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.

GRAPHICAL ABSTRACT

Keywords:

• 3-(2-Bromoacetyl)coumarin
• one-pot synthesis
• thiadiazine-2-thiones
• thiazoline-2-thiones

ACKNOWLEDGMENTS

The authors are thankful to the director, NIT, Warangal, for providing the facilities. One of the authors (C. H. V. S. R.) is thankful to the director for awarding an institute fellowship.