US3711495A - Isoxazalin-3-yl-substituted-5-nitroimidazoles - Google Patents

Abstract

Substituted nitroimidazoles having a 1-alkyl or hydroxyalkyl substituent; a 5-nitro substituent; and a 2-substituent, the latter being a Delta 2-4,5-disubstituted-isoxazoline. The 4,5substitution on the isoxazolinemoiety is a saturated alkyl ring structure. These compounds have anti-bacterial and anti-protozoal activity against human and animal trypanosomiasis and trichomoniasis.

Description

United States Patent 1 1 Kulsa et al.

1541 ISOXAZALIN-ZLYL-SUBSTITUTED-S;

NITROIMIDAZOLES [75] Inventors: Peter Kulsa, Scotch Plains, N.J.;

Clarence S. Rooney, Beacons'field, Quebec, Canada [52] Cl. ..260/307. D, 260/239.3 B, 260/247, 260/296 B, 260/307 F, 260/307 H, 260/309,

424/263,424/272 51 Int. Cl. ..C07d 85/16 58 Field ofSearch ..260/307D [151 Jan. 16, 1973 56] References Cited UNITED STATES PATENTS I 3,472,857 10/1969 Arya .260/268 Primary Examiner- Alex M azel Assistant ExaminerR. V. Rush Attorney-J. Jerome Behan, I. Louis Wolk and Hesna J. Pfeiffer [5 7] ABSTRACT Substituted nitroimidazoles having a l-alkyl or hydroxyalkyl substituent; a S-nitro substituent; and a .2-substituent, the latter being a A -4,5-disubstitutedisoxazoline. I The 4,5-substitution on the isoxazolinemoiety is a saturated alkyl ring structure. These compounds have anti-bacterial and anti-protozoa] activity against human and animal trypanosomiasis and trichomoniasis.

' 4 Claims, No Drawings This invention relates to isoxazol-3-yl-, A isoxazolin-3 -yl-, or

hydrogen, the substituent other than hydrogen is on the 5-position of the ring. Whenever the term alkyl' is used throughout the specification, a

lower alkyl group having l-6 carbon atoms is intended.

isoxazolidin-3-yl-substituted-5- nitroimidazoles.

These compounds have the followin respective structures:

N I l H OzN N ..'R: I II R o B:

| H H OzN R2 N l h/ ko R3 Y 1b ozNl I R4 N I R wherein R is hydrogen, loweralkyl having l-6 carbon atoms, or -CH CH OH, Y is loweralkyl having l-6 carbon atoms, benzyl, or hydrogen, R, and R are the same or different and are each hydrogen, loweralkyl having 'l-6 carbon atoms, carboxyalkyl, carboxamido, carboxamidoalkyl, carboxamidodialkyl, amino, phenyl, aminoalkyl, aminodialkyl, or R and R are a ring structure having the following structure:

7.- n equals an integer 3-10;

C (CHz);C 2)m m equals an integer from 1-3; 1?. equals an integer from 1-2;

I {e112s 02-011.}- em)m0- m equals an integer from 2-3;

z Z equals hydrogen or benz'oyl;

CNH(CHi),.

n, equals an integer from 1-4;

tiltand R and R are the same or different and are each hydrogen, loweralkyl havingl-6 carbon atoms, carboxylalkyl, carboxamido, carboxamidoalkyl, carboxamidodialkyl, amino, phenyl, aminoalkyl, or aminodialkyl; or R and R are a ring structure of -C H,+,,, n equals an integer from 3'l0; except that when only one of R, and R or R and R are derivative The novel compounds disclosed in this invention are prepared following three different processes. The isoxazolyl derivatives are prepared by reacting an acetylene with I a hydroxamoyl chloride.

The A -isoxazolinyl derivatives are prepared by reacting an olefin with a l-loweralkyl-5-nitroimidazol-2 '-hydroxamoyl chloride.

The isoxazolidinyl derivatives are prepared by reacting an olefin with an a-( l-methyl-5-nitroimidazol-'2- yl)-N-alkylnitrone. These processes are separately discussed in greater detail hereinafter.

The reactive olefin used to prepare both the A -isox- ,azolinyl and the isoxazolidinyl derivatives can be amidodialkyl, phenyl, or R and R are a ring structure having the following structure:

11 equals an integer from 31();

H H ocH2)uo 2)m m equals an integer from 1-3; n equals an integer from- 1-2;

v 1 m equals an integer from 1-3;

Z equals hydrogen or benzoyl;

|CNH-(CHz)n n equals an integer from 1-4;

The acetylene compound used to prepare the isoxazolyl derivative can be defined as R -C C---R wherein R and R are the same or different and are each hydrogen, loweralkyl having l-6 carbon atoms, carboxyalkyl, carboxamido, carboxamidoalkyl, carboxamidodialkyl, or phenyl.

The above acetylene compound is reacted with the chosen l-loweralkyl-5-nitroimidazol-2-hydroxamoyl chloride of the following structure:

wherein R is hydrogen, loweralkyl having l-6 carbon atoms, or CH CH OH, to prepare the isoxazolyl derivative. The hydroxamoyl chloride is prepared from the 2- formyll -'substituted-5 -nitroimidazole following 1-loweralkyl-S-nitroimidazol-Z- procedures known in the art. For example, reaction with hydroxylamine is followed by chlorination with nitrosyl chloride. Preparation of the 2-formyl starting material is described in Belgium Pat. No. 661,162 issued Sept. 17, 1965.

