2,2',3,3'-四-O-乙酰基-4,4',6,6'-四脱氧-α,α-木糖基海藻糖

2,2',3,3'-Tetra-O-acetyl-4,4',6,6'-tetradeoxy-alpha,alpha-xylo-trehalose.

作者信息

Linden A, Lee C K

机构信息

Organisch-chemisches Institut, Universität Zürich, Switzerland.

出版信息

Acta Crystallogr C. 1994 Jul 15;50 ( Pt 7):1108-12. doi: 10.1107/s010827019400082x.

DOI:10.1107/s010827019400082x

PMID:8074812

Abstract

The low-temperature X-ray crystal structure of 2,2',3,3'-tetra-O-acetyl-4,4',6,6'-tetradeoxy-alpha,alpha-xylo-trehalose (I) (2,3-di-O-acetyl-4,6-dideoxy-alpha-D-xylo-hexopyranosyl 2,3-di-O-acetyl-4,6-dideoxy-alpha-D-xylo-hexopyranoside) is reported. The crystals were found to contain approximately 16% of 2,3-di-O-acetyl-6-chloro-4,6-dideoxy-alpha-D-xylo-hexopyranosyl 2,3-di-O-acetyl-4,6-dideoxy-alpha-D-xylo-hexopyranoside (II) as a result of incomplete hydrodechlorination of the intermediate 2,2',3,3'-tetra-O-acetyl-4,4',6,6'-tetrachloro-4,4',6,6'-tetradeoxy- alpha,alpha-trehalose. Except for the chloro substituent, the two molecules are crystallographically identical and the structure may be refined using a disordered model with one H atom being replaced by a Cl atom in 16% of the molecules. The two hexopyranosyl residues in both molecules have 4C1 conformations, with one of the residues adopting a nearly perfect chair conformation. The crystal packing places the Cl atom of (II) in a very crowded environment with a C-Cl bond length of 1.527 (7) A and a short intermolecular Cl...C contact of 2.884 (9) A.

摘要

报道了2,2',3,3'-四-O-乙酰基-4,4',6,6'-四脱氧-α,α-木糖基海藻糖（I）（2,3-二-O-乙酰基-4,6-二脱氧-α-D-木糖基己吡喃糖基 2,3-二-O-乙酰基-4,6-二脱氧-α-D-木糖基己吡喃糖苷）的低温X射线晶体结构。发现晶体中含有约16%的2,3-二-O-乙酰基-6-氯-4,6-二脱氧-α-D-木糖基己吡喃糖基 2,3-二-O-乙酰基-4,6-二脱氧-α-D-木糖基己吡喃糖苷（II），这是中间体2,2',3,3'-四-O-乙酰基-4,4',6,6'-四氯-4,4',6,6'-四脱氧-α,α-海藻糖不完全脱氯的结果。除了氯取代基外，这两个分子在晶体学上是相同的，并且可以使用无序模型进行结构精修，其中16%的分子中有一个H原子被Cl原子取代。两个分子中的两个己吡喃糖基残基均具有4C1构象，其中一个残基采用近乎完美的椅式构象。晶体堆积使（II）的Cl原子处于非常拥挤的环境中，C-Cl键长为1.527（7）Å，分子间Cl...C短接触为2.884（9）Å。