Methyl 2-O-β-D-glucopyranosyl-α-L-rhamnopyranoside

The overall conformation of the title compound, C₁₃H₂₄O₁₀, is described by the glycosidic torsion angles φ_H (H1_g—C1_g—O2_r—C2_r) and ψ_H (C1_g—O2_r—C2_r—H2_r), which have values of 13.6 and 16.1°, respectively. The former is significantly different from the value predicted by consideration of the exo-anomeric effect (φ_H ∼ 60°) and from that in solution (φ_H ∼ 50°), as determined previously by NMR spectroscopy. An intramolecular O3_r—H...O2_g hydrogen bond may help to stabilize the conformation in the solid state. The orientation of the hydroxy­methyl group of the glucose residue is gauche–gauche, with a torsion angle ω (O5_g—C5_g—C6_g—O6_g) of −70.4 (4)°. Both pyranose rings are in their expected chair conformations, i.e. ⁴C₁ for D-glucose and ¹C₄ for L-rhamnose.

S1. Comment

Oligo- and polysaccharides have many important roles in biological systems (Varki, 1993). Many of their effects are mediated by interaction with other biomolecules, in particular, proteins such as antibodies and lectins. An understanding of these interactions on a molecular level requires a detailed knowledge of the conformational preferences of carbohydrates, as well as those of proteins. At present, most of our knowledge of carbohydrate conformation is derived from NMR spectroscopy, but the information is scarce and often difficult to interpret. It is therefore important to obtain further data using other experimental techniques.

Whilst methyl 2-O-β-D-glucopyranosyl-α-L-rhamnopyranoside, (I), does not occur naturally, there are several bacterial polysaccharides and saponins that contain a 2-O-β-D-glucopyranosyl-α-L-rhamnopyranosyl fragment (Doubet & Albersheim, 1992), and which are likely to display conformational similarities with (I). \sch

The solution conformation of (I) has been determined from ¹H-¹H NOE (nuclear Overhauser effect) and ³J_C,H measurements, and compared with the results of in vacuo molecular modelling (Mamyan et al., 1990). The computed lowest-energy conformation differs from the crystal structure and has ϕ_H ~50° and ψ_H ~20°. Thus, the difference in ϕ_H is more than 30°, despite the fact that this torsion angle is considered to be more restricted than ψ_H because the exo-anomeric effect stabilizes the conformation with ϕ_H at around 60° (Thøgersen et al., 1982). A comparison with the reported ³J_C,H and ¹H-¹H NOE values shows that, in solution, (I) is much more similar to the calculated structure than the conformation found here for the solid state.

The calculated Cremer & Pople (1975) puckering parameters show that both pyranose rings in (I) are in the expected chair conformations, ¹C₄ for the rhamnose ring [Q = 0.598 (4) Å, θ = 175.7 (4)° and ϕ = 75 (4)°] and ⁴C₁ for the glucose ring [Q = 0.615 (4) Å, θ = 6.3 (4)° and ϕ = 98 (3)°].

Four distinct hydrogen-bond systems can be deduced from the structural model. The donor···acceptor sequence is, for the first infinite chain along the b axis, composed of: O3_r⁽ⁱ⁾-H···O2_g⁽ⁱ⁾-H···O3_r⁽ⁱⁱ⁾-H···O2_g⁽ⁱⁱ⁾-H···O3_r⁽ⁱⁱⁱ⁾-H··· etc. along the b axis, where the subscripts r and g denote the rhamnose and glucose residues, respectively [symmetry codes: (i) x, y, z; (ii) -x, 1/2 + y, 1 - z; (iii) x, 1 + y, z]. This first hydrogen-bonded chain (Fig. 2) contains an intramolecular hydrogen bond, (O3_r—H···O2_g); otherwise, all the hydrogen bonds are intermolecular. Secondly, there is a ladder-like structure of hydrogen bonds along the b direction made up of two distinct bonds, O6_g⁽ⁱ⁾-H···O5_r^(iv) and O6_g^(iv)-H···O5_r⁽ⁱⁱⁱ⁾ etc. [symmetry code: (iv) 1 - x, 1/2 + y, 2 - z]. The third hydrogen-bonded chain is a three-edged graph connected to atom O3_r of the first chain and is composed of O3_g⁽ⁱ⁾-H···O4_r^(v)-H···O4_g^(v)-H···O3_r⁽ⁱ⁾-H [symmetry code: (v) 1 - x, y - 1, 1 - z]. These hydrogen bonds link molecules of (I) to form sheets in the ab plane. These sheets are further linked to each other through the fourth hydrogen bond connection, O6_g⁽ⁱ⁾-H···O5_r^(iv)-H. Please check symmetry codes have been extracted correctly.

