Whole-molecule disordered (E)-2-(1-hydroxy-3-phenylprop-2-en-1-ylidene)-4,5-dimethoxycyclopent-4-ene-1,3-dione isolated from Lindera oxyphylla (Lauraceae)

In the molecule of the title compound, C16H14O5, all non-H atoms are approximately co-planar [maximum atomic deviation = 0.064 (5) Å]. The hydroxy group is a hydrogen-bond donor to a carbonyl O atom. Weak intermolecular C—H⋯O hydrogen bonding is present in the crystal structure. The crystal structure is ’whole-molecule disordered’ about an axis that runs approximately along the length of the molecule; the occupancy of the two disorder components was set as exactly 0.5. An intramolecular O—-H⋯O hydrogen bond exists in each component.

In the molecule of the title compound, C 16 H 14 O 5 , all non-H atoms are approximately co-planar [maximum atomic deviation = 0.064 (5) Å ]. The hydroxy group is a hydrogen-bond donor to a carbonyl O atom. Weak intermolecular C-HÁ Á ÁO hydrogen bonding is present in the crystal structure. The crystal structure is 'whole-molecule disordered' about an axis that runs approximately along the length of the molecule; the occupancy of the two disorder components was set as exactly 0.5. An intramolecular O--HÁ Á ÁO hydrogen bond exists in each component.
exists as a planar molecule (Syah et al., 2005). Linderone is similarly a planar molecule; however, the molecule is 'wholemolecule' disordered ( Fig. 1) about an axis that runs approximately along the length of the flat molecule. The three-atom chain connecting the five-membered and six-membered rings exists in an E-configuration; the hydroxy group is hydrogenbond donor to the carbonyl O atom.

Refinement
Carbon-and oxygen-bound H-atoms were placed in calculated positions [C-H 0.95 to 0.98. O-H 0.84 Å, U iso (H) 1.2 to 1.5U eq (C,O)], and were included in the refinement in the riding model approximation. An sp 2 -type of hybridization was assumed for the hydroxy H atom.
The crystal structure is a 'whole-molecule disordered' crystal structure. As the occupancy refined to near 1:1, the occupancy of the two disorder components was set as exactly 0.5.
The phenyl ring was refined as a rigid hexagon of 1.39 Å sides and the five-membered ring a rigid pentagon of 1.42 Å sides. The temperature factors of the atoms constituting the five-membered ring were set to those of the umprimed ones, and the anisotropic temperature factors were restrained to be nearly isotropic.
The extinction was refined; although the value is small, its refinement improved the refinement somewhat.
The crystal used for the measurements was a twinned crystal of low mosaicity; fortunately, the presence of the minor twin component did not affect the diffraction intensities of the major component only the diffraction intensities of the major supplementary materials sup-2 component were integrated. On the other hand, the simultaneous integration of both components lead to a less satisfactory refinement. Other crystals were also measured but these demonstrated varying mosaicities and degrees of twinning (from 0 to 50%), and neither were the refinements improved by the use of copper radiation in place of molybdenum radiation. Fig. 1. Thermal ellipsoid plot (Barbour, 2001) of one of the whole-molcule disordered components of C 16 H 14 O 5 at the 70% probability level; hydrogen atoms are drawn as spheres of arbitrary radius.