Process to prepare dihydropyridine and derivatives thereof
US5977369A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 28, 1995 |
| Grant date | Nov 2, 1999 |
| Priority date | — |
| Expiry date | Dec 28, 2015 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC07D211/90
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
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.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.