A Three-Component Approach to 3,5-Diaryl-1,2,4-thiadiazoles under Transition-Metal-Free Conditions

A novel route is disclosed for the synthesis of 1,2,4-thiadiazoles starting from amidines, elemental sulfur, and 2-methylquinolines or aldehydes under transition-metal-free conditions. This three-component approach affords efficient and rapid access to 3,5-diaryl substituted 1,2,4-thiadiazoles with good tolerance of a broad range of funcitional groups. Mechanistic studies reveal a radical-involved pathway.