S2. Experimental

The synthesis of (I) has been described by Jansson et al. (1990). Crystals of (I) were obtained by slow evaporation at ambient temperature from a solution of the disaccharide in methanol-water.

S3. Refinement

Please check added text below. The absolute configuration of the molecule cannot be deduced from the diffraction data collected in this experiment. It can, however, be assigned from the known absolute configuration of the reactants. The O—H distances were set at 0.82 Å, while the C—H distances were set at 0.98, 0.97 and 0.96 Å for CH, CH₂ and CH₃, respectively. One of the H atoms (HO3_r) was refined freely, with an O3_r—HO3_r distance restraint of 0.82 Å. For methyl and hydroxyl H atoms, U_iso(H) = 1.5U_eq(C, O), while for other H atoms, U_iso(H) = 1.2U_eq(C).

Computing details

Data collection: EXPOSE in IPDS (Stoe & Cie, 1997); cell refinement: CELL in IPDS; data reduction: INTEGRATE in IPDS; program(s) used to solve structure: SHELXS86 (Sheldrick, 1990); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: DIAMOND (Bergerhoff, 1996) and SCHAKAL (Keller, 1992); software used to prepare material for publication: SHELXL97 and PLATON98 (Spek, 1998).

Figures

	Fig. 1. A view of the molecular structure of (I) showing the atom-labelling scheme and 50% probability displacement ellipsoids. H atoms are drawn as small spheres of arbitrary radii.
	Fig. 2. A stereoview of the infinite hydrogen-bond chain along the b axis, O3r^(i)-H···O2g^(i)-H···O3r^(ii)-H···O2g^(ii)-H···O3r^(iii)-H [symmetry codes: (i) x, y, z; (ii) -x, 1/2 + y, 1 - z; (iii) x, 1 + y, z]. Please check symmetry codes have been extracted correctly.

Methyl 2-O-β-D-glucopyranosyl-α-L-rhamnopyranoside

Crystal data

C13H24O10	F(000) = 364
Mr = 340.32	Dx = 1.502 Mg m^−3
Monoclinic, P21	Mo Kα radiation, λ = 0.71073 Å
a = 7.180 (4) Å	Cell parameters from 628 reflections
b = 8.430 (5) Å	θ = 2.5–26.0°
c = 12.688 (10) Å	µ = 0.13 mm^−1
β = 101.46 (8)°	T = 293 K
V = 752.6 (8) Å^3	Thin prismatic flake, colourless
Z = 2	0.12 × 0.08 × 0.03 mm

Data collection

Stoe IPDS image-plate diffractometer	1542 independent reflections
Radiation source: fine-focus sealed tube	1251 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.071
Detector resolution: 6.0 pixels mm^-1	θmax = 25.8°, θmin = 2.9°
area detector scans	h = −8→8
Absorption correction: numerical (X-RED; Stoe & Cie, 1997)	k = −10→10
Tmin = 0.97, Tmax = 0.99	l = −15→15
11346 measured reflections

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: mixed
R[F^2 > 2σ(F^2)] = 0.037	H atoms treated by a mixture of independent and constrained refinement
wR(F^2) = 0.087	w = 1/[σ^2(Fo^2) + (0.05P)^2] where P = (Fo^2 + 2Fc^2)/3
S = 1.07	(Δ/σ)max = 0.001
1542 reflections	Δρmax = 0.20 e Å^−3
219 parameters	Δρmin = −0.19 e Å^−3
4 restraints	Extinction correction: SHELXL97 (Sheldrick, 1997), Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.022 (5)

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 F² against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F², conventional R-factors R are based on F, with F set to zero for negative F². The threshold expression of F² > σ(F²) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F² are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger.

