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:
Jun. 26, 1990
Filed:
Jan. 17, 1989
John Kloss, Holland, PA (US);
David Kronenthal, Yardley, PA (US);
Christopher M Cimarusti, Somerset, NJ (US);
Richard H Mueller, Ringoes, NJ (US);
E. R. Squibb & Sons, Inc., Princeton, NJ (US);
Abstract
A process is provided for preparing (trans)-4-phenyl-DL-proline derivatives, which are useful in preparing certain angiotensin converting enzyme inhibitors, which process involves reacting an ester of the structure ##STR1## wherein X is a leaving group such as tosylate, R.sup.3 is lower alkyl, R is cyclohexyl, phenyl or substituted phenyl, and R.sup.1a is a protecting group, with a potassium amide base such as potassium hexamethyldisilazide under reduced temperatures to form the trans-4-substituted proline ester derivative of the structure ##STR2## then hydrolyzing the proline ester to the acid of the structure ##STR3## and removing the R.sup.1a nitrogen protecting group to form the unprotected acid of the structure ##STR4##