The acetylene and the hydroxamoyl chloride are reacted in an inert solvent such as tetrahydrofuran, benzene, or chloroform. The molar ratio of the hydroxamoyl chloride to the acetylene is approximately 1:1,

although 1:l-15 can be used. The reaction takes place in the presence of an organic base, such as an alk'ylamin'e, for example, triethylamine, N-methyl piperidine, or any suitable tertiary amine. The temperature of the reaction is preferably -25C. Lower temperatures, may be used, to 20C., and the operable upper temperature limit is such that substantially no acetylene polymerization occurs. The reaction takes place in from onehalf to' hours.

it is noted that neither the reactive olefin nor the reactive acetylene contain the substituents amino, aminoalkyl, or amiriodialkyl, although this moiety can be present on the final nitroimidazole. The process of preparing these functionsutilizes firstan olefin or an acetylene containing either a carboxyalkyl or a carboxamido group at any one of positions R R R or R The reaction with the desired nitroimidazole is completed as described above; the final isoxazolyl-, A isoxazolinyl-, or isoxazolidinyl-nitroimidazole is prepared. This nitroimidazole is then hydrolyzed in acidic or basic aqueous solution to remove either the carboxyalkyl group or the carboxamido group, thereby producing the free carboxylic acid functionality at positions R R R or R of the corresponding ring. Following hydrolysis, the acid chloride is, prepared by reacting withthionyl chloride or oxalyl chloride. The acid chloride is then reacted with an alkali metal azide, such as sodium, potassium, or lithium azide to prepare the acid azide of the nitroimidazole. This latter acid azide can be rearranged to the corresponding isocyanate by heating to reflux in an inert organic solvent such as benzene, xylene, or the like. The isocyanate can be treated with mineral acid such as HCl, H 80 or the like to'prepare the free amino substituent. Alternately, the isocyanate can be reacted at elevated temperatures with methanol in an inert organic solvent as above to prepare the carbamate, and the latter removed by acid or base hydrolysis to yield the final amine.

After the amine is obtained on the ring, the nitroimidazole can be treatedwith a loweralkyl halide, loweralkyl having 1-6 carbon atoms, for instance, methyl iodide, ethyl chloride, n-butyl iodide, hexyl bromide, or the like. An inert organic solvent such as ethanol, methanol, dimetl'iyl formamide, and an elevated temperature between 60l C. can be used.

' The amino group at R, R, R, or'R is then alkylated within 1 3 hours. If a luoioeulur equivalent! is used. the secondary amine is produced, or an uminoalkyl group at R R R or'R If an excess of reagent is used, the tertiary amine, the aminodialkyl group,;is produced at R R R or R, if an unsymmetrical tertiary amine is desired, the reaction can be conducted in two stages, with a molecular equivalent of each desired alkyl halide being used in each step.

.The above described acetylene can only be used to prepare an isoxazolyl derivative in which R and R are not joined in a ring structure. When an isoxazolyl derivative is desired which has a cyclic substituent on positions 4 and 5 of the isoxazole ring, a morpholinosubstituted olefin having the following formula;

OzN

This latter compound can be isolated, and treated with a strong mineral acid to remove the element of morpholine thereby preparing the desired compound:

The A -isoxazolinyl derivatives are also prepared from the l-loweralkyl-S-nitroimidazol-2-hydroxamoyl chloride by reaction of the latter with the olefin defined above. There are two different sets of process conditions. In one route, the olefin and the ,hydroxamoyl chloride are reacted in an inert solvent at reflux. The solvent is chosen so that the reflux temperature is preferably l00-l50C., and can be- -200C. The ratio of hydroxamoyl chloride to olefin is approximately lzl. although l:l-l 5 can be used. The reaction takes place inabout 18 to 24 hours.

The other route used to prepare the A -isoxazolinyl derivative utilizes the presence of an organic base, such as alkylamine, for example, triethylamine, N-methyl piperidine or any other suitable tertiary amine. The reaction takes place in a solvent such as tetrahydrofuran atlow temperatures, preferably from O-25C. The reaction takes place in from one-half to 10 hours.

mula:

H OzN Nic I l I E O Y III wherein R is hydrogen, loweralkyl having 1-6 carbon atoms, or Cfl Cl-l Ol-l, and Y is H, loweralkyl or benzyl. This nitrone can be prepared from a 2-formyll-substituted-5-nitroimidazole by reaction with a benzylor alkyl-substituted-hydroxylamine, such as c a n. U--. a

wherein Y is hydrogen, a benzyl radical or an alkyl radical having 1-6 carbon atoms. The hydroxylamine can preferably be employed in the salt form, such as the hydrochloride, acetate, carbonate and others, or in the free base form. The two reactants are mixed together and allowed to react at room temperature to 60C. for 2-12 hours in a solvent such as methanol, ethanol, or water. The desired product can be isolated after the solution is made alkaline with an inorganic base.

The chosen nitrone is then reacted with an olefin chosen from the group described above. The reactants are reacted in an inert solvent at reflux, and operably at a temperature of about 80-200C., and preferably ll50C. The ratio of nitrone to olefin is approximately lzl, although l:l-l can be used. The reaction takes place in about 1-1 2 hours.

The novel compounds of this invention have antibacterial and antiprotozoal activity especially against human and animal trypanosomiasis, including Chagas disease, and trichomoniasis.

Trypanosomiasis is a term used to describe a group of allied protozoal diseases,each of which is due to infection with a species of the genus Trypanosoma. They reach their greatest importance in Africa where their presence in enz ootic form precludes the keeping of domestic animals throughout the largest part of the continent between l5N and S latitude. The pathogenic trypanosomes of Africa are considered to be primarily associated with the tsetse flies (glossina) which feed on vertebrate blood. Wherever tsetse are present, trypanosomiasis will also be found in some part of the mammalian population. The clinical findings are typically those of a wasting disease with intermittent fever. Anemia, edema, and cachexia are parts of the syndrome. r The important trypanosomes pathogenic to domestic animals are T. congolense, T. simiae, T. vivax, and T. brucei. The latter trypanosome is morphologically identical to T. gambiense, responsible for human sleeping sickness of Africa. A trypanosome found in the Western Hemisphere is T. cruzi, which affects both domestic animals and man.

Acute Chagas" disease (T. cruzi) occurs predominantly in young children. The chronic form may be mild and asymptomatic, but complications from myocarditis and C.N.S. involvement may result with fatal outcome.

Trichomoniasis is a protozoan disease affecting cattle, poultry, and humans, In cattle the causative protozoan is Trichohiona s fetus which produces a contagious venereal disease characterized by sterility, pyometra and abortion. Trichomonas gallinarum invades the lower intestine of domestic birds and causes diarrhea'an'd lesions in the intestinal wall. In humans the infective protozoa are Trichomonas vaginalis, infecting the vagina and prostrate, and Trichomonas hominis, found in the intestine.

