Synthesis of α- and β-d-glucopyranosyl triazoles by CuAAC 'click chemistry': reactant tolerance, reaction rate, product structure and glucosidase inhibitory properties

Article abstract of DOI:10.1016/j.carres.2010.03.041

Cu^I-catalysed azide alkyne 1,3-dipolar cycloaddition (CuAAC) 'click chemistry' was used to assemble a library of 21 α-d- and β-d-glucopyranosyl triazoles, which were assessed as potential glycosidase inhibitors. In the course of this work, diff

Full text of DOI:10.1016/j.carres.2010.03.041

Carbohydrate Research 345 (2010) 1123–1134
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Carbohydrate Research
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Synthesis of
a- and b-D-glucopyranosyl triazoles by CuAAC ‘click chemistry’:
reactant tolerance, reaction rate, product structure and glucosidase
inhibitory properties
Simone Dedola a, David L. Hughes b, Sergey A. Nepogodiev a, Martin Rejzek a, Robert A. Field a,
*
a Department of Biological Chemistry, John Innes Centre, Colney Lane, Norwich, NR4 7UH, UK
b School of Chemistry, University of East Anglia, Norwich, NR4 7TJ, UK
a r t i c l e i n f o
a b s t r a c t
CuI-catalysed azide alkyne 1,3-dipolar cycloaddition (CuAAC) ‘click chemistry’ was used to assemble a
library of 21 - and b- -glucopyranosyl triazoles, which were assessed as potential glycosidase inhib-
itors. In the course of this work, different reactivities of isomeric - and b-glucopyranosyl azides under
CuAAC conditions were noted. This difference was further investigated using competition reactions
and rationalised on the basis of X-ray crystallographic data, which revealed significant differences in
Article history:
Received 5 March 2010
Received in revised form 25 March 2010
Accepted 31 March 2010
Available online 4 April 2010
a-
D
D
a
bond lengths within the azido groups of the
ence for perpendicular orientation of the sugar and triazole rings in both the
the solid state. The triazole library was assayed for inhibition of sweet almond b-glucosidase (GH1) and
yeast -glucosidase (GH13), which led to the identification of a set of glucosidase inhibitors effective in
the 100 M range. The preference for inhibition of one enzyme over the other proved to be dependent on
the anomeric configuration of the inhibitor, as expected.
a
- and b-anomers. Structural studies also revealed a prefer-
Keywords:
Click chemistry
a-D-Glucopyranosyl azide reactivity
Microwave
Triazole
Glucosidase inhibitor
a
- and b-glucosyl triazoles in
a
l
Ó 2010 Elsevier Ltd. All rights reserved.
1. Introduction
a- and b-glycosidases from various sources and showed only weak
inhibitory activity.17 Compounds 4a–4c were synthesised19 using
Glycoside hydrolases are involved in a large number of natural
processes related to carbohydrate metabolism. Detailed knowledge
of the mechanisms1 that these enzyme use to hydrolyse glycosidic
bonds of complex carbohydrates will facilitate the search for new
inhibitors,2,3 which is directly relevant to the discovery of new
therapeutics.4 During the last few years there has been increasing
interest in the use of the CuI-catalysed azide-alkyne cycloaddition
reaction (CuAAC), an example of so-called ‘click chemistry’,5,6 in
the field of carbohydrate research.7,8 This reaction has been used
to assemble mimics of oligosaccharides and glycopeptides,7–12 as
well as glycoclusters and dendrimers;13,14 it has also found appli-
cations in in vivo imaging of glycoconjugates.15,16 Several attempts
have been made to utilise click chemistry for the synthesis of po-
tential glycosidase inhibitors.17–19 For instance, b-linked 1-glyco-
syl-4-phenyltriazoles 1 and 2 (Fig. 1), prepared from b-glycosyl
azides and phenylacetylene, were assessed for inhibitory activity
against three different glycosidases.18 Compound 1 displayed 48%
inhibition of the bovine liver galactosidase activity at 0.24 mM
concentration, but in general the inhibitory activity of compounds
1 and 2 was weak. A series of acarbose-like pseudo-oligosaccha-
rides, for example triazole derivative 3, was assayed against
‘click chemistry’ in order to combine two distinct classes of
HO
HO
OH
O
OH
O
N
N
N
N
N
N
HO
HO
OH
OH
1
2
OH
O
HO
HO
HO
N
HO
O
O
2
N
N
HO
OH
O
OH
O
OH
O
HO
OH
3
O
HO
OH
OH
H
OH
N
N
O
HO
HO
n
N
OH
N
4a n = 2, 4b n = 3, 4c n = 4
* Corresponding author. Tel.: +44 1603 450720.
E-mail address: rob.field@bbsrc.ac.uk (R.A. Field).
Figure 1. Potential glycosidase inhibitors synthesised using ‘click chemistry’:
glucoside 1, galactoside 2, acarbose mimic 3 and MetAP2 II inhibitors 4.
0008-6215/$ - see front matter Ó 2010 Elsevier Ltd. All rights reserved.
doi:10.1016/j.carres.2010.03.041

1124
S. Dedola et al. / Carbohydrate Research 345 (2010) 1123–1134
N
N
N
N
N
N
O
N
N
OH
N
R
R
R
5a R = β-D-Glcp
5b R = α-D-Glcp
6a R = β-D-Glcp
6b R = α-D-Glcp
7a R = β-D-Glcp
7b R = α-D-Glcp
N
N
N
N
N
N
N
N
H
N
O
NH2
OH
O
N
N
N
N
R
R
R
R
O
O
O
8a R = β-D-Glcp
8b R = α-D-Glcp
9a R = β-D-Glcp
9b R = α-D-Glcp
10a R = β-D-Glcp
10b R = α-D-Glcp
11a R = β-D-Glcp
11b R = α-D-Glcp
O
N
N
N
N
N
N
N
N
OH
N
OH
N
N
N
N
β-D-Glcp
β-D-Glcp
β-D-Glcp
β-D-Glcp
β-D-Glcp
O
12
13
14
15
N
N
N
N
N
N
OH
OH
OH
N
N
N
β-D-Glcp
β-D-Glcp
O
16
17
18
Figure 2. Structures of target glucopyranosyl triazoles.
therapeutic agents—iminosugars and aryl-triazoles—which can
interfere with both glycosidases and methionine aminopeptidase
involved in angiogenesis.20,21
on the procedure first described by Sharpless30 that involves 0.25–
0.5 M reactants, 0.01 mol equiv of CuSO4 plus 0.1 mol equiv of so-
dium ascorbate (NaAsc) as a catalyst, in 1:1 t-BuOH/H2O solvent
mixture at room temperature. Testing these conditions for cou-
The approach adopted in the present work was based on a sim-
ple assumption that new glucosidase inhibitors can be identified by
screening libraries of glucosides having variable aglycones.22–27
Utilisation of ‘click chemistry’ for building libraries of this type
should allow one to overcome common synthetic challenges asso-
ciated with the preparation of O- or C-glycosides and make it pos-
sible to incorporate a wide variety of functional groups into the
aglycone portion of the glucopyranoside analogues. In this study
we have used the CuAAC reaction of glucopyranosyl azide building
blocks, both acetylated and deprotected, with assorted commer-
cially available alkynes possessing lipophilic, hydrophilic, acidic
or basic functionalities. The presence of these functional groups
provides an opportunity to probe interactions of putative inhibi-
tors with the active site while the relevance of the anomeric con-
figuration can be explored using compounds synthesised by
pling between peracetylated b-D
-glucopyranosyl azide 1931 and
propargyl alcohol revealed a low conversion to the desired product,
apparently as a result of the limited solubility of acetylated gluco-
pyranosyl azides in the chosen reaction medium. Therefore two
variations of these conditions were used (referred to as Methods
A and B), which allowed significant improvement of the cycloaddi-
tion yields of the target products. In Method A the reactions were
conducted at 70 °C (cf. Ref. 32) and the conversion of 19 into 1,4-
substituted triazoles was complete in 10 min, affording single
regioisomers 21, 22 and 24 (as judged by 1H NMR spectroscopy)
Table 1
Synthesis of b-D-glucopyranosyl triazoles 20–24 and 5a–11a
CuAAC of the same set of alkynes and either a- or b-glucopyranosyl
OR2
O
OAc
O
N
N
azide. A small library of prospective glucopyranosyl triazole-based
glycosidase inhibitors assembled using the CuAAC reaction (Fig. 2)
was screened against the cognate and non-cognate GH1
R
R2O
R2O
AcO
AcO
N3
N
R1
i
OR2
20-24
OAc
R2 = Ac
R2 = H
19
sweet almond b-glucosidase and GH13 yeast
are readily available and well-characterised model glucosidases.
The different reactivities of - and b-glucopyranosyl azides to-
a-glucosidase, which
ii
5a-9a
iii
a
10a-11a R2 = H
wards the CuAAC reaction, which was noted in recent work from
R1
Compound (yield, %)
this group,28 are also discussed in more detail.
–CH2OCHPh2
–Ph
–CH2OH
20B (98)
21A (97)
22A (99)
23B (95)
24A (70)
5a (88)
6a (94)
7a (92)
8a (91)
9a (95)
10a (91)
11a (92)
2. Results and discussion
–CH2NHCO2CMe3
–CO2Me
2.1. Synthesis of glucopyranosyl triazoles
–CH2NH2
–CO2H
Since the discovery of the CuAAC reaction29,30 a large number of
different reaction conditions and various forms of Cu(I) catalyst
have been reported.6 For our purpose, we adopted a method based
(i) CuAAC conditions: AMethod A; BMethod B; (ii) NaOMe–MeOH; (iii) CH2Cl2–TFA
9:1 (for 10a) or aq 1 M NaOH for (11a).

