Four component synthesis of pyrrolo[3,2-c]pyridin-4-one derivatives.

• A new domino approach for synthesis of pyrrolo[3,2- c pyridin-4-ones has been established. • The one-pot two-step four component strategy makes the reaction attractive. • The remarkable feature of the process is the formation of five C–N, C–C bonds initiated by sole acetic acid. A direct and metal-free access toward poly-substituted pyrrolo[3,2- c pyridin-4-one and its analogues have been established through a simple four-component, two-step reaction of 4-hydroxy-6-methyl-2 H -pyran-2-one, two amine molecules, and β -nitrostyrenes. The reaction allows the formation of five different C–N, C–C bonds by the multiple bond cleavage only using acetic acid as catalyst and solvent. The advantages of broad substrate scope, efficient and metal-free reaction conditions, inexpensive and readily available starting materials as well as simple one-pot two-step operation, make the strategy highly attractive. This transformation in acetic acid resulted in the rapid establishment of functional bioactive poly-substituted pyrrolo[3,2- c pyridin-4-one derivatives. [ABSTRACT FROM AUTHOR]