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Methyl 5-hydroxy-4-oxo-4 H-pyran-2-carboxylate was synthesized by esterification of methanol with comenic acid under acidic catalysis. The obtained ester was alkylated with 3-(chloromethyl)-5-phenylisoxazole and 4,5-dichloro-3-(chloromethyl)isothiazole to afford corresponding conjugates containing isoxazole and isothiazole moieties which then were transformed into water-soluble Li-salts. During the bioassays of synthesized isoxazole and isothiazole derivatives of comenic acid in mixtures with first-line antitumor drug Temobel (Temozolomid) used in brain tumors chemotherapy, a synergetic effect was observed.

Butane-, phenylmethane-, and benzenethiols reacted with 4,5-dichloro-3-trichloromethyl-1,2-thiazole in the presence of sodium ethoxide to give the corresponding 5-alkyl(aryl)sulfanyl-4-chloro-3-trichloromethyl-1,2-thiazoles. The reaction of 4,5-dichloro-1,2-thiazole-3-carboxylic acid with the same thiols under similar conditions resulted in the formation of sodium 4,5-dichloro-1,2-thiazole-3-carboxylate, while in the presence of pyridine 5-alkyl(aryl)sulfanyl-4-chloro-1,2-thiazole-3-carboxylic acids were obtained.

The reaction of 1-aryl-3,4,4-trichlorobut-3-en-1-ones with semicarbazide hydrochloride in the presence of sodium acetate is accompanied by prototropic allylic rearrangement, leading to the formation of two isomeric products, semicarbazones of the initial ketones and 1-aryl-3,4,4-trichlorobut-2-en-1-one semicarbazones. The latter undergo heterocyclization in the presence of triethylamine to give the corresponding 3-aryl-5-dichloromethyl-1H-pyrazole-1-carboxamides.

2-(2-Naphthyl)thiophene was synthesized by condensation of 3-chloro-3-(2-naphthyl)prop-2-enal with sulfanylacetic acid. A modified procedure was proposed for the synthesis of 2-(2-naphthyl)-and 2-(2-naphthyl)-6-nitroquinolines from 3-chloro-3-(2-naphthyl)prop-2-enal.

β-Naphthyl-substituted derivatives of pyrazole, benzodiazepine, isoxazole, and pyrimidine were synthesized by reactions of (Z)-3-chloro-3-(2-naphthyl)propenal with hydrazine, o-phenylenediamine, hydroxylamine, and formamide, respectively.

By reaction of Z-3-(2-naphthyl)-3-chloro-2-propenal and aromatic amines 1-(2-naphthyl)-3-iminoaryl-1-propenylarylamines were prepared which at heating in the glacial acetic acid afforded the corresponding 2-(2-naphthyl)quinolines.

The most recent achievements in the chemistry of isothiazoles are generalised and systematised. The main applications of isothiazole derivatives are surveyed. The bibliography includes 293 references.

By alkylation of vanillin with 4,5-dichloro-3-chloromethylisothiazole the corresponding ether was synthesized. The latter was then reacted with p-toluidine to afford the corresponding azomethine. During the bioassays of synthesized isothiazolic derivatives of vanillin in mixtures with insecticides (imidacloprid and α-cypermethrin) a strong synergetic effect was observed.

We used 5-arylisoxazole-3-carbonitriles and 4-R-5-chloroisothiazole-3-carbonitriles to prepare the corresponding (5-arylisoxazol-3-yl)- and (4-R-5-chloroisothiazol-3-yl)-1,2,4-triazoles, -tetrazoles, and -1,3,4-oxadiazoles. The obtained bis-heterocycles along with some of the intermediate monocyclic azoles formed palladium complexes that were highly active Suzuki reaction catalysts in aqueous and aqueous-alcohol media.

Acylation of benzene and toluene with 5-phenyl- and 5-(p-tolyl)isoxazole-3-carbonyl chlorides gave 5-phenyl(or p-tolyl)isoxazol-3-yl phenyl(or p-tolyl)ketones which were reduced to the corresponding alcohols with sodium tetrahydridoborate in propan-2-ol. Selective reduction of the carboxy group in 4,5-dichloroisothiazole-3-carboxylic acid was achieved by the action of BH3, and the aldehyde group in 4-formyl-2-methoxyphenyl 5-arylisoxazole-3-carboxylates and 4,5-dichloroisothiazole-3-carboxylates was reduced to hydroxymethyl group with sodium triacetoxyhydridoborate in benzene. Acylation of the resulting hydroxymethyl derivatives with 5-arylisoxazole- and 4,5-dichloroisothiazole-3-carbonyl chlorides afforded the corresponding esters containing two azole fragments in their molecules.

By reaction of Z-3-(2-naphthyl)-3-chloro-2-propenal with semicarbazide hydrochloride and thiosemicarbazide the corresponding semicarbazone and thiosemicarbazone were obtained that underwent a heterocyclization into a pyrazole system with elimination of amide moieties and with migration of the naphthyl fragment into the position 4 of the pyrazole ring. The alkylation of 4-(2-naphthyl)pyrazole synthesized with 2-nitropentachloro-1,3-butadiene afforded 1,1-bis[4-(2-naphthyl)-pyrazol-1-yl]-2-nitrotrichloro-1,3-butadiene.

