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The crystal structure of the title compound, C14H25NO11·2H2O, has been determined. The glucose and galactose residues are in a 4C1 conformation. The N-acetyl group has a Z-anti conformation.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270101004796/de1160sup1.cif
Contains datablocks global, I

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S0108270101004796/de1160Isup2.hkl
Contains datablock I

CCDC reference: 169938

Comment top

The oligosaccharide components of glycoproteins play an important role in various biological recognition processes, such as protein targeting and cellular recognition (Dwek, 1996). As part of our efforts to unravel the structural aspects of N-glycopeptides, we have reported previously the crystal structures of simple model compounds of the linkage region, viz. β-1-N-acetamido-D-glucopyranose (Sriram et al., 1997) and β-1-N-benzamido-D-glucopyranose (Sriram, Srinivasan et al., 1998), and also β-1-N-acetamido-(2-acetamido-2-deoxy)-D-glucopyranose and β-1-N-benzamido-(2-acetamido-2-deoxy)-D-glucopyranose (Sriram, Lakshmanan et al., 1998). For the present study, the title compound (I) was chosen as a disaccharide model.

The structure of (I) together with atom-numbering scheme is shown in Fig. 1 (PLATON; Spek, 2000). Selected geometrical parameters are listed in Table 1. Both the glucose and galactose residues adopt a 4C1 conformation. The three-dimensional structure of the disaccharide is determined by the glycosidic torsion angles ϕ(C14—O14—C21—O25) and ψ(C21—O14—C14—C15), the values of which are -89.3 (2) and -157.84 (18)°, respectively. These values compare well with those reported in the literature for the related disaccharides methyl β-lactoside (Stenutz et al., 1999) and methyl β-cellobioside (Ham & Williams, 1970) (Table 2). While there is a good agreement of ϕ with the corresponding value of N-acetyl a-lactosamine (-88.1°) and α-lactose (-92.60°), the value of ψ differs by about 15–20°. The exocyclic primary hydroxyl group adopts a gg and gt conformation in glucose and galactose residues, respectively. This is indicated by ω(O15—C15—C16—O16) being -59.3 (2)° and ω'(O25—C25—C26—O26) being 58.3 (2)°. In the lactose derivatives shown in Table 3, the glucose hydroxymethyl group is in a gt conformation, except for the cases of methyl β-lactoside and N-acetyl α-lactosamine.

As is observed in the other model compounds reported by us and also in GlcNAc-Asn (Delbaere, 1974), the N-acetyl group has a Z-anti conformation, as shown by the torsion angles C11—N1—C1—C2 [173.0 (2)°] and C1—N1—C11—O15 [-101.1 (3)°]. When the molecule exists in a fully extended conformation, the angles C14—O14—C21—O25 and C21—O14—C14—C13 should be close to -110 and 110°, respectively (Fries et al.,1971). However, probably to accomadate the intramolecular hydrogen bond observed in most of the β(1()4)-linked disaccharides between the O25 and O13 atoms, compound (I) undergoes a symmetrical twist about the bridge glycosidic bonds, with the two torsion angles being -89.3 (2) and 81.5 (3)°, respectively. Both hydrate molecules are extensively involved in a network of hydrogen bonds which fall into two categories: (i) a finite chain of hydrogen bonds starting from O24—H and ending at O25, passing through the two water molecules, and (ii) a second finite chain of hydrogen bonds starting at O24—H and ending at O17, with a hydrogen bond also between N1—H and O17. An infinite chain of hydrogen bonds alternates between O23 and O26 (Table 2).

Experimental top

The title compound was prepared by peracetylation followed by selective de-O-acetylation of β-lactosylamine. Lactose dissolved in a saturated aqueous ammonium bicarbonate solution was allowed to react for five days to obtain β-lactosylamine (Likhosherstov et al., 1986). The amine obtained after lyophilization was extracted in methanol and treated with pyridine and acetic anhydride to obtain the peracetylated product, which on subsequent de-O-acetylation with sodium methoxide gave compound (I) in an overall yield of 30% [m.p. 515 K (decoposition); literature: 519 521 K (Kuhn & Kruger, 1954)]. Crystals suitable for analysis were obtained from an aqueous methanol solution by slow evaporation.

