Department of Science and Engineering for Materials, Tomakomai National College of Technology, Nishikioka 443, Tomakomai, Hokkaido 059-1275, Japan.
Carbohydr Polym. 2013 Sep 12;97(2):384-90. doi: 10.1016/j.carbpol.2013.05.031. Epub 2013 May 23.
(1)H and (13)C chemical shift assignment of the anhydroglucose units (AGUs) that comprise sodium carboxymethyl cellulose (CMC) with a degree of substitution (DS) of 0.70 was performed using 2D NMR spectra obtained from COSY, TOCSY, HSQC, and HSQC-TOCSY experiments. In the 2D COSY and TOCSY spectra, there are eight correlation networks for the H1 to H6' atoms of AGU; each (1)H resonance of the eight AGUs was assigned from the changes in the intensities of the resonances with mixing times during the TOCSY experiments. The ring (13)C resonances were assigned via analysis of HSQC-TOCSY spectra and confirmed via the HSQC spectra. Comparison of the shift data enabled the assignment of the eight AGUs as two types of both 2,3,6-tri-O- and 3,6-di-O-carboxymethylated, one type each of 2,6-di-O-, 2-mono-O-, and 6-mono-O-carboxymethylated AGU, and unsubstituted AGU. The obtained shift data will also be useful for characterization of the substitution distribution of other cellulose derivatives.
（1）H 和 （13）C 化学位移赋值的脱水葡萄糖单元（AGUs），组成的羧甲基纤维素钠（CMC）取代度（DS）为 0.70 是通过二维核磁共振谱从 COSY、TOCSY、HSQC 和 HSQC-TOCSY 实验。在二维 COSY 和 TOCSY 谱中，有八个相关网络的 H1 到 H6'原子的 AGU; 每个（1）H 共振的 8 个 AGUs 被分配从在 TOCSY 实验中随着混合时间的变化强度的共振。通过 HSQC-TOCSY 谱分析和 HSQC 谱的确认来分配环（13）C 共振。比较移位数据能够将 8 个 AGUs 分配为两种类型的 2,3,6-三-O-和 3,6-二-O-羧甲基化、2,6-二-O-、2-单-O-和 6-单-O-羧甲基化 AGU 各一种，以及未取代的 AGU。获得的位移数据也将有助于表征其他纤维素衍生物的取代分布。