S. Dedola et al. / Carbohydrate Research 345 (2010) 1123–1134
1125
Table 3
in high yield (>90%) and purity. In Method B, the same concentra-
b-Glucopyranosyl triazoles 12–18
tions of reagents were used, and the same catalytic couple of
CuSO4/NaAsc, but a microwave reactor operating at 70 °C was em-
ployed and DMF was used as a solvent, as first suggested by Kha-
netskyy.33 This method has the advantage of short reaction times
and it has the potential for automation34—key features for the ra-
pid assembly of compound libraries. Some adjustment of reaction
time was required for individual reactants to avoid product decom-
position, which was easily monitored by TLC. Generally CuAAC
reactions are characterised by good tolerance of functional groups,
but for some functionalities application of protecting groups
proved necessary. For example, unprotected amines inhibit CuAAC
reactions, apparently by destabilising the oxidation state of
catalytic CuI by ligation.35 Thus in the synthesis of aminomethyl-
ene-triazole derivative 10a it was necessary to use Boc-protected
propargyl amine. Incompatibility with CuAAC reaction conditions
was also noticed in synthesis of carboxylic acid derivative 11a from
propiolic acid; the problem was overcome by using the methyl es-
ter as a temporary protecting group. The preparation of the first
small library of 1,4-substituted b-glucopyranosyl triazoles (Table 1)
was completed by removal of protecting groups which included
NaOMe-catalysed de-O-acetylation for all compounds, with
additional acid-catalysed cleavage of the Boc group in 23 and
base-catalysed hydrolysis of methyl ester 24.
OH
OH
O
N
N
O
CuI
HO
HO
HO
N3
N
HO
R
R
OH
OH
12-18
31
R
Compound (yield, %)
–CH2Ph
–CH2NPhth
12 (32)
13 (80)
14 (28)
15 (82)
16 (68)
17 (92)
18 (50)
–CH2CH(Me)OH
–CH(OH)CH2Me
–CH2CH2CH2OH
–CH2CH2CH2CH2OH
–CH2CH2CO2H
large positive
D(dC4–dC5) values (ca. 26 ppm) for triazole carbon
atoms in 13C NMR spectra.39 1H NMR spectra of the majority of tri-
azole derivatives showed signals with a chemical shift at d 8.00–
8.50 ppm, which is typical for the 1,4-substituted triazole ring. In
some cases triazole proton signals were less useful diagnostically,
falling in the range reported for 1,5-substituted triazoles (d
ꢀ7.70 ppm).39,40
The same set of alkynes as used in preparation of b-glucopyran-
A more direct approach to carbohydrate-containing triazoles
can be achieved by the direct reaction of unprotected sugar azides.
Clearly the synthetic procedure should be highly efficient in order
to generate products which do not require the laborious purifica-
tion that is often associated with unprotected carbohydrate deriv-
atives. CuAAC reactions satisfy these criteria, as demonstrated in
parallel synthesis with unprotected starting materials coupled,
without purification, with direct screening of products for biologi-
cal activity.41–44 Typical protocols for CuAAC coupling of water sol-
uble reagents30 (0.01 mol equiv CuSO4 and 0.1 mol equiv NaAsc in
1:1 t-BuOH–H2O) were found to be suitable for the rapid prepara-
tion of glucopyranosyl triazoles, such as 12 and 13, in a microtiter
plate format at 40 °C. However, the utility of this procedure was
hampered by the necessity for NaAsc/CuSO4 removal from the
reaction mixture. An alternative catalytic system which generates
CuI by the in situ reaction of CuSO4 with copper turnings30 was
found to be advantageous as the inorganic catalyst components
are easily separated from products by filtration through a short
osyl triazoles 5a–11a was applied for syntheses of the isomeric
glucopyranosyl triazoles 5b–11b (Table 2), starting from peracety-
lated -glucopyranosyl azide 25. This building block was obtained
in 60% yield by reacting 2,3,4,6-tetra-O-acetyl-b- -glucopyranosyl
a-
a
D
chloride36 with Me3SiN3 in the presence of Bu4NF in THF.28,37,38
CuAAC reactions were carried out in a microwave reactor at
70 °C with CuSO4/NaAsc as a catalyst and DMF as a solvent (Meth-
od B as above). All the target compounds were synthesised in high
yield and purity (Table 2), but completion of the cycloaddition re-
quired longer reaction time than in similar reactions with b-gluco-
pyranosyl azide (vide infra). All acetylated products were
deprotected using standard conditions similar to those described
for preparation of b-glucopyranosyl isomers 5a–11a.
The structure and purity of acetylated (20–24 and 26–30) and
deprotected glucopyranosyl triazoles (5a,b–11a,b and 12–18) were
unequivocally confirmed by NMR spectroscopy and ES mass spec-
trometry data. In particular, the 1,4 regioselectivity of the cycload-
dition reaction was confirmed in all the cases by characteristic
plug of silica gel. In this case, reactions between b-D-glucopyrano-
syl azide 31 and selected alkynes were carried out in a 3:2:5 mix-
ture of H2O–EtOH–t-BuOH42 for 48 h at room temperature,
resulting in triazoles 12–18 (Table 3). Relatively low yields in some
of these reactions can be attributed to loss of the material on silica
gel purification. The purity of each product was confirmed by 1H
NMR spectroscopy and mass spectrometry, and glucopyranosyl tri-
azole derivatives 12–18 were used directly for evaluation of their
glycosidase inhibitory activity.
Table 2
Synthesis of
a-D-glucopyranosyl triazoles 5b–11b
OR2
O
R2O
R2O
OAc
O
R
R2O
AcO
AcO
N
i
N
AcO
N3
N
25
R1
2.2. Relative reactivity of
a- and b-glucopyranosyl azides under
26-30
5b-9b
R2 = Ac
R2 = H
CuAAC reaction conditions
ii
iii
10b-11b R2 = H
The above-mentioned experiments highlighted the impact of
glycosyl azide anomeric configuration on the rate of CuACC reac-
tions, though final yields were high for both anomeric series. While
reactions with b-glucopyranosyl azide were typically complete in
R1
Compound (yield, %)
–CH2OCHPh2
–Ph
–CH2OH
–CH2NHCO2CMe3
–CO2Me
–CH2NH2
26 (99)
27 (63)
28 (60)
29 (94)
30 (96)
5b (90)
6b (99)
7b (94)
8b (99)
9b (99)
10b (99)
11b (94)
10–45 min, similar reactions with
a-glucopyranosyl azide often re-
quired 45–120 min. The lower reactivity of
a-glycopyranosyl
azides has been observed previously by Wilkinson et al.,45
although the comparison was indirect since the glucopyranosyl
azides studied had different protecting groups (acetates vs benzyl
ethers). In order to rationalise the difference in reactivity of
–CO2H
(i) CuAAC conditions: Method B; (ii) NaOMe–MeOH; (iii) CH2Cl2–TFA 9:1 (for 10b)
or aq 1 M NaOH for (11b).
b- and
a-glucopyranosyl azides towards the CuAAC reaction, we

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S. Dedola et al. / Carbohydrate Research 345 (2010) 1123–1134
Table 4
as a result of a partial negative charge on atom N(11), which plays
a crucial role in the mechanism of the CuAAC reactions, consistent
with results from DFT calculations.49
Interatomic distances (Å) for CN3 fragment in glycosyl azides 19 and 25a
b-Azide 19
a-Azide 25
Direct evidence for the lower reactivity of the
a- compared to
C(1)–N(11)
N(11)–N(12)
N(12)–N(13)
1.460 (2)
1.243 (2)
1.119 (3)
1.510 (3)
1.165 (3)
1.195 (4)
the b-glucopyranosyl azide was obtained from a competition reac-
tion between equimolar 19, 25 and propargyl alcohol (Scheme 1).
The reaction was run in the microwave under conditions discussed
earlier (Method B) and the composition of the reaction mixture
was analysed after 15 min. Characteristic J1,2 coupling constants
for the anomeric H-1 signal in glucopyranosyl triazoles (6.0 and
a
Atom numbering for C(1)–N(11)–N(12)–N(13) fragment is adapted from the
original publications.28,46
9.0 Hz for a- and b-anomer, respectively) allowed straightforward
identification of these signals (d 6.36 ppm for
a-anomer 28 and d
OAc
OAc
5.89 ppm for b-anomer 22) and complete assignment of the 1H
O
O
AcO
AcO
AcO
NMR spectrum of the mixture. Integration of sugar H-1 signals
and triazole H-5 signals (d 7.66 and 7.89 for
N
N
N
N
N
N
AcO
(11)(12)(13)
(11)(12)(13)
a- and b-anomers,
AcO
AcO
OAc
respectively) indicated that - and b-glucopyranosyl triazoles were
a
19
formed in an approximately 1:3 ratio, confirming the greater reac-
tivity of the b-configured azide.
OAc
2.3. X-ray crystal structure of glucopyranosyl triazoles 24 and
27
O
O
AcO
AcO
AcO
AcO
AcO
AcO
N
N
N
N
N
N
(11) (12) (13)
(11)(12)(13)
Ahead of investigating the glycosidase inhibitory properties of
our library of glycosyl triazoles we sought to gain some insight into
their structure, in particular the relative orientation of the sugar
and triazole rings. X-ray crystallographic studies were therefore
conducted on two representative glucopyranosyl triazoles having
25
Figure 3. Resonance structures for
a
- and b-glucopyranosyl azides.
b- and
a-anomeric configurations, namely compounds 24 and 27
(Fig. 4A and B, respectively). The planes of triazole and glucopyra-
nose rings of these molecules in the solid state were found to be
nearly perpendicular to each other, with the triazoles occupying
the C(1),C(4),O(4) plane bisecting the pyranose ring. The torsion
angle H(1)–C(1)–N(11)–N(12) is close to 180° for both b-isomer
OAc
OAc
O
O
AcO
AcO
N3
+
AcO
AcO
AcO
OAc
19
N3
25
24 and a-isomer 27 resulting in orientation of the triazole nitrogen
CuI
HO
atoms as shown in Figure 5. Comparison of the crystallographic
parameters of 24 and 27 with X-ray data of known b-glucopyran-
osyl triazole derivative 2250 revealed similarity of the geometrical
parameters for the glucopyranosyl fragments of these molecules,
all of which exist in the usual 4C1 chair conformation with minimal
distortion. The triazole ring of 22 occupies the same C(1),C(4),O(4)
plane of the molecule as in 24 but the triazole nitrogens in 22 are
facing in the opposite direction to that in b-glucopyranosyl triazole
24, as shown in Figure 4. In these examples, the perpendicular ori-
entation of the sugar and triazole rings is to be expected on steric
grounds. The difference between C(1)–N(11) bond lengths in glu-
copyranosyl triazoles 24 (1.449(2) Å) and 27 (1.463(3) Å) is small,
suggesting a limited influence of the anomeric effect on the
structure of these molecules. The lengths of the analogous bonds
OAc
O
AcO
AcO
OAc
OH
AcO
O
N
AcO
+
N
N
N
AcO
N
OAc
N
22
28
OH
Scheme 1. Competition experiment between b- and
a
-glucopyranosyl azides 19
and 25 in the presence of propargyl alcohol. Reagents and conditions: 1 equiv 19,
1 equiv 25, 0.05 equiv CuSO4; 0.1 equiv NaAsc, MW 70 °C; 15 min. The ratio
between b- and a-glucopyranosyl triazoles in the products mixture 22:28 = 3:1.
in precursors b-glucopyranosyl azide 19 (1.460(2) Å)46 and
a-
elucidated the X-ray crystal structure of the starting
a
-azide 2528
glucopyranosyl azide 2528 (1.510 (3) Å) suggest that the influence
of the anomeric effect is much stronger for the electronegative
azide group than for the triazoles.
and compared it to the known crystal structure of the correspond-
ing b-azide 19.46 This comparison revealed that acetylated gluco-
pyranose rings of 19 and 25 are very similar, except for the
anomeric azido groups having different configurations (axial vs
equatorial). In addition, the interatomic distances within the
C(1)–N(11)–N(12)–N(13) fragment (Table 4 and Fig. 3) are in keep-
ing with the expected influence of the anomeric effect.47,48 The
C(1)–N(11) distance in 19 is longer than the corresponding dis-
tance in 25; the terminal N(12)–N(13) bond is shorter than the in-
2.4. Enzyme inhibition assays
The library of triazoles shown in Figure 2 was assayed against
two glycosidases: sweet almond b-glucosidase (GH1) and yeast
a-glucosidase (GH13). In addition to the synthetic CuAAC-derived
products, 4-phenyl-triazole 32, benzhydrol 33 and two known low
micromolar b-glucosidase inhibitors, deoxynojirimycin (DNJ) 3451
and 4-phenylimidazole 35,52 were used as positive controls
(Fig. 6). Under the conditions of the enzyme assay the triazole
nitrogen (pKa 1.1–1.3)53 is not protonated, excluding any electro-
static interactions with charged amino acid residues within the ac-
tive site. Therefore the contribution of the triazole group per se to
glycosidase inhibition was expected to be limited.
ner N(11)–N(12) bond in b-isomer 19, whereas in
a-isomer 25
these bonds are more similar in value. This particular difference
between the azido group in 19 and 25 indicates a significant differ-
ence in electron distribution within this group for the two isomeric
compounds, which manifests itself as a difference in dipolar char-
acter and hence different reaction rates under CuAAC reaction con-
ditions. The higher reactivity of the b-azide 19 can be interpreted

