v-Triazolines. Part 7. 3-Arylaminothiophens from hexahydrothiopyrano[3,4-d]-v-triazoles

Abstract

By treating tetrahydrothiopyran-4-one with secondary amines and aryl azides. 1-aryl-7a-amino-1,3a,4,6,7,7a-hexahydrothiopyrano[3,4-d]-v-triazoles (2) were obtained. On heating with acids, compounds (2) afforded mixtures of the corresponding 3-arylamino-2-methylthiophen (3) and 1-aryl-1,4,6,7-tetrahydrothiopyrano[3,4-d]-v-triazole (4). The triazoles (4) were also obtained on heating compounds (2) with sodium hydroxide in methanol. 3,6-Dihydro-4-morpholino-2H-thiopyran (6) was treated with 4-nitrophenylsulphonyl azide yielding 4-morpholino-3-(4-nitrophenylsulphonylamino)-3,6-dihydro-2H-thiopyran (7). Reaction mechanisms are discussed.