1-Ethyl-3-(3'-dimethylaminopropyl)carbodiimide → 5-Chloro-1H-pyrrolo[2,3-c]pyridine-2-carboxylic acid N'-(tertbutyloxycarbonyl)hydrazide

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Reaction Steps

To a solution of 5-chloro-1H-pyrrolo[2,3-c]pyridine-2-carboxylic acid (Preparation 8, 2.05 g, 10.4 mmol) in DMF (30 mL), tert-butyl carbazate (1.38 g, 10.4 mmol), DIPEA (3.5 mL, 20.4 mmol), HOBt (1.58 g, 10.3 mmol) and EDCI (2.54 g, 13.3 mmol) were added successively. The resulting solution was stirred for 12 h at rt before adding water and brine (1:1, 200 mL). The solution was extracted with ethyl acetate (4×50 mL) and the combined organic layers were washed with dilute hydrochloric acid (1N, 50 mL), dilute sodium hydroxide solution (1N, 50 mL) and brine. The organic layer was dried (MgSO4) and concentrated in vacuo to give a solid residue, which was purified by flash chromatography on silica gel (hexane/ethyl acetate, 1:3) to give the title compound. δH (CDCl3): 1.42 (9H, s), 7.19 (1H, s), 7.78 (1H, s), 8.60 (1H, s), 9.28 (1H, br s).

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