Synthesis and quantum calculations of 1,3-thiazoles and 1,3,4-thiadiazole derivatives via pyridinylthioureas

摘要

In this study, the reaction of 4- and 2-aminOpyridines with phenyl isothiocyanate afforded the corresponding 1-phenyl-3-(pyridin-4-yl)thiourea 1 and its pyridin-2-yl analog 20. The reaction of 1 with ethyl chloroac-etate gave 3-phenyl-2-(pyridin-4-ylimino)thiazolidin-4-one (3B), which upon a condensation reaction with aldehydes furnished 5-benzylidene derivatives 4a-c. Compounds 1 and 20 underwent heterocyclization upon their reaction with hydrazonoyl chloride 5 and gave the corresponding 1,3,4-thiadiazoles 8 and 22; however, the treatment of 1 and 20 with hydrazonoyl chloride 10 afforded the corresponding 1,3-thiazoles 14 and 25. The quantum calculations were studied using the density functional theory of the starting materials and some products.