Synthesis of enantiomers of 3-methyl- and 3-phenyl-3,4-dihydro-2H-[1,4]benzothiazines and their 1,1-dioxides via an acylative kinetic resolution protocol
作者:Dmitry A. Gruzdev、Evgeny N. Chulakov、Liliya Sh. Sadretdinova、Mikhail I. Kodess、Galina L. Levit、Victor P. Krasnov
DOI:10.1016/j.tetasy.2015.01.010
日期:2015.2
(ee >97%). This method proved to be less suitable for the preparation of the (S)-enantiomer of 3,4-dihydro-3-phenyl-2H-[1,4]benzothiazine (ee up to 93%) and its sulfone (ee 82%) which were both obtained in low yields. The loss of enantioselectivity for (S)-3,4-dihydro-3-phenyl-2H-[1,4]benzothiazine and its sulfone occurred during hydrolysis of the corresponding diastereoisomerically pure amides.
已经发现,(的酰氯小号) -萘普生,Ñ -phthaloyl-(小号) -亮氨酸,和Ñ甲苯磺酰基(小号) -脯氨酸是外消旋的3-甲基的acylative动力学拆分高效手性拆分试剂和3-苯基-3,4-二氢-3-甲基-2 ħ - [1,4]苯并噻嗪。基于该实验结果,包括acylative动力学拆分制备性协议,随后通过单个(主)非对映体酰胺和酰胺键的随后水解分离,提出了。使用与各种手性拆分剂该方法中,(小号) -和(- [R)3,4-二氢-3-甲基-2 -对映体ħ-得到[1,4]苯并噻嗪(EE> 99%)。酰胺的非对映体相应的氧化,随后导致了(脱酰小号) -和(- [R )-对映体的3,4-二氢-3-甲基-2 ħ - [1,4]苯并噻嗪1,1-二氧化钛(ee值> 97%)。这种方法被证明是不适合的(制备小号)3,4-二氢-3-苯基-2 -对映体ħ - [1,4]苯并噻嗪(EE高达93%)和它的砜(EE