Acetic Anhydride → 5-Fluoroisatoic anhydride

Participants

Reaction Conditions

Reaction Steps

Acetic anhydride (90.0 mL), 5-fluoroisatin (20.62 g, 0.125 mmol, 1.00 eq), and acetic acid (90 mL) were added to a 250 mL, three neck flask fitted with a magnetic stir bar and a condenser. The flask was placed in a water bath and heated to 85° C. Chromium (VI) oxide (20.36 g, 0.204 mol, 1.63 eq) was added in small portions (0.5 g size) over 40 min to the red solution. The reaction mixture was stirred for an additional 15 min and cooled to 10° C. in an ice bath. The solid that formed was isolated by filtration. Washing with 400 mL of water removed most of the green color. The solid was taken up in 300 mL of 2:1 acetic acid/water, refiltered, and dried overnight in a 50° C. vacuum oven. The 5-fluoroisatoic anhydride was isolated as a bright yellow solid (14.45 g, 64%). ##STR5##

Provenance & Evidence