Catalyst-free aldol condensation of ketones and isatins under mild reaction conditions in DMF with molecular sieves 4 angstrom as additive

In the presence of molecular sieve (MS) 4 angstrom in DMF, a catalyst-free aldol condensation of a variety of aromatic and aliphatic ketones with isatins under mild reaction conditions has been developed. This approach may provide access to a wide range of 3-substituted-3-hydroxyindolin-2-ones in good to excellent yields.