A new strategy for the synthesis of 3-hydroxy-3-cyanomethyl-2-oxindoles and 3,3′-dicyanomethyl-2-oxindoles
in a reaction of isatin with ethyl cyanoacetate by Krapcho dealkoxycarbonylation reaction
in aqueous media is demonstrated. The reaction provides an easy access to synthetically
and medicinally valuable oxindole alkylnitriles in good to very good yields. Wider
substrate scope and operationally simple experimental procedures are highlighted features
of the developed protocol. Based on control experiments, a plausible mechanism of
reaction and synergistic effect of water is also rationalized.
Key words
aldol-type cyanomethylation - dealkoxycarbonylation - 3,3′-disubstituted oxindole
- ethyl cyanoacetate - isatin
