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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
CCDC reference: 169938
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.
H atoms were located from the difference Fourier map and were refined
isotropically.
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.
β-1-
N-Acetamido-(4-O-
β-
D-galactopyranosyl)-
D-glucopyranose dihydrate
top
Crystal data top
C14H25NO11·2H2O | F(000) = 224 |
Mr = 419.38 | Dx = 1.482 Mg m−3 |
Triclinic, P1 | Melting point: 242°C (dec.) K |
a = 4.860 (6) Å | Mo Kα radiation, λ = 0.71073 Å |
b = 7.603 (10) Å | Cell parameters from 25 reflections |
c = 13.242 (2) Å | θ = 15–25° |
α = 85.47 (1)° | µ = 0.13 mm−1 |
β = 84.06 (2)° | T = 293 K |
γ = 75.19 (1)° | Prismatic, colourless |
V = 469.8 (9) Å3 | 0.35 × 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 tube | Rint = 0.000 |
Graphite monochromator | θmax = 25.0°, θmin = 2.8° |
ω/2θ scans | h = −5→5 |
Absorption correction: ψ scan MolEN (Fair, 1990) | k = −8→8 |
Tmin = 0.92, Tmax = 0.96 | l = 0→15 |
1650 measured reflections | Standard reflections: TWO; every 60 min |
1650 independent reflections | intensity decay: 3% |
Refinement top
Refinement on F2 | Primary atom site location: structure-invariant direct methods |
Least-squares matrix: full | Secondary atom site location: difference Fourier map |
R[F2 > 2σ(F2)] = 0.027 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.072 | H 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 parameters | Δρmax = 0.20 e Å−3 |
7 restraints | Δρmin = −0.23 e Å−3 |
Crystal data top
C14H25NO11·2H2O | γ = 75.19 (1)° |
Mr = 419.38 | V = 469.8 (9) Å3 |
Triclinic, P1 | Z = 1 |
a = 4.860 (6) Å | Mo Kα radiation |
b = 7.603 (10) Å | µ = 0.13 mm−1 |
c = 13.242 (2) Å | T = 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 = 0.96 | Standard reflections: TWO; every 60 min |
1650 measured reflections | intensity decay: 3% |
1650 independent reflections | |
Refinement top
R[F2 > 2σ(F2)] = 0.027 | 7 restraints |
wR(F2) = 0.072 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.04 | Δρmax = 0.20 e Å−3 |
1650 reflections | Δρmin = −0.23 e Å−3 |
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 | x | y | z | Uiso*/Ueq | Occ. (<1) |
O12 | 0.1888 (4) | 1.1234 (2) | 0.60493 (14) | 0.0373 (4) | |
H12 | 0.1219 | 1.1260 | 0.5503 | 0.056* | |
O13 | 0.5483 (4) | 0.8945 (2) | 0.45750 (13) | 0.0376 (4) | |
H13 | 0.5303 | 0.8512 | 0.4045 | 0.056* | |
