3-Benzylidene-6-methoxychroman-4-one

In the title compound, C17H14O3, the dihedral angle between the phenyl ring and the benzene ring of the chromanone moiety is 67.78 (3)°. The six-membered heterocyclic ring of the chromanone moiety adopts a half-chair conformation. The structure is stabilized by weak intermolecular C—H⋯O interactions that link the molecules into inversion dimers.

In the title compound, C 17 H 14 O 3 , the dihedral angle between the phenyl ring and the benzene ring of the chromanone moiety is 67.78 (3) . The six-membered heterocyclic ring of the chromanone moiety adopts a half-chair conformation. The structure is stabilized by weak intermolecular C-HÁ Á ÁO interactions that link the molecules into inversion dimers.
The geometric parameters in the title compound agree with values reported for a similar structure (Suresh et al., 2007).
The dihedral angle between the benzene ring of the chromanone moiety and the phenyl ring is 67.78 (3)°. The Chromanone moiety is fused with a six membered heterocyclic ring and the study of torsion angles, asymmetry parameters and least-square plane calculations shows that the chromanone adopts a half chair conformation with a deviation of C14 from the C8/C9/C15/C16/O2 plane by 0.616 (4) Å, Q 2 = 0.4053 (14) Å, Q 3 = -0.2052 (13)Å, and Q T =0.4543 (14)Å (Cremer &Pople, (1975). The structure is stabilized by weak intermolecular C-H···O interaction that link the molecules into pairs around a center (Table 1). No other short intermolecular interactions were found.
The reaction mixture was acidified and the precipitated acid was purified by recrystalization. Finally the acid was treated with triflouroacetic anhydride and the reaction mixture was refluxed in dichloro-methane for 1 hr. It was further purified by column chromatography (silica gel-3% ethyl acetate -hexane) and the crystals used for data collection were obtained by slow evaporation from methanol.

S3. Refinement
H atoms were positioned geometrically and refined using riding model,with C-H = 0.93 Å and U iso (H) = 1.2U eq (C) for aromatic C-H, C-H = 0.97 Å and U iso (H) = 1.2U eq (C) for CH2, C-H = 0.96 Å and U iso (H) = 1.5U iso (C) for CH3.  ORTEP of the molecule with atoms represented as 30% probability ellipsoids. 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 Rfactors based on ALL data will be even larger.