S. Dedola et al. / Carbohydrate Research 345 (2010) 1123–1134
1127
Figure 4. ORTEP representation of the solid state structure of fully acetylated glucopyranosyl triazoles 24 (A) and 27 (B) viewed from the b-face of
D
-glucopyranose ring.
syl triazoles, which is perhaps surprising given the wide range of
hydrophobic compounds, including b-glycosides, that are known
to inhibit the almond enzyme.23,24,51,52
OAc
O
OH
AcO
AcO
OAc
O
N
N
N
OAc
AcO
AcO
2.4.2. b-Linked glucosyl triazoles and yeast a-glucosidase
The same set of b-linked triazoles 5a–11a, 12–18 and associ-
ated controls 32–35 were also assayed against their non-cognate
AcO
22
N
N
N
OAc
O
partner yeast
a-glucosidase (Fig. 7b). Once again, the DNJ 34 po-
N
N
N
AcO
AcO
O
sitive control demonstrated activity in the 10s of
lM range;
whilst benzhydrol 33 and 4-phenyl-imidazole 35 did not display
significant inhibition at 1 mM concentration, 4-phenyl-triazole
32 displayed some activity in the mM range. Of the library of
b-glucosyl triazoles assessed, only acid- and ester-substituted b-
OAc
O
24
27
Figure 5. Structure of glucopyranosyl triazoles 22,50 24 and 27 showing the relative
orientation of the sugar and triazole rings as determined by X-ray crystallography.
D
-glucopyranosides 9a and 11a, respectively, showed activity, giv-
ing rise to weak inhibition (60% and 40%) at 1 mM concentration.
Poor inhibition of an -glucosidase by non-cognate b-glucopyr-
a
OH
anosides is to be expected, given the stereochemical preference
N
N
of the enzyme.
NH
2.4.3.
glucosidase
Screening of
a-Linked glucosyl triazoles and sweet almond b-
32
33
a-glucopyranosyl triazoles 5b–11b (Fig. 2)
OH
against their non-cognate partner (based on stereospecificity)
sweet almond b-glucosidase revealed only one compound display-
ing any inhibitory activity—aminomethylene-triazole 10b—but
even then the activity was very weak compared to DNJ 34 and
4-phenyl-imidazole 35 (Fig. 8a). Given that sweet almond b-gluco-
sidase hydrolyses b-linkages, while the compounds screened are
N
H
N
HO
HO
NH
OH
34
35
Figure 6. Compounds 32 and 33 (positive controls), 34 and 35 screened against
glycosidases in parallel with synthetic glycosyl triazoles.
all a-configured, limited inhibition was to be expected.
2.4.4.
The set of
also assayed against a cognate binding partner, yeast
(Fig. 8b). In contrast to all the other inhibition data obtained, all the
a
-Linked glucosyl triazoles and yeast
-linked glucopyranosyl triazoles 5b–11b (Fig. 2) was
-glucosidase
a-glucosidase
2.4.1. b-Linked glucosyl triazoles and sweet almond b-
glucosidase
a
a
Screening of b-glucopyranosyl triazoles 5a–11a and 12–18
(Fig. 2) against their cognate partner (based on stereospecificity)
sweet almond b-glucosidase revealed that only triazoles 5a (ben-
zhydryloxymethylene), 6a (phenyl), 11a (carboxy) and 14 (phtha-
limido-methylene) possessed inhibitory activity, with the
remaining compounds exhibiting no measurable inhibition at
1 mM concentration (Fig. 7a). As expected, DNJ 34 and 4-phenyl-
a
a
-glucosyl triazoles 5b–11b showed an inhibitory activity towards
-glucosidase in the 100 M–1 mM range. Benzhydryloxymethyl-
l
ene derivative 5b proved to be significantly more active than benz-
hydrol 33 itself, as was the case for -glucosyl phenyltriazole 6b
a
compared to the parent 4-phenyl-triazole 32, indicating positive
contribution to binding from both the glycone and aglycone por-
tions of the inhibitor. The Boc-protected amine derivative 8b and
the methyl ester 9b were also reasonable inhibitors of the yeast en-
zyme, whilst their deprotected counterparts, amine 10b and car-
boxylic acid 11b, were somewhat less active.
imidazole 35 showed inhibitory activity in the 10s of
lM
range.51,52 Figure 7a shows enhancement of inhibition on b-glu-
cosylation of benzhydrol 33, giving triazole 5a. Overall, these data
show only very limited b-glucosidase inhibition by b-glucopyran-

1128
S. Dedola et al. / Carbohydrate Research 345 (2010) 1123–1134
Figure 7. Inhibition assay results for the library of b-linked glucopyranosyl triazoles 5a–11a, 12–18 and control compounds 32–35. Only positive responses are shown; the
error in the data is typically 5–10% or less. (a) Activity against sweet almond b-glucosidase [37 °C, pH 6.2 in AcONa 20 mM, PIPES 10 mM, EDTA 0.1 mM, DMSO 2%, NaN3
0.002%, monitoring the rate of release of p-nitrophenolate from p-nitrophenyl b-
D
-glucopyranoside (625
lM) over 30 min]. (b) Activity against yeast
a-glucosidase [37 °C, pH
6.8 in AcONa 20 mM, PIPES 10 mM, EDTA 0.1 mM, DMSO 2%, NaN3 0.002%, monitoring the rate of release of p-nitrophenol from p-nitrophenyl
a-
D
-glucopyranoside (200 M)
l
over 30 min].
Figure 8. Inhibition assay results for the library of
the data is typically 5–10% or less. (a) Activity against sweet almond b-glucosidase [37 °C, pH 6.2 in AcONa 20 mM, PIPES 10 mM, EDTA 0.1 mM, DMSO 2%, NaN3 0.002%,
monitoring the rate of release of p-nitrophenolate from p-nitrophenyl b- -glucopyranoside (625 M) over 30 min]. (b) Activity against yeast -glucosidase [37 °C, pH 6.8 in
-glucopyranoside (200 M) over
a-linked glucopyranosyl triazoles 5b–11b and control compounds 32–35. Only positive responses are shown; the error in
D
l
a
AcONa 20 mM, PIPES 10 mM, EDTA 0.1 mM, DMSO 2%, NaN3 0.002%, monitoring the rate of release of p-nitrophenol from p-nitrophenyl
a-
D
l
30 min].
2.5. Conclusions
came an issue, although incompatibility of propargyl amine and
propiolic acid with CuAAC conditions was overcome by application
of temporary protecting groups.
In the present study an expeditious synthesis of a library of var-
iously substituted
a- and b-linked glucopyranosyl triazoles 5a,b–
A significant difference in the reactivity of a- and b-D-glucopyr-
11a,b and 12–18 has been achieved in a parallel manner, using
the flexibility of the CuAAC ‘click chemistry’ approach. These syn-
theses gave rise to a number of observations. Firstly, for ease of
parallel synthesis, a catalytic couple of CuSO4/Cu proved practical
for microtitre plate-based triazole syntheses, while CuSO4/NaAsc
was effective for microwave-mediated reactions with either acety-
lated or unprotected sugar azides as starting materials. In explor-
ing a range of alkynes possessing diverse functional groups, the
tolerance of CuACC reaction towards various functionalities be-
anosyl azides towards alkynes in the CuAAC reaction was noted,
with the b-configured azide being at least threefold more reactive
than the
both the
a
-azide. Comparison of X-ray crystallographic data for
a- and b-linked glucopyranosyl azides highlighted the im-
pact of the anomeric effect on the dipolar character of the anomeric
azides, which likely accounts for the observed reactivity
differences.
The library of
a- and b-linked glucosyl triazoles was assessed
for glucosidase inhibitory activity. Given the remarkably relaxed

S. Dedola et al. / Carbohydrate Research 345 (2010) 1123–1134
1129
donor and aglycone site specificities of sweet almond b-glucosi-
A and purified by column chromatography on silica gel using an
appropriate gradient elution with hexane–EtOAc as a mobile
phase.
dase,51 the very weak inhibition observed in this study is perhaps
surprising. In contrast, the yeast
a-glucosidase showed a strong
preference for -linked glucosyl triazoles over their b-anomers,
a
regardless of the substitution on the triazole ring. However, at best
3.2.3. Method C (applied for synthesis of 12–18)
the inhibition observed was modest (50% inhibition in the 100s of
To a solution of azide 31 (30 mg, 0.146 mmol) in H2O (130
were added the alkyne (1.1 equiv), 1 M aq CuSO4Á5H2O (14.6
l
L)
lM range).
lL),
In summary, these studies have highlighted points relating to
a piece of copper turning (ꢀ5 mg) and 5:3:2 mixture of t-BuOH–
reactant compatibility and reactivity under CuAAC ‘click chemistry’
conditions, as well as providing rapid access to series of glucosyl
triazoles for biological evaluation.
H2O–EtOH (500 lL). The reaction was carried out in an HPLC vial
(2 mL) with stirring at 45 °C until reaction was complete (ꢀ24 h)
as judged by TLC (CH2Cl2–CH3OH 8:2). Solvents were removed un-
der reduced pressure to give a blue-green residue which was sus-
pended in CH3OH (3 mL) and filtered through a plug of silica gel
(1 cm in a Pasteur pipette), silica gel was washed with additional
CH3OH (3 mL) and the combined filtrates were concentrated under
reduced pressure to give a white amorphous solid. The product
was used in biological assays without further purification.
3. Experimental
3.1. General methods
Microwave-assisted syntheses were conducted in Biotage Initi-
ator system. Thin-layer chromatography (TLC) was performed on
aluminium-backed, pre-coated silica gel plates (Silica Gel 60
F254, Merck). Spots were detected by immersion in a 5% ethanolic
H2SO4, followed by heating to 200 °C. Column chromatography
was performed on a Biotage Horizon purification system using
pre-packed silica gel cartridges and gradient elution. Evaporation
of solvents was performed under reduced pressure at 25–40 °C.
Optical rotations were measured at 20 °C using a Perkin–Elmer
341 polarimeter. NMR spectra were recorded at 24 °C with a Varian
Unity Plus spectrometer at 400 MHz (1H) or 100.6 MHz (13C) or
with a Varian Gemini 2000 spectrometer at 75 MHz (13C). 1H
NMR and 13C NMR spectra were referenced to residual solvent
peaks. 1H NMR spectra were assigned with the help of gCOSY
experiments and 13C NMR spectra with the help of gHMBC and
gHSQC. Accurate electrospray ionisation mass spectra (ESI-MS)
were obtained using Thermofisher LTQ Orbitrap XL in positive
mode. Enzymatic assays were performed using a Dynex multiwell
3.3. General protecting group removal procedures
3.3.1. Deacetylation
To a solution of the acetylated compound in dry CH3OH a piece
of metallic sodium was added, the mixture was stirred at room
temperature until completion of the reaction (TLC), the solution
was neutralised with Dowex 50WX8-200 (H+) resin, the resin
was filtered off and the solvent was removed under reduced
pressure.
3.3.2. Removal of N-Boc protecting group
The N-Boc protected derivative was suspended in a mixture of
CH2Cl2–TFA 1:1 (5 mL) and stirred at room temperature until com-
pletion of the reaction (TLC). The mixture was concentrated with
toluene (20 mL) at reduced pressure and the operation was re-
peated several times until complete removal of TFA.
plate reader. 2,3,4,6-Tetra-O-acetyl-b-
D
-glucopyranosyl azide (19)
3.3.3. Deesterification of methyl esters
and 2,3,4,6-tetra-O-acetyl-
a
-D-glucopyranosyl azide (25) were pre-
pared according to the known procedure.31 Ring atom labelling of
triazole, triazole side chains and benzene used throughout this
work is exemplified in the structures below.
To a solution of methyl ester in H2O or 9:1 H2O–CH3OH mixture
1 M aq NaOH solution (10 equiv) was added and the mixture was
stirred at room temperature until reaction is complete (TLC). The
reaction mixture was neutralised with Dowex 50WX8-200 (H+) re-
sin, the resin was filtered off and solvents were removed under re-
duced pressure to give the free carboxylic acid.
γ
β
N
N
α
f
δ
R
N
Glc
g
e
3.4. Synthesis of acetylated glucopyranosides
3.2. General procedure for the Cu(I) catalysed 1,3-dipolar
cycloaddition
3.4.1. Prop-2-ynyloxydiphenylmethane
A 60% suspension of NaH mineral oil (200 mg 5.08 mmol) was
slowly added to a stirred soln of Ph2CHOH (696 mg, 3.76 mmol)
3.2.1. Method A (applied for synthesis of 21, 22 and 24)
A solution of the sugar azide (1 equiv), the alkyne (1.1 equiv),
1 M aq CuSO4Á5H2O (0.01 equiv) and 1 M aq sodium ascorbate
(0.1 equiv) in a t-BuOH–H2O 1:1 mixture (2.8 mL for 1 mmol of
the sugar azide) was heated at 70 °C at reflux until TLC showed
no traces of the starting sugar azide. The solvent was removed un-
der reduced pressure, the residue was dispersed in EtOAc (50 mL)
and the solution was washed with H2O (3 Â 15 mL), dried over
MgSO4 and concentrated to give a target adduct. In most cases,
materials prepared in this manner did not require further
purification.
and CH„CCH2Br (20 lL, 4.70 mmol) in DMF (20 mL) at 0 °C under
nitrogen. After stirring for 1 h at 22 °C the reaction was quenched
by slow addition of CH3OH at 0 °C with continuous stirring. The
solvents were removed under reduced pressure, the solid residue
was suspended in EtOAc (50 mL) and washed with H2O
(15 mL Â 2), the organic soln was dried over MgSO4, filtered and
concentrated. The title compound was obtained as a yellow oil,
yield 820 mg, (97%), Rf 0.67 (Hex–EtOAc 9:1) and used without fur-
ther purification in synthesis of 20 and 26.
3.4.2. 1-(2,3,4,6-Tetra-O-acetyl-b-D-glucopyranosyl)-4-
benzhydryloxymethyl-[1,2,3]-triazole (20)
3.2.2. Method B (applied for synthesis of 20, 23 and 26–30)
Prepared from azide 19 and prop-2-ynyloxydiphenylmethane
following Method B (10 min) as a colourless solid (238 mg 98%);
A solution of b-azide 19 or
a-azide 5 (1 equiv), the alkyne
(5 equiv), 1 M aq CuSO4Á5H2O (0.01 equiv) and 1 M sodium ascor-
bate (0.1 equiv) in DMF (0.35 mL for 1 mmol of the sugar azide)
was irradiated in a microwave reactor until the reaction was com-
plete (TLC). The target adduct was isolated as described in Method
[
a
]
À26.1 (c 1.0, CHCl3); dH (600 MHz, CDCl3): 7.79 (1H, s, H-e),
D
7.32 (10H, m, Ar), 5.88 (1H, d, J1,2 9.2 Hz, H-1), 5.49 (1H, s, CH-h),
5.46 (1H, t, J1,2 = J2,3 9.2 Hz, H-2), 5.42 (1H, t, J2,3 = J3,4 9.2 Hz,
H-3), 4.66 (2H, s, CH2-g), 4.30 (1H, dd, J5,6 4.8 Hz, J6a,6b 12.7 Hz,

