N-(9,11-Dimeth­oxy-4-oxo-2,3,4,6,7,11b-hexa­hydro-1H-pyrido[2,1-a]isoquinolin-3-yl)benzamide

The title schulzeine derivative, C(22)H(24)N(2)O(4), crystallizes with two crystallographically independent mol-ecules of almost identical conformation in the asymmetric unit. The tricyclic core of schulzeine has a fused-three-ring system comprising the tetra-hydro-isoquinoline and δ-lactam moieties. In both mol-ecules, the pyridine ring adopts a twisted-boat conformation, whereas the lactam ring is in a boat conformation. The two meth-oxy groups are slightly twisted from the attached benzene ring [C-O-C-C torsion angles = -21.3 (2) and -20.5 (2)° in mol-ecule A, and -6.3 (2) and -16.2 (2)° in mol-ecule B] and the benzamide moiety is in a (-)-synclinal conformation with respect to the lactam ring. In the crystal, mol-ecules are linked into V-shaped dimers by inter-molecular N-H⋯O hydrogen bonds and weak C-H⋯O inter-actions. These dimers are stacked into V-shaped columns along the a axis. Adjacent columns are further linked in an anti-parallel manner. C-H⋯π inter-actions are also observed.