Nitric Acid → 6-Nitro-2,3-dihydro-1,4-benzodioxine-5-carboxylic acid

Participants

Reaction Conditions

Reaction Steps

1,600 ml of acetic acid, 1,600 ml of acetic anhydride, and 1000 g of 1,4-benzodioxane-5-carboxylic acid were introduced in a 6-liter balloon flask provided with an agitator and a thermometer. The mixture was heated to 40° C. and a solution of 400 ml of nitric acid in 400 ml of acetic acid was added. After the introduction, the mixture was stirred at 40°-45° C. for two hours and then cooled to 5° C. The precipitate was dried off, washed with 600 ml of acetic acid and then with water and dried at 40° C. 700 g of 7-nitro-1,4-benzodioxane-5-carboxylic acid were collected, the structure of which was confirmed by nuclear magnetic resonance (M.P: 246° C.). The mother liquors were diluted with 25 liters of water and the obtained precipitate was dried off, washed with water and dried. 6-nitro-1,4-benzodioxane-5-carboxylic acid was obtained (M.P.: 188° C.).

Provenance & Evidence