Synthesis of Coumarin-Substituted 1,3,4-Thiadizine-2-thiones and 1,3-Thiazoline-2-thiones

Abstract

Interaction of phenyl hydrazine / hydrazine with carbon disulfide in the presence of KOH affords the corresponding potassium salts of dithioformates. These in situ generated salts were reacted with different 3-(2-bromoacetyl)coumarins to yield N1-phenyl-hydrazinecarbodithioic acid 2-oxo-2-(2-oxo-2H-chromen-3-yl)-ethyl ester (4a–c) and hydrazinecarbodithioic acid 2-oxo-2-(2-oxo-2H-chromen-3-yl)-ethyl ester (7a–c) respectively. Cyclocondensation of these compounds in the presence of an acid gave 3-(3-phenylamino-2-thioxo-2,3-dihydro-thiazol-4-yl)-chromen-2-ones (5a–c) and 3-(2-thioxo-3,6-dihydro-2H-[1,3,4]thiadiazin-5-yl)-chromen-2-ones (8a–c) respectively.