Abstract
The Reactions of ethoxycarbonyl isothiocyanate (23) with 4, 5-substituted 2-amino-thiazoles (24) afforded thiazolo [3, 2-a]-s-triazine-4-thio-2-ones (25), N-alkoxycarbonyl-N'-(2-thiazolyl)thioureas (26), alkyl-N-(2-thiazolyl)carbamates (27), ethyl-N-ethoxycarbonyl thiocarbamate (28) and thiocyanic acid (7). However, in the cases of the amines whose pKa values were smaller than that of 2-aminothiazole (24-a) or the amines which had some substituents on the 4-position of 24, the corresponding cyclic compounds (25) could not be obtained. A series of these phenomena was discussed in connection with basicities of 2-aminothiazoles (24) and the steric hindrance of the substituents on the 4-position of 24.
