Crystal structure and solid state 13C NMR analysis of nitrophenyl 2,3,4,6-tetra-O-acetyl-β-D-gluco- and D-galactopyranosides

Article abstract of DOI:10.1016/j.carres.2005.02.010

The X-ray diffraction analysis of o-nitrophenyl 2,3,4,6-tetra-O-acetyl- β-d-galactopyranoside (1), m-nitrophenyl 2,3,4,6-tetra-O-acetyl-β-d- galactopyranoside, p-nitrophenyl 2,3,4,6-tetra-O-acetyl-β-d- galactopyranoside and o-nitrophenyl 2,3,4,6-tetra-O-a

Full text of DOI:10.1016/j.carres.2005.02.010

Carbohydrate
RESEARCH
Carbohydrate Research 340 (2005) 1175–1184
13
Crystal structure and solid state C NMR analysis of nitrophenyl
2,3,4,6-tetra-O-acetyl-b-D-gluco- and D-galactopyranosides
a,
a
Tomasz Gubica, Paulina Rogowska,
a
*
AndrzejTemeriusz,
b
Katarzyna Paradowska and Michał K. Cyranski
a
´
aDepartment of Chemistry, Warsaw University, Pasteura 1, Warszawa 02-093, Poland
bDepartment of Physical Chemistry, Faculty of Pharmacy, Medical Academy, Banacha 1, 02-097 Warszawa, Poland
Received 25 November 2004; accepted 15 February 2005
Abstract—The X-ray diffraction analysis of o-nitrophenyl 2,3,4,6-tetra-O-acetyl-b-D-galactopyranoside (1), m-nitrophenyl 2,3,4,6-
tetra-O-acetyl-b-D-galactopyranoside, p-nitrophenyl 2,3,4,6-tetra-O-acetyl-b-D-galactopyranoside and o-nitrophenyl 2,3,4,6-tetra-
O-acetyl-b-D-glucopyranoside was performed. It was found that except in the case of 1, all other crystals have one molecule in
the independent part of the crystal unit cell. The results support the opinion that the nitro group does not conjugate effectively with
the phenyl ring. In the 13C CP MAS spectrum of 1 the signals are split, confirming the presence of two independent molecules. Sim-
ilarly, the 13C CP MAS NMR spectrum of p-nitrophenyl-2,3,4,6-tetra-O-acetyl-b-D-glucopyranoside indicated the presence of two
non-equivalent molecules in the crystal unit. One of these molecules has more conformational freedom enabling rotation of the phe-
nyl ring.
ꢀ 2005 Elsevier Ltd. All rights reserved.
Keywords: Crystal structure; 13C NMR analysis; Solid-state NMR; Glycosidase; Chemoenzymatic synthesis; Cholera toxin
1. Introduction
pyranoside was used in studies on the synthetic reactions
of two purified enzymes having a-D-glucosidase activi-
ties.3 Hansson et al.4 determined the activities of the
enzymes using p-nitrophenyl b-D-glucopyranoside and
p-nitrophenyl b-D-galactopyranoside as the substrates.
Nitrophenyl b-D-glycopyranosides were found to be
effective glycosyl donors for the enzymatic b-glycosida-
tion of primary alcohols.5 Also Rydon and co-work-
ers6,7 studied the mechanism of acid hydrolysis of o-,
m-, p-nitrophenyl b-D-glucopyranosides and m-, p-nitro-
phenyl-a-D-glucopyranosides. They found that ortho
substituted derivatives are hydrolyzed faster than is pre-
dicted by the substitution constant. Biosynthesis of the
a-D-glucoside of o-aminophenol, and probably p-nitro-
phenol, has been demonstrated by Dutton.8 Moreover,
3,5-substituted nitrophenyl galactosides are potential
cholera toxin antagonists.9 Since biological activity
and reaction with enzymes is closely related to molecular
structure, the compounds with different positions of ni-
tro substituents to aromatic ring were of interest. Thus
Chromogenic properties of the free aglycon of nitro-
phenyl O-glycosides are useful in enzyme studies. For
example, p-nitrophenyl a-D-galactopyranoside was used
by Wakabayashi and Nishizawa1 in enzymatic investiga-
tions on an a-D-galactosidase from bottom yeast fer-
mentary. Sheridan and Brenchley2 have isolated a
characteristic salt-tolerant family of 42 b-galactosidases
from the psychrophilic bacterium Gram-positive
Antarctic Planococcus. Enzyme activity is determined
spectrophotometrically based on the release of
p-nitrophenol from suitable p-nitrophenyl-derivative
substrates. On the other hand, p-nitrophenyl a-D-gluco-
*
Corresponding author. Fax: +48 22 822 5996; e-mail: atemer@
chem.uw.edu.pl
0008-6215/$ - see front matter ꢀ 2005 Elsevier Ltd. All rights reserved.
doi:10.1016/j.carres.2005.02.010

1176
A. Temeriusz et al. / Carbohydrate Research 340 (2005) 1175–1184
nitrophenyl galactosides and glucosides were studied by
means of X-ray diffraction and NMR spectroscopy.
