β-d-Galacto­pyranosyl-(1→4)–2-amino-2-de­oxy-α-d-gluco­pyran­ose hydro­chloride monohydrate (lactosamine)

Mossine, V.V.; Kelley, S.P.; Mawhinney, T.P.

doi:10.1107/S241431462200061X

organic compounds

IUCrDATA

ISSN: 2414-3146

Volume 7| Part 1| January 2022| x220061

https://doi.org/10.1107/S241431462200061X

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β-D-Galactopyranosyl-(1→4)–2-amino-2-deoxy-α-D-glucopyranose hydrochloride monohydrate (lactosamine)

Valeri V. Mossine,^a ^* Steven P. Kelley ^b and Thomas P. Mawhinney ^a

^aDepartment of Biochemistry, University of Missouri, Columbia, MO 65211, USA, and ^bDepartment of Chemistry, University of Missouri, Columbia, MO 65211, USA
^*Correspondence e-mail: mossinev@missouri.edu

Edited by J. F. Gallagher, Dublin City University, Ireland (Received 3 November 2021; accepted 17 January 2022; online 28 January 2022)

The title compound, C₁₂H₂₄NO₁₀⁺·Cl⁻·H₂O, (I), crystallizes in the monoclinic space group P2₁ and exists as a monohydrate of a monosubstituted ammonium chloride salt, with the reducing carbohydrate portion existing exclusively as the α-pyranose tautomer. The glycosidic bond geometry in (I) is stabilized by an intramolecular hydrogen bond and is close to that found in crystalline α-lactose. All heteroatoms except glucopyranose ring O4 participate in an extensive hydrogen-bonding network, which propagates in all directions in the crystal structure of (I).

Keywords: crystal structure; glycosidic bond geometry; Heyns rearrangement; hydrogen bonding.

CCDC reference: 2119923

Structure description

Lactosamine is an important endogenous and food-related glycoepitope that provides for recognition of glycoproteins by both plant and animal β-galactoside-specific lectins, such as tomato lectin (Acarin et al., 1994 ) or a family of mammalian galectins (Boscher et al., 2011 ; Mossine et al., 2008 ). In free and oligomeric form, N-acetyllactosamine is present in human milk and is believed to participate in the immune protection of infants (Kulinich & Liu, 2016 ). Therefore, structural aspects of lactosamine interaction with carbohydrate-recognizing proteins are of significant interest to the biomedical glycobiology field (Seetharaman et al., 1998 ; Guardia et al., 2011 ). As a part of our research program on the structure and anti-tumorigenic potential of aminoglycoconjugates (Glinskii et al., 2012 ; Mossine et al., 2018 ), we have prepared a number of 2-amino-2-deoxysaccharides, including lactosamine. Although the crystal parameters and hydrogen-bonding geometry of (I) were previously reported in a patent (Dekany et al., 2014 ), no other structural data have been provided. Here we report details of the molecular geometry of (I) and compare it to related disaccharide structures.

The molecular structure and atomic numbering for the title compound (I) are shown in Fig. 1. Lactosamine is a disaccharide made of the non-reducing β-D-galactoside unit and the D-glucosamine portion, which is a reducing end sugar moiety and thus can exist in several tautomeric forms, such as α- and β-pyranose, or α- and β-furanose. In the crystalline state of (I), the D-glucosamine residue exists exclusively as the α-pyranose anomer, which is also a predominant tautomer in aqueous solutions of lactosamine (Dekany et al., 2014). The amino group in (I) is fully protonated, as would be expected for a hydrochloride salt. The conformation of the D-glucosamine α-pyranose ring is a relaxed ⁴C₁ chair, with puckering parameters Q₁ = 0.579 (8) Å, θ₁ = 1.0 (8)°, and φ₁ = 100 (27)°. The D-galactoside β-pyranose ring similarly adopts the ⁴C₁ conformation, with puckering parameters Q₂ = 0.607 (8) Å, θ₂ = 2.0 (8)°, and φ₂ = 123 (38)°.

Figure 1
Atomic numbering and displacement ellipsoids at the 50% probability level for (I). Hydrogen bonds are shown as dotted lines.

