Methyl Β-allolactoside [methyl Β-d-galactopyranosyl-(1→6)- Β-d-glucopyran-oside] monohydrate

Article abstract of DOI:10.1107/S0108270109042310

Methyl Β-allolactoside [methyl Β-d-galactopyranosyl-(1→6)- Β-d-glucopyran-oside], (II), was crystallized from water as a monohydrate, C₁₃H₂₄O₁₁·H₂O. The ΒGalp and ΒGlcp residues in (II) assume distorted ⁴

Full text of DOI:10.1107/S0108270109042310

organic compounds
Acta Crystallographica Section C
Crystal Structure
Communications
Galp(1!6)-ꢀ-d-Galp-(1!6)-ꢀ-d-Glcp-(1!1)-Cer, isolated
from sea urchin eggs (Kubo et al., 1992), and in the soluble
protein bovine lactoferrin (Mir et al., 2009).
ISSN 0108-2701
Methyl b-allolactoside [methyl
b-D-galactopyranosyl-(1!6)-b-D-
glucopyranoside] monohydrate
Thomas E. Klepach,a Meredith Reed,b Bruce C. Noll,a
Allen G. Olivera and Anthony S. Seriannia*
aDepartment of Chemistry and Biochemistry, 251 Nieuwland Science Hall,
University of Notre Dame, Notre Dame, IN 46556-5670, USA, and bOmicron
Biochemicals Inc., South Bend, IN 46617, USA
Correspondence e-mail: anthony.s.serianni.1@nd.edu
Received 8 September 2009
Accepted 15 October 2009
Online 7 November 2009
Methyl ꢀ-allolactoside [methyl ꢀ-d-galactopyranosyl-(1!6)-
ꢀ-d-glucopyranoside], (II), was crystallized from water as a
monohydrate, C13H24O11ꢀH2O. The ꢀGalp and ꢀGlcp residues
4
in (II) assume distorted C1 chair conformations, with the
former more distorted than the latter. Linkage conformation
0
is characterized by ’0 (C2Gal—C1Gal—O1Gal—C6Glc),
(C1Gal—O1Gal—C6Glc—C5Glc) and ! (C4Glc—C5Glc—C6Glc
—
O1Gal) torsion angles of 172.9 (2), ꢁ117.9 (3) and ꢁ176.2 (2)ꢂ,
0
respectively. The and ! values differ significantly from
those found in the crystal structure of ꢀ-gentiobiose, (III)
[Rohrer et al. (1980). Acta Cryst. B36, 650–654]. Structural
comparisons of (II) with related disaccharides bound to a
mutant ꢀ-galactosidase reveal significant differences in
hydroxymethyl conformation and in the degree of ring
distortion of the ꢀGlcp residue. Structural comparisons of
(II) with a DFT-optimized structure, (IIC), suggest a link
between hydrogen bonding, pyranosyl ring deformation and
linkage conformation.
As structural information on the ꢀ-Gal-(1!6)-ꢀ-Glc link-
age in differing biological contexts grows, the geometry of the
isolated disaccharide, to which comparisons with more
complex structures can be made, increases in importance. We
report here the crystal structure of the methyl glycoside of (I),
namely methyl ꢀ-d-galactopyranosyl-(1!6)-ꢀ-d-glucopyran-
oside (methyl ꢀ-allolactoside) monohydrate, (II)ꢀH2O (Fig. 1).
Atom numbering is shown in the structure of (II), with primed
and unprimed numbers assigned to the ꢀGalp and ꢀGlcp
residue atoms, respectively. Structural parameters found for
(II) were compared with those observed in ꢀ-gentiobiose [ꢀ-d-
Comment
The disaccharide ꢀ-d-galactopyranosyl-(1!6)-d-glucopyran-
ose (allolactose), (I), is widely known as an inducer of the lac
operon. Allolactose serves as a negative allosteric effector of
the lac repressor (LacI) (Jacob & Monod, 1961; Burstein et al.,
1965; Jobe & Bourgeois, 1972; Yildirim & Mackey, 2003). In E.
