxole-5-(~-isopropyl)acetic acid The title compound is prepared by the procedure of Example 8 by substituting m-phenoxybenzyl alcohol for ~-cyano-m-phenoxybenzyl alcohol; nmr (CDC13) ~ 0.65 and 0.95 (each d, J=8H2, 6H), 2.3 (m, lH), 3.15 (d, J=lOHz, lH), 5.02 (Collapsed AB pattern, 2H) 6.7-7.4 (m, 12H).
By the above procedure, but substituting 2,2-di-fluoro-1,3-benzodioxole-5-(~-propyl)acetyl chloride and 2,2-difluoro-1,3-benzodioxole-5-(~-ethyl)acetyl chloride, the m-phenoxybenzyl esters of 2,2-difluoro-1,3-benzodioxole-~ 5-(a-propyl)acetic acid and 2,2-difluoro-1,3-benzodioxole-5-- 15 (~-ethyl)acetic acid are prepared, respectively.
Example 10 Residual insecticidal activity obtained with foliar treatment of cotton ~lants Young cotton plants with at least two expanded ~; 20 true leaves growing in 10 cm plastic pots were dipped, usually one leaf at a time, in a 65~ acetone--35~ water solu-tion of test compound with agitation for three seconds. The concentration of each compound in the solutions was 30 ppm, . .
100 ppm, 300 ppm or 900 ppm of active ingredient.
After the leaves had dried, two leaves from each of two plants were excised and placed in petri dishes (90 mm x 10 mm) on moist filter paper (9 cm Whatman No. 1). Five third instar tobacco budworm larvae were placed on each leaf and the petri dish capped. The infested dishes were then placed in the holding room with continuous light, 1~11434 1 ambient temperature of 80F and 50~ r.h. Larval counts were made after 72 hours~
The remaining plants were placed under high inten-sity lights in the greenhouse adjusted to provide 14 hours of light per day. Leaf samples were assayed with third instar tobacco budworm larvae after 3, 7, 10 and 14 days exposure in the greenhouse.
The data obtained are summarized in Table I. The well-known pyrethroid permethrin is included as a reference standard.

, :., ,"' . .
~ 15 , .

, ~ "
, .
~ 20 ;"

'' ~..

,.- _ _ ~o~oo ~oo o _ N~ 00 O ~ r~ ~o O
_ _ , . O O ~ O O O OU~ Ln O O ~
~1 ~ O 1:~ 0 0 (`I 00 0 _ _ _~ ~ O O O O O ~ ~ O O CO
. ~1 ~I 00 ~) :, H ~ O O IJ ) O O Ir~ O L~l O 111 1/~ O O
:` ~ ~ _I ~ ~Cl ~ O ~ O~ t~'l 3 ~ ~ _ E-~ ¢ ~ ~ o o o Cl ou~ ~ o d ., ~ N1~ _1 ~ O
,: ~4 ~ ~ ~ ~
,~ ~ I~ _ ._ .. _ _ :: ~ U~ O 11~ 0 0 O O O IJ7 0 0 ~ 11~
c~ ~ ~ ~ o o o ~ o ~ r~ o o _ :. ~ ~ ~00 000 ~000 :, , O V~ _,,, .. _ a~
~ o t~ . E3 ' ' O ~r~ ~O L~ O O Lr) O O O Ln O O O ~d ~ ~ I~ O ~) O O Iff 00 0 0 C:~ .
g ~0 _ _ ,~
~ ~n *`D O O O O O O ~ O O ~ O ~
''.. '. ~ ~ * _1 O ~0 ~ ' ~' ~ ~ ~ _ _ 'o\
" ~~ E o ~co o u~ ou~ o o m Lr) o Ob4 _I ~ a~ o oo O O ~ 0 0 O ~d . .
3 ~ _~ ~ ~ a) ,'. E~ ~ ----- ----~-- __ ¢
o o ~ Ei o o o a o o o o o o o *
~d ~~ O 00O O O ~0~ 0 l *
:, ~ Cd C~ ~~ ~ cn~ ~ a- ~ ~ a~
--~ ~ ~ 1 ~

_~ ~ ~ ¦ ~ A ~ O ¦ V

~ ~ 1 ~ h ~o 0/--\o 3~( to ¢
,~ a ll ~ ~ / .~.... ~ _ . , ':
Example 11 - The effectiveness of the compounds of the invention for controlling adult ~oophilus microplus ticks is determined in the following tests wherein test compound is dissolved in 10% acetone-90% water mixture in sufficient amounts to give solutions containing 125, 62.5, 31.2, 15.6 or 7.3 ppm of test compound.
Adult engorged female ticks are then dipped in the . , : test solutions for 3 seconds and placed in individual con-- 10 taincrs and held for 48 hours in a room maintained at 80F
, and 50% r.h. At the end of the holding period the ticks are examined and egg deposits counted. Engorged females that do not deposit eggs are considered dead. Data obtained are ; reported below in Table II.

; . .
~,,.~ .
, .

, ' ' .

.

.~.

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

.434 ., ~ ~ N O ~:t ~ 1 t') ~ 00 '~., '~ a~ O N O t'~
I ~ 1 ~S ~ ~

' , .

~ . ~
- ` 1111434 :

1 Example 12 Insecticidal Activity The insecticidal activity of the compounds of this invention is demonstrated in the following tests, wherein Tobacco budworm, Heliothis virescens (Fabricius); Western Potato Leafhopper, Empoasca abrupta DeLong and Bean Aphid, ;~ Aphis fabae (Scopoli), are employed as test insect species.
; Procedures employed are as follows:
Tobacco Budworm Heliothis virescens (Fabricius).
; 10 First Instar ` A cotton plant with two true leaves expanded is dipped for 3 seconds with agitation in a test solution (35%
water/65% acetone) containing 300, 100 or 10 ppm of test compound. Each leaf is placed in a cup with a wick and a piece of cheesecloth infested with 50-100 newly hatched larvae is added before covering the cup with a lid. After ; 3 days at 80F, 50~ r.h., the cups are examined and the kill of newly hatched larvae noted. Data obtained are reported as percent kill in Table III.
Bean Aphid, Aphis fabae (Scopoli).
Five cm fiber pots, each containing a nasturtium plant 2 inches high and infested with 100 to 150 aphids 2 days earlier are placed on a 4 rpm turntable and sprayed with a 35% water/65% acetone solution containing 100, 10, 1.0 and 0.1 ppm of test compound for 2 revolutions using a DeVilbiss Atomizer and 20 psi air pressure. The spray tip is held about 15 cm from the plant and the spray directed so as to give complete coverage of the aphids and the plants.
The sprayed plants are lai~ on their sides on white enamel ` 30 trays. Mortality estimates are made after 1 day at 70F, l 50~ r.h.
Data are reported as percent mortality determined at the rate indicated (Table III).
Western Potato Leafhopper, Empoasca abrupta DeLong A Sieve lima bean plant with the primary leaf - expanded to 3 to 4 inches is dipped into 35% water/65% ace-tone solution containing lO0, lO or l ppm of test compound.
The dipped plant is placed in the hood to dry and then a 2.5 cm plece of the tip of one leaf is cut off and placed in a 4-inch petri dish with a moist filter paper in the bottom. From 3 to lO second-instar nymphs are placed in the dish and the dish is then covered. Mortality counts are made after holding the thus-prepared dish for 2 days at 80F
and 50 r.h. Data obtained are reported in Table III. In these tests permethrin is used as a standard or check.

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: - -`` 111~34 1 Example 13 Insecticidal Activity The insecticidal activity of the compounds of the present invention, is further demonstrated by the following tests.
The procedures employed for evaluation against mosquito larvae, Mexican sean seetles and Southern Armyworms are as follows.
Malaria Mosquito - Anapheles quadrimaculatus Say 1 Milliliter of a 35% water/65% acetone solution containing 300 ppm of test compound is pipetted in a 400 ml beaker containing 250 ml of deionized water and stirred with the pipette, giving a concentration of 1.2 ppm. Aliquots of this solution are taken and further diluted to .4, .04, and .004 ppmO A wax paper ring 0.6 cm wide to fit inside the beaker is floated on the surface of the test solution to keep the eggs from floating up the meniscus curve and drying out on the side of the glass. A spoon made of screen is used to scoop up and transfer about 100 eggs ~0-24 hours old) into the test beaker. After 2 days at 80F, 50% r.h., observations of hatching are made. Percent mortality records are pre-sented in Table IV.
Mexican Bean Beetle Epilachna varivestis Mulsant .
Sieva lima bean plants (2 per pot) with primary leaves 7.5 to 10 cm long, are dipped in the 300, 100, 10 or 1 ppm test solution and set in the hood to dry. One leaf is removed from a plant and placed in a 10 cm petri dish con-taining a moist filter paper on the bottom and 10 last-instar larvae (13 days from hatching). The day after treatment, another leaf is removed from the plant and fed to the larvae ``':' .
1 after removing the remains of the original leaf. Two days ;~^ after treatment, the third leaf is fed to the larvae, this ` usually being the last needed. The fourth leaf is used on - the third day after treatment if the larvae have not finished - 5 feeding. The test is now set aside and held until adults have emerged, usually in about 9 days after treatment began.
After emergence is complete, each dish is examined for dead larvae, pupae or adults; deformed pupae or adults; larval-pupal intermediates or pupal-adult intermediates; or any other interference with normal molting, transformation and emergence of pupae or adults.
Data obtained are reported in Table IV.
; Southern Armyworm - Spodoptera eridania ~Cramer) ;
Methods:
Sieva lima bean plants, with two expanded 7.5 to 10 cm primary leaves, are dipped three seconds with agitation in the treatment solutions and then set in a hood to dry.
After the leaves are dry they are excised and each excised leaf is placed in a 10 cm petri dish containing a piece of moist filter paper and 10 third-instar southern armyworm ~- larvae approximately 1 cm long. The petri dishes are cover-- ed and placed in a holding room for 2 days at a temperature - of 80F and 50% relative humidity.
` Mortality counts are made after 2 days. Results ` 25 obtained are presented in Table IV.

