Interconversions, reactivities, and structures of isomeric hydrothiochromenes
Abstract2,4-Diphenyl-5,6,7,9-tetrahydrothiochromene was isomerized to 2,4-diphenyl-5,6-tetramethylene-4H-thiopyran in the presence of HCl and DCl. The relative thermodynamic stabilities of 2,4-diphenyl-5,6-tetramethylene-6H-thiopyran and the compound thus obtained were studied. The reactivities of the isomers of all three compounds in oxidation, disproportionation, and alkylation reactions are discussed. The structures of 2,4-diphenyl-5,6,7,9-tetrahydrothiochromene and 2,4-diphenyl-5,6-tetramethylene-4H-thiopyran were established by x-ray diffraction analysis.