Molecular and crystal structures of N-aryl-β-D-glycopyranosylamines from mannose and galactose

Article abstract of DOI:10.1016/S0008-6215(01)00117-3

The molecular and crystal structures of 12 N-aryl-β-D-glycopyranosylamines have been determined by X-ray crystallography. Six of these are mannose derivatives, the N-p-bromophenyl (1), N-p-tolyl (2), N-m-chlorophenyl (3), N-p-methoxyphenyl (4), N-o-chlorophenyl (5), and N-o-tolyl (6) derivatives that are formed by reaction with the corresponding substituted anilines. The remaining six are galactose derivatives, the N-phenyl (7), N-p-chlorophenyl (8), N-p-bromophenyl (9), N-p-iodophenyl (10), N-p-nitrophenyl (11) and N-p-tolyl (12), derivatives prepared similarly. Compounds 1-3 assume the same packing arrangement. Compounds 4, 5, and 6 assume unique packing arrangements, although that assumed by 4 is closely related to that assumed by 1-3. Compounds 7-11 assume the same packing arrangement; that assumed by 12 is closely related to that assumed by 7-11. That the same packing arrangements can be maintained in spite of substantial changes in the electronic and steric nature of the substituent on the aryl ring reflects the strength of the hydrogen bond network connecting the monosaccharide portions of the molecules in the solid state. A hydrogen bonding motif found in all six mannose structures is a mutual interaction between translationally related molecules involving O-3-H···O-5 and O-6-H···O-4 hydrogen bonds. The recurrence of this motif throughout this group of mannosylamines suggests that it is an especially favorable interaction that might be expected to occur also in related macromolecular systems.

Full text of DOI:10.1016/S0008-6215(01)00117-3

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Carbohydrate Research 332 (2001) 415–427
Molecular and crystal structures of
N-aryl-b-
D
-glycopyranosylamines from mannose and
galactose
Charles R. Ojala,a Joanne M. Ostman,a Summer E. Hanson,b William H. Ojalab,*
aDepartment of Chemistry, Normandale Community College, Bloomington, MN 55431, USA
bDepartment of Chemistry, Uni6ersity of St. Thomas, Mail cOSS 402, 2115 Summit A6enue, St. Paul,
MN 55105, USA
Received 6 July 2000; accepted 15 April 2001
Abstract
The molecular and crystal structures of 12 N-aryl-b-
D
-glycopyranosylamines have been determined by X-ray
crystallography. Six of these are mannose derivatives, the N-p-bromophenyl (1), N-p-tolyl (2), N-m-chlorophenyl (3),
N-p-methoxyphenyl (4), N-o-chlorophenyl (5), and N-o-tolyl (6) derivatives that are formed by reaction with the
corresponding substituted anilines. The remaining six are galactose derivatives, the N-phenyl (7), N-p-chlorophenyl
(8), N-p-bromophenyl (9), N-p-iodophenyl (10), N-p-nitrophenyl (11) and N-p-tolyl (12), derivatives prepared
similarly. Compounds 1–3 assume the same packing arrangement. Compounds 4, 5, and 6 assume unique packing
arrangements, although that assumed by 4 is closely related to that assumed by 1–3. Compounds 7–11 assume the
same packing arrangement; that assumed by 12 is closely related to that assumed by 7–11. That the same packing
arrangements can be maintained in spite of substantial changes in the electronic and steric nature of the substituent
on the aryl ring reflects the strength of the hydrogen bond network connecting the monosaccharide portions of the
molecules in the solid state. A hydrogen bonding motif found in all six mannose structures is a mutual interaction
between translationally related molecules involving O-3ꢀH···O-5 and O-6ꢀH···O-4 hydrogen bonds. The recurrence of
this motif throughout this group of mannosylamines suggests that it is an especially favorable interaction that might
be expected to occur also in related macromolecular systems. © 2001 Elsevier Science Ltd. All rights reserved.
Keywords: X-ray crystal structure; Glycosylamines; Hydrogen bonding; Monosaccharides, structure; Mannose derivatives;
Galactose derivatives
1. Introduction
base and given monosaccharide could lend
insight into the nature of similar linkages im-
portant in macromolecular systems, such as
the N-glycosylic linkage connecting carbohy-
Reaction of a monosaccharide with a ni-
trogenous base yields a derivative that could
exist as an open-chain Schiff base or as a
cyclic glycosylamine (Scheme 1). An under-
standing of the conditions that determine
which linkage actually forms between a given
drates
to
asparagine
residues
in
glycoproteins1,2 and the semicarbazide linkage
connecting biotinylated labeling agents to
oligosaccharides.3–5 Previous studies in solu-
tion and in the solid state have shown that
whether the monosaccharide derivative is a
cyclic or acyclic compound depends on such
* Corresponding author. Fax: +1-651-9625209.
E-mail address: whojala@stthomas.edu (W.H. Ojala).
0008-6215/01/$ - see front matter © 2001 Elsevier Science Ltd. All rights reserved.
PII: S0008-6215(01)00117-3