The compounds of this invention have particular value in the control of trypanosomiasis and trichomoniasis in domesticated animals, particularly cattle. For this purpose, they may be administered orally with an ingest'ible carrier as a component of the animal feedstuff, in the drinking water, in salt blocks and in unit dosage forms such as boluses and drenches. The amount of active ingredient required for optimum control of trypanosomiasis varies in accordance with such factors as the particular compound employed, the species of animal to be treated, the species of infecting parasite, the severity of infection, and whether the compound is employed therapeutically or prophylactically. In general, the compounds defined by Formula I, when administered orally to domestic animals in daily doses of from about 0.1 mg. to about 500 mg. per kilogram of animal body weight are highly effective in controlling trypanosomiasis and trichomoniasis without intolerable toxic effect. When these compounds are to be employed as therapeutic agents, good results are obtained when the animals are fed a daily dose of from about 5 mg. to about 500 mg. and preferably 15 mg. to 250 mg. per kilogram of body weight.

Administration may be in a single dose or divided into a plurality of smaller doses over a period of 24 hours. Where prophylactic treatment is desired and the compounds are fed continuously, satisfactory results are obtained when the animals ingest daily dosages of about 0.1 mg. to lOO mg. per kilogram of body weight. The unit dosage'forms may be'readily prepared by conventional formulating techniques and are particularly useful when administration is to be made in a single dose. or divided doses over a period of 24 hours.

The exact amount of active ingredient to be employed in'the above compositions may vary provided that a sufficient amount is ingested to give the required dosage. In general, tablets, boluses and drenches containing from about 5 to percent weight of active ingredient may be satisfactorily employed to supply the desired dosage. v

The substituted imidazoles defined by Formula 1 above may be administered, dispersed in or admixed with the normal elements of animal sustenance, i. e., the feed, drinking water or other liquids normally partaken by the animals. This method is preferred when it is desired to administer the active compounds continuously, either as a therapeutic or prophylactic agent, for a period of several days or more. However, in such usage, it is to be understood that the present invention also contemplates the employment of compositions containing the active compounds intimately dispersed in or admixed with any other carrier or diluent which is inert with respect to the active ingredient, orally administrable and is tolerated by the animals.

When the compounds described according to Formula l above are provided as a constituent of the feed,

.solid edible carrier such as corn meal, wheat shorts, a1-

falfa, etc. In general, feed supplements containing from about percent to about 50 percent by weight of active ingredient may be satisfactorily employed to supply the desired .dosage in the finished feed.

In the preparation of feed supplements, the active ingredient is added to the carrier and the whole mixed to give substantially uniform dispersion of the antitrypanosomiasis agent in the carrier.

When the substituted nitroimidazoles of this invention' are used in the prevention and treatment of Chagas disease and human sleeping sickness, the compounds can be administered .as intravenous, intramuscular, or interperitoneal injections. The compounds are suspended or dissolved in an inert non-toxic pharmaceutically acceptable carrier and administered. When used as a prophylactic, 2-12 mg./l g. of body weight are injected every 1-8 months. The compounds can also be used orally against Chagas disease or human sleeping sickness. The oral dosage is 3 -20 mg. per kg. twice a day for 5-10 days. This therapy can be given alone or in addition to other drugs useful against trypanosomiasis, such as sodium s'uramin, melarsoprol, tryparsamide, or pentamidine.

The compounds of the present invention are also useful as topical trichomonacides. When employing the compounds in this manner, one or more of the active agents are uniformly distributed in a suitable chemotherapeutic vehicle that is chemically compatible with the particular compound selected, non-inhibiting with respect to the action of the effective agent upon the parasite and essentially non-injurious to body tissue under the conditions of use. The vehicle is preferably a semi 1iquid or semi-solid type and the final preparation may be in the form of a suppository if desired.

Oil and water types of emulsions or creams as well as aqueous jellies such as those prepared with the aid of EXAMPLE 1 1-Methyl-5-nitroimidazole 24.2 0., (0.214 moles) of 4(5)-nitroimidazole is heated with 24.0 g. (0.1 1 mole) of methyl tosylate for 1 hour at l80190C. and cooled to give a hard solid. The mixture is shaken with 175 ml. of 2.5 N aqueous sodium hydroxide until it is dissolved and diluted with 175 ml. of water to give an oily precipitate. The mixture is extracted with ether; the ether extract washed with 2.5 N aqueous hydrochloric acid and water. The aqueous acid wash is treated with excess aqueous sodium hydroxide and extracted with ether. This latter ether extract is evaporated to dryness and recrystallized from petroleum ether to yield l-methyl-S- nitroimidazole, m.p. 154155C.

In accordance with the above procedure but starting with ethyl tosylate, propyl tosylate, or n-butyl tosylate in place of methyl tosylate, there is obtained l-ethyl-5- nitroimidazole; l-propyl-5-nitroimidazole and Imbutyl-S-nitroimidazole.

EXAMPLE 2 v 0 l-Methyl-2-hydroxymethyl-5-nitroimidazole 27.9 g.'of l-methyl-5-nitroimidazole prepared as in Example l and 30.1 g. of paraformaldehyde are added to 154 ml. of dimethylsulfoxide and the resulting solution is sealed'into a glass-lined tube. The solution is heated at 110C. for 24 hours, with shaking. The

' tively, the following compounds are prepared: l-ethyl- 2-hydroxymethyl-5-nitroimidazole; 1-propyl-2-hydroxany of a number of commercially used j'elling agents including acacia, tragacanth, bentonite, alginic acid and the like are suitable vehicles. The vehicle may also be a viscous aqueous gel containing one or more cellulose derivatives such as methyl cellulose, hydroxyethyl cel-' lulose, and sodium carboxym'ethyl cellulose. Gelling agents such as pectin, gum tragacanth, sodium alginate and other vegetable gelling agents are also useful vehicles in this regard.

