Synthesis and α-glucosidase inhibitory activity evaluation of N-substituted aminomethyl-β-d-glucopyranosides

Article abstract of DOI:10.1016/j.bmc.2013.06.002

A series of N-substituted 1-aminomethyl-β-d-glucopyranoside derivatives was prepared. These novel synthetic compounds were assessed in vitro for inhibitory activity against yeast α-glucosidase and both rat intestinal α-glucosidases maltase and sucrase. Mo

Full text of DOI:10.1016/j.bmc.2013.06.002

Bioorganic & Medicinal Chemistry xxx (2013) xxx–xxx
Contents lists available at SciVerse ScienceDirect
Bioorganic & Medicinal Chemistry
journal homepage: www.elsevier.com/locate/bmc
Synthesis and
a
-glucosidase inhibitory activity evaluation
of N-substituted aminomethyl-b-D-glucopyranosides q
⇑
Xiaoli Bian, Xiangni Fan, Changhu Ke, Yajun Luan, Guilan Zhao, Aiguo Zeng
College of Pharmacy, Xi’an Jiaotong University, No.76 Yanta West Road, Xi’an, Shaanxi Province 710061, People’s Republic of China
a r t i c l e i n f o
a b s t r a c t
Article history:
A series of N-substituted 1-aminomethyl-b-
D
-glucopyranoside derivatives was prepared. These novel
-glucosidase and both
-glucosidases maltase and sucrase. Most of the compounds displayed -glucosidase inhib-
itory activity, with IC50 values covering the wide range from 2.3 M to 2.0 mM. Compounds 19a
(IC50 = 2.3 M) and 19b (IC50 = 5.6 M) were identified as the most potent inhibitors for yeast -glucosi-
dase, while compounds 16 (IC50 = 7.7 and 15.6 M) and 19e (IC50 = 5.1 and 10.4 M) were the strongest
Received 26 April 2013
Revised 3 June 2013
Accepted 4 June 2013
Available online xxxx
synthetic compounds were assessed in vitro for inhibitory activity against yeast
rat intestinal
a
a
a
l
l
l
a
l
l
Keywords:
inhibitors of rat intestinal maltase and sucrase. Analysis of the kinetics of enzyme inhibition indicated
that 19e inhibited maltase and sucrase in a competitive manner. The results suggest that the amino-
methyl-b-D-glucopyranoside moiety can mimic the substrates of a-glucosidase in the enzyme catalytic
site, leading to competitive enzyme inhibition. Moreover, the nature of the N-substituent has consider-
a-Glucosidase
1-Aminomethyl-b-
Sugar mimic
Synthesis
D-glucopyranoside
able influence on inhibitory potency.
Ó 2013 The Authors. Published by Elsevier Ltd. All rights reserved.
1. Introduction
digestion and absorption of dietary starches has shown promise
in reducing PPHG, the burden of oxidative stress, and CVD.7–9
The prevalence of type 2 diabetes mellitus (T2DM) throughout
the world is increasing at an alarming rate. T2DM affects about
173 million people worldwide and is associated with vascular
complications that result in excess morbidity and mortality.1,2
Such complications include cardiovascular disease, stroke,
nephropathy, retinopathy, renal failure, and amputations.1,2 It is
now generally accepted that diabetes is a cardiovascular disease
(CVD) and that these cardiovascular complications are related to
prevailing hyperglycemia, particularly postprandial hyperglycemia
(PPHG). It is now established that PPHG per se is a strong risk fac-
tor for the development of CVD.3,4 PPHG has also been identified as
one of the earliest detectable abnormalities expressed in diabetes.