Refinement top

H atoms were located from the difference Fourier map and were refined isotropically.

Computing details top

Data collection: CAD-4 Software (Enraf-Nonius, 1989); cell refinement: CAD-4 Software; data reduction: CAD-4 Software; program(s) used to solve structure: SHELXS97 (Sheldrick, 1990); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: PLATON (Spek, 2000); software used to prepare material for publication: SHELXL97.

Figures top
[Figure 1] Fig. 1. The structure of (I) showing the atom-numbering scheme and displacement ellipsoids at the 30% probability level for C and O atoms. H atoms are shown as spheres of arbitrary radii.
β-1-N-Acetamido-(4-O-β-D-galactopyranosyl)-D-glucopyranose dihydrate top
Crystal data top
C14H25NO11·2H2OF(000) = 224
Mr = 419.38Dx = 1.482 Mg m3
Triclinic, P1Melting point: 242°C (dec.) K
a = 4.860 (6) ÅMo Kα radiation, λ = 0.71073 Å
b = 7.603 (10) ÅCell parameters from 25 reflections
c = 13.242 (2) Åθ = 15–25°
α = 85.47 (1)°µ = 0.13 mm1
β = 84.06 (2)°T = 293 K
γ = 75.19 (1)°Prismatic, colourless
V = 469.8 (9) Å30.35 × 0.35 × 0.34 mm
Z = 1
Data collection top
Enraf-Nonius CAD-4
diffractometer
1592 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tubeRint = 0.000
Graphite monochromatorθmax = 25.0°, θmin = 2.8°
ω/2θ scansh = 55
Absorption correction: ψ scan
MolEN (Fair, 1990)
k = 88
Tmin = 0.92, Tmax = 0.96l = 015
1650 measured reflectionsStandard reflections: TWO; every 60 min
1650 independent reflections intensity decay: 3%
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.027Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.072H atoms treated by a mixture of independent and constrained refinement
S = 1.04 w = 1/[σ2(Fo2) + (0.0507P)2 + 0.0587P]
where P = (Fo2 + 2Fc2)/3
1650 reflections(Δ/σ)max < 0.001
274 parametersΔρmax = 0.20 e Å3
7 restraintsΔρmin = 0.23 e Å3
Crystal data top
C14H25NO11·2H2Oγ = 75.19 (1)°
Mr = 419.38V = 469.8 (9) Å3
Triclinic, P1Z = 1
a = 4.860 (6) ÅMo Kα radiation
b = 7.603 (10) ŵ = 0.13 mm1
c = 13.242 (2) ÅT = 293 K
α = 85.47 (1)°0.35 × 0.35 × 0.34 mm
β = 84.06 (2)°
Data collection top
Enraf-Nonius CAD-4
diffractometer
1592 reflections with I > 2σ(I)
Absorption correction: ψ scan
MolEN (Fair, 1990)
Rint = 0.000
Tmin = 0.92, Tmax = 0.96Standard reflections: TWO; every 60 min
1650 measured reflections intensity decay: 3%
1650 independent reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0277 restraints
wR(F2) = 0.072H atoms treated by a mixture of independent and constrained refinement
S = 1.04Δρmax = 0.20 e Å3
1650 reflectionsΔρmin = 0.23 e Å3
274 parameters
Special details top

