反应详情

To a stirred solution of 1(4-aminophenyl)-3-(3-pyridyl)-5-ethylpyrazole (300 mg, 1.14 mmol) and 2-chloro-6-fluorobenzaldehyde (360 mg, 2.27 mmol) in 5% HOAc/MeOH (6 mL) at room temperature under argon was added sodium cyanoborohydride (180 mg, 2.86 mmol). The reaction mixture was stirred at room temperature for 4 h and then concentrated, diluted with water, extracted into ethyl acetate and 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 which solidified on trituration with ether/petroleum (152 mg, 32%). m.p. 123-5° C. NMR (CDCl3, 400 MHz): 9.1 (s, 1H); 8.6 (br, 1H); 8.2 (br, 1H); 7.4-7.2 (overlapping m, 5H), 7.05 (m, 1H), 6.8 (d, 2H), 6.6 (s, 1H), 4.6 (s, 2H), 4.4 (br, 1H), 2.7 (q, 2H), 1.2 (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)