THE SYNTHESIS OF 5H-THIAZOLO[2,3-C][1,2,4]TRIAZINE DERIVATIVES AND SUBSTITUTED 3-(2-ACYLVINYLTHIO)-1,2,4-TRIAZIN-5-ONES FROM 6-METHYL-3-THIOXO-1,2,4-TRIAZIN-5-ONE, 1-ACYL-2-BROMOACETYLENES, AND ALPHA-ACETYLENIC KETONES - X-RAY STUDY OF YL-6-METHYL-5H-THIAZOLO[2,3-C][1,2,4]TRIAZIN-5-ONE

3-Acyl-6-methyl-5H-thiazolo[2,3-c][1,2,4]triazines were synthesized by reaction of 1-acyl-2-bromoacetylenes with 6-methyl-3-thioxo-1,2,4-tri azin-5-one in methanol in the presence of triethylamine at 20 degrees C. The structure of benzoyl-6-methyl-5H-thiazolo[2,3-c][1,2,4]triazine was established by X-ray structural analysis. Substituted 3-(2-acetyl vinylthio)-1,2,4-triazin-5-ones were obtained by the reaction of alpha -acetylenic ketones with 6-methyl-3-thioxo-1,2,4-triazin-5-one under t he same conditions. The structures of the new compounds were confirmed by IR, H-1, and C-13 NMR spectroscopy.