Two separate data sets were collected and merged according to the Laue symmetry before refinement; a total of 1275 Friedel equivalents were present in the data before averaging. All non-H atoms were refined with anisotropic displacement parameters subject to rigid-bond restraints (Rollett, 1970; Sheldrick, 1997). Methyl and hydroxyl H atoms were located from difference Fourier syntheses, while others were placed geometrically. The H atoms on the methyl C atoms were refined as rigid groups rotating around the C—X bond, where X is the non-H atom connected to the C atom. Similarly, the hydroxyl H atom was allowed to rotate about the local O—X vector.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
C1r	0.3258 (5)	0.6045 (4)	0.8460 (3)	0.0161 (7)
H1r	0.4374	0.6457	0.8958	0.019*
C2r	0.3098 (5)	0.6885 (4)	0.7392 (3)	0.0139 (7)
H2r	0.4189	0.6602	0.7073	0.017*
O2r	0.3103 (3)	0.8577 (3)	0.75763 (19)	0.0185 (6)
C3r	0.1239 (4)	0.6417 (4)	0.6609 (3)	0.0159 (7)
H3r	0.1268	0.5276	0.6464	0.019*
O3r	0.1048 (3)	0.7262 (2)	0.5610 (2)	0.0170 (5)
HO3r	0.103 (6)	0.8220 (9)	0.572 (3)	0.026*
C4r	−0.0415 (5)	0.6765 (4)	0.7169 (3)	0.0158 (8)
H4r	−0.0378	0.7896	0.7351	0.019*
O4r	−0.2220 (3)	0.6438 (3)	0.64683 (19)	0.0178 (6)
HO4r	−0.2367	0.5476	0.6402	0.023*
C5r	−0.0151 (5)	0.5823 (4)	0.8211 (3)	0.0164 (8)
H5r	−0.0080	0.4687	0.8059	0.020*
O5r	0.1595 (3)	0.6339 (3)	0.89106 (18)	0.0164 (5)
Om	0.3539 (3)	0.4447 (3)	0.8294 (2)	0.0173 (5)
Cm	0.3868 (6)	0.3518 (5)	0.9270 (3)	0.0231 (8)
HmA	0.4201	0.2453	0.9112	0.035*
HmB	0.2736	0.3502	0.9564	0.035*
HmC	0.4888	0.3980	0.9782	0.035*
C6r	−0.1757 (5)	0.6135 (5)	0.8816 (3)	0.0183 (7)
H7rA	−0.1430	0.5687	0.9525	0.027*
H7rB	−0.2908	0.5655	0.8435	0.027*
H7rC	−0.1942	0.7258	0.8870	0.027*
C1g	0.4264 (5)	0.9485 (4)	0.7032 (3)	0.0167 (8)
H1g	0.4666	0.8851	0.6469	0.020*
C2g	0.3191 (5)	1.0972 (4)	0.6546 (3)	0.0153 (7)
H2g	0.2876	1.1637	0.7120	0.018*
O2g	0.1459 (3)	1.0434 (3)	0.5841 (2)	0.0198 (6)
HO2g	0.1256	1.0976	0.5293	0.030*
C3g	0.4465 (5)	1.1878 (4)	0.5940 (3)	0.0151 (7)
H3g	0.4818	1.1176	0.5396	0.018*
O3g	0.3557 (4)	1.3248 (3)	0.5418 (2)	0.0194 (6)
HO3g	0.3159	1.3052	0.4780	0.029*
C4g	0.6290 (5)	1.2355 (4)	0.6750 (3)	0.0158 (7)
H4g	0.5930	1.3064	0.7288	0.019*
