Studies on Organic Sulfur Compounds. XI. Synthesis of 2-Alkylthio-thiazolo [3, 2-a]-s-triazine-4-ones

1-Alkoxycarbonyl-3-(2-thiazolyl) thioureas (A) were reacted with alkyl halides in presence of potassium carbonate to afford 1 (H)-alkoxycarbony1-2-alkyl-3-(2-thiazolyl)-isothioureas (D), 1-alkoxycarbony1-2-alkyl-3-(3-alkylthiazolin-2-ylidene) isothioureas (E) 2-alkylthio-thiazolo [3, 2-a]-s-triazine-4-ones (C). However, the rate of this reaction the yields of the products were dependent on the kinds of alkyl halide and thiazolyl thioureas (A). The cyclization products (C) were obtained in a good yield by the thermal treatment of the compounds (E).