coli, lactose [ꢀ-d-galactopyranosyl-(1!4)-d-glucopyranose] is
converted to (I) via transglycosylation catalyzed by ꢀ-
galactosidase (Jacob & Monod, 1961; Burstein et al., 1965;
Jobe & Bourgeois, 1972). The crystal structure of (I) has not
˚
`
been reported, but it appears in 1.5 A resolution cocrystals
glucopyranosyl-(1!6)-ꢀ-d-glucopyranose], (III) (Arene et al.,
with a mutant ꢀ-galactosidase (Juers et al., 2001). In addition
to its biological role as a free disaccharide, the ꢀ-d-Galp-
(1!6)-ꢀ-d-Glcp glycosidic linkage is observed in various
glycoconjugates, including a ceramide trisaccharide, ꢀ-d-
1979; Rohrer et al., 1980), which is the only structurally related
(1!6)-linked disaccharide whose crystal structure is known.
Comparisons were also made with structures of (Iꢀ) bound to
ꢀ-galactosidase (Juers et al., 2001), denoted (IG1), (IG2) and
Acta Cryst. (2009). C65, o601–o606
doi:10.1107/S0108270109042310
# 2009 International Union of Crystallography o601

organic compounds
(IG3), and with methyl ꢀ-d-galactopyranosyl-(1!4)-ꢀ-d-
glucopyranoside (methyl ꢀ-lactoside), (IV) (Stenutz et al.,
1999) (Table 1). The influence of crystal packing on structural
parameters was also investigated in an unconstrained in vacuo
density functional theory (DFT) geometry optimization using
GAUSSIAN03 (Frisch et al., 2004). The crystal structure of
(II) was used as the starting geometry and the calculation was
performed with the B3LYP functional (Becke, 1993), and the
6–31G* basis set (Hehre et al., 1972). Structural data for the
DFT structure, denoted (IIC), are shown in Table 1.
O40 bond conformation in (II) and (III) cannot be responsible
for this finding, since both bonds are in conformations in
which the C40 and O40 H atoms are eclipsed. Intermolecular
hydrogen bonding in the C40—O40 fragment of both (II) and
0
0
(III) is also identical. In contrast, rC4 ,O4 is considerably
shorter in (IIC) than in (II) and (III), presumably due, at least
partly, to relief of the eclipsing interaction in the calculated
structure [the equivalent C40 and O40 H atoms are approxi-
mately gauche in (IIC)]. These findings suggest that the rela-
tive lengths of axial and equatorial C—O bonds in saccharides
can be influenced significantly by crystal packing forces, and
that eclipsing interactions present in crystal structures caused
by the intermolecular hydrogen-bonding lattice may suppress
competing intramolecular forces that affect exocyclic C—O
bond lengths (e.g. bond orientation). The internal glycosidic
C—O—C bond angle in (II) and (III) appears slightly smaller
than observed in (IV), possibly due to the reduced steric
demands of the 1,6-linkage. This conclusion is supported by
glycosidic C—O—C bond angles involving the methyl agly-
cones in (II) and (III), which compare favorably to the
internal glycoside C—O—C angles in the same structures.
The ꢀGlcp and ꢀGalp rings of (II)–(IV) assume slightly
Data in Table 1 for (II)–(IV) yield the following average
˚
C—C bond lengths: C1—C2 = 1.522 (6) A; remaining endo-
˚
˚
cyclic C—C = 1.526 (7) A; C5—C6 = 1.511 (3) A. Exocyclic
C5—C6 bonds appear shorter than all endocyclic C—C bonds
(Pan et al., 2005), while C1—C2 bond lengths do not differ
statistically from the other endocyclic C—C bond lengths.
