反应详情

To a stirred solution of 1-(4-aminophenyl)-3-(3-pyridyl)-5-ethylpyrazole (300 mg, 1.14 mmol) and o-tolualdehyde (260 mg, 2.25 mmol) in 5% HOAc/MeOH (6 mL) at room temperature under argon, sodium cyanoborohydride (200 mg, 3.18 mmol) was added. The reaction mixture was stirred at room temperature for 4 h and then concentrated, diluted with water, extracted into ethyl acetate, washed with brine. The residue obtained on concentration was chromatographed on silica gel (eluant, gradient of 25-50% EtOAc in hexane) to provide the title compound as an oil that solidified on trituration with ether/petroleum ether (97 mg, 23%), m.p. 117-9° C. NMR (CDCl3, 400 MHz): 9.1 (s, 1H); 8.5 (br, 1H); 8.1 (br, 1H); 7.4-7.2 (overlapping m, 7H), 6.7 (d,2H), 6.5 (s, 1H), 4.4 (s, 2H), 4.1 (br, 1H), 2.7 (q, 2H), 2.4 (s, 3H), 1.3 (t, 3H).

1. concentrationconcentrated
2. additiondiluted with water
3. extractionextracted into ethyl acetate
4. washwashed with brine
5. customThe residue obtained on concentration
6. customwas chromatographed on silica gel (eluant, gradient of 25-50% EtOAc in hexane)