3-Nitrobenzaldehyde → HCID 20230104, compound

Participants

Reaction Steps

In 350 ml of isopropanol are dissolved 30.9 g of 1-(2-thienyl)-2-piperidinoethyl acetoacetate, 15.4 g of m-nitrobenzaldehyde and 11.7 g of methyl β-aminocrotonate, and the mixture is refluxed under heating for 20 hours. The reaction mixture is concentrated under reduced pressure and the residue is purified by column chromatography on silica gel (eluent:chloroform:methanol=10:1.2 (by volume)). The firstly eluted solution is concentrated and recrystallized from ethanol to give 2,6-dimethyl-4-(m-nitrophenyl)-1,4-dihydropyridine-3,5-dicarboxylic acid-3-methylester-5-[1-(2-thienyl)-2-piperidinoethyl]ester as crystals melting at 179° C.-181° C. This is α-diastereoisomer and the hydrochloride therefore melts at 215° C.-218° C. (decomposition). The lastly eluted solution is concentrated and recrystallized from ethanol as crystals melting at 128° C.-134° C. The hydrochloride thereof melts at 188° C.-190° C. (decomposition).

Provenance & Evidence