It is thus a better predictor for the progression of diabetes and has
been implicated in inducing the oxidative stress that is recognized
as a major pathophysiological link between CVD and diabetes.5,6
Pharmacological agents that specifically decrease PPHG, such as
These results can be achieved through dietary manipulation with
low glycemic-index food or by inhibition of the starch-digesting
enzyme
ders. Such
a
-glucosidase, which is present at the intestinal brush bor-
-glucosidase inhibitors (AGIs) retard carbohydrate
a
digestion and prolong overall carbohydrate digestion, slowing the
rate of glucose absorption and consequently blunting the post-
prandial plasma glucose increase.10,11 Several AGIs, including acar-
bose, voglibose, and miglitol (Fig. 1), have been used effectively in
the clinic to treat T2DM and to prevent CVD.12,13 But only a few
AGIs are available commercially, and some side-effects, such as
flatulence, occur due to treatment with a
-glucosidase inhibitors.14
Therefore, investigators have developed considerable interest in
the design and synthesis of specific glycosidase inhibitors of high
affinity.15,16
The structure of enzyme inhibitors usually resembles that of a
substrate, transition state, or product of an enzyme-catalyzed reac-
tion.17 Marketed AGIs all have structures similar to those of sugars.
For instance, acarbose and voglibose are amino sugars, and miglitol
a-glucosidase inhibitors (AGIs), may become therapeutics of colos-
sal importance. Food starches contribute to major postprandial
blood glucose, an issue that is of particular relevance to those of
Asian descent because of their specific dietary habits. Slowing
is an azasugar. Docking simulations of a-glucosidase inhibitors re-
vealed that the ammonium cation moieties of these amino sugar
and azasugar inhibitors exhibit strong electrostatic interactions
with amino acid residues, such as Asp, in the binding pocket. The
hydroxyl groups of these sugar analogs interact with amino
acid residues through hydrogen bonding. These interactions
appear to be very important for specific molecular recognition
and affinity. In recent years, various azasugars, amino sugars, and
q
This is an open-access article distributed under the terms of the Creative
Commons Attribution-NonCommercial-No Derivative Works License, which per-
mits non-commercial use, distribution, and reproduction in any medium, provided
the original author and source are credited.
⇑
Corresponding author. Tel./fax: +86 29 82657833.
E-mail address: agzeng@mail.xjtu.edu.cn (A. Zeng).
0968-0896/$ - see front matter Ó 2013 The Authors. Published by Elsevier Ltd. All rights reserved.
http://dx.doi.org/10.1016/j.bmc.2013.06.002
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2
X. Bian et al. / Bioorg. Med. Chem. xxx (2013) xxx–xxx
OH
OH
O
CH(OCH3)2
OH
OH
O
HO
O
O
OH
OH
HO
O
b
a
HO
OH
+
OH
HO
OH
OH
OH
OH
H
N
1
3
2
HO
HO
O
O
O
O
HO
O
HO
4
c
O
OH
O
OH
O
O
CH2NH2
HO
O
OH
CH2NO2
OH
OH
HO
5
acarbose
OH
H
N
Scheme 1. Synthesis of 1-aminomethyl-4,6-O-benzylidene-b-D-glucopyranoside 5.
Reagents and conditions: (a) p-TsOH, DMF, 60 °C, 5 h, 43.3%; (b) CH3NO2, DBU, THF,
N2, rt, 48 h, 83.3%; (c) HCOONH4, 10% Pd/C, MeOH, 65 °C, 3 h, 97.8%.
H
N
HO
HO
HO
HO
OH
R
O
OH
voglibose
OH
HO
HO
target compounds
OH
O
HO
OHC
HO
HO
OH
O
O
CH2NH2
a, b
R
+
OH
N
OH
miglitol
5
6a-6k
HO
OH
O
OH
O
HO
HO
HO
Figure 1. Structures of acarbose, voglibose, miglitol and target compounds.
O
O
c
N
N
H
R
H
R
OH
7a-7k
8a-8k
polyhydroxylated five- and six-membered cyclic compounds have
been studied intensively as structural analogs to monosaccharides.
