Trifluoroacetic acid → N-(4-Nitro-3-(trifluoromethyl)phenyl)piperidin-4-amine

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Reaction Steps

To a solution of tert-butyl 4-[[4-nitro-3-(trifluoromethyl)phenyl]amino]piperidine-1-carboxylate (1 g, 2.6 mmol) in dichloromethane (10 mL) was added trifluoroacetic acid (3 ml). The solution was stirred for 2 hours at room temperature and then concentrated under vacuum. The crude material was diluted with water (50 ml), adjusted pH to 9 with sodium bicarbonate (saturated aqueous), and extracted with dichloromethane (3×100 ml). The organic layers were combined and dried over anhydrous sodium sulfate, filtered, and concentrated under vacuum to afford N-[4-nitro-3-(trifluoromethyl)phenyl]piperidin-4-amine as a yellow powder (800 mg, crude); (ES, m/z): [M+H]+ 290.1; 1H NMR (300 MHz, DMSO-d6): δ 8.08 (d, J=9.0 Hz, 1H), 7.20-7.80 (br s), 7.60 (d, J=7.8 Hz, 1H), 7.11 (d, J=2.4 Hz, 1H), 6.91 (dd, J=2.4, 9.0 Hz, 1H), 3.70 (m, 1H), 3.22 (d, J=12.6 Hz, 2H), 2.91 (dd, J=10.5, 11.4 Hz, 2H), 1.99 (d, J=11.4 Hz, 2H), 1.52 (m, 2H).

Provenance & Evidence