Oxidation of the dihydrothiazine lactone (17) and the ester (2) with m-chloroperbenzoic acid yields the respective (R)-oxides (18) and (10); the analogous (S)-oxides (33) and (30) are obtained from the dimethyl derivatives (31) and (28). The foregoing sulphoxides undergo thermally induced racemisation under mild conditions; deuterium-incorporation experiments implicate the sulphenic acids, e.g.(23)
所述dihydrothiazine内酯(17)与酯(2)与氧化米
氯过
苯甲酸得到相应的(- [R)-oxides(18)和(10); 从二甲基衍
生物(31)和(28)获得类似的(S)-氧化物(33)和(30)。前述亚砜在温和的条件下经历热诱导的外消旋作用。
氘掺入实验暗示了
亚硫酸,例如(23),作为反应中间体。