Synthesis of 2-substituted-5-rnethylthiazolo[ 3,2-b ] -1,2,4-lriazoles and acylatcd 3-amino-2-imino-4-methyl-2-thiazolines

3-Amino-2-imino-4-mcthyl-2-thiazoline, 1, underwent ring closure with ethyl formate, cyanogen bromide and carbon disulfide, giving moderate yields of 2-substituted-5-methylthiazolo 3,2-b ]-1,2,4-triazoles, II. Reaction of I-HCl with acid anhydrides (acetic, propionie, trifluoroacetic) resulted in the formation of the corresponding II compounds, whereas other anhydrides (benzoic, perfluoropropionic, perfluorobutyric) gave high yields of 3-aeylamido-2-acylimido-4-melhyl-2-thiazolines. With acid chlorides and I-HCl, in the presence of trielhylamine, mixtures of 2-acyl-irnino-3-aniino-4-methyl-2-thiazolines and 2-aeylimino-3-(diacylamido)-4-methyl-2-thiazolines are formed. Spectral characteristics are reported.