单取代恶唑。1. 通过定向烷基化合成5-取代恶唑

Monosubstituted Oxazoles. 1. Synthesis of 5-Substituted Oxazoles by Directed Alkylation.

作者信息

Shafer Cynthia M., Molinski Tadeusz F.

机构信息

Department of Chemistry, University of California, Davis, California 95616.

出版信息

J Org Chem. 1998 Feb 6;63(3):551-555. doi: 10.1021/jo971410h.

DOI:10.1021/jo971410h

PMID:11672044

Abstract

A general method is presented for synthesis of 2-(methylthio)-5-substituted oxazoles 2. Deprotonation of the readily available 2-(methylthio)oxazole (1) with n-BuLi occurs smoothly in the presence of TMEDA and regiospecifically at C5. The organometallic 1a added rapidly to aldehydes and other electrophiles to provide 5-substituted-2-(methylthio)oxazoles in very good to excellent yields. Reductive removal of the MeS group gave the desired 5-monosubstituted oxazoles 3 in good yield.

摘要

本文介绍了一种合成2-(甲硫基)-5-取代恶唑2的通用方法。在四甲基乙二胺（TMEDA）存在下，用正丁基锂（n-BuLi）对易于获得的2-(甲硫基)恶唑（1）进行去质子化反应，反应顺利进行，且区域特异性地发生在C5位。有机金属化合物1a迅速与醛和其他亲电试剂反应，以非常好至优异的产率提供5-取代-2-(甲硫基)恶唑。通过还原去除甲硫基（MeS）基团，以良好的产率得到所需的5-单取代恶唑3。