Synthesis of substituted azaoxindoles for the preparation of aza-tenidap analogs

The preparation of a set of eight azaoxindoles bearing substituents on the aromatic nucleus is outlined. These compounds were required for the preparation of aza-analogs of the anti-inflammatory oxindole tenidap. Two methods of synthesis were used, the first involving the addition of malonate to 2-chloro-3-nitropyridine derivatives followed by nitro group reduction and one-pot cyclization/hydrolysis/decarboxylation. The second method, utilizing the vicarious nucleophilic substitution (VNS) reaction of nitropyridine derivatives (followed by nitro group reduction and one-pot cyclization/hydrolysis), constitutes a novel route to azaoxindoles.