This invention is more fully described in a reading of 'ymethyl-5-nitroimidazole; 1-n-butyl-2-hydroxymethyl- 5-nitroimidazole; and 2-hydroxymethyl-5- nitroimidazole.

EXAMPLE 3 1-Methyl-2-formyl-5-nitroimidazole 100 g. (0.64 mole) of l-methyl-2-hydroxymethyl-5- nitroimidazole prepared as in Example 2 is dissolved in 3,500 ml. of benzene at C. There is added over a 20 minute period 460g. of lead tetraacetate (previously' diacetate precipitates from the solution. The mixture is allowed to stand overnight at room temperature, and

' the lead diacetate then removed by filtration and washed ,with 2 X mlof benzene. The combined benzene filtrate and washes are extracted with 1 ,500 m1. of water and then with two 1 liter portions of saturated aqueous potassium bicarbonate.

The dried extracts are evaporated in vacuo to give a residue of substantially pure l-methyl-Z-formyl-S- nitroimidazole. Recrystallization of the product from 500 ml. of boiling hexane affords 79 g. of l-methyl-2- formyl-S-nitroimidazole, m.p. 9094C.

When this general procedure is followed using 1- ethyl-2-hydroxymethyl-5-nitroimidazole, l-propyl-Z- hydroxymethyl-S-nitroimidazole, l-n-butyl-2-hydroxymethyl-S-nitroimidazole, and Z-hydroxymethyl-S- nitroimidazole, the following compounds are respectively prepared: l-ethyl-2-formyl-5-nitroimidazole; lpropyl-2-formyl-5-nitroimidazole; l-n-butyl-2-formyl-5 -nitroimidazole; and 2-formyl-5-nitroimidazole.

EXAMPLE 4 l-( 2-Acetoxyethyl )-5-nitroimidazole 4.0 g. of 4(5)-nitroimidazole and 4.7 ml. of B-ethoxyethyl tosylate are heated together in a l70l75C. oil bath for 1 hour with occasional stirring until the mixture becomes homogeneous. The mixture is cooled to near room temperature and dissolved by agitating with amixture of about 50 ml. of chloroform and 50 ml. 4N ammonium hydroxide. The chloroform phase is extracted twice with 2N ammonium hydroxide and dried over sodium sulfate. Evaporation to dryness in vacuo gives a black syru'p which is filtered through 30 g. of basic alumina eluting with l,2-dichloroethanezether.

The very pale yellow band which comes through the Y column fairly rapidly is collected and evaporated in vacuo to give a yellow oil which crystallizes on seeding. The crude product is recrystallized from ether-hexane giving pale brown crystals of l-(2-ethoxyethyl)-5- nitroimidazole. I 57 mg. of the above product is heated at 100C. in 0.3 ml. concentrated sulfuric acid for one-half hour. The mixture is diluted with l.5 ml. water and heated an additional hourfThe solution is treated with charcoal, diluted with 1 ml. water and treated dropwise with 0.7 ml. of ll.7 N sodium hydroxide while cooled in ice. The crystalline precipitate which forms is filtered off, washed with water and air dried. This material is recrystallized from benzene and then with charcoal treatment from methanol-water giving l-(2-hydroxethyl)-5-nitroimidazole, m.p. l0l-l02C.

Acetylation of 15 g. of the latter product with g. of acetic anhydride in 30 ml. of pyridine at reflux for 20 minutes yields l-(2-aceotxyethyl)-5-nitroimidazole, m.p. 6l62C.

EXAMPLE 5 l-(2-Acetoxyethyl)-2-formyl-5-nitroimidazole A mixture of 24.25 g. of l-(2-acetoxyethyl)'-5- nitroimidazole prepared as in Example 4, g. of paraformaldehyde and 150 ml. of dimethylsulfoxide is heated in a sealed tube overnight at l0O-l50C. The dimethylsulfoxide is removed completely at reduced pressure, and the residue is dissolved in water and extracted with chloroform. The chloroform extract is dried and concentrated. The residue is dissolved in ethyl acetate, and thesolution is charged on a column of alumina. Elution with ethyl acetate and evaporation of the solvent yields l-(2'-acetoxyethyl)-2-hydroxymethyl-S-nitroimidazole, m.p. l38l45C.

This compound is then treated following the procedure of Example 1 with lead tetraacetate. After nitroimidazole-Z-hydroxamoylchloride.

lowing Examples which use the starting 2-formyl-l-substituted-S-nitroimidazoles of Example 3. After using thiscompound to form the desired cyclic-substituted I nitroimidazole, the acetate can be removed using hydrolysis to yield the desired l-(2'-hydroxyethyl)2- substituted-5-nitroimidazole.

The following Example, Example 6, shows the preparation of the nitrone of Formula Ill. Example 7 is the preparation of the hydroxyamoyl chloride of Formulall.

EXAMPLE 6 a-( lMethyl-5-nitroimidazolc-2-yl)-N-methylnitrone I -To a solution of l-methyl-2-formyl-5-nitroimidazole I prepared as in Example 3, (4.65 g., 0.03 mole) in ml. of methanol is added 2.5 g. (0.03 mole) of N- methylhydroxylamine hydrochloride CH NHOH'HCL.

The mixture is allowed to stand at room temperature for 4 hours. A precipitate forms which is recovered and dissolved in 40 ml. of water.-Solid sodium bicarbonate is added until the solution has a basic pH and a precipitate deposits again. After filtration and recrystallization from methanol, 1.8 g. of the products, a-( l-methyl-5-nitroimidazole-2-yl)-N-methylnitrone is recovered having a melting point of 180C. (with decomposition).

The corresponding a-( l-cthyl-5-nitroimidazol-2-yl)- N-methylnitrone, a-( l-propyl-5-nit'roimidazol-2-yl)-N- methylnitrone, and a-[ l-(2'-acetoxyethyl )-5- nitroimidazol-Z-yll-N-methylnitrone can be prepared in a similar fashion utilizing the respectively l-substituted-2-formyl-5-nitroimidazoles disclosed in Examples 3 and 5. The corresponding a-(l-methyl-S- nitroimidazol-Z-yl)-N-benzylnitrone can also be prepared using N-benzylhydroxylamine hydrochloride in the above reaction with l-methyl-2formyl-5- nitroimidazole.

