A1H-NMR Spectroscopic Investigation of the Conformation of the Acetamido Group in Some Derivatives ofN-Acetyl-D-allosamine and -D-glucosamine
作者:Paul Fowler、Bruno Bernet、Andrea Vasella
DOI:10.1002/hlca.19960790127
日期:1996.2.7
The population of the conformations obtained by rotation around the C(2)N and the NC(O) bonds of AllNAc, GlcNAc, and GlcNMeAc derivatives was investigated by 1H-NMR spectroscopy. The AllNAc-derived α-D-and β-D-pyranosides 4–7, the AllNAc diazirine 16, and the GlcNAc-derived axial anomers α-D-8–10 prefer the (Z)-anti-conformation. A significant population of the (Z)-syn-conformer in the (Z)-syn/(Z)-anti-equilibrium
通过1 H-NMR光谱研究了通过围绕AllNAc,GlcNAc和GlcNMeAc衍生物的C(2)N和NC(O)键旋转获得的构象总数。AllNAc衍生的α-D-和β-D-吡喃糖苷4-7,AllNAc重氮基16和GlcNAc衍生的轴向异构体α-D- 8-10偏爱(Z)-反构象。(的甲显著人口Ž) -顺式的(-conformer Ž) -顺/(ż) -反对于赤道端基异构体β-D- -equilibrium 8-10和GlcNAc的二吖丙因17HC(2)的上场位移,HC(1)和HC(3)的下场位移以及NOE测量结果证明了这一点。(Z)-顺式构象的种群取决于C(1)上的取代基,并且对于六氟异丙基糖苷而言是最高的。β-D- 14的(Z)-顺式构象的种群随着溶剂极性的增加而减少,但是在D 2 O中仍观察到大量的溶液。而半缩醛22的α-D-端基异构体甲基糖苷21更喜欢D 2中的(Z)-反构象在溶液中,相应