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. 10, 1981
Filed:
Dec. 17, 1979
John G Dingwall, Sale, GB;
Hans Greuter, Cos Cob, CT (US);
Pierre Martin, Rheinfelden, CH;
Peter Ackermann, Reinach, CH;
Laurenz Gsell, Basel, CH;
Ciba-Geigy Corporation, Ardsley, NY (US);
Abstract
There is described a new process for the preparation of optically active 2-(2',2'-dihalogenovinyl)-cyclopropane-1-carboxylic acids substituted in the 3 position, and derivatives thereof. A racemate of certain cyclobutanones is reacted with a sulfurous acid salt of an optically active base to obtain a mixture of diastereomeric 4-2-(2',2',2'-trihalogenoethyl)-cyclobutane-1-sulfonic acid salts; this mixture is then separated into the pure diastereomeric sulfonic acid salts. Either the pure diastereomeric sulfonic acid salts are converted directly to the desired optically active products, or the optically active cyclobutanones obtained from the pure diastereomeric sulfonic acids salts by decomposition is converted, in the presence of a base to the desired product. Optionally, the product, optically active 2-(2',2'-dihalogenovinyl)-cyclopropane-1-carboxylic acids can be converted to their 1',2'-dibromo derivatives. SU