Proton-acceptor properties and capability for mutarotation of some glucosylamines in methanol

Article abstract of DOI:10.1016/j.carres.2004.02.028

N-(m-Nitrophenyl)-β-D-glucopyranosylamine (Gln), N-(N-methylphenyl)- β-D-glucopyranosylamine (Glm), N-β-D-glucopyranosylpyrazole (Glp), and N-β-D-glucopyranosylimidazole (Gli) have been synthesized. Their basicity constants, pK_b, determined in methanol were, respectively, 14.99, 14.36, 15.04, and 9.74. The derivatives of secondary amines (Glm, Glp, and Gli) did not mutarotate in methanol in the presence of 3,5-dinitrobenzoic acid and hydrochloric acid. The heats of formation and entropies were calculated by the AM1 and PM3 methods for the glucosylamines and their cations under consideration of two plausible protonation centers. Thermodynamic parameters for the proton transfer in the reaction: glucosylamine+CH₃OH₂ ⁺=glucosylamineH⁺+CH₃OH were determined and the protonation center in the glucosylamine molecule was identified. The mechanism of mutarotation of the glucosylamines is discussed and the conclusion made that formation of an acyclic immonium cation is not a satisfactory condition for the reaction to proceed.

Full text of DOI:10.1016/j.carres.2004.02.028

Carbohydrate
RESEARCH
Carbohydrate Research 339 (2004) 1439–1445
Proton-acceptor properties and capability for mutarotation of
some glucosylamines in methanol
Kazimiera Smiataczowa, Jarosław Kosmalski, Andrzej Nowacki, Małgorzata Czaja
and Zygmunt Warnke*
Faculty of Chemistry, University of Gdansk, Sobieskiego 18, PL-80-952 Gdansk, Poland
Received 17 November 2003; received in revised form 9 February 2004; accepted 26 February 2004
Abstract—N-(m-Nitrophenyl)-b-
D
-glucopyranosylamine (Gln), N-(N-methylphenyl)-b-
D
-glucopyranosylamine (Glm), N-b-D-gluco-
pyranosylpyrazole (Glp), and N-b-
D
-glucopyranosylimidazole (Gli) have been synthesized. Their basicity constants, pKb, determined
in methanol were, respectively, 14.99, 14.36, 15.04, and 9.74. The derivatives of secondary amines (Glm, Glp, and Gli) did not
mutarotate in methanol in the presence of 3,5-dinitrobenzoic acid and hydrochloric acid. The heats of formation and entropies were
calculated by the AM1 and PM3 methods for the glucosylamines and their cations under consideratiþon of two plausible protonation
centers. Thermodynamic parameters for the proton transfer in the reaction: glucosylamine þ CH3OH2 ¼ glucosylamineHþ þ CH3OH
were determined and the protonation center in the glucosylamine molecule was identified. The mechanism of mutarotation of the
glucosylamines is discussed and the conclusion made that formation of an acyclic immonium cation is not a satisfactory condition for
the reaction to proceed.
ꢀ 2004 Elsevier Ltd. All rights reserved.
Keywords: Glucosylamines; Basicity constants; Mutarotation; Thermodynamic parameters
1. Introduction
presented. Accordingly, in the first step a proton is
attached to the heterocyclic oxygen atom, Oh, and the
conjugate acid formed is then converted to an acyclic
immonium cation, which subsequently generates a
variety of both cyclic and acyclic products. This mech-
anism was compatible with the results of investigation of
Glycosylamines derived from primary amines have been
found to readily undergo anomerization (a $ b) in acid
media.1–3 The rate of anomerization of N-arylglucosyl-
amines has been reported to be linearly related to bas-
icities of the parent amines and directly related to the
acidities of the catalysts.4 Methyloxonium ions turned
out to be the most potent catalysts as demonstrated by
the catalytic constant of the CH3OHþ2 ions, which
amounts to 1.26 · 106 dm3 molÀ1 minÀ1 being 6 · 106-fold
higher than the corresponding constants of benzoic acid
molecules.5 Consequently, the more readily the proton-
ation of a glycosylamine molecule occurs, the faster is
the isomerization reaction.