Reactions of 4,5-dichloroisothiazol-3-ylcarbonitrile with methylmagnesium iodide and ethylmagnesium bromide afforded the corresponding alkyl (4,5-dichloroisothiazol-3-yl) ketones. The reaction of (4,5-dichloroisothiazol-3-yl) methyl ketone with morpholine and piperidine provided 5-morpholino-(piperidino)-substituted derivatives, by the action of sodium borohydride in 2-propanol the keto group was reduced to alcoholic hydroxy group. The bromination of (4,5-dichloroisothiazol-3-yl) methyl ketone with elemental bromine gave bromomethyl (4,5-dichloroisothiazol-3-yl) ketone, whose reaction with thiourea resulted in 2-amino-4-(4,5-dichloroisothiazol-3-yl)thiazole.

Thienyl trichloroallyl ketone (I), a synthetic equivalent of β-chlorovinyl ketones, reacts with hydroxylamine to an intermediate dichloromethyl-substituted isoxazole which upon reaction with a second hydroxylamine molecule affords the hydoxyiminomethyl-substituted isoxazole (II).

From substituted benzaldehydes of the vanillin series and 4-methyl-1,2-phenylene diaminein the presence of sodium hydrogen sulfite in DMF medium at 80°C new functionally substituted 2-[3-alkoxy-4-(hydroxy, alkoxy, acyloxy)phenyl]-5-methyl-1H-benzimidazoles were obtained in preparative yields.

The new, functionally substituted title compounds (III) (35 examples) are obtained by reaction of phenylenediamine (I) with aldehydes of the vanillin series, their ethers and esters in the presence of sodium hydrogensulfite.

The main methods of the synthesis of nitrobutadienes and their halogen derivatives, which are multipurpose electrophiles, are surveyed. The literature data on their chemical transformations are generalised, the possibilities for the preparation of new polyfunctional derivatives of different classes on the basis of nitro- and halo-nitrobutadienes that have been inaccessible earlier are demonstrated. The bibliography includes 112 references.

The published data on the methods for the preparation of mixed halogenobuta-1,3-dienes are generalised and systematised with a special emphasis on compounds of high practical value. Chemical transformations of mixed halogenodienes are considered and broad possibilities of the use of these compounds for the synthesis of various valuable, but difficultly accessible polyfunctional products are demonstrated. The bibliography includes 115 references.

Peroxyacetylenic menthol derivatives were synthesized by reaction of l-menthone with lithium 3-(tert-alkyldioxy)-3-methyl-1-butynides and were converted into the corresponding acetates by treatment with acetic anhydride. The thermal stability of the products was estimated by derivatography and quantum-chemical calculations.

The reactions of 4-ethoxy-2-(2,3,3-trichloro-1-nitro-2-propenylidene)benzazetine with methyl- and phenyllithium at a ratio of 1:2 result in replacement of one chlorine atom and formation, respectively, of 4-ethoxy-2-(2,3-dichloro-3-methyl-1-nitro-2-propenylidene)benzazetine and 4-ethoxy-2-(2,3-dichloro-1-nitro-3-phenyl-2-propenylidene)benzazetine in 45 and 52% yield. With excess phenyllithium (reactant ratio 1:5), a mixture of products is formed due to replacement of one, two, and three chlorine atoms by phenyl groups. An analogous reaction with methyllithium is nonselective.

5-(2,5-Dimethylphenyl)-1,2-oxazole-3-carbaldehyde oxime reacted with acetic anhydride in pyridine to give 5-(2,5-dimethylphenyl)-1,2-oxazole-3-carbonitrile which was converted into the corresponding amide oxime by treatment with hydroxylamine. O-Acyl derivatives of N′-hydroxy-5-(2,5-dimethylphenyl)-1,2-oxazole-3-carboximidamide underwent heterocyclization into 5-substituted 3-[5-(2,5-dimethylphenyl)-1,2-oxazol-3-yl]-1,2,4-oxadiazoles on heating in acetic acid.

4,5-Dichloro-1,2-thiazol-3-amine was synthesized starting from accessible 4,5-dichloro-1,2-thiazole-3-carbonyl azide and -3-carboxamide via Curtius and Hofmann rearrangements, respectively. The procedure involving Curtius rearrangement was found to be more advantageous from the preparative viewpoint.

Reaction between 4-formyl-2-methoxyphenyl 4,5-dichloroisothiazole-3-carboxylate with various aromatic amines led to azomethins 2-7 formation. By treatment of azomethins 2-7 with sodium triacetoxyborohydride corresponding amines 8-11 were obtained. During the bioassays of new vanillin derivatives in mixtures with insecticides remarkable synergetic effect was discovered.

By treating with phosphorus pentoxide the 4,5-dichloroisothiazole-3-carboxamide 4,5-dichloro-3-cyanoisothiazole was synthesized whose reactions with piperidine, phenyl-and benzylthiols occurred with replacement of the chlorine atom in the position 5 by the residue of the corresponding nucleophile. Reactions with sodium thiobytylate and also with sodium methylate in methanol led to the formation both of the products of chlorine substitution by BuS or MeO groups respectively and of addition products of methanol to the cyano group. The reaction of butanethiol with cyanoisothiazole in 2-propanol in the presence of sodium 2-propylate was more selective and resulted in the replacement of the chlorine atom in the position 5 by the residue of the butanethiol.

Reactions of 2-bromo-1-phenyl- and 2-bromo-1-(4-methylphenyl)-3,4,4-trichlorobut-3-en-1-ones with morpholine and diethylamine are accompanied by prototropic allylic rearrangement, leading to 3-amino-1-aryl-2-bromo-4,4-dichlorobut-2-en-1-ones as mixtures of E and Z isomers. The title compounds react with hydrazine, hydroxylamine, and thiourea to give the corresponding 5-aroyl-4-methoxypyrazoles, 3-aryl-5-hydroxyiminomethyl-4-methoxyisoxazoles, and 2-amino-4-aryl-5-trichlorovinylthiazoles.