6-Chloroisatin

215959-30-1

6341-92-0

Step 2: 6-Chloroindirubin 3,3-dibromo-6-chloro-1,3-dihydro-indol-2-one (21.34 g, 59.7 mmol) was suspended in a 4:1 (v:v) solvent mixture of methanol and water (172 mL of methanol and 43 mL of water) and heated and refluxed for 19 hours. Upon completion of the reaction, the mixture was cooled in an ice bath and subsequently filtered. The resulting red solid was washed once with cold methanol and dried to give 6-chloroindole-2,3-dione (10.49 g, 88% yield). The product was confirmed to be structurally consistent by NMR hydrogen spectroscopy (400 MHz, DMSO-d6). Mass spectrometry analysis (API-ES+) showed m/z 182/184 [M+H]+, consistent with a characteristic peak containing one chlorine atom.