A one-pot, multicomponent tandem synthesis of fused polycyclic pyrrolo[3,2-c]quinolinone/pyrrolizino[2,3-c]quinolinone hybrid heterocycles via environmentally benign solid state melt reaction

Structurally diverse fused polycyclic pyrrolo[3,2-c]quinolinone/pyrrolizino[2,3-c]quinolinone hybrids were synthesized to get excellent yields via a tandem multi-component reaction sequence employing an environmentally benign solid state melt reaction involving [3+2]-cycloaddition process followed by two consecutive annulation steps. Baylis-Hillman products, used as dipolarophiles, were synthesized from various substituted aryl/heteroaryl aldehydes in the presence of DABCO and methyl acrylate, while the 1,3-dipole component was derived in situ from indoline-2,3-dione and acyclic/cyclic amino acid viz N-methylgylcine/l-proline. The structure of the unusual tandem products was unambiguously assigned by spectroscopic and XRD analysis. The products arose through the formation of three new rings, five new bonds, and three adjoining stereocenters with complete diastereomeric control.