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

Participants

Reaction Steps

A mixture of anisaldehyde (350 μL, 2.87 mmol, 1.0 equ.), malononitrile (190 mg, 2.87 mmol, 1.0 equ.) and triethylamine (400 μL, 2.87 mmol, 1.0 equ.) in ethanol (10 mL) was stirred for 1 min, followed by the addition of 1,3-dimethyl-1H-pyrazol-5(4H)-one (321 mg, 2.87 mmol, 1 equ.). The reaction mixture was concentrated after 24 h and the crude material was purified by column chromatography (25% ethyl acetate in hexanes to 100% ethyl acetate). The yellow solid was washed with ethanol and hexanes, and re-crystallized from ethanol to give 6-amino-4-(4-methoxyphenyl)-1,3-dimethyl-1,4-dihydropyrano[2,3-c]pyrazole-5-carbonitrile (370 mg, 1.25 mmol, 44%) as a white solid. 1H-NMR (400 MHz) CDCl3: 7.12-7.10 (d, 2H), 6.85-6.83 (d, 2H), 4.61 (s, 2H), 4.55 (s, 1H), 3.79 (s, 3H), 3.69 (s, 3H), 1.80 (s, 3H) 13C-NMR (100 MHz) CDCl3: 158.8, 157.9, 144.5, 144.4, 134.5, 128.8, 119.3, 114.0, 96.4, 64.2, 55.2, 36.7, 33.7, 12.7; LC/MS-MS: 297.0→231.2 m/z; GS1 and GS2 at 30, DP=61, CE=27, CXP=16, tR=3.71 min.

Provenance & Evidence