Synthesis and reactivity of new amide-substituted oxindole derivatives

Oxindole derivatives are of growing importance in organic synthesis and in the synthesis of biologically active compounds, therefore, a very important goal is to develop new ways of modifying such scaffold. In this article we proposed a general approach to synthesis of oxindole-based amide-substituted compounds, which includes usage of protecting group. To stabilize the key-molecule for further modifications – amino-isatin, the carbonyl group in the 3-position of the starting nitro-isatin was protected by ketal synthesis. Next, the reduction of nitro-group and further modification of amino-group was carried out. The proposed strategy allows us to obtain mono- and diamido-substituted isatins. The possibility of their modification in the 3-position for synthesis of potent biologically active compounds is demonstrated.