Crystal structure of 2-(11-oxo-10H,11H-indeno[1,2-b]chromen-10-yl)-2,3-dihydro-1H-indene-1,3-dione

In the title molecule, C25H14O4, the fused-ring system consisting of four rings is approximately planar, with a dihedral angle of 9.62 (5)° between the planes of the indene ring system and the benzene ring. The dihydroindene-1,3-dione unit makes a dihedral angle of 63.50 (2)° with the mean plane of the fused-ring system. A weak C—H⋯O interaction organizes the molecules into a helical chain along the b axis. In addition, there is a π–π stacking interaction between the five-membered rings of adjacent fused-ring systems, with a centroid–centroid distance of 3.666 (1) Å.


S1. Comment
The synthesis of chromenes scaffolds has attracted considerable attention from organic and medicinal chemists for many years as larg number of natural products contain this heterocyclic nucleus (RamaGanesh et al., 2010). They are widely used as additives in food, perfumes, cosmetics, pharmaceuticals (O′Kenedy & Thornes, 1997), optical brighteners, dispersed fluorescent and laser dyes (Zabradnik, 1992). Fused chromene ring systems have platelet anti-aggregating, local anesthetic (Bargagna et al., 1992) and also exhibit antidepressant effects (Ermili et al., 1979). In this view and following to our study in synthesis of bio-active hetero-cyclic molecules, we report in this study the synthesis and crystal structure of the title compound.

S2. Experimental
In 30 ml of ethanol, a mixture of 1 mmol (122 mg) of salicylaldehyde and 2 mmol (292 mg) of 1H-indene-1,3(2H)-dione has been refluxed in the presence of a guanidine derivative as a lewise base catalyst. The reaction was monitored by TLC till completion after 5 h. On cooling, the solid product was collected by filteration, dried under vacuum and recrystallized from dimethylformamide (DMF). Single crystals suitable for X-ray diffraction were obtained by further crystallization from DMF. M.p. 513 K.

S3. Refinement
H-atoms were placed in calculated positions (C-H = 0.95-1.00 Å) and included as riding contributions with isotropic displacement parameters 1.2 times those of the attached carbon atoms.

Figure 1
The molecular structure of the title compound with labeling scheme and 50% probability ellipsoids.

Figure 2
A packing diagram of the title compound, showing a chain structure formed by C-H···O interactions (dashed lines).  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. H-atoms were placed in calculated positions (C-H = 0.95 -1.00 Å) and included as riding contributions with isotropic displacement parameters 1.2 times those of the attached carbon atoms.