Dichloromethane → ethyl 5-bromo-3-formyl-1H-indole-2-carboxylate

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Reaction Steps

Oxalyl chloride (3.43 mL, 39.9 mmol) was added with stirring to DMF (30 mL) and CH2Cl2 (80 mL) at 0° C. After 20 min at 0° C., 5-bromoindole-2-carboxylic acid ethyl ester (10 g, 37.3 mmol) in DMF (80 mL), was added. The mixture was stirred at rt for 24 h and poured into NaHCO3 (aq, sat) and extracted with CH2Cl2. The combined extracts were washed with H2O and brine, dried (Na2SO4) and concentrated. Crystallisation from EtOH gave the sub-title compound. Yield 8.9 g (81%).

Provenance & Evidence