1130
S. Dedola et al. / Carbohydrate Research 345 (2010) 1123–1134
H-6a), 4.16 (1H, d, J5,6b 4.0 Hz, J6a,6b 12.7 Hz, H-6b), 4.00 (1H, m, H-
5), 2.08, 2.07, 2.03, 1.85 (12H, s, CH3CO); dC (150 MHz, CDCl3):
170.8, 170.2, 169.7, 169.2 (CH3CO), 146.4 (C-f), 141.9 (C-Ar),
128.8 (C-Ar), 128.7 (C-Ar), 127.9 (C-Ar  2), 120.5 (C-e), 86.0 (C-
1), 83.1 (C-h), 75.4 (C-5), 73.0 (C-3), 70.6 (C-2), 68.0 (C-4), 62.4
(C-g), 61.7 (C-6), 21.0, 20.9, 20.8, 20.5 (CH3CO); HR ESI-MS found
m/z 618.2061 [M+Na]+; calcd for C30H33N3O10ÁNa 618.2058.
H-6b), 4.0 (1H, m, H-5), 3.95 (3H, s, CH3CO2-g), 2.07, 2.06, 2.02
(9H, s, CH3CO), 1.88 (3H, s, CH3CO); dC (100 MHz, CDCl3): 170.8,
170.2, 169.7, 169.3 (CH3CO), 160.9 (CH3OCO), 140.9 (C-f), 126.4
(C-e), 86.2 (C-1), 75.6 (C-5), 72.5 (C-3), 70.7 (C-2), 67.82 (C-4),
61.6 (C-6), 52.51 (triazole-CH3CO), 20.7, 20.6, 20.57, 20.2 (CH3CO);
HR ESI-MS found m/z 480.1228 [M+Na]+; calcd for C18H23N3O11Na
480.1225.
3.4.3. 1-(2,3,4,6-Tetra-O-acetyl-b-
D-glucopyranosyl)-4-phenyl-
3.4.7. 1-(2,3,4,6-Tetra-O-acetyl-a-D-glucopyranosyl)-4-
[1,2,3]-triazole (21)
benzhydryloxymethyl-[1,2,3]-triazole (26)
Prepared from azide 19 and ethynylbenzene following Method
A (45 min) as a colourless solid (248 mg, 97%); Rf 0.17 (Tol–EtOAc
Prepared from azide 25 (105 mg 0.281 mmol) and prop-2-yny-
loxydiphenylmethane (100
colourless solid (167 mg 99%); [a]
D
l
L) following Method B (30 min) as a
8:2); [
a
]
D À56.2 (c 1.0, CHCl3); dH (400 MHz, CDCl3): 8.00 (1H, s, H-
+78.9 (c 1.0, CH3Cl); dH
e), 7.84 (2H, d, Jb, 8.4 Hz, H-b), 7.42 (3H, m, H-
c
, H-d), 5.93 (1H, d,
(600 MHz, CDCl3): 7.65 (1H, s, H-e), 7.37 (4H, m, Ar), 7.34 (4H,
m, Ar), 7.26 (2H, m, Ar), 6.34 (1H, d, J1,2 6.0 Hz, H-1), 6.28 (1H, t,
J2,3 = J3,4 9.6 Hz, H-3), 5.54 (1H, s, CH-h), 5.31 (1H, dd, J1,2 6.0 Hz,
J2,3 9.6 Hz, H-2), 5.27 (1H, t, J3,4 = J4,5 9.6 Hz, H-4), 4.66 (2H, s,
CH2-g), 4.36 (1H, m, H-5), 4.25 (1H, dd, J5,6 = 2.7 Hz, J6a,6b = 12.6 Hz,
H-6a), 4.02 (1H, dd, J5,6 2.7 Hz, J6a,6b 12.6 Hz, H-6b), 2.06, 2.05, 2.03,
1.85 (12H, s, CH3CO); dC (150 MHz, CDCl3): 170.8, 170.5, 170.0,
169.9 (CH3CO), 145.5 (C-Ar), 141.8 (C-f), 128.8 (C-Ar), 128.7 (C-
Ar), 127.4 (C-Ar), 125.0 (C-e), 83.1 (C-h), 81.6 (C-1), 71.4 (C-5),
70.7 (C-3), 70.1 (C-2), 68.3 (C-4), 62.5 (C-g), 61.5 (C-6), 20.9, 20.8,
(CH3CO); HR ESI-MS found m/z 596.2237 [M+H]+; calcd for
C30H33N3O10ÁH 596.2239.
c
J1,2 9.2 Hz, H-1), 5.53 (1H, t, J1,2 = J2,3 9.2 Hz, H-2), 5.44 (1H, t,
J2,3 = J3,4 9.2 Hz, H-3), 5.25 (1H, t, J3,4 = J4,5 9.2 Hz, H-4), 4.33 (1H,
dd, J5,6 5.2 Hz, J6a,6b 12.6 Hz, H-6a), 4.15 (1H, d, J6a,6b 12.6 Hz, H-
6b), 4.04 (1H, m, H-5), 2.15, 2.10, 2.07 (9H, s, CH3CO), 1.88 (3H, s,
CH3CO); dC (100 MHz, CDCl3): 170.9, 170.4, 169.8, 169.4 (CH3CO),
148.9 (C-f), 130.3 (C-
a
) 129.3 (2 Â C- ), 128.9 (C-d), 126.3 (2 Â C-
c
b), 118.1 (C-e), 86.1 (C-1), 75.4 (C-5) 73.0 (C-3), 70.5 (C-2), 69.0
(C-4), 61.9 (C-6), 20.7 (Â3) and 20.4 (CH3CO); HR ESI-MS found
m/z 498.1484 [M+Na]+; calcd for C22H25N3O9Na 498.1483.
3.4.4. 1-(2,3,4,6-Tetra-O-acetyl-b-D-glucopyranosyl)-4-
hydroxymethyl-[1,2,3]-triazole (22)
Prepared from azide 19 and prop-2-yn-1-ol following Method A
(10 min) as a colourless solid (232 mg, 99%); Rf 0.26 (Tol–EtOAc
3.4.8. 1-(2,3,4,6-Tetra-O-acetyl-a-D-glucopyranosyl)-4-phenyl-
[1,2,3]-triazole (27)
1:9); [
a
]
À6.0 (c 1.0, CHCl3); dH (400 MHz, CDCl3): 7.82 (1H, s,
Azide 25 (168 mg, 0.451 mmol) and phenyl acetylene (247
0.451 mmol) were allowed to react following Method
(120 min) and the product was purified by re-crystallisation from
EtOAc–Hex to give 27 (134 mg, 63%); Rf 0.17 (Tol–EtOAc 8:2);
l
L,
B
D
H-e), 5.89 (1H, d, J1,2 9.1 Hz, H-1), 5.45 (1H, t, J1,2 = J2,3 9.1 Hz, H-
2), 5.43 (1H, t, J2,3 = J3,4 9.1 Hz, H-3), 5.24 (1H, t, J3,4 = J4,5 9.1 Hz,
H-4), 4.76 (2H, s, CH2-g), 4.26 (1H, dd, J5,6 4.8 Hz, J6a,6b 12.4 Hz,
H-6a), 4.12 (1H, d, J6a,6b 12.4 Hz, H-6b), 4.00 (1H, m, H-5), 3.15
(1H, s, CH2OH), 2.04 (6H, 2 Â s, CH3CO), 2.01 (3H, s, CH3CO), 1.84
(3H, s, CH3CO); dC (100 MHz, CDCl3): 171.0, 170.5, 169.9, 169.6,
(CH3CO), 149.0 (C-f), 120.7 (C-e), 81.1 (C-1), 75.5 (C-5), 73.1 (C-
3), 70.8 (C-2), 68.1 (C-4), 62.0 (C-6), 56.8 (CH2-g), 20.9, 20.8 (Â2)
and 20.6 (CH3CO); HR ESI-MS found m/z 452.1272 [M+Na]+; calcd
for C17H23N3O10ÁNaÁ452.1276.
mp 196–197 °C; [
a] +85.5 (c 1.0, CHCl3); dH (600 MHz, CDCl3):
D
7.86 (1H, s, H-e), 7.45 (2H, d, Jb, = 8.4 Hz, H-b), 7.42 (3H, m, H-
c
,
c
H-d), 6.42 (1H, d, J1,2 6.0 Hz, H-1), 6.35 (1H, t, J2,3 = J3,4 9.6 Hz, H-
3) 5.34 (1H, dd, J1,2 6.0, Hz, J2,3 9.6 Hz, H-2), 5.81 (1H, t, J3,4 = J4,5
9.6 Hz, H-4), 4.39 (1H, m, H-5), 4.27 (1H, dd, J5,6 4.2 Hz, J6a,6b
12.6 Hz, H-6a), 4.04 (1H, d, J6a,6b 12.6 Hz, H-6b), 2.07, 2.06, 2.04,
(9H, s, CH3CO), 1.88 (3H, s, CH3CO); dC (150 MHz, CDCl3): 170.6,
170.5, 169.9, 169.8 (CH3CO), 147.5 (C-e), 130.3 (C-
a
) 129.3 (Â2)
3.4.5. 1-(2,3,4,6-Tetra-O-acetyl-b-
butoxycarbonyl-aminomethyl)-[1,2,3]-triazole (23)
Prepared from azide 19 and tert-butyl prop-2-ynylcarbamate
following Method B (2 h) as a colourless solid (85 mg, 95%); Rf
0.40 (Hex–EtOAc 4:6); [
CDCl3): 7.74 (1H, s, H-e), 5.85 (1H, d, J1,2 8.2 Hz, H-1), 5.21 (2H,
m, H-2, H-3), 5.22 (1H, t, J3,4 = J4,5 8.2 Hz, H-4), 5.10 (1H, s, NH),
4.40 (1H, d, J 4.8 Hz, CH2-g), 4.3 (1H, dd, J5,6 4.9 Hz, J6a,6b 12.7 Hz,
H-6a), 4.11 (1H, d, 4.0 J6a,6b 12.7 Hz, H-6b), 3.98 (1H, m, H-5),
2.07, 2.05, 2.26 (9H, s, CH3CO), 1.86 (3H, s, CH3CO), 1.43 [9H, s,
(CH3)3CNH]; dC (100 MHz, CDCl3): 170.8, 170.2, 169.6, 169.0
(CH3CO), 156.3 [C(CH3)3], 155.9 (NHCO), 146.4 (C-f), 120.5 (C-e),
86.0 (C-1), 75.4 (C-5), 72.9 (C-3), 70.5 (C-2), 67.9 (C-4), 61.7 (C-
6), 36.4 (CH2-g), 29.9 [C(CH3)3]; 20.9, 20.8, 20.8, 20.4 (CH3CO); HR
ESI-MS found m/z 551.1962 [M+Na]+; calcd for C22H32N4O11Na
551.1960.
D-glucopyranosyl)-4-(tert-
(C-
c
), 128.9 (C-d), 126.3 (Â2 C-b), 118.1 (C-f), 86.1 (C-1), 75.4 (C-
5) 73.0 (C-3), 70.5 (C-2), 69.0 (C-4), 61.9 (C-6), 20.7 (Â3), 20.4
(CH3CO); HR ESI-MS found m/z 476.1662 [M+H]+; calcd for
C22H25N3O9ÁH 476.1664.
a]
À20.4 (c 0.5, CHCl3); dH (400 MHz,
D
3.4.9. 1-(2,3,4,6-Tetra-O-acetyl-a-D-glucopyranosyl)-4-
hydroxymethyl-[1,2,3]-triazole (28)
Prepared from azide 25 (205 mg, 0.549 mmol) and prop-2-yn-
1-ol (0.160
lL, 2.745 mmol) following Method B (60 min) to give
a colourless solid (165 mg, 70%); Rf 0.26 (Tol–EtOAc 1:9); [
a
]
D
+99.4 (c 1.0, CHCl3); dH (600 MHz, CDCl3): 7.66 (1H, s, H-e), 6.36
(1H, d, J1,2 6.0 Hz, H-1), 6.25 (1H, t, J2,3 = J3,4 9.6 Hz, H-3), 5.32
(1H, dd, J1,2 6.0, J2,3 9.6 Hz, H-2), 5.25 (1H t, J3,4 = J4,5 9.6 Hz, H-4),
4.83 (2H, s, CH2-g), 4.32 (1H, m, H-5), 4.30 (1H, dd, J5,6 4.2 Hz,
J6a,6b 12.6 Hz, H-6a), 4.00 (1H, dd, J5,6 4.2 Hz, J6a,6b 12.6 Hz, H-6b),
2.81 (1H, s, CH2OH), 2.06, 2.05, 2.02 (9H, CH3CO), 1.87 (3H, s,
CH3CO); dC (150 MHz, CDCl3): 170.6, 170.3, 169.8, 169.7, (CH3CO),
147.4 (C-f), 124.1 (C-e), 81.5 (C-1), 71.2 (C-5), 70.5 (C-3), 69.89
(C-2), 68.1 (C-4), 61.4 (C-6), 56.4 (CH2-g), 20.8 (Â2), 20.7, 20.5
(CH3CO); HR ESI-MS found m/z 430.1446 [M+H]+; calcd for
C17H23N3O10ÁH 430.1456.
3.4.6. 1-(2,3,4,6-Tetra-O-acetyl-b-D-glucopyranosyl)-4-
methoxycarbonyl-[1,2,3]-triazole (24)
Prepared from azide 19 and methyl propiolate were reacted fol-
lowing Method A (45 min) as a colourless solid (88 mg 70%); Rf
0.20 (PET–EtOAc 5:5); mp 205–207.5 (DMF); [
CHCl3); dH (400 MHz, CDCl3): 8.36 (1H, s, H-e), 5.92 (1H, d, J1,2
9.1 Hz, H-1), 5.43 (1H, t, J2,3 = J3,4 9.1 Hz, H-3), 5.39 (1H, t,
J1,2 = J2,3 9.1 Hz, H-2), 5.24 (1H, t, J3,4 = J4,5 9.1 Hz, H-4), 4.31 (1H,
dd, J5,6 5.2 Hz, J6a,6b 12.6 Hz, H-6a), 4.16 (1H, d, J6a,6b 12.6 Hz,
a]
À28.5 (c 1.0,
D
3.4.10. 1-(2,3,4,6-Tetra-O-acetyl-a-D-glucopyranosyl)-4-(tert-
butyl-oxycarbonylaminomethyl)-[1,2,3]-triazole (29)
Prepared from azide 25 (157 mg, 0.421 mmol) and tert-butyl
prop-2-ynylcarbamate (176 mg, 1.052 mmol) following Method B

