(6aS*,6bS*,11R*,11aR*)-6-(2-Furylmethyl)-5,12-dioxo-5,6,6a,6b,7,11,11a,12-octahydrofuro[3′,2′:5,6]isoindolo[2,1-a]quinazoline-11-carboxylic acid

Abstract

The title compound, C23H18N2O6, is the product of an intramolecular thermal cycloaddition within 1-malein-2-[(E)-2-(2-furyl)vinyl]-4-oxo-3,4-dihydroquinazoline. The molecule comprises a previously unknown fused pentacyclic system containing two five-membered rings (2-pyrrolidinone and furan) and three six-membered rings (benzene, 2,3-dihydro-4-pyrimidinone and dihydrocyclohexane). The central five-membered pyrrolidinone ring has the usual envelope conformation. The six-membered dihydropyrimidinone and dihydrocyclohexane rings adopt a half-boat and a half-chair conformation, respectively. The dihedral angle between the planes of the terminal benzene and furan rings is 45.99 (7)°. In the crystal, O—H...O hydrogen bonds link the molecules into centrosymmetric dimers. Weak C—H...O hydrogen bonds consolidate further the crystal packing, which exhibits π–π interactions, with a short distance of 3.556 (3) Å between the centroids of benzene rings of neighbouring molecules.