the mutarotation reaction of N-(p-chlorophenyl)-b-D-
glucopyranosylamine.9;10 However, if the formation of
the acyclic cation were a necessary condition for the
anomerization reaction, all glucosylamines irrespective
of the number of substituents in the parent amines
would undergo mutarotation.8;11 On the other hand,
there are also reports showing that N-glycosides of
secondary amines do not undergo mutarotation.12–14
Our studies have been aimed at the determination of
basicity constants of some glucosylamines derived from
secondary amines, investigation of their reactivities in
the presence of acidic catalysts, determination of their
protonation energies, and addressing the question of
formation of acyclic cations enabling mutarotation
reactions to occur.
In Scheme 1, literature views2;6–8 on catalytic influence
of acids on the course of the mutarotation reaction are
* Corresponding author. Fax: +48-58-3410357; e-mail: warnke@chemik.
chem.univ.gda.pl
0008-6215/$ - see front matter ꢀ 2004 Elsevier Ltd. All rights reserved.
doi:10.1016/j.carres.2004.02.028

1440
K. Smiataczowa et al. / Carbohydrate Research 339 (2004) 1439–1445
H
X
X
X
H
X
H
H
H
NR
H
O
2
OH
OH
O
NR
NR
NR
2
2
2
+H O
2
-HX
-H O
2
+HX
O
+H
-H
H,OH
H
H
O
OH
OH
NR
OH
NHR
2
2
CHO
X
Scheme 1. Mechanism of the mutarotation of glucopyranosylamines from Paulsen and Pflughaupt.2
25
exhibit small positive optical rotations, ½aŠ546, of +6.0
Glucosylamines have been found to bind not only
protons, but also Lewis acids.15 In this respect, the
results of this work are likely to contribute to better
understanding of the properties of glucosylamines,
which are candidates as ligands during our future
studies of their interaction with transition metal ions.
and +12.0 (c 0.46, MeOH), respectively. A quite oppo-
site initial optical rotation exhibits m-nitroaniline N-
25
546
glucoside with ½aŠ of À171 (c 0.60, MeOH), whereas
the value for N-methylaniline is À25.9 (c 0.5, MeOH).
The reactivity of N-arylglycosylamines has been
found to be dependent on the basicity of the parent
primary amines.4;11;18 The basicities of the glucosylam-
ines studied by the present authors were determined
in absolute methanol by the potentiometric titration
method.19;20 A plot of E1=2 versus pKb is a straight line
within a limited basicity range of the compounds only.
Straight line A in Figure 2 represents a relationship
between E1=2 and pKb for the stronger amines (pKb
covering the range 8.6–13.6; Table 1, nos 1–4). On the
basis of this relationship and the measured E1=2 values,
pKb ¼ 9:74 was determined for Gli. The weaker amines,
with pKb falling in the range 14.8–16.3 (nos 6–9) locate
themselves in straight line B. The pKb values of 14.36
and 15.04 were calculated from the equation of this line
for Glm and Glp, respectively. Attachment of the sugar
residue to an amine as well as the influence of the
2. Results and discussion
N-(m-Nitrophenyl)-b-
obtained by direct reaction of a-
roaniline in methanol.16;17 Secondary amines do not di-
rectly react with a- -glucose even in the presence of a
D
-glucopyranosylamine (Gln) was
D
-glucose with m-nit-
D
catalyst. Hence, Glm, Glp, and Gli were synthesized
from pentaacetylglucose through a multistep process.
Resulting products (Fig. 1) were carefully identified.
Thus, apart from elemental analysis, NMR and IR
spectroscopy and mass spectrometry were used for
identification.
The results have shown that all compounds are b
anomers. The N-glucosides of pyrazole and imidazole
HO
H
HO
H
H
H
O
O
HO
HO
HO
HO
N
N
H
H
OH
OH
H
NO
CH
3
2
H
O
H
H
H
Gln
Glm
HO
HO
H
H
H
H
O
N
HO
HO
HO
HO
N
N
N
H
OH
H
OH
H
H
H
H
Gli
Glp
Figure 1. N-(m-Nitrophenyl)-b-
D
-glucopyranosylamine (Gln), N-b-
D
-glucopyranosylpyrazole (Glp), N-b-D-glucopyranosylimidazole (Gli), and
N-(N-methylphenyl)-b- -glucopyranosylamine (Glm).
