Isoquinoline-based polycyclic lactams such as isoindoloisoquinolinones, pyrroloisoquinolinones, and benzo[a]quinolizinones were successfully assembled from the corresponding imides by using a TfOH-mediated (TfOH = trifluoromethanesulfonic acid) imide carbonyl activation and cyclization strategy. By employing this simple method, the isoquinoline

Synthesis of Condensed Tetrahydroisoquinoline Class of Alkaloids by Employing TfOH-Mediated Imide Carbonyl Activation. -Racemic erythrinarbine (IVb) and further tricyclic lactams (II) and (IV) are readily prepared via a TfOH-mediated cyclization reaction. The reduction of lactam (IVc) with LiAlH 4 leads to racemic crispine A (V). The regioselectivity of the cyclization of unsymmetrical N-phenethylphthalimides depends on the structure of substrates. -(SELVAKUMAR, J.; RAO, R. S.; SRINIVASAPRIYAN, V.; MARUTHEESWARAN, S.; RAMANATHAN, C. R.; Eur. J. Org. Chem. 2015, 10, 2175-2188, http://dx.

In the title compound, C24H21NO2, the residues at the central ethyl­ene bridge are trans to each other. The dihedral angles between the pyridine and benzene rings are 67.09 (6) and 61.41 (5)°. In the crystal, centrosymmetrically related mol­ecules are linked into dimers by pairs of C—H⋯O hydrogen bonds.