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. 02, 1999
Filed:
Dec. 28, 1995
Ranjit Desai, Kendall Park, NJ (US);
Daniel Alfonso Aguilar, Corpus Christi, TX (US);
Mohammad Aslam, Corpus Christi, TX (US);
Nicholas Gallegos, Corpus Christi, TX (US);
Napp Technologies, Inc., Saddle Brook, NJ (US);
Abstract
A novel process is disclosed for the preparation of dihydropyridine compounds and derivatives thereof, and more particularly felodipine. The process to prepare felodipine involves a two step procedure condensing 2,3-dichlorobenzaldehyde with methyl acetoacetate in the presence of a catalyst system. The resultant benzylidine intermediate is sequentially reacted with ethyl aminocrotonate to provide felodipine. The novelty of the present invention resides in part on (1) a new catalyst system not previously disclosed for the preparation of felodipine, (2) the absence of acid(s), (3) the control of reaction conditions to yield lower amounts of unreacted aldehyde compared to known reactions, (4) a simplified purification process, and (5) formation of negligible quantities of symmetrical diester byproducts.