D

K. Smiataczowa et al. / Carbohydrate Research 339 (2004) 1439–1445
1441
B
400
7
9
8
6
350
300
250
200
150
100
50
4
3
A
2
1
8
9
10
11
12
pKb(MeOH)
13
14
15
16
Figure 2. Half-neutralization potential, E1=2, versus pKbðMeOHÞ. Parameters of equation A: E1=2 ¼ 55:1 Â pKb À 401:1, r ¼ 0:9994 and B:
E1=2 ¼ 7:99 Â pKb À 263:8, r ¼ 0:9961.
Table 1. The E1=2 values and basicity constants in water19;21;22 and in methanol19;23 at 25 ꢁC
19;21;22
19;23
No
Compound
pKbðH
E1=2
pKbðMeOHÞ
2OÞ
1
Imidazole
p-Toluidine
6.97
8.93
73.5
154
248.5
346.5
135
382
383
386
394
––
8.60
10.16
11.70
13.61
9.74
2
3
p-Chloroaniline
m-Nitroaniline
10.02
11.54
––
4
5
N-b-
D
-Glucopyranosylimidazole (Gli)
-glucopyranosylamine
-glucopyranosylamine (Gln)
6
N-(m-Bromophenyl)-b-
D
12.44
12.59
12.87
13.45
11.52
13.36
9.19
14.79
14.99
15.22
16.31
––
7
N-(m-Nitrophenyl)-b-
p-Nitroaniline
o-Nitroaniline
Pyrazole
D
8
9
10
11
12
13
14
15
N-b-D
-Glucopyranosylpyrazole (Glp)
384
––
15.04
10.51
14.29
––
m-Toluidyne
N-(m-Methylphenyl)-b-
N-Methylaniline
D
D
-glucopyranosylamine
12.06
9.2
––
––
––
N-(N-Methylphenyl)-b-
-glucopyranosylamine (Glm)
378.5
14.36
methanolic medium have been found to decrease the
basicities of the amines, the decrease being equal for
both the primary and secondary amines as demon-
strated by pKb values of m-nitroaniline and pyrazole in
water equal to 11.54 and 11.52, respectively, whereas the
N-glucosides of the amines in methanol have also low-
ered pKb values in methanol (14.99 and 15.04, respec-
the reaction is intricate9 and it proceeds during tens or
so minutes, whereas in a 1 · 10À2 M acid the equilibrium
is attained immediately, and after a few hours the color
of the solution turns red.25
N-b-D-Glucopyranosylpyrazole of the basicity com-
parable with that of Gln does not mutarotate under
comparable conditions. Even after 11 days the optical
rotation of a Glp solution with 3,5-dinitrobenzoic acid
did not change. No changes were also observed in
2.38 · 10À4 and 1 · 10À2 M HCl solutions during ten or
so days. A similar stability in acid solutions with no
mutarotation showed Glm. The much more basic Gli
(pKb ¼ 9:74) was not affected by these catalysts and
remained unchanged during several days. For compar-
ison, p-toluidine N-glucoside (pKb ¼ 14:08) undergoes
immediate mutarotation catalyzed by weak benzoic
acid, at an immeasurable rate.4
tively). Similarly, the pKbðH OÞ’s of m-toluidine and
2
N-methylaniline are respectively, 9.19 and 9.2, whereas
their glucosylamines have lowered pKb values in meth-
anol (14.29 and 14.36, respectively).