Average C—O bond lengths in (II)–(IV) are as follows:
˚
endocyclic C—O = 1.425 (9) A; anomeric C—O (exocyclic) =
˚
1.392 (6) A; exocyclic C—O = 1.426 (8) A; exocyclic C—O
˚
˚
involving the an0omeric oxygen = 1.434 (8) A. The equatorial
0
˚
C1—O1 and C1 —O1 bonds are shorter (by ꢃ0.03 A) than
the remaining exocyclic equatorial C—O bonds (Berman et
al., 1967), due to optimal anomeric effects (Lemieux, 1971) in
these structures; in (II), the C20—C10—O10—C6 and C2—
C1—O1—C7 torsion angles are 172.9 (2) and 177.4 (3)ꢂ,
respectively.
4
distorted C1 chair conformations based on Cremer–Pople
puckering parameters (Cremer & Pople, 1975; Table 2;
q3 >> q2). In (II), the ꢀGlcp ring is closer to an ideal 4C1 chair
form (ꢁ = 2.3ꢂ) than the ꢀGalp ring (ꢁ = 8.8ꢂ), whereas the
opposite is found for (IV). In (III), both rings have more
comparable ꢁ values and thus comparable degrees of distor-
tion. The direction of distortion, embodied in ’, is context
dependent and can be easily visualized using the projection
convention of Jeffrey & Yates (1979) (Fig. 2). Overall, global
ring shapes for the ꢀGalp ring of (IV) and the ꢀGlcp rings of
(III) [’ = 28 (6)ꢂ] are slightly distorted near 0H1; these
conformations differ from the ꢀGalp ring of (II) and the
ꢀGlcp rings of (II) and (IV) which are distorted near E5 and
0E/0H5, respectively.
In the DFT-calculated structure (IIC), trends in C—C bond
lengths mimic the experimental observations, but calculated
C—C bond lengths are longer on average than experimental
˚
˚
values by ꢃ0.01 A: C1—C2 = 1.531 (3) A; remaining endo-
˚
˚
cyclic C—C = 1.532 (8) A; C5—C6 = 1.525 (3) A. In contrast,
DFT-calculated C—O bond lengths reproduce the experi-
mental data well, both in terms of trends and absolute values:
˚
endocyclic C—O = 1.426 (6) A; anomeric C—O (exocyclic) =
˚
1.393 (6) A; exocyclic C—O = 1.421 (6) A; exocyclic C—O
˚
˚
involving the anomeric oxygen = 1.430 A.
The C40—O40 bond lengths in (II) and (III) are identical
despite differences in C4 configuration (Table 1). The C40—
Exocyclic hydroxymethyl (–CH2OH) conformations in (II)–
(IV), denoted by torsion angle !, differ. In (II), the gt
(gauche–trans) conformation is found in both residues,
whereas in (III), gg (gauche–gauche) conformations are
observed (Table 1), resulting in significantly different surface
topologies for the two disaccharides. In contrast, mixed
conformations are found in (IV), viz. gg in ꢀGlcp and gt in
ꢀGalp. The gt conformation is highly favored in methyl ꢀ-d-
galactopyranoside in aqueous solution, based on NMR scalar
coupling analysis, whereas a roughly equal mixture of gg and
gt forms is observed in methyl ꢀ-d-glucopyranoside (Thibau-
deau et al., 2004), results consistent with the statistical distri-
bution of rotamers observed in (II)–(IV).
Glycosidic linkage conformation in (II) is determined by
0
torsion angles ’0 [C20—C10—O10—C6 = 172.9 (2)ꢂ], [C10—
O10—C6—C5 = ꢁ117.9 (3)ꢂ] and ! [O10—C6—C5—O5 =
63.8 (3)ꢂ]. These torsions contrast with corresponding values
of ꢁ176.4, ꢁ156.3 and ꢁ61.6ꢂ observed in (III). The ’0 values
0
differ by ꢃ11ꢂ, whereas the values differ by ꢃ38ꢂ.
Figure 1
The crystal structure and atom-labeling scheme of (II). Displacement
ellipsoids are depicted at the 50% probability level.