The conformation around the β1→4 glycosidic link in disaccharide (I) is an important structural characteristic and, for the purpose of the structure comparison, can be conventionally described by the valence angle C4—O5—C7 (also referred to as `τ′), torsion angles C4—O5—C7—O10 (`Φ′) and C3—C4—O5—C7 (`Ψ'). As can be seen in Table 1, values of these angles are typical for other Gal-β1→4-Glc disaccharides, with α-lactose monohydrate (Smith et al., 2005 ) being conformationally the closest structure to (I). It is believed that the O10⋯H—O2 intramolecular hydrogen bond linking the two carbohydrate units is primarily responsible for stabilization of the spatial arrangement around the glycosidic bond, both in the crystal state and in solutions of Gal-β1→4-Glc di- and oligosaccharides (Imberty et al. 1991 ). Moreover, this contact may be further stabilized by its involvement in multicenter hydrogen-bonding patterns. For instance, the H2 proton is involved in bifurcated hydrogen bonding with the O5 and O10 acceptors in (I) and α-lactose (Tables 2 and 3), while in N-acetyllactosamine (Longchambon et al., 1981 ) and N-acetyllactosylamine (Lakshmanan et al., 2001 ), additional intramolecular links between the galactopyranoside and glucopyranose moieties are represented by the O5⋯H6—O6 and the O9⋯H2—O2 contacts, respectively (Table 2).

Table 1
Conformational features (Å, °) of the glycosidic bond in (I) and related disaccharide structures with the Gal-β1→4-Glc link

Sugar	Tautomer, conformation	τ	Φ	Ψ	Intramolecular contacts around glycosidic bond (O⋯H; O⋯O; O⋯H—O)
Gal-β1→4-GlcNH₃⁺Cl⁻·H₂O (I)^a	α-pyranose, ⁴C₁	116.0	−95.2	+90.7	O10⋯H—O2 (1.98; 2.743; 159) O5⋯H—O2 (2.64; 2.964; 106)
Gal-β1→4-GlcNHCOCH₃·H₂O (N-acetyllactosamine, LacNAc·H₂O)^b	α-pyranose, ⁴C₁^b	116.3	−88.1	+97.8	O10⋯H—O2 (1.98; 2.787; 139) O5⋯H—O6 (2.40; 2.868; 122)
LacNAc/ toad galectin^c	α-pyranose, ⁴C₁	118.2; 113.6	−66.9; −67.8	+132.4; +132.6	Not reported
LacNAc calculations^d	α-pyranose, ⁴C₁^d	117.1	−75	+135	O10⋯H—O2
Gal-β1→4-Glc·H₂O (α-lactose)^e	α-pyranose, ⁴C₁	116.9	−93.4	+95.9	O10⋯H—O2 (2.02; 2.819; 159) O5⋯H—O2 (2.65; 2.992; 106)
Gal-β1→4-Glc (β-lactose)^f	β-pyranose, ⁴C₁	116.5	−76.3	+106.4	O10⋯H—O2 (n.d.; 2.707; 101)
Gal-β1→4-GlcNHCOCH₃·2H₂O (N-acetyllactosylamine)^g	β-pyranose, ⁴C₁	117.4	−89.3	+81.5	O10⋯H—O2 (2.06; 2.767; 144) O9⋯H—O2 (2.45; 3.126; 141)
Notes: (a) This work; (b) Longchambon et al. (1981); (c) Bianchet et al. (2000 ); (d) Imberty et al. (1991); (e) Smith et al. (2005); (f) Hirotsu & Shimada (1974 ); (g) Lakshmanan et al. (2001).

Table 2
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O1—H1⋯Cl1	0.83 (5)	2.28 (6)	3.075 (6)	163 (9)
O2—H2⋯O10	0.80 (5)	1.98 (6)	2.743 (7)	159 (8)
O3—H3⋯Cl1ⁱ	0.82 (5)	2.31 (6)	3.130 (7)	172 (9)
O6—H6⋯O9ⁱⁱ	0.82 (5)	1.84 (6)	2.654 (8)	171 (9)
O7—H7⋯O2ⁱⁱⁱ	0.81 (5)	1.92 (6)	2.697 (8)	158 (9)
O8—H8⋯Cl1^iv	0.78 (5)	2.32 (6)	3.080 (5)	166 (8)
O9—H9⋯O6^v	0.83 (5)	1.88 (5)	2.707 (8)	178 (9)
N1—H1A⋯O1W	0.90 (4)	1.96 (5)	2.819 (9)	159 (7)
N1—H1B⋯O7^vi	0.90 (4)	2.26 (7)	2.862 (8)	124 (6)
N1—H1B⋯O8^vi	0.90 (4)	2.16 (6)	2.922 (8)	142 (7)
N1—H1C⋯O1	0.91 (4)	2.34 (8)	2.787 (9)	110 (6)
N1—H1C⋯O1W^vii	0.91 (4)	2.35 (6)	3.162 (11)	149 (7)
O1W—H1WA⋯O3^viii	0.90 (6)	1.85 (7)	2.746 (8)	170 (10)
O1W—H1WB⋯Cl1^ix	0.89 (6)	2.50 (7)	3.335 (7)	156 (9)
Symmetry codes: (i) $[-x, y-{\script{1\over 2}}, -z+1]$ ; (ii) $[-x, y-{\script{1\over 2}}, -z]$ ; (iii) $[-x+1, y-{\script{1\over 2}}, -z]$ ; (iv) ; (v) $[-x+1, y+{\script{1\over 2}}, -z]$ ; (vi) $[-x, y+{\script{1\over 2}}, -z]$ ; (vii) ; (viii) $[-x+1, y+{\script{1\over 2}}, -z+1]$ ; (ix) $[-x, y+{\script{1\over 2}}, -z+1]$ .