O4g	0.7620 (3)	1.3174 (3)	0.6235 (2)	0.0181 (6)
HO4g	0.7542	1.2829	0.5623	0.027*
C5g	0.7211 (5)	1.0859 (4)	0.7327 (3)	0.0176 (8)
H5g	0.7628	1.0173	0.6795	0.021*
O5g	0.5886 (3)	0.9994 (3)	0.7813 (2)	0.0184 (6)
C6g	0.8932 (5)	1.1232 (5)	0.8216 (3)	0.0195 (8)
H6gA	0.9362	1.0265	0.8602	0.023*
H6gB	0.9959	1.1624	0.7893	0.023*
O6g	0.8504 (4)	1.2380 (3)	0.8954 (2)	0.0218 (6)
HO6g	0.8449	1.1946	0.9525	0.033*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
C1r	0.0090 (16)	0.0190 (18)	0.0213 (18)	−0.0040 (14)	0.0057 (14)	−0.0014 (16)
C2r	0.0101 (16)	0.0114 (18)	0.0199 (18)	0.0018 (13)	0.0021 (14)	0.0002 (14)
O2r	0.0149 (13)	0.0192 (13)	0.0221 (13)	−0.0026 (10)	0.0051 (11)	−0.0004 (11)
C3r	0.0108 (17)	0.0189 (18)	0.0180 (17)	−0.0011 (15)	0.0030 (15)	−0.0022 (15)
O3r	0.0143 (12)	0.0168 (13)	0.0205 (12)	0.0002 (11)	0.0048 (10)	0.0008 (11)
C4r	0.0116 (17)	0.0144 (17)	0.0209 (18)	0.0012 (13)	0.0023 (15)	−0.0002 (14)
O4r	0.0125 (12)	0.0181 (13)	0.0221 (13)	−0.0013 (10)	0.0016 (11)	−0.0012 (11)
C5r	0.0100 (16)	0.0201 (19)	0.0180 (18)	−0.0015 (13)	0.0001 (15)	−0.0020 (15)
O5r	0.0115 (12)	0.0184 (13)	0.0196 (12)	0.0014 (10)	0.0037 (10)	−0.0005 (11)
Om	0.0142 (12)	0.0159 (12)	0.0224 (13)	0.0012 (10)	0.0049 (10)	0.0006 (11)
Cm	0.025 (2)	0.021 (2)	0.0232 (19)	0.0020 (17)	0.0050 (17)	0.0029 (17)
C6r	0.0181 (17)	0.0182 (18)	0.0197 (17)	0.0021 (16)	0.0065 (15)	0.0028 (16)
C1g	0.0126 (17)	0.0169 (19)	0.0199 (18)	−0.0042 (15)	0.0015 (14)	0.0006 (16)
C2g	0.0105 (16)	0.0137 (18)	0.0209 (17)	−0.0037 (14)	0.0015 (14)	−0.0011 (15)
O2g	0.0137 (12)	0.0179 (14)	0.0257 (14)	−0.0019 (11)	−0.0013 (11)	0.0028 (11)
C3g	0.0110 (16)	0.0141 (18)	0.0204 (18)	−0.0018 (13)	0.0035 (15)	−0.0001 (14)
O3g	0.0174 (13)	0.0171 (13)	0.0227 (13)	0.0007 (11)	0.0014 (11)	0.0013 (11)
C4g	0.0129 (17)	0.0173 (18)	0.0180 (17)	−0.0028 (15)	0.0053 (15)	0.0004 (16)
O4g	0.0133 (12)	0.0196 (14)	0.0221 (13)	−0.0018 (10)	0.0055 (11)	0.0018 (11)
C5g	0.0140 (17)	0.018 (2)	0.0210 (18)	−0.0013 (14)	0.0030 (15)	0.0027 (16)
O5g	0.0124 (11)	0.0195 (13)	0.0229 (13)	−0.0006 (10)	0.0023 (10)	0.0003 (11)
C6g	0.0200 (18)	0.0151 (18)	0.0235 (19)	−0.0014 (16)	0.0044 (16)	−0.0006 (16)
O6g	0.0215 (13)	0.0203 (14)	0.0227 (13)	−0.0011 (11)	0.0023 (12)	0.0026 (12)

