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 mol­ecules of almost identical conformation in the asymmetric unit. The tricyclic core of schulzeine has a fused-three-ring system comprising the tetra­hydro­isoquinoline and δ-lactam moieties. In both mol­ecules, the pyridine ring adopts a twisted-boat conformation, whereas the lactam ring is in a boat conformation. The two meth­oxy groups are slightly twisted from the attached benzene ring [C—O—C—C torsion angles = −21.3 (2) and −20.5 (2)° in mol­ecule A, and −6.3 (2) and −16.2 (2)° in mol­ecule B] and the benzamide moiety is in a (−)-synclinal conformation with respect to the lactam ring. In the crystal, mol­ecules are linked into V-shaped dimers by inter­molecular N—H⋯O hydrogen bonds and weak C—H⋯O inter­actions. These dimers are stacked into V-shaped columns along the a axis. Adjacent columns are further linked in an anti­parallel manner. C—H⋯π inter­actions are also observed.