5-Benzoyl-2-(1H-indol-3-yl)-4-[4-(propan-2-yl)phenyl]-4,5-dihydrofuran-3-carbonitrile

In the title compound, C29H24N2O2, the hydrofuran ring is twisted with puckering parameters Q = 0.1553 (16) Å and ϕ = 305.0 (6)°. In the crystal, the graph-set motifs of the interaction pattern are an R 2 2(16) motif involving dimers through N—H⋯N hydrogen bonds across centres of inversion and a C(6) motif through C—H⋯O hydrogen-bond between glide-related molecules. Together, these generate [101] ladder-like chains.

In the title compound, C 29 H 24 N 2 O 2 , the hydrofuran ring is twisted with puckering parameters Q = 0.1553 (16) Å and ' = 305.0 (6) . In the crystal, the graph-set motifs of the interaction pattern are an R 2 2 (16) motif involving dimers through N-HÁ Á ÁN hydrogen bonds across centres of inversion and a C(6) motif through C-HÁ Á ÁO hydrogen-bond between glide-related molecules. Together, these generate [101] ladder-like chains.
Data collection: APEX2 (Bruker, 2009); cell refinement: SAINT (Bruker, 2009); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: PLATON (Spek, 2009); software used to prepare material for publication: SHELXL97. In the molecule of the title compound ( Fig. 1), the puckering (Cremer & Pople, 1975) of the furan ring is twisted ( 4 T 5 ) about the C4-C5 bond with Q = 0.1553 (16) Å and φ = 305.0 (6)°. The geometry of the N-H···N and C-H···O interactions that characterize the crystal packing (Table 1) are similar to its 4-phenyl analogue (Suresh et al., 2012a). The graph-set motifs (Bernstein et al., 1995) that characterize the intermolecular interaction pattern are a R 2 2 (16) involving dimers through N-H···N hydrogen bonds across centres of inversion and a C(6) motif through C-H···O hydrogen-bond between glide-related molecules (Fig. 2). The crystal structure may be visualized as zero-dimensional N-H···N mediated centrosymmetric dimeric units linked via C-H···O linkages to form a supramolecular ladder parallel to the b axis that extends along the [101] direction (Fig. 3). The non-covalent crystal packing interactions are closely related to that observed in the 4-phenyl analogue and distinctly differs from those of the 4-methylphenyl (Suresh et al., 2012b) and 4bromophenyl (Suresh et al., 2012c) analogues. The intramolecular C-H···O hydrogen bond generates a S(6) motif and its geometry is similar to those observed in all of the above analogues. No significant weak non-covalent crystal packing interactions involving centroids of planar rings are observed. Though it has become an acceptable norm in describing weak non-covalent interactions in terms of C-H···π and π···π interactions, some recent views (Martinez & Iverson, 2012; Bloom & Wheeler, 2011) on these interactions calls for a careful analysis while describing them in crystal structures.
The crystal structure of the title compound together with those of its analogues demonstrate the effect of substituents in drastically altering the interaction patterns while retaining the crystal system and lattice type.

Experimental
To a stirred mixture of 2-(1H-indole-3-carbonyl)-3-(4-isopropylphenyl)acrylonitrile (1.0 eq) and phenacylpyridinium bromide (1.0 eq) in water (10 ml) was added drop wise triethylamine (0.25 eq) at room temperature. The resulting clear solution, that slowly became turbid, was stirred at room temperature for 1.5 h. Then the separated free flowing solid was filtered and washed with methanol (3 ml) to afford the compound as pale yellow solid. Yield 87%; m.p. 508 K.

Refinement
All hydrogen atoms except those participating in the hydrogen-bonding were included into the model at geometrically calculated positions (C-H target distance 0.96 Å for methyl hydrogen atoms, 0.93 Å for all others) and refined using a riding model. The torsion angle of the methyl groups involving C7 and C8 were allowed to refine. The U iso values of all hydrogen atoms were constrained to 1.2 times U eq (1.5 times for methyl H atoms) of the respective atom to which the hydrogen atom binds. The positions of the hydrogen atoms bound to N2, C33 and C56 were allowed to refine isotropically. A reflection (1 0 1) partially obstructed by the primary beam stop was omitted from the refinement.

Figure 1
The molecular structure of the title compound showing displacement ellipsoids drawn at the 50% probability level.

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.