Reaktion #322469

Reaktionsgleichung

4,5-dichloroisatin

4,5-Dichloroisatin

H2O2

water

→

14e

Ausbeute 90.0%

5,6-Dichloroisatoic anhydride

Ausbeute 90.0%

Lösungsmittel

acetic acid

Reaktionsbedingungen

Aufarbeitung

1. 1
   Sonstigeformed a precipitate),
2. 2
   Temperaturto cool to 22° C.
3. 3
   FiltrationThe precipitate was filtered
4. 4
   Waschenwashed with water (6×10 mL)
5. 5
   Sonstigedried

Vorschrift

To a suspension of 4,5-dichloroisatin (13f, 216 mg, 1.0 mmol) in glacial acetic acid (5 mL) and 2 drops (about 0.02 mL) of conc H2SO4 was added 0.34 mL (about 3 mmol) of 30% H2O2. The mixture was stirred at 70° C. (bath) for 2.5 h (the mixture turned into a solution, then formed a precipitate), allowed to cool to 22° C. and cold water (10 mL) was added. The precipitate was filtered, washed with water (6×10 mL), dried to give 208 mg (90%) of 14e as an orange-yellow powder, mp 267°-9° C. (dec). IR, 1810, 1779, 1762, 1711, 1600, 1335, 1254, 1041, 1024 cm-1 ; 1H NMR δ 11.952 (bs, 1H), 7.928 (d, J=8.7 Hz, 1H), 7.110 (d, J=8.7Hz, 1H); HRMS Calcd for C8H3Cl2NO3 : 230.9490; Found: 230.9489.

Quelle