反应详情

A mixture of 4-Nitrobenzotrifluoride (25.0 g, 131 mmol) and 4-chlorophenoxyacetonitrile (24.1 g, 144 mmol) in dry DMF (200 mL) was added dropwise over 1 h to a stirred solution of potassium tert-butoxide (32.3 g, 288 mmol) in dry DMF (200 mL) at −10° C. After complete addition the resulting purple solution was maintained at −10° C. for 3 h then poured into a mixture of ice water (200 mL) and 5 N aqueous HCl (200 mL). The resulting mixture was extracted with dichloromethane (3×300 mL). The combined extracts were washed with 10% aqueous NaOH, 5 N HCl, brine, dried over sodium sulfate, and concentrated in vacuo to give the crude (2-nitro-5-trifluoromethylphenyl) acetonitrile. The crude (2-nitro-5-trifluoromethylphenyl) acetonitrile (24.6 g, 107 mmol) was dissolved in 9:1 EtOH:H2O (300 mL) and glacial acetic acid (3.0 mL). This mixture was hydrogenated over 10% Pd/C (10.0 g) at 50 psi for 16 h at room temperature. The reaction was filtered through celite and evaporated in vacuo. The residue was partitioned between saturated aqueous sodium carbonate and dichloromethane (2×200 mL) and the combined organic extract was dried over sodium sulfate, filtered, and concentrated in vacuo. The crude material was purified by silica gel column chromatography (hexanes/ethyl acetate, 20:1, 9:1, 5:1) to afford 12.9 g (65% yield) of 5-trifluoromethyl-1H-indole as a yellow solid: 1H NMR (400 MHz, CDCl3) 8.34, (1H, br s), 7.95 (1H, s), 7.45 (2H, m), 7.32 (1H, m), 6.65 (1H, m); MS m/e 184 (M−H)−. Anal calcd. for C9H6F3N.0.15 H2O: C, 57.55; H, 3.38; N, 7.46. Found: C, 57.25; H, 2.98; N, 7.29.

1. filtrationThe reaction was filtered through celite
2. customevaporated in vacuo
3. customThe residue was partitioned between saturated aqueous sodium carbonate and dichloromethane (2×200 mL)
4. extractionthe combined organic extract
5. dry with materialwas dried over sodium sulfate
6. filtrationfiltered
7. concentrationconcentrated in vacuo
8. customThe crude material was purified by silica gel column chromatography (hexanes/ethyl acetate, 20:1, 9:1, 5:1)