CONFORMATION OF O-METHYLATED AMYLOSE AND CYCLODEXTRINS
CONFORMATION OF O-METHYLATED AMYLOSE AND CYCLODEXTRINS
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DOI：
10.1016/0040-4020(68)88030-5
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发表时间：
1968-01-01
期刊：
影响因子：
2.1
通讯作者：
VIGEVANI, A
中科院分区：
文献类型：
--
作者：
CASU, B;REGGIANI, M;VIGEVANI, A
通过PMR [顺磁共振]和IR光谱研究了O-甲基化直链淀粉、环糊精和模型O-甲基化葡萄糖和二葡萄糖的吡喃葡萄糖单元的构象。发现O-甲基化α-葡萄糖和[α]-1，4-连接的二-和多-葡萄糖的C1-H和C2-H键分别是平伏的和轴向的，并且与吡喃葡萄糖单元的椅子Cl构象一致。部分甲基化的化合物在非极性（四氯化碳，三氯甲烷）以及在极性（DMSO）溶剂中的氢键也进行了研究。发现2，6-二-O-甲基化-和[β]-环糊精的C-3处的OH与相邻单元的C-2处的甲氧基的氧分子内氢键结合。这种内部氢键是溶剂和浓度无关的，并解释了环糊精和可能还有直链淀粉的C-3位OH甲基化的抗性。
The conformation of the glucopyranose units of O-methylated amylose, cyclodextrins and of model O-methylated glucoses and di-glucoses was investigated by PMR [paramagnetic resonance] and IR spectroscopy. The C1-H and C2-H bonds of O-methylated a-glucoses and of [alpha]-1, 4-linked di- and poly-glucoses were found to be equatorial and axial, respectively and consistent with the chair Cl conformation of the glucopyranose units. The hydrogen bonding of partially methylated compounds in nonpolar (CCl4, CHCl3) as well as in polar (DMSO) solvents was also studied. The OH at C-3 of 2,6-di-O-methylated - and [beta]-cyclodextrin was found to be intramolecularly hydrogen-bonded to the oxygen of the methoxyl at C-2 of the adjacent unit. This internal hydrogen bond is solvent- and concentration-independent and accounts for the resistance to methylation of the OH at C-3 of cyclodextrins and probably also amylose.