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:
Feb. 15, 2000
Filed:
Jul. 20, 1998
Andreas Brunner, Brig, CH;
Lonza, Ltd., Gampel/Valais, CH;
Abstract
Cyclobutane-1,2-dicarboxylic esters of the formula: ##STR1## in which R.sup.1 is a C.sub.1-8 -alkyl group, an optionally substituted mono- or bicyclic cycloaliphatic group having 3 to 10 ring carbon atoms, an optionally substituted aryl or arylalkyl group or an optionally substituted saturated heterocyclic group and R.sup.2 is either C.sub.1-4 -alkyl or both radicals R.sup.2 together form a group of the formula --(CH.sub.2).sub.n --(n is 2 to 4), are prepared from the corresponding maleic or fumaric esters and ketene acetals in the presence of a Lewis acid and a sterically hindered base. The reaction is stereoselective when optically active maleic or fumaric esters are employed. The cyclobutane-1,2-dicarboxylic esters (I), in particular those having trans configuration, are intermediates in the synthesis of pharmaceutically active compounds.