The N-(m-nitrophenyl)-b-D-glucosylamine undergoes
mutarotation in methanol. In the presence of
4.54 · 10À4 M 3,5-dinitrobenzoic acid the equilibrium is
attained within approximately 5 h. A plot of lnða1 À atÞ
versus t (Fig. 3) reveals the first kinetic order of
the reaction4;24 and the catalytic constant is
0.207 dm3 molÀ1 sÀ1. Hydrochloric acid is a more potent
catalyst. In a 2.38 · 10À4 M HCl solution the progress of
Studies on anomerization of N-arylglucosylamines
have shown that the rate of the reaction is directly

1442
K. Smiataczowa et al. / Carbohydrate Research 339 (2004) 1439–1445
0.5
0.0
-0.5
-1.0
-1.5
-2.0
-2.5
-3.0
0
50
100
150
t[min]
200
250
300
Figure 3. Time-dependent variation of the optical rotation of solution for the mutarotation of N-(m-nitrophenyl)-b-
D-glucopyranosylamine cata-
lyzed by a 4.54 · 10À4 M solution of 3,5-dinitrobenzoic acid.
related to the ease of protonation of a glucosylamines.
Bearing this in mind, we determined the heats and
entropies of formation of both the glucosylamines and
their cations formed by protonation of either the
nitrogen atom or the Oh atom in the ring (Table 2). In
addition, thermodynamic parameters were calculated
for gas phase protonation of four glucosylamines under
consideration of four plausible protonation centers
(Table 3).
As seen in Table 3, the preferred protonation center
in Gln is
a
heterocyclic oxygen atom DH0f ¼
À54:4 kcal molÀ1). Protonation of this atom results in
breaking the sugar ring this facilitating the change of
configuration of the C-1 atom as illustrated in Scheme 1.
The basicity of Glp is comparable with that of Gln,
but the proton is much more strongly bound with the
nitrogen atom (N-2) of the pyrazole molecule
Table 2. Heats of formation and entropies calculated using the AM1
and PM3 methods
(À51.1 kcal molÀ1
)
than with the ring oxygen
(À43.6 kcal molÀ1). In the molecule of Gli, the imidazole
nitrogen (N-3) is the strongest proton acceptor
(À69.6 kcal molÀ1). The lack of reactivity of the Glp and
Gli molecules is due to a stronger basicity of the nitro-
gen atom in the aglycon as compared to that of Oh.
Protonation of the latter would result in breaking the
sugar ring as shown in Figure 4, but this process is
energetically unfavorable.
Compound
AM1
PM3
H.O.F.
(kcal molÀ1
S
H.O.F.
(kcal molÀ1
)
)
(cal molÀ1 KÀ1
)
Gln
GlnNHþ
GlnOHþ
À208.0
À47.5
À54.0
112.3
113.0
112.9
À200.8
À38.5
À39.6
Glp
GlpNHþ
GlpOHþ
À162.3
À7.0
2.5
103.1
102.6
107.3
À162.2
À4.0
12.2
Also Glm, of basicity comparable with that of m-
toluidine N-glucoside does not mutarotate in spite of the
finding that the latter compound mutarotates smooth-
ly.4 In the case of Glm, Oh becomes first protonated
beyond any doubt. Protonation of the ring oxygen is
energetically favorable (À65.3 kcal molÀ1) and results in
breaking of the sugar ring (Fig. 4). This notwithstand-
Gli
GliNHþ
GliOHþ
À176.4
À37.5
À10.4
101.9
105.4
107.7
À179.8
À38.6
À0.6
Glm
GlmNHþ
GlmOHþ
À204.0
À53.7
À60.9
112.4
111.9
114.1
À189.8
À35.2
À37.1
Table 3. Thermodynamics of protonation of glucosylamines calculated using the AM1 and PM3 methods
Reaction
DHr0 (kcal molÀ1
)
Sr0 (cal molÀ1 KÀ1
)
G0r (kcal molÀ1
)
Gln þ CH3OHþ2 ¼GlnNHþ þ CH3OH
Gln þ CH3OHþ2 ¼GlnOHþ þ CH3OH
Glp þ CH3OHþ2 ¼GlpNHþ þ CH3OH
Glp þ CH3OHþ2 ¼GlpOHþ þ CH3OH
Gli þ CH3OHþ2 ¼GliNHþ þ CH3OH
Gli þ CH3OHþ2 ¼GliOHþ þ CH3OH
Glm þ CH3OHþ2 ¼GlmNHþ þ CH3OH
Glm þ CH3OHþ2 ¼GlmOHþ þ CH3OH
À47.9
À54.4
À53.1
À43.6
À69.6
À42.5
À58.1
À65.3
À0.7
À0.8
À1.9
2.8
À4l7.8
À54.2
À52.6
À44.4
À70.2
À43.8
À57.5
À65.4
2.0
4.3
À1.9
0.3

K. Smiataczowa et al. / Carbohydrate Research 339 (2004) 1439–1445
1443
Figure 4. Structures of compounds and their heats of formation expressed in kcal molÀ1
.