These compounds have been investigated as potential inhibitors of
glycosidases.18–21 It was suggested that the introduction of certain
non-sugar moieties to the sugar structures can enhance inhibitory
activity owing to additional interactions with a hydrophobic pock-
et of the enzyme.21 In the search for simple, readily accessible com-
pounds that would still be efficient glycosidase inhibitors, we
prepared and assessed a series of N-substituted 1-aminomethyl-
R
R
8a
H
8g 4-OH
8b 2,4-diCl
8c 3,4-diCl
8d 4-F
8h 4-OMe
8i 3-OH,4-OMe
8j 3-OMe,4-OH
8k 2,4-diOMe
8e 3-NO2
8f 2-OH
Scheme 2. Synthesis of sugar–amines 8a–8k. Reagents and conditions: (a) EtOH,
reflux under N2, 3–10 h; (b) NaBH4, MeOH, rt, 30 min, 60–80%; (b) AcOH/H2O, 90 °C,
1 h, 28–40%.
b-
D
-glucopyranoside derivatives (Fig. 1). These sugar mimetics
O
OH
O
O
HO
were found to be
ity relationships of these compounds are also discussed.
a-glycosidase inhibitors, and the structure–activ-
O
O
OH
O
N
H
OH
7l
6l
O
O
OHC
S
O
2. Result and discussion
2.1. Chemistry
S
c
a, b
5
HO
NH
OH
6m
7m
O
O
O
O
OH
H
HO
N
H
The target compounds comprised two series according to the
structure of N-substituted moieties: the amino sugar analogues
and the amide sugar analogues. Both series were prepared from 1-
6n
7n
OH
aminomethyl-4,6-O-benzylidene-b-D-glucopyranoside (5) through
O
OH
HO
HO
OH
O
N
H
reductive amination or acylation, respectively (Fig. 2). Compound
5, the key intermediate for the preparation of target compounds,
was prepared according to procedures described in the literature.22
8l
OH
O
OH
The synthetic route is outlined in Scheme 1. Anhydrous D-glucose
1 was treated with benzaldehyde dimethyl acetal 2 and then
reacted with nitromethane in the presence of DBU to form 1-
nitromethyl-4,6-O-benzylidene-b-D-glucopyranoside 4. This com-
pound was then reduced with ammonium formate and Pd/C to give
intermediate 5.
A generalized synthetic approach to the amino sugar analogues
(8a–8n) is shown in Scheme 2 and Scheme 3. Intermediate 5 re-
acted with different aromatic aldehydes at reflux under N2 and
S
HO
HO
NH
8m
OH
O
OH
HO
HO
N
H
8n
Scheme 3. Synthesis of sugar–amines 81–8n. Reagents and conditions: (a) inter-
mediate 5, EtOH, reflux under N2, 3–10 h; (b) NaBH4, MeOH, rt, 30 min, 60–80%; (c)
AcOH/H2O, 33–43%.
then reduced with NaBH4 to give 7a–7n. These intermediates were
deprotected cleanly with AcOH/H2O to afford compounds 8a–8n.
The amido sugar analogues 11a–11m and 19a–19e were pre-
pared via the synthetic route shown in Schemes 4–6. Intermediate
5 was coupled with various substituted aromatic acids 9a–9m un-
der HOBt/EDCI/DIPEA conditions to form 10a to 10m. These inter-
mediates were deprotected with AcOH/H2O to give compounds
11a–11m (Scheme 4). The synthesis of the title compound 16
was completed as depicted in Scheme 5. The reaction of compound
5 with 3,4,5-triacetoxybenzoyl chloride 14 gave amide 15, which
OH
H(R)
O
HO
HO
N
H
Ar
OH
)
R
(
H
O
C
suger-amines
r
O
HO
A
O
OH
O
CH2NH2
a
OH
c
y
l
a
t
i
o
n
O
key intermediate 5
O
OH
HO
HO
N
H
Ar
suger-amides
Figure 2. The general structure of the target compounds and key intermediate 5.