O14 | 0.4999 (3) | 0.5001 (2) | 0.49993 (12) | 0.0286 (4) | |
O15 | 0.4007 (3) | 0.6882 (2) | 0.74663 (12) | 0.0280 (4) | |
O16 | 0.8414 (4) | 0.3772 (2) | 0.72945 (15) | 0.0376 (4) | |
H16 | 0.9556 | 0.3080 | 0.6915 | 0.056* | |
O17 | −0.2337 (4) | 0.9611 (3) | 0.86653 (17) | 0.0475 (5) | |
O22 | 0.8527 (4) | 0.1579 (2) | 0.44883 (14) | 0.0355 (4) | |
H22 | 0.7792 | 0.0714 | 0.4545 | 0.053* | |
O23 | 0.9578 (4) | 0.0949 (2) | 0.23720 (15) | 0.0352 (4) | |
H23 | 0.8076 | 0.0717 | 0.2270 | 0.053* | |
O24 | 0.4932 (4) | 0.3828 (2) | 0.18127 (13) | 0.0325 (4) | |
H24 | 0.4566 | 0.4136 | 0.1224 | 0.049* | |
O25 | 0.5519 (3) | 0.6114 (2) | 0.33784 (13) | 0.0297 (4) | |
O26 | 0.5246 (4) | 0.9281 (2) | 0.22159 (18) | 0.0459 (5) | |
H26 | 0.3542 | 0.9782 | 0.2314 | 0.069* | |
N1 | 0.2131 (4) | 0.9707 (3) | 0.80935 (16) | 0.0283 (4) | |
H1 | 0.3553 | 1.0149 | 0.8171 | 0.034* | |
C1 | −0.0124 (5) | 1.0039 (3) | 0.87794 (19) | 0.0303 (5) | |
C2 | 0.0176 (7) | 1.0977 (5) | 0.9694 (2) | 0.0500 (8) | |
H2A | 0.2046 | 1.1197 | 0.9649 | 0.075* | 0.50 |
H2B | −0.0083 | 1.0223 | 1.0294 | 0.075* | 0.50 |
H2C | −0.1241 | 1.2117 | 0.9727 | 0.075* | 0.50 |
H2D | −0.1564 | 1.1161 | 1.0131 | 0.075* | 0.50 |
H2E | 0.0564 | 1.2135 | 0.9486 | 0.075* | 0.50 |
H2F | 0.1723 | 1.0241 | 1.0053 | 0.075* | 0.50 |
C11 | 0.2283 (5) | 0.8644 (3) | 0.72323 (17) | 0.0252 (5) | |
H11 | 0.0361 | 0.8556 | 0.7122 | 0.030* | |
C12 | 0.3589 (5) | 0.9458 (3) | 0.62729 (18) | 0.0261 (5) | |
H12A | 0.5494 | 0.9556 | 0.6400 | 0.031* | |
C13 | 0.3908 (5) | 0.8220 (3) | 0.53948 (18) | 0.0267 (5) | |
H13A | 0.2006 | 0.8270 | 0.5191 | 0.032* | |
C14 | 0.5358 (5) | 0.6246 (3) | 0.57024 (17) | 0.0240 (5) | |
H14 | 0.7399 | 0.6123 | 0.5748 | 0.029* | |
C15 | 0.4023 (5) | 0.5638 (3) | 0.67138 (18) | 0.0257 (5) | |
H15 | 0.2046 | 0.5626 | 0.6633 | 0.031* | |
C16 | 0.5586 (5) | 0.3770 (3) | 0.71122 (19) | 0.0308 (5) | |
H16A | 0.4577 | 0.3432 | 0.7739 | 0.037* | |
H16B | 0.5643 | 0.2879 | 0.6620 | 0.037* | |
C21 | 0.6823 (5) | 0.4790 (3) | 0.41185 (17) | 0.0255 (5) | |
H21 | 0.8679 | 0.4975 | 0.4243 | 0.031* | |
C22 | 0.7188 (5) | 0.2884 (3) | 0.37536 (18) | 0.0248 (5) | |
H22A | 0.5310 | 0.2695 | 0.3664 | 0.030* | |
C23 | 0.8990 (5) | 0.2733 (3) | 0.27375 (19) | 0.0269 (5) | |
H23A | 1.0823 | 0.2971 | 0.2847 | 0.032* | |
C24 | 0.7566 (5) | 0.4191 (3) | 0.19753 (17) | 0.0261 (5) | |
H24A | 0.8781 | 0.4128 | 0.1334 | 0.031* | |
C25 | 0.7163 (5) | 0.6050 (3) | 0.24124 (18) | 0.0273 (5) | |
