Chemistry of thienopyridines. VI. Reaction of hydrogen sulfide with pyridines bearing C2‐groups in the 3‐position

Abstract 3‐Substituted pyridines (bearing vinyl, ethyl, α‐hydroxyethyl, and acetyl substituents) react with hydrogen sulfide at 630° to give low yields of thieno[2,3‐b]pyridine and thieno[3,2‐c]‐pyridine. For 3‐vinylpyridine as substrate, it is proposed that a free‐radical process is involved in this synthesis.