Table 3
Additional D—H⋯A contacts (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O2—H2⋯O5	0.80 (7)	2.64 (8)	2.964 (8)	106 (6)
N1—H1B⋯O2	0.90 (6)	2.55 (7)	2.855 (9)	101 (5)
O7—H7⋯O6	0.81 (8)	2.63 (8)	2.847 (8)	97 (8)
C2—H2A⋯O1ⁱ	0.98	2.34	3.199 (10)	146
C9—H9A⋯O8ⁱ	0.98	2.58	3.309 (9)	132
C10—H10⋯Cl1ⁱⁱ	0.98	2.82	3.741 (9)	157
Symmetry codes: (i) x + 1, y, z; (ii) x + 1, y, z − 1.

The molecular packing of (I) features an extensive intermolecular hydrogen-bonding network (Table 2), which propagates in all directions (Fig. 2). The ammonium groups, chloride ions, and water molecules serve as the hydrogen-bonding network `hubs', each being in short, H-mediated, contact with four or five heteroatoms. For the ammonium group, these are O1, O7, O8, and two different O1W; the chloride ions are in contact with O1, O3, O8, and O1W; the water molecules are involved in the network by serving as both donors (to Cl1 and O3) and acceptors (to two different H1A—N1—H1C groups) of strong hydrogen bonding (Table 2). In this way, each molecule of lactosamine is surrounded by four hydrogen-bonded molecules of lactosamine, three water molecules, and three chloride ions (Fig. 3); each water molecule coordinates three lactosamines and one chloride (Fig. 4); every chloride is hydrogen-bonded to three lactosamines and one water as well (Fig. 2).

Figure 2
The molecular packing in (I) as viewed along the c axis. Hydrogen bonds are shown as cyan dotted lines.

Figure 3
Hydrogen-bonded lactosamine molecular ions, chloride ions, and water molecules surrounding the central lactosamine molecular ion in the crystal structure of (I).

Figure 4
Hydrogen-bonded coordination sphere around the water molecule in the crystal structure of (I)

Synthesis and crystallization

The synthesis of (I) was performed following a Heyns rearrangement protocol described previously by Wrodnigg & Stütz (1999 ). A mixture of 34.2 g (100 mmoles) of D-lactulose and 75 ml (700 mmoles) of benzylamine was stirred for 18 h in a screw-capped glass flask at 318 K. The reaction progress was followed by TLC. The excess of benzylamine was removed by four successive extractions with benzene (2 L total), the residue was dissolved in 500 ml MeOH containing 20 ml of glacial acetic acid and left for 18 h at room temperature. The reaction mixture was then hydrogenated in the presence of 2.0 g of 10% Pd/C and 5 ml of 80% formic acid, until the reaction was judged complete by TLC. After filtration, the solvents were removed under reduced pressure, a syrupy residue was dissolved in 1.5 L of water and passed through a column charged with 250 ml of ion-exchange resin Amberlite IRN-77 (H⁺-form). The column was washed with water and eluted with 0.2 M ammonium acetate. The eluate fractions containing lactosamine were pooled, evaporated to a syrup, re-dissolved in 0.5 L of water and passed through a column filled with 1L of Amberlite IRN-78 (Cl⁻). The eluate fractions containing (I) were pooled, evaporated to a syrup, and the syrup was kept at 277 K to produce crystalline material suitable for the X-ray diffraction studies.

