Synthesis of 1,3,4-thiadiazoles from elemental sulfur via three-component cyclization under metal-free conditions

In this work, we demonstrate the synthesis of a variety of 2,5-disubstituted 1,3,4-thiadiazoles in 28-85% yields via three-component cyclization of 2-methylquinolines, arylhydrazides, and S powder under metal-free conditions. This approach stands out due to its broad substrate scope, excellent functional group tolerance, additive-free nature, base-free nature, easy operation, and simple reaction system. This work offers a simple, concise, and convenient pathway for the assembly of a variety of 1,3,4-thiadiazoles, which is complementary to previous methods.