4-(Trifluoromethyl)benzaldehyde → tert-butyl 4-(2-(4-(trifluoromethyl)benzyl)-2,3,4,5-tetrahydro-1H-pyrido[4,3-b]indole-8-carboxamido)piperidine-1-carboxylate

Participants

Reaction Steps

To a solution of tert-butyl 4-(2,3,4,5-tetrahydro-1H-pyrido[4,3-b]indole-8-carboxamido)piperidine-1-carboxylate (11.63 g, 29.2 mmol) and 4-(trifluoromethyl)benzaldehyde (4.8 mL, 6.12 g, 35.1 mmol) in DCM (200 mL), sodium triacetoxyborohydride (12.4 g, 8.5 mmol) was added. The reaction mixture was allowed to stir at room temperature overnight and then poured into saturated sodium bicarbonate solution (300 mL). The layers were separated, and the aqueous layer was extracted with DCM (3×100 mL). The combined organic layers were washed with brine (2×50 mL), dried (MgSO4), filtered and concentrated to give an off-white solid. Trituration with ethyl ether provided tert-butyl 4-(2-(4-(trifluoromethyl)benzyl)-2,3,4,5-tetrahydro-1H-pyrido[4,3-b]indole-8-carboxamido)piperidine-1-carboxylate (9 in Scheme 1(c)) as a white solid (13.60 g, 84%). 1H NMR (DMSO-d6, 300 MHZ) 11.03 (br s, 1H), 8.01 (d, J=7.7 Hz, 1H), 7.83 (s, 1H), 7.71 (d, J=8.3 Hz, 2H), 7.62 (d, J=7.7 Hz, 2H), 7.55 (d, J=8.8 Hz, 1H), 7.26 (d, J=8.5 Hz, 1H), 4.22-3.83 (m, 5H), 3.62 (s, 2H), 2.90-2.77 (br s, 6H), 1.82-1.70 (m, 2H), 1.55-1.30 (m, 11H) ppm; MS (ES) 557 (M+H)

Provenance & Evidence