Department of Physical Chemistry, Faculty of Pharmacy, Medical University of Warsaw, Banacha 1, 02-097 Warsaw, Poland.
Carbohydr Res. 2011 Nov 8;346(15):2491-8. doi: 10.1016/j.carres.2011.08.025. Epub 2011 Aug 31.
Comprehensive structural analyses were performed for N-o-, N-m-, and N-p-nitrophenyl-2,3,4-tri-O-acetyl-β-D-xylopyranosylamines. Single-crystal X-ray diffraction data were collected and revealed that one compound under investigation undergoes temperature-dependent polymorph transitions (crystal structures of three polymorphs were obtained). The number of molecules in the independent part of the crystal unit cells was in agreement with the number of resonances in solid-state (13)C NMR spectra. Therefore, the compounds exist as single polymorphs at room temperature, as confirmed by powder X-ray diffraction measurements. Significant differences in (13)C chemical shifts between solution and solid-state NMR for selected carbon atoms confirmed the existence of intra- and/or intermolecular interactions.
对 N-o-、N-m-和 N-p-硝基苯基-2,3,4-三-O-乙酰基-β-D-吡喃木糖胺进行了全面的结构分析。收集了单晶 X 射线衍射数据，结果表明其中一种化合物经历了温度依赖的多晶型转变（获得了三种多晶型物的晶体结构）。晶体单元中独立部分的分子数与固态（13）C NMR 谱中的共振数一致。因此，这些化合物在室温下以单一多晶型存在，这一点通过粉末 X 射线衍射测量得到了证实。对于选定的碳原子，溶液和固态 NMR 中（13）C 化学位移的显著差异证实了分子内和/或分子间相互作用的存在。
