Studies in sulfur heterocycles. Part 15. Condensed heterocycles derived from thieno[2,3-c]- and thieno[3,2-c]-thiopyrans
Abstract
Several tricyclic compounds obtained by annelation of five- and six-membered nitrogen heterocycles onto thieno[2,3-c]- and thieno[3,2-c]-thiopyran are reported. New expedient syntheses of 7H-thieno[2,3-c]thiopyran-4(5H)-one and 4H-thieno[3,2-c]thiopyran-7(6H)-one are also reported.