5-Nitroindole → tert-Butyl 4-(5-nitro-1H-indol-3-yl)-5,6-dihydropyridine-1(2H)-carboxylate

Participants

Reaction Steps

A solution of 5-nitroindole (38) (2.0 g, 12.334 mmol) in dry ethanol (20 mL) was treated with pyrrolidine (3.08 mL, 37.002 mmol) followed by N-Boc-4-piperidone (4.91 g, 24.668 mmol) at room temperature and the resulting solution was refluxed for 3 days. The reaction was brought to room temperature, the solvent was evaporated and the crude product was purified by column chromatography (ethyl acetate:hexanes, 1:3) to obtain compound 85 (4.2 g, quantitative) as a solid. mp 210-212° C.; 1H NMR (DMSO-d6) δ 1.36-1.43 (m, 11H), 3.57 (t, 2H, J=5.7 Hz), 4.08 (s, 2H), 6.20 (s, 1H), 7.56 (d, 1H, J=9.0 Hz), 7.71 (s, 1H), 8.02 (dd, 1H, J=2.1, 9.0 Hz), 8.71 (d, 1H, J=2.1, Hz), 11.93 (s, 1H); ESI-MS m/z (%): 366 (M.Na+, 100), 288 (52).

Provenance & Evidence