Studies in sulfur heterocycles. Part 15.1 Condensed heterocycles derived from thieno[2,3-c]- And thieno[3,2-c]-thiopyrans
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 7//-thieno[2,3-c]thiopyran-4(5//)-one and 4//-thieno[3,2-c]thiopyran-7(6#)-one are also reported. The Royal Society of Chemistry 1999.