Electrosynthesis of N-Methylisatin.

Isatin in a solution of dry N,N-dimethylformamide/NaClO is electroreduced in the presence of CHI. N-methylisatin (NMI) is obtained in quantitative molar yield and high current efficiency by controlled potential electrolysis (CPE). NMI and N-methylisatoic anhydride are the reaction products when CPE is performed in the absence of CHI, but adding it once the CPE was completed.