Hydrochloric Acid → 7-(Trifluoromethyl)-1H-indole

Temperature

-20 °C

To a stirred mixture of 7-trifluoromethyl-1H-indole-2,3-dione (116 mg) in THF (5.00 mL) was added boron trifluoride etherate (0.205 mL, 1.62 mmol) followed by sodium borohydride (71.4 mg, 1.88 mmol). The resulting mixture was stirred at −20° C. for 2 hrs, then water (1 mL) was added and the mixture was stirred at 0° C. for 10 min. The solution was acidified to pH=1 with 2N HCl, warmed to r.t. and stirred at r.t. for 20 min prior to extraction with EtOAc. The extracts were dried over magnesium sulphate, concentrated in vacuo and the residue purified by chromatography over silica gel eluting with hexane to give 7-trifluoromethyl-1H-indole. 1H NMR (400 MHz, CDCl3) δ ppm 6.63-6.68 (1 H, m), 7.20 (1 H, t, J=7.71 Hz), 7.30-7.35 (1 H, m), 7.47 (1 H, d, J=7.33 Hz), 7.83 (1 H, d, J=8.08 Hz), and 8.56 (1 H, br. s.).

1. stirringthe mixture was stirred at 0° C. for 10 min
2. temperaturewarmed to r.t.
3. stirringstirred at r.t. for 20 min
4. extractionto extraction with EtOAc
5. dry with materialThe extracts were dried over magnesium sulphate
6. concentrationconcentrated in vacuo
7. customthe residue purified by chromatography over silica gel eluting with hexane

ORD record

ord-c5425bd5da1547e38d41239cd0d4c3c8

Source dataset

uspto-grants-2013_11

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08586546B2