S. Dedola et al. / Carbohydrate Research 345 (2010) 1123–1134
1131
to give a colourless solid (209 mg, 94%); Rf 0.47 (Hex–EtOAc 4:6);
+3.6 (c 0.5, CHCl3); dH (600 MHz, CDCl3): 7.59 (1H, s, H-e),
d, J1,2 9.1 Hz, H-1), 4.76 (2H, s, CH2-g), 4.01 (1H, t, J1,2 = J2,3 9.1 Hz,
H-2), 3.91 (1H, br d, J6a,6b 10.9 Hz, H-6a), 3.75 (3H, m, H-3, H-5, H-
6b), 3.63 (1H, t, J3,4 = J4,5 9.1 Hz, H-4); dC (100 MHz, D2O): 148.0 (C-
f), 124.1 (C-e), 88.1 (C-1), 79.6 (C-5), 76.7 (C-3), 73.0 (C-2), 69.7 (C-
4), 61.1 (C-6), 55.3 (C-g); HR ESI-MS found m/z 284.0852 [M+Na]+;
calcd for C9H15N3O6ÁNa 284.08653.
[a]
D
6.30 (1H, d, J1,2 = 6.0 Hz, H-1), 6.25 (1H, t, J2,3 = J3,4 9.6 Hz, H-3),
5.30 (1H, dd, J1,2 6.0, J2,3 9.6 Hz, H-2), 5.26 (1H, t, J3,4 = J4,3 9.6 Hz,
H-4), 5.12 (1H, s, NH), 4.42 (1H, br d, CH2-g), 4.35 (1H, m, H-5),
4.25 (1H, dd, J5,6 4.22 Hz, J6a,6b 12.6 Hz, H-6a), 4.00 (1H, d, J5,6
4.22 Hz, J6a,6b 12.7 Hz, H-6b), 2.07, 2.06, 2.03 (9H, s, CH3CO), 1.87
(3H, s, CH3CO), 1.44 [9H, s, (CH3)3C]; dC (150 MHz, CDCl3): 158.3
(NHCO), 147.2 (C-f), 123.2 (C-e), 89.6 (C-1), 81.1 (C-5), 80.4
[C(CH3)3], 78.4 (C-3), 74.0 (C-2), 70.9 (C-4), 62.4 (C-6), 36.7 (CH2-
g), 28.7 [C(CH3)3]; HR ESI-MS found m/z 529.2139 [M+H]+; calcd
for C22H32N4O11ÁH 529.1956.
3.5.4. 1-(b-D-Glucopyranosyl)-4-(tert-butyl-
oxycarbonylaminomethyl)-[1,2,3]-triazole (8a)
Compound 23 (83 mg, 0.158 mmol) was deacetylated to give a
white solid (53.5 mg, 91%); Rf 0.80 (CH2Cl2–MeOH–H2O 7:2:1);
[a] +1.0 (c 0.5, CD3OD); dH (400 MHz, CD3OD) 8.02 (1H, s, H-e),
D
5.57 (1H, d, J1,2 9.2 Hz, H-1), 4.32 (2H, s, CH2-g), 3.87 (2H, m, H-
2, H-6a), 3.71 (1H, dd, J5,6 3.0 Hz, J6a,6b 8.0 Hz, H-6b), 3.55 (2H, m,
H-3, H-5), 3.49 (1H, t, J3,4 = J4,5 9.2 Hz, H-4), 1.44 [9H, s, (CH3)3];
dC (100 MHz, CD3OD): 158.3 (NHCO), 147.2 (C-f), 123.2 (C-e),
89.6 (C-1), 81.1 (C-5), 80.4 [C(CH3)3], 78.4 (C-3), 74.0 (C-2), 70.9
(C-4), 62.4 (C-6), 36.7 (CH2-g), 28.7 [C(CH3)3]; HR ESI-MS found
m/z 383.1539 [M+Na]+; calcd for C14H24N4O7ÁNa 383.1537.
3.4.11. 1-(2,3,4,6-Tetra-O-acetyl-a-D-glucopyranosyl)-4-
methyloxycarbonyl-[1,2,3]-triazole (30)
Prepared from azide 25 (168 mg, 0.451 mmol) and methyl pro-
piolate (200
purified by crystallisation from EtOAc–Hex to give a white powder
(198 mg 96%); Rf 0.17 (Hex–EtOAc 5:5); [ D +100.1 (c 1.0, CHCl3);
lL, 2.255 mmol) following Method B (45 min) and
a]
dH (600 MHz, CDCl3): 8.22 (1H, s, H-e), 6.41 (1H, d, J1,2 6.0 Hz, H-1),
6.17 (1H, t, J2,3 = J3,4 9.6 Hz, H-3), 5.33 (1H, dd, J1,2 6.0 Hz, J2,3 9.6 Hz,
H-2), 5.24 (1H, t, J3,4 = J4,5 9.6 Hz, H-4), 4.35 (1H, m, H-5), 4.25 (1H,
dd, J5,6 4.2 Hz, J6a,6b 12.6 Hz, H-6a), 4.02 (1H, dd, J5,6 4.2 Hz, J6a,6b
12.6 Hz, H-6b), 3.95 (3H, s, CH3OCO), 2.05, 2.04, 2.01 (9H, s, CH3CO),
1.86 (3H, s, CH3COC-2); dC (150 MHz, CDCl3): 170.5, 170.1, 169.7,
169.6 (CH3CO), 160.7 (triazole-CH3OCO), 139.7 (C-f), 129.8 (C-e),
82.1 (C-1), 71.7 (C-5), 70.2 (C-3), 69.6 (C-2), 67.9 (C-4), 61.3 (C-
6), 52.5 (CH3CO), 20.7, 20.6, 20.5, 20.4 (CH3CO); HR ESI-MS found
m/z 480.1225 [M+Na]+; calcd for C18H23N3O11ÁNa 480.1225.
3.5.5. 1-(b-D-Glucopyranosyl)-4-methoxycarbonyl-[1,2,3]-
triazole (9a)
Compound 24 (97 mg, 0.213 mmol) was deacetylated to give a
white solid (58 mg, 95%); Rf 0.60 (CH2Cl2–MeOH–H2O 6:3:1);
[a] +0.5 (c 0.5, CH3OH); dH (400 MHz, CD3OD): 8.81 (1H, s, H-e),
D
5.68 (1H, d, J1,2 9.2 Hz, H-1), 3.89 (5H, m, H-2, H-6a, CH3OCO-g),
3.72 (1H, dd, J5,6 5.8 Hz, J6a,6b 12.4 Hz, H-6b), 3.58 (2H, m, H-3, H-
5), 3.52 (1H, t, J3,4 = J4,5 9.2 Hz, H-4); dC (100 MHz, CD3OD): 141.9
(C-f), 124.6 (C-e), 89.5 (C-1), 81.1 (C-5), 78.5 (C-3), 74.0 (C-2),
70.9 (C-4), 62.3 (C-6), 35.6 (CH2-g); HR ESI-MS found m/z
290.0982 [M+H]+; calcd for C10H16N3O7ÁH 290.0983.
3.5. Unprotected glucopyranosides
3.5.1. 1-(b-
D-Glucopyranosyl)-4-methyl-benzhydryloxymethyl-
3.5.6. 1-(b-D-Glucopyranosyl)-4-aminomethyl-[1,2,3]-triazole
[1,2,3]-triazole (5a)
(10a)
Compound 20 (25 mg, 40.5
l
mol) was deacetylated to give a
Compound 8a (28 mg, 0.079 mmol) was treated as described in
Section 3.3.2 to give 10a as a yellow solid (27 mg, 91%); [
À0.5
white solid (16 mg, 88%);
[
a
]
À26.1 (c 1.0, CH3OH); dH
a]
D
D
(600 MHz, CD3OD): 8.19 (1H, s, H-e), 7.37 (3H, m, Ar), 7.31 (3H,
m, Ar), 7.24 (2H, m, Ar), 5.61 (1H, d, J1,2 9.1 Hz, H-1), 5.55 (1H, s,
CH-h), 4.06 (2H, s, CH2-g), 3.90 (1H, t, J1,2 = J2,3 9.1 Hz, H-2), 3.88
(1H, dd, J5,6 5.4 Hz, J6a,6b 10.9 Hz, H-6a), 3.72 (1H, dd, J5,6 5.4 Hz
J6a,6b 10.9 Hz, H-6b), 3.57 (2H, m, H-3, H-5), 3.51 (1H, t, J3,4 = J4,5
9.1 Hz, H-4); dC (150 MHz, CD3OD): 146.1 (C-f), 143.2 (C-Ar),
130.9 (C-Ar), 129.4 (C-Ar), 128.6 (C-Ar), 128.1 (C-Ar), 124.4 (C-e),
89.6 (C-1), 84.2 (C-h), 81.0 (C-3 or C-5), 78.4 (C-3 or C-5), 73.9
(C-2), 70.8 (C-4), 62.7 (C-6), 62.3 (C-g); HR ESI-MS found m/z
428.1816 [M+Na]+; calcd for C25H25N3O6ÁH 428.1816.
(c 0.5, CH3OH); dH (400 MHz, CD3OD): 8.25 (1H, s, H-e), 5.64 (1H, d,
J1,2 6.2 Hz, H-1), 4.24 (2H, s, CH2-g), 3.89 (2H, m, H-2, H-6a), 3.71
(1H, dd, J5,6 3.6 Hz, J6a,6b 8.0 Hz, H-6b), 3.55 (2H, m, H-3, H-5),
3.49 (1H, t, J3,4 = J4,5 6.2 Hz, H-4); dC (100 MHz, CD3OD): 141.9 (C-
f), 124.6 (C-e), 89.5 (C-1), 81.1 (C-5), 78.5 (C-3), 74.0 (C-2), 70.9
(C-4), 62.3 (C-6), 35.6 (CH2-g); HR ESI-MS found m/z 261.1189
[M+H]+; calcd for C14H24N4O7?H 261.1193.
3.5.7. 1-(b-D-Glucopyranosyl)-4-carboxy-[1,2,3]-triazole (11a)
Compound 9a (159 mg, 0.552 mmol) was deprotected accord-
ing method Section 3.3.3 to give a white solid (139 mg, 92%); dH
(400 MHz, CD3OD): 8.48 (1H, s, H-e), 5.66 (1H, d, J1,2 9.2 Hz, H-1),
3.89 (1H, t, J1,2 = J2,3 9.2 Hz, H-2), 3.78 (1H, br d, J6a,6b 12.0 Hz H-
6a), 3.62 (3H, m, H-3, H-5, H-6b) 3.50 (1H, t, J3,4 = J4,5 9.2 Hz, H-
4); dC (100 MHz, CD3OD): 164.9 (CO), 142.2 (C-f), 127.5 (C-e),
87.4 (C-1), 78.7 (C-5), 75.6 (C-3), 72.1 (C-2), 68.7 (C-4), 60.2 (C-
6); HR ESI-MS found m/z 290.0982 [M+H]+; calcd for for
C10H16N3O7ÁH 290.0983.
3.5.2. 1-(b-
Compound 21 (110 mg, 0.235 mmol) was deacetylated to give a
white solid (67 mg, 94%); Rf 0.78 (CH2Cl2–MeOH–H2O 6:3:1); [
À7.6 (c 0.6, CH3OH); dH (400 MHz, CD3OD): 8.55 (1H, s, H-e), 7.84
(2H, d, Jb, 4.8 Hz, H-b), 7.44 (2H, t, Jb, = J ,d 4.8 Hz, H- ), 7.35 (1H, t,
4.8 Hz, H-d), 5.66 (1H, d, J1,2 9.2 Hz, H-1), 3.95 (1H, t, J1,2 = J2,3
D-Glucopyranosyl)-4-phenyl-[1,2,3]-triazole (6a)
a]
D
c
c
c
c
J
c,d
9.2 Hz, H-2) 3.90 (1H, br d, J5,6 3.6 Hz, H-6a) 3.74 (1H, dd, J5,6
3.6 Hz, J6a,6b 8.0 Hz, H-6b), 3.61 (2H, m, H-3, H-5), 3.54 (1H, t,
J3,4 = J4,5 9.2 Hz, H-4); dC (100 MHz, CD3OD): 148.9 (C-f), 131.5 (C-
3.5.8. 1-(a-D-Glucopyranosyl)-4-methyl-benzhydryloxymethyl-
a
), 130.0 (C-
c
 2), 129.5 (C-d), 126.7 (C-b  2), 121.4 (C-e), 89.7
[1,2,3]-triazole (5b)
Compound 26 (70 mg, 0.118 mmol) was deacetylated to give 5b
as a white solid (45 mg, 90%); Rf 0.38 (CH2Cl2–CH3OH); [a] +50.1
(c 1.0, CH3OH); dH (600 MHz, CD3OD): 8.12 (1H, s, H-e), 7.39 (4H,
m, Ar), 7.31 (4H, m, Ar), 7.24 (2H, m, Ar), 6.20 (1H, d, J1,2 6.0 Hz,
H-1), 5.57 (1H, s, CH2-h), 4.64 (2H, s, CH2-g), 4.38 (1H, t, J2,3 = J3,4
9.3 Hz, H-3), 3.98 (1H, dd, J1,2 6.0 Hz, J2,3 9.3 Hz, H-2), 3.81 (1H,
m, H-5), 3.78 (1H, dd, J5,6 3.9 Hz, J6a,6b 12.0 Hz, H-6a), 3.69 (1H,
dd, J5,6 3.9 Hz J6a,6b 12.0 Hz, H-6b), 3.51 (1H, t, J3,4 = J4,5 9.3 Hz,
H-4); dC (150 MHz, CD3OD): 145.2 (C-Ar), 143.3 (C-f), 128.6
(C-1), 81.1 (C-5), 78.4 (C-3), 74.1 (C-2), 70.9 (C-4), 62.4 (C-6); HR
ESI-MS found m/z 308.1242 [M+H]+; calcd for C14H17N3O5ÁH
308.1241.
D
3.5.3. 1-(b-D-Glucopyranosyl)-4-hydroxymethyl-[1,2,3]-triazole
(7a)
Compound 22 (123 mg, 0.287 mmol) was deacetylated to give a
white solid (70 mg, 92%); Rf 0.38 (CH2Cl2–MeOH–H2O 6:3:1); [
+85.5 (c 1.0, CHCl3); dH (400 MHz, D2O) 8.21 (1H, s, H-e), 5.76 (1H,
a]
D

