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:
Jan. 25, 1977
Filed:
Aug. 06, 1975
William S Knowles, St. Louis, MO (US);
Milton J Sabacky, Ballwin, MO (US);
Billy D Vineyard, Creve Coeur, MO (US);
Monsanto Company, St. Louis, MO (US);
Abstract
A process for the preparation of 3-(3,4-dihydroxyphenyl)-L-alanine (L-DOPA) wherein .alpha.-acetamido-4-hydroxy-3-alkoxy-cinnamic acid acetate is subjected to catalytic asymmetric hydrogenation to yield an optically active mixture N-acetyl-3-(4-hydroxy-3-alkoxyphenyl)-alanine acetate, with the L enantiomorph being present in a major amount and the D enantiomorph being present in a minor amount, from which N-acetyl-3-(4-hydroxy-3-alkoxyphenyl)-L-alanine acetate can be easily recovered and is then converted to L-DOPA. Novel precursors for L-DOPA are prepared in the process of this invention.