Selected bond lengths, bond angles and major torsion
angles for 1–4 are given in Tables 2–4. Similar to the
o-nitrophenyl 2,3,4,6-tetra-O-acetyl-b-D-glucopyrano-
side14 the analyzed galactopyranosides (1–3) and gluco-
pyranoside (4) crystallized in the P21 space group. Due
to sharp deviations of the Flack parameter15 the abso-
lute configurations could not be determined. Instead,
they were assigned based on the knowledge of stereo-
chemistry of the synthetic precursors and the mecha-
nisms of the synthesis. Except in the case of
o-nitrophenyl 2,3,4,6-tetra-O-acetyl-b-D-galactopyrano-
side (1), all other crystals have one molecule in the inde-
pendent part of the crystal unit cell. In both molecules of
o-nitrophenyl 2,3,4,6-tetra-O-acetyl-b-D-galactopyrano-
side (1A and 1B) the nitro groups are significantly
rotated with respect to the phenyl fragment. The angle
between the best planes of the phenyl ring and the nitro
group was ꢀ61.0ꢁ and 53.9ꢁ for molecules 1A and 1B,
respectively (Table 4), and the rotation proceeds in
two directions. The extent of distortion from planarity
of the nitrobenzene fragment was comparable to that
observed in o-nitrophenyl 2,3,4,6-tetra-O-acetyl-b-D-
glucopyranoside (4) where the angle is equal to
ꢀ45.5ꢁ. Evidently, in both cases 1 and 4 the gross distor-
tions from planarity result from the steric interactions
between the nitro-fragment and sugar moiety. The ab
initio optimization (at B3LYP/6-311+G** level of the-
ory) of o-methoxynitrobenzene16 revealed that in the
optimal geometry the nitro-group is distorted by 55.5ꢁ,
and the difference in energy between this structure and
the planar one is a mere 1.2 Kcal/mol. This finding sup-
ports the earlier opinion17 that the nitro group does not
conjugate effectively with the benzene ring, and can also
be well exemplified by the geometries of p-nitrophenyl
2,3,4,6-tetra-O-acetyl-b-D-galactopyranoside (3) and m-
nitrophenyl 2,3,4,6-tetra-O-acetyl-b-D-galactopyrano-
side (2), where due to weak intermolecular interactions
2. Results and discussion
The nitrophenyl glycosides shown in Scheme 1 were pre-
pared by the reaction of the corresponding per-acetyl-a-
D-bromide with o-, m- or p-nitrophenol according to the
described procedures.10–13 Suitable crystals of o-nitro-
phenyl
2,3,4,6-tetra-O-acetyl-b-D-galactopyranoside
(1), m-nitrophenyl 2,3,4,6-tetra-O-acetyl-b-D-galactopy-
ranoside (2), p-nitrophenyl 2,3,4,6-tetra-O-acetyl-b-D-
galactopyranoside (3) and o-nitrophenyl 2,3,4,6-tetra-
O-acetyl-b-D-glucopyranoside (4) were obtained by slow
crystallization from ethanol. The crystal structures of
the four molecules (1–4) were determined in order to
ascertain their stereochemistry and solid state conforma-
tions. These data constituted a basis for solid state
NMR studies. The configuration, conformation and
atom numbering are shown in Figures 1 and 2. Crystal
data and structural refinement are specified in Table 1.
R3
CH2OAc
O
R2
AcO
R1
OAc
H
1
2
3
4
5
6
R1 = O-(2-NO2)Ph, R2 = H,
R1 = O-(3-NO2)Ph, R2 = H,
R1 = O-(4-NO2)Ph, R2 = H,
R1 = O-(2-NO2)Ph, R2 = OAc, R3 = H
R1 = O-(3-NO2)Ph, R2 = OAc, R3 = H
R1 = O-(4-NO2)Ph, R2 = OAc, R3 = H
R3 = OAc
R3 = OAc
R3 = OAc
Scheme 1.
Figure 1. ORTEP and atomic numbering of 1: o-nitrophenyl 2,3,4,6-tetra-O-acetyl-b-D-galactopyranoside.

A. Temeriusz et al. / Carbohydrate Research 340 (2005) 1175–1184
1177
Figure 2. ORTEP and atomic numbering of 2: m-nitrophenyl 2,3,4,6-tetra-O-acetyl-b-D-galactopyranoside; 3: p-nitophenyl 2,3,4,6-tetra-O-acetyl-b-
D-galactopyranoside; 4: o-nitrophenyl 2,3,4,6,-tetra-O-acetyl-b-D-glucopyranoside. The ellipsoids are drawn at the 50% probability level.
in the crystal lattice, the nitro group is rotated by ꢀ14.2ꢁ
and 6.1ꢁ, respectively.