EXAMPLE 7 l-Methyl-5-nitroimidazole-2-hydroxyamoylchloride water. The mixture is refrigerated overnight. Filtration and crystallization yielded a yellow crystalline material, having a melting point of 25 l252C. (dec.). This intermediate oxime product is dissolved in 50 ml. of

dimethylformamide at 0C. A solution of NOCl (13.1 g. a

in 200 ml. of dimethyl-formamide) is added dropwise with stirring. The mixture is stirred at 0C. for 15 minutes and 45 minutes at room temperature. It is quenched by pouring into 2,500 ml. of cold water, and the precipitate filtered, washed and dried. A sample is recrystallized from ethyl acetate and dried under vacuum. The product obtained has a melting point of l-l86C. and is identified as l-methyl-S- The corl-( 2 -acetoxyethyl)-5-nitroimidazole-2- l -ethyl-5-nitroimidazole-2- responding hydroxamoylchloride,

hydroxamoylchloride, l-n-butyl-5-nitroimidazole-2- hydroxamoylchloride, and 5-nitroimid-azoIe-Z-hydroxamoylchloride are prepared respectively from l-(2- acetoxyethyl)-2-formyl-5-nitroimidazole, l -ethyl-2- formyl-S-nitroimidazole, l-n-butyl-Z-formyl-S- nitroimidazole, and 2-formyl-5snitroimidazole prepared as in Examples 3. and 5.

The following Examples 8 to 35 all have the structural formula given. However, only the oxygen-containing ring is drawmWhe'n the NI is used, it is meant to be the Corresponding nitroimidazole-2-yl ring.

EXAMPLE 8 l-Methyl2-(2-methyl-5carboxymethyl-'isoxazolidinyl- 3-yl)-5-nitroimidazole EXAMPLE 9 l-Methyl-2-( 2-methyl-4,5-hexamethyleneisoxazolidinyl-3-yl)-5-nitroimidazole hydrochloride (Illa-CH2 CH2 I $112 oar-0H1 1.87 g. of the compound prepared in Example 6, a- (l-methyl--nitroimidaZol-2-yl)-N-methylnitrone, and 1.1 g. of cyclooctene are added in 30 ml. of'toluene. The mixture is refluxed for about 16 hours. At the end of thisperiod, the nitrone is dissolved. The reaction mixture, after filtering, is evaporated to a yellow oil. This'oilis purified by chromatographic techniques on silica gel with a benzenezchloroform-eluent. 2.5 g. of a clear yellow oil is, obtained. This oil is then mixed with ether containing dry hydrochloric acid to obtain 2.4 g.

of a crystalline material. After recrystallization from 2- propanol, a solid is obtained having a melting point of 193C. with decomposition. This solid is identified as l.- methyl-2-(2-methyl-4,5-hexamethylene-isoxazolidinyl- 3-'yl)-5-nitroimidazole hydrochloride. The analogous compound prepared using a-( l -methyl-5- methyl-2-( 2-b'enzyl-4,5-hexamethylene-isoxazolidinyl- 3-yl)-5-nitroimidazole hydrochloride. v

EXAMPLE l0 l-Methyl-2-( 2-methyl-5-carboxamido-isoxazolidinyl-3- yl)-5-nitroimidazole NI e A GHQ-N O LCONHz 5.52 g. of the nitrone prepared in Example 6 is refluxed with 2.34 g. of acrylamide in ml. of tetrahydrofuran. After 3 hours, an additional 1.0 g. of acrylamide in 40 ml. of tetrahydrofuran is added and refluxing continued. After 12 hours, the reaction mixture is cooled and filtered. After purification, 3.4 g. of the product, l-methyl-(2-methyl-5-carboxamido-isoxazolidinyl-3-yl)-5-nitroimidazole, having a melting point of 2l4-2l5C. (dec.) is recovered. The corresponding l-methyl-2-(2-benzyl-5-Carboxamido-isoxaz olindinyl-3-yl)-5-nitroimidazole is prepared using the N-benzylnitrone described in Example 6.

The product l-methyl-2-(2-methyl-5-carboxamidoisoxazolindinyl-3-yl)-5-nitroimidazole is then heated in an acidic solution to recover the hydrolysis product, I methyl-2-(2-methyl-5-carboxylic acid-isoxazolindinyl- 3-yl)-5-nitroimidazole. This latter product, after treating following the procedure of Example 13, yields 1- methyl-2-(2-rnethyl-5-amino-isoxozalindinyl-3-yl)5- nitroimidazole.

EXAMPLE ll l Methyl-2-[2-methyl-5-(N-methyl)-carboxamidoisoxazolidinyl-3-l-5-nitroimidazole 5.4 g. of the nitrone prepared in Example 6 is refluxed with 2.5 g. of N-methylacrylamide in 100 ml. of tetrahydrofuran. After 2 hours, an additional 1.0 g. of N-methylacrylamide in 40 ml. of tetrahydrofuran is added and refluxing continued. After 8 hours, the reaction mixture is cooled and filtered. After purification, the product, l-methyl-2-[2-methyl-5-(N-rriethyU-carboxamidoisoxazolidinyl-3-yl]-5-nitroimidazole, recovered. I v

In an analogous manner, using N-benzylnitrone and N-ethylacrylamide; or N-benzylnitrone and N-hexylacrylamide, the corresponding products, l-methyl-2- [Z-benzyl-S N-ethyl )-carboxamido-isoxozaolidinyl-3 yl]-5-nitroimidazole and l-methyl-2-[2-benzyl-5-(N- hexyl-carboxamido-isoxozalidinyl-3-yl]-5- nitroimidazole are'prepared.

identified as Also, when N,N-dimethylacrylamide or N-methyl-N- propylacrylamide are employed in the above reaction with the nitrone as prepared in Example 6, the products l-methyl-2-[ 2-methyl-5-(N,N-dimethyl )-carboxamidoisoxozalidinyl-3-yl]-5-nitroimidazole and l-methyl-2-[ 2-methyl-5(N-methyl-N-propyl)-carboxamido-isoxozalidinyl-3-yl]-5-nitroimidazole are formed.

