O -Benzoyl side-chain conformations in 2,3,4,6-tetra- O -benzoyl-β- D -galactopyranosyl-(1→4)-1,2,6-tri- O -benzoyl-β- D -glucopyranose (ethyl acetate solvate) and 1,2,4,6-tetra- O -benzoyl-β- D -glucopyranose (acetone solvate)
O -Benzoyl side-chain conformations in 2,3,4,6-tetra- O -benzoyl-β- D -galactopyranosyl-(1→4)-1,2,6-tri- O -benzoyl-β- D -glucopyranose (ethyl acetate solvate) and 1,2,4,6-tetra- O -benzoyl-β- D -glucopyranose (acetone solvate)
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2,3,4,6-四- O -苯甲酰基-β- D -吡喃半乳糖基-(1â4)-1,2,6-三- O -苯甲酰基-β- D 中的 O -苯甲酰基侧链构象
DOI：
10.1107/s2053229619000822
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发表时间：
2019
期刊：
影响因子：
--
通讯作者：
Serianni, Anthony S.
中科院分区：
文献类型：
--
作者：
Turney, Toby;Pan, Qingfeng;Zhang, Wenhui;Oliver, Allen G.;Serianni, Anthony S.
测定了2，3，4，6-tetra-O-benzoyl-β-d-galactopyranosyl-(1→4)-1，2，6-tri-O-benzoyl-β-d-glucopyranose乙酸乙酯半离解酸C61H50O18·0.5C4H8O2和1，2，4，6-四-O-苯甲酰基-β-d-吡喃葡萄糖丙酮单醇酸C34H28O10·C3H6O的晶体结构，并与甲基β-乳糖苷和β-d-葡萄糖苷半水合物C7H14O6·0.5H2O的晶体结构进行了比较，以评价O-苯甲酰化对键长的影响。结合角和扭转角。总体而言，O-苯甲酰化对外环和内环C-C和内环C-O键长度影响不大，但参与O-苯甲酰化反应的外环C-O键的长度随取代位的不同而延长0.02~0.04 ä 。O-苯甲酰基侧链的构象是高度保守的，羰基O原子要么遮盖了2°醇C原子上的H原子，要么平分了1°醇C原子的H-C-H键角。在决定侧链几何构型的三个键中，涉及醇类C原子的C-O键表现出比涉及羰基C原子的其余C-O键和C-C键更大的旋转可变性。这些发现与最近对糖中O-乙酰侧链构象的溶液核磁共振研究是一致的。
The crystal structures of 2,3,4,6-tetra-O-benzoyl-β-d-galactopyranosyl-(1→4)-1,2,6-tri-O-benzoyl-β-d-glucopyranose ethyl acetate hemisolvate, C61H50O18·0.5C4H8O2, and 1,2,4,6-tetra-O-benzoyl-β-d-glucopyranose acetone monosolvate, C34H28O10·C3H6O, were determined and compared to those of methyl β-d-galactopyranosyl-(1→4)-β-d-glucopyranoside (methyl β-lactoside) and methyl β-d-glucopyranoside hemihydrate, C7H14O6·0.5H2O, to evaluate the effects of O-benzoylation on bond lengths, bond angles and torsion angles. In general, O-benzoylation exerts little effect on exo- and endocyclic C—C and endocyclic C—O bond lengths, but exocyclic C—O bonds involved in O-benzoylation are lengthened by 0.02–0.04 Å depending on the site of substitution. The conformation of the O-benzoyl side-chains is highly conserved, with the carbonyl O atom either eclipsing the H atom attached to a 2°-alcoholic C atom or bisecting the H—C—H bond angle of an 1°-alcoholic C atom. Of the three bonds that determine the side-chain geometry, the C—O bond involving the alcoholic C atom exhibits greater rotational variability than the remaining C—O and C—C bonds involving the carbonyl C atom. These findings are in good agreement with recent solution NMR studies of the O-acetyl side-chain conformation in saccharides.