2,3,4,6-tetra-O-acetyl-b-D-galactopyranoside (1) and
ꢀ99.6(6), 141.2(5), for o-nitrophenyl 2,3,4,6-tetra-O-
acetyl-b-D-glucopyranoside (4). Similarly, the torsion
angles C-4–C-5–C-51–O-52 and O-5–C-5–C-51–O-52
are in the range ꢀ165.2(4) and ꢀ171.9(4), 72.4(5) and
66.0(5), respectively, for two molecules of o-nitrophenyl
2,3,4,6-tetra-O-acetyl-b-D-galactopyranoside (1) and
61.0(6), ꢀ58.7(6), for o-nitrophenyl 2,3,4,6-tetra-O-acet-
yl-b-D-glucopyranoside (4). In the case of p-nitrophenyl
2,3,4,6-tetra-O-acetyl-b-D-galactopyranoside (3) and its
glucopyranoside analogue (6)14 the most significant dif-
ference concerns only the acetyl group on C-3. The tor-
sion angles C-2–C-3–O-31–C-32 and C-4–C-3–O-31–C-
32. They are equal to ꢀ155.7(2), 80.9(2) and, –112.7,
126.9, respectively, for p-nitrophenyl 2,3,4,6-tetra-O-
acetyl-b-D-galactopyranoside (3) and p-nitrophenyl
2,3,4,6-tetra-O-acetyl-b-D-glucopyranoside (6).14
The most significant difference resulting from different
packing forces between two molecules of o-nitrophenyl
2,3,4,6-tetra-O-acetyl-b-D-galactopyranoside (1) involve
the torsion angles of the C-5 and C-4 acetyl groups.
The C-3–C-4–O-41–C-42, C-5–C-4–O-41–C-42 and
C-5–C-51–O-52–C-53 torsion angles are equal to
ꢀ96.5(5), 142.3(4), 165.8(4) and ꢀ129.3(4), 111.6(5),
ꢀ139.0(5) degrees for molecules A and B, respectively.
Comparison of o-nitrophenyl 2,3,4,6-tetra-O-acetyl-b-
D-galactopyranoside (1) with o-nitrophenyl 2,3,4,6-tet-
ra-O-acetyl-b-D-glucopyranoside (4) indicates that,
apart from the obvious differences between torsion an-
gles on C-4, the changes involve the torsion angles of
the acetyl group on C-3 and C-5. The torsion angles
C-2–C-3–O-31–C-32 and C-4–C-3–O-31–C-32 are in
the range ꢀ149.9(4) and ꢀ154.3(4), 84.3(5) and
82.5(5), respectively, for two molecules of o-nitrophenyl
4
The sugar moieties adopt C1 conformations, how-
ever, due to crystal packing forces they are always

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A. Temeriusz et al. / Carbohydrate Research 340 (2005) 1175–1184
Table 1. Crystal data and structure refinement for o-nitrophenyl 2,3,4,6-tetra-O-acetyl-b-D-galactopyranoside (1) m-nitrophenyl 2,3,4,6-tetra-O-
acetyl-b-D-galactopyranoside (2) p-nitrophenyl 2,3,4,6-tetra-O-acetyl-b-D-galactopyranoside (3) and o-nitrophenyl 2,3,4,6-tetra-O-acetyl-b-D-
glucopyranoside (4)
Compound
1
2
3
4
Empirical formula
Formula weight
Temperature (K)
Space group
2C20H23NO12
938.79
110(2)
C20H23NO12
469.39
293(2)
C20H23NO12
469.39
130(2)
C20H23NO12
469.39
293(2)
P21
P21
P21
P21
Unit cell dimensions
˚
a (A)
˚
11.388(2)
8.188(2)
10.210(2)
8.435(2)
11.758(2)
5.715(2)
10.711(2)
8.276(2)
b (A)
˚
c (A)
23.867(5)
103.44(3)
13.577(3)
102.50(3)
17.379(3)
109.65(3)
12.792(3)
102.80(3)
b (ꢁ)
3
˚
Volume (A )
2164.5(7)
2
1.440
1141.6(4)
2
1.366
1099.8(4)
2
1.417
1105.8(4)
2
1.410
Z (molecules/cell)
Dcalculated (Mg/m3)
Absorption coefficient (mmꢀ1
F (000)
)
0.121
984
0.115
492
0.119
492
0.118
492
Crystal size (mm)
H range for data collection (ꢁ)
0.3 · 0.2 · 0.2
3.33–25.0
0.4 · 0.3 · 0.2
3.71–22.49
0.4 · 0.3 · 0.1
3.57–24.99
0.1 · 0.05 · 0.05
2.81–22.49
Limiting indices
ꢀ13 6 h 6 13,
ꢀ7 6 k 6 9
ꢀ10 6 h 6 10,
ꢀ8 6 k 6 9
ꢀ13 6 h 6 13,
ꢀ6 6 k 6 4