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.: ~, .434 1 Example 14 Insecticidal Activity Two-Spotted Spider Mite - Tetranychus urticae (Koch) Sieve lima bean plants, with primary leaves three 7.5 to 10 cm long, are infested with about 100 adult phos-phate resistant mites per leaf four hours before use in this test, in order to allow egg-laying before treatment. The infested plants are dipped for three seconds with agitation into the 300, 100 or 10 ppm solution, and the plants set in ; the hood to dry. After 2 days at 80F, the adult mite mortality is estimated on one leaf under a lOX stereoscopic microscope. The other leaf is left on the plant an addi-tional five days and then examined at lOX power to estimate the kill of eggs and of newly-hatched nymphs, giving a measure of ovicidal and residual action, respectively. Test results are provided in Table V.
; Tobacco Budworm - Heliothis virescens (Fabricus) Third Instar Three cotton plants with just expanded cotyledons are dipped in 1000 or 100 ppm solution and placed in the hood to dry. When dry, each cotyledon is cut in half, and lO~leaf sections are each placed in a 28 g plastic medicine cup containing a 1.25 cm dental wick saturated with water and one third-instar budworm larva is added. The cup is capped and held for 3 days at 80F 50~ r.h., after which mortality counts are made. Test results provided in Table V.
Cabbage Looper - Trichoplusia n1 (Hubner) - Third Instar A true leaf on a cotton plant is dipped into the test solution containing 1000 or 100 of test compound, agitated for 3 seconds, and removed to dry in an exhaust ~111434 1 hood. When dry, the leaf is placed in a 9.0 cm petri dish with moist filter paper on the bottom. Ten third-instar larvae are added and the lid placed on the dish. Mortality counts are made after 3 days at 80F and 50 + 10~ r.h.
Data obtained are reported in Table V below.
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Data obtained are reported in Table VI below where it can be seen that the compounds of the invention are more effective than the art compound for controlling adult Anopheles quadrimaculatus.

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Claims

We Claim:

1. A compound having the formula:

wherein R1 is ethyl, n-propyl or i-propyl and R2 is hydrogen or cyano.

2. A compound according to Claim 1, wherein R1 is ethyl, n-propyl or i-propyl and R2 is hydrogen.

3. A compound according to Claim 1, wherein R1 is ethyl, n-propyl or i-propyl and R2 is cyano.

4. A compound according to Claim 2, the m-phenoxy-benzyl ester of 2,2-difluoro-1,3-benzodioxole-5-(a-ethyl)-acetic acid.

5. A compound according to Claim 2, the m-phenoxy-benzyl ester of 2,2-difluoro-1,3-benzodioxole-5-(a-propyl)-acetic acid.

6. A compound according to Claim 2, the m-phenoxy-benzyl ester of 2,2-difluoro-1,3-benzodioxole-5-(a-i-propyl)-acetic acid.

7. A compound according to Claim 3, the a-cyano-m-phenoxybenzyl ester of 2,2-difluoro-1,3-benzodioxole-5-(a-ethyl)acetic acid.

8. A compound according to Claim 3, the a-cyano-m-phenoxybenzyl ester of 2,2-difluoro-1,3-benzodixole-5-(a-i-propyl)acetic acid.

9. A method for controlling insects and acarina, comprising contacting the insects and acarina, their habitat, breeding grounds or feed, with an insecticidally or acarici-dally effective amount of a m-phenoxybenzyl ester of a 2,2-difluoro-1,3-benzodioxole-5-(.alpha.-alkyl)acetic acid having the structure:

wherein R1 is ethyl, n-propyl or i-propyl and R2 is hydrogen or cyano.

10. A method according to Claim 9, wherein the compound is the m-phenoxybenzyl ester of 2,2-difluoro-1,3-benzodioxole-5-(.alpha.-isopropyl)acetic acid.

11. A method according to Claim 9, wherein the compound is the .alpha.-cyano-m-phenoxybenzyl ester of 2,2-difluoro-1,3-benzodioxole-5-(.alpha.-isopropyl)acetic acid.

12. A method for the preparation of a compound having the formula:

wherein R1 is ethyl, n-propyl or i-propyl and R2 is hydrogen or cyano comprising reacting a compound having the structure:

wherein X is halogen and R1 is as described above with a m-phenoxybenzyl alcohol having the formula:

wherein R2 is as described above, in the presence of a tertiary organic amine acid acceptor and an inert organic solvent at a temperature of from 10°C to 30°C.