4-Hydroxymethyl-1-( 2 , 3 , 4 , 6-tetra-O-acetyl-bD-glucopyranosyl )-1 , 2 , 3-triazole

# 2006 International Union of Crystallography All rights reserved The structure of the title compound, C17H23N3O10, (2), has been determined as part of our investigation into the synthetic utility of the glucosyl triazole unit in carbohydrate chemistry. Compound (2) was synthesized by the 1,3-dipolar cycloaddition reaction of propargyl alcohol with 2,3,4,6-tetra-Oacetyl-d-glucopyranosyl azide under conditions which afforded (2) exclusively with complete retention of anomeric stereochemistry. The six-membered carbohydrate ring adopts a chair conformation. The non-H substituents are located in equatorial positions.

The structure of the title compound, C 17 H 23 N 3 O 10 , (2), has been determined as part of our investigation into the synthetic utility of the glucosyl triazole unit in carbohydrate chemistry. Compound (2) was synthesized by the 1,3-dipolar cycloaddition reaction of propargyl alcohol with 2,3,4,6-tetra-Oacetyl--d-glucopyranosyl azide under conditions which afforded (2) exclusively with complete retention of anomeric stereochemistry. The six-membered carbohydrate ring adopts a chair conformation. The non-H substituents are located in equatorial positions.

Comment
As part of our interest in the synthesis of triazole-linked glycoconjugates as carbonic anhydrase inhibitors, the glycosyl triazole title compound was synthesized and subsequently interrogated under conditions typically encountered in carbohydrate chemistry reaction sequences -including alcohol group protection/deprotection, nucleophilic displacement and O-glycosylation. The triazole integrity was retained in all cases studied (Wilkinson et al., 2006). The title compound, (2), was prepared by the copper-mediated 1,3dipolar cycloaddition reaction (1,3-DCR) of propargyl alcohol with the azide partner 2,3,4,6-tetra-O-acetyl--d-glucopyranosyl azide, (1), in aqueous alcohol. The addition of Cu I ions to this classical 1,3-DCR has proved to be a major breakthrough in triazole chemistry as it affords exclusively a 1,4disubstituted triazole as product (Rostovtsev et al., 2002;Tornøe et al., 2002). Prior to this discovery the reaction of the 1,3-DCR of acetylene and azide substrates almost always gave a mixture of 1,4 and 1,5 regioisomers as products (Gothelf & Jorgensen, 1998). This 1,4-substitution pattern of (2) and the configuration at C1 are confirmed here by X-ray crystallography.
In the structure of (2) (Fig. 1), the bond lengths and angles (Table 1) are in accord with expected values (Temelkoff et al., 2004;Wilkinson et al., 2005). The six-membered carbohydrate ring adopts a chair conformation. The non-H substituents are located in equatorial positions. The carbonyl group of the acetate groups on C2, C3 and C4, the methyl ester group on C5, and the N3 group of the triazole on C1 adopt cis conformations with respect to the axial H atoms (Wiberg & Laidig, 1987). The crystal structure is stabilized by a number of C-HÁ Á ÁO and C-HÁ Á ÁN interactions (Table 2) and a strong intermolecular O-HÁ Á ÁO hydrogen bond between the hydroxyl H atom on the triazole group and the carbonyl atom O62 (Table 2 and Fig. 2).
values were set at 1.2U eq of the parent atom. In the absence of significant anomalous scattering effects, Friedel pairs were merged. The absolute configuration was assigned on the basis of the known configuration of the starting material.
Data collection: MSC/AFC7 Diffractometer Control (Molecular Structure Corporation, 1999); cell refinement: MSC/AFC7 Diffractometer Control; data reduction: TEXSAN for Windows (Molecular Structure Corporation, 2001); program(s) used to solve structure: TEXSAN for Windows; program(s) used to refine structure: TEXSAN for Windows and SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 (Farrugia, 1997); software used to prepare material for publication: TEXSAN for Windows and PLATON (Spek, 2003). supporting information sup-1 Acta Cryst. (2006). E62, o5065-o5067 supporting information Acta Cryst. (2006). E62, o5065-o5067 [https://doi.org/10.1107/S1600536806040864] Geometry. Bond distances, angles etc. have been calculated using the rounded fractional coordinates. All su's are estimated from the variances of the (full) variance-covariance matrix. The cell e.s.d.'s are taken into account in the estimation of distances, angles and torsion angles 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.  (7) 148.00