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:
Nov. 20, 2018
Filed:
Oct. 13, 2015
Zhejiang Huahai Pharmaceutical Co., Ltd., Zhejiang, CN;
Zhejiang Huahai Pharmaceutical Co., Ltd., Zhejiang, CN;
Abstract
The present invention provides a method for recycling 3-carbamoylmethyl-5-methylhexanoic acid from 3-carba carbamoylmethyl moymethyl-5-methylhexanoic acid chiral resolving mother liquor. The method comprises the following steps: (a) distilling 3-carbamoylmethyl-5-methylhexanoic acid chiral resolving mother liquor, adding aromatic hydrocarbon, heating to dissolve, keeping the temperature and stirring; (b) after completing the reaction in step (a), cooling the reaction solution to 30-60° C., then adding alkali liquor dropwise, keeping the temperature and reacting; and (c) after completing the reaction in step (b), cooling the reactant to 20-30° C., layering, adjusting the pH of the separated water layer to 1 to 2, performing extraction by using an organic solvent, distilling an organic phase under a reduced pressure, and crystallizing at 0±5° C. to obtain 3-carbamoylmethyl-5-methylhexanoic acid. The method provided in the present invention is convenient to operate, and the recycled product is high in purity (≥99.8%) and yield.