rac-(6S)-6-Hy­droxy-6-{2-[2-(propan-2-yl­idene)hydrazinyl­idene]prop­yl}indolo[2,1-b]quinazolin-12(6H)-one

The chiral title compound, C(21)H(20)N(4)O(2), crystallizes as a racemic mixture. In the crystal, mol­ecules form centrosymmetric π-overlapping dimers [inter­planar distance = 3.338 (6) Å], which are further connected along the a axis forming centrosymmetric dimers via O—H⋯N hydrogen bonds. C—H⋯O inter­actions are also observed. The indolo[2,1-b]quinazoline group is somewhat bent, with a small dihedral angle of 6.3 (4)° between the plane of the quinazoline system and the plane of the benzene ring of the indole moiety. The C=N—N=C atoms of the azine group is oriented almost perpendicular [84.1 (2)°] to the mean plane of the quinazoline system.