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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/UeqOcc. (<1)
O120.1888 (4)1.1234 (2)0.60493 (14)0.0373 (4)
H120.12191.12600.55030.056*
O130.5483 (4)0.8945 (2)0.45750 (13)0.0376 (4)
H130.53030.85120.40450.056*
O140.4999 (3)0.5001 (2)0.49993 (12)0.0286 (4)
O150.4007 (3)0.6882 (2)0.74663 (12)0.0280 (4)
O160.8414 (4)0.3772 (2)0.72945 (15)0.0376 (4)
H160.95560.30800.69150.056*
O170.2337 (4)0.9611 (3)0.86653 (17)0.0475 (5)
O220.8527 (4)0.1579 (2)0.44883 (14)0.0355 (4)
H220.77920.07140.45450.053*
O230.9578 (4)0.0949 (2)0.23720 (15)0.0352 (4)
H230.80760.07170.22700.053*
O240.4932 (4)0.3828 (2)0.18127 (13)0.0325 (4)
H240.45660.41360.12240.049*
O250.5519 (3)0.6114 (2)0.33784 (13)0.0297 (4)
O260.5246 (4)0.9281 (2)0.22159 (18)0.0459 (5)
H260.35420.97820.23140.069*
N10.2131 (4)0.9707 (3)0.80935 (16)0.0283 (4)
H10.35531.01490.81710.034*
C10.0124 (5)1.0039 (3)0.87794 (19)0.0303 (5)
C20.0176 (7)1.0977 (5)0.9694 (2)0.0500 (8)
H2A0.20461.11970.96490.075*0.50
H2B0.00831.02231.02940.075*0.50
H2C0.12411.21170.97270.075*0.50
H2D0.15641.11611.01310.075*0.50
H2E0.05641.21350.94860.075*0.50
H2F0.17231.02411.00530.075*0.50
C110.2283 (5)0.8644 (3)0.72323 (17)0.0252 (5)
H110.03610.85560.71220.030*
C120.3589 (5)0.9458 (3)0.62729 (18)0.0261 (5)
H12A0.54940.95560.64000.031*
C130.3908 (5)0.8220 (3)0.53948 (18)0.0267 (5)
H13A0.20060.82700.51910.032*
C140.5358 (5)0.6246 (3)0.57024 (17)0.0240 (5)
H140.73990.61230.57480.029*
C150.4023 (5)0.5638 (3)0.67138 (18)0.0257 (5)
H150.20460.56260.66330.031*
C160.5586 (5)0.3770 (3)0.71122 (19)0.0308 (5)
H16A0.45770.34320.77390.037*
H16B0.56430.28790.66200.037*
C210.6823 (5)0.4790 (3)0.41185 (17)0.0255 (5)
H210.86790.49750.42430.031*
C220.7188 (5)0.2884 (3)0.37536 (18)0.0248 (5)
H22A0.53100.26950.36640.030*
C230.8990 (5)0.2733 (3)0.27375 (19)0.0269 (5)
H23A1.08230.29710.28470.032*
C240.7566 (5)0.4191 (3)0.19753 (17)0.0261 (5)
H24A0.87810.41280.13340.031*
C250.7163 (5)0.6050 (3)0.24124 (18)0.0273 (5)
H250.90400.62390.25040.033*
C260.5575 (6)0.7605 (3)0.1752 (2)0.0351 (6)
H26A0.66240.76360.10890.042*
H26B0.37120.74300.16580.042*
O10.8563 (5)0.5730 (3)0.89680 (18)0.0480 (5)
H1110.803 (10)0.681 (5)0.879 (4)0.079 (7)*
H1120.852 (10)0.526 (6)0.839 (3)0.079 (7)*
O20.3447 (7)0.5179 (7)0.9965 (2)0.1106 (16)