1132
S. Dedola et al. / Carbohydrate Research 345 (2010) 1123–1134
(C-Ar), 128.1 (C-Ar), 128.6 (C-Ar), 128.1 (C-Ar), 127.4 (C-e), 87.2 (C-
1), 84.2 (C-h), 77.5 (C-5), 74.8 (C-3), 72.4 (C-2), 71.4 (C-4), 62.7 (C-
g), 62.4 (C-6); HR ESI-MS found m/z 428.1818 [M+H]+; calcd for
C25H25N3O6ÁH 428.1816.
H-4); dC (150 MHz, CD3OD): 140.3 (C-f), 127.8 (C-e), 87.2 (C-1),
77.6 (C-5), 74.7 (C-3), 72,2 (C-2), 71.3 (C-4), 62.3 (C-6), 35.3 (C-
g); HR ESI-MS found m/z 261.1189 [M+H]+; calcd for C14H24N4O7ÁH
261.1193.
3.5.9. 1-(
a-
D-Glucopyranosyl)-4-phenyl-[1,2,3]-triazole (6b)
3.5.14. 1-(a-D-Glucopyranosyl)-4-carboxy-[1,2,3]-triazole (11b)
Compound 27 (65 mg, 0.137 mmol) was deacetylated to give 6b
as a white solid (49 mg, 99%); Rf 0.55 (CH2Cl2–MeOH–H2O 8:2); dH
Compound 9b (37 mg, 0.128 mmol) was deprotected following
the general method Section 3.3.3 to give 11b as a white solid
(33 mg, 94%); dH (600 MHz, CD3OD): 8.05 (1H, s, H-e), 6.24 (1H,
d, J1,2 6.0 Hz, H-1), 4.35 (1H, t, J2,3 = J3,4 9.3 Hz, H-3), 3.99 (1H, dd,
J1,2 6.0 Hz, J2,3 9.3 Hz, H-2), 3.85 (1H, m, H-5), 3.77 (1H, dd, J5,6
3.6 Hz, J6a,6b 12.0 Hz, H-6a), 3.70 (1H, dd, J5,6 3.6 Hz, J6a,6b 12.0 Hz,
H-6b), 3.50 (1H, t, J3,4 = J4,5 9.3 Hz, H-4); dC (150 MHz, CD3OD):
142.8 (C-f), 131.0 (C-e), 87.5 (C-1), 77.8 (C-5), 74.7 (C-3), 72.3 (C-
2), 71.3 (C-4), 62.3 (C-6); HR ESI-MS found m/z 261.1189 [M+H]+;
calcd for C14H24N4O7ÁH 261.1193.
(600 MHz, CD3OD): 8.44 (1H, s, H-e), 7.84 (2H, d, Jb, = 7.5 Hz, H-b),
c
7.42 (2H, t, Jb, = J 7.5 Hz, H-c), 7.35 (1H, t, J 7.5 Hz, H-d), 6.23
c
c
,d
c,d
(1H, d, J1,2 5.4 Hz, H-1), 4.21 (1H, t, J2,3 = J3,4 9.3 Hz, H-3), 4.00 (1H,
dd, J1,2 5.4 Hz, J2,3 9.3 Hz, H-2), 3.84 (1H, m, H-5), 3.79 (1H, dd, J5,6
4.2 Hz, J6a,6b 12.3, H-6a), 3.69 (1H, dd, J5,6 5.4 Hz, J6a,6b 12.3 Hz, H-
6b), 3.52 (1H, t, J3,4 = J4,5 9.3 Hz, H-4); dC (150 MHz, CD3OD):
148.4 (C-f), 132.0 (C-
a
), 130.5 (C-
c
 2), 129.9 (C-d), 127.3 (C-
b  2), 125.0 (C-e), 87.8 (C-1), 78.1 (C-5), 75.4 (C-3), 72.9 (C-2),
71.9 (C-4), 62.9 (C-6); HR ESI-MS found m/z 308.1240 [M+H]+;
calcd for C14H17N3O5ÁH 308.12410.
3.5.15. 1-(b-D-Glucopyranosyl)-4-benzyl-[1,2,3]-triazole (12)
Prepared from azide 31 and prop-2-ynylbenzene according to
Method C as a white solid, (15 mg, 33%); dH (600 MHz, CD3OD):
3.5.10. 1-(
a-D-Glucopyranosyl)-4-hydroxymethyl-[1,2,3]-
triazole (7b)
7.90 (1H, s, H-e), 7.28 (4H, m, H-b, H-c), 7.20 (1H, t, J ,d = 6.6 Hz,
c
Compound 28 (50 mg, 0.137 mmol) was deacetylated to give 7b
as a white solid (28 mg, 94%); dH (600 MHz, CD3OD): 8.04 (1H, s, H-
e), 6.17 (1H, d, J1,2 6.0 Hz, H-1), 4.70 (2H, s, CH2-g), 4.35 (1H, t,
J2,3 = J3,4 9.6 Hz, Hz, H-3), 3.97 (1H, dd, J1,2 6.0 Hz, J2,3 9.6 Hz, H-
2), 3.75 (2H, m, H-5, H-6a), 3.68 (1H, dd, J5,6 5.4 Hz, J6a,6b 12.3 Hz,
H-6b), 3.49 (1H, t, J3,4 = J4,5 9.6 Hz, H-4); dC (150 MHz, CD3OD):
148.7 (C-f), 126.9 (C-e), 87.6 (C-1), 77.9 (C-5), 75.4 (C-3), 72.9 (C-
2), 71.9 (C-4), 62.8 (C-6), 56.9 (CH2-g); HR ESI-MS found m/z
284.0852 [M+Na]+; calcd for C9H15N3O6ÁNa 284.08653.
H-d), 5.56 (1H, d, J1,2 9.6 Hz, H-1), 4.06 (2H, s, CH2-g) 3.87 (2H,
m, H-2, H-6a) 3.69 (1H, dd, J5,6 5.6 Hz, J6a,6b 12.3 Hz, H-6b) 3.54
(2H, m, H-3, H-5), 3.47 (1H, t, J3,4 = J4,5 9.6 Hz, H-4); dC (150 MHz,
CD3OD): 140.2 (C-f), 129.6 (C-
a
, C-
c
 2, C-b  2), 129.5 (C-d),
127.5 (C-e), 89.6 (C-1), 81.1 (C3 or C-5), 78.5 (C-3 or C5), 73.9 (C-
2), 70.9 (C-4), 62.4 (C-6), 32.6 (CH2-g); HR ESI-MS found m/z
322.1399 [M+H]+; calcd for C15H19N3O5ÁH 322.1397.
3.5.16. 1-(b-D-Glucopyranosyl)-4-phthalimidomethyl-[1,2,3]-
triazole (13)
3.5.11. 1-(
a
-
D
-Glucopyranosyl)-4-(tert-butyl-
Prepared from azide 31 and 3-phthalimidoprop-1-yne accord-
ing to Method C as a white solid (57 mg, 80%); dH (600 MHz,
CD3OD): 8.19 (1H, s, H-e), 7.89, (2H, m, CH-Ar), 7.83 (2H, m, CH-
Ar), 5.58 (1H, d, J1,2 9.6 Hz, H-1), 4.98 (2H, s, CH2-g), 3.89 (2H, m,
H-2, H-6a), 3.70 (1H, dd, J5,6 5.4 Hz, J6a,6b 12.0 Hz, H-6b), 3.57 (2H,
m, H-3, H-5), 3.49 (1H, t, J3,4 = J4,5 9.6 Hz, H-4); dC (150 MHz,
CD3OD): 144.5 (C-f), 169.05 (CO  2), 135.5 (C-Ar  2), 133.4 (C-
Ar  2), 124.4 (C-Ar  2), 124.1 (C-e), 89.6 (C-1), 81.1 (C-3 or C5),
78.4 (C-3 or C5), 74.0 (C-2), 70.9 (C-4), 62.4 (C-6), 33.7 (CH2-g);
HR ESI-MS found m/z 391.1250 [M+H]+; calcd for C17H18N4O7ÁH
391.1248
oxycarbonylaminomethyl)-[1,2,3]-triazole (8b)
Compound 29 (141 mg, 0.266 mmol) was deacetylated to give
8b as a white solid (92 mg, 99%); Rf 0.46 (CH2Cl2–MeOH 8:2); dC
(600 MHz, CD3OD): 7.96 (1H, s, H-e), 6.16 (1H, d, J1,2 6.0 Hz, H-1),
4.34 (1H, t, J2,3 = J3,4 9.3 Hz, H-3), 4.00 (1H, dd, J1,2 6.0 Hz, J2,3
9.3 Hz, H-2), 3.75 (2H, m, H-5, H-6a), 3.66 (1H, dd, J5,6 5.4 Hz,
J6a,6b 12.3 Hz, H-6b), 3.52 (1H, t, J3,4 = J4,5 9.3 Hz, H-4), 1.44 [9H, s,
(CH3)3C]; dC (150 MHz, CD3OD): 158.3 (NHCO), 146.7 (C-f), 126.8
(C-e), 87.6 (C-1), 80.9 [C(CH3)3], 77.9 (C-5), 75.4 (C-3), 72.9 (C-2),
71.9 (C-4), 62.8 (C-6), 36.8 (CH2-g), 28.9 [C(CH3)3]; HR ESI-MS
found m/z 361.17178 [M+H]+; calcd for C14H24N4O6ÁH 361.17178.
3.5.17. 1-(b-D-Glucopyranosyl)-4-(2-hydroxypropyl)-[1,2,3]-
3.5.12. 1-(
(9b)
a-D-Glucopyranosyl)-4-carboxymethyl-[1,2,3]-triazole
triazole (14)
Prepared from azide 31 and pent-4-yn-2-ol according to Meth-
od C as a white solid (12 mg, 28%) dH (600 MHz, CD3OD): 7.99 (1H,
s, H-e), 5.57 (1H, d, J1,2 9.6 Hz, H-1), 4.06 (1H, br s, CH-h), 3.89 (2H,
m, H-2, H-6a), 3.70 (1H, dd, J5,6 5.4 Hz, J6a,6b 12.0 Hz, H-6b), 3.57
(2H, m, H-3, H-5), 2.40 (2H, m, CH2-g), 3.49 (1H, t, J3,4 = J4,5
9.6 Hz, H-4) 1.21 (3H, m, CH3-i); dC (150 MHz, CD3OD): 141.9 (C-
f), 123.8 (C-e), 89.5 (C-1), 81.1 (C-3 or C5), 78.5 (C-3 or C5), 74.1
(C-2), 70.9 (C-4), 68.0 (C-h), 62.3 (C-6), 35.9 (C-g). 23.1 (CH3-i);
HR ESI-MS found m/z 290.1345 [M+H]+; calcd for C11H19N3O6ÁH
290.1347.
Compound 30 (158 mg, 0.346 mmol) was deacetylated to give
9b as a white solid (113 mg, 99%); Rf 0.41 (CH2Cl2–MeOH–H2O
8:2); dH (600 MHz, CD3OD): 8.68 (1H, s, H-e), 6.25 (1H, d, J1,2
6.0 Hz, H-1), 4.30 (1H, t, J2,3 = J3,4 9.6 Hz, H-3), 3.98 (1H, dd, J1,2
6.0 Hz, J2,3 9.6 Hz, H-2), 3.98 (3H, s, CH3OCO), 3.87 (1H, m, H-5),
3.78 (1H, dd, J5,6 5.4 Hz, J6a,6b 12.3 Hz, H-6a), 3.69 (1H, dd, J5,6
5.4 Hz, J6a,6b 12.3 Hz, H-6b), 3.50 (1H, t, J3,4 = J4,5 9.6 Hz, H-4); dC
(150 MHz, CD3OD): 162.9 (CH3OCO), 140.1 (C-f), 132.5 (C-e), 88.2
(C-1), 78.5 (C-5), 75.1 (C-3), 72.6 (C-2), 71.7 (C-4), 62.8 (C-6),
53.1 (CH3OCO); HR ESI-MS found m/z 312.0801 [M+Na]+; calcd
for C10H15N3O7ÁNa 312.0802.
3.5.18. 1-(b-D-Glucopyranosyl)-4-(1-hydroxypropyl)-[1,2,3]-
triazole (15)
3.5.13. 1-(b-
(10b)
D
-Glucopyranosyl)-4-aminomethyl-[1,2,3]-triazole
Prepared from azide 31 and pent-1-yn-3-ol according to Meth-
od C as a white solid (24 mg, 82%); dH (600 MHz, CD3OD): 8.76 (1H,
s, H-e), 5.60 (1H, d, J1,2 9.4 Hz, H-1), 4.74 (1H, br s, CH-g), 3.89 (2H,
m, H-2, H-6a), 3.70 (1H, dd, J5,6 4.8 Hz, J6a,6b 12.3 Hz, H-6b), 3.57
(2H, m, H-3, H-5), 3.49 (1H, t, J3,4 = J4,5 9.4 Hz, H-4), 1.86 (2H, m,
CH2-h), 0.97 (3H, m, CH3-i), dC (150 MHz, CD3OD): 153.0 (C-f),
122.5 (C-e), 89.6 (C-1), 81.1 (C-3 or C5), 78.5 (C-3 or C5), 74.0
(C-2), 70.9 (C-4), 69.0 (CH-g), 62.4 (C-6), 31.3 (CH2-h). 10.1
Compound 8b was treated as described in Section 3.3.2 to give
the title compound as a yellow solid (27 mg, 99%); dH (600 MHz,
CD3OD): 8.57 (1H, s, H-e), 6.29 (1H, d, J1,2 5.8 Hz, H-1), 4.32 (1H,
t, J2,3 = J3,4 9.3 Hz, H-3), 3.98 (1H, dd, J1,2 5.8 Hz, J2,3 9.3 Hz, H-2),
3.84 (1H, m, H-5), 3.77 (1H, br d, J6a,6b 12.3 Hz, H-6a), 3.69 (1H,
dd, J5,6 4,8 Hz, J6a,6b 12.3 Hz, H-6b), 3.51 (1H, t, J3,4 = J4,5 9.3 Hz,

