Process to prepare, 1,4-dihydropyridine intermediates and derivatives thereof
US6858747B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Apr 8, 2004 |
| Grant date | Feb 22, 2005 |
| Priority date | — |
| Expiry date | Apr 8, 2024 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC07D211/90
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
Abstract
An improved catalyst is disclosed for a process involving the preparation of benzylidene intermediates useful in the preparation of 1,4-dihydropyridine compounds and derivatives thereof useful as medicines such as for example felodipine. This is accomplished by the condensation of an aldehyde and an acetoacetate in the presence of a novel catalyst system that includes a pyridyl carboxylic acid and a secondary amine. It has been found that through the use of the present invention the purity and yield of the desired isomer of the benzylidene intermediate can be maximized, thus avoiding the requirement of additional purification steps. The use of these intermediates can then be further reacted to form the required dihydropyridines, again having a very high purity and yield compared with the prior art.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.