2-(4-Methoxybenzyl)-4,6-diphenyl-2,5-diazabicyclo[2.2.2]oct-5-en-3-one

In the crystal structure of the title compound, C26H24N2O2, weak intermolecular C—H⋯π interactions involving the benzene of the p-methoxy benzyl group and one of the phenyl rings result in the formation of chains consisting of alternating enantiomers. Weak C—H ⋯O interactions with the methoxy O atom lead to the formation of layers, which are interlinked by further C—H⋯O interactions into a three-dimensional assembly.

In the crystal structure of the title compound, C 26 H 24 N 2 O 2 , weak intermolecular C-HÁ Á Á interactions involving the benzene of the p-methoxy benzyl group and one of the phenyl rings result in the formation of chains consisting of alternating enantiomers. Weak C-H Á Á ÁO interactions with the methoxy O atom lead to the formation of layers, which are interlinked by further C-HÁ Á ÁO interactions into a three-dimensional assembly.  Rombouts et al. (2003). For a crystal structure with a 2,5-diazabicyclo[2.2.2]oct-5-en-3-one core, see: Rusinov et al. (2009). For crystal structures with a similar 2,5-diazabicyclo[2.2.2]octane-3,6-dione core, see: Alen et al. (2007b); Holl et al.  Table 1 Hydrogen-bond geometry (Å , ).
The presented structure crystallizes in the triclinic space group P1 with one molecule in the asymmetric unit ( Fig. 1).
Experimental 1-(4-methoxybenzyl)-3,5-diphenylpyrazin-2(1H)-one (5 mmol) was dissolved in toluene and heated at 145 °C in a stainless steel bomb under ethene pressure (35 atm) for 4 h. The progress of the Diels-Alder cycloaddition was monitored on TLC, by the disappearance of the starting pyrazinone. After evaporation of the solvent, the crude residue was purified by column chromatography to yield the title compound. Single crystals suitable for X-ray diffraction were obtained by slow evaporation from a chloroform solution.

Refinement
All H atoms were positioned geometrically (C-H = 0.95, 0.98, 0.99 and 1 Å) and constrained to ride on their parent atoms with U iso (H) values set at 1.2 x U eq (C) and 1.5 x U eq (methyl-C).
supplementary materials sup-2 Figures Fig. 1. The molecular structure of the title molecule; displacement ellipsoids are drawn at the 50% probability level.   Table 1.