(E)-3-[4-(Dimethylamino)benzylidene]-2,3-dihydro-1H,9H-pyrrolo[2,1-b]quinazolin-9-one

The title compound, C(20)H(19)N(3)O, was obtained by condensation of 2,3-dihydro-1H,9H-pyrrolo[2,1-b]quinazolin-9-one (alkaloid deoxyvasicinone, isolated from Peganum Harmala) with 4-(dimethylamino)benzaldehyde in the presence of sodium methoxide. The 2,3-dihydro-1H, 9H-pyrrolo[2,1-b]-quinazolin-9-one part of the molecule is roughly planar (r.m.s. deviation = 0.0178 angstrom) and is essentially coplanar with the benzilidene ring (r.m.s. deviation = 0.0080 angstrom), forming a dihedral angle of 5.0 (1)degrees. The crystal structure is stabilized by two aromatic pi-pi stacking interactions observed between the benzene rings of neighboring molecules [centroid-centroid distance = 3.7555 (19)angstrom.