Refinement

Crystal data, data collection and structure refinement details are summarized in Table 4. The Flack absolute structure parameter determined [0.02 (11) for 729 quotients (Parsons et al., 2013 )] is consistent with the (3S,4R,5R,7S,8R,9S,10S,11R) configuration, which was assigned for this system on the basis of the known configuration for the starting material D-lactulose (McNaught, 1996 ). Data were collected out to 0.80 Å; however, because of the small size of the crystal, most of the high-angle diffraction peaks are effectively indistinguishable from the noise. The inclusion of this high-angle data results in a high value for R_int, and the precision of the bond distances is low (ca 0.01 Å) because most of the high-angle data are not usable for refinement.

Table 4
Experimental details

Crystal data
Chemical formula	C₁₂H₂₄NO₁₀⁺·Cl⁻·H₂O
M_r	395.79
Crystal system, space group	Monoclinic, P2₁
Temperature (K)	273
a, b, c (Å)	4.785 (4), 13.523 (11), 13.254 (11)
β (°)	93.940 (9)
V (Å³)	855.5 (12)
Z	2
Radiation type	Mo Kα
μ (mm⁻¹)	0.28
Crystal size (mm)	0.08 × 0.05 × 0.01

Data collection
Diffractometer	Bruker APEXII area detector
Absorption correction	Multi-scan (AXScale; Bruker, 2016 )
T_min, T_max	0.483, 0.746
No. of measured, independent and observed [I > 2σ(I)] reflections	11475, 3787, 2216
R_int	0.133
(sin θ/λ)_max (Å⁻¹)	0.643

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.066, 0.131, 1.01
No. of reflections	3787
No. of parameters	262
No. of restraints	26
H-atom treatment	H atoms treated by a mixture of independent and constrained refinement
Δρ_max, Δρ_min (e Å⁻³)	0.44, −0.37
Absolute structure	Flack x determined using 729 quotients [(I⁺)−(I⁻)]/[(I⁺)+(I⁻)] (Parsons et al., 2013)
Absolute structure parameter	0.02 (11)
Computer programs: APEX3 and SAINT (Bruker, 2016), SHELXS (Sheldrick, 2008 ), SHELXL2017/1 (Sheldrick, 2015 ), and OLEX2 (Dolomanov et al., 2009 ).

Structural data

CCDC reference: 2119923

Crystal structure: contains datablock I. DOI: https://doi.org/10.1107/S241431462200061X/gg4007sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S241431462200061X/gg4007Isup2.hkl

checkCIF report

Computing details top

Data collection: APEX3 (Bruker, 2016); cell refinement: APEX3 and SAINT (Bruker, 2016); data reduction: APEX3 and SAINT (Bruker, 2016); program(s) used to solve structure: SHELXS (Sheldrick, 2008); program(s) used to refine structure: SHELXL2017/1 (Sheldrick, 2015); molecular graphics: OLEX2 (Dolomanov et al., 2009); software used to prepare material for publication: OLEX2 (Dolomanov et al., 2009).

β-D-Galactopyranosyl-(1→4)–2-amino-2-deoxy-α-D-glucopyranose hydrochloride monohydrate top

Crystal data top

C₁₂H₂₄NO₁₀⁺·Cl⁻·H₂O	F(000) = 420
M_r = 395.79	D_x = 1.536 Mg m⁻³
Monoclinic, P2₁	Mo Kα radiation, λ = 0.71073 Å
a = 4.785 (4) Å	Cell parameters from 1276 reflections
b = 13.523 (11) Å	θ = 3.0–20.6°
c = 13.254 (11) Å	µ = 0.28 mm⁻¹
β = 93.940 (9)°	T = 273 K
V = 855.5 (12) Å³	Plate, colourless
Z = 2	0.08 × 0.05 × 0.01 mm

Data collection top

Bruker APEXII area detector diffractometer	2216 reflections with I > 2σ(I)
Radiation source: Sealed Source Mo with TRIUMPH optics	R_int = 0.133
ω and phi scans	θ_max = 27.2°, θ_min = 1.5°
Absorption correction: multi-scan (AXScale; Bruker, 2016)	h = −6→6
T_min = 0.483, T_max = 0.746	k = −17→17
11475 measured reflections	l = −17→16
3787 independent reflections

Refinement top

Refinement on F²	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: mixed
R[F² > 2σ(F²)] = 0.066	H atoms treated by a mixture of independent and constrained refinement
wR(F²) = 0.131	w = 1/[σ²(F_o²) + (0.0475P)²] where P = (F_o² + 2F_c²)/3
S = 1.01	(Δ/σ)_max < 0.001
3787 reflections	Δρ_max = 0.44 e Å⁻³
262 parameters	Δρ_min = −0.37 e Å⁻³
26 restraints	Absolute structure: Flack x determined using 729 quotients [(I⁺)-(I^-)]/[(I⁺)+(I^-)] (Parsons et al., 2013)
Primary atom site location: structure-invariant direct methods	Absolute structure parameter: 0.02 (11)

