3-Benzyl-5,7-dimeth­oxy­chroman-4-ol

Mahidansha M Shaikh; Glenn EM Maguire; Hendrik G Kruger; Karen du Toit

doi:10.1107/S1600536811002066

. 2011 Feb 23;67(Pt 3):o703. doi: 10.1107/S1600536811002066

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

Mahidansha M Shaikh ^a, Glenn EM Maguire ^b, Hendrik G Kruger ^b, Karen du Toit ^a,^*

PMCID: PMC3052041 PMID: 21522447

Abstract

In the crystal structure of the title compound, C₁₈H₂₀O₄, O—H⋯O 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 ▶).

Experimental

Crystal data

C₁₈H₂₀O₄
M _r = 300.34
Monoclinic,
a = 9.870 (5) Å
b = 11.211 (6) Å
c = 14.603 (7) Å
β = 107.072 (7)°
V = 1544.6 (13) Å³
Z = 4
Mo Kα radiation
μ = 0.09 mm⁻¹
T = 100 K
0.37 × 0.24 × 0.20 mm

Data collection

Bruker Kappa DUO APEXII diffractometer
12055 measured reflections
3882 independent reflections
3369 reflections with I > 2σ(I)
R _int = 0.021

Refinement

R[F ² > 2σ(F ²)] = 0.037
wR(F ²) = 0.100
S = 1.04
3882 reflections
203 parameters
1 restraint
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.38 e Å⁻³
Δρ_min = −0.21 e Å⁻³

Data collection: APEX2 (Bruker, 2006 ▶); cell refinement: SAINT (Bruker, 2006 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: OLEX2 (Dolomanov et al., 2009 ▶); software used to prepare material for publication: SHELXL97.

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536811002066/pb2047sup1.cif

e-67-0o703-sup1.cif^{(19.1KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536811002066/pb2047Isup2.hkl

e-67-0o703-Isup2.hkl^{(190.3KB, hkl)}

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Table 1. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O2—H2O⋯O1ⁱ	0.95 (1)	1.93 (1)	2.8366 (15)	158 (2)

Open in a new tab

Symmetry code: (i) Inline graphic .

Acknowledgments

The authors would like to thank Dr Hong Su (University of Capetown) for the data collection and structure refinement.

supplementary crystallographic information

Comment

Naturally ocurring homoisoflavanones that posses a 3-benzyl-substituted chroman ring system as a common framework have been isolated from a wide range of natural sources and exhibit a variety of biological activities (Zhang et al., 2008). 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), NaBH₄ (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.

¹H NMR (400 MHz, CDCl₃, δ, p.p.m.): 7.33–7.26 (m, 5H), 6.02 (d, J=2.20 Hz, 1H), 6.00 (d, J=2.20 Hz, 1H), 4.70 (d, J=2.40 Hz, 1H), 4.02 (dd, J=3.68, 6.20 Hz, 2H), 3.77 (s, 3H), 3.73 (s, 3H), 2.95 (dd, J=8.08, 8.12 Hz, 1H), 2.66 (dd, J=7.44, 7.44 Hz, 1H).

¹³C NMR (100 MHz, CDCl₃, δ, p.p.m.): 161.1, 159.2, 155.9, 139.6, 129.1, 128.4, 126.1, 106.7, 93.0, 91.4, 65.2, 59.6, 55.4, 55.3, 40.0, 32.9.

IR: 3501, 2946, 1592, 1453, 1304, 1200, 1052.

HRMS (EI): Calcd for C₁₈H₂₀O₄Na 323.1254, found 323.1271.