Ammonium formate → Ethyl 2-(2-hydroxy-6,7,8,9-tetrahydropyrido[1,2-a]indol-9-yl)acetate

Participants

Reaction Steps

Ethyl 2-(2-(benzyloxy)-7,8-dihydropyrido[1,2-a]indol-9(6H)-ylidene)acetate (608 mg, 1.682 mmol) was dissolved in THF/MeOH (1:1) (4 mL). Ammonium formate (648 mg, 10.28 mmol) and palladium hydroxide (20 wt % Pd on carbon) (60 mg) was added under nitrogen protection. The reaction was heated at reflux for 5 h. The solid was filtered. The filtrate was concentrated, dissolved in ethyl acetate, washed with water, dried over anhydrous Na2SO4, and concentrated. The residue was purified by silica gel column chromatography to give the title compound (402 mg) as colorless oil. LCMS m/z=274.3 [M+H]+; 1H NMR (400 MHz, CDCl3) δ ppm 1.32 (t, J=7.1 Hz, 3H), 1.50-1.61 (m, 1H), 1.98-2.08 (m, 1H), 2.08-2.22 (m, 2H), 2.55 (dd, J=15.6 and 8.7 Hz, 1H), 2.94 (dd, J=15.6, 5.5 Hz, 1H), 3.44-3.52 (m, 1H), 3.80-3.88 (m, 1H), 4.07-4.13 (m, 1H), 4.24 (q, J=7.1 Hz, 2H), 4.95 (s, 1H), 6.12 (s, 1H), 6.74 (dd, J=8.6, 2.4 Hz, 1H), 6.95 (d, J=2.4 Hz, 1H), 7.10 (d, J=8.6 Hz, 1H).

Provenance & Evidence