ꢀ11 6 h 6 11
ꢀ8 6 k 6 8
ꢀ28 6 l 628
16,282
ꢀ14 6 l 6 14
6863
ꢀ20 6 l 6 20
7971
ꢀ11 6 l 6 13
6272
Reflections collected
Independent reflections
Refinement method
5769 [Rint = 0.0675]
Full-matrix
Least-squares on F2
5768/1/604
2467 [Rint = 0.0259]
Full-matrix
Least-squares on F2
2467/1/303
2772 [Rint = 0.0299]
Full-matrix
Least-squares on F2
2772/1/303
2816 [Rint = .0950]
Full-matrix
Least-squares on F2
2816/1/303
Data (restraints) parameters
Goodness-of-fit on F2
1.004
1.010
1.057
0.975
Final R indices [I > 2r(I)]
R1 = 0.0596,
wR2 = 0.1220
R1 = 0.0937,
wR2 = 0.1427
0.004(1)
R1 = 0.0460,
wR2 = 0.1212
R1 = 0.0533,
wR2 = 0.1294
0.023(6)
R1 = 0.0307,
wR2 = 0.0780
R1 = 0.0333,
wR2 = 0.0801
0.016(3)
R1 = 0.0635,
wR2 = 0.1490
R1 = 0.0933,
wR2 = 0.1824
0.028(5)
R indices (all data)
Extinction coefficient
Largest difference peak and hole (e/A )
3
˚
0.598 and ꢀ0.314
0.320 and ꢀ0.211
0.161 and ꢀ0.179
0.224 and ꢀ0.222
˚
Table 2. Selected bond lengths (A) for o-nitrophenyl 2,3,4,6-tetra-O-
acetyl-b-D-galactopyranoside (1) m-nitrophenyl 2,3,4,6-tetra-O-acetyl-
b-D-galactopyranoside (2) p-nitrophenyl 2,3,4,6-tetra-O-acetyl-b-D-
galactopyranoside (3) and o-nitrophenyl 2,3,4,6-tetra-O-acetyl-b-D-
glucopyranoside (4)
slightly distorted. The most significant deviations are
found for compound (3), as quantified by the Cremer–
Pople H puckering parameters.18 The H is equal to
12.5ꢁ, while the other puckering parameters Q and u
are equal to 0.584 and 350.69. For comparison the H
is equal to 10.8ꢁ, 6.9ꢁ, 5.2ꢁ and 5.9ꢁ, respectively, for
two independent molecules of (1), as well as for (2)
and (4), while the Q and u are equal to 0.575 and
50.77 and 0.536 and 20.21, respectively, for two mole-
cules of (1), 0.576 and 2.05 for (2), 0.582 and 40.72 for
Atoms
Compound
1A
1B
2
3
4
C-1–O-5
C-1–O-1
C-1–C-2
O-1–C-6
C-2–C-3
C-3–C-4
C-4–C-5
C-5–O-5
1.395(6) 1.417(6) 1.409(4) 1.416(2) 1.402(7)
1.409(5) 1.414(6) 1.407(4) 1.402(2) 1.383(7)
1.508(7) 1.495(7) 1.519(5) 1.510(3) 1.544(9)
1.364(6) 1.378(6) 1.381(4) 1.378(2) 1.360(7)
1.506(6) 1.512(7) 1.528(5) 1.516(3) 1.524(9)
1.532(6) 1.508(7) 1.529(5) 1.535(3) 1.521(9)
1.503(7) 1.513(7) 1.513(5) 1.516(3) 1.558(9)
1.442(6) 1.431(6) 1.432(4) 1.439(2) 1.432(7)
4
(4). For an ideal chair conformation C1 the H angle
is equal to 0ꢁ. Figure 3 shows as an example the inter-
molecular interactions in the crystal lattice of P1. The
attempts to grow a suitable single crystal of 5 were
unsuccessful, and solid state structure of 6 was known
from previous XRD studies.14
The one- and two-dimensional 1H and 13C NMR
spectra for CDCl3 solutions of 1–6 were recorded and
analyzed in order to achieve a reliable assignment of
13C resonances. The spectra for solids were recorded
using the cross-polarization (CP) magic angle spinning
(MAS) technique and the 13C CP MAS NMR spectra
C-5–C-51 1.488(7) 1.501(7) 1.508(5) 1.501(3) 1.499(9)
C-7–N-7
1.471(7) 1.462(7)
1.447(10)
1.207(8)
1.202(8)
N-7–O-71 1.188(7) 1.217(6)
N-7–O-72 1.208(7) 1.229(6)
C-8–N-8
1.470(6)
1.215(5)
1.217(5)
N-8–O-81
N-8–O-82
C-9–N-9
N-9–O-91
N-9–O-92
1.470(3)
1.223(3)
1.224(3)

A. Temeriusz et al. / Carbohydrate Research 340 (2005) 1175–1184
1179
