(E)-2-Hydroxycinnamaldehyde

The asymmetric unit of the title compound, C9H8O2, contains two independent molecules, both of which are essentially planar (r.m.s. deviations = 0.0294 and 0.0284 Å). The C=C double bond is in an E conformation and the vinylaldehyde groups adopt extended conformations. In the crystal, molecules are linked by O—H⋯O hydrogen bonds, forming infinite chains parallel to [101].

The asymmetric unit of the title compound, C 9 H 8 O 2 , contains two independent molecules, both of which are essentially planar (r.m.s. deviations = 0.0294 and 0.0284 Å ). The C C double bond is in an E conformation and the vinylaldehyde groups adopt extended conformations. In the crystal, molecules are linked by O-HÁ Á ÁO hydrogen bonds, forming infinite chains parallel to [101].  Table 1 Hydrogen-bond geometry (Å , ). supplementary materials Acta Cryst. (2013). E69, o534 [doi:10.1107/S1600536813006648]

(E)-2-Hydroxycinnamaldehyde
Ki-Tae Kang and Sung-Gon Kim Comment 2-Hydroxycinnamaldehyde, isolated from the stern bark of Cinnamonum cassia, and its synthetic derivatives have been shown to inhibit on farnesyl protein transferase in vitro, as well as angiogenesis, and tumor cell growth (Kwon et al. 1996;Lee et al. 1999;Ka et al. 2003). In view of these potential applications and in continuation of our work, the structure of the title compound has been determined and the results are presented here.
X-ray analysis confirms the molecular structure and atom connectivity as illustrated in Fig (Table 1).

Experimental
A solution of 2-hydroxybenzaldehyde (10.0 mmol) and vinyl acetate (11.0 mmol) in CH 3 CN (20 ml) was added to a stirred suspension of K 2 CO 3 in CH 3 CN (30 ml). After refluxing for 48 h, the reaction mixture was poured into cold water and diluted with EtOAc. The organic layer was washed with 10% NaOH solution, and the aqueous layer was separated, acidified with 10% HCl solution, and extracted with CH 2 Cl 2 . The resultant organic layer was dried over MgSO 4 and concentrated in vacuo. The dark residue was purified by silica gel chromatography to afford the title compound ( Fig. 2).
Crystals suitable for X-ray analysis were obtained by slow evaporation from an n-hexane/CH 2 Cl 2 solution.

Refinement
All H atoms were positioned geometrically (O-H = 0.84 Å and C-H = 0.95 Å) and constrained to ride on their parent atoms, with U iso (H) = 1.2U eq (C) or U iso (H) = 1.5U eq (O). The orientations of the H atoms in the hydroxyl groups were refined using a rotating rigid group approximation.  A view of the molecular structure of the title compound, showing the atom-numbering scheme. Displacement ellipsoids are drawn at the 50% probability level.

Figure 2
The preparation of the title compound. 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 C1