To a solution of 2-(2-oxo-piperazin-1-ylmethyl)-pyrrolo[3,2-c]pyridine-1-carboxylic acid tert-butyl ester (0.10 g, 0.30 mmol) in acetonitrile (5 mL) is added 4-(5-chloro-thiophen-2-yl)-benzaldehyde (0.067 g, 0.30 mmol) followed by triacetoxyborohydride (0.13 g, 0.60 mmol) and glacial acetic acid (1 drop). The resulting mixture is stirred at room temperature overnight then poured into EtOAc and washed with water (×2) and brine. The organic layer is dried over MgSO4, filtered and concentrated to dryness then purified by column chromatography using EtOAc as the eluent to yield the title compound (0.90 g, 0.17 mmol). ESI MS [M+H]+=537.
