Products of the nitration of 2-thiazolylureas and 2-thiazolylthioureas.

Abstract

Products of the nitration of 2-thiazolylurea and 2-thiazolylthiourea derivatives with fuming nitric acid in concentrated sulfuric acid are described. The urea derivatives studied were 3-(4-methyl-2-thiazoly) urea and -thiourea (7), and their l-methyl (1 and 2, respectively) and 1, 1-dimethyl analogs. The products were the compounds nitrated at the 5-position of the thiazole moiety. With an excess of nitric acid, 1-methyl-3-(4-methyl-5-nitro-2-thiazolyl)-1-nitrourea was obtained from 1, while the corresponding 1-nitrosourea was formed from 2. A pale yellow compound was obtained from the nitration of 7. Unlike other nitrated thioureas, it did not form a colored Cu (II) chelate and was stable to acid, alkali, and heat. It was concluded to be 6-methyl-2-nitroiminothiazolo [3, 2-b] [1, 2, 4] thiadiazole from studies of its physicochemical properties, chemical reactions, and the results of X-ray crystallography. Corresponding compounds were obtained from other N-(4-alkyl-2-thiazolyl) thioureas.