Sodium Hydroxide → (2-Benzoyl-4,5-dichloro-1 H-indol-3-yl)acetic Acid

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Reaction Steps

To a suspension of ethyl 4,5-dichloroindole-2-carboxylate (Ishii et al., Chem. Pharm. Bull., 1974, 22, 1981., 1.8 g, 7.0 mmol) in ethanol (40 ml) was added 2N aqueous NaOH (10 ml) and the mixture was heated at reflux temperature for 2 h. The mixture was cooled to room temperature and concentrated. The residual solid was acidified with 2N aqueous HCl (30 ml) and extracted with diethyl ether (80 ml×2). The organic extracts were dried (MgSO4) and concentrated to give 1.5 g (94%) of the title compound as yellow solids.

Provenance & Evidence