ing, the mutarotation of Glm does not occur. It can thus
be concluded that the formation of an acyclic glucosyl-
amine cation is unsatisfactory for changing the config-
uration of the anomeric carbon atom, that is for
mutarotation.
compounds of transition metal ions with N-glucosyl-
amines as ligands.
The calculated thermodynamic parameters (DHf0 and
3. Experimental
DG0f ) for the proton transfer in the reaction:
3.1. General methods
glucosylamine þ CH3OHþ $ glucosylamineHþ
2
NMR spectra were measured with a Varian Unity Plus
500 spectrometer at 500 MHz in CDCl3 or CD3OD
with Me4Si as the internal standard. Mass spectra were
recorded with a TRIO-3 VG MASLLAB spectrometer
with FABþ ionization mode. Infrared spectra were
recorded in KBr with a IFS66 ‘Bruker’ spectrophoto-
meter. The optical rotations were determined on a Jasco
J-20 polarimeter with the accuracy of 0.005ꢁ in a 2 dm
tubes at the D line of sodium at room temperature. The
measurements of mutarotation were carried out with the
accuracy of 0.01ꢁ, at 546 nm, on a Polamat A (C. Zeiss
Jena) polarimeter, at 25 0.1 ꢁC. Elemental analyses
were performed in a Carbo Erba Instruments Model
EA1108. Capillary melting points were taken and are
uncorrected. Reactions were monitored by thin-layer
chromatography (TLC) using aluminium-supported
plates with Silica Gel 60 (0.2 mm, E. Merck, Darmstadt,
þ CH3OH
enable to arrange the compounds in by their proton-
acceptor properties. These properties decline with
increasing acidity of the conjugate acids in the following
sequence: GliNHþ < GlmOHþ < GlmNHþ < GlnOHþ <
GlpNHþ < GlnNHþ < GlpOHþ < GliOHþ. In these
formulas indicated is the protonation of either the
nitrogen or oxygen (Oh) atom. The acidities of the
protonated weakly basic glucosylamines (GluOHþ,
GlpNHþ, and GlmOHþ) are linearly related to pro-
tonation enthalpies, pKa and DHr0 with correlation
coefficients r ¼ À1.
The established proton-acceptor (electron-donor)
properties of the glucosylamines will be helpful in our
further investigations into the formation of coordination

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K. Smiataczowa et al. / Carbohydrate Research 339 (2004) 1439–1445
0
Germany) in the CCl4–acetone solvent system 3:1 (v/v);
Evaporations were carried out under diminished pres-
sure at 30–40 ꢁC.
J5;6 1.98 Hz, H-60), 6.35–7.83 (H-pyrazole). FDMS: m=z
231 [Mþþ1].
3.2.3. 1-(2,3,4,6-Tetra-O-acetyl-b-
dazole (Ib). A mixture of 1-bromo-2,3,4,6-tetra-O-acet-
yl- -glucopyranose (2.4 g, 6 mmol), imidazole (1 g,
D-glucopyranosyl)imi-
3.2. Reagents
D
MeOH was first dried over Na2SO4 and then magnesium
methoxide and distilled.26 To remove basic impurities,
0.4 g of tartaric acid was added per 1 L of the solvent
and distillation was repeated.27 Finally, the solvent was
distilled through a Widmer column and a fraction
boiling strictly at the bp of pure MeOH, that is 65 ꢁC/
1013 hPa,9 was collected. Dioxane were purified by using
procedures reported in the literature.26
15 mmol), and dioxane (40 mL) was refluxed for 1.5 h.
During the heating imidazole hydrobromide fell out.