Geometric parameters (Å, º)

C1r—Om	1.385 (5)	C6r—H7rB	0.9600
C1r—O5r	1.443 (4)	C6r—H7rC	0.9600
C1r—C2r	1.514 (5)	C1g—O5g	1.436 (4)
C1r—H1r	0.9800	C1g—C2g	1.535 (5)
C2r—O2r	1.445 (4)	C1g—H1g	0.9800
C2r—C3r	1.548 (5)	C2g—O2g	1.453 (4)
C2r—H2r	0.9800	C2g—C3g	1.513 (5)
O2r—C1g	1.409 (4)	C2g—H2g	0.9800
C3r—O3r	1.437 (4)	O2g—HO2g	0.8200
C3r—C4r	1.528 (4)	C3g—O3g	1.423 (4)
C3r—H3r	0.9800	C3g—C4g	1.549 (5)
O3r—HO3r	0.820 (12)	C3g—H3g	0.9800
C4r—O4r	1.445 (4)	O3g—HO3g	0.8200
C4r—C5r	1.522 (5)	C4g—O4g	1.436 (4)
C4r—H4r	0.9800	C4g—C5g	1.540 (5)
O4r—HO4r	0.8200	C4g—H4g	0.9800
C5r—O5r	1.452 (4)	O4g—HO4g	0.8200
C5r—C6r	1.530 (5)	C5g—O5g	1.432 (4)
C5r—H5r	0.9800	C5g—C6g	1.531 (5)
Om—Cm	1.443 (4)	C5g—H5g	0.9800
Cm—HmA	0.9600	C6g—O6g	1.421 (4)
Cm—HmB	0.9600	C6g—H6gA	0.9700
Cm—HmC	0.9600	C6g—H6gB	0.9700
C6r—H7rA	0.9600	O6g—HO6g	0.8200
Om—C1r—O5r	112.6 (3)	C5r—C6r—H7rC	109.5
Om—C1r—C2r	107.9 (3)	H7rA—C6r—H7rC	109.5
O5r—C1r—C2r	110.6 (3)	H7rB—C6r—H7rC	109.5
Om—C1r—H1r	108.6	O2r—C1g—O5g	107.5 (3)
O5r—C1r—H1r	108.6	O2r—C1g—C2g	110.0 (3)
C2r—C1r—H1r	108.6	O5g—C1g—C2g	107.8 (3)
O2r—C2r—C1r	108.6 (3)	O2r—C1g—H1g	110.5
O2r—C2r—C3r	109.3 (3)	O5g—C1g—H1g	110.5
C1r—C2r—C3r	110.9 (3)	C2g—C1g—H1g	110.5
O2r—C2r—H2r	109.3	O2g—C2g—C3g	112.0 (3)
C1r—C2r—H2r	109.3	O2g—C2g—C1g	107.0 (3)
C3r—C2r—H2r	109.3	C3g—C2g—C1g	108.1 (3)
C1g—O2r—C2r	116.0 (3)	O2g—C2g—H2g	109.9
O3r—C3r—C4r	111.5 (3)	C3g—C2g—H2g	109.9
O3r—C3r—C2r	111.0 (3)	C1g—C2g—H2g	109.9
C4r—C3r—C2r	107.7 (3)	C2g—O2g—HO2g	109.5
O3r—C3r—H3r	108.9	O3g—C3g—C2g	112.2 (3)
C4r—C3r—H3r	108.9	O3g—C3g—C4g	110.3 (3)
C2r—C3r—H3r	108.9	C2g—C3g—C4g	108.1 (3)
C3r—O3r—HO3r	110 (3)	O3g—C3g—H3g	108.7
O4r—C4r—C5r	112.1 (3)	C2g—C3g—H3g	108.7
O4r—C4r—C3r	111.3 (3)	C4g—C3g—H3g	108.7
C5r—C4r—C3r	109.2 (3)	C3g—O3g—HO3g	109.5
O4r—C4r—H4r	108.0	O4g—C4g—C5g	110.4 (3)
C5r—C4r—H4r	108.0	O4g—C4g—C3g	112.0 (3)
C3r—C4r—H4r	108.0	C5g—C4g—C3g	109.2 (3)
C4r—O4r—HO4r	109.5	O4g—C4g—H4g	108.4
O5r—C5r—C4r	108.5 (3)	C5g—C4g—H4g	108.4
O5r—C5r—C6r	106.7 (3)	C3g—C4g—H4g	108.4
C4r—C5r—C6r	111.7 (3)	C4g—O4g—HO4g	109.5
O5r—C5r—H5r	109.9	O5g—C5g—C6g	107.2 (3)
C4r—C5r—H5r	109.9	O5g—C5g—C4g	111.3 (3)
C6r—C5r—H5r	109.9	C6g—C5g—C4g	112.9 (3)
