Step a): To a stirred solution of Intermediate 1 (50 mg, 0.17 mmol) and DIEA (73 μl, 0.42 mmol) in acetonitrile (1 ml) is added (2-bromo-ethyl)-benzene (26 μl, 0.19 mmol). The reaction mixture is stirred at rt overnight. The solvent is removed under reduced pressure and the crude product is purified by silica gel column chromatography (hexane/EtOAc 3:1, 1% NEt3), affording pure ethyl (2-phenethyl-1,2,3,4-tetrahydro-pyrido[4,3-b]indol-5-yl)-acetate (37 mg) in 60% yield: tR (LC-2) 1.69 min; ESI-MS (pos. ion): m/z 363.26 [M+H]+ (calcd 362.46 for C23H26N2O2).