Table 3. Selected bond angles (ꢁ) for o-nitrophenyl 2,3,4,6-tetra-O-acetyl-b-D-galactopyranoside (1) m-nitrophenyl 2,3,4,6-tetra-O-acetyl-b-D-
galactopyranoside (2) p-nitrophenyl 2,3,4,6-tetra-O-acetyl-b-D-galactopyranoside (3) and o-nitrophenyl 2,3,4,6-tetra-O-acetyl-b-D-glucopyranoside
(4)
Atoms
Compound
1A
1B
2
3
4
O-1–C-1–O-5
O-5–C-1–C-2
O-1–C-1–C-2
C-6–O-1–C-1
O-31–C-3–C-4
C-2–C-3–C-4
O-41–C-4–C-5
O-41–C-4–C-3
C-5–C-4–C-3
C-42–O-41–C-4
O-5–C-5–C-4
C-51–C-5–C-4
108.8(4)
108.8(4)
109.1(4)
116.0(4)
112.0(4)
113.3(4)
108.6(4)
111.1(4)
110.1(4)
115.9(4)
111.3(4)
112.2(4)
107.6(4)
109.6(4)
106.6(4)
117.7(4)
112.8(4)
112.3(4)
109.2(4)
108.1(4)
109.5(4)
116.9(4)
111.5(4)
111.1(4)
107.1(3)
110.1(3)
107.9(3)
117.9(3)
110.8(3)
112.1(3)
109.6(3)
109.8(3)
109.0(3)
119.0(4)
110.1(3)
112.6(3)
108.2(2)
108.1(2)
108.2(2)
117.9(2)
110.9(2)
113.7(2)
111.6(2)
108.3(2)
107.8(2)
117.1(2)
109.7(2)
115.5(2)
109.1(5)
108.2(5)
106.1(5)
118.8(5)
108.0(5)
110.5(5)
107.4(5)
108.4(4)
111.0(5)
117.8(5)
108.9(5)
111.6(5)
Table 4. Selected torsion angles for o-nitrophenyl 2,3,4,6-tetra-O-acetyl-b-D-galactopyranoside (1) m-nitrophenyl 2,3,4,6-tetra-O-acetyl-b-D-
galactopyranoside (2) p-nitrophenyl 2,3,4,6-tetra-O-acetyl-b-D-galactopyranoside (3) and o-nitrophenyl 2,3,4,6-tetra-O-acetyl-b-D-glucopyranoside
(4)
Torsion angle
Compound
1A
1B
2
3
4
O-5–C-1–O-1–C-6
C-2–C-1–O-1–C-6
ꢀ82.0(5)
ꢀ89.2(5)
ꢀ77.1(4)
164.3(3)
ꢀ70.2(4)
56.7(4)
ꢀ73.6(2)
169.6(2)
ꢀ71.0(2)
55.0(2)
ꢀ86.9(6)
156.8(5)
ꢀ62.2(6)
59.9(6)
159.5(4)
ꢀ62.5(5)
62.7(5)
153.2(4)
ꢀ68.1(5)
57.9(5)
O-1–C-1–C-2–O-21
O-5–C-1–C-2–C-3
O-1–C-1–C-2–C-3
ꢀ178.8(4)
ꢀ154.7(4)
ꢀ149.9(4)
84.3(5)
174.1(4)
ꢀ152.9(4)
ꢀ154.3(4)
82.5(5)
173.3(3)
ꢀ167.7(4)
ꢀ148.0(4)
89.9(5)
171.9(2)
176.8(5)
C-1–O-1–C-6–C-7
ꢀ165.10(17)
ꢀ155.7(2)
80.9(2)
ꢀ134.8(64)
ꢀ99.6(6)
141.2(5)
128.3(6)
ꢀ111.7(6)
ꢀ58.7(6)
61.0(6)
C-2–C-3–O-31–C-32
C-4–C-3–O-31–C-32
C-5–C-4–O-41–C-42
C-3–C-4–O-41–C-42
O-5–C-5–C-51–O-52
C-4–C-5–C-51–O-52
C-5–C-51–O-52–C-53
C-4–O-41–C-42–O-42
C-4–O-41–C-42–C-43
C-6–C-7–N-7–O-71
C-6–C-7–N-7–O-72
C-11–C-10–N-10–O-101
C-11–C-10–N-10–O-102
C-8–C-7–N-7–O-71
C-8–C-7–N-7–O-72
C-8–C-9–N-9–O-91
C-8–C-9–N-9–O-92
C-9–C-10–N-10–O-101
C-9–C-10–N-10–O-102
C-10–C-9–N-9–O-91
C-10–C-9–N-9–O-92
142.3(4)
ꢀ96.5(5)
72.4(5)
111.6(5)
ꢀ129.3(4)
66.0(5)
138.5(3)
ꢀ101.8(4)
68.0(4)
99.3(2)
ꢀ142.3(2)
65.7(2)
ꢀ165.2(4)
165.8(4)
10.5(7)
ꢀ171.9(4)
ꢀ139.0(5)
ꢀ1.2(7)
ꢀ171.3(3)
ꢀ165.8(4)
ꢀ3.0(6)
ꢀ171.6(2)
154.4(2)
ꢀ5.7(3)
ꢀ156.0(6)
ꢀ5.2(10)
173.6(5)
ꢀ45.5(9)
136.4(7)
ꢀ167.2(4)
ꢀ61.0(7)
127.2(6)
ꢀ179.3(4)
53.9(7)
177.1(4)
175.5(2)
ꢀ126.8(5)
6.1(6)
ꢀ174.0(5)
118.2(6)
ꢀ53.6(7)
ꢀ125.6(5)
136.8(7)
ꢀ 41.3(10)
53.7(6)
ꢀ14.2(3)
166.7(2)
ꢀ173.6(5)
6.2(7)
165.9(2)
ꢀ13.2(3)
of 2 and 4 are illustrated in Figures 4 and 5, respectively.
Chemical shifts were assigned on the basis of liquid-state
ones. However, some solid-state resonances had signifi-
cantly different chemical shifts from their liquid-state
counterparts. These resonances were assigned, following
the same sequence as the calculated shielding constants.
The 13C NMR chemical shifts for glycosides 1–3 and
4–6, are collected in Tables 5 and 6, respectively. The
differences between solution (CDCl3) and solid state
D = dsolid ꢀ dsolution > 1 ppm are given in parentheses.