H25 | 0.9040 | 0.6239 | 0.2504 | 0.033* | |
C26 | 0.5575 (6) | 0.7605 (3) | 0.1752 (2) | 0.0351 (6) | |
H26A | 0.6624 | 0.7636 | 0.1089 | 0.042* | |
H26B | 0.3712 | 0.7430 | 0.1658 | 0.042* | |
O1 | 0.8563 (5) | 0.5730 (3) | 0.89680 (18) | 0.0480 (5) | |
H111 | 0.803 (10) | 0.681 (5) | 0.879 (4) | 0.079 (7)* | |
H112 | 0.852 (10) | 0.526 (6) | 0.839 (3) | 0.079 (7)* | |
O2 | 0.3447 (7) | 0.5179 (7) | 0.9965 (2) | 0.1106 (16) | |
H211 | 0.207 (9) | 0.533 (7) | 0.959 (4) | 0.079 (7)* | |
H212 | 0.449 (10) | 0.572 (6) | 0.961 (3) | 0.079 (7)* | |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
O12 | 0.0510 (11) | 0.0211 (8) | 0.0357 (9) | 0.0040 (7) | −0.0138 (8) | −0.0071 (7) |
O13 | 0.0639 (12) | 0.0256 (9) | 0.0268 (8) | −0.0191 (8) | 0.0016 (8) | −0.0031 (7) |
O14 | 0.0364 (9) | 0.0248 (8) | 0.0269 (8) | −0.0113 (7) | 0.0018 (6) | −0.0083 (6) |
O15 | 0.0334 (9) | 0.0218 (8) | 0.0271 (8) | −0.0018 (6) | −0.0053 (7) | −0.0037 (6) |
O16 | 0.0353 (9) | 0.0293 (9) | 0.0459 (10) | 0.0009 (7) | −0.0099 (8) | −0.0097 (8) |
O17 | 0.0294 (9) | 0.0588 (13) | 0.0570 (12) | −0.0132 (9) | 0.0034 (8) | −0.0208 (10) |
O22 | 0.0470 (10) | 0.0233 (9) | 0.0375 (9) | −0.0064 (7) | −0.0180 (8) | 0.0018 (7) |
O23 | 0.0360 (9) | 0.0196 (8) | 0.0486 (10) | −0.0009 (7) | −0.0042 (8) | −0.0130 (7) |
O24 | 0.0362 (9) | 0.0337 (9) | 0.0312 (9) | −0.0139 (7) | −0.0082 (7) | 0.0000 (7) |
O25 | 0.0371 (9) | 0.0198 (8) | 0.0287 (8) | −0.0008 (7) | 0.0001 (7) | −0.0043 (6) |
O26 | 0.0398 (11) | 0.0190 (8) | 0.0786 (15) | −0.0039 (7) | −0.0078 (10) | −0.0079 (9) |
N1 | 0.0275 (9) | 0.0273 (10) | 0.0317 (10) | −0.0060 (8) | −0.0054 (8) | −0.0092 (8) |
C1 | 0.0296 (13) | 0.0267 (12) | 0.0324 (12) | −0.0026 (9) | −0.0020 (10) | −0.0045 (9) |
C2 | 0.0557 (19) | 0.0562 (18) | 0.0409 (15) | −0.0168 (15) | 0.0051 (13) | −0.0220 (14) |
C11 | 0.0230 (10) | 0.0245 (11) | 0.0274 (11) | −0.0023 (8) | −0.0049 (9) | −0.0065 (9) |
C12 | 0.0277 (11) | 0.0182 (11) | 0.0319 (12) | −0.0013 (9) | −0.0077 (9) | −0.0050 (9) |
C13 | 0.0316 (12) | 0.0230 (11) | 0.0259 (11) | −0.0073 (9) | −0.0039 (9) | −0.0012 (9) |
C14 | 0.0263 (11) | 0.0199 (11) | 0.0263 (11) | −0.0057 (8) | −0.0016 (9) | −0.0056 (9) |
C15 | 0.0261 (11) | 0.0235 (12) | 0.0289 (11) | −0.0076 (9) | −0.0027 (9) | −0.0044 (9) |
C16 | 0.0390 (13) | 0.0220 (11) | 0.0320 (12) | −0.0083 (10) | −0.0040 (10) | −0.0018 (9) |
C21 | 0.0283 (11) | 0.0216 (11) | 0.0268 (11) | −0.0060 (9) | −0.0026 (9) | −0.0034 (9) |
