Thiazole 2-acetamido-5-methyl

Reduction of 2.4-dimethyl-5-nitrothiazole with activated iron gives a product that after acetylation yields 25% 2.4-dimethyl-5-acetamido-thiazole (58). The reduction of 2-methyl 5-nitrothiazole is also reported (351 to give a mixture of products. The nitro group of 2-acetylhydrazino-5-nitrothiazole is reduced by TiCl in hydrochloric acid or by Zn in acetic acid (591. 

Acetamido-4-methy)thiazole when enzymatically brominated is converted to a mixture of 2-acetamido-4-methyd 5-bromothiazole (200) and dibromacetamido-4-methyl-5-bro mo thiazole (201) (Scheme 127) (138, 436). 

An alkyl group occupying the 4-position of the thiazole ring may condense if the 5-position is substituted. 2-Acetamido-4-methyl-5-nitrothiazole (80) and p-cvanobenzaldehyde when refluxed with small amounts of piperidine yield the 4-styryl derivative (81) (Scheme 57) (238, 239). 

Sulfenamidothiazoles heated in acetic anhydride rearrange to 2-acetamido-5-thiophenoxythiazoles (337) (Scheme 193) (32, 456, 457). Only decomposition products are found when these conditions are applied to 336 with X = C1 or methyl. Substitution in the 4-position of the thiazole ring (R = methyl, phenyl), however, favors the rearrangement (see p. 82). 

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