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X. Bian et al. / Bioorg. Med. Chem. xxx (2013) xxx–xxx
3
O
HO
O
S
a
O
HO
5
O
OH
a
O
OH
O
R1-COOH
+
CH2NH2
O
O
CH2NH2
O
+
Cl
9a - 9m
O
5
20
OH
O
O
O
O
OH
O
O
OH
O
S
HO
HO
N
H
R1
O
HO
b
O
HO
N
H
R1
R1
O
HO
S
b
OH
N
HO
N
H
O
OH
OH
22
O
10a -10m
11a -11m
H
R1
21
11a Ph
11h 4-OHPh
11b 2,4-diClPh
11c 4-FPh
11i 4-OMePh
11j 2,4-diOMe
11k 4-OAcPh
11l 2-furan
Scheme 7. Synthesis of target compound 22. Reagents and conditions: (a) TEA,
DMF–DCM, rt, 70%; (b) AcOH/H2O, 90 °C, 1 h, 54.7%.
11d 3-NO2Ph
11e 4-NO2Ph
11f 2-OHPh
11g 2-OMePh
11m 2-Thiophene
2.0 mM, suggesting that the nature of the N-substituents had sig-
nificant effects on the inhibitory potencies.
Scheme 4. Synthesis of sugar–amides 11a–11m. Reagents and conditions: (a)
HOBt, EDCI, DIPEA, DMF, rt, 2 h; (d) AcOH/H2O, 90 °C, 1 h, 35–56%.
In the amino sugar series, 8a exhibited strong inhibitory activity
against yeast
substituents on the aromatic ring (8b–8l) noticeably decreased po-
tency, with the exception of 8e (IC50 = 44.3 M), which bears a ni-
tro group at the C3 position of the phenyl ring. The presence of 3,4-
dichloro (8c, IC50 = 613.3 M) or 2,4-dimethoxy substituents (8k,
IC50 = 622.1 M) decreased potency by about 16-fold. This result
may indicate that bulky groups on the aromatic ring are disadvan-
tageous for yeast -glucosidase inhibitory activity. Replacement of
a-glucosidase (IC50 = 39.2 lM). The introduction of
l
O
O
O
HO
HO
AcO
AcO
AcO
AcO
OH
OH
a
b
c
Cl
l
5
l
OAc
13
OH
OAc
14
12
a
OH
O
the phenyl ring with thiophene (8m) or cinnamoyl (8n) also atten-
O
O
O
HO
O
O
OAc
OAc
uated potency as compared with 8a.
HO
d
OAc
OAc
N
H
HO
N
H
OH
OH
The sugar–amine compounds showed different inhibition pro-
files against rat intestinal
for yeast -glucosidase. Compounds 8a and 8e, good inhibitors of
yeast -glucosidase, displayed weaker activity on maltase than
a-glucosidase from what were observed
OAc
OAc
15
16
a
a
Scheme 5. Synthesis of sugar–amide 16. Reagents and conditions: (a) Py., Ac2O, rt,
overnight, 78%; (b) SOCl2, DMF, DCM, reflux, 3 h, 94%; (c) TEA, DMF–DCM, rt, 75%;
(d) AcOH/H2O, 90 °C, 1 h, 54.7%.
did other sugar–amine analogues. Compound 8e was also the least
potent of the sugar-amine analogues against sucrase. Substitution
of the aromatic ring gave compounds (8b–8l), with clearly en-
hanced potency against maltase over that of 8a; however, the
IC50 values were greater than 100 lM. It is interesting that the
underwent deprotection to give 16. The treatment of compound 5
with cinnamic acid or substituted cinnamic acids in presence of
HOBt/EDCI gave intermediates 18a–18e. Subsequent deprotection
afforded compounds 19a–19e (Scheme 6). A similar procedure
employing para-toluenesulfonyl chloride was used to prepare sul-
fonamide 22 (Scheme 7).
introduction of bulky groups to aromatic ring led to enhanced
activity, as evidenced by the IC50 values of 8b, 8c, 8j and 8k. These
compounds were found to be between 6–11-fold more potent than
8a. It is worth noting that the N-cinnamyl derivative 8n appeared
to be a dual inhibitor of both maltase and sucrase, with IC50 values
of 121.3 and 97.4 lM, respectively.
