Nicardipine

Manufacturing Process

A mixture of 4.98 g of acetoacetic acid N-benzyl-N-methylaminoethyl ester, 2.3 g of β-aminocrotonic acid methyl ester, and 3 g of m-nitrobenzaldehyde was stirred for 6 hours at 100°C in an oil bath. The reaction mixture was subjected to a silica gel column chromatography (diameter 4 cm and height 25 cm) and then eluted with a 20:1 mixture of chloroform and acetone. The effluent containing the subject product was concentrated and checked by thin layer chromatography. The powdery product thus obtained was dissolved in acetone and after adjusting the solution with an ethanol solution saturated with hydrogen chloride to pH 1-2, the solution was concentrated to provide 2 g of 2,6-dimethyl-4-(3'-nitrophenyl)1,4-dihydropyridine-3,5-dicarboxylic acid 3-methylester-5-β-(N-benzyl-N-methylamino)ethyl ester hydrochloride. The product thus obtained was then crystallized from an acetone mixture, melting point 136°C to 140°C (decomposed).

Therapeutic Function

Vasodilator

Mechanism of action

Nicardipin relaxes smooth musculature of vessels, lowers resistance of coronary and peripheral vessels, increases blood flow in vessels of the brain, causes a moderate and stable hypotensive effect, and reduces the myocardial need for oxygen.

Synthesis

Nicardipine, 1,4-dihydro-2,6-dimethyl-4-(3-nitrophenyl)-methyl-2-[(methylphenylmethyl)- amino]ethyl ester 3,5-pirididincarboxylic acid (19.3.7), is synthesized in a manner analogous to the synthesis of nifedipine, the only difference being that in the Hantsch synthesis, two different β-dicarbonyl compounds are used simultaneously with o-nitrobenzaldehyde. During this, one of these in the enamine form of acetoacetic ester is simultaneously used as an amine component. A heterocyclization reaction is accomplished by reacting, the methyl ester of β-aminocrotonic acid with the 2-methyl-2-benzylaminoethyl ester of acetoacetic acid.