Reaction #3215

Reaction equation

6-iodo-1H-indole-2,3-dione

water

→

title compound

Yield 81.8%

7-Iodo-2H-3,1-benzoxazine-2,4(1H)-dione

Yield 81.8%

Solvents

acetic acid

acetic anhydride

Conditions

Workup

1. 1
   Temperaturewhile maintaining the temperature of the reaction mixture at 80°-90° C
2. 2
   Temperaturecooled
3. 3
   FiltrationThe resulting mixture was filtered
4. 4
   Otherthe collected solids dried

Procedure

To a stirred warm (80° C.) solution of 6-iodo-1H-indole-2,3-dione (3.0 g, 11 mM) in acetic acid (10 mL) and acetic anhydride (10 mL) was added in small portions chromium trioxide (1.83 g, 18.3 mM) while maintaining the temperature of the reaction mixture at 80°-90° C. The reaction mixture was then heated at 80° C. for 10 min, cooled and poured into water. The resulting mixture was filtered and the collected solids dried to provide the title compound as a yellow solid (2.6 g, 81.8%); MS(CI): 290 (M+H).

Source