Reductive cleavage of the positional isomers of benzoylated and methylated methyl α-d-mannopyranoside
作者:Christine R. Rozanas、Gary R. Gray
DOI:10.1016/s0008-6215(96)00322-9
日期:1997.3
positional isomers and all O-benzoyl-tri-O-methyl positional isomers were converted to their respective 1.5-anhydro-D-mannitol derivatives via reductive cleavage of their anomeric carbon-oxygen bonds. For the mono-O-benzoyl positional isomers, the rate of reductive cleavage decreased in the order 2-O-benzoyl > 6-O-benzoyl > 3-O-benzoyl approximately 4-O-benzoyl. Moreover, all mono-O-benzoyl positional isomers
四个O-苯甲酰基-三-O-甲基位置异构体,六个六-O-苯甲酰基-二-O-甲基位置异构体,四个三-O-苯甲酰基-O-甲基位置异构体和四-O-合成,表征了甲基α-D-甘露吡喃糖苷的苯甲酰基衍生物,并在三乙基硅烷和三甲基甲硅烷基三氟甲磺酸盐的存在下进行了还原裂解。为了确定反应速率和如此形成的产物的身份,通过1 H NMR光谱监测反应。四-O-苯甲酰基衍生物,所有三-O-苯甲酰基-O-甲基位置异构体和2.4-二-O-苯甲酰基-3.6-二-O-甲基位置异构体对还原裂解条件完全稳定,但其他二-O-苯甲酰基-二-O-甲基位置异构体和所有O-苯甲酰基-三-O-甲基位置异构体均转化为各自的1。5-脱水-D-甘露醇衍生物通过其异头碳-氧键的还原性切割而形成。对于单-O-苯甲酰基位置异构体,还原裂解的速率以2-O-苯甲酰基> 6-O-苯甲酰基> 3-O-苯甲酰基约4-O-苯甲酰基的顺序降低。此外,所有单-O-苯