The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Mar. 03, 2020
Filed:
Jun. 21, 2017
Zhejiang Huahai Pharmaceutical Co., Ltd, Taizhou, CN;
Zhejiang Huahai Zhicheng Pharmaceutical Co., Ltd, Linhai, CN;
Pan Guo, Linhai, CN;
Musong Liu, Linhai, CN;
Zengle Zhou, Linhai, CN;
Wenling Zhang, Linhai, CN;
Peng Wang, Linhai, CN;
ZHEJIANG HUAHAI PHARMACEUTICALS CO., LTD, Taizhou, CN;
ZHEJIANG HUAHAI ZHICHENG PHARMACEUTICAL CO., LTD, Linhai, CN;
Abstract
Provided is a method for preparing a pregabalin intermediate 3-isobutylglutaric acid monoamide. The method comprises: 1) adding 3-isobutylglutaric acid and urea into a first organic solvent; 2) keeping warm and refluxing when heated to 100-140° C.; 3) adding water when cooled to 70-90° C.; 4) adding an ion membrane alkaline when cooled to 40-60° C., adjusting the pH to 11.0-14.0, then keeping warm at 40-60° C.; 5) when finished keeping warm, removing an organic layer; 6) adding an acid into the water layer to adjust the pH to 1.0-3.0; 7) extracting the solution acquired in step 6) by using a second organic solvent of a total volume of V, vacuum distilling 0.5-0.6 V of the organic solvent from an organic layer acquired by extraction; and 8) cooling to 0-15° C. and crystallizing to acquire 3-isobutylglutaric acid monoamide.