EXAMPLE l2 l-Methyl-2-( S-carboxyethylisoxazol-3 -yl )-5- nitroimidazole l e 0 amon ethanol, the product isobtained which has a melting point of ll4-ll5C. This product is identified as lmethyl-2-( 5-carboxyethylisoxazol-3-yl)-5- nitroimidazole.

EXAMPLE 13 1-Methyl-2-(5-carboxamido-isoxazol-3-yl)-5- nitroimidazole C ONHz 3 g. of the compound prepared in Example 12 is dissolved inhot methanol. The solution is saturated with ammonia. A precipitate is formed and the mixture is cooled by placing in the refrigerator. After filtration and purification, the pure product having-a melting point of 235238C. is recovered. This productis l-methyl-2-( 5-carboxamido-isoxazol-3- yl)-5-nitroimidazole.

EXAMPLE 14 l-Methyl-2r(5-aminoisoxazol-3-yl)-5-nitroimidazole nitroimidazole. are dissolved in 30 ml. of a 10% HCl solution, and the mixture heated to reflux. After 30 minutes, the reaction is terminated and the product, 1- methyl-2-(5-carboxylic acid-isoxazol-3-yl)-5- nitroimidazole, is obtained.

1.5 g. of the acid prepared above are refluxed in oxalyl chloride (25 ml.) until a clear solution is obtained, after about 6 hours. Excess reagent is removed under vacuum. The product, l-methyl-2-(5-carboxylic acid chloride-isoxazol-S-yl)-5-nitroimidazole is dissolved in 50 ml. acetone. A solution of sodium azide (0.4 g. of NaN in 5 ml. of water is added all at once. After stirring for l5 minutes, an additional 100 ml. of water is added and stirring continued for another 15 minutes. The product is l-methyl-2-(5-carboxylic acid azideisoxazol-3-yl)-5-nitroimidazole. 1.4 g. of the latter is dissolved in 60 ml. of benzene and refluxed for 3 hours. 10 ml. of concentrated HCl are (25 added and refluxing continued for one-half hour. The reaction is diluted with chloroform and made basic. The dried organic phase yielded 0.5 g. of the product, l-methyl-2-(5- aminoisoxazol-3-yl)-5-nitroimidazole, m.p. l80-l85 C.

0.25 g. .of l-methyl-2-(5-aminoisoxazol-3-yl)-5- nitroimidazole, prepared above, are dissolved in 20 ml. of dimethylformamide. 0.16 g. of methyl iodide are added, and the reaction mixture is heated to 80 for 1 hour. The solvent and unreacted reagents are removed, and the product recrystallized. The product is 1- methyl-2-(5-aminomethyl-isoxazol-3-yl)-5- nitroimidazole.

' The product prepared above is treated in a similar fashion with hexyl chloride in dimethylformamide for 2 hours. The recrystallized product is identified as 1 methyl-2-(5-aminoethylhexylisoxazol-3-yl)-5- nitroimidazole.

EXAMPLE l5 l-Methyl-2-( 4,5,6,7-tetrahydrocyclohex[d ]isoxazol-3'- yl )-5-nitroimidazole CH2 I NI CH2 H2 \0 cm To a suspension of 2.04 g. of the hydroxamoyl chloride prepared in Example 7 in 30 ml. of tetrahydrofuran at 0C. is added a solution of triethylamine and l-morpholino-3,4,5,6- tetrahydrobenzene (1.01 g. of triethylamine and 1.67 g. 'of the morpholino compound). The mixture is stirred 15 minutes at 0C. and one-half hour at room temperature. The tetrahydrofuran is evaporated. The residue is dissolved in dichloromethane and is washed with sodium bicarbonate solution. The organic phase is dried and evaporated to a yellow oil. After treatment with .diethyl ether, a crystalline productis obtained. A sample recrystallized from methanol has a melting point of l53l56C. This product is an intermediate in the synthesis and is a A -isoxazoline compound with a morpholino substituent. It is identified as l-methyl-2- (4,5-tetramethylene-5-morpholino-A -isoxazolindin-3- yl)-5-nitroimidazole, mp. 155C.

This latter morpholino compound l g.) is dissolved in concentrated sulfuric acid (I00 ml.) and heated on a steam bath for Bi hours. The yellow reaction mixture is poured onto ice to quench. After filtration, a crude product isobtained. lt is recrystallized from methanol and yields 4.5 g. of a product identified as l-methyl-2- (4,5,6,7-tetrahydrocyclohex[d]isoxazol-3-yl)-5- nitroimidazole,'having a melting point of l61-l62C.

The following Examples 16 through 36 relate to the preparation of the A -isoxazoline. It will be clear to one skilled in the art that, although the l-vmethyl derivatives are prepared, the other loweralkyl, acetoxyethyl, and unsubstituted derivatives can be prepared from'the corresponding hydroxamoyl chloride compounds in Example 7. 1

EXAMPLE l6 l-Methyl-2-(S-carboxymethyl-A -isoxazolin-3-yl)-5- v nitroimidazole ganic layer is evaporated and the residual yellow oil is crystallized. The product is identified as l-methyl-2-(5- carboxymethyl-A -isoxazolin 3 -yl )-5 -nit'roimidazole, and has a melting point of l09-l 10C.

'. xAMPLE'n 1-Methyl-2-(5-carboxamido-A -isoxazolin-3-yl)-5- nitroimidazole v I i Locum,

This latter compound can be treated. following the procedure of Example 14 to yield 2(5-amino-A -isoxazolin-B-yl)-5-nitroimidazole.