S. Dedola et al. / Carbohydrate Research 345 (2010) 1123–1134
1133
(CH3-i); HR ESI-MS found m/z 290.1349 [M+H]+; calcd for
C11H19N3O6ÁH 290.1347
3.6.2. Sweet almond b-glucosidase inhibition assay51
Sweet almond b-glucosidase activity was assessed by continu-
ous spectrophotometric assays at 400 nm performed in 96-well
plates at 37 °C in pH 6.5 buffer (20 mM AcONa, 10 mM PIPES,
0.1 mM EDTA, 2% DMSO, 0.002% w/v NaN3). The incubation mix-
3.5.19. 1-(b-
D-Glucopyranosyl)-4-(3-hydroxypropyl)-[1,2,3]-
triazole (16)
tures included b-glucosidase (5
lg/mL), p-nitrophenyl b-D-gluco-
Prepared from azide 31 and pent-4-yn-1-ol according to Meth-
od C as a white solid (27 mg, 68%) dH (600 MHz, CD3OD): 7.96 (1H,
s, H-e), 5.60 (1H, d, J1,2 9.2 Hz, H-1), 3.89 (2H, m, H-2, H-6a), 3.70
(1H, dd, J5,6 5.4 Hz, J6a,6b 12.0 Hz, H-6b), 3.60 (2H, t, Jh,i 6.6 Hz,
CH2-i), 3.56 (2H, m, H-3, H-5) 3.49 (1H, t, J3,4 = J4,5 9.2 Hz, H-4),
2.79 (2H, Jg,h 7.8 Hz, CH2-g), 1.89 (2H, m, CH2-h); dC (150 MHz,
CD3OD): 148.8 (C-f), 122.5 (C-e), 89.5 (C-1), 81.1 (C-3 or C-5),
78.5 (C-3 or C-5), 74.0 (C-2), 70.9 (C-4), 62.3 (C-6), 62.0 (C-i) 33.2
(C-g). 22.7 (C-h); HR ESI-MS found m/z 290.1348 [M+H]+; calcd
for C11H19N3O6ÁH 290.1347.
pyranoside (625 M) and inhibitor.
l
Acknowledgements
This work was supported by the UK BBSRC and the University of
East Anglia.
Supplementary data
Crystallographic information and structural diagrams for 24 and
27 have been provided as supplementary data with this paper. Full
crystallographic details, excluding structure features, have been
deposited (Deposition Nos. CCDC 767414–767415) with the Cam-
bridge Crystallographic Data Centre. These data may be obtained,
on request, from The Director, CCDC, 12 Union Road, Cambridge
CB2 1EZ, UK (tel.: +44 1223 336408; fax: +44 1223 336033; e-mail:
deposit@ccdc.cam.ac.uk or http://www.ccdc.cam.ac.uk). Supple-
mentary data associated with this article can be found, in the on-
line version, at doi:10.1016/j.carres.2010.03.041.
3.5.20. 1-(b-
D-Glucopyranosyl)-4-(4-hydroxybutyl)-[1,2,3]-
triazole (17)
Prepared from azide 31 and hex-5-yn-1-ol according to Method
C as a white solid (58 mg, 90%) dH (600 MHz, CD3OD): 7.97 (1H, s,
H-e), 5.57 (1H, d, J1,2 9.0 Hz, H-1), 3.87 (2H, m, H-2, H-6a), 3.70 (1H,
dd, J5,6 5.4 Hz, J6a,6b 12.0 Hz, H-6b), 3.58 (3H, m, H-3, H-5, CH2-l),
3.49 (1H, t, J3,4 = J4,5 9.0 Hz, H-4), 2.74 (2H, Jg,h 7.8 Hz, CH2-g),
1.74 (2H, m, CH2-h), 1.58 (2H, m, CH2-i); dC (150 MHz, CD3OD):
149.2 (C-f), 122.5 (C-e), 89.5 (C-1), 81.0 (C5), 78.5 (C-3), 73.9 (C-
2), 70.8 (C-4), 64.4 (C-l), 62.5 (C-6), 62.0 (C-i) 33.9 (C-g). 26.7 (C-
h); HR ESI-MS found m/z 304.1504 [M+H]+; calcd for C12H21N3O6ÁH
304.1503.
References
1. Heightman, T. D.; Vasella, A. T. Angew. Chem., Int. Ed. 1999, 38, 750–770.
2. Gloster, T. M.; Davies, G. J. Org. Biomol. Chem. 2010, 8, 305–320.
3. Lillelund, V. H.; Jensen, H. H.; Liang, X. F.; Bols, M. Chem. Rev. 2002, 102, 515–
553.
4. Granier, T.; Vasella, A. Helv. Chim. Acta 1995, 78, 1738–1746.
5. Kolb, H. C.; Finn, M. G.; Sharpless, K. B. Angew. Chem., Int. Ed. 2001, 40, 2004–
2021.
6. Meldal, M.; Tornoe, C. W. Chem. Rev. 2008, 108, 2952–3015.
7. Dedola, S.; Nepogodiev, S. A.; Field, R. A. Org. Biomol. Chem. 2007, 5, 1006–1017.
8. Dondoni, A. Chem. Asian J. 2007, 2, 700–708.
9. Nepogodiev, S. A.; Dedola, S.; Marmuse, L.; de Oliveira, M. T.; Field, R. A.
Carbohydr. Res. 2007, 342, 529–540.
10. Billing, J. F.; Nilsson, U. J. J. Org. Chem. 2005, 70, 4847–4850.
11. Chittaboina, S.; Xie, F.; Wang, Q. Tetrahedron Lett. 2005, 46, 2331–2336.
12. Hotha, S.; Kashyap, S. J. Org. Chem. 2006, 71, 364–367.
13. Gao, Y. J.; Eguchi, A.; Kakehi, K.; Lee, Y. C. Bioorg. Med. Chem. 2005, 13, 6151–
6157.
14. Fernandez-Megia, E.; Correa, J.; Rodriguez-Meizoso, I.; Riguera, R.
Macromolecules 2006, 39, 2113–2120.
15. Ning, X. H.; Guo, J.; Wolfert, M. A.; Boons, G. J. Angew. Chem., Int. Ed. 2008, 47,
2253–2255.
3.5.21. 1-(b-
D-Glucopyranosyl)-4-(2-carboxyethyl)-[1,2,3]-
triazole (18)
Prepared from azide 31 and pent-4-ynoic acid according to
Method C as a white solid (16 mg, 38%); dH (600 MHz, CD3OD):
7.99 (1H, s, H-e), 5.60 (1H, d, J1,2 9.4 Hz, H-1), 3.89 (2H, m, H-2,
H-6a), 3.70 (1H, dd, J5,6 5.4 Hz, J6a,6b 12.0 Hz, H-6b), 3.57 (2H, m,
H-3, H-5), 3.49 (1H, t, J3,4 = J4,5 9.4 Hz, H-4), 2.71 (2H, m, CH2-g),
2.38 (2H, m, CH2-h), 1.98 (2H, m, CH2-i); dC (150 MHz, CD3OD):
148.7 (C-f), 122.7 (C-e), 89.6 (C-1), 81.1 (C-3 or C5), 78.5 (C-3 or
C5), 74.0 (C-2), 70.9 (C-4), 64.4 (CH2-i) (CH-g), 62.4 (C-6), 26.0
(CH2-h), 25.7 (CH3-g); HR ESI-MS found m/z 304.1140 [M+H]+;
calcd for C11H17N3O7ÁH 304.1139.
3.6. Enzymatic assays
16. Laughlin, S. T.; Baskin, J. M.; Amacher, S. L.; Bertozzi, C. R. Science 2008, 320,
664–667.
17. Perion, R.; Ferreires, V.; Garcia-Moreno, M. I.; Mellet, C. O.; Duval, R.;
Fernandez, J. A. C.; Plusquellec, D. Tetrahedron 2005, 61, 9118–9128.
18. Rossi, L. L.; Basu, A. Bioorg. Med. Chem. Lett. 2005, 15, 3596–3599.
19. Zhou, Y.; Zhao, Y.; O’Boyle, K. M.; Murphy, P. V. Bioorg. Med. Chem. Lett. 2008,
18, 954–958.
20. Nguyen, M.; Folkman, J.; Bischoff, J. J. Biol. Chem. 1992, 267, 26157–26165.
21. Pili, R.; Chang, J.; Partis, R. A.; Mueller, R. A.; Chrest, F. J.; Passaniti, A. Cancer Res.
1995, 55, 2920–2926.
All the enzymes used in this study were purchased from Sigma
Chemical Co. Ltd, and were the purest forms available. The enzyme
concentrations were chosen so that the 20% of hydrolysis was
reached in 20 min and the assays were routinely run at 37 °C.
The library of compounds was screened at three different concen-
trations (1 mM, 100
lM and 10 lM), except DNJ which was also
screened at 1 M concentration. In order to avoid solubility issues
l
22. Dale, M. P.; Kopfler, W. P.; Chait, I.; Byers, L. D. Biochemistry 1986, 25, 2522–
2529.
23. Field, R. A.; Haines, A. H.; Chrystal, E. J. T.; Luszniak, M. C. Biochem. J. 1991, 274,
885–889.
24. Field, R. A.; Haines, A. H.; Chrystal, E. J. T. Bioorg. Med. Chem. Lett. 1991, 1, 667–
672.
25. Guo, W. F.; Hiratake, J.; Ogawa, K.; Yamamoto, M.; Ma, S. J.; Sakata, K. Bioorg.
Med. Chem. Lett. 2001, 11, 467–470.
with the more lipophilic triazoles and of the controls the assays
also contained 2% DMSO. The assay was performed in duplicate
and the two readings were averaged; replicates were typically
within 5–10% of each other.
a
-glucosidase inhibition assay54
26. Zou, W. Curr. Top. Med. Chem. 2005, 5, 1363–1391.
27. Iminosugars: From Synthesis to Therapeutic Applications; Compain, P., Martin, O.
R., Eds.; Wiley: Weinheim, 2007.
3.6.1. Yeast
Yeast -glucosidase activity was routinely assessed by a contin-
a
uous spectrophotometric assays at 400 nm performed in 96-well
plates at 37 °C in pH 6.8 buffer (20 mM AcONa, 10 mM PIPES,
0.1 mM EDTA, 2% DMSO, 0.002% w/v NaN3). The incubation mix-
28. Dedola, S.; Nepogodiev, S. A.; Hughes, D. L.; Field, R. A. Acta Crystallogr., Sect. C
2008, 64, O445–O446.
29. Tornoe, C. W.; Christensen, C.; Meldal, M. J. Org. Chem. 2002, 67, 3057–3064.
30. Rostovtsev, V. V.; Green, L. G.; Fokin, V. V.; Sharpless, K. B. Angew. Chem., Int. Ed.
2002, 41, 2596–2599.
tures included
a-glucosidase (5
lg/mL), p-nitrophenyl a-D-gluco-
31. Tropper, F. D.; Andersson, F. O.; Braun, S.; Roy, R. Synthesis 1992, 618–620.
pyranoside (200
l
M) and inhibitor.

