Acetic Anhydride → 1H-Indazole-4-carboxylic acid, 1-acetyl-6-bromo-, methyl ester

Participants

Reaction Steps

To a stirred solution of methyl 3-amino-5-bromo-2-methylbenzoate (15 g, 61.5 mmol) in chloroform (150 mL), was added potassium acetate (6.32 g, 64.4 mmol) and acetic anhydride (12.6 g, 122.9 mmol) and reaction mixture was stirred at room temperature for 12 h. After this time, tert-butyl nitrite (25.3 g, 246.1 mmol) and 18-crown-6 (5.7 g, 21.5 mmol) were added and reaction stirred again at 65° C. for 3 h. On completion, the reaction mass 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 (18 g, 98.3%).

Provenance & Evidence