Acetic Acid → 9-ethyl-2-(methylamino)-9H-pyrido[2,3-b]indole-3-carboxamide

Participants

Reaction Steps

2-amino-9-ethyl-9H-pyrido[2,3-b]indole-3-carboxamide (1, 36 mg, 0.141 mmol), formaldehyde (37 wt % in water, 0.011 mL, 0.155 mmol) and acetic acid (0.0084 mL, 0.148 mmol) in methanol (2.6 mL) were stirred at room temperature for 1 h then sodium cyanoborohydride (13 mg, 0.212 mmol) was added. The reaction stirred at room temperature for 16 h, then was quenched with aqueous saturated sodium bicarbonate (2.6 mL). The resulting mixture was diluted with ethyl acetate (100 mL), washed with water (2×50 mL) and brine (50 mL), dried over magnesium sulfate, filtered and then concentrated in vacuo. The residue was adsorbed onto silica gel using methanol and purified by silica gel chromatography (5-10% methanol in methylene chloride gradient) to afford the title compound (48, 25 mg, 66%). NH4OAc standard conditions. DAD Retention time=7.84 min. M+H=269. 1H NMR (300 MHz, CDCl3): δ 8.60 (br s, 1H), 8.19 (s, 1H), 7.79 (d, J=7.9 Hz, 1H), 7.36-7.32 (m, 2H), 7.21-7.17 (m, 1H), 5.65 (br s, 2H), 4.38 (q, J=7.3 Hz, 2H), 3.12 (s, 3H), 1.42 (t, J=7.3 Hz, 3H).

Provenance & Evidence