EXAMPLE l8 1-Methyl-2-(5-phenyl-A -isoxazolin-B-yl)-5- nitroimidazole 2.04 g. of the hydroxamoylchloride prepared in Example 7 are dissolved in 40 ml. of tetrahydrofuran. One gram of styrene is added and the solution is kept at 0C. while a solution of triethylamine tetrahydrofuran (1.01 g. in 10 ml.) is added. The mixture is stirred 15 minutes at 0C. and l hour at room temperature. After filtering and removing the excess solvent, the residue is taken up in chloroform and washed with a dilute solution of sodium bicarbonate. Evaporation of the dried extract yields a yellow oil-which recrystallizes from methanol as a pale yellow crystalline material. This material has a melting point of l33l34C. and is identified as lmethyl-2-(5 phenyl-A -isoxazolin-3-yl)-5- nitroimidazole.

EXAMPLE l9 l-Methyl 2 t4,5- cyclodimethylsulfone-A -isoxazolin-3- yl)-5-nitroimidazole 0.408 g. of the hydroxamoylchloride preparedin Example f7-are dissolved inz8 ml. of tetrahydrofuran containing 0.5 grams of dihydrothiophene l,l-dioxide at 0C. To this solution is added dropwise with stirring a 0.202 g. solution of triethylamine in 2 ml. of tetrahydrofuran. The' mixture is stirred for 15 minutes at 0C. and one hour at room temperature. After filtering and removing the solvent, the residue is treated with chloroform and washed with sodium bicarbonate v The compound preparedin Example 16 is dissolved in methanol (119mg. in l0 ml.). Ammonia is bubbled through the solution until a precipitate formed. The mixture is filtered after 1 hour and purification and recrystallization yield 95 mg. of the product, l-methyl- 2-(5-carboxarnido-A isoxazolin-3-yl) 5- nitroimidazole, having a melting point-of 238239 C. v

yl)-5-nitroimidazole, having a melting point of-20820 EXAMPLE 2o l-methyl-2-( 35,5 ,6,7a-tetrahydro-4l l-pyrano[ 3 ,Z-d isoxazol-3-yl )-5-riitroimidazole Following the same general procedurc of Examples EXAMPLE 24 16 through l9, the hydroxamoylchloride prepared as in I Example 7 is reacted with dihydropyran at C. The product, after recrystallization, is identified as lmethyl-2-( 3a,5 ,6,7a-tetrahydro-4H-pyrano[ 3 ,2-d l- 5 isoxazol-3-yl)-5-nitroimidazole having a melting point TUA l -M'ethyl-2-( i,5-cis-dimethyl-A -is0xazolin-3-yl)-5- nitroimidazole of l40-l42C.

43113 EXAMPLE 2l 0 l0 l-Methy-2-(3-a,4,6,6-a-tetrahydro-4,6-dixo-4-H- py'rrolo[3,4-d1-A -isoxazol-3-yl)-5-nitroimidazole A 7 7 l v v 7 Following the same general procedure of Examples I I I r 0 16 through 19, the hydroxamoylchloride prepared as in Example 7 is reacted with cis-2-butene. The product, NI after recrystallization, is identified as l-methyl-(4,5- N NH cis-dimethyl-A -isoxazolin-3-yl-5-nitroimidazole, hav- C ing a melting point of 8384C.

ll g 20 EXAMPLE Following the same general Procedure of Examples l'Methyl 2 (45'tran.S i e.:1hyl lA'2'lSOxaZolm 3-yl)6- l6 through 19, the hydroxamoylchloride prepared as in am 6 Example 7 isreacted with maleimide. The product, 25 after recrystallization, is identified as l-methyl-2-(3 isoxazol-3-yl)-5-nitroimidazole, having a melting point l J of 259C. (dec.). g \0 -OH:

EXAMPLE 22 Following the same general procedure of Examples 16 through l9, the hydroxamoylchloride prepared as in Example 7 is reacted with trans-Z-butene. The product,

after recrystallization, is identified as l-methyl-2-(4,5-

trans-dimethyl-A -isoxazolin-ii-yl)-5-nitroimidazole, having a melting point of6567C. I

l-Methyl-2-( 5-Hexyl-A -Isoxazolin-3-Yl 5 ,Nitroimidazole iomomomcmomom EXAMPLE 2 EXO-2-(3-a,4,5,6,7,7a-hexahydro-4,7-methano-l,2-

benzisoxazol-3-yl l -methyl-5-nitroimidazole Following the same general procedure of Examples H 16 through 19, the hydroxamoylchloride prepared as in Example 7 is reacted with octene-l. The product, after NI l 2 recrystallization, is identified as l-methyl-2-(5-hexyl- N 2 (3H2 A -isoxazolin-3-yl)-5-nitroimidaz0le, having a melting 0 l l point of 5 1C.

EXAMPLE 23 Following the same general procedure of Examples 16 through 19, the hydroxamoylchloride prepared as in Example 7 is reacted with norbornene. The product, after recrystallization, is identified as exo-2- (321,4,5,6,7,7a-hexahydro-4,7-methano-l,Z-benz-isoxazol-3-yl)- l -methyl-5-nitroimidazole, having -a melting l J point of l24-l25C.

EXAMPLE 27' 1-methyl-2-(A -isoxazolin-3-yl )-5-nitroimidazole l-Methyl-2-( 5-be nzoyl-3a,5 ,6,6a-tetrahydro-4H- pyrrolo[3,4-dl-isoxazol-3-yl)-5-nitroimidazole Following the same general procedure of Examples 16 through 19, the hydroxamoylchloride prepared as in CH Example 7 is reacted with ethylene. The product, after NI recrystallization, is identified as l-methyl-2-(A -isoxazolin-3-yl)-5-nitroimidazole, having a melting point of N Following the same general procedure of Examples 16 through 19, the hydroxamoylchloride prepared as in Example 7 is reacted with N-benzoyl-2,5-dihydropyriole. identified tetrahydro-4H-pyrrolo[ 3 ,4-d]-isoxazol-3 -yl nitroimidazole, having a melting point of l53-l 55C.

The product, after recrystallization, is

as l-methyl-2-(5-benzoyl-3a,5,6,6a 5

Following the same general procedure of Examples 16 through 19, the hydroxamoylchloride prepared as in Example 7 'is reacted with trans-cyclooctene. The product, after recrystallization, is identified as trans-lmethyl-2-[ 3a,4,5 ,6,7 ,8 ,9,9a octahydrocyclooc,t[ d isoxazol-3 yl)-5 nitroimidazole, having a melting point of l06-l09C.