Presumably, different conformations about ! and !0 in (II)
and (III) influence 0, which is controlled mainly by steric
ꢄ
o602 Klepach et al. C13H24O11ꢀH2O
Acta Cryst. (2009). C65, o601–o606

organic compounds
factors rather than the stereoelectronic (exoanomeric;
Lemieux, 1971) factors that largely influence ’0. It is note-
worthy that ’0 values in (II)–(III) are larger than the corre-
sponding value in (IV) (153.8ꢂ), which suggests reduced steric
constraints for the linkage in the former and leading to nearly
ideal, i.e. perfectly staggered, exoanomeric conformations for
both C10—O10 bonds.
ꢀGal(1!6)ꢀGlc structure is deformed upon protein binding
(Table 3). The glycosidic torsions ’0 are very similar for (II)
and (IG1–G3) (C20—C10—O10—C6 torsions of 170.0–174.0ꢂ),
but 0 values differ considerably (C10—O10—C6—C5 torsions
of ꢁ117.9 to ꢁ168.3ꢂ). Cremer–Pople ꢁ values are similar for
the ꢀGalp residue in the free and protein-bound states
(Table 2). However, considerable ꢀGlcp ring distortion is
observed in the bound state, as indicated by the significantly
enhanced ꢁ values (Table 2), and the direction of distortion
varies widely in the bound geometries. Equally important,
exocyclic hydroxymethyl conformation is affected by binding:
bound ꢀGalp residues assume the tg (trans–gauche) confor-
mation, whereas gg or gt is adopted in the ꢀGlcp residues
(Table 3). In solution, ꢀGalp residues prefer gt and tg
conformations, with gg virtually absent (Thibaudeau et al.,
2004). The statistical findings for !0 in bound conformations of
(Iꢀ) are thus consistent with solution behavior. Similar argu-
ments apply to the ꢀGlcp residue.
Linkage conformation in the DFT-calculated structure (IIC)
0
is similar to that in (II); the glycosidic torsion angles ’0 and
differ by ꢃ12ꢂ (Table 1). While Cremer–Pople ꢁ values differ
by < 2.4ꢂ, the types of ring distortions in (II) and (IIC) differ,
especially for the ꢀGalp ring, where ’ values differ by ꢃ90ꢂ
(Table 2). The discrepancy may be linked to a change in
hydrogen bonding involving the C30 and C40 hydroxy groups
from the intermolecular arrangement in (II) (see below) to an
intramolecular hydrogen bond (O40ꢀ ꢀ ꢀO30) in (IIC) [rO3 ,O4 in
0
0
˚
(IIC) = 2.693 A]. Ring-puckering amplitudes, Q, decrease by
3.2 and 3.5% for the ꢀGalp and ꢀGlcp residues, respectively,
in (IIC) relative to (II).
Crystal structures of mutant ꢀ-galactosidase complexed
with (Iꢀ) (Juers et al., 2001) reveal the degree to which the
Ring pucker can exert an important effect on glycosidic
linkage conformation; deformation of one or both pyranose
rings in a ꢀ-(1!6) linkage may allow conformations that are
not normally accessible. For example, inspections of (IG1–G3
)
and (III) reveal a qualitative correlation between departure
4
from an ideal C1 conformation and linkage conformation
(Fig. 2). This connectivity suggests that, in solution, a corre-
lation between pyranose ring-puckering dynamics and linkage
reorientation may exist. Related behavior has been observed
previously in nucleosides (Foloppe & Nilsson, 2005). While
furanosyl rings are commonly viewed as more conformation-
ally flexible than pyranosyl rings (Altona & Sundaralingam,
1972, 1973; French & Finch, 1999), pyranose pseudorotation
may become more energetically favorable by extrinsic
macromolecular forces. This expectation appears to be borne
out in the structures of (Iꢀ) bound to mutant ꢀ-galactosidase.
The crystal structure of (II) contains no intramolecular
hydrogen bonds. Six of the seven hydroxy groups (O3, O4,
O20, O30, O40 and O60) participate as donors in strong inter-
molecular hydrogen bonds, while the remaining hydroxy
group, O2, has longer contacts and is bifurcated between O20
and O30 (Table 4 and Fig. 3). Of the seven exocyclic hydroxy O
atoms present in (II), five (O2, O3, O30, O40, O60) participate
in intermolecular hydrogen bonding as monoacceptors.
