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:
Jan. 08, 2019
Filed:
Mar. 25, 2016
Zhejiang Huahai Pharmaceutical Co., Ltd, Linhai, CN;
ZHEJIANG HUAHAI PHARMACEUTICAL CO., LTD., Zhejiang, CN;
Abstract
The present invention provides a method for preparing a pregabalin intermediate 3-carbamoymethyl-5-methylhexanoic acid without solvent. The method comprises the following steps: a) cooling an ammonia water system to a certain temperature; b) adding 3-isobutylglutaric anhydride dropwise to the system, then keeping temperature, and reacting; c) after completing the reaction, adding an acid to the system to adjust pH; d) after adjusting pH, cooling, then keeping temperature, crystallizing, then suction filtering and drying; and e) adding a solvent to the dried substance, slurrying, and suction filtering and drying to obtain the final product. The method provided in the present invention for preparing 3-carbamoymethyl-5-methylhexanoic acid is high-yield, green, environmentally-friendly, simple and convenient, and of less pollution.