416
C.R. Ojala et al. / Carbohydrate Research 332 (2001) 415–427
acyclic structures, opinion on this point was
divided,12–15 but spectroscopic and X-ray crys-
tallographic evidence supporting the cyclic
form has accumulated since.16–19 Recently, by
means of X-ray crystallography, we deter-
mined the molecular and crystal structures of
two cyclic derivatives of this type, N-phenyl-
factors as the identity of the monosaccharide,
the strength of the base, and the proton-ac-
cepting ability of the solvent.6 Different
monosaccharides yield different products, re-
action of
ing a crystalline N-glucopyranosylhydroxyl-
amine but reaction of -arabinose with hy-
D
-glucose with hydroxylamine yield-
D
droxylamine yielding crystalline syn and anti
forms of the open-chain oxime.7,8 Moreover,
its behavior with hydroxylamine notwith-
mannopyranosylamine
and
N-(p-chloro-
phenyl)mannopyranosylamine, as well as the
structures of the open-chain oxime and the
standing,
mophenylhydrazine to form a crystalline
arabinopyranosylamine9 as does
-arabinose
D
-arabinose reacts with p-bro-
cyclic semicarbazide derivative of
D
-mann-
ose.20 We found the preference of the mann-
ose ‘anilide’ for the cyclic form to be particu-
larly interesting, given that mannose phenyl-
hydrazone, which differs from the ‘anilide’ in
composition by only a single ꢀNH-group, is
an open-chain compound in the solid state.21
These results raised the question of whether
the reaction of a monosaccharide with a pri-
mary aromatic amine would always yield a
crystalline glycosylamine regardless of the na-
ture (such as electron-donating versus elec-
tron-withdrawing) of any substituents present
on the aromatic ring. Beyond the question of
the cyclic or acyclic nature of the derivative,
we also wished to address the larger question
of whether a study of these small-molecule
systems would reveal characteristic structural
features (such as preferred hydrogen-bonding
patterns) that could also apply to macro-
molecular systems. We subsequently prepared
a series of these derivatives differing in their
ring substitution and determined their struc-
tures by means of X-ray crystallography. In
each case the derivative was found to be a
glycopyranosylamine. In this report we de-
scribe the molecular and crystal structures of
six mannopyranosylamines, the N-p-bro-
L
upon reaction with p-toluenesulfonylhy-
drazide.10 In each case it is likely that an
equilibrium between the various forms is in
effect in solution, but which form ultimately
will crystallize from solution is not readily
predicted, the form predominant in the solid
state not necessarily being the form predomi-
nant in solution.6,11
Both Schiff bases and glycosylamines might
result also from the reaction of monosacchar-
ides with primary aromatic amines. In the
early literature concerning the question of
whether sugar ‘anilides’ assume cyclic or
mophenyl
(1),
N-p-tolyl
(2),
N-m-
chlorophenyl (3), N-p-methoxyphenyl (4),
N-o-chlorophenyl (5), and N-o-tolyl (6)
derivatives formed upon reaction of
D
-mann-
ose with the corresponding substituted anili-
nes. We also report here the molecular and
crystal structures of six galactopyranosyl-
amines, the N-phenyl (7), N-p-chlorophenyl
(8), N-p-bromophenyl (9), N-p-iodophenyl
(10), N-p-nitrophenyl (11), and N-p-tolyl (12)
Scheme 1. Schiff base (left) and b-
forms of a derivative formed by reaction between
(top) or -galactose (bottom) and a nitrogenous base R-NH2.
Compounds 1–12 occur as b-D-glycosylamines in the solid
state.
D
-glycosylamine (right)
D
-mannose
D
derivatives formed upon reaction of
tose with the corresponding anilines.
D
-galac-

C.R. Ojala et al. / Carbohydrate Research 332 (2001) 415–427
417
ranosylamines or b-
D
-galactopyranosylamines
4
having the C1 conformation. Cremer–Pople
puckering parameters23–25 (calculated using
the program PLATON-9426) and asymmetry
parameters DCs27 (also from PLATON-94) for
compounds 1–12 are given in Table 1. In
most of these structures the effects on bond
lengths of changing the nature or position of
the aryl substituent are minimal, bonds such
as O-5ꢀC-1, N-1ꢀC-1, and N-1ꢀC-7 showing
no significant differences in length from struc-
ture to structure. An exception is the nitro-
substituted compound 11, which has an
22
Fig. 1. ORTEPII drawing of 11, showing atom numbering.
The ellipsoids are drawn at the 50% probability level.
2. Results and discussion
Molecular geometry.—An ORTEPII22 view of
11 showing the atom numbering scheme and
molecular conformation is given in Fig. 1.
(Compound 11 was chosen for this view so
that the orientation of the nitro group with
respect to the phenyl ring could be shown.)
Similar atom numbering schemes apply to 1–
10 and 12. All of these compounds are cyclic
,
N-1ꢀC-7 bond length of 1.381(3) A as op-
,
posed to lengths of 1.401–1.410 A for this
bond found in the other galactopyranosy-
lamines examined here. Lengths for this bond
,
,
of 1.377(5) A and 1.383(3) A have been re-
ported for N-p-nitrophenyl-N-(2,3,4-tri-O-
acetyl-b-
D
-lyxopyranosyl)amine and N-p-
nitrophenyl - N - (2,3,4 - tri - O - acetyl - a -
L
-
in the solid state, occurring as b- -mannopy-
D
Table 1
Cremer–Pople puckering parameters and asymmetry parameters
1
2
5
8
3
,
Q (A)
[ (°)
0.567(5)
5.7(4)
0.563(2)
4.9(2)
1.3(32)
7.36(17)
7.39(19)
0.3(2)
0.559(3)
2.5(3)
b (°)
348.8(49)
9.5(4)
358.1(68)
6.2(2)
DCS(C-1, C-4) (°)
DCS(C-2, C-5) (°)
DCS(C-3, O-5) (°)
7.5(4)
2.1(4)
5.7(2)
0.8(2)
4 a
6
,
Q (A)
0.565(12); 0.574(12)
3.8(11); 175.9(11)
360.0(180); 170.4(170)
7.2(9); 6.9(10)
7.3(10); 6.8(10)
0.8(10); 0.9(10)
0.602(4)
4.4(4)
25.3(53)
6.2(3)
7.8(3)
1.7(3)
0.594(2)
2.8(2)
[ (°)
b (°)
22.6(37)
5.45(16)
6.55(16)
1.15(16)
DCS(C-1, C-4) (°)
DCS(C-2, C-5) (°)
DCS(C-3, O-5) (°)
7
9
,
Q (A)
[ (°)
0.591(2)
3.3(3)
300.1(42)
6.48(19)
3.57(19)
3.30(17)
0.586(2)
3.6(3)
273.4(38)
5.53(16)
2.07(16)
4.09(16)
0.570(4)
2.3(4)
272.2(65)
5.4(3)
1.9(3)
4.5(3)
b (°)
DCS(C-1, C-4) (°)
DCS(C-2, C-5) (°)
DCS(C-3, O-5) (°)
10
11
12 a
,
Q (A)
[ (°)
0.648(49)
5.6(45)
295.3(459)
9(4)
0.589(2)
2.8(3)
0.584(3); 0.592(3)
4.1(3); 3.6(3)
248.2(53); 253.1(36)
3.8(2); 4.2(2)
1.7(2); 1.6(2)
3.6(2); 4.8(2)
b (°)
263.4(61)
4.90(16)
2.57(16)
2.66(16)
DCS(C-1, C-4) (°)
DCS(C-2, C-5) (°)
DCS(C-3, O-5) (°)
4(4)
8(4)
a First entry refers to O-5 ring; second entry refers to O-25 ring.