Hydroxy atom O20 accepts hydrogen bonds from two donors;
one is a weaker bifurcated hydrogen bond described above
Figure 2
Stereographic projection of the pyranose pseudorotational itinerary
(northern hemisphere only) with ring-puckering coordinates for (I)–(IV).
Ring-puckering parameters ’ and ꢁ are represented by angular and radial
displacements about the 4C1 origin (center point), respectively, and
displacements are based on individual total puckering amplitudes, Q. In
the inset, displacements are based on an average amplitude for the
depicted data (Qavg = 0.5734). Inner and outer black rings represent the
minimal and maximal Q values for the total data set; colored rings
correspond to Q values for the Gal and Glc rings of (II) and (IIC) as per
the color code shown below the graphic. The southern hemisphere (not
shown) relates via symmetry to the northern with 1C4 at the origin. Note:
(a) ring at the nonreducing end of (III) is Glc not Gal.
Figure 3
The hydrogen-bonding scheme in the title compound, viewed along the a
axis.
ꢄ
Acta Cryst. (2009). C65, o601–o606
Klepach et al. C13H24O11ꢀH2O o603

organic compounds
and the other a more regular hydrogen bond from O60. The
remaining exocyclic hydroxy group, O4, does not receive
hydrogen bonds. The two endocyclic O atoms (O5 and O50)
and the internal glycosidic O atom (O10) are not hydrogen
bonded. The remaining terminal glycosidic O atom (O1)
serves as a monoacceptor. The water of crystallization (O1W)
participates as a node, accepting and donating two hydrgoen
bonds.
the Nichrome wire to heat the ascending arm to ꢃ323 K. After 10 d, a
tiny needle-shaped crystal formed in the cooler descending arm of the
ꢂ tube. This crystal was carefully removed, placed in a capped vial
with mother liquor that had been significantly reduced in volume, and
the vessel was set at room temperature. The vial was not tightly
capped so as to allow slow evaporation of solvent. After about 18
months, colorless needle-shaped crystals formed, which were
harvested for structure determination.
Crystallographic data were collected through the SCrALS (Service
Crystallography at Advanced Light Source) program at the Small-
Crystal Crystallography Beamline 11.3.1 (developed by the Experi-
mental Systems Group) at the Advanced Light Source (ALS).
An intermolecular hydrophobic contact in the crystal is
observed between the methyl aglycone and the ꢀGlcp H6R
and H6S hydrogens adjacent to the glycoside from a neigh-
boring unit cell, with methyl–hydroxymethyl Hꢀ ꢀ ꢀH inter-
˚
Crystal data
nuclear distances of 2.602 and 2.522 A, respectively. The third
methyl H atom has a weaker intramolecular contact with H10
3
˚
C13H24O11ꢀH2O
V = 822.6 (8) A
Z = 2
Synchrotron radiation
˚
(3.014 A).
Mr = 374.34
Monoclinic, P21
˚
˚
˚
a = 7.528 (2) A
b = 8.744 (4) A
ꢂ = 0.77490 A
ꢃ = 0.14 mmꢁ1
T = 150 K
˚
c = 12.695 (11) A
ꢀ = 100.15 (4)ꢂ
Experimental
0.12 ꢅ 0.06 ꢅ 0.01 mm
The reagents o-nitrophenol, Sepharose G10, Dowex 1 ꢅ 2 (200–400
mesh) (Clꢁ) ion-exchange resin, ꢀ-galactosidase (E. C. 3.2.1.23) (E.
coli) and methyl ꢀ-d-glucopyranoside were purchased from Sigma.
For the synthesis of o-nitrophenyl ꢀ-d-[1-13C]galactopyranoside,
d-[1-13C]galactose was prepared from d-lyxose and K13CN
(Cambridge Isotope Laboratories; 99 atom% 13C) by cyanohydrin
reduction, yielding d-[1-13C]galactose and d-[1-13C]talose (Serianni et
al., 1979, 1990). The galacto and talo epimers were separated by
chromatography on Dowex 50 ꢅ 8 (200–400 mesh) (Ca2+) (Angyal et
al., 1979), with the galacto isomer eluting first. o-Nitrophenyl ꢀ-d-
[1-13C]galactopyranoside was prepared from d-[1-13C]galactose in an
overall yield of 30% (Conchie & Levvy, 1963).
