4-Formyl­phenyl 2,3,4,6-tetra-O-acetyl-β-d-galactopyran­oside

Rusnah Syahila Duali Hussen; Thorsten Heidelberg; Nasrul Zamani Mohd Rodzi; Seik Weng Ng; Edward R T Tiekink

doi:10.1107/S1600536811008257

. 2011 Mar 9;67(Pt 4):o826. doi: 10.1107/S1600536811008257

4-Formylphenyl 2,3,4,6-tetra-O-acetyl-β-d-galactopyranoside

Rusnah Syahila Duali Hussen ^a, Thorsten Heidelberg ^a,^‡, Nasrul Zamani Mohd Rodzi ^a, Seik Weng Ng ^a, Edward R T Tiekink ^a,^*

PMCID: PMC3099913 PMID: 21754110

Abstract

The galactose ring in the title compound, C₂₁H₂₄O₁₁, has a chair conformation with the substituted benzene ring occupying an equatorial position. The crystal packing features C—H⋯O interactions that lead to the formation of supramolecular layers in the ab plane.

Related literature

For the synthesis, see: Benassi et al. (2007 ▶); Patil et al. (2008 ▶). For the biological activity of related structures, see: Zheng et al. (2010 ▶). For the structure of the isomeric allopyranoside and glucopyranoside derivatives, see: Ye et al. (2009 ▶); Heidelberg et al. (2011 ▶). For conformational analysis, see: Cremer & Pople (1975 ▶).

Experimental

Crystal data

C₂₁H₂₄O₁₁
M _r = 452.40
Monoclinic,
a = 11.8358 (4) Å
b = 5.6664 (2) Å
c = 17.5079 (6) Å
β = 109.616 (4)°
V = 1106.05 (7) Å³
Z = 2
Mo Kα radiation
μ = 0.11 mm⁻¹
T = 100 K
0.25 × 0.20 × 0.05 mm

Data collection

Agilent Supernova Dual diffractometer with an Atlas detector
Absorption correction: multi-scan (CrysAlis PRO; Agilent, 2010 ▶) T _min = 0.596, T _max = 1.000
10396 measured reflections
2768 independent reflections
2535 reflections with I > 2σ(I)
R _int = 0.051

Refinement

R[F ² > 2σ(F ²)] = 0.035
wR(F ²) = 0.086
S = 1.05
2768 reflections
293 parameters
1 restraint
H-atom parameters constrained
Δρ_max = 0.21 e Å⁻³
Δρ_min = −0.21 e Å⁻³

Data collection: CrysAlis PRO (Agilent, 2010 ▶); cell refinement: CrysAlis PRO; data reduction: CrysAlis PRO; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: ORTEP-3 (Farrugia, 1997 ▶) and DIAMOND (Brandenburg, 2006 ▶); software used to prepare material for publication: publCIF (Westrip, 2010 ▶).

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536811008257/ez2236sup1.cif

e-67-0o826-sup1.cif^{(22.6KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536811008257/ez2236Isup2.hkl

e-67-0o826-Isup2.hkl^{(135.9KB, 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
C3—H3⋯O9ⁱ	1.00	2.39	3.199 (3)	137
C5—H5⋯O9ⁱ	1.00	2.45	3.268 (3)	139
C10—H10b⋯O3ⁱⁱ	0.98	2.46	3.307 (3)	145
C12—H12b⋯O5ⁱⁱⁱ	0.98	2.57	3.548 (3)	172
C14—H14c⋯O11^iv	0.98	2.50	3.415 (4)	155

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Symmetry codes: (i) Inline graphic ; (ii) ; (iii) ; (iv) .

Acknowledgments

This study was supported by the University of Malaya under research grant FS306/2007 C. The authors are also grateful to the University of Malaya for support of the crystallographic facility.

supplementary crystallographic information

Comment

The title compound, 4-formyl-phenyl 2,3,4,6-tetra-O-acetyl-β-D-galactopyranoside, a known species (Benassi et al., 2007; Patil et al., 2008), was prepared as a precursor for the synthesis of galactosylated resveratrol, an anti-oxidizing agent with possible pharmaceutical potential (Zheng et al., 2010).

The structure determination, Fig. 1, confirms the relative stereochemistry. The absolute structure, while not determined experimentally, is based on that of the acetobromogalactose reagent, i.e. R, S, S, R and S for C1–C5, respectively. The galactose ring has a chair conformation as seen in the puckering parameters (Cremer & Pople, 1975): puckering amplitude (Q) = 0.579 (2) Å, θ = 166.9 (2) °, and φ = 187.6 (10) °. Around the ring, the substituents at the C1, C4 and C5 atoms are equatorial, while at C2 the substituent is axial and that at the C3 atom is biaxial.

The crystal packing is dominated by C–H···O interactions, Table 1, involving all carbonyl atoms, except the O7 atom, as acceptors and either methine- or methyl-H as the donors. These lead to the formation of supramolecular layers that stack along the c axis, Fig. 2.

The present report complements the structures reported recently for the isomeric allopyranoside (Ye et al., 2009) and glucopyranoside (Heidelberg et al., 2011) derivatives.

Experimental

2,3,4,6-Tetra-O-acetyl-α-D-galactopyranosyl bromide (2.0 g) and 4-hydroxybenzaldehyde (1.0 g) were dissolved in chloroform (10 ml) and the mixture was treated with an aqueous solution (5 ml) of sodium carbonate (0.9 g) and tetrabutylammonium bromide (0.3 g). The mixture was heated to reflux under vigorous stirring overnight, after which ethyl acetate was added and the organic layer was washed three times with sodium hydroxide solution (1 N) to remove remaining phenols. After drying the solution over magnesium sulfate and evaporation of the solvent, the target product (1.4 g, 60%) was obtained by crystallization from 2-propanol/hexane (2:1).

¹H-NMR (400 MHz, CDCl₃): δ 9.93 (s; CHO), 7.85 & 7.11 (AB syst; aromatic 4 H), 5.52 (dd; H2), 5.48 (bd; H4), 5.17 (d; H1), 5.12 (dd; H3), 4.23 (dd; H6a), 4.19–4.10 (m, 2 H; H5, H6b), 2.19–2.02 (3 s, 12 H; Ac); ³J_4,5 = 10.0 Hz, ³J_5,6a = 5.0 Hz, ³J_{5,6 b} = 2.5 Hz, ²J₆ = 12.0 Hz.