Reaction Steps
To a solution of 1-tert-butoxycarbonyl-5-[1-(2-chlorophenyl)-6-methylheptyl]-1H-pyrrolo[3,2-c]pyridin-5-ium bromide (2.4 g, 4.0 mmol) in 70% EtOH (60 mL) was added (at room temperature, with vigorous stirring, and in portions) sodium borohydride (0.30 g, 8.0 mmol). When the sodium borohydride was completely added, the stirring was terminated and mixture was stirred for 0.5 hours. The solvent was evaporated under reduced pressure and water (60 mL) was added. The product was extracted with dichloromethane (3×150 mL) and the combined organic extracts were dried over sodium sulfate, filtered, and concentrated under reduced pressure. The crude residue was purified by column chromatography (silica gel, ethyl acetate/heptane=1/10 to 1/3) to yield 5-[1-(2-chlorophenyl)-6-ethoxycarbonyl-6-methylheptyl]-4,5,6,7-tetrahydro-pyrrolo[3,2-c]pyridine-1-carboxylic acid tert-butyl ester (1.45 g, 60.9% yield) as a yellow oil. 1H NMR (Field: 300 MHz, Solvent: CD3OD/TMS) δ (ppm): 7.50 (dd, 1H, J=7.5, 1.2 Hz), 7.37 (d, 1H, J=8.1, 1.5 Hz), 7.27-7.10 (m, 3H), 5.94 (d, 1H, J=3.3 Hz), 4.16-4.13 (m, 1H), 4.09 (q, 2H, J=6.9 Hz), 3.62 (d, 1H, J=14.1 Hz), 3.28 (d, 1H, J=13.5 Hz), 2.85-2.60 (m, 4H), 1.98-1.76 (m, 2H), 1.55 (s, 9H), 1.42 (t, 2H, J=6.9 Hz), 1.28-1.16 (m, 4H), 1.21 (t, 3H, J=7.2 Hz), 1.11 (s, 6H). 13C NMR (Field: 75 MHz, Solvent: CDCl3/TMS) δ (ppm): 177.98, 149.49, 139.66, 134.90, 129.44, 129.15, 127.93, 127.60, 126.84, 120.92, 119.77, 109.20, 83.26, 63.76, 60.33, 48.81, 48.19, 42.30, 40.80, 33.23, 32.13, 28.31, 26.07, 25.35, 22.96, 14.52. HRMS (DART-TOF): Calculated for C20H41ClN2O2 (M+H)+: 517.2828. found 517.2833.