H2110.207 (9)0.533 (7)0.959 (4)0.079 (7)*
H2120.449 (10)0.572 (6)0.961 (3)0.079 (7)*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
O120.0510 (11)0.0211 (8)0.0357 (9)0.0040 (7)0.0138 (8)0.0071 (7)
O130.0639 (12)0.0256 (9)0.0268 (8)0.0191 (8)0.0016 (8)0.0031 (7)
O140.0364 (9)0.0248 (8)0.0269 (8)0.0113 (7)0.0018 (6)0.0083 (6)
O150.0334 (9)0.0218 (8)0.0271 (8)0.0018 (6)0.0053 (7)0.0037 (6)
O160.0353 (9)0.0293 (9)0.0459 (10)0.0009 (7)0.0099 (8)0.0097 (8)
O170.0294 (9)0.0588 (13)0.0570 (12)0.0132 (9)0.0034 (8)0.0208 (10)
O220.0470 (10)0.0233 (9)0.0375 (9)0.0064 (7)0.0180 (8)0.0018 (7)
O230.0360 (9)0.0196 (8)0.0486 (10)0.0009 (7)0.0042 (8)0.0130 (7)
O240.0362 (9)0.0337 (9)0.0312 (9)0.0139 (7)0.0082 (7)0.0000 (7)
O250.0371 (9)0.0198 (8)0.0287 (8)0.0008 (7)0.0001 (7)0.0043 (6)
O260.0398 (11)0.0190 (8)0.0786 (15)0.0039 (7)0.0078 (10)0.0079 (9)
N10.0275 (9)0.0273 (10)0.0317 (10)0.0060 (8)0.0054 (8)0.0092 (8)
C10.0296 (13)0.0267 (12)0.0324 (12)0.0026 (9)0.0020 (10)0.0045 (9)
C20.0557 (19)0.0562 (18)0.0409 (15)0.0168 (15)0.0051 (13)0.0220 (14)
C110.0230 (10)0.0245 (11)0.0274 (11)0.0023 (8)0.0049 (9)0.0065 (9)
C120.0277 (11)0.0182 (11)0.0319 (12)0.0013 (9)0.0077 (9)0.0050 (9)
C130.0316 (12)0.0230 (11)0.0259 (11)0.0073 (9)0.0039 (9)0.0012 (9)
C140.0263 (11)0.0199 (11)0.0263 (11)0.0057 (8)0.0016 (9)0.0056 (9)
C150.0261 (11)0.0235 (12)0.0289 (11)0.0076 (9)0.0027 (9)0.0044 (9)
C160.0390 (13)0.0220 (11)0.0320 (12)0.0083 (10)0.0040 (10)0.0018 (9)
C210.0283 (11)0.0216 (11)0.0268 (11)0.0060 (9)0.0026 (9)0.0034 (9)
C220.0283 (11)0.0183 (11)0.0284 (11)0.0047 (9)0.0080 (9)0.0018 (8)
C230.0258 (11)0.0187 (11)0.0362 (12)0.0027 (9)0.0037 (9)0.0096 (9)
C240.0282 (11)0.0229 (11)0.0275 (12)0.0072 (9)0.0009 (9)0.0035 (9)
C250.0308 (12)0.0218 (11)0.0297 (12)0.0081 (9)0.0000 (9)0.0028 (9)
C260.0431 (14)0.0239 (12)0.0370 (13)0.0070 (10)0.0007 (11)0.0014 (10)
O10.0493 (12)0.0513 (13)0.0468 (12)0.0157 (10)0.0135 (10)0.0002 (10)
O20.0738 (19)0.224 (5)0.0530 (16)0.081 (3)0.0322 (14)0.056 (2)
Geometric parameters (Å, º) top
O12—C121.418 (3)C2—H2F0.9600
O12—H120.8200C11—C121.520 (3)
O13—C131.421 (3)C11—H110.9800
O13—H130.8200C12—C131.524 (3)
O14—C211.384 (3)C12—H12A0.9800
O14—C141.432 (3)C13—C141.529 (4)
O15—C111.417 (3)C13—H13A0.9800
O15—C151.425 (3)C14—C151.518 (3)
