Multicomponent Ugi Reaction of Indole- N-carboxylic Acids: Expeditious Access to Indole Carboxamide Amino Amides.

A novel multicomponent Ugi-type reaction for the synthesis of indole carboxamide amino amides from aldehydes, amines, isocyanides, and indole- N-carboxylic acids, which were simply prepared from indoles and CO2, is described. This method provides an expeditious and practical access to indole tethered peptide units, along with the achievement of remarkable structural diversity and brevity. Gram-scale reaction was conducted to demonstrate the scalability, and the products could be transformed to new indole derivatives.