418
C.R. Ojala et al. / Carbohydrate Research 332 (2001) 415–427
Table 2
Selected torsional angles (°)
1
2
3
O-5ꢀC-1ꢀN-1ꢀC-7
O-5ꢀC-5ꢀC-6ꢀO-6
O-6ꢀC-6ꢀC-5ꢀC-4
C-1ꢀN-1ꢀC-7ꢀC-8
C-1ꢀN-1ꢀC-7ꢀC-12
C-2ꢀC-1ꢀN-1ꢀC-7
−76.1(5)
74.9(5)
−164.5(4)
−175.7(4)
1.7(7)
−69.9(2)
74.0(2)
−164.7(2)
179.2(2)
−2.4(3)
169.2(2)
−74.6(3)
73.6(3)
−164.9(2)
172.1(3)
−9.2(5)
165.2(3)
164.0(4)
a
4
5
6
O-5ꢀC-1ꢀN-1ꢀC-7
O-5ꢀC-5ꢀC-6ꢀO-6
O-6ꢀC-6ꢀC-5ꢀC-4
C-1ꢀN-1ꢀC-7ꢀC-8
C-1ꢀN-1ꢀC-7ꢀC-12
C-2ꢀC-1ꢀN-1ꢀC-7
C-9ꢀC-10ꢀO-7ꢀC-13
C-11ꢀC-10ꢀO-7ꢀC-13
−69.9(3); −70.0(3)
73.1(3); 73.7(3)
−165.1(2); −164.6(2)
−177.6(3); 176.7(2)
2.2(4); −6.7(4)
169.1(2); 169.0(2)
−167.4(4); −7.1(5)
8.4(5); 175.0(3)
−67.4(3)
47.6(3)
166.7(2)
−178.1(3)
2.2(5)
−67.0(3)
−64.9(2)
57.4(2)
179.6(2)
−0.9(3)
171.1(2)
173.0(3)
7
8
9
O-5ꢀC-1ꢀN-1ꢀC-7
O-5ꢀC-5ꢀC-6ꢀO-6
O-6ꢀC-6ꢀC-5ꢀC-4
C-1ꢀN-1ꢀC-7ꢀC-8
C-1ꢀN-1ꢀC-7ꢀC-12
C-2ꢀC-1ꢀN-1ꢀC-7
−70.7(3)
175.2(2)
−62.3(3)
167.6(2)
−16.1(4)
167.6(2)
−73.9(2)
−179.8(2)
−57.4(3)
170.1(2)
−13.5(4)
165.1(2)
−74.8(4)
179.8(2)
−55.8(4)
171.0(3)
−11.4(6)
164.0(3)
10
11
12a
O-5ꢀC-1ꢀN-1ꢀC-7
O-5ꢀC-5ꢀC-6ꢀO-6
O-6ꢀC-6ꢀC-5ꢀC-4
C-1ꢀN-1ꢀC-7ꢀC-8
C-1ꢀN-1ꢀC-7ꢀC-12
C-2ꢀC-1ꢀN-1ꢀC-7
C-9ꢀC-10ꢀN-2ꢀO-7
C-9ꢀC-10ꢀN-2ꢀO-8
C-11ꢀC-10ꢀN-2ꢀO-7
C-11ꢀC-10ꢀN-2ꢀO-8
−76.9(10)
179.7(6)
−58(1)
172.9(9)
−10(1)
163.7(7)
−76.2(3)
178.4(2)
−60.1(3)
167.9(2)
−13.6(4)
163.2(2)
−173.1(3)
6.7(4)
−73.5(3); −75.6(3)
179.2(2); −179.9(2)
−58.1(3); −58.0(3)
158.1(2); −176.0(2)
−25.2(4); 2.5(4)
165.8(2); 163.0(2)
6.0(4)
−174.2(3)
a Two independent molecules in the asymmetric unit. For the names of the atoms defining the second torsional angle, add 20
to the atom number of each atom defining the first torsional angle.
for pyranosides.28 The orientation of the sub-
arabinopyranosyl)amine,
respectively,
in
stituent in the structures of the meta-substi-
tuted compound 3 and the ortho-substituted
compounds 5 and 6 is outward and away from
the monosaccharide. Of all the mannopyran-
osylamines we have examined thus far, only
one, compound 6, does not have the gt con-
formation at the C-6ꢀO-6 side chain. In 6 this
conformation is gg. In all of the galactopyran-
osylamine structures included here, the con-
formation of the C-6ꢀO-6 side chain is tg.29 In
4 the two molecules in the asymmetric unit are
distinguished from each other by the different
orientations of their methoxy substituents; in
12 the two are distinguished by a difference in
which delocalization of the electron pair from
the glycosidic nitrogen into the nitro-substi-
tuted aryl ring has been suggested.17
Selected torsional angles for 1–12 are listed
in Table 2. The torsional angles defining the
aglycone conformation do not vary greatly
from structure to structure in spite of the
differences in aryl ring substitution. In all
cases, the gauche O-5ꢀC-1ꢀN-1ꢀC-7 torsional
angle places the N-1ꢀC-7 bond in a staggered
orientation with respect to the C-1ꢀH-1 and
C-1ꢀO-5 bonds and anti with respect to the
C-1ꢀC-2 bond. This corresponds to the E1
conformation reported to be especially stable

