Hydrochloric Acid → 6-Chloro-3-(2-thenoyl)-4-azaoxindole

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Reaction Steps

Pellets of sodium metal (3.4 g, 0.15 mmol) were added to dry ethanol (90 mL) in a dry round-bottomed flask. When dissolution of the sodium was complete, solid 6-chloro-4-azaoxindole (5.0 g 29.7 mmol) was added followed by ethyl 2-thiophenecarboxylate (8 mL, 55 mmol). The mixture was heated under nitrogen at reflux overnight during which a precipitate formed. The mixture was cooled, poured into ice/water and acidified to pH 3 with 6N HCl solution. The solid azaoxindole (7.8 g, 94%) (m.p. 250°) was collected by filtration washing with water and ether and dried in vacuo with heating.

Provenance & Evidence