The dioxane layer was decanted and the solvent was
distilled off under reduced pressure. The residue was
dissolved in CHCl3. The chloroformic solvent was wa-
shed with dilute ammonia followed by water and dried
over MgSO4. Recrystallization from MeOH gave nee-
21
D
dles (1 g, 41%): mp 210–212 ꢁC; ½aŠ À7.3 (c 1.5,
CHCl3); Rf 0.75; IR m 1738.3, 1280 (C@O ester), 1236.8
1
(C–O–C ether); H NMR (CDCl3): d 5.33 (d, 1H, J1;2
3.2.1. 1-(2,3,4,6-Tetra-O-acetyl-b-
azole (Ia). To a solution of 1-bromo-2,3,4,6-tetra-O-
acetyl-N- -glucopyranose (1.23 g, 3 mmol), and pyraz-
D-glucopyranosyl)pyr-
6.54 Hz, H-1), 5.34 (t, 1H, J2;3 10.8 Hz, H-2), 5.32 (t, 1H,
J3;4 8.6 Hz, H-3), 5.24 (t, 1H, J4;5 10.2 Hz, H-4), 3.93 (m,
D
0
1H, J5;6 4.94 Hz, H-5), 4.28 (dd, 1H, J5;6 2.2 Hz, H-6),
ole (0.23 g, 3.3 mmol) in a mixture nitromethane (17 mL)
and toluene (17 mL) Hg(CN)2 (0.76 g, 3 mmol) was
added. The mixture was stored for 15 h at room tem-
perature. After removal of the solvents under reduced
pressure, the residue was dissolved in chloroform
(200 mL) and filtered. The chloroformic solution was
washed with a 1 M KI solution, water, then dried with
MgSO4, and concentrated. The product was crystallized
4.16 (dd, 1H, J6;6 12.65 Hz, H-60), 2.09, 2.07, 2.02, and
0
1.88 (each 3H, s, OAc), 7.63–7.09 (H-imidazole); 13C
NMR (CDCl3): 83.91 (C-1), 70.80 (C-2), 73.13 (C-3),
68.06 (C-4), 75.15 (C-5), 61.92 (C-6), 116.99–136.87 (C-
imidazole), 20.34–20.89 (OAc), 168.88–170.73 (C@O).
FDMS: m=z 399 [Mþþ1]. Anal. Calcd for C17H22N2O9
(398.36): C, 51.26; H, 5.57; N, 7.03. Found: C, 51.36; H,
5.59; N, 6.83.
from MeOH to give 1-(2,3,4,6-tetra-O-acetyl-b-D-glu-
21
D
copyranosylpyrazole (0.69 g, 58%): mp 136–137 ꢁC; ½aŠ
3.2.4. 1-b-D-Glucopyranosylimidazole (Gli). To a solu-
À6.4 (c 1, CHCl3); Rf 0.36; IR m 1753.8 (C@O), 1229.6
tion of Ib (0.14 g, 0.35 mmol) in abs MeOH (2.4 mL)
Et3N(0.15 mL, 1.09 mmol) was added. The mixture was
stored at room temperature; no 1-(2,3,4,6-tetra-O-acet-
1
(C–O–C), 1318.5 (C–N); H NMR (CDCl3): d 5.56 (d,
1H, J1;2 8.78 Hz, H-1), 5.59 (t, 1H, J2;3 9.02 Hz, H-2),
5.37 (t, 1H, J3;2 9.02 Hz, H-3), 5.26 (t, 1H, J4;3 9.75 Hz,
yl-b-
After evaporation to dryness the product was crystal-
lized from MeOH to give 1-b- -glucopyranosylimidaz-
D-glucopyranosyl)imidazole was detected (TLC).
0
H-4), 3.95 (m, 1H, J5;4 10.11 Hz, H-5), 4.30 (dd, 1H, J6;6
0
12.43 Hz, J5;6 4.39 Hz, H-6), 4.15 (dd, 1H, J5;6 1.95 Hz,
D
21
H-60), 2.08, 2.07, 2.04, and 1.86 (each 3H, s, OAc), 6.35–
7.62 (H-pyrazole); 13C NMR (CDCl3): d 87.30 (C-1),
70.45 (C-2), 73.40 (C-3), 68.16 (C-4), 74.74 (C-5), 61.98
(C-6), 107.55–140.98 (C-pyrazole), 20.42–20.91 (OAc),
169.12–170.80 (C@O). FDMS: m=z 399.3 [Mþþ1]. Anal.