C22 | 0.0283 (11) | 0.0183 (11) | 0.0284 (11) | −0.0047 (9) | −0.0080 (9) | −0.0018 (8) |
C23 | 0.0258 (11) | 0.0187 (11) | 0.0362 (12) | −0.0027 (9) | −0.0037 (9) | −0.0096 (9) |
C24 | 0.0282 (11) | 0.0229 (11) | 0.0275 (12) | −0.0072 (9) | 0.0009 (9) | −0.0035 (9) |
C25 | 0.0308 (12) | 0.0218 (11) | 0.0297 (12) | −0.0081 (9) | 0.0000 (9) | −0.0028 (9) |
C26 | 0.0431 (14) | 0.0239 (12) | 0.0370 (13) | −0.0070 (10) | −0.0007 (11) | −0.0014 (10) |
O1 | 0.0493 (12) | 0.0513 (13) | 0.0468 (12) | −0.0157 (10) | −0.0135 (10) | −0.0002 (10) |
O2 | 0.0738 (19) | 0.224 (5) | 0.0530 (16) | −0.081 (3) | −0.0322 (14) | 0.056 (2) |
Geometric parameters (Å, º) top
O12—C12 | 1.418 (3) | C2—H2F | 0.9600 |
O12—H12 | 0.8200 | C11—C12 | 1.520 (3) |
O13—C13 | 1.421 (3) | C11—H11 | 0.9800 |
O13—H13 | 0.8200 | C12—C13 | 1.524 (3) |
O14—C21 | 1.384 (3) | C12—H12A | 0.9800 |
O14—C14 | 1.432 (3) | C13—C14 | 1.529 (4) |
O15—C11 | 1.417 (3) | C13—H13A | 0.9800 |
O15—C15 | 1.425 (3) | C14—C15 | 1.518 (3) |
O16—C16 | 1.421 (3) | C14—H14 | 0.9800 |
O16—H16 | 0.8200 | C15—C16 | 1.512 (4) |
O17—C1 | 1.227 (4) | C15—H15 | 0.9800 |
O22—C22 | 1.415 (3) | C16—H16A | 0.9700 |
O22—H22 | 0.8200 | C16—H16B | 0.9700 |
O23—C23 | 1.425 (3) | C21—C22 | 1.525 (3) |
O23—H23 | 0.8200 | C21—H21 | 0.9800 |
O24—C24 | 1.417 (3) | C22—C23 | 1.523 (3) |
O24—H24 | 0.8200 | C22—H22A | 0.9800 |
O25—C21 | 1.422 (3) | C23—C24 | 1.517 (3) |
O25—C25 | 1.434 (3) | C23—H23A | 0.9800 |
O26—C26 | 1.423 (3) | C24—C25 | 1.528 (3) |
O26—H26 | 0.8200 | C24—H24A | 0.9800 |
N1—C1 | 1.334 (3) | C25—C26 | 1.506 (4) |
N1—C11 | 1.434 (3) | C25—H25 | 0.9800 |
N1—H1 | 0.8600 | C26—H26A | 0.9700 |
C1—C2 | 1.491 (4) | C26—H26B | 0.9700 |
C2—H2A | 0.9600 | O1—H111 | 0.82 (4) |
C2—H2B | 0.9600 | O1—H112 | 0.88 (4) |
C2—H2C | 0.9600 | O2—H211 | 0.85 (4) |
C2—H2D | 0.9600 | O2—H212 | 0.82 (4) |
C2—H2E | 0.9600 | | |
| | | |
C12—O12—H12 | 109.5 | O14—C14—C13 | 111.98 (19) |
C13—O13—H13 | 109.5 | C15—C14—C13 | 111.33 (19) |
C21—O14—C14 | 117.37 (18) | O14—C14—H14 | 109.6 |
C11—O15—C15 | 111.98 (18) | C15—C14—H14 | 109.6 |
C16—O16—H16 | 109.5 | C13—C14—H14 | 109.6 |
C22—O22—H22 | 109.5 | O15—C15—C16 | 107.04 (19) |
C23—O23—H23 | 109.5 | O15—C15—C14 | 110.06 (18) |
C24—O24—H24 | 109.5 | C16—C15—C14 | 113.54 (19) |
C21—O25—C25 | 113.61 (18) | O15—C15—H15 | 108.7 |
C26—O26—H26 | 109.5 | C16—C15—H15 | 108.7 |
C1—N1—C11 | 122.7 (2) | C14—C15—H15 | 108.7 |
C1—N1—H1 | 118.6 | O16—C16—C15 | 110.1 (2) |
C11—N1—H1 | 118.6 | O16—C16—H16A | 109.6 |
