3-Benzyl-5,7-dimethoxychroman-4-ol

In the crystal structure of the title compound, C18H20O4, O—H⋯O hydrogen bonds connect the molecules in parallel layers along the b axis.

In the crystal structure of the title compound, C 18 H 20 O 4 , O-HÁ Á ÁO hydrogen bonds connect the molecules in parallel layers along the b axis.

Related literature
For analogous structures, see Koch et al. (1994); Porter et al. (1985). For the biological activity of naturally ocurring homoisoflavanones that possess a 3-benzyl-substituted chroman ring system, see: Zhang et al. (2008). For our work on the synthesis and characterization of natural products from this family of compounds in the search for new medical agents, see: Shaikh et al. (2011).
We recently have been involved in the synthesis and characterization of natural products from this family of compounds in the search for new medical agents (Shaikh et al., 2011). The title compound is an intermediate step in the synthesis of 5,7 dimethoxy-3-benzyl-4-chroman-none.
There a few analogous structures of chroman alcohols bearing a benzyl ring found in the literature. The two closest have the 5,7 dimethoxy moieties, where one is a biphenyl derivative with an alkylated ketone at the 4 position (Koch et al.,1994) the other has a phenyl group at the 2 position but no alcohol functionality (Porter et al., 1985). Here we report the first example where a chroman-ol benzyl derivative ( Fig. 1) that demonstrates hydrogen bonding in the solid state. This intermolecular hydrogen bond O2-H-O1 (2.8366 Å) holds the structure in two parallel plains (Fig. 2). The intermolecular distances between the ring centroids are all greater than 6 Å suggesting that there is no π -stacking.

Experimental
To a solution of 5,7-dimethoxy-3-(benzyl)-4-chromanone (1.0 g, 3.3 mmol) in anhydrous MeOH (15 ml), NaBH 4 (0.38 g, 10.0 mmol) was added portionwise at a temperature of 0 °C under a nitrogen atmosphere. The mixture was then allowed to reach room temperature and stirred for 1 h. The reaction mixture was quenched with water and extracted with ethyl acetate (3 x 30 ml). The organic layer was washed with brine, dried over magnesium sulfate, and concentrated under reduced pressure to produce a viscous oil mixture. The residue obtained after evaporation of the solvent was chromatographed over a silica gel column using mixture of ethyl acetate/hexane (30:70) as eluent product to yield of 88% (0.88 g). Off-white solid; m.p.
118-121 °C. The title compound was recrystalized from a solution of ethyl acetate/hexane (30:70) at room temperature. Single-crystal X-ray diffraction data were collected on a Bruker KAPPA APEX II DUO diffractometer using graphite-monochromated Mo-Ka radiation (c = 0.71073 Å). Data collection was carried out at 100 (2) K. Temperature was controlled by an Oxford Cryostream cooling system (Oxford Cryostat). Cell refinement and data reduction were performed using the program SAINT (Bruker, 2006). The data were scaled and empirical absorption corrections were performed using SADABS (Sheldrick, 1997). The structure was solved by direct methods using SHELXS97 (Sheldrick, 2008) and refined by full-matrix least-squares methods based on F 2 using SHELXL97 (Sheldrick, 2008) and using the graphics interface program X-SEED (Barbour, 2001). All non-hydrogen atoms were refined anisotropically. All hydrogen atoms, except the hydroxyl hydrogen, were positioned geometrically with C-H distances ranging from 0.95 Å to 1.00 Å and refined as riding on their parent atoms, with U iso (H) = 1.2 -1.5 U eq (C).