C.R. Ojala et al. / Carbohydrate Research 332 (2001) 415–427
419
Table 3
Table 3 (Continued)
DꢀH···A
Hydrogen-bond parametersa
,
D···A (A)
DꢀH···A (°)
,
DꢀH···A
D···A (A)
DꢀH···A (°)
O-6ꢀH-60···O-3xiv
O-6ꢀH-60···O-4xiv
N-1ꢀH-70···O-2ii
2.784(4)
3.247(4)
3.100(4)
161
117
156
1
2
3
4
O-2ꢀH-20···O-4i
O-3ꢀH-30···O-5ii
O-4ꢀH-40···O-3iii
O-6ꢀH-60···O-4iv
N-1ꢀH-70···O-6i
O-2ꢀH-20···O-4i
O-3ꢀH-30···O-5ii
O-4ꢀH-40···O-3iii
O-6ꢀH-60···O-4iv
N-1ꢀH-70···O-6i
O-2ꢀH-20···O-4i
O-3ꢀH-30···O-5ii
O-4ꢀH-40···O-3iii
O-6ꢀH-60···O-4iv
N-1ꢀH-70···O-6i
3.037(6)
2.815(4)
2.735(4)
2.792(4)
3.114(6)
149
156
141
141
150
10
11
12
O-2ꢀH-20···O-4iii
O-2ꢀH-20···O-6ix
O-3ꢀH-30···O-4iii
O-4ꢀH-40···O-3ii
O-6ꢀH-60···O-3xiv
O-6ꢀH-60···O-4xiv
N-1ꢀH-70···O-2ii
3.080(9)
2.741(9)
2.946(8)
2.830(9)
2.783(9)
3.273(9)
3.11(1)
90(10)
161(15)
138
2.943(2)
2.798(2)
2.704(2)
2.772(2)
3.113(3)
155(3)
171(2)
175(3)
171(2)
156(2)
121
144(13)
117(11)
168
O-2ꢀH-20···O-6ix
O-3ꢀH-30···O-4iv
O-4ꢀH-40···O-2xiv
O-4ꢀH-40···O-3xiv
O-6ꢀH-60···O-3xiv
O-6ꢀH-60···O-4xiv
N-1ꢀH-70···O-2ii
2.707(3)
2.810(3)
3.226(2)
2.930(2)
2.802(2)
3.241(3)
3.098(3)
152(2)
164(3)
129(3)
160(3)
147(3)
139(3)
160(3)
2.995(3)
2.793(3)
2.727(3)
2.758(3)
3.133(4)
150(4)
178(4)
172(4)
172(4)
148(3)
O-2ꢀH-20···O-4i
2.927(3)
2.809(2)
2.706(3)
2.792(3)
3.134(3)
2.927(3)
2.805(2)
2.709(3)
2.763(3)
3.098(3)
151(3)
170(3)
165(3)
161(3)
162(3)
149(3)
172(3)
177(3)
176(3)
151(2)
O-3ꢀH-30···O-25ii
O-4ꢀH-40···O-23v
O-6ꢀH-60···O-24vi
N-1ꢀH-70···O-6i
O-2ꢀH-20···O-6ix
2.733(2)
2.790(3)
3.079(2)
2.966(2)
2.778(3)
2.723(3)
2.806(2)
3.042(3)
2.948(2)
2.763(3)
3.273(3)
3.132(3)
3.104(3)
152(3)
164(3)
113(2)
170(3)
158(3)
156(3)
157(3)
135(3)
151(3)
161(3)
122(2)
174(3)
164(3)
O-3ꢀH-30···O-24vi
O-4ꢀH-40···O-22xv
O-4ꢀH-40···O-23xv
O-6ꢀH-60···O-23xv
O-22ꢀH-220···O-26ix
O-23ꢀH-230···O-4iv
O-24ꢀH-240···O-2xv
O-24ꢀH-240···O-3xv
O-26ꢀH-260···O-3xv
O-26ꢀH-260···O-4xv
N-1ꢀH-70···O-22ii
N-21ꢀH-270···O-2vi
O-22ꢀH-220···O-24i
O-23ꢀH-230···O-5vi
O-24ꢀH-240···O-3v
O26ꢀH-260···O-4iv
N-21ꢀH-270···O-26i
5
O-2ꢀH-20···O-6vii
O-3ꢀH-30···O-2i
O-3ꢀH-30···O-5i
O-4ꢀH-40···O-3viii
O-6ꢀH-60···O-4ix
2.673(3)
3.136(3)
3.127(3)
2.781(3)
2.718(3)
146
144(3)
145(3)
158
163(4)
6
7
O-2ꢀH-20···O-3x
O-3ꢀH-30···O-5xi
O-4ꢀH-40···O-6xii
O-6ꢀH-60···O-4xiii
O-2ꢀH-20···O-6ix
O-3ꢀH-30···O-4iv
O-4ꢀH-40···O-2xiv
O-4ꢀH-40···O-3xiv
O-6ꢀH-60···O-3xiv
O-6ꢀH-60···O-4xiv
N-1ꢀH-70···O-2ii
O-2ꢀH-20···O-6ix
O-3ꢀH-30···O-4iv
O-4ꢀH-40···O-2xiv
O-4ꢀH-40···O-3xiv
O-6ꢀH-60···O-3xiv
O-6ꢀH-60···O-4xiv
N-1ꢀH-70···O-2ii
O-2ꢀH-20···O-6ix
O-3ꢀH-30···O-4iv
O-4ꢀH-40···O-2xiv
O-4ꢀH-40···O-3xiv
2.727(2)
2.850(2)
2.666(2)
2.653(2)
169(3)
169(2)
165(3)
156(3)
a Symmetry codes: (i) x, 1+y, z; (ii) −1+x, y, z; (iii) 1−x,
−1/2+y, 1−z; (iv) 1+x, y, z; (v) −x, −1/2+y, −z (vi) xyz;
(vii) −1/2+x, 1/2+y, z; (viii) −x, y, −z; (ix) x, −1+y, z;
(x) 1/2−x, 1−y, −1/2+z; (xi) x, y, 1+z; (xii) −1/2−x,
1−y, 1/2+z; (xiii) x, y, −1+z; (xiv) 1−x, 1/2+y, 1−z; (xv)
−x, 1/2+y, −1−z.
2.793(3)
2.882(3)
3.201(3)
2.964(3)
2.819(3)
3.212(3)
3.198(3)
151(3)
161(3)
127(3)
163(3)
149(3)
136(3)
171(3)
the twist of the aryl ring with respect to the
monosaccharide.
Packing arrangements and intermolecular in-
teractions.—An unanticipated result of these
structure determinations was finding that even
a substantial change in the ring substituent
not only had no effect on the structure of the
derivative (at least in determining whether it
was cyclic or acyclic) but also in many cases
had no effect on its packing arrangement.
Among these mannopyranosylamines, com-
pounds 1–3 are isostructural with each other
and with the previously reported N-(p-
chlorophenyl)mannopyranosylamine. Among
8
9
2.722(2)
2.808(2)
3.106(2)
2.936(2)
2.796(2)
3.258(2)
3.107(3)
161(3)
155(3)
130(3)
158(3)
161(3)
122(2)
168(3)
2.715(4)
2.806(3)
3.090(3)
2.950(3)
158
137
104
159

