2-Amino-4-methylthiazole nitrate

Amino-4 -methylthiazole slowly decomposes on storage to a red viscous mass. It can be stored as the nitrate, which is readily deposited as pink crystals when dilute nitric acid is added to a cold ethanolic solution of the thiazole. The nitrate can be recrystallised from ethanol, although a faint pink colour persists. Alternatively, water can be added dropwise to a boiling suspension of the nitrate in acetone until the solution is just clear charcoal is now added and the solution, when boiled for a short time, filtered and cooled, deposits the colourless crystalline nitrate, m.p. 192-194° (immersed at 185°). The thiazole can be regenerated by decomposing the nitrate with aqueous sodium hydroxide, and extracting the free base with ether as before. 

When 2-amino-4-methylthiazole is nitrated under mild conditions, 2-nitramino-4-methylthiazole (180) is isolated (Scheme 114) (16, 194. 374). 

Ref 2), 184-5° (decomp) (Ref 3). Was prepd by nitrating 2-amino-4-methylthiazole with mixed nitric-sulfuric acids, as indicated in Ref 3... 

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