Table 1
Structural parameters (A, ) for (II), (IIC), (III) and (IV).
ꢂ
˚
Bond distance standard uncertainties for (III) were not provided in the
˚
original article but were stated as being in the range 0.002–0.003 A.
(II)
(IIC)
(III)
(IV)
C1—C2
C2—C3
C3—C4
C4—C5
C5—C6
C10—C20
C20—C30
C30—C40
C40—C50
C50—C60
C1—O1
C1—O5
C2—O2
C3—O3
C4—O4
C5—O5
C6—O6
C10—O10
C10—O50
C20—O20
C30—O30
C40—O40
C50—O50
C60—O60
C4—O10
C6—O10
1.525 (4)
1.532 (4)
1.540 (4)
1.521 (4)
1.515 (4)
1.528 (4)
1.526 (4)
1.536 (4)
1.523 (4)
1.510 (4)
1.397 (4)
1.408 (3)
1.439 (4)
1.432 (3)
1.419 (3)
1.427 (3)
1.529
1.524
1.527
1.538
1.523
1.533
1.524
1.545
1.533
1.527
1.388
1.425
1.420
1.422
1.418
1.429
1.521
1.515
1.514
1.528
1.510
1.515
1.526
1.521
1.533
1.514
1.393
1.428
1.420
1.433
1.438
1.430
1.516 (3)
1.519 (3)
1.531 (3)
1.530 (3)
1.508 (3)
1.527 (3)
1.531 (3)
1.521 (3)
1.521 (3)
1.511 (3)
1.384 (3)
1.413 (3)
1.418 (3)
1.421 (3)
For the synthesis of (II) by enzyme-catalyzed transglycosylation,
the conditions for the transglycosylation reaction were identical to
those reported by Nilsson (1987, 1988); the reaction was conducted
with 1.35 g (4.48 mmol) of the acceptor (methyl ꢀ-d-glucopyran-
oside) and 2.50 g (12.9 mmol) of the donor (o-nitrophenyl ꢀ-d-
[1-13C]galactopyranoside). After the reaction was quenched, the
mixture was concentrated in vacuo at 313 K to ꢃ45 ml and applied to
a column (2.5 ꢅ 55 cm) of Sepharose G10. Elution with distilled
water gave a phenol–sulfuric acid (Hodge & Hofreiter, 1962) positive
peak near the column void volume. This disaccharide-containing
fraction was collected, concentrated to ꢃ35 ml, and the solution was
applied to a column (2.5 ꢅ 55 cm) of Dowex 1 ꢅ 2 (200–400 mesh)
(OHꢁ) ion-exchange resin (Austin et al., 1963). Elution with distilled
water (3.8 ml fractionꢁ1, 0.8 ml minꢁ1) gave three phenol–sulfuric
acid positive peaks. NMR analysis of each peak indicated the
following: peak 1, residual acceptor; peak 2, (II); peak 3, methyl ꢀ-d-
[1-13C]galactopyranosyl-(1!3)-ꢀ-d-glucopyranoside (by-product).
Fractions containing (II) were pooled and the volume reduced to give
1.428 (3)
1.424 (3)
1.387 (3)
1.425 (3)
1.414 (3)
1.422 (3)
1.423 (3)
1.432 (3)
1.426 (3)
1.437 (3)
1.400 (3)
1.426 (3)
1.422 (4)
1.413 (3)
1.434 (4)
1.442 (3)
1.437 (4)
1.397
1.418
1.419
1.433
1.415
1.432
1.418
1.390
1.415
1.427
1.422
1.433
1.424
1.426
1.441 (3)
1.430
1.425
113.3
C10—O10—C4
C10—O10—C6
C1—O1—C7
116.2 (2)
113.7 (2)
1
a clear colorless viscous syrup for characterization by H and 13C
114.2 (2)
112.3 (2)
115.4
114.3
NMR.