420
C.R. Ojala et al. / Carbohydrate Research 332 (2001) 415–427
by two hydrogen-bonding interactions, O-
3ꢀH···O-5 (−1+x, y, z) and O6ꢀH···O-4
(1+x, y, z), which define a ten-membered
hydrogen-bonded ring connecting pairs of
translationally related monosaccharides. The
chains are connected side-by-side along the b
axis, forming layers, by a pair of hydrogen
bonds, O-2ꢀH···O-4 (x, 1+y, z) and N-
1ꢀH···O-6 (x, 1+y, z), again linking transla-
tionally related molecules. Layers are stacked
on top of each other along the c axis such that
the monosaccharide moieties of a given layer
interact with the monosaccharide moieties of a
neighboring layer (an interaction involving a
hydrogen bond, O-4ꢀH···O-3 (1−x, −1/2+
y, 1−z)) while the aryl rings of the given
layer interact with the aryl rings of its other
neighboring layer. This arrangement produces
an alternating pattern of layers in the c direc-
tion that generates the screw axial symmetry
of the packing and defines an alternating pat-
tern of hydrophilic (monosaccharides) and hy-
drophobic (aryl groups) regions in the crystal.
these six galactopyranosylamines, only two
packing arrangements are represented, and
only compound 12 assumes a unique one.
Moreover, the packing arrangement assumed
by 12 is closely related to that assumed by
7–11. This isostructuralism occurs in spite of
differences in ring substitution that include
not only simple halogen-for-halogen ex-
changes but also replacement of the halogens
with a hydrogen atom, the methyl group, and
the nitro group, substituents that are signifi-
cantly different from the halogens sterically
and electronically. In 3, even the replacement
of a para substituent with a meta substituent
leaves the packing arrangement undisturbed.
On the other hand, we have also found that
certain of these derivatives that might be ex-
pected to assume similar packing arrange-
ments because of the similarity of their ring
substituents actually do not. The ortho-substi-
tuted mannopyranosylamines 5 and 6, related
by the exchange of a chlorine atom for a
methyl group, assume unique packing ar-
rangements even though the para-substituted
analogues are isostructural with each other.
Details of the hydrogen bonding in 1–12
are given in Table 3. In the mannopyran-
osylamine series, each of the potential hydro-
gen bond donor atoms does in fact serve as a
donor in at least one of these structures, al-
though approaches involving the NꢀH bond
are not very close. With the exception of a
weak interaction in 5, O-2 does not serve as
an acceptor atom in any of the structures 1–6,
nor does N-1, but the remaining potential
acceptors O-3, O-4, O-5, and O-6 all do. In
the galactopyranosylamine series, only O-5
does not serve as an acceptor. All of the
potential donors participate in hydrogen
bonding, but again the N–H interactions are
not especially close. The nitro group of 11
does not participate in hydrogen bonding, un-
like the nitro group of a similar galactopyran-
In
N-phenylmannopyranosylamine20
the
stacking of layers is different, but the inter-
molecular hydrogen bonding pattern is the
same as that found in 1–3 and in the N-(p-
chlorophenyl)mannopyranosylamine
ture.
struc-
In the early stages of the structure determi-
nation, the unit cell of 4 was found to be
similar to those of 1–3 with the exception that
oside
reported
recently,
2-nitrophenyl
1-thio-b-
D
-galactopyranoside.30
The packing arrangement assumed by 1 is
shown in Fig. 2; compounds 2, 3, and the
N-(p-chlorophenyl)mannopyranosylamine de-
scribed previously20 pack in this same manner.
Molecules in this packing arrangement are
linked into chains extending along the a axis
Fig. 2. Molecular packing in 1.