In the spectrum of o-nitrophenyl 2,3,4,6-tetra-O-acetyl-
b-D-galctopyranoside (1) the signals in 13C CP MAS
are split, confirming the presence of two independent
molecules. The most striking differences in chemical
shifts between the molecules 1A and 1B appear for C-6
(ca. 3 ppm). Remarkable differences in torsional angles:
C-5–C-51–O-52–C-53 of 165.8ꢁ and ꢀ139.0ꢁ are shown
by XRD (Table 4). The splitting of aromatic carbon

1180
A. Temeriusz et al. / Carbohydrate Research 340 (2005) 1175–1184
Figure 3. The intermolecular interactions in the crystal lattice of 1: o-nitrophenyl-2,3,4,6-tetra-O-acetyl-b-D-galactopyranoside, 2: m-nitrophenyl-
2,3,4,6-tetra-O-acetyl-b-D-galactopyranoside and 3: p-nitrophenyl-2,3,4,6-tetra-O-acetyl-b-D-galactopyranoside.
signals results from twist angles of the ring C-1–O-1–C-
6–C-7 of 154.4ꢁ in 1A and 152.8ꢁ in 1B.
shifts of the respective sugar carbons (the D values of
1–3 ppm).
Significant D values for C-1 and C-6 carbons are
observed for all compounds (Table 5), and can be
explained by the frozen reorientation around C–O
bonds in the solid phase whereas in solution these two
moieties are flexible (rotation around glycosidic bonds
and CH2O– group).
As noticed previously,14 the carbonyl bonds of the
acetyl groups on C-2, C-3 and C-4 are nearly coplanar
with respective ring C–H bonds and point in the same
direction. However, this is not the case for the peracet-
ylated glycosides studied here. Some acetyl substituents
were significantly twisted out of the plane, especially C-
4–OAc in 3 (C-5–C-4–O-41–C-42, torsional angle
99.3(2)ꢁ) and in 1 (C-3–C-4–O-41–C-42, ꢀ96.5(5)ꢁ).
The twisting was reflected in the differences in chemical
Generally, liquid-to-solid shifts reflect intramolecu-
lar as well as intermolecular interactions.19 None of
the compounds 1–6 has a hydrogen bond donor
(OH or NH) and there are no strong intermolecular
hydrogen bonds; short intermolecular contacts in the
crystals consist mainly of CHꢁ ꢁ ꢁO interactions. The
differences, D, may also result from these intermolecu-
lar effects (see the pattern of interactions illustrated in
Fig. 3). For example, in the crystal lattice the molecules
are linked by CHꢁ ꢁ ꢁO bonds with Cꢁ ꢁ ꢁO distances of
˚
˚
3.39 A in 1, and 3.54 A in 3. Inspection of data from
Table 5 indicates that these interactions do not pro-
duce significant effects on chemicals shifts (compar-
ing solution and solid-state data for the respective
carbons).

A. Temeriusz et al. / Carbohydrate Research 340 (2005) 1175–1184
1181
Figure 4. 13C CP MAS spectrum 2: m-nitrophenyl 2,3,4,6-tetra-O-acetyl-b-D-galactopyranoside.
Figure 5. 13C CP MAS spectrum 4: o-nitrophenyl 2,3,4,6-tetra-O-acetyl-b-D-glucopyranoside.
An attempt has been made to reproduce and inter-
pret NMR observations using theoretical methods.
The calculations were performed for an isolated
molecule of glycoside at its equilibrium geometry
and not for X-ray geometry (which were determined
later).
The isotropic NMR shielding constants calculated by
DFT GIAO method for 1–6 and correlation of experi-
mental (CP MAS) and theoretical (r, ppm) parameters
are collected in Tables 5 and 6. Reasonable agreement
between the experimental (CP MAS) data and theoreti-
cal shielding constants were obtained for 2–4, as indi-
cated by the correlation coefficients R2 0.985–0.99 (see
Table 5). Inspection of the final geometries of 1–6
showed that acetyl substituents are approximately pla-
nar, whereas some of them are twisted in the crystals.
These differences in geometry are the source of discrep-
ancies observed when comparing d and r values. More
striking discrepancies appear for 3 (R2 = 0.91), for which
most significant deviations from planarity are observed.
Additionally, theoretical shieldings do not reflect any
intermolecular interactions.
An interesting effect has been observed in the 13C CP
MAS NMR spectra of 6—the splitting of signals, best
observed for the resonances of C-1, C-10, C-40 and C-6
(Fig. 6). X-ray data for this compound already existed.14
The 13C CP MAS NMR spectra of 6 indicated the pres-
ence of two non-equivalent molecules in the crystal unit.
One of these molecules has more conformational free-
dom enabling rotation of the phenyl ring, as indicated
by the averaged chemical shifts of aromatic carbons
(C-20,60 127.6 ppm; C-30,50 117.8 ppm). In the second
type of molecules the ring probably has less space and
this rotation is frozen (d C-30 121.0 and C-50
111.2 ppm, C-60 126.5, C-20 127.6). A strong effect pro-
duced at carbons proximal to nitro substituent may sug-
gest its fast rotation, in addition to the dynamics of
aromatic ring.

