Malononitrile → 6-Amino-4-(4-fluorophenyl)-1,3-dimethyl-1,4-dihydropyrano[2,3-c]pyrazole-5-carbonitrile

Participants

Reaction Steps

A mixture of 4-fluorobenzaldehyde (300 μL, 2.87 mmol, 1.0 equ.), malononitrile (190 mg, 2.87 mmol, 1.0 equ.) and triethylamine (400 mL, 2.87 mmol, 1.0 equ.) in ethanol (8.0 mL) was stirred for 1 min, followed by the addition of 1,3-dimethyl-1H-pyrazol-5(4H)-one (322 mg, 2.87 mmol, 1 equ.). The reaction mixture was concentrated after 24 h and washed with ethanol and hexanes, and re-crystallized from ethanol to give 6-amino-4-(4-fluorophenyl)-1,3-dimethyl-1,4-dihydropyrano[2,3-c]pyrazole-5-carbonitrile (335 mg, 41%, 1.17 mmol) as a white solid. 1H-NMR (400 MHz) DMSO: 7.23-7.20 (m, 2H), 7.16-7.12 (m, 2H), 7.07 (s, 2H), 4.61 (s, 1H), 3.60 (s, 3H), 1.67 (s, 3H), 13C-NMR (100 MHz) DMSO: 162.7, 159.9, 144.6, 142.9, 140.7, 129.9, 120.6, 115.6, 115.4, 96.3, 59.6, 56.4, 36.7, 33.8, 12.8; LC/MS-MS: 285.1→219.1 m/z; GS1 and GS2 at 30, DP=61, CE=27, CXP=14, tR=3.80 min.

Provenance & Evidence