C.R. Ojala et al. / Carbohydrate Research 332 (2001) 415–427
421
independent molecules identical and transla-
tionally related, the repeat distance along a
would become half what was found, and the
unit cell and the overall packing arrangement
would become identical to those of 1–3. In
fact, the hydrogen bonding scheme found in 4
is essentially the same as that found in these
other structures. The only significant differ-
ence is that certain hydrogen bonds linking
molecules that are translationally related in
1–3 link molecules that are crystallographi-
cally independent in 4.
The packing arrangement assumed by 5 is
shown in Fig. 3. The isostructuralism between
the N-(p-chlorophenyl)mannopyranosylamine
and the m-chloro isomer 3 shows that the
crystalline environment of C-9 in this packing
arrangement is sufficiently uncrowded to al-
low the replacement of a hydrogen atom with
a chlorine atom without disrupting the molec-
ular packing. The fact that the o-chloro iso-
mer 5 assumes a unique packing arrangement
would suggest that the same cannot be said
for the environment of C-8 in the structure
assumed by 1–3; however, it is possible that a
polymorph of 5 isostructural with 1–3 could
exist and simply has not yet been obtained
under the crystallization conditions used here.
Although the overall packing arrangement of
5 is different from that of 1–3, a pair of
intermolecular contacts found in 1–3 and also
in 4, the O-3ꢀH···O-5 and O-6ꢀH···O-4 hydro-
gen bonds linking translationally related
molecules, are also found in 5. The hydrogen
bonding pattern of 5 includes a three-center
hydrogen bond (sum of the angles O-3ꢀH···O-
Fig. 3. Molecular packing in 5.
Fig. 4. Molecular packing in 6.
the a-axis of 4 was approximately twice as
long as the a-axes of the other compounds.
The data support a structure in which the
asymmetric unit of 4 contains two crystallo-
graphically independent molecules that differ
primarily in the orientations of their methoxyl
groups, as opposed to a cell half the size with
a disordered methoxy group. The two differ-
ent orientations may be the result of packing
considerations, the different twists about the
methoxyl CꢀO bond perhaps allowing the
most efficient packing of (or minimizing colli-
sions between) methoxyl groups (see Table 2
for relevant torsional angles). As it is, the
approaches between neighboring methoxyl
groups are close: O-7···C-13 (1−x, 1/2+y,
2, O-3ꢀH···O-5, and O-2···H···O-5:360°; 1.4
31
,
,
ABH···O-2 and H···O-5B2.85 A ).
Molecular packing in the o-methyl deriva-
tive 6 is shown in Fig. 4. As noted previously,
methyl groups can serve as isosteric replace-
ments for chlorine atoms and leave packing
arrangements unaffected; however, the pack-
ing arrangement of 6 is unique, different even
from that of the o-chloro compound 5. In
spite of the difference in packing, the O-
3ꢀH···O-5 and O-6ꢀH···O-4 hydrogen bonds
found in all the other mannopyranosylamines
are also found in 6. This is the only structure
among the mannosylamines we have examined
thus far in which the C-6ꢀO-6 side chain
,
1−z)=3.146(5) A; O-27···C-33 (2−x, −1/
,
2+y, 1−z)=3.072(4) A. Had these
methoxyl group orientations been identical,
only minor additional conformational adjust-
ments would be required to make the two

422
C.R. Ojala et al. / Carbohydrate Research 332 (2001) 415–427
assumes a conformation other than gt. This
fact may be further evidence that the pair of
translational contacts O-3ꢀH···O-5 and O-
6ꢀH···O-4 are important modes of intermolec-
ular interaction for mannopyranosylamines.
In the packing arrangement assumed by 6, the
translational O-6ꢀH···O-4 contact is main-
tained if the C-6ꢀO-6 side chain assumes the
gg rather than the gt conformation. This con-
formation places O-6 in a position to serve as
an acceptor in another hydrogen bond as well:
O-4ꢀH···O-6 (−1/2−x, 1−y, 1/2+z)=
10, although somewhat less weight can be
given to the hydrogen positions in 10 than to
those in the other structures (see Section 3).
The same hydrogen-bond pattern found in
7–11 is maintained in even the ‘different’
structure 12, for which the data support a
structure with two independent molecules in
the asymmetric unit (as in 4) as opposed to a
cell half the size and a structure with a disor-
dered aryl ring. If the torsional angles to the
aryl rings had been the same, with little addi-
tional change the molecules would have been
translationally related instead of crystallo-
graphically independent and 12 would have
been isostructural with 7–11.
Even such a potentially disruptive exchange
as a nitro group for a hydrogen atom in 11
causes no significant change in the packing
arrangement. In 11 the nitro group is isolated
from the hydrogen-bonding pattern estab-
lished by the monosaccharide hydroxyl
groups, so its presence in or absence from the
structure has little effect. Although we have
not investigated its optical properties, com-
pound 11 is a potential nonlinear optical ma-
terial. Connecting a p-nitroaniline group to
one enantiomer of a monosaccharide to form
the optically active glycosylamine is a strategy
guaranteed to place this polar group in the
noncentrosymmetric crystalline environment
required for nonlinear optical applications.32
The second harmonic generation efficiency of
a related compound, N-(4-nitrophenyl)ara-
binopyranosylamine, is reported to be ten
times that of urea.33 Optical properties and
other physical properties of 11 might be
modified in controlled fashion by cocrystalliz-
ing 11 with one or more of its isostructural
analogues 7–10.
,
2.666(2) A.
Compounds 7–11 assume the packing ar-
rangement shown for 11 in Fig. 5. The
molecules are linked pairwise at multiple
points by hydrogen bonds between molecules
related by screw-axial symmetry. The O-4 hy-
droxyl of a given molecule is positioned so
that it can serve as an H-bond donor to either
O-2 or O-3 of a neighboring screw-axially
related molecule or to both of these potential
acceptors. Similarly, O-6 of this same given
molecule is positioned so that it can serve as
an H-bond donor to either O-3 or O-4 or to
both of these acceptors in the same neighbor-
ing screw-axially related molecule. Both the
O-4 and O-6 interactions are potential three-
center hydrogen bonds, judging from the hy-
drogen···acceptor distances (generally shorter
,
than 2.85 A) and the angles (sum of
DꢀH···acceptor (1), DꢀH···acceptor (2), and
acceptor (1)···H···acceptor (2) angles:360°).
On the other hand, alternative interpretations
of the hydrogen bond patterns are possible; a
different donor–acceptor pattern is shown by
The tendency toward isostructuralism
among these mannopyranosylamines and
galactopyranosylamines reflects the strength
of the hydrogen-bonding interactions linking
monosaccharide moieties, interactions charac-
teristic of the sugar and so important in deter-
mining the packing arrangement that they
may be preserved from compound to com-
pound regardless of changes in the structure
of the aglycone. Even in 2-nitrophenyl 1-thio-
b-
D
-galactopyranoside,30 a structure different
Fig. 5. Molecular packing in 11.
(orthorhombic instead of monoclinic, a sulfur-