EXAMPLE 29 l-Methyl-2-( 3a,5 ,6,6a-Tetra'-Hydro-4H-Cyclopent[ d lv lsoxazol-3-Yl)-5Nitroimidazole I CH2 cHz 1 1 g I C 2 a 40 Following the same general procedure of Examples 16 through 19, the hydroxamoylchloride prepared as in Example 7 is reacted with cy clopentene. The product, after 'recrystallization, isidentified as l -methyl-2 (3 a,5,6;6a-tetrahydro-4H-cyclop'ent[dl-isoxazol-3 yl)-5- nitroimidazole EXAMPLE30 408 mg. of the hydroxamoylchloride prepared in Example 7 and 224 mg. of cyclooctene are added to 6 ml. of toluene and refluxed for 14 hours. The mixture is cooled and passed through a" thin-layer chromatographiccolumn of-lO g. of silica gel, using benzene as 20' I an eluent. The fractions containing the product are A reduced to yield a yellow crystalline material. This product is recrystallized from hexane, yielding the product, l-met hyl-2-( 3a,4,5,6,7,8,9,9a-0ctahydrocyclooct[d]-isoxazol-3 -yl)-5-nitroimidazole, having a melting point of 1 to 115C.

EXAMPLE 3i l'-Methyl-2 3a,4,5,6,7,'7a-hexahydro-l ,2-benzisoxazol-S-yl 5-nitroimidazole Following the same procedure as in Example 30, the hydroxamoylchloride prepared as in Example 7 is reacted with cyclohexene. The product, 2-,( 3a,4,5,6,7,'7 a-hexahydro-l ,2 benz-isoxazol-3-yl )-5-nitroimidazole has a melting point of H 9-l 2 lC.

EXAMPLE 32' l-Methyl-cis-2-( 3a,5,6,7,8,8a-hexahydro-4H- cyclohept[ d] isoxazol-3-yl ).-S-nitroimidazole Following the same procedure as in Example 30, the vhydroxamoylchloride prepared as in Example 7 is reacted with cycloheptene. Theproduct, l-methyl-cis- 2-(3a,5,6,7;8,8a-hexahydroF4l-l-cyclohept[dl-isoxazol- 3-yl')-5-nitroimidazole, having a melting point of 93-95C; v

' EXAMPLE 33 Gila-CH2 l- Methyl-trans-2-(3a,4,5,6;7,8,9,l0,l1,12,13,13adodecahydrocyclododecid-isoxazoLB-yl )-5-' nitroimidazole Following the same procedure as in Example 30, the hydroxamoylchloride prepared as .in Example 7 is reacted with cyclododecene, Theproduct, l-methyltrans-2'-(3a,4,5,6,7,8,9,l0,1l,l2,l3,,l3a-dodecahydrocyclododec[d]-isoxazol-3-yl)-5-nitroimidazole; having a melting point of 1 2 1-1 22 c.

EXAMPLE 34 Following the same procedure as in Example 33, the

hydroxamoylchloride is reacted with 6-amino-2-hexl-Methyl-2-( trans-4,5-dipropyl-A -isoxazolin-3-yl )-5- enoic acid lacmm:

nitroimidazole IIC-CII- -Cll L c NI c1\ 1 113 Cm 11 C-N N\ 01-12 g H 0 car CH;

i The product, l-methyl-2-(4,5-hexano-e-lactam-A isoxazolin-B-yl)-5-nitroimidazole is recovered.

We claim: 15 l. A 1,2-disubstituted-5-nitroimidazole having the following structure 6.12 g, of the hydroxamoylchloride prepared as in Example 7 is refluxed with 3.4 g. of trans-4-octene for 18 hours. The reaction mixture is then worked up following a similar procedure as in Example 30, The product obtained, l-methyl-2-(trans-4,5-dipropyl-A 7-,

isoxazolin-3-yl)-5-nitroimidazole, has a melting point N of 34-36C. 20 I H aN LR, EXAMPLE 3s N R Rs l-Methyl-2-(trans-4,5-d1ethyl-A -isoxazolm-3-yl)-5- 0 L nitroimidazole i CHCHa wherein R is hydrogen, lower alkyl having 1-6 carbon I atoms, or -CH,CH OH and R and R together (311,011, represent a ring structure having the following struc- 0 ture -CH where n equals an integer of from 3l0;

Following the same procedure as in Example 34, the

hydroxamoylchloride is reacted with trans-3-hexene. L The product, 1-methyl-2-(trans-4,5-diethyl-A -isoxazolin-S-yl)-5-nitroimidazole, has a melting point of 6667C.

EXAMPLE 40 where in equals an integer of from l-3; and where n equals an integer of from 1-2. 2. The compound of claim 1 which is exo-2- (3a,4,5,6,7,7a-hexahydro-4,7-methano-1,2-benz-isoxazol-3-yl)- l -methyl-5-nitroimidazole.

l-Methyl-2-(4,5-hexano-e-lactam-A -isoxazolin-3-yl)- 5 -nitroimidazole NI 3. The compound l-methyl-2-(3a,4,5,6,7,8,9,9a-oci 2 tahydrocyclooct[d]3-yl)-5-nitroimidazole.

4. The compound l-methyl2-(3a,4,5,6,7,7a-hexg ahydro-l ,Z-benz-isoxazol-S-yl )-5-nitroimdazole. 0 l

Claims (3)

1. 2. The compound of claim 1 which is exo-2-(3a,4,5,6,7,7a-hexahydro-4,7-methano-1,2-benz-isoxazol-3-yl)-1-methyl -5-nitroimidazole.
2. 3. The compound 1-methyl-2-(3a,4,5,6,7,8,9,9a-octahydrocyclooct(d)-isoxazol-3-yl)-5 -nitroimidazole.
3. 4. The compound 1-methyl2-(3a,4,5,6,7,7a-hexahydro-1,2-benz-isoxazol-3-yl)-5-nitroimdazole.