3-Nitrobenzaldehyde → HCID 136364587, compound

Participants

Reaction Conditions

Reaction Steps

To 1-phenyl-2-piperidinoethyl α-acetyl-3-nitrocinnamate prepared from 7.5 g of 3-nitrobenzaldehyde and 14.5 g of 1-phenyl-2-piperidinoethyl acetoacetate is added a solution of 4.2 g of 3-aminopyrazole in ethanol, and then stirred at 50° C. for 3 hours. The mixture is concentrated at reduced pressure, and the residue is purified by column chromatography on silica gel with chloroform-ethyl acetate-ethanol eluents to give two forms of diastereromers. The initally eluated solution is concentrated and the residue is recrystallized from ethanol to give one form (α-form) of diastereomer of 1-phenyl-2-piperidinoethyl 5-methyl-7-(3-nitrophenyl)-4,7-dihydropyrazolo[1,5-a]pyrimidine-6-carboxylate, melting at 92°-93° C. Then, the subsequently eluated solution is concentrated and the residue is recrystallized from ethanol to give the other form (β-form) of diastereomer of 1-phenyl-2-piperidinoethyl 5-methyl-7-(3-nitrophenyl)-4,7-dihydropyrazolo[1,5-a]pyrimidine-6-carboxylate, melting at 191°-192° C.

Provenance & Evidence