C.R. Ojala et al. / Carbohydrate Research 332 (2001) 415–427
423
2–3 drops of glacial HOAc had been added.
Crystals suitable for X-ray analysis could be
obtained by concentrating the solution to ap-
proximately 8 mL and recrystallizing the pow-
dery solid thus obtained from EtOH or by
simply allowing the reaction mixture to slowly
evaporate to dryness. Compound 1 was ob-
tained as thin colorless plates, mp 178–180 °C
(lit. 166–167 °C;34 2 as colorless flat needles,
mp 171–173 °C (lit. 187 °C16, 168–169 °C34); 3
as colorless prisms, mp 195–198 °C; 4 as color-
less sword-shaped crystals, mp 160 °C (lit.
150–152 °C34); 5 as colorless plates, mp 194–
196 °C; 6 as fine colorless needles, mp 171–
174 °C (lit. 167 °C16); 7 as colorless needles, mp
155 °C (lit. 150 °C16); 8 as colorless needles, mp
193–196 °C (lit. 184 °C16); 9 as colorless rods,
mp 170–173 °C; 10 as pale yellow needles, mp
162–164 °C; 11 as pale yellow, sword-shaped
crystals, mp 212–214 °C (lit. 219 °C15); and 12
as colorless needles, mp 152 °C (lit. 161 °C16).
Like those of the analogous N-phenyl-
mannopyranosylamine,20 crystals of 7 were
found upon examination under the microscope
to be hollow with solvent trapped inside. At-
tempts to trim these crystals to a size suitable
for X-ray data collection caused the solvent to
bubble and flow out of the crystal. An intact,
untrimmed crystal of 7 was used for data
collection; the existence of the solvent channel
did not appear to affect the quality of the
structure determination significantly.
X-ray crystal structure determinations.—A
summary of the crystal data, data collection
parameters, and refinement results is given in
Table 4. In all twelve structures the non-hydro-
gen atoms were refined anisotropically. The
best crystals of 1, 9, and 10 that could be
obtained for crystallographic analysis were
very small and thin, and the analyses suffered
from the combination of small crystal size and
large contribution of the halogen atom to the
scattering. Attempts to refine the positional
parameters of the hydrogen atoms in these
circumstances led to unreasonably short OꢀH
bond lengths. Subsequently for 1 and 9 the
CꢀH hydrogen atoms were placed in calculated
positions and the OꢀH and NꢀH hydro-
gen atoms were left in difference map
positions. For 10 the most reasonable results
Scheme 2. H-bonding interaction observed in 1–6 (top);
hypothetical corresponding interaction between glyco-
protein and an N-terminal peptide residue (bottom).
a
for-nitrogen exchange, and a different ring
position for the nitro group) from 7–12, three
of the four hydroxyl groups serve as H-bond
donors to the same atoms as in 7–12 and with
the same symmetry relationship (translational
for O-2ꢀH-2···O-6; screw-axial for O-4ꢀH-
4···O-3 and O-6ꢀH-6···O3). In the mannopyran-
osylamine series 1–6, the O-3ꢀH···O-5 and
O-6ꢀH···O-4 contacts between translationally
related molecules appear to be especially favor-
able interactions, being found in every struc-
ture examined and in different packing
arrangements. This raises the possibility that
other molecules with suitably positioned hy-
drogen-bond donor and acceptor atoms might
interact with a mannopyranosylamine in this
same manner preferentially (Scheme 2). These
small-molecule structures thus may serve as
useful models in the study of molecular recog-
nition in macromolecular systems such as gly-
coproteins and proteoglycans.
3. Experimental
Preparation of N-aryl-i-
osylamines.—Compounds 1–12 were prepared
by combining -mannose or -galactose (0.3
D
-glycopyran-
D
D
g) with an equimolar amount of aniline or
substituted aniline in 15 mL of EtOH to which

