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:
Dec. 03, 1991
Filed:
Mar. 07, 1990
Jag M Khanna, New Delhi, IN;
Naresh Kumar, New Delhi, IN;
Kiran Bala, New Delhi, IN;
Yatendra Kumar, New Delhi, IN;
Ranbaxy Laboratories Limited, New Delhi, IN;
Abstract
An improved method for preparing 2-chlorosulfinyl azetidine-4-one comprises heating a penicillin sulfoxide ester with an N-chlorohalogenating agent at a temperature of about 75.degree. C. to about 140.degree. in an inert organic solvent, and in the presence of an organic solvent insoluble, strongly basic ion exchange resin. Desirably, the ion exchange resin comprises a styrene-divinyl benzane copolymer which is about 2 to 16% cross-linked and incorporates a quaternary ammonium functionality. Such ion exchange resins are commercially available. The 2-chlorosulfinyl azetidine-4-one which is produced by this method can be cyclized in the presence of a Friedel-Crafts catalysts to afford the 3-exomethylene cepham sulfoxide ester in yields of 80-90%.