Special details top

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

Refinement. Hydroxy and nitrogen-bound H atoms were located in difference-Fourier analyses and were allowed to refine fully. Other H atoms were placed at calculated positions and treated as riding. All chemically equivalent N—H and O—H bond distances were restrained to be equal within 0.05 Å.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq
Cl1	−0.3280 (4)	0.75359 (14)	0.61589 (14)	0.0286 (5)
O1	−0.1394 (11)	0.7867 (4)	0.4014 (4)	0.0272 (13)
H1	−0.195 (16)	0.765 (7)	0.455 (5)	0.041*
O1W	0.6240 (15)	1.0329 (4)	0.4269 (5)	0.0462 (19)
H1WA	0.71 (2)	1.021 (8)	0.488 (6)	0.069*
H1WB	0.58 (2)	1.096 (5)	0.433 (8)	0.069*
O2	0.2355 (12)	0.8551 (4)	0.1351 (4)	0.0260 (14)
H2	0.186 (17)	0.830 (6)	0.082 (5)	0.039*
O3	0.1487 (12)	0.4761 (4)	0.3861 (4)	0.0341 (14)
H3	0.18 (2)	0.416 (4)	0.387 (7)	0.051*
O4	0.2482 (10)	0.6815 (4)	0.3919 (4)	0.0253 (13)
O5	0.1019 (10)	0.6413 (4)	0.1208 (4)	0.0223 (12)
O6	0.3161 (10)	0.4684 (4)	0.0307 (4)	0.0263 (12)
H6	0.175 (14)	0.446 (6)	0.055 (6)	0.039*
O7	0.3237 (11)	0.4742 (4)	−0.1838 (4)	0.0266 (13)
H7	0.431 (16)	0.434 (5)	−0.157 (6)	0.040*
O8	−0.0409 (10)	0.6292 (4)	−0.2120 (4)	0.0229 (12)
H8	−0.091 (17)	0.658 (6)	−0.261 (5)	0.034*
O9	0.1635 (11)	0.9157 (4)	−0.1046 (4)	0.0255 (13)
H9	0.321 (13)	0.933 (6)	−0.082 (6)	0.038*
O10	0.1420 (10)	0.7280 (3)	−0.0250 (4)	0.0226 (13)
N1	0.1495 (15)	0.9460 (5)	0.3249 (5)	0.0267 (17)
H1A	0.270 (14)	0.978 (6)	0.369 (5)	0.040*
H1B	0.104 (16)	0.980 (6)	0.268 (4)	0.040*
H1C	−0.023 (11)	0.946 (6)	0.350 (6)	0.040*
C1	0.1489 (16)	0.7791 (5)	0.4024 (6)	0.0250 (18)
H1D	0.231817	0.807016	0.465797	0.030*
C2	0.2409 (16)	0.8418 (5)	0.3134 (6)	0.0227 (18)
H2A	0.445983	0.840893	0.315433	0.027*
C3	0.1292 (16)	0.7968 (5)	0.2135 (6)	0.0228 (18)
H3A	−0.076034	0.799022	0.208350	0.027*
C4	0.2270 (15)	0.6906 (6)	0.2095 (6)	0.0224 (18)
H4	0.431371	0.689282	0.207687	0.027*
C5	0.1419 (16)	0.6315 (6)	0.3013 (5)	0.0226 (17)
H5	−0.062765	0.627481	0.300031	0.027*
C6	0.2641 (17)	0.5292 (6)	0.3051 (6)	0.030 (2)
H6A	0.219239	0.495436	0.241483	0.036*
H6B	0.466372	0.532736	0.316291	0.036*
C7	0.2534 (15)	0.6458 (6)	0.0341 (5)	0.0222 (17)