424
C.R. Ojala et al. / Carbohydrate Research 332 (2001) 415–427
Table 4
Crystal data, data collection parameters, and refinement results for 1–12
1
2
3
Formula
C12H16BrNO5
C13H19NO5
C12H16ClNO5
Formula weight
Crystal dimensions (mm)
Crystal system
Space group
334.17
269.30
289.72
0.24×0.22×0.04
monoclinic
P21
0.50×0.16×0.08
monoclinic
P21
0.36×0.20×0.08
monoclinic
P21
,
a (A)
6.537(1)
6.950(1)
14.799(1)
101.26(1)
659.5(2)
2
1.683
340
44.27
140.3
6.444(1)
6.752(1)
15.530(1)
96.56(1)
671.3(2)
2
1.332
288
8.59
140.2
6.472(1)
6.8199(9)
15.008(1)
101.510(9)
649.2(1)
2
1.482
304
27.82
140.3
,
b (A)
,
c (A)
i (°)
V (A )
3
,
Z
Dcalcd (g cm−3
F(000)
)
v(Cu Ka) (cm−1
2qmax (°)
)
Measured reflections
Unique reflections
Rint
2760
1274
0.034
2792
1274
0.025
2571
1165
0.031
Observed reflections [I\0.00|(I)]
Variables
2325
171
2327
187
2114
220
Trans. coefficients
0.6552–1.0000
0.9314–1.0000
3.33227×10−5
−0.19, 0.18
0.043; 0.029
0.6899–1.0000
1.20861×10−5
−0.44, 0.38
0.051; 0.034
Secondary extinction35
−3
,
Min, max in final difference map (e A
R; wR
)
−0.92, 0.58
0.065; 0.040
4
5
6
Formula
C13H19NO6
285.30
0.56×0.32×0.10
monoclinic
P21
C12H16ClNO5
289.72
0.44×0.28×0.06
monoclinic
C2
C13H19NO5
269.30
0.56×0.14×0.12
orthorhombic
P212121
Formula weight
Crystal dimensions (mm)
Crystal system
Space group
,
a (A)
12.947(2)
6.7299(9)
15.7880(9)
95.217(7)
1369.9(3)
4
1.383
608
9.31
140.2
14.8155(6)
5.6762(7)
17.363(1)
110.447(5)
1368.2(2)
4
1.406
608
26.40
140.2
11.458(3)
20.048(5)
6.032(3)
,
b (A)
,
c (A)
i (°)
V (A )
3
,
1385.7(6)
4
1.291
576
8.32
Z
Dcalcd (g cm−3
F(000)
)
v (Cu Ka) (cm−1
2qmax (°)
)
140.1
Measured reflections
Unique reflections
Rint
5491
2621
0.017
2744
1320
0.028
3035
1519
0.029
Observed reflections [I\0.00|(I)]
Variables
4795
391
2362
180
2538
188
Trans. coefficients
0.8716–1.0000
0.6645–1.0000
9.29949×10−6
−0.29, 0.28
0.046; 0.036
0.9654–1.0000
2.60792×10−6
−0.21, 0.26
0.058; 0.035
Secondary extinction35
−3
,
Min, max in final difference map (e A
R; wR
)
−0.23, 0.26
0.059; 0.035
7
8
9
Formula
C12H17NO5
C12H16ClNO5
C12H16BrNO5
Formula weight
Crystal dimensions (mm)
Crystal system
255.27
0.68×0.14×0.14
monoclinic
289.72
0.36×0.07×0.06
monoclinic
334.17
0.56×0.12×0.10
monoclinic

C.R. Ojala et al. / Carbohydrate Research 332 (2001) 415–427
425
Table 4 (Continued)
Space group
P21
P21
P21
,
a (A)
4.8224(6)
8.7142(8)
14.0550(6)
96.377(7)
586.99(8)
2
1.444
272
9.04
140.2
4.781(1)
8.5224(6)
15.9336(7)
96.955(9)
644.5(1)
2
1.493
304
28.18
140.2
4.7676(6)
8.5661(6)
16.1373(6)
96.694(8)
654.55(10)
2
1.695
340
44.61
140.1
,
b (A)
,
c (A)
i (°)
V (A )
3
,
Z
Dcalcd (g cm−3
F(000)
)
v(Cu Ka) (cm−1
2qmax (°)
)
Measured reflections
Unique reflections
Rint
2515
1115
0.017
2731
1207
0.032
2838
1255
0.030
Observed reflections [I\0.00|(I)]
2073
2243
2336
Variables
178
187
172
Trans. coefficients
0.8962–1.0000
1.17627×10−4
−0.14, 0.16
0.035; 0.035
0.9269–1.0000
7.55625×10−6
−0.21, 0.22
0.043; 0.022
0.8984–1.0000
3.27365×10−5
−0.57, 0.27
0.034; 0.033
Secondary extinction35
−3
,
Min, max in final difference map (e A
R; wR
)
10
11
12
Formula
C12H16INO5
381.17
0.44×0.06×0.06
monoclinic
P21
C12H16N2O7
300.27
0.56×0.28×0.07
monoclinic
P21
C13H19NO5
269.30
0.48×0.13×0.12
monoclinic
P21
Formula weight
Crystal dimensions (mm)
Crystal system
Space group
,
a (A)
4.768(2)
8.655(2)
16.438(1)
95.85(2)
674.8(2)
2
1.876
376
188.14
140.2
4.845(2)
8.361(1)
16.032(1)
97.74(2)
643.5(2)
2
1.550
316
11.11
140.2
9.628(1)
8.5347(6)
16.0070(8)
97.498(6)
1304.0(2)
4
1.372
576
8.84
140.3
,
b (A)
,
c (A)
i (°)
V (A )
3
,
Z
Dcalcd (g cm−3
F(000)
)
v(Cu Ka) (cm−1
2qmax (°)
)
Measured reflections
Unique reflections
Rint
2759
2264
0.026
2703
1193
0.029
5194
2440
0.031
Observed reflections [I\0.00|(I)]
Variables
2254
177
2208
237
4537
373
Trans. coefficients
0.5329–1.0000
0.8451–1.0000
0.9412–1.0000
1.25965×10−5
−0.28, 0.22
0.056; 0.032
Secondary extinction35
−3
,
Min, max in final difference map (e A
R; wR
)
−0.95, 1.23
0.065; 0.048
−0.17, 0.13
0.036; 0.035
,
For all twelve structures: T=298 K; diffractometer: Rigaku AFC6S; radiation: Cu Ka; u=1.54178 A; cell determination: 25
reflections (24 for 7), 45B2qB50°; data collection: MSC/AFC control software;36 scan mode: ꢀ/2q; structure solution:
SHELXS86;37 structure refinement: teXsan software package;38 decay correction: none for 1, 3–6, 8–12; 2.75% for 2, 1.46% for 7;
22
absorption corrections: psi scans;39 figures: ORTEPII
4F2obs/|2(Fo2bs); Rint=SSꢀŽFi2−F2ijꢀ/SmŽFi2.
;
R=SꢀꢀFobsꢀ−ꢀFcalcꢀꢀ/SꢀFobsꢀ; wR=[(Sw(ꢀFobsꢀ−ꢀFcalcꢀ)2/SwFo2bs
]
1/2; w=
were obtained by placing CꢀH hydrogen atoms
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OꢀH hydrogen atoms in difference map posi-
tions. The relatively large electron-density
peaks remaining in the difference map were
associated with the iodine atom. In 5 the O-2

426
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