反应详情

A mixture of benzaldehyde (290 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 (322 mg, 2.87 mmol, 1 equiv.). The reaction mixture was concentrated after 19 h and washed with ethanol and hexanes. The crude material was purified by column chromatography on SiO2 (25% ethyl acetate in n-hexanes to 100% ethyl acetate) and then re-crystallized from ethanol to give 6-amino-1,3-dimethyl-4-phenyl-1,4-dihydropyrano[2,3-c]pyrazole-5-carbonitril (263 mg, 0.988 mmol, 34%) as a yellow powder. 1H-NMR (400 MHz) DMSO: 7.34-7.32 (m, 2H), 7.25-7.23 (t, 1H), 7.19-7.17 (d, 2H), 7.05 (s, 2H), 4.57 (s, 1H), 3.60 (s, 3H), 1.66 (s, 3H), 13C-NMR (100 MHz) DMSO: 159.9, 144.6, 144.4, 142.9, 128.8, 128.0, 127.3, 120.6, 96.5, 58.7, 37.5, 33.8, 12.8; LC/MS-MS: 267.0→201.3 m/z; GS1 and GS2 at 30, DP=61, CE=29, CXP=12, tR=3.74 min.

1. concentrationThe reaction mixture was concentrated after 19 h
2. washwashed with ethanol and hexanes
3. customThe crude material was purified by column chromatography on SiO2 (25% ethyl acetate in n-hexanes to 100% ethyl acetate)
4. customre-crystallized from ethanol