A solution of benzyl 3-chloro-1H-pyrrolo[3,2-c]pyridine-1-carboxylate 5-oxide (2.6 g, 8.53 mmol) in chloroform was treated dropwise with 2,4,4-trimethylpentan-2-amine (6.026 mL, 37.54 mmol) and stirred for about 15 minutes. The mixture was cooled to 0° C. followed by the portion wise addition of p-toluenesulphonyl chloride (3.578 g, 18.77 mmol). The reaction mixture was then stirred at room temperature for about 1 hour, diluted with dichloromethane and washed with saturated aq. sodium bicarbonate solution. The organic layer was separated, dried over anhydrous sodium sulfate and concentrated under vacuum to get viscous oil. The crude product was purified by silica gel column chromatography using ethyl acetate and hexane (1%) to yield benzyl 3-chloro-4-[(2,4,4-trimethylpentan-2-yl)amino]-1H-pyrrolo[3,2-c]pyridine-1-carboxylate (610.8 mg, 43%) as a pale yellow solid.
