GB759810A - Thiazole derivatives - Google Patents

Abstract

The invention comprises compounds of the formula <FORM:0759810/IV(a)/1> where R is alkyl, substituted alkyl or aryl, and Q represents the atoms necessary to complete a thiazolone or thiazolidone ring. Preferred compounds are 2-thio-4-thiazolidones (rhodanines) of the formula <FORM:0759810/IV(a)/2> where R2 is alkyl, substituted alkyl, cycloalkyl or alkenyl of 1-7 carbon atoms, and 2-thio-5-thiazolones of the formula <FORM:0759810/IV(a)/3> where R3 is alkyl or substituted alkyl of 1-7 carbon atoms. R is preferably C1-C12 alkyl or an aryl radical of the benzene series. The compounds are made by reacting the corresponding alkoxy-ethylidene compounds with RSH in the presence of zinc chloride and dry hydrogen chloride; an inert diluent is preferably used. Examples show the preparation of 3-carbethoxymethyl - 5 - (a -ethylthioethylidene)-2 - thiothiazolid - 4 - one, 3 - carbethoxymethyl-5 - (a - isopropylthioethylidene) - 2 thiothiazolid - 4 - one, 3 - carbethoxymethyl - 5 - (a - n - butylthioethylidene) - 2 - thiothiazolid - 4 - one, 3 - benzyl - 5 - (a - ethylthioethylidene) - 2 - thiothiazolid - 4 - one, 3 - allyl - 5 - (a - p - tolylthioethylidene) - 2 - thiothiazolid - 4 - one, 3 - carbethoxy - methyl - 5 - (a - p - tolylthioethylidene) - 2 - thiothiazolid - 4 - one, 2 - ethylthio - 4 - (a - ethylthioethylidene) - thiazol - 5 - one, 2 - benzylthio - 4 - (a - ethylthioethylidene)-thiazol - 5 - one, 3 - cyclohexyl - 5 - (a - ethylthioethylidene) - 2 - thiothiazolid - 4 - one, 3 - carbethoxymethyl - 5 - (a - benzylthioethylidene) - 2 - thio - thiazolid - 4 - one, 3 - carbethoxymethyl - 5 - (a - n - octylthioethylidene) - 2 - thiothiazolid - 4 - one and 3 - ethyl - 5 - (a - ethylthioethylidene) - 2 - thiothiazolid - 4 - one. It is stated that in some cases the compounds are obtained in small quantities by condensing the thiazolones or thiazolidones with alkyl trithio-orthoacetates. The products exist as cis and trans isomers. R may also be methyl, isobutyl, n-amyl, n-hexyl, n-heptyl, lauryl or carbethoxymethyl. R2 may also be methyl, n-propyl, n-butyl or cyclopentyl. R3 may also be methyl. The alkoxy-ethylidene compounds used as starting materials are made as in Specifications 742,206 or 756,208. Examples are given of the preparation of (1) 2-ethylthio- and 2-benzylthio-4 - (a - ethoxyethylidene) - thiazol - 5 - ones from the corresponding esters of N-(di-thiocarboxy)-glycine and ethyl ortho-acetate; and (2) 3-ethyl - 5 - (a - ethoxyethylidene) - 2 - thiothiazolid-4-one from 3-ethyl-rhodanine and ethyl ortho-acetate.