m-Chloroperbenzoic acid → 6-Ethylisatoic anhydride

Participants

Reaction Steps

20 g (0.114 mol) of 4-ethylisatin are suspended in 75 ml of 100 percent acetic acid, treated portionwise with 26 g (0.137 mol) of m-chloroperbenzoic acid, the temperature not rising above 50°, and then the mixture is stirred at this temperature for a further 15 minutes. The mixture is poured into ice-water and filtered. The crude product obtained is taken up in ethyl acetate and extracted cautiously with a mixture of 2 N sodium hydroxide and ice. The ethyl acetate phase is dried over magnesium sulphate and concentrated to give crude 6-ethylisatoic acid anhydride which melts at 202°-204° after recrystallization from ethyl acetate.

Provenance & Evidence