By the treatment of N-3-bromo-3-alkenylthioamides with sodium hydroxide in DMF-H2O in the presence of tetra-butylammonium bromide,series of 6-alkylidene-5,6-dihydro-4H-1,3-thiazine derivatives were prepared in moderat...By the treatment of N-3-bromo-3-alkenylthioamides with sodium hydroxide in DMF-H2O in the presence of tetra-butylammonium bromide,series of 6-alkylidene-5,6-dihydro-4H-1,3-thiazine derivatives were prepared in moderate to good yields.The cyclization is supposed to proceed via both the intramolecular vinylic nucleophilic substitution and the elimination-addition mechanisms(formation of acetylenic intermediates)in a competitive manner.展开更多
文摘By the treatment of N-3-bromo-3-alkenylthioamides with sodium hydroxide in DMF-H2O in the presence of tetra-butylammonium bromide,series of 6-alkylidene-5,6-dihydro-4H-1,3-thiazine derivatives were prepared in moderate to good yields.The cyclization is supposed to proceed via both the intramolecular vinylic nucleophilic substitution and the elimination-addition mechanisms(formation of acetylenic intermediates)in a competitive manner.
