4-Aminobenzoic Acid → HCID 23046218, compound

Participants

Reaction Conditions

Reaction Steps

A solution of dicyclohexylcarbodiimide (g 1.5) in tetrahydrofuran is added dropwise to a solution of 2-mercaptomethyl-3,5-dicarboethoxy-4-(m-nitrophenyl)-6-methyl-1,4-dihydropyridine (g 2.7) and p-aminobenzoic acid (g 1.0) in tetrahydrofuran (20 ml) cooled to 0° C. in nitrogen atmosphere, the mixture is stirred at 0° C. for 15 minutes and then warmed to room temperature for 18 hours. The precipitate formed is filtered and the solvent is evaporated in vacuum. The residue is dissolved in ethyl acetate (150 ml) and washed with water (3×40 ml), with a sodium bicarbonate solution (3×30 ml) and then once again with water (3×20 ml). After drying on sodium sulphate and evaporation in vacuum of the solvent, the residue is purified by chromatography on silica gel (g 100) eluting with petroleum ether/ethyl acetate (8/2). The product is recrystallized from isopropyl ether. 3,2 g of 2-(p-aminobenzoylthio)methyl-3,5-dicarboethoxy-4-(m-nitrophenyl)-6-methyl-1,4-dihydropyridine are obtained; m.p. 78°-80° C.

Provenance & Evidence