Benzaldehyde → 6-Amino-3-methyl-1,4-diphenyl-1,4-dihydropyrano(2,3-c)pyrazole-5-carbonitrile

Participants

Reaction Steps

To a stirred solution of benzaldehyde (290 μL, 2.87 mmol), malononitrile (190 mg, 2.87 mmol) and 3-methyl-1-phenyl-1H-pyrazol-5(4H)-one (500 mg, 2.87 mmol) in anhydrous DCM (60 mL) was added anhydrous Na2SO4 (407 mg, 2.87 mmol) and ethylhydrocupreine hydrochloride (46 mg, 0.122 mmol). The reaction mixture was stirred at room temperature (25 h). After filtration and washing with DCM, the solvent was removed under reduced pressure. The crude mixture was subjected to flash column chromatography over silica gel (hexanes:ethyl acetate; 1:1) to give 6-amino-3-methyl-1,4-diphenyl-1,4-dihydropyrano[2,3-c]pyrazole-5-carbonitrile (270 mg, 0.822 mmol, 29%) as white solid. 1H-NMR (400 MHz) CDCl3: 7.69-7.66 (d, 2H), 7.50-7.46 (t, 2H), 7.39-7.26 (m, 6H), 4.68 (s, 1H), 4.67 (s, 2H), 1.91 (s, 3H), 13C-NMR (100 MHz) CDCl3: 158.1, 146.4, 143.8, 141.9, 137.5, 129.2, 128.8, 127.8, 127.5, 126.7, 121.2, 119.0, 98.3, 64.0, 37.4, 12.8; LC/MS-MS: 329.1→263.1 m/z; GS1 and GS2 at 30, DP=56, CE=31, CXP=18, tR=4.18 min.

Provenance & Evidence