反应详情

温度

63 °C

A mixture of 1-{[4-(methyloxy)phenyl]methyl}-1H-pyrazol-5-amine (3 g, 14.76 mmol), ethyl 4-cyclopropyl-2,4-dioxobutanoate (2.72 g, 14.76 mmol) and benzene (50 mL) were heated at 63° C. for 16 h. The solvent was removed under reduced pressure. The crude residue was purified via silica gel chromatography (eluent: 0 to 25% EtOAc:Hex) to afford 2.56 g of the desired cyclized product and 1.71 g of the uncyclized adduct. The uncyclized adduct was dissolved in 25 mL of AcOH and heated to reflux for 16 hours. The solvent was removed under reduced pressure and the residue purified via silica gel chromatography (eluent: 0 to 25% EtOAc:Hex) to afford an additional 1.15 g of the desired cyclized product (combined yield=71%). LCMS E-S (M+H)=352.3. 1H NMR (400 MHz, DMSO-d6) δ ppm 1.07-1.13 (m, 4 H) 1.38 (t, J=7.07 Hz, 3 H) 2.39 (s, 1 H) 3.67 (s, 3 H) 4.41 (q, J=7.07 Hz, 2 H) 5.51 (s, 2 H) 6.84 (d, J=8.84 Hz, 2 H) 7.21 (d, J=8.59 Hz, 2 H) 7.64 (s, 1 H) 8.23 (s, 1 H).

1. customThe solvent was removed under reduced pressure
2. customThe crude residue was purified via silica gel chromatography (eluent: 0 to 25% EtOAc:Hex)
3. customto afford 2.56 g of the
4. temperatureheated
5. temperatureto reflux for 16 hours
6. customThe solvent was removed under reduced pressure
7. customthe residue purified via silica gel chromatography (eluent: 0 to 25% EtOAc:Hex)
8. customto afford an additional 1.15 g of the desired cyclized product (combined yield=71%)