Crystals of (II) suitable for X-ray diffraction were grown using a ꢂ
tube (Gravatt & Gross, 1969) and a modification of published
protocols (Hope, 1971). Approximately 20 mg of (II) were dissolved
in 300 ml of distilled water and the solution was placed in the sample
reservoir of a ꢂ tube. A Nichrome wire was wrapped around the arm
closer to the sample reservoir for heating purposes, and a length of
copper wire was closely wound around the cross arm to act as cooling
ribs. The apparatus was gently filled with a 1:3:6 (v/v/v) mixture of n-
butanol–methanol–ethanol to a level above the cross arm, the open
ends were stoppered, and a low electric current was applied across
C2—C1—O1—C7 (’)
C20—C10—O10—C6 (’0)
C20—C10—O10—C4 (’0)
177.4 (3)
172.9 (2)
167.4
160.8
164.2 (2)
ꢁ176.4
ꢁ156.3
153.8 (2)
C10—O10—C6—C5 ( 0) ꢁ117.9 (3)
ꢁ104.6
C10—O10—C4—C5 ( 0)
O5—C5—C6—O10 (!)
ꢁ161.3 (2)
ꢁ54.6 (2) (gg)
63.8 (3) (gt)
61.8 (gt) ꢁ61.6 (gg)
O5—C5—C6—O6 (!)
C4—C5—C6—O10 (!) ꢁ176.2 (2)
ꢁ177.5
59.5
C4—C5—C6—O6 (!)
66.4
57.3 (2) (gt)
177.8
O50—C50—C60—O60 (!0)
59.5 (3) (gt)
59.5 (gt) ꢁ53.7 (gg)
C40—C50—C60—O60 (!0) 179.9 (2)
ꢁ177.9
66.1
Notes: gt is gauche–trans; gg is gauche–gauche.
ꢄ
o604 Klepach et al. C13H24O11ꢀH2O
Acta Cryst. (2009). C65, o601–o606

organic compounds
Table 2
Cremer–Pople pyranosyl ring-puckering parameters for (II), (IIC), (III),
(IG1–G3) and (IV).
Table 3
Structural parameters (ꢂ) for (IG1–G3).
(IG1
)
(IG2
)
(IG3)
q2
q3
Q
’ (ꢂ)
ꢁ (ꢂ)
C10—O10—C6
111.9
114.3
109.0
ꢀGalp ring†
II
IIC
C20—C10—O10—C6 (’0)
C10—O10—C6—C5 ( 0)
O5—C5—C6—O10 (!)
C4—C5—C6- O10 (!)
O50—C50—C60—O60 (!0)
C40—C50—C60—O60 (!0)
174.0
ꢁ158.4
170.0
ꢁ168.3
171.0
ꢁ162.4
ꢁ86.8 (gg)
32.7
0.0877
0.0620
0.0481
0.0414
0.0356
0.0159
0.0485
0.5700
0.5545
0.5491
0.5730
0.5850
0.5532
0.5928
0.5767
0.5580
0.5512
0.5745
0.5861
0.5534
0.5948
312.8
39.8
33.3
18.2
353.6
28.0
28.2
8.8
6.4
5.0
4.1
3.5
1.7
4.7
69.4 (gt)
66.0 (gt)
III
ꢁ169.7
ꢁ176.0
IG1
IG2
IG3
IV
ꢀGlcp ring
II
IIC
ꢁ179.7 (tg)
ꢁ56.3
ꢁ171.6 (tg)
ꢁ50.8
ꢁ179.7 (tg)
ꢁ57.7
Notes: gt is gauche–trans; gg is gauche–gauche; tg is trans–gauche.
