Reactions of aromatic acetylenic compounds with sulfur halides

Abstract

The reactions of phenylpropiolic acid and methyl phenylpropiolate with thionyl chloride, sulfur dichloride, sulfur monochloride and sulfuryl chloride have been investigated. Formation of benzo[b]thiophene products has been observed in some cases. The procedure is not considered to be a particularly useful route to these systems due to the relatively low yield and the mu1tiplícity of products formed in most cases. Compounds derived from the formal addition of chlorine to the triple bond are among the major products in most of these reactions. Several routes for the synthesis of pyridylpropiolíc acids and esters have been investigated. The reaction of these compounds with thionyl chloride has been studied and found to be an unattractive approach to the synthesis of the thienopyridine systems.