2-[4-(Piperidin-1-yl)-5H-chromeno[2,3-d]pyrimidin-2-yl]phenol

In the title compound, C22H21N3O2, the pyrimidine ring is essentially planar [maximum deviation = 0.018 (2) Å] and forms dihedral angles of 22.70 (8) and 0.97 (7)°, respectively, with the fused benzene ring and the hydroxy-substituted benzene ring. The piperidine ring has a chair conformation and the pyran ring has a flattened twist-boat conformation. The hydroxy group was refined as disordered over two sets of sites in a 0.702 (4):0.298 (4) ratio. The disorder corresponds to a rotation of approxomiately 180° about the C—C bond connecting the phenol group to the pyrimidine ring and hence, both the major and minor components of disorder form intramolecular O—H⋯N hydrogen bonds. In the crystal, pairs of weak C—H⋯π interactions form inversion dimers. In addition, π–π interactions are observed between the pyrimidine ring and the hydroxy-substituted benzene ring [centroid–centroid separation = 3.739 (2) Å].

In the title compound, C 22 H 21 N 3 O 2 , the pyrimidine ring is essentially planar [maximum deviation = 0.018 (2) Å ] and forms dihedral angles of 22.70 (8) and 0.97 (7) , respectively, with the fused benzene ring and the hydroxy-substituted benzene ring. The piperidine ring has a chair conformation and the pyran ring has a flattened twist-boat conformation. The hydroxy group was refined as disordered over two sets of sites in a 0.702 (4):0.298 (4) ratio. The disorder corresponds to a rotation of approxomiately 180 about the C-C bond connecting the phenol group to the pyrimidine ring and hence, both the major and minor components of disorder form intramolecular O-HÁ Á ÁN hydrogen bonds. In the crystal, pairs of weak C-HÁ Á Á interactions form inversion dimers. In addition,interactions are observed between the pyrimidine ring and the hydroxy-substituted benzene ring [centroidcentroid separation = 3.739 (2) Å ].

Comment
Benzopyrano[2,3-d]pyrimidines have gained much attention as significant medicinal scaffolds due to their inherent and multidirectional pharmaceutical potentials that include anti-inflammatory, analgesic, and anti-aggregating activities (Bruno et al., 2001(Bruno et al., ,2004. More importantly, such chemical entities have been found to exhibit potent in vivo antitumor as well as in vitro cytotoxic activity against various cancer cell lines causing considerable degree of perturbation in cell cycle kinetics (Hadfield et al., 1999). Very recently, we have developed a straight forward and efficient pseudo fourcomponent one-pot synthesis of diverse benzopyrano[2,3-d]pyrimidine scaffolds in good yields using commercially available sodium formate as an inexpensive and non-toxic catalyst (Brahmachari & Das, 2014). Herein, we wish to report the environmentally benign one-pot synthesis and X-ray crystal structure of 2-(4-(piperidin-1-yl)-5H-chromeno[2,3-  (Duax & Norton, 1975). The hydroxy group was refined as disordered over two sets of sites in a 0.702 (4): 0.298 (4) ratio. The disorder corresponds to a rotation of approxomiately 180° about the C2-C21 bond and hence, both the major and minor components of disorder form intramolecular O-H···N hydrogen bonds (see Table 1). In the crystal, pairs of weak C-H···π interactions form inversion dimers. In addition, π-π interactions are observed between the pyrimidine ring and hydroxy-substituted benzene ring [centroid-centroid seperation = 3.739 (2) Å, interplanar spacing = 3.534 Å, centriod shift = 1.22 Å, symmetry code: 1 -x,1 -y,1 -z]. The crystal packing is shown in Fig. 2.

Experimental
Infrared spectra were recorded using a Shimadzu (FT-IR 8400S) FT-IR spectrophotometer using KBr disc. 1H and 13 C NMR spectra was obtained at 400 and 100 MHz, respectively, using Bruker DRX spectrometer and CDCl 3 and DMSO-d6 as solvents. Elemental analysis was performed with an Elementar Vario EL III Carlo Erba 1108 micro-analyzer instrument. Melting point was recorded on a Sunvic melting point apparatus and is uncorrected. TLC was performed using silica gel 60 F254 (Merck) plates. An oven-dried screw cap test tube was charged with a magnetic stir bar, salicylaldehyde (2 mmol), malononitrile (1 mmol), piperidine (1 mmol), and sodium formate (10 mol%) in 4 ml e thanol. The reaction mixture was stirred at room temperature for 12 h. On completion of the reaction as monitored by TLC, the product was precipitated out and filtered; the filtrate was preserved for reuse. The crude residue was washed with water followed by ethanol to obtain pure product 1, characterized by elemental analyses as well as spectral studies including FT supplementary materials sup-2 Acta Cryst. (2014). E70, o447-o448 -IR, 1H-NMR and 13 C-NMR. The title compound (50 mg) was dissolved in 10 ml DMSO and left for several days at ambient temperature which yielded single crystals suitable for X-ray diffraction.

Refinement
All H atoms were geometrically fixed and allowed to ride on their parent atoms, with C-H distances of 0.93-0.97 Å, O -H = 0.82Å and with U iso (H) = 1.2U eq (C) or U iso (H) = 1.5U eq (O).

Figure 1
The molecular structure of (I) with ellipsoids drawn at the 40% probability level. H atoms are shown as small spheres of arbitrary radii. Both disorder components are shown.  Part of the crystal structure with hydrogen bonds shown as dashed lines. Only the H atoms involved in hydrogen bonds and weak C-H···π interactions are shown.

2-[4-(Piperidin-1-yl)-5H-chromeno[2,3-d]pyrimidin-2-yl]phenol
Crystal data 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 )
x y z U iso */U eq Occ. (