O17—C1—N1 | 122.1 (2) | C15—C16—H16A | 109.6 |
O17—C1—C2 | 121.5 (2) | O16—C16—H16B | 109.6 |
N1—C1—C2 | 116.3 (2) | C15—C16—H16B | 109.6 |
C1—C2—H2A | 109.5 | H16A—C16—H16B | 108.2 |
C1—C2—H2B | 109.5 | O14—C21—O25 | 107.14 (19) |
H2A—C2—H2B | 109.5 | O14—C21—C22 | 109.15 (19) |
C1—C2—H2C | 109.5 | O25—C21—C22 | 109.68 (19) |
H2A—C2—H2C | 109.5 | O14—C21—H21 | 110.3 |
H2B—C2—H2C | 109.5 | O25—C21—H21 | 110.3 |
C1—C2—H2D | 109.5 | C22—C21—H21 | 110.3 |
H2A—C2—H2D | 141.1 | O22—C22—C23 | 111.0 (2) |
H2B—C2—H2D | 56.3 | O22—C22—C21 | 109.16 (19) |
H2C—C2—H2D | 56.3 | C23—C22—C21 | 108.39 (19) |
C1—C2—H2E | 109.5 | O22—C22—H22A | 109.4 |
H2A—C2—H2E | 56.3 | C23—C22—H22A | 109.4 |
H2B—C2—H2E | 141.1 | C21—C22—H22A | 109.4 |
H2C—C2—H2E | 56.3 | O23—C23—C24 | 112.3 (2) |
H2D—C2—H2E | 109.5 | O23—C23—C22 | 111.9 (2) |
C1—C2—H2F | 109.5 | C24—C23—C22 | 109.98 (19) |
H2A—C2—H2F | 56.3 | O23—C23—H23A | 107.5 |
H2B—C2—H2F | 56.3 | C24—C23—H23A | 107.5 |
H2C—C2—H2F | 141.1 | C22—C23—H23A | 107.5 |
H2D—C2—H2F | 109.5 | O24—C24—C23 | 107.2 (2) |
H2E—C2—H2F | 109.5 | O24—C24—C25 | 112.3 (2) |
O15—C11—N1 | 107.11 (19) | C23—C24—C25 | 108.3 (2) |
O15—C11—C12 | 109.43 (19) | O24—C24—H24A | 109.7 |
N1—C11—C12 | 112.01 (19) | C23—C24—H24A | 109.7 |
O15—C11—H11 | 109.4 | C25—C24—H24A | 109.7 |
N1—C11—H11 | 109.4 | O25—C25—C26 | 106.4 (2) |
C12—C11—H11 | 109.4 | O25—C25—C24 | 109.92 (18) |
O12—C12—C11 | 109.4 (2) | C26—C25—C24 | 113.2 (2) |
O12—C12—C13 | 112.00 (19) | O25—C25—H25 | 109.1 |
C11—C12—C13 | 110.36 (19) | C26—C25—H25 | 109.1 |
O12—C12—H12A | 108.3 | C24—C25—H25 | 109.1 |
C11—C12—H12A | 108.3 | O26—C26—C25 | 109.9 (2) |
C13—C12—H12A | 108.3 | O26—C26—H26A | 109.7 |
O13—C13—C12 | 106.64 (19) | C25—C26—H26A | 109.7 |
O13—C13—C14 | 112.3 (2) | O26—C26—H26B | 109.7 |
C12—C13—C14 | 111.35 (19) | C25—C26—H26B | 109.7 |
O13—C13—H13A | 108.8 | H26A—C26—H26B | 108.2 |
C12—C13—H13A | 108.8 | H111—O1—H112 | 99 (5) |
C14—C13—H13A | 108.8 | H211—O2—H212 | 101 (4) |
O14—C14—C15 | 104.55 (18) | | |
| | | |
C11—N1—C1—O17 | −7.5 (4) | O15—C15—C16—O16 | −59.3 (2) |
C11—N1—C1—C2 | 173.0 (2) | C14—C15—C16—O16 | 62.3 (3) |
C15—O15—C11—N1 | 172.79 (17) | C14—O14—C21—O25 | −89.3 (2) |
C15—O15—C11—C12 | −65.6 (2) | C14—O14—C21—C22 | 151.96 (19) |
C1—N1—C11—O15 | −101.1 (3) | C25—O25—C21—O14 | −179.43 (17) |
C1—N1—C11—C12 | 139.0 (2) | C25—O25—C21—C22 | −61.1 (2) |
O15—C11—C12—O12 | −179.01 (18) | O14—C21—C22—O22 | −63.8 (2) |
N1—C11—C12—O12 | −60.4 (2) | O25—C21—C22—O22 | 179.09 (18) |