O16—C161.421 (3)C14—H140.9800
O16—H160.8200C15—C161.512 (4)
O17—C11.227 (4)C15—H150.9800
O22—C221.415 (3)C16—H16A0.9700
O22—H220.8200C16—H16B0.9700
O23—C231.425 (3)C21—C221.525 (3)
O23—H230.8200C21—H210.9800
O24—C241.417 (3)C22—C231.523 (3)
O24—H240.8200C22—H22A0.9800
O25—C211.422 (3)C23—C241.517 (3)
O25—C251.434 (3)C23—H23A0.9800
O26—C261.423 (3)C24—C251.528 (3)
O26—H260.8200C24—H24A0.9800
N1—C11.334 (3)C25—C261.506 (4)
N1—C111.434 (3)C25—H250.9800
N1—H10.8600C26—H26A0.9700
C1—C21.491 (4)C26—H26B0.9700
C2—H2A0.9600O1—H1110.82 (4)
C2—H2B0.9600O1—H1120.88 (4)
C2—H2C0.9600O2—H2110.85 (4)
C2—H2D0.9600O2—H2120.82 (4)
C2—H2E0.9600
C12—O12—H12109.5O14—C14—C13111.98 (19)
C13—O13—H13109.5C15—C14—C13111.33 (19)
C21—O14—C14117.37 (18)O14—C14—H14109.6
C11—O15—C15111.98 (18)C15—C14—H14109.6
C16—O16—H16109.5C13—C14—H14109.6
C22—O22—H22109.5O15—C15—C16107.04 (19)
C23—O23—H23109.5O15—C15—C14110.06 (18)
C24—O24—H24109.5C16—C15—C14113.54 (19)
C21—O25—C25113.61 (18)O15—C15—H15108.7
C26—O26—H26109.5C16—C15—H15108.7
C1—N1—C11122.7 (2)C14—C15—H15108.7
C1—N1—H1118.6O16—C16—C15110.1 (2)
C11—N1—H1118.6O16—C16—H16A109.6
O17—C1—N1122.1 (2)C15—C16—H16A109.6
O17—C1—C2121.5 (2)O16—C16—H16B109.6
N1—C1—C2116.3 (2)C15—C16—H16B109.6
C1—C2—H2A109.5H16A—C16—H16B108.2
C1—C2—H2B109.5O14—C21—O25107.14 (19)
H2A—C2—H2B109.5O14—C21—C22109.15 (19)
C1—C2—H2C109.5O25—C21—C22109.68 (19)
H2A—C2—H2C109.5O14—C21—H21110.3
H2B—C2—H2C109.5O25—C21—H21110.3
C1—C2—H2D109.5C22—C21—H21110.3
H2A—C2—H2D141.1O22—C22—C23111.0 (2)
H2B—C2—H2D56.3O22—C22—C21109.16 (19)
H2C—C2—H2D56.3C23—C22—C21108.39 (19)
C1—C2—H2E109.5O22—C22—H22A109.4
H2A—C2—H2E56.3C23—C22—H22A109.4
H2B—C2—H2E141.1C21—C22—H22A109.4
H2C—C2—H2E56.3O23—C23—C24112.3 (2)
H2D—C2—H2E109.5O23—C23—C22111.9 (2)
C1—C2—H2F109.5C24—C23—C22109.98 (19)
H2A—C2—H2F56.3O23—C23—H23A107.5
H2B—C2—H2F56.3C24—C23—H23A107.5
H2C—C2—H2F141.1C22—C23—H23A107.5
H2D—C2—H2F109.5O24—C24—C23107.2 (2)
H2E—C2—H2F109.5O24—C24—C25112.3 (2)
O15—C11—N1107.11 (19)C23—C24—C25108.3 (2)
O15—C11—C12109.43 (19)O24—C24—H24A109.7
N1—C11—C12112.01 (19)C23—C24—H24A109.7
O15—C11—H11109.4C25—C24—H24A109.7
N1—C11—H11109.4O25—C25—C26106.4 (2)
C12—C11—H11109.4O25—C25—C24109.92 (18)
O12—C12—C11109.4 (2)C26—C25—C24113.2 (2)
O12—C12—C13112.00 (19)O25—C25—H25109.1
