反应详情

Into a 500 mL flask was weighed 11.5 g (39.6 mmol) of 2-(2-chlorophenyl)-5-trifluoromethyl-2H-pyrazole-3-carboxylic acid, 8.95 g (46.7 mmol) of EDCI, 530 mg (4.34 mmol) of DMAP, and 200 mL of CH2Cl2. Ethanol (8.6 mL) was then added to the stirred solution which was maintained at room temperature for 3 h. The reaction was then concentrated in vacuo to remove CH2Cl2. The residue was washed into a separatory funnel with ethyl acetate and 1.0 M sodium carbonate. The ethyl acetate was separated, washed with brine, dried (Na2SO4), and concentrated in vacuo. The residue was purified by silica gel flash chromatography (Jones Flashmaster, 2×70 g Silica gel, gradient elution from 100% hexanes to 40% ethyl acetate over 30 minutes). Appropriate fractions were combined and concentrated in vacuo affording 2-(2-chlorophenyl)-5-trifluoromethyl-2H-pyrazole-3-carboxylic acid ethyl ester as a viscous yellow oil, yield: 10.0 g (79.3%); 1H NMR (400 MHz, CDCl3): δ 7.32-7.46 (m, 4H), 7.19 (d, J=6 Hz, 1H), 4.16 (q, J=7 Hz, 2H), 1.13 (t, J=7 Hz, 3H); MS (ES): 319 [M+H]+.

1. customInto a 500 mL flask was weighed
2. concentrationThe reaction was then concentrated in vacuo
3. customto remove CH2Cl2
4. washThe residue was washed into a separatory funnel with ethyl acetate and 1.0 M sodium carbonate
5. customThe ethyl acetate was separated
6. washwashed with brine
7. dry with materialdried (Na2SO4)
8. concentrationconcentrated in vacuo
9. customThe residue was purified by silica gel flash chromatography (Jones Flashmaster, 2×70 g Silica gel, gradient elution from 100% hexanes to 40% ethyl acetate over 30 minutes)
10. concentrationconcentrated in vacuo