O15—C11—C12—C13 | 57.4 (2) | O14—C21—C22—C23 | 175.18 (18) |
N1—C11—C12—C13 | 175.97 (19) | O25—C21—C22—C23 | 58.1 (2) |
O12—C12—C13—O13 | 65.7 (3) | O22—C22—C23—O23 | 56.6 (3) |
C11—C12—C13—O13 | −172.24 (18) | C21—C22—C23—O23 | 176.47 (18) |
O12—C12—C13—C14 | −171.50 (19) | O22—C22—C23—C24 | −177.82 (18) |
C11—C12—C13—C14 | −49.4 (2) | C21—C22—C23—C24 | −57.9 (2) |
C21—O14—C14—C15 | −157.80 (18) | O23—C23—C24—O24 | 61.4 (2) |
C21—O14—C14—C13 | 81.5 (3) | C22—C23—C24—O24 | −63.9 (2) |
O13—C13—C14—O14 | −76.0 (2) | O23—C23—C24—C25 | −177.19 (18) |
C12—C13—C14—O14 | 164.44 (18) | C22—C23—C24—C25 | 57.5 (2) |
O13—C13—C14—C15 | 167.31 (18) | C21—O25—C25—C26 | −176.39 (19) |
C12—C13—C14—C15 | 47.8 (2) | C21—O25—C25—C24 | 60.7 (2) |
C11—O15—C15—C16 | −172.56 (18) | O24—C24—C25—O25 | 61.0 (2) |
C11—O15—C15—C14 | 63.6 (2) | C23—C24—C25—O25 | −57.2 (2) |
O14—C14—C15—O15 | −174.66 (17) | O24—C24—C25—C26 | −57.8 (2) |
C13—C14—C15—O15 | −53.6 (2) | C23—C24—C25—C26 | −176.0 (2) |
O14—C14—C15—C16 | 65.4 (2) | O25—C25—C26—O26 | 58.3 (2) |
C13—C14—C15—C16 | −173.51 (19) | C24—C25—C26—O26 | 179.1 (2) |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
O12—H12···O22i | 0.82 | 1.93 | 2.721 (3) | 162 |
O13—H13···O25 | 0.82 | 2.06 | 2.767 (3) | 144 |
O16—H16···O12ii | 0.82 | 1.93 | 2.749 (4) | 172 |
O22—H22···O13iii | 0.82 | 1.96 | 2.767 (4) | 170 |
O23—H23···O26iii | 0.82 | 1.97 | 2.753 (4) | 159 |
O24—H24···O2iv | 0.82 | 1.86 | 2.675 (3) | 171 |
O26—H26···O23i | 0.82 | 1.90 | 2.716 (5) | 173 |
N1—H1···O17v | 0.86 | 2.10 | 2.849 (4) | 146 |
O1—H111···O17v | 0.82 (4) | 2.08 (4) | 2.872 (5) | 161 (5) |
O1—H112···O16 | 0.88 (4) | 1.91 (4) | 2.782 (3) | 168 (4) |
O2—H211···O1vi | 0.85 (4) | 1.91 (4) | 2.758 (4) | 170 (5) |
O2—H212···O1 | 0.82 (4) | 2.07 (4) | 2.804 (5) | 148 (5) |
Symmetry codes: (i) x−1, y+1, z; (ii) x+1, y−1, z; (iii) x, y−1, z; (iv) x, y, z−1; (v) x+1, y, z; (vi) x−1, y, z. |
Experimental details
Crystal data |
Chemical formula | C14H25NO11·2H2O |
Mr | 419.38 |
Crystal system, space group | Triclinic, 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) |
V (Å3) | 469.8 (9) |
Z | 1 |
Radiation type | Mo Kα |
µ (mm−1) | 0.13 |
Crystal size (mm) | 0.35 × 0.35 × 0.34 |
|
Data collection |
Diffractometer | Enraf-Nonius CAD-4 diffractometer |
Absorption correction | ψ scan MolEN (Fair, 1990) |
Tmin, Tmax | 0.92, 0.96 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 1650, 1650, 1592 |
Rint | 0.000 |