C11—C12—C13110.36 (19)C26—C25—H25109.1
O12—C12—H12A108.3C24—C25—H25109.1
C11—C12—H12A108.3O26—C26—C25109.9 (2)
C13—C12—H12A108.3O26—C26—H26A109.7
O13—C13—C12106.64 (19)C25—C26—H26A109.7
O13—C13—C14112.3 (2)O26—C26—H26B109.7
C12—C13—C14111.35 (19)C25—C26—H26B109.7
O13—C13—H13A108.8H26A—C26—H26B108.2
C12—C13—H13A108.8H111—O1—H11299 (5)
C14—C13—H13A108.8H211—O2—H212101 (4)
O14—C14—C15104.55 (18)
C11—N1—C1—O177.5 (4)O15—C15—C16—O1659.3 (2)
C11—N1—C1—C2173.0 (2)C14—C15—C16—O1662.3 (3)
C15—O15—C11—N1172.79 (17)C14—O14—C21—O2589.3 (2)
C15—O15—C11—C1265.6 (2)C14—O14—C21—C22151.96 (19)
C1—N1—C11—O15101.1 (3)C25—O25—C21—O14179.43 (17)
C1—N1—C11—C12139.0 (2)C25—O25—C21—C2261.1 (2)
O15—C11—C12—O12179.01 (18)O14—C21—C22—O2263.8 (2)
N1—C11—C12—O1260.4 (2)O25—C21—C22—O22179.09 (18)
O15—C11—C12—C1357.4 (2)O14—C21—C22—C23175.18 (18)
N1—C11—C12—C13175.97 (19)O25—C21—C22—C2358.1 (2)
O12—C12—C13—O1365.7 (3)O22—C22—C23—O2356.6 (3)
C11—C12—C13—O13172.24 (18)C21—C22—C23—O23176.47 (18)
O12—C12—C13—C14171.50 (19)O22—C22—C23—C24177.82 (18)
C11—C12—C13—C1449.4 (2)C21—C22—C23—C2457.9 (2)
C21—O14—C14—C15157.80 (18)O23—C23—C24—O2461.4 (2)
C21—O14—C14—C1381.5 (3)C22—C23—C24—O2463.9 (2)
O13—C13—C14—O1476.0 (2)O23—C23—C24—C25177.19 (18)
C12—C13—C14—O14164.44 (18)C22—C23—C24—C2557.5 (2)
O13—C13—C14—C15167.31 (18)C21—O25—C25—C26176.39 (19)
C12—C13—C14—C1547.8 (2)C21—O25—C25—C2460.7 (2)
C11—O15—C15—C16172.56 (18)O24—C24—C25—O2561.0 (2)
C11—O15—C15—C1463.6 (2)C23—C24—C25—O2557.2 (2)
O14—C14—C15—O15174.66 (17)O24—C24—C25—C2657.8 (2)
C13—C14—C15—O1553.6 (2)C23—C24—C25—C26176.0 (2)
O14—C14—C15—C1665.4 (2)O25—C25—C26—O2658.3 (2)
C13—C14—C15—C16173.51 (19)C24—C25—C26—O26179.1 (2)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O12—H12···O22i0.821.932.721 (3)162
O13—H13···O250.822.062.767 (3)144
O16—H16···O12ii0.821.932.749 (4)172
O22—H22···O13iii0.821.962.767 (4)170
O23—H23···O26iii0.821.972.753 (4)159
O24—H24···O2iv0.821.862.675 (3)171
O26—H26···O23i0.821.902.716 (5)173
N1—H1···O17v0.862.102.849 (4)146
O1—H111···O17v0.82 (4)2.08 (4)2.872 (5)161 (5)
O1—H112···O160.88 (4)1.91 (4)2.782 (3)168 (4)
O2—H211···O1vi0.85 (4)1.91 (4)2.758 (4)170 (5)
O2—H212···O10.82 (4)2.07 (4)2.804 (5)148 (5)
Symmetry codes: (i) x1, y+1, z; (ii) x+1, y1, z; (iii) x, y1, z; (iv) x, y, z1; (v) x+1, y, z; (vi) x1, y, z.