Calcd for C17H22N2O9 (398.36): C, 51.26; H, 5.57; N,
7.03. Found: C, 51.17; H, 5.56; N, 6.08.
ole (57%); mp 216–219 ꢁC, ½aŠ +13.6 (c 1.5, CHCl3),
D
25
½aŠ +12.0 (c 0.46, MeOH); Rf 0; IR (KBr); m 3400 and
546
3200 (OH); 1H NMR (CD3OD): d 5.19 (d, 1H, J1;2
8.79 Hz, H-1), 3.60 (t, 1H, J2;3 9.15 Hz, H-2), 3.49 (t, 1H,
J
3;4 8.42 Hz, H-3), 3.47 (t, 1H, J4;5 10.2 Hz, H-4), 3.51 (m,
0
1H, J5;6 5.13 Hz, H-5), 3.71 (dd, 1H, J5;6 1.83 Hz, H-6),
3.88 (dd, 1H, J6;6 12.07 Hz, H-60), 6.99–7.85 (H-imid-
0
azole); 13C NMR (CDCl3): d 87.67 (C-1), 74.79 (C-2),
78.79 (C-3), 71.20 (C-4), 81.05 (C-5), 62.66 (C-6),
119.20–138.23 (C-imidazole). FDMS m=z 231 [Mþþ1].
Anal. Calcd for C9H14N2O5 (230.22): C, 46.95; H, 6.13;
N, 12.16. Found: C, 46.83; H, 6.44; N, 11.92.
3.2.2. 1-b-D-Glucopyranosylpyrazole (Glp). To a solution
of Ia (0.217 g, 0.55 mmol) in abs MeOH (2.4 mL) Et3N
(0.15 mL, 1.09 mmol) was added. The mixture was
stored at room temperature; no 1-(2,3,4,6-tetra-O-acet-
yl-b-
After evaporation to dryness the product was crystal-
lized from MeOH to give 1-b- -glucopyranosylpyrazole
D-glucopyranosyl)pyrazole was detected (TLC).
3.2.5. N-(m-Nitrophenyl)-b-D-glucopyranosylamine (Gln).
D
This was synthesized by refluxing a solution of 5.4 g
(27 mmol) of glucose p.a. and 4.5 g (30 mmol) of previ-
ously steam-distilled m-nitroaniline in 40 mL of
MeOH.11 On the next day, the precipitate was washed
with diethyl ether, dried, and recrystallized from ca.
50 mL of 96% ethanol p.a. After drying in an open
vessel, its mp was 173–175 ꢁC and the initial specific
21
25
(85.7%): mp 216–219 ꢁC; ½aŠ +3.18 (c 1, MeOH), ½aŠ
D
546
+6.0 (c 0.46, MeOH); Rf 0; IR m 3400 and 3200 (OH); 1H
NMR (CD3OD): d 5.26 (d, 1H, J1;2 9.12 Hz, H-1), 3.90
(t, 1H, J2;3 8.73 Hz, H-2), 3.47 (t, 1H, J3;4 9.55 Hz, H-3),
0
3.52 (t, 1H, J4;5 8.33 Hz, H-4), 3.49 (t, 1H, J5;6 4.76 Hz,
0
H-5), 3.69 (dd, 1H, J6;6 12.10 Hz, H-6), 3.86 (dd, 1H,

K. Smiataczowa et al. / Carbohydrate Research 339 (2004) 1439–1445
1445
25
D
25
546
rotation was: ½aŠ À144 (c 0.58, MeOH) ½aŠ À171 (c
References
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0.60, MeOH); Rf 0; H NMR (CD3OD): d 4.60 (d, 1H,
J1;2 8.4 Hz, H-1), 3.37 (t, 1H, J2;3 8.4 Hz, H-2), 3.48 (t,
1H, J3;4 8.8 Hz, H-3), 3.36 (t, 1H, J4;5 8.4 Hz, H-4), 3.43
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Acknowledgements
This research was supported by the Polish State Com-
mittee for Scientific Research under grant BW/8000-5-
0231-3.
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