Methyl (3S)-3,4-Dihydro-3-iodomethyl-1,4–2H-thiazine-6-carboxylate (6) undergoes racemisation when heated under reflux in ethyl methyl ketone; deuterium-labelling experiments reveal that a 1,3-sulphur migration is involved. Under corresponding conditions, methyl (3R)-3.4-dihydro-3-iodomethyl-2,2-dimethyl-1,4–2H-thiazine-6-carboxylate (20) rearranges to methyl (3R)-3,4-dihydro-3-isopropenyl-1,4–2H-
(3 S)-3,4-二氢-3-
碘甲基-1,4–2 H-
噻嗪-6-
羧酸盐(6)在乙基甲基酮中加热回流时会发生外消旋作用;
氘标记实验表明,涉及1,3-
硫的迁移。在相应的条件下,(3 R)-3.4-二氢-3-
碘甲基-2,2-二甲基-1,4–2 H-
噻嗪-6-
羧酸盐(20)重排为甲基(3 R)-3,4 -二氢-3-异
丙烯基-1,4–2 H-
噻嗪-6-
羧酸盐(8)。当在沸腾的
甲苯中加热时,(6S)-5,5-二甲基-4-
硫杂-1-
氮杂双环[4,1,0]庚-2-烯-3-
羧酸甲酯(21)也提供化合物(8)。