Isopropyl 2,3,4,6-tetra-O-acetyl-β-d-glucopyranoside

The title compound, C17H26O10, was formed by a Koenigs–Knorr reaction of 2,3,4,6-tetra-O-acetyl-α-d-glucopyranosyl bromide and propan-2-ol. The central ring adopts a chair conformation. The crystal does not contain any significant intermolecular interactions.

Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: BT6870).

Comment
In recent years the determination of alcohol metabolites gained importance for screening previous alcohol consumption (Joya et al., Helander et al., 2012). Beside ethanol several short-chain alkyl alcohols, e.g. i-propanol, are found in alcoholic beverages as a result of the fermentation process (Lachenmeier & Musshoff, 2004). The glucuronides of these so-called fusel alcohols are interesting markers for the consumption of alcohol (Sticht & Käferstein, 1999). Hence, the analysis of these glucuronic metabolites, including their synthesis and full characterization is mandatory.
The central ring has a chair conformation (Fig 1). The absolute configuration could not be defined confidently based on the single-crystal diffraction data. The isomeric purity of the title compound was confirmed by 1 H-NMR.

Refinement
All H-atoms were positioned geometrically and refined using a riding model with d(C-H) = 0.93 Å, U iso =1.2U eq (C) for aromatic 0.98 Å, U iso = 1.2U eq (C) for CH, 0.97 Å, U iso = 1.2U eq (C) for CH 2 , 0.96 Å, U iso = 1.5U eq (C) for CH 3 hydrogen atoms. In the absence of significant anomalous dispersion effects Friedel pairs were merged. The absolute configuration has not been determined by anomalous-dispersion effects in diffraction measurements of the crystal. The conformation has been assigned due to an unchanging chiral centre in the synthetic procedure.

Special details
Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes. 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 O1 0.5370 (