The synthesized amido sugar series mainly comprises benzam-
ide (11a–11m, 16) and cinnamide derivatives (19a–11e). The cin-
namic amide derivatives 19a and 19b were most potent against
2.2. Biological activity
2.2.1.
The activity of the synthesized compounds was evaluated
in vitro against yeast -glucosidase from Saccharomyces cerevisiae
and rat intestinal -glucosidase (maltase and sucrase). The
a-Glucosidase inhibitory activity
yeast
a-glucosidase, with IC50 values of 2.3 and 5.6 lM, respec-
tively. Altering the substitution pattern of the aromatic ring on
the cinnamide unit led to sharply decreased activity, giving
compounds 2 orders of magnitude less potent than 19a and 19b.
Benzamides 11e and 11k showed strong inhibition of yeast
a
a
a
-glucosidase inhibitory activity was determined using methods
described in the literature.23–25 The results are expressed as the
inhibitor concentration required to achieve 50% inhibition of
a-glucosidase with IC50 values of 36.2 and 96.5 lM, respectively.
In comparing the effects of different aromatic ring substituents, it
seems that groups introduced at the 4-position have considerable
influence over activity. For instance, 11e and 11k were 14- and
a
-glucosidase activity (IC50) and are reported in Table 1. The IC50
data demonstrate that most of the synthesized compounds inhib-
ited
a
-glucosidase with IC50 values ranging from 2.3
lM
to
O
O
O
a
O
OH
CH2NH2
+
HO
OH
R2
5
17a-17e
OH
O
O
O
HO
O
O
HO
HO
b
O
N
N
H
R2
R2
OH
OH
18a - 18e
H
19a R2 = H
19b R2= 4-OH
19c R2= 4-OAc
19d R2= 3-OMe,4-OH
19e R2= 3,4-diOAc
Scheme 6. Synthesis of sugar–amides 19a-19e. Reagents and conditions: (a) HOBt, EDCI, DMF, rt, 2 h; (b) AcOH/H2O, 90 °C, 1 h, 30–50%.
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4
X. Bian et al. / Bioorg. Med. Chem. xxx (2013) xxx–xxx
Table 1
The IC50 data (Table 1) demonstrate that the target compounds
exhibit different inhibition profiles against -glucosidase from rat
intestine compared with -glucosidase from yeast. Some com-
pounds, such as 19a, 19b, 11e, 8a and 8e, were good inhibitors of
yeast -glucosidase but were not highly active against rat intesti-
nal -glucosidase. Alternatively, compounds 16 and 19e were
more effective against rat intestinal -glucosidase. They were
one to two orders of magnitude more potent against this enzyme
than against yeast -glucosidase. These results are not readily ex-
plained. However, a hypothesis may be based on the structural
classification of -glucosidases and the different amino acid se-
quences in the target binding sites. Chiba25 suggested that
-gluco-
sidases can be classified into two families, I and II, according to
their primary structures. Yeast -glucosidase shows similarities
in its amino acid sequence to family I, whereas the amino acid se-
quence of rat intestinal -glucosidase is highly conserved with that
of the -glucosidase family II. These differences in structure might
In vitro inhibitory activity of target compounds against a-glucosidases (IC50 l
M)a
a
a
Compd
Yeast
Rat intestine
Sucrase
Maltase
a
8a
8b
8c
8d
8e
8f
8g
8h
8i
8j
8k
8l
8m
8n
11a
11b
11c
11d
11e
11f
11g
11h
11i
11j
11k
11l
11m
16
19a
19b
19c
19d
19e
22
39.2 1.2
1326.4 13.4
115.7 2.8
221.4 6.2
202.5 5.2
714.2 12.8
383.5 7.8
171.7 4.7
306.3 7.1
407.4 7.9
222.7 4.5
160.1 2.8
393.2 9.9
324.2 7.6
121.3 2.3
842.2 12.4
585.4 14.1
