Methyl chloroformate → Ethyl 6-chloro-1H-pyrrolo[2,3-b]pyridine-2-carboxylate

Beteiligte Stoffe

Reaktionsschritte

To a stirred solution of ethyl 7-azaindole-2-carboxylate-7-oxide (1.32 g, 6.4 mmol) and hexamethyldisilazale (1.4 mL, 6.6 mmol) in THF (30 mL) at 0° C. was added dropwise over 30 min a solution of methyl chloroformate (1.2 mL, 15.5 mmol) in THF (5 mL). The mixture was warmed to room temperature, stirred for 2 h and partitioned between ether (50 mL) and water (50 mL). The aqueous layer was extracted with ether (30 mL). The combined organic extracts were washed (water, brine), dried (sodium sulfate) and purified by column chromatography [SiO2; heptane-ether (3:1)] to give ethyl 6-chloro-7-azaindole-2-carboxylate as a white solid (0.38 g, 26%). mp 144–145° C. Found: C, 53.69; H, 4.05; N, 12.39%. C10H9N2ClO2 requires: C, 53.47; H, 4.04; N, 12.46%.

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