Crystal structure of 10-benzyl-9-(3,4-dimethoxyphenyl)-3,3,6,6-tetramethyl-3,4,6,7,9,10-hexahydroacridine-1,8(2H,5H)-dione

In the acridinedione moiety of the title compound, C32H37NO4, the central dihydropyridine ring adopts a flattened-boat conformation, with the N atom and the methine C atom displaced from the mean plane of the other four atoms by 0.0513 (14) and 0.1828 (18) Å, respectively. The two cyclohexenone rings adopt envelope conformations, with the tetrasubsituted C atoms as the flap atoms. The 3,4-dimethoxybenzene and benzyl rings are almost normal to the dihydropyridine mean plane, with dihedral angles of 89.47 (9) and 82.90 (11)°, respectively. In the crystal, molecules are linked via a pair of C—H⋯O hydrogen bonds, forming inversion dimers, which are, in turn, linked by C—H⋯O hydrogen bonds, forming slabs lying parallel to (001).


S1. Comment
\ Acridine derivatives with a dihydropyridine unit belong to a special class of compounds, which are important because of their wide range of applications in the pharmaceutical and dye industries. They are also well known as therapeutic agents (Nasim & Brychcy, 1979;Thull & Testa, 1994).
In the crystal, molecules are linked via a pair of C-H···O hydrogen bonds forming inversion dimers, which in turn are linked by C-H···O hydrogen bonds forming slabs lying parallel to (001); see Table 1 and Fig. 2

S3. Refinement
Crystal data, data collection and structure refinement details are summarized in Table 2. All the H atoms were identified from difference electron density maps and subsequently treated as riding atoms: C-H = 0.93 -0.98 Å with U iso (H) = 1.5U eq (C) for methyl H atoms and 1.2U eq (C) for other H atoms.

Figure 1
A view of the molecular structure of the title compound, with atom labelling. Displacement ellipsoids are drawn at the 30% probability level.

Figure 2
A view along the b axis of the crystal packing of the title compound. The C-H···O hydrogen bonds are shown as dashed lines (see Table 1).
10-Benzyl-9-(3,4-dimethoxyphenyl)-3,3,6,6-tetramethyl-3,4,6,7,9,10-hexahydroacridine-1,8(2H,5H)-dione Hydrogen site location: inferred from neighbouring sites H-atom parameters constrained where P = (F o 2 + 2F c 2 )/3 (Δ/σ) max = 0.002 Δρ max = 0.14 e Å −3 Δρ min = −0.14 e Å −3 Extinction correction: SHELXL97 (Sheldrick, 2008), Fc * =kFc[1+0.001xFc 2 λ 3 /sin(2θ)] -1/4 Extinction coefficient: 0.0024 (3) Special details Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes. Refinement. Refinement of F 2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F 2 , conventional R-factors R are based on F, with F set to zero for negative F 2 . The threshold expression of F 2 > σ(F 2 ) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F 2 are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger.