3-Nitrobenzaldehyde → Nicardipine Impurity 19

Participants

Reaction Steps

9.7 g of 2-nitratoethyl acetoacetate, 7.7 g of 2-cyanoethyl 3-aminocrotonate and 7.6 g of 3-nitrobenzaldehyde in 76 ml of ethanol were heated at reflux for 7 hours. The mixture was treated in a manner similar to that of Referential Example 1, and the crystals thus obtained were applied to a silica gel column chromatography [eluent: a mixture of hexane and acetone (5:3)] and recrystallized from isopropyl alcohol to give 14.5 g of 2,6-dimethyl-4-(3-nitrophenyl)-1,4-dihydropyridine-3,5-dicarboxylic acid 3-(2-cyanoethyl) ester 5-(2-nitratoethyl) ester.

Provenance & Evidence