5-Fluoro-6′H,7′H,8′H-spiro[indoline-3,7′-pyrano[3,2-c:5,6-c′]di-1-benzopyran]-2,6′,8′-trione

In the title compound, C26H12FNO6, the central pyran ring and both benzopyran systems are nonplanar, having total puckering amplitudes of 0.139 (2), 0.050 (1) and 0.112 (2) Å, respectively. The central pyran ring adopts a boat conformation. The crystal structure is stabilized by C—H⋯O, N—H⋯O, N—H⋯F and C—H⋯π interactions.

After completion of the reaction as evident from TLC, the precipitated solid was filtered and washed with water to afford the product which was recrystallized from ethanol to provide colourless crystals. Yield 72%, m.p. 541-543 K.

Refinement
The N1-H atom was located in a difference map and refined with an N-H distance restraint of 0.86±0.01 Å. The Cbound H atoms were placed at calculated positions and allowed to ride on their carrier atoms with C-H = 0.93 Å,and with U iso = 1.2U eq (C).

Figure 1
The molecular structure of (I), showing 50% probability displacement ellipsoids and the atom-numbering scheme.

Data collection
Bruker Kappa APEXII diffractometer Radiation source: fine-focus sealed tube Graphite monochromator Detector resolution: 0 pixels mm -1 ω and φ scans Absorption correction: multi-scan (SADABS; Sheldrick, 1996) T min = 0.973, T max = 0.978 15720 measured reflections 5504 independent reflections 4486 reflections with I > 2σ(I) 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.
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å 2 )