1134
S. Dedola et al. / Carbohydrate Research 345 (2010) 1123–1134
32. Akula, R. A.; Temelkoff, D. P.; Artis, N. D.; Norris, P. Heterocycles 2004, 63, 2719–
2725.
33. Khanetskyy, B.; Dallinger, D.; Kappe, C. O. J. Comb. Chem. 2004, 6, 884–892.
34. Caddick, S. Tetrahedron 1995, 51, 10403–10432.
35. Chan, T. R.; Hilgraf, R.; Sharpless, K. B.; Fokin, V. V. Org. Lett. 2004, 6, 2853–
2855.
44. Xie, J.; Seto, C. T. Bioorg. Med. Chem. 2007, 15, 458–473.
45. Wilkinson, B. L.; Bornaghi, L. F.; Poulsen, S. A.; Houston, T. A. Tetrahedron 2006,
62, 8115–8125.
46. Temelkoff, D. P.; Norris, P.; Zeller, M. Acta Crystallogr., Sect. E 2004, 60, O1975–
O1976.
47. Briggs, A. J.; Glenn, R.; Jones, P. G.; Kirby, A. J.; Ramaswamy, P. J. Am. Chem. Soc.
36. Korytnyk, W.; Mills, J. A. J. Chem. Soc. 1959, 636–649.
37. Soli, E. D.; Manoso, A. S.; Patterson, M. C.; DeShong, P.; Favor, D. A.;
Hirschmann, R.; Smith, A. B. J. Org. Chem. 1999, 64, 3171–3177.
38. Bianchi, A.; Bernardi, A. J. Org. Chem. 2006, 71, 4565–4577.
39. Dondoni, A.; Marra, A. J. Org. Chem. 2006, 71, 7546–7557.
40. Jarosz, S.; Lewandowski, B.; Listkowski, A. Synthesis 2008, 913–916.
41. Brik, A.; Muldoon, J.; Lin, Y. C.; Elder, J. H.; Goodsell, D. S.; Olson, A. J.; Fokin, V.
V.; Sharpless, K. B.; Wong, C. H. Chembiochem 2003, 4, 1246–1248.
42. Lee, L. V.; Mitchell, M. L.; Huang, S. J.; Fokin, V. V.; Sharpless, K. B.; Wong, C. H. J.
Am. Chem. Soc. 2003, 125, 9588–9589.
1984, 106, 6200–6206.
48. Wolfe, S.; Whangbo, M. H.; Mitchell, D. J. Carbohydr. Res. 1979, 69, 1–26.
49. Himo, F.; Lovell, T.; Hilgraf, R.; Rostovtsev, V. V.; Noodleman, L.; Sharpless, K.
B.; Fokin, V. V. J. Am. Chem. Soc. 2005, 127, 210–216.
50. Wilkinson, B. L.; Bornaghi, L. F.; Houston, T. A.; Poulsen, S. A.; White, A. R. Acta
Crystallogr., Sect. E 2006, 62, O5065–O5067.
51. Dale, M. P.; Ensley, H. E.; Kern, K.; Sastry, K. A. R.; Byers, L. D. Biochemistry 1985,
24, 3530–3539.
52. Li, Y. K.; Byers, L. D. Biochim. Biophys. Acta 1989, 999, 227–232.
53. Hansen, L. D.; West, B. D.; Baca, E. J.; Blank, C. L. J. Am. Chem. Soc. 1968, 90,
6588–6592.
43. Srinivasan, R.; Li, J.; Ng, S. L.; Kalesh, K. A.; Yao, S. Q. Nat. Protocols 2007, 2,
2655–2664.
54. Halvorson, H.; Ellias, L. Biochim. Biophys. Acta 1958, 30, 28–40.