InCl3-catalyzed three-component reaction: a novel synthesis of dihydropyrano[3,2-b]chromenediones under solvent-free conditions

Three-component coupling (3CC) of kojic acid, aldehyde and 1,3-dione has been achieved in the presence of 10 mol % InCl3 under solvent-free conditions to afford the corresponding dihydropyrano[3,2-b]chromenedione derivatives in good yields. This is the first example of the condensation of kojic acid, aldehyde and 1,3-diones to provide a novel series of kojic acid derivatives.