H7A	0.453220	0.655704	0.052771	0.027*
C8	0.2081 (16)	0.5518 (5)	−0.0258 (6)	0.0217 (17)
H8A	0.007235	0.542472	−0.042707	0.026*
C9	0.3596 (16)	0.5604 (5)	−0.1230 (5)	0.0204 (17)
H9A	0.559991	0.570369	−0.105595	0.024*
C10	0.2464 (15)	0.6483 (6)	−0.1834 (6)	0.0213 (17)
H10	0.350340	0.656234	−0.244111	0.026*
C11	0.2853 (15)	0.7402 (6)	−0.1168 (5)	0.0220 (17)
H11	0.485554	0.750477	−0.099407	0.026*
C12	0.1643 (16)	0.8313 (5)	−0.1692 (6)	0.0241 (18)
H12A	0.272384	0.846504	−0.226525	0.029*
H12B	−0.026310	0.817433	−0.194879	0.029*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Cl1	0.0323 (11)	0.0230 (11)	0.0302 (10)	−0.0014 (9)	−0.0006 (8)	0.0045 (10)
O1	0.027 (3)	0.023 (3)	0.032 (4)	0.002 (2)	0.004 (3)	0.004 (3)
O1W	0.075 (5)	0.027 (4)	0.034 (4)	−0.003 (3)	−0.012 (3)	−0.002 (3)
O2	0.035 (3)	0.021 (3)	0.022 (3)	−0.010 (2)	−0.001 (3)	0.001 (2)
O3	0.056 (4)	0.016 (3)	0.030 (3)	−0.003 (3)	0.004 (3)	0.007 (3)
O4	0.033 (3)	0.017 (3)	0.026 (3)	−0.002 (2)	−0.001 (3)	0.000 (2)
O5	0.027 (3)	0.021 (3)	0.020 (3)	−0.005 (2)	0.002 (2)	0.001 (2)
O6	0.025 (3)	0.021 (3)	0.033 (3)	0.001 (3)	0.005 (2)	0.006 (3)
O7	0.032 (3)	0.016 (3)	0.031 (3)	0.005 (2)	−0.001 (2)	−0.001 (3)
O8	0.025 (3)	0.019 (3)	0.024 (3)	−0.001 (2)	−0.001 (2)	0.004 (2)
O9	0.026 (3)	0.019 (3)	0.032 (3)	0.000 (2)	0.001 (3)	−0.003 (3)
O10	0.024 (3)	0.017 (3)	0.026 (3)	0.003 (2)	0.003 (2)	0.003 (2)
N1	0.035 (4)	0.021 (4)	0.023 (4)	−0.005 (3)	−0.006 (3)	0.004 (3)
C1	0.030 (5)	0.018 (4)	0.026 (4)	−0.002 (3)	−0.001 (3)	0.003 (3)
C2	0.025 (4)	0.016 (4)	0.026 (5)	−0.003 (3)	−0.001 (4)	0.004 (3)
C3	0.023 (4)	0.021 (4)	0.024 (4)	−0.002 (3)	0.002 (3)	0.008 (3)
C4	0.020 (4)	0.019 (4)	0.029 (5)	−0.004 (3)	0.000 (3)	0.000 (4)
C5	0.029 (4)	0.016 (4)	0.023 (4)	−0.009 (3)	−0.001 (3)	0.002 (3)
C6	0.037 (5)	0.023 (5)	0.028 (5)	−0.003 (4)	0.000 (4)	0.003 (4)
C7	0.023 (4)	0.021 (4)	0.023 (4)	0.001 (3)	0.002 (3)	0.004 (4)
C8	0.024 (4)	0.015 (4)	0.026 (5)	0.003 (3)	−0.002 (3)	0.005 (3)
C9	0.021 (4)	0.016 (4)	0.024 (4)	0.002 (3)	0.002 (3)	−0.001 (4)
C10	0.020 (4)	0.019 (4)	0.025 (4)	−0.002 (3)	0.004 (3)	0.003 (3)
C11	0.021 (4)	0.020 (4)	0.027 (4)	−0.001 (3)	0.007 (3)	−0.002 (4)
C12	0.026 (4)	0.014 (4)	0.032 (5)	0.001 (3)	0.004 (4)	0.000 (4)

