Acetic Anhydride → Methyl 6-chloro-1H-indazole-4-carboxylate

Participants

Reaction Steps

To a stirred solution of methyl 3-amino-5-chloro-2-methylbenzoate (1 equiv.) in chloroform (13 mL per 1 mmol), potassium acetate (1.05 equiv.) and acetic anhydride (2 equiv.) were added and reaction mixture stirred at room temperature for 12 h. After this time, tert-butyl nitrite (4 equiv.) and 18-crown-6 (0.35 equiv.) were added and the reaction stirred again at 65° C. for 3 h. On completion, the reaction mixture was cooled to room temperature, diluted with chloroform (500 mL) and washed with sat. sodium bicarbonate solution. The organic layer was dried over sodium sulfate and concentrated to afford the title compound (yield 90-95%).

Provenance & Evidence