The preparation of thiazole derivatives through reactions of ethyl 3-amino-3-acylhydrazinopropenoates (1) with inorganic thiocyanates and thiourea was investigated. The reaction of 1 with sodium thiocyanate, in acetic acid in the presence of bromine, afforded ethyl 3-acylamino-4-amino-2,3-dihydro-2-iminothiazole-5-carboxylates (3) selectively. On reacting the same compounds (1) with thiourea, in acetic acid and in the presence of bromine, 4-acylhydrazino-2-aminothiazole-5-carboxylates (4) were yielded. The structure of the representative compound (3c), ethyl 4-amino-3-benzoylamino-2,3-dihydro-2-iminothiazole-5-carboxylate has been solved by means of X-Ray crystallographic data analysis.
Synthesis and structural studies of 3-acylamino-4-amino-2,3-dihydro-2-iminothiazole-5-carboxylates and 4-acylhydrazino-2-aminothiazole-5-carboxylates
CONGIU, CENZO;ONNIS, VALENTINA
2004-01-01
Abstract
The preparation of thiazole derivatives through reactions of ethyl 3-amino-3-acylhydrazinopropenoates (1) with inorganic thiocyanates and thiourea was investigated. The reaction of 1 with sodium thiocyanate, in acetic acid in the presence of bromine, afforded ethyl 3-acylamino-4-amino-2,3-dihydro-2-iminothiazole-5-carboxylates (3) selectively. On reacting the same compounds (1) with thiourea, in acetic acid and in the presence of bromine, 4-acylhydrazino-2-aminothiazole-5-carboxylates (4) were yielded. The structure of the representative compound (3c), ethyl 4-amino-3-benzoylamino-2,3-dihydro-2-iminothiazole-5-carboxylate has been solved by means of X-Ray crystallographic data analysis.
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