Geometric parameters (Å, º) top

O1—C1	1.382 (9)	N1—H1C	0.91 (4)
O1—H1	0.83 (5)	C1—C2	1.541 (10)
O1W—H1WA	0.90 (6)	C1—H1D	0.9800
O1W—H1WB	0.89 (6)	C2—C3	1.521 (10)
O2—C3	1.426 (9)	C2—H2A	0.9800
O2—H2	0.80 (5)	C3—C4	1.512 (10)
O3—C6	1.434 (10)	C3—H3A	0.9800
O3—H3	0.82 (5)	C4—C5	1.533 (10)
O4—C1	1.414 (9)	C4—H4	0.9800
O4—C5	1.440 (8)	C5—C6	1.502 (11)
O5—C7	1.402 (9)	C5—H5	0.9800
O5—C4	1.445 (9)	C6—H6A	0.9700
O6—C8	1.431 (9)	C6—H6B	0.9700
O6—H6	0.82 (5)	C7—C8	1.507 (10)
O7—C9	1.420 (9)	C7—H7A	0.9800
O7—H7	0.81 (5)	C8—C9	1.526 (10)
O8—C10	1.424 (9)	C8—H8A	0.9800
O8—H8	0.78 (5)	C9—C10	1.513 (10)
O9—C12	1.426 (9)	C9—H9A	0.9800
O9—H9	0.83 (5)	C10—C11	1.528 (10)
O10—C7	1.441 (8)	C10—H10	0.9800
O10—C11	1.447 (8)	C11—C12	1.510 (10)
N1—C2	1.486 (10)	C11—H11	0.9800
N1—H1A	0.90 (4)	C12—H12A	0.9700
N1—H1B	0.90 (4)	C12—H12B	0.9700

C1—O1—H1	110 (6)	C6—C5—H5	109.6
H1WA—O1W—H1WB	101 (9)	C4—C5—H5	109.6
C3—O2—H2	108 (6)	O3—C6—C5	108.5 (7)
C6—O3—H3	115 (7)	O3—C6—H6A	110.0
C1—O4—C5	114.7 (5)	C5—C6—H6A	110.0
C7—O5—C4	116.0 (5)	O3—C6—H6B	110.0
C8—O6—H6	102 (6)	C5—C6—H6B	110.0
C9—O7—H7	105 (6)	H6A—C6—H6B	108.4
C10—O8—H8	112 (6)	O5—C7—O10	106.7 (5)
C12—O9—H9	114 (6)	O5—C7—C8	109.3 (6)
C7—O10—C11	111.5 (5)	O10—C7—C8	109.3 (5)
C2—N1—H1A	110 (5)	O5—C7—H7A	110.5
C2—N1—H1B	117 (5)	O10—C7—H7A	110.5
H1A—N1—H1B	114 (7)	C8—C7—H7A	110.5
C2—N1—H1C	109 (6)	O6—C8—C7	110.8 (6)
H1A—N1—H1C	109 (8)	O6—C8—C9	109.1 (6)
H1B—N1—H1C	97 (7)	C7—C8—C9	108.7 (6)
O1—C1—O4	114.2 (6)	O6—C8—H8A	109.4
O1—C1—C2	106.8 (6)	C7—C8—H8A	109.4
O4—C1—C2	108.8 (6)	C9—C8—H8A	109.4
O1—C1—H1D	109.0	O7—C9—C10	108.6 (6)
O4—C1—H1D	109.0	O7—C9—C8	111.8 (6)
C2—C1—H1D	109.0	C10—C9—C8	109.5 (6)
N1—C2—C3	112.4 (6)	O7—C9—H9A	109.0
N1—C2—C1	109.9 (6)	C10—C9—H9A	109.0
C3—C2—C1	110.2 (6)	C8—C9—H9A	109.0
N1—C2—H2A	108.1	O8—C10—C9	107.6 (6)
C3—C2—H2A	108.1	O8—C10—C11	112.3 (6)
C1—C2—H2A	108.1	C9—C10—C11	107.9 (6)
O2—C3—C4	111.9 (7)	O8—C10—H10	109.7
O2—C3—C2	106.9 (6)	C9—C10—H10	109.7
C4—C3—C2	108.6 (6)	C11—C10—H10	109.7
O2—C3—H3A	109.8	O10—C11—C12	106.9 (6)
C4—C3—H3A	109.8	O10—C11—C10	110.3 (6)
C2—C3—H3A	109.8	C12—C11—C10	111.7 (6)
O5—C4—C3	110.8 (6)	O10—C11—H11	109.3
O5—C4—C5	106.7 (6)	C12—C11—H11	109.3
C3—C4—C5	111.6 (6)	C10—C11—H11	109.3
O5—C4—H4	109.3	O9—C12—C11	113.2 (6)
C3—C4—H4	109.3	O9—C12—H12A	108.9
C5—C4—H4	109.3	C11—C12—H12A	108.9
O4—C5—C6	106.8 (6)	O9—C12—H12B	108.9
O4—C5—C4	108.6 (6)	C11—C12—H12B	108.9
C6—C5—C4	112.5 (7)	H12A—C12—H12B	107.7
O4—C5—H5	109.6