C1r—O5r—C5r	112.9 (3)	O5g—C5g—H5g	108.4
C1r—Om—Cm	113.7 (3)	C6g—C5g—H5g	108.4
Om—Cm—HmA	109.5	C4g—C5g—H5g	108.4
Om—Cm—HmB	109.5	C5g—O5g—C1g	111.8 (3)
HmA—Cm—HmB	109.5	O6g—C6g—C5g	112.1 (3)
Om—Cm—HmC	109.5	O6g—C6g—H6gA	109.2
HmA—Cm—HmC	109.5	C5g—C6g—H6gA	109.2
HmB—Cm—HmC	109.5	O6g—C6g—H6gB	109.2
C5r—C6r—H7rA	109.5	C5g—C6g—H6gB	109.2
C5r—C6r—H7rB	109.5	H6gA—C6g—H6gB	107.9
H7rA—C6r—H7rB	109.5	C6g—O6g—HO6g	109.5
Om—C1r—C2r—O2r	−171.2 (2)	C2r—O2r—C1g—C2g	135.9 (3)
O5r—C1r—C2r—O2r	65.3 (3)	O2r—C1g—C2g—O2g	−57.4 (3)
Om—C1r—C2r—C3r	68.7 (3)	O5g—C1g—C2g—O2g	−174.4 (2)
O5r—C1r—C2r—C3r	−54.8 (4)	O2r—C1g—C2g—C3g	−178.1 (3)
C1r—C2r—O2r—C1g	135.4 (3)	O5g—C1g—C2g—C3g	64.9 (3)
C3r—C2r—O2r—C1g	−103.5 (3)	O2g—C2g—C3g—O3g	59.8 (4)
O2r—C2r—C3r—O3r	57.9 (3)	C1g—C2g—C3g—O3g	177.4 (3)
C1r—C2r—C3r—O3r	177.7 (3)	O2g—C2g—C3g—C4g	−178.3 (3)
O2r—C2r—C3r—C4r	−64.4 (3)	C1g—C2g—C3g—C4g	−60.8 (3)
C1r—C2r—C3r—C4r	55.3 (4)	O3g—C3g—C4g—O4g	−59.1 (3)
O3r—C3r—C4r—O4r	54.9 (4)	C2g—C3g—C4g—O4g	177.8 (3)
C2r—C3r—C4r—O4r	177.0 (3)	O3g—C3g—C4g—C5g	178.3 (3)
O3r—C3r—C4r—C5r	179.2 (3)	C2g—C3g—C4g—C5g	55.3 (3)
C2r—C3r—C4r—C5r	−58.8 (4)	O4g—C4g—C5g—O5g	−177.9 (3)
O4r—C4r—C5r—O5r	−174.2 (3)	C3g—C4g—C5g—O5g	−54.3 (3)
C3r—C4r—C5r—O5r	62.1 (3)	O4g—C4g—C5g—C6g	61.5 (4)
O4r—C4r—C5r—C6r	−56.8 (4)	C3g—C4g—C5g—C6g	−174.9 (3)
C3r—C4r—C5r—C6r	179.4 (3)	C6g—C5g—O5g—C1g	−176.0 (3)
Om—C1r—O5r—C5r	−62.0 (4)	C4g—C5g—O5g—C1g	60.1 (3)
C2r—C1r—O5r—C5r	58.8 (4)	O2r—C1g—O5g—C5g	176.9 (3)
C4r—C5r—O5r—C1r	−62.2 (4)	C2g—C1g—O5g—C5g	−64.6 (3)
C6r—C5r—O5r—C1r	177.3 (3)	O5g—C5g—C6g—O6g	−70.4 (4)
O5r—C1r—Om—Cm	−62.4 (4)	C4g—C5g—C6g—O6g	52.5 (4)
C2r—C1r—Om—Cm	175.3 (3)	C2r—O2r—C1g—H1g	13.6
C2r—O2r—C1g—O5g	−107.0 (3)	H2r—C2r—O2r—C1g	16.1

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O3r—HO3r···O2g	0.82 (1)	1.89 (1)	2.700 (4)	168 (4)
O4r—HO4r···O4g^i	0.82	1.952	2.768 (4)	173
O2g—HO2g···O3r^ii	0.82	2.115	2.772 (4)	137
O3g—HO3g···O4r^ii	0.82	2.10	2.840 (4)	151
O4g—HO4g···O3r^iii	0.82	2.081	2.806 (4)	147
O6g—HO6g···O5r^iv	0.82	2.056	2.862 (4)	168

Symmetry codes: (i) x−1, y−1, z; (ii) −x, y+1/2, −z+1; (iii) −x+1, y+1/2, −z+1; (iv) −x+1, y+1/2, −z+2.