Amide derivative of amlodipine
A derivative of amlodipine having the following formula is useful as a pharmaceutical, either alone or in combination with amlodipine, in treating angina and hypertension.
1. A process which comprises:
reacting amlodipine or a salt thereof with a carbonyl-activated maleic acid compound to form a compound of formula (1) or a salt thereof:
2. The process according to claim 1 , wherein said carbonyl-activated maleic acid compound is maleic acid anhydride.
3. The process according to claim 1 , wherein said carbonyl-activated maleic acid compound is maleic acid in the presence of an acid catalyst.
4. The process according to claim 3 , wherein said acid catalyst is a Lewis acid.
5. The process according to claim 1 , wherein said reacting step is carried out in a solvent.