A New Efficient Method for the Synthesis of Fused [1,2,5]Thiadiazoles and Their Dearomatization with C‐Nucleophiles

Abstract

General method for the annulation of [1,2,5]thiadiazole ring to pyridine and benzene cycle has been developed using sulfur monochloride as a sulfur source. On this basis a number of [1,2,5]thiadiazolo[4,3‐b]pyridines and benzo[c]thiadiazoles were synthesized. The most π‐deficient [1,2,5]thiadiazolo[4,3‐b]pyridines readily react with neutral carbon nucleophiles such as CH‐acids, indoles, pyrrole and phloroglucinol to give 1,4‐adducts.