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:
Mar. 28, 2000
Filed:
Jun. 29, 1999
Boehringer Ingelheim Pharmaceuticals, Inc., Ridgefield, CT (US);
Abstract
An improved process for making chiral, .alpha.-methylated, .alpha.-substituted amino acids of the formula I ##STR1## wherein Y is a hydrogen atom and R.sub.2 is the residue of a natural or unnatural amino acid, in which process an oxazolidinone of the formula II ##STR2## is formed by reacting a protected amino acid of the formula IA ##STR3## wherein Y is a protecting group, with an aldehyde of the formula RCHO, or an equivalent thereof, in the presence of a chlorinating agent and a Lewis acid. The group R.sub.2 is introduced into the oxazolidinone intermediate of formula II in a conventional manner, and subsequent hydrolysis and deprotection, both carried out in a conventional manner, yield the chiral, .alpha.-methylated, .alpha.-substituted amino acid.