化学修饰在质谱中的应用 3.环丙烷脂肪酸的苯并噁唑衍生物的质谱特征

Chemcal Modification in Mass Spectrometry——3. 2-Substituted Benzoxazoles as Useful Derivatives for the Loealization of Cyclopropane Ring in Long-Chain Fatty Acids

环丙烷脂肪酸是种子油脂和细菌脂质的重要组成部分，人们曾用质谱来确定链上丙烷的位置，然而位置异构的环烷酸以及简单的衍生物（如甲酯）的质谱特征极不明显，因而不能用于鉴别的目的。化学修饰是用来改善谱形并增加谱中结构信息的一种重要方法，文献报道用氢解或其它反应来使环丙烷环开裂，或借助于“远端修饰”（“remote site modifica-tion”）将环丙烷酸中的羧基改变成相应的四氢吡咯酰胺或菸醇酯再进行质谱分析，以判断环丙烷基的位置，这些方法操作不便或图谱特征不强，因而需要寻找更有效的鉴定方法。

A convenient method for the localization of cyclopropane ring in long-chain fatty acids has been developed by converting the carboxylio acid to a 2-subgtituted benzoxazole. Such derivatives modified at the remote functional group show distinctive mass spectra that clearly indicate the site of cyclopropane ring in the chain of parent acids.A convenient method for the localization of cyclopropane ring in long-chain fatty acids has been developed by converting the carboxylio acid to a 2-subgtituted benzoxazole. Such derivatives modified at the remote functional group show distinctive mass spectra that clearly indicate the site of cyclopropane ring in the chain of parent acids.