4-Substituted 2-mercaptothiazoles

Substitution of an ester of dithiocarbamic acid such as alkyl or benzyl ester (171), or their salts leads directly to 2-substituted mercaptothiazoles (172) (Scheme 87) (272, 461). Some of these compounds have an antifungal activity (561). 

Substitution of an ester of dithiocarbamic acid or its salts leads directly to 2-substituted mercaptothiazoles (Scheme 181). 

Each of the possible hydroxy- and mercaptothiazoles has been described. Seleno-2-thiazole has been used for silver halide emulsions in photographic processes (1). but little is known of its properties (2). Since the 2-substituted compounds have been studied more extensively, thev are considered first. 

A-4-Thiazoline-2-thiones can be obtained directly from 2-thiazolyldiazonium tetrafluoroborate by reaction with an excess of thiourea (9). When 1 1 stoichiometry is used, the adduct (7) can be isolated. Further treatment of 7 with an excess of thiourea leads to the 2-mercaptothiazole (3) (9). 2-Iminothiazoles (8) when heated at 150°C with CS2 give N-substituted A-4-thiazoline-2-thiones (9) (Scheme 31... 

Chemical Properties of 1,3,4-Thiadiazoles. Thermal decomposition of cis-(288) proceeds at 50°C to give ( , -Bu C=NN=CHBu, but decomposition of fra s-(288) proceeds only at 145 C, giving (jE )-Bu HC=NNHCOBu and SO, which disproportionates to S and SO2. Several reactions of substituted 2-mercaptothiazoles with chloroacetamides, chlorodiaminotriazines, and ethyl bromoacetate-hydrazine-substituted benzaldehydes, and of 2,5-... 

The tosyloxylation of suitable ketones followed by heterocyclization has been utilized in the syntheses of the following heterocyclic systems 2-aroylbenzo[fe]furans [194], 3-aryl-5,6-dihydroimidazo[2,l- ][l,3]-thiazoles [194], 6-arylimidazo[2,l- ]thiazoles [195], (15 ,2/ )-indene oxide [196], 2-mercaptothiazoles [197], triazolo-[3,4-fc]-l,3,4-thiadiazines [198], dihydroindeno[l,2-e][l,2,4]triazolo[3,4- ][l,3,4]thiadiazines [199], furo[3,2-c]coumarins [200], 4,5-diarylisoxazoles [201], 2-substituted 4,5-diphenyloxazoles [202], quinoxaline [203], 3-carbomethoxy-4-arylfuran-2-(5//)-ones [204], thiazol-2(3//)-imine-linked glycoconju-gates [205] and other important heterocycles. 

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