P. V. Kurman

Polychlorobutanoic and Polychlorobutenoic Acids in the Synthesis of Polyfunctional Derivatives

From 3,4,4-trichloro-3-butenoic acid 3,3,4,4,4-pentachlorobutanoic, 3,4,4,4-tetrachloro-2-butenoic, and 2,3,4,4-tetrachloro-3-butenoic acids were synthesized. By Friedel &-Krafts reaction from 3,4,4-trichloro-3-butenoyl and 3,3,4,4,4-pentachlorobutanoyl chlorides with aromatic hydrocarbons the corresponding aryl chloroalkyl ketones were prepared. It was established that dehydrochlorination of 2,2,3,3,3-pentachloropropyl phenyl ketone with aqueous alkali under conditions of the phase-transfer catalysis at the molar ratio of reagents ketone:KOH:triethylbenzylammonium chloride equal to 1:4:0.05 involved the cleavage of two HCl molecules and resulted in 3,3,3-trichloro-1-propynyl phenyl ketone.

The Synthesis of Isoxazolyl- and Isothiazolylcarbamides Exhibiting Antitumor Activity

Accessible 5-phenyl(p-tolyl)isoxazol-3-carboxylic, 4,5-dichlorothiazol-3-carboxylic and 5-(benzylsulfanyl)-4-chlorothiazol-3-carboxylic acids were converted via a series of cascade transformations into the corresponding (1,2-azolyl)-3-carbonyl azides whose reaction with slightly basic aryl(heteryl)amines led to generation of 1-(1,2-azolyl)-3-aryl(heteryl)carbamides. To obtain isoxazolyl(isothiazolyl)carbamides containing the residues of highly basic amines, (1,2-azolyl)-3-carbonyl azides were preliminary transformed into aryl (1,2-azol-3-yl)carbamates by the action of phenol or 4-fluorophenol. Carbamates then were introduced into reaction with aliphatic or heterocyclic amines. Some of the obtained compounds and their precursors show high antitumor activity and are capable to increase the effect of cytostatic drugs applied in the medical practice.

Synthesis and deborination of polyhalo-substituted ortho-carboranes

Tetraiodo-1,2-dicarba-closo-dodecaborane and 9-bromo-8,10,12-triiodo-1,2-dicarba-closo-dodecaborane were synthesized by oxidative iodination of 1,2-dicarba-closo-dodecaborane and 9-bromo-1,2-dicarba-closo-dodecaborane, respectively, in AcOH using a mixture of nitric and sulfuric acid as an oxidant of iodine. The intermediates in the ortho-carborane iodination were identified. By the action of elemental bromine on 9-iodo-1,2-dicarba-closo-dodecaborane in the presence of aluminum chloride catalyst 9-iodo-8,10,12-tribromo-1,2-dicarba-closo-dodecaborane was obtained. Deborination of the synthesized substances with an alcohol solution of KOH led to formation of 1,5,6,10-tetraiodo-5-bromo-1,6,10-triiodo- and 5-iodo-1,6,10-tribromo-7,8-dicarbaundecaborates methylammonium salts.

An improved synthesis of [26-(2)H3]castasterone.

Commercially available epicastasterone has been employed as a starting material for the preparation of [26-(2)H3 ]castasterone. The chemical synthesis has been realized in 13 chemical steps and 4.6% total yield. The target compound is intended to be used as internal standard for the quantitative analysis of brassinosteroids.

Synthesis of iodinated meta-carboranecarboxylic acids

A new method for introduction of one and two iodine atoms into the meta-carborane fragments containing carboxy groups at the core carbon atoms C1/C2 was developed. Reaction proceeded in acetic acid at heating in the presence of concentrated nitric and sulfuric acids.

Synthesis and reactions with N-nucleophiles of 1-(thien-2-yl)- and 1-(4-hydroxyphenyl)-3,4,4-trichloro-3-buten-1-ones

Acylation of thiophene and phenol with 3,4,4-trichloro-3-butenoyl chloride afforded the corresponding 1-(thien-2-yl)- and 1-(4-hydroxyphenyl)-3,4,4-trichloro-3-buten-1-ones, whose reaction with amines led to the formation of 3-amino-1-(thien-2-yl, 4-hydroxyphenyl)-4,4-dichloro-2-buten-1-ones The heterocyclization of the initial ketones into pyrazole structure was not observed, and the reaction with hydrazine hydrate provided bispyrazole products, N,N′-bis(5-thien-2-yl)- and N,N′-bis[5-(4-hydroxyphenyl)-1H-pyrazol-3-ylmethylene]hydrazines.

Synthesis of 5-substituted 3-[5-(2,5-dimethylphenyl)-1,2-oxazol-3-yl]-1,2,4-oxadiazoles

Abstract5-(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.

Synthesis of 4,5-dichloro-3-cyanoisothiazole and its functional derivatives

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.

Synthesis of 3-substitued 5-(2-thienyl)isoxazoles

The reaction of 3,4,4-trichloro-1-(2-thienyl)but-3-en-1-one with hydroxylamine gave 3-hydroxyiminomethyl-5-(2-thienyl)isoxazole which was converted into 5-(2-thienyl)isoxazole-3-carbonitrile by the action of acetic anhydride in pyridine. 5-(2-Thienyl)isoxazole-3-carbonitrile reacted with hydroxylamine to produce the corresponding amide oxime. Heterocyclization of its O-acyl derivatives in acetic acid afforded 5-substituted 3-[5-(2-thienyl)isoxazol-3-yl]-1,2,4-oxadiazoles.

Synthesis of mono-and 1,1′-bis(3,4,4-trichlorobut-3-enoyl)-ferrocenes and 3,4,4-trichlorobut-3-enoylcymantrene

Friedel-Crafts acylation of ferrocene and cymantrene with 3,4,4-trichlorobut-3-enoyl chloride gave the corresponding trichloroallyl ferrocenyl and cymantrenyl ketones. The reaction with ferrocene involved either one or both cyclopentadienyl fragments, depending on the reactant ratio. The acylation of acetylferrocene with 3,4,4-trichlorobut-3-enoyl chloride afforded 1-acetyl-1′-(3,4,4-trichlorobut-3-enoyl)ferrocene.