3-Nitrobenzaldehyde → HCID 13589488, compound

Participants

Reaction Conditions

Reaction Steps

To the crude 1-phenyl-2-piperidinoethyl α-acetyl-3-nitrocinnamate, which was synthesized by reacting 30 g of 3-nitrobenzaldehyde with 67 g of 1-phenyl-2-piperidinoethyl acetoacetate, is added 500 ml of ethanol solution of 2-aminoimidazole prepared from 26.4 g of 2-aminoimidazole sulfate and sodium hydroxide, and then stirred at 50° C. for 5 hours. After cooling, the precipitated crystals are collected by filtration and recrystallized from ethanol to give 9.7 g of 1-phenyl-2-piperidinoethyl 7-methyl-5-(3-nitrophenyl)-5,8-dihydroimidazo[1,2-a]pyrimidine-6-carboxylate, melting at 205°-206° C. as one diastereomer (α-form). Then, the filtrate is concentrated under reduced pressure, and the residue is purified by column chromatography on silica gel with chloroform-ethyl acetate-ethanol eluents. The crystals thus obtained are recrystallized from a mixture of chloroform and ethanol to give 4.8 g of 1-phenyl-2-piperidinoethyl 7-methyl-5-(3-nitrophenyl)-5,8-dihydroimidazo[1,2-a]pyrimidine-6-carboxylate, melting at 216° -217° C. with decomposition as the other diastereomer (β-form).

Provenance & Evidence