(sin θ/λ)max (Å−1) | 0.594 |
|
Refinement |
R[F2 > 2σ(F2)], wR(F2), S | 0.027, 0.072, 1.04 |
No. of reflections | 1650 |
No. of parameters | 274 |
No. of restraints | 7 |
H-atom treatment | H atoms treated by a mixture of independent and constrained refinement |
Δρmax, Δρmin (e Å−3) | 0.20, −0.23 |
Selected geometric parameters (Å, º) topO14—C21 | 1.384 (3) | N1—C1 | 1.334 (3) |
O14—C14 | 1.432 (3) | N1—C11 | 1.434 (3) |
O15—C11 | 1.417 (3) | C15—C16 | 1.512 (4) |
O25—C21 | 1.422 (3) | C25—C26 | 1.506 (4) |
| | | |
C21—O14—C14 | 117.37 (18) | C1—N1—C11 | 122.7 (2) |
C11—O15—C15 | 111.98 (18) | O15—C11—N1 | 107.11 (19) |
C21—O25—C25 | 113.61 (18) | | |
| | | |
C11—N1—C1—O17 | −7.5 (4) | C21—O14—C14—C13 | 81.5 (3) |
C11—N1—C1—C2 | 173.0 (2) | O15—C15—C16—O16 | −59.3 (2) |
C1—N1—C11—O15 | −101.1 (3) | C14—O14—C21—O25 | −89.3 (2) |
C21—O14—C14—C15 | −157.80 (18) | O25—C25—C26—O26 | 58.3 (2) |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
O12—H12···O22i | 0.82 | 1.93 | 2.721 (3) | 161.7 |
O13—H13···O25 | 0.82 | 2.06 | 2.767 (3) | 143.9 |
O16—H16···O12ii | 0.82 | 1.93 | 2.749 (4) | 172.1 |
O22—H22···O13iii | 0.82 | 1.96 | 2.767 (4) | 170.1 |
O23—H23···O26iii | 0.82 | 1.97 | 2.753 (4) | 159.0 |
O24—H24···O2iv | 0.82 | 1.86 | 2.675 (3) | 171.3 |
O26—H26···O23i | 0.82 | 1.90 | 2.716 (5) | 173.2 |
N1—H1···O17v | 0.86 | 2.10 | 2.849 (4) | 145.8 |
O1—H111···O17v | 0.82 (4) | 2.08 (4) | 2.872 (5) | 161 (5) |
O1—H112···O16 | 0.88 (4) | 1.91 (4) | 2.782 (3) | 168 (4) |
O2—H211···O1vi | 0.85 (4) | 1.91 (4) | 2.758 (4) | 170 (5) |
O2—H212···O1 | 0.82 (4) | 2.07 (4) | 2.804 (5) | 148 (5) |
Symmetry codes: (i) x−1, y+1, z; (ii) x+1, y−1, z; (iii) x, y−1, z; (iv) x, y, z−1; (v) x+1, y, z; (vi) x−1, y, z. |
Comparison of selected torsional angels of lactosyl acetamide, (I),
with those of related disaccharides (°) topCompound | | ϕ | ψ | ω | ω' |
Lactosyl acetamide.H2Oa | | -89.3 | -157.8 | -59.5 | 58.1 |
Methyl β-lactoside.CH3OHb | | -88.4 | -161.3 | -54.6 | 57.3 |
Methyl β-cellobioside.CH3OHc | | -91.1 | -160.7 | -55.1 | 52.4 |
β-Lactosed | | -70.9 | -131.5 | 72.6 | 50.5 |
α-Lactose.H2Oe | | -92.6 | -143.0 | 63.2 | 59.4 |
N-Acetyl α-lactosamine.H2Of | | -88.1 | -139.5 | -56.0 | 66.8 |
α-Lactose.CaCl2.7H2Og | | -76.9 | -136.9 | 63.8 | 59.8 |
α-Lactose.CaBr2.7H2Oh | | -76.0 | -134.9 | 61.9 | 62.4 |
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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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).