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
O1—H1···Cl1	0.83 (5)	2.28 (6)	3.075 (6)	163 (9)
O2—H2···O10	0.80 (5)	1.98 (6)	2.743 (7)	159 (8)
O3—H3···Cl1ⁱ	0.82 (5)	2.31 (6)	3.130 (7)	172 (9)
O6—H6···O9ⁱⁱ	0.82 (5)	1.84 (6)	2.654 (8)	171 (9)
O7—H7···O2ⁱⁱⁱ	0.81 (5)	1.92 (6)	2.697 (8)	158 (9)
O8—H8···Cl1^iv	0.78 (5)	2.32 (6)	3.080 (5)	166 (8)
O9—H9···O6^v	0.83 (5)	1.88 (5)	2.707 (8)	178 (9)
N1—H1A···O1W	0.90 (4)	1.96 (5)	2.819 (9)	159 (7)
N1—H1B···O7^vi	0.90 (4)	2.26 (7)	2.862 (8)	124 (6)
N1—H1B···O8^vi	0.90 (4)	2.16 (6)	2.922 (8)	142 (7)
N1—H1C···O1	0.91 (4)	2.34 (8)	2.787 (9)	110 (6)
N1—H1C···O1W^vii	0.91 (4)	2.35 (6)	3.162 (11)	149 (7)
O1W—H1WA···O3^viii	0.90 (6)	1.85 (7)	2.746 (8)	170 (10)
O1W—H1WB···Cl1^ix	0.89 (6)	2.50 (7)	3.335 (7)	156 (9)

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

Conformational features (Å, °) of the glycosidic bond in (I) and related disaccharide structures with the Gal-β1→4-Glc link top

Sugar	Tautomer, conformation	τ	Φ	Ψ	Intramolecular contacts around glycosidic bond (O···H; O···O; O···H—O)
Gal-β1→4-GlcNH₃⁺Cl^-·H₂O (I)^a	α-pyranose, ⁴C₁	116.0	-95.2	+90.7	O10···H—O2 (1.98; 2.743; 159) O5···H-O2 (2.64; 2.964; 106)
Gal-β1→4-GlcNHCOCH₃·H₂O (N-acetyllactosamine, LacNAc·H₂O)^b	α-pyranose, ⁴C₁^b	116.3	-88.1	+97.8	O10···H-O2 (1.98; 2.787; 139) O5···H—O6 (2.40; 2.868; 122)
LacNAc/ toad galectin^c	α-pyranose, ⁴C₁	118.2; 113.6	-66.9; -67.8	+132.4; +132.6	Not reported
LacNAc calculations^d	α-pyranose, ⁴C₁^d	117.1	-75	+135	O10···H—O2
Gal-β1→4-Glc·H₂O (α-lactose)^e	α-pyranose, ⁴C₁	116.9	-93.4	+95.9	O10···H—O2 (2.02; 2.819; 159) O5···H—O2 (2.65; 2.992; 106)
Gal-β1→4-Glc (β-lactose)^f	β-pyranose, ⁴C₁	116.5	-76.3	+106.4	O10···H—O2 (n.d.; 2.707; 101)
Gal-β1→4-GlcNHCOCH₃·2H₂O (N-acetyllactosylamine)^g	β-pyranose, ⁴C₁	117.4	-89.3	+81.5	O10···H—O2 (2.06; 2.767; 144) O9···H—O2 (2.45; 3.126; 141)

Notes: (a) This work; (b) Longchambon et al. (1981); (c) Bianchet et al. (2000); (d) Imberty et al. (1991); (e) Smith et al. (2005); (f) Hirotsu & Shimada (1974); (g) Lakshmanan et al. (2001).

Additional D—H···A contacts (Å, °) top

D—H···A	D—H	H···A	D···A	D—H···A
O2—H2···O5	0.80 (7)	2.64 (8)	2.964 (8)	106 (6)
N1—H1B···O2	0.90 (6)	2.55 (7)	2.855 (9)	101 (5)
O7—H7···O6	0.81 (8)	2.63 (8)	2.847 (8)	97 (8)
C2—H2A···O1ⁱ	0.98	2.34	3.199 (10)	146
C9—H9A···O8ⁱ	0.98	2.58	3.309 (9)	132
C10—H10···Cl1ⁱⁱ	0.98	2.82	3.741 (9)	157

Symmetry codes: (i) x + 1, y, z; (ii) x + 1, y, z - 1.

Funding information

Funding for this research was provided by: University of Missouri, Agriculture Experiment Station Chemical Laboratories; National Institute of Food and Agriculture (grant No. Hatch 1023929).

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