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:
Aug. 31, 1993
Filed:
Jul. 01, 1992
Timothy Bill, Williamsburg, VA (US);
Chris H Senanayake, North Brunswick, NJ (US);
Robert D Larsen, Bridgewater, NJ (US);
Sheo B Singh, Edison, NJ (US);
Thomas R Vernhoeven, Cranford, NJ (US);
Merck & Co., Inc., Rahway, NJ (US);
Abstract
The natural stereochemistry at the 13-position of avermectin aglycones, normally .alpha.-oriented or below the plane of the molecule, is inverted or epimerized into the .beta.-position. The procedure starts with the avermectin aglycone compounds where the 13.alpha.-hydroxy group is activated to a mesylate leaving group. The resultant 13-.alpha.-mesylate is then displaced with a cesium carboxylate and one equivalent of the respective carboxylic acid, ending with the ester group being converted to the 13-.beta.-hydroxy configuration by transesterification in high yield.
Data source: USPTO (United States Patent and Trademark Office) public patent records. Weekly synchronization. How IDiyas builds this profile