0.0237
0.0279
0.0756
0.2363
0.3039
0.1737
0.1159
0.5999
0.5785
0.5763
0.5088
0.4793
0.5589
0.5475
0.6004
0.5791
0.5812
0.5610
0.5675
0.5852
0.5579
6.4
37.2
22.3
19.5
347.5
159.1
341.5
2.3
2.8
7.5
24.9
32.4
17.3
12.0
Table 4
Hydrogen-bond geometry (A, ).
ꢂ
III
˚
IG1
IG2
IG3
IV
D—Hꢀ ꢀ ꢀA
D—H
Hꢀ ꢀ ꢀA
Dꢀ ꢀ ꢀA
D—Hꢀ ꢀ ꢀA
i
O2—H2ꢀ ꢀ ꢀO20
O2—H2ꢀ ꢀ ꢀO30
O3—H3ꢀ ꢀ ꢀO40
0.84
0.84
0.84
0.84
0.84
0.84
0.84
0.84
2.38
2.58
1.90
2.03
1.90
1.99
1.87
1.95
3.089 (3)
3.280 (3)
2.695 (3)
2.828 (3)
2.693 (3)
2.796 (4)
2.698 (4)
2.781 (3)
2.750 (3)
2.724 (3)
142
141
157
157
156
162
169
170
i
† In (III), the ꢀGalp ring is replaced by a ꢀGlcp ring.
ii
O4—H4ꢀ ꢀ ꢀO1Wiii
O20—H20ꢀ ꢀ ꢀO1iv
O30—H30ꢀ ꢀ ꢀO3v
O40—H40ꢀ ꢀ ꢀO1Wvi
Data collection
Bruker D8 APEXII CCD
diffractometer
Absorption correction: multi-scan
(SADABS; Sheldrick, 2007)
Tmin = 0.984, Tmax = 0.999
10449 measured reflections
2192 independent reflections
1920 reflections with I > 2ꢄ(I)
Rint = 0.087
vii
O60—H60ꢀ ꢀ ꢀO20
O1W—H1WAꢀ ꢀ ꢀO2i
0.829 (19)
0.840 (19)
1.93 (2)
1.89 (2)
168 (4)
170 (4)
viii
O1W—H1WBꢀ ꢀ ꢀO60
1
2
1
2
1
2
Symmetry codes: (i) ꢁx þ 2; y þ ; ꢁz þ 1; (ii) ꢁx þ 1; y þ ; ꢁz þ 1; (iii) ꢁx þ 1; y ꢁ ,
1
2
1
2
ꢁz þ 1; (iv) ꢁx þ 2; y ꢁ ; ꢁz þ 1; (v) x; y; z ꢁ 1; (vi) ꢁx þ 1; y ꢁ ; ꢁz; (vii) x ꢁ 1; y; z;
(viii) x þ 1; y; z.
Refinement
R[F2 > 2ꢄ(F2)] = 0.049
wR(F2) = 0.121
S = 1.05
2192 reflections
239 parameters
3 restraints
H atoms treated by a mixture of
independent and constrained
refinement
at Beamline 11.3.1 at the Advanced Light Source (ALS),
Lawrence Berkeley National Laboratory. The ALS is
supported by the US Department of Energy, Office of Energy
Sciences, Materials Sciences Division, under contract No. DE-
AC02-05CH11231 at Lawrence Berkeley National Labora-
tory.
ꢁ3
˚
Áꢅmax = 0.41 e A
ꢁ3
˚
Áꢅmin = ꢁ0.39 e A
All H atoms were located from a difference Fourier map. Carbon-
bound and hydroxy H atoms were subsequently treated as riding
atoms in geometrically idealized positions, with C—H distances of
˚
1.00 (methine), 0.99 (methylene) or 0.98 A (methyl) and O—H
˚
distances of 0.84 A. The H atoms on the water of crystallization were
˚
restrained to have O—H distances of 0.84 (2) A. For all H atoms,
Supplementary data for this paper are available from the IUCr electronic
archives (Reference: MX3023). Services for accessing these data are
described at the back of the journal.
Uiso(H) = kUeq(carrier), where k = 1.5 for the methyl groups, which
were permitted to rotate but not to tilt, and k = 1.2 for all other H
atoms.
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