Benzaldehyde → HCID 57750059, compound

Participants

Reaction Steps

To a solution of 2-tert-butyl 8-methyl 3,4-dihydro-1H-pyrido[4,3-b]indole-2,8(5H)-dicarboxylate (0.50 g, 1.5 mmol) in DCM (5.0 mL), TFA (5.0 mL) was added. After allowing the reaction mixture to stir at room temperature for 1 h, the volatiles were evaporated, DCM and toluene (20 mL) were added and the volatiles evaporated (2×). The resulting residue was dissolved in THF/MeOH (4:1, 10 mL) and benzaldehyde (0.17 mL, 0.18 g, 1.7 mmol) and sodium triacetoxyborohydride (0.485 g, 2.3 mmol) were added. The reaction mixture was allowed to stir at room temperature overnight and 4 more equivalents of the aldehyde and reducing agent were added to cause the reaction to go to completion. The reaction mixture was 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 a foamy residue. Column chromatography (DCM→3% MeOH/DCM) provided methyl 2-benzyl-2,3,4,5-tetrahydro-1H-pyrido[4,3-b]indole-8-carboxylate (12a in Scheme 1(h)) as a white solid (0.32 g, 66%). 1H NMR (CD3OD, 300 MHz) 8.17 (d, J=1.1 Hz, 1H), 7.73 (dd, J=8.7, 1.8 Hz, 1H), 7.44-7.27 (m, 6H), 3.88 (s, 3H), 3.83 (s, 2H), 3.73 (s, 2H), 2.95-2.88 (m, 4H) ppm; MS (ES) 321 (M+H).

Provenance & Evidence