1182
A. Temeriusz et al. / Carbohydrate Research 340 (2005) 1175–1184
Table 5. 13C NMR data (d in ppm) for nitrophenyl 2,3,4,6-tetra-O-acetyl-b-D-galactopyranosides (1–3), the isotropic NMR shielding constants
calculated by DFT and correlation of experimental (CPMAS), and theoretical (r, ppm) parameters
Atom
1A,B
dsolid
2
3
dliquid
r
dliquid
dsolid
r
dliquid
dsolid
r
C-1
C-2
C-3
C-4
C-5
C-6
100.8
67.77
70.56
66.73
71.39
61.34
100.8
96.77
99.30
68.50
70.78
67.14
71.82
61.97
96.06(ꢀ3.2)
67.30(ꢀ1.2)
69.99
83.52
98.57
68.28
70.58
66.72
71.46
61.37
99.03
69.10(1.3)
71.14
67.40
73.58
68.08
67.40
65.20
59.28
68.74
61.54
60.19
63.24
69.11
70.72(2.4)
71.84(1.3)
67.88(1.2)
74.73(3.3)
63.67(2.3)
67.57
61.91
58.52
64.77
59.52
62.72
72.21
63.53(1.6)
73.32(2.0)
65.90(4.6) A
62.83(1.5) B
149.9(6.6) A
149.4(6.0) B
142.5(1.0)
125.7
C-10
143.3
150.1
157.2
156.7
154.2
161.2
162.6(1.7)
162.9
C-20
C-30
C-40
141.4
125.1
123.8
138.5
125.9
123.6
111.4
149.2
118.3
114.2(2.8)
149.3
118.8
149.7
125.8
116.6
143.2
125.8
116.0
144.2(1.0)
103.7
131.8
139.6
124.7 A
124.0 B
115.4(ꢀ2.9)
C-50
C-60
133.7
119.7
135.0(1.3)
118.0(ꢀ1.7) A
116.6(ꢀ3.1) B
23.20, 22.90,
21.69, 20.91
130.3
123.9
129.3(ꢀ1.1)
121.7(ꢀ2.2)
127.2
117.2
116.6
125.8
119.4(2.8)
127.6(ꢀ1.8)
132.9
115.0
120.2
CH3
20.66,
20.58
20.97,
20.46,
18.92,
18.67
20.85,
20.76,
20.72,
20.69
23.57,
21.99,
20.27,
19.84
171.8,
170.4,
168.9
20.64,
20.51,
18.95,
18.79
20.71,
20.67,
20.64,
20.57
21.28,
20.03
22.87,
20.68,
18.97,
18.87
OAc
170.3
170.2
170.1
169.4
173.0, 172.6,
171.7, 170.6
171.7,
171.1,
169.5,
169.3
170.7,
170.3,
170.1,
169.5
171.7,
171.0,
170.5,
170.1
170.3,
170.1,
169.3
172.8,
172.4,
170.4
170.9,
170.3,
170.1,
169.1
Table 6. 13C NMR data (d in ppm) for nitrophenyl 2,3,4,6-tetra-O-acetyl-b-D-glucopyranosides (4–6), the isotropic NMR shielding constants
calculated by DFT and correlation of experimental (CPMAS), and theoretical (r, ppm) parameters
Atom
4
5
6A,B
dsolid
dliquid
dsolid
r
dliquid
dsolid
r
dliquid
r
C-1
100.1
102.2(2.1)
96.2
98.60
101.0(2.5)
88.42
98.04
96.43(ꢀ1.6) A
102.42(4.4) B
70.40(2.4)
71.33
88.85
C-2
C-3
C-4
C-5
C-6
68.09
70.46
68.09
72.30
61.77
67.14(ꢀ1.0)
72.42(1.0)
67.14(ꢀ1.0)
72.42
70.27
69.70
69.58
66.88
64.49
68.13
70.95
68.13
72.46
62.02
70.35(2.2)
70.35
69.64
70.18
69.68
67.03
64.11
67.99
70.91
67.99
72.42
61.81
69.44
69.97
69.53
67.18
64.18
70.35(2.2)
73.18
64.41(2.4)
70.40(2.4)
72.60
61.68
65.03(3.2) A
67.00(5.2) B
170.0 A
C-10
149.2
151.6(2.4)
151.2
157.0
157.9
154.0
161.2
162.9
165.0(3.8) B
127.6(1.8)
121.0(4.4) A
117.8(1.2) B
140.8(ꢀ2.4) A
144.7(1.5) B
111.2(ꢀ5.4) A
117.8(1.2) B
126.5 A
C-20
C-30
141.2
125.2
142.5(1.3)
124.9
142.5
126.6
111.2
149.1
107.4(ꢀ3.8)
106.9
147.5
125.8
116.6
130.8
103.6
148.8
C-40
C-50
C-60
CH3
123.9
133.8
119.8
124.9(1.0)
139.2(5.4)
123.4(3.6)
21.77
124.9
134.0
114.6
118.2
130.2
123.8
118.7
118.9
129.6
128.5
143.2
116.6
125.8
140.0
115.3
133.3
132.1(1.9)
124.6
127.6(1.8) B
22.84, 21.39,
20.69
20.69,
20.60,
20.59,
20.56
170.5,
170.2,
169.3
19.23,
19.04,
18.92,
18.90
170.6,
170.2,
170.1,
169.7
20.63,
20.59
21.15
19.19,
18.99,
18.85,
18.19
170.3,
170.0,
169.4,
169.3
20.68,
20.61,
20.59
19.19,
18.98,
18.87,
18.78
170.5,
170.0,
169.4,
169.2
OAc
172.4,
170.7
170.7,
170.1,
169.4,
169.2
170.7
170.4,
170.1,
169.4,
169.2
173.6, 172.9,
171.5, 170.4

A. Temeriusz et al. / Carbohydrate Research 340 (2005) 1175–1184
1183
Figure 6. 13C CP MAS spectrum 6: p-nitrophenyl 2,3,4,6-tetra-O-acetyl-b-D-glucopyranoside (*, spinning side band).
