5′-Amino-1,3-dioxo-2′,3′-dihydro-7′H-spiro[indane-2,7′-thieno[3,2-b]pyran]-6′-carbonitrile 1′,1′-dioxide

The title compound, C16H10N2O5S, was synthesized via the condesation of dihydrothiophen-3(2H)-one 1,1-dioxide, 1H-indene-1,2,3-trione and malononitrile in ethanol. The 2,3-dihydrothiophene 1,1-dioxide and pyran rings adopt envelope conformations. The mean planes through the planar part of the pyran ring and the benzene ring are nearly perpendicular, forming a dihedral angle of 88.40 (7)°. The crystal packing is stabilized by intermolecular N—H⋯O and N—H⋯N hydrogen bonds with the sulfone O atom and the cyano N atom acting as acceptors.

The title compound, C 16 H 10 N 2 O 5 S, was synthesized via the condesation of dihydrothiophen-3(2H)-one 1,1-dioxide, 1Hindene-1,2,3-trione and malononitrile in ethanol. The 2,3dihydrothiophene 1,1-dioxide and pyran rings adopt envelope conformations. The mean planes through the planar part of the pyran ring and the benzene ring are nearly perpendicular, forming a dihedral angle of 88.40 (7) . The crystal packing is stabilized by intermolecular N-HÁ Á ÁO and N-HÁ Á ÁN hydrogen bonds with the sulfone O atom and the cyano N atom acting as acceptors.

Related literature
For the uses of thienopyranyl compounds such as thieno-[3,2-b]pyran derivatives as antiviral agents and -2C adrenoreceptor agonists, see: Chao et al. (2009);Friary et al. (1991). For puckering parameters, see: Cremer & Pople (1975 Table 1 Hydrogen-bond geometry (Å , ).  α-2 C adrenoreceptor agonists ( Chao et al., 2009). This led us to pay attention to the synthesis and bioactivity of these compounds. During the synthesis of thieno[3,2-b]pyran derivatives, the title compound, (I) was isolated and its structure was determined by X-ray diffraction. Here we report its crystal structure.
The molecular structure of (I) is shown in Fig. 1. In the molecular structure, the thiophene ring is in envelope conformation, for the deviation of C1 from the C2/C3/C4/S1 plane is 0.364 (3)Å with r.m.s. of 0.0056.

Refinement
The hydrogen atoms bonded to the nitrogen atom were positioned from a Fourier difference map. The N-H bond lengths were restrained to 0.90Å with an estimated standard deviation 0.01. The distance between H1C and H1D was restrained to 1.50Å with an estimated standard deviation 0.01. Other H atoms were placed in calculated positions, with C-H = 0.93 or 0.97 Å, and included in the final cycles of refinement using a riding model, with U iso (H) = 1.2U eq (parent atom).

Special details
Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds 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 Rfactors(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.