463.8 8.33
261.5 4.9
846.4 15.2
1014.7 17.8
719.2 14.2
757.8 13.1
831.4 13.5
160.1 3.1
165.2 2.6
926.5 11.9
445.3 10.1
7.7 0.1
270.5 6.4
154.3 3.1
144.3 2.5
301.1 5.2
627.2 9.6
181.5 4.3
124.4 3.1
179.5 3.4
185.8 4.5
186.3 5.1
105.2 1.9
106.8 1.7
172.6 3.1
97.4 2.3
a
317.6 8.5
613.3 12.2
115.4 4.6
44.3 1.5
a
a
155.6 4.3
149.3 3.6
457.2 9.4
465.4 8.9
377.3 14.1
622.1 13.5
184.4 5.5
373.5 13.8
116.2 3.6
499.2 14.2
466.3 13.0
1517.6 24.4
283.3 5.3
36.2 0.6
470.5 6.7
471.4 7.2
1912.5 21.4
231.3 4.1
1860.2 25.6
96.5 1.8
a
a
a
a
>2000
a
991.4 14.6
403.5 7.9
381.2 7.7
1003.4 14.5
>2000
1087.3 14.1
1640.8 20.6
795.3 15.2
>2000
explain the differences in the relative binding of different inhibi-
tors. This would suggest that certain effective inhibitors of yeast
a
-glucosidase may be inactive against rat intestinal
Alternatively, some compounds that might be inactive and ignored
in screens against yeast -glucosidase could be good inhibitors of
rat intestinal -glucosidase. The use of yeast -glucosidase inhibi-
tion assays to evaluate -glucosidase inhibitors may give false po-
sitive or false negative results. The results of our present study
support this viewpoint. Therefore, assessment of -glucosidases
from mammalian intestines may be more rational and judicious
for the evaluation of -glucosidase inhibitors.
a-glucosidase.
a
a
a
a
160.4 4.4
770.3 9.6
>2000
534.4 8.6
324.6 8.7
225.2 3.3
2.3 0.04
a
15.6 0.3
a
167.8 3.5
368.6 6.8
165.6 3.8
382.2 6.8
5.1 0.1
314.3 7.7
405.5 12.1
154.8 3.8
253.4 7.1
10.4 0.2
5.6 0.12
2.2.2. Kinetics of enzyme inhibition
142.2 4.1
101.8 1.9
355.4 6.9
101.2 12.2.1
235.1 3.89
Compound 19e was selected for further investigation on the
kinetics of enzyme inhibition against rat intestinal maltase and su-
crase. The enzymatic reaction was performed according to the
reaction conditions described in the literature.25 The Dixon plot
for maltase and sucrase in the presence of compound 19e is shown
in Figure 3. The kinetics show that 19e is a competitive inhibitor of
476.2 5.8
3.3 0.8
1416.7 24.8
0.4 0.005
Acarbose
a
The results summarized are the mean values of n = 3 for IC50 values.
5-fold more potent, respectively, than 11a. Alternatively, 11h was
only 0.3 times as active as 11a against yeast -glucosidase. In eval-
uating inhibition of rat intestinal -glucosidase, it was initially
a
a
noted that the gallamide derivative 16 and the caffeoyl amide
derivative 19e were the most potent inhibitors, with maltase IC50
values of 7.7
l
M and 5.1
lM, respectively, and sucrase IC50 values
of 15.9 and 10.4
l
M. These compounds were 2 orders of magnitude
more active than other compounds. Substitution of the aromatic
ring had a significant influence on inhibitory potency. In comparing
compounds 11a and 11k, it was noted that the presence of an acet-
oxy group at the C4 position of the aromatic ring led to a remark-
able increase in activity. The 3,4,5-triacetoxy motif (16) increased
activity more than 120-fold, suggesting that the acetoxy groups
play an important role. This conclusion can also be drawn from a
comparison of 19a with 19e. The favorable role of acetoxy groups
may be attributable to their H-bond accepting capabilities. The sul-
fonamide derivative 22 did not exhibit conspicuous inhibitory
activity, demonstrating that the replacement of carbonyl with sul-
fonyl did not enhance activity.
