Nitrogen → N-(piperidin-1-yl)-1-(4-chlorophenyl)-5-phenyl-4,5-dihydro-(1H)-pyrazole-3-carboxamide

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Reaction Steps

Part D: To a stirred suspension of 1-(4-chlorophenyl)-5-phenyl-4,5-dihydro-(1H)-pyrazole-3-carboxylic acid (1.50 gram, 5 mmol) in anhydrous acetonitrile (40 ml) is successively added N-diisopropylethylamine (DIPEA) (1.92 ml, 11 mmol), O-benzotriazol-1-yl-N,N, N′,N′-tetramethyluronium hexafluorophosphate (HBTU) (2.08 g, 5.5 mmol) and 1-aminopiperidine (0.59 ml, 5.5 mmol) and the resulting mixture is reacted at room temperature for 16 hours in a N2 atmosphere. The mixture is concentrated and added to a mixture of ethyl acetate and aqueous NaHCO3. The Ethyl acetate layer is collected, dried over MgSO4, filtered and concentrated in vacuo. The resulting residue is recrystallised from acetonitrile to give N-(piperidin-1-yl)-1-(4-chlorophenyl)-5-phenyl-4,5-dihydro-(1H)-pyrazole-3-carboxamide (compound 1), 1.34 gram, 70% yield). Melting point: 189-192° C.

Provenance & Evidence