Experimental details

Crystal data
Chemical formulaC14H25NO11·2H2O
Mr419.38
Crystal system, space groupTriclinic, P1
Temperature (K)293
a, b, c (Å)4.860 (6), 7.603 (10), 13.242 (2)
α, β, γ (°)85.47 (1), 84.06 (2), 75.19 (1)
V3)469.8 (9)
Z1
Radiation typeMo Kα
µ (mm1)0.13
Crystal size (mm)0.35 × 0.35 × 0.34
Data collection
DiffractometerEnraf-Nonius CAD-4
diffractometer
Absorption correctionψ scan
MolEN (Fair, 1990)
Tmin, Tmax0.92, 0.96
No. of measured, independent and
observed [I > 2σ(I)] reflections
1650, 1650, 1592
Rint0.000
(sin θ/λ)max1)0.594
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.027, 0.072, 1.04
No. of reflections1650
No. of parameters274
No. of restraints7
H-atom treatmentH atoms treated by a mixture of independent and constrained refinement
Δρmax, Δρmin (e Å3)0.20, 0.23

Computer programs: CAD-4 Software (Enraf-Nonius, 1989), CAD-4 Software, SHELXS97 (Sheldrick, 1990), SHELXL97 (Sheldrick, 1997), PLATON (Spek, 2000), SHELXL97.

Selected geometric parameters (Å, º) top
O14—C211.384 (3)N1—C11.334 (3)
O14—C141.432 (3)N1—C111.434 (3)
O15—C111.417 (3)C15—C161.512 (4)
O25—C211.422 (3)C25—C261.506 (4)
C21—O14—C14117.37 (18)C1—N1—C11122.7 (2)
C11—O15—C15111.98 (18)O15—C11—N1107.11 (19)
C21—O25—C25113.61 (18)
C11—N1—C1—O177.5 (4)C21—O14—C14—C1381.5 (3)
C11—N1—C1—C2173.0 (2)O15—C15—C16—O1659.3 (2)
C1—N1—C11—O15101.1 (3)C14—O14—C21—O2589.3 (2)
C21—O14—C14—C15157.80 (18)O25—C25—C26—O2658.3 (2)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O12—H12···O22i0.821.932.721 (3)161.7
O13—H13···O250.822.062.767 (3)143.9
O16—H16···O12ii0.821.932.749 (4)172.1
O22—H22···O13iii0.821.962.767 (4)170.1
O23—H23···O26iii0.821.972.753 (4)159.0
O24—H24···O2iv0.821.862.675 (3)171.3
O26—H26···O23i0.821.902.716 (5)173.2
N1—H1···O17v0.862.102.849 (4)145.8
O1—H111···O17v0.82 (4)2.08 (4)2.872 (5)161 (5)
O1—H112···O160.88 (4)1.91 (4)2.782 (3)168 (4)
O2—H211···O1vi0.85 (4)1.91 (4)2.758 (4)170 (5)
O2—H212···O10.82 (4)2.07 (4)2.804 (5)148 (5)
Symmetry codes: (i) x1, y+1, z; (ii) x+1, y1, z; (iii) x, y1, z; (iv) x, y, z1; (v) x+1, y, z; (vi) x1, y, z.
Comparison of selected torsional angels of lactosyl acetamide, (I), with those of related disaccharides (°) top
Compoundϕψωω'
Lactosyl acetamide.H2Oa-89.3-157.8-59.558.1
Methyl β-lactoside.CH3OHb-88.4-161.3-54.657.3
Methyl β-cellobioside.CH3OHc-91.1-160.7-55.152.4
β-Lactosed-70.9-131.572.650.5
α-Lactose.H2Oe-92.6-143.063.259.4
N-Acetyl α-lactosamine.H2Of-88.1-139.5-56.066.8
α-Lactose.CaCl2.7H2Og-76.9-136.963.859.8
α-Lactose.CaBr2.7H2Oh-76.0-134.961.962.4
Notes: (a) this report; (b) Stenutz et al. (1999); (c) Ham & Williams (1970); (d) Hiroustu & Shimada (1974); (e) Fries et al. (1971); (f) Longchambon et al. (1981); (g) Cook & Bugg (1973); (h) Bugg (1973).
 

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