3. Experimental
combined filtrate and washings were concentrated, and
then the residue was crystallized from EtOH to give
the desired products.
3.1. o-Nitrophenyl 2,3,4,6-tetra-O-acetyl-b-D-galactopy-
ranoside (1)
3.5. o-Nitrophenyl 2,3,4,6-tetra-O-acetyl-b-D-glucopyr-
anoside (4)
This compound was prepared according to the proce-
dures described by Seidman and Link.10 White crystals,
20
D
yield, 48%; mp 175–176 ꢁC, lit.10 172–172.5 ꢁC; ½aꢂ
This compound was prepared according to the general
procedure. White crystals, yield, 46%; mp 161–162 ꢁC,
18
+55.4ꢁ (CHCl3); ½aꢂ +69.9ꢁ (CHCl3).
D
20
D
22
D
½aꢂ +40.6 (CHCl3) lit.13 157–158 ꢁC; ½aꢂ +37 (CHCl3).
3.2. m-Nitrophenyl 2,3,4,6-tetra-O-acetyl-b-D-galactopy-
ranoside (2)
3.6. m-Nitrophenyl 2,3,4,6-tetra-O-acetyl-b-D-glucopyr-
anoside (5)
This compound was prepared according to the proce-
dures described by Sidhu and co-workers.11 White crys-
This compound was prepared according to the general
procedure. White crystals, yield, 38%; mp 141–142 ꢁC,
20
tals, yield, 52%; mp 109–111 ꢁC, ½aꢂ ꢀ8.1 (CHCl3) lit.11
D
22
105–106 ꢁC; ½aꢂ ꢀ8 (CHCl3).
20
D
22
D
½aꢂ ꢀ35.7 (CHCl3) lit.13 138–139 ꢁC; ½aꢂ ꢀ40 (CHCl3).
D
3.3. p-Nitrophenyl 2,3,4,6-tetra-O-acetyl-b-D-galactopy-
ranoside (3)
3.7. p-Nitrophenyl 2,3,4,6-tetra-O-acetyl-b-D-glucopyr-
anoside (6)
This compound was prepared according to the proce-
dures described by Matta and Barlow.12 White crystals,
This compound was prepared according to the general
procedure. White crystals, yield, 30%; mp 177–
20
yield, 49%; mp 146–147 ꢁC, ½aꢂ ꢀ9.7 (CHCl3), lit.12 mp
20
D
22
D
178.5 ꢁC, ½aꢂ ꢀ38.6 (CHCl3) lit.13 175–177 ꢁC; ½aꢂ
D
23
140–142 ꢁC; ½aꢂ ꢀ11.3 (CHCl3).
ꢀ27 (CHCl3).
D
3.4. General synthesis of nitrophenyl 2,3,4,6-tetra-O-
acetyl-b-D-glucopyranoside
3.8. Physical measurements
X-ray measurements were performed on a Kuma
KM4CCD j-axis diffractometer with graphite-mono-
chromated MoKa radiation (0.71073 A). The crystals
of 1 and 3 were measured at 110 and 130 K, respectively,
whereas 2 and 4 were measured at 293 K because their
crystals were unstable when cooling, (the reason for sig-
nificantly bigger thermal ellipsoids in their case). The
crystals were positioned at 62.3 mm from the KM4CCD
camera, 500 frames were measured at 1.2ꢁ intervals with
A mixture of tetra-O-acetyl-a-D-glucopyranosyl bro-
mide (2 mmol), appropriate nitrophenol (4 mmol), silver
carbonate (3 mmol) and anhydrous calcium sulfate
(Dreirite) in acetonitrile (40 mL) was refluxed for 1 h.
After filtration, the mixture was concentrated. The resi-
due was crystallized from ethanol. A solution of the ob-
tained crystals in chloroform was filtered through a
layer of silica gel, and washed with chloroform. The
˚

1184
A. Temeriusz et al. / Carbohydrate Research 340 (2005) 1175–1184
a counting time of 25 s, 600 frames were measured at
1.0ꢁ intervals with a counting time of 20 s, 600 frames
were measured at 1.0ꢁ intervals with a counting time
of 10 s, and 748 frames were measured at 0.8 intervals
with a counting time of 50 s, respectively. The data were
corrected for Lorentz and polarization effects. The
numerical absorption correction was not applied. Data
reduction and analysis were carried out with the Kuma
Diffraction (Wrocław, Poland) programs. The structures
were solved by direct methods20 and refined using
SHELXL.21 The refinement was based on F2 for all reflec-
tions except for those with very negative F2. The
weighted R factor, wR and all goodness-of-fit S values
are based on F2. The non-hydrogen atoms were refined
anisotropically, whereas the H-atoms were placed in
the calculated positions. Scattering factors were taken
from Tables 6.1.1.4 and 4.2.4.2 in Ref. 22.
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4. Supplementary data
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Financial support from the Warsaw University (BST-
831/14/2003) is gratefully acknowledged. The X-ray
measurements were undertaken in the Crystallographic
Unit of the Physical Chemistry Laboratory at the Chem-
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