When comparing the amino sugar and amido sugar compounds
displaying equivalent N-substituents (e.g., 8a vs 11a, 8b vs 11b, 8n
vs 19a, etc.), the sugar–amine compounds were generally more po-
tent than the corresponding sugar–amide compounds. It is pre-
sumed that amino sugar compounds have greater binding
affinities for the enzyme than do amido sugars, as has been ob-
served for each of the clinical
a-glucosidase inhibitors possessing
Figure 3. Lineweaver–Burk plot analysis of kinetics of
compound 19e. (A) maltase; (B) sucrase. Inhibitor concentration:
j10.0 M; N 20.0 M.
a
-glucosidase inhibition by
amine structures. Additional data and further research are needed
ꢀ
control;
to confirm this hypothesis.17–21
l
l
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X. Bian et al. / Bioorg. Med. Chem. xxx (2013) xxx–xxx
5
maltase and sucrase, with Ki values of 4.8 and 17.1
l
M, respec-
4.1.2. 1-Nitromethyl-4,6-O-benzylidene-b-D-glucopyranoside
tively. This competitive inhibition indicates that 19e may bind to
the catalytic sites of these enzymes and compete with their pri-
mary substrates. Based on these results, we speculate that the
competitive interactions of the tested compounds may be attrib-
(4)22
Compound 4 was prepared according to the literature proce-
dure (mp 213–214 °C as reported).
uted to the 1-aminomethyl-b-D-glucopyranoside unit. This moiety
4.1.3. 1-Aminomethy-4,6-O-benzylidene-b-D-glucopyranoside
may imitate the substrates of the enzymes and bind to the catalytic
site, thus leading to inhibitory activity. However, differences in po-
tency among the target compounds suggests that this competitive
interaction may be highly sensitive to the nature of the N-substitu-
ent, resulting in a range of potencies.
(5)22
Compound 5 was prepared according to the literature proce-
dure (mp 233–235 °C as reported).
4.1.4. General procedure for synthesis of 8a–n
The appropriate aldehydes (1.78 mmol) was added to a solution
of 5 (500 mg, 1.78 mmol) in dry EtOH (15 ml) and refluxed at N2 for
3–10 h until the start material was consumed. Following the sol-
vent was evaporated, the residue was dissolved in MeOH (10 ml),
then NaBH4 (1.78 mmol) was added and the mixture was stirred
at rt for 30 min. After the solvent was evaporated, H2O (15 ml)
was added and the mixture was extracted with EtOAc (20 ml
ꢀ2). The organic phase was dried over anhydrous Na2SO4 and
the solvent was evaporated to give the crude products of interme-
diates 7a–n which were used directly for the next step without fur-
ther purification.
The 7a–n were dissolved in AcOH/H2O (15/10 ml) and stirred at
90 °C for 1 h. The solvent was evaporated under reduced pressure
and the crude product was purified by column chromatography
on silica-gel and eluted with increasing polarity gradient mixture
of chloroform and methanol to afford the corresponding target
product 8a–n.
3. Conclusion
In conclusion, several N-substituted 1-aminomethyl-b-
glucopyranoside derivatives were conveniently prepared. Most
of these novel compounds inhibited -glucosidases from yeast
and rat intestine (maltase and sucrase) with IC50 values covering
a wide range from 2.3 M to 2.0 mM in our assay. Compounds
19a and 19b were identified as the most potent inhibitors for
yeast -glucosidase, and compounds 16 and 19e were the stron-
D-
a
l
a
gest inhibitors of maltase and sucrase. These compounds are one
to two orders of magnitude more potent than any other com-
pound. Studies on the enzyme inhibition kinetics of 19e indi-
cated that target compound inhibits rat intestinal maltase and
sucrase in a competitive fashion. The collective results strongly
suggest that the aminomethyl-b-
important skeleton for -glucosidase inhibition. This core struc-
D-glucopyranoside moiety is an
a
ture exerts its activity through competitive interactions with
the enzyme catalytic site. Alteration of the N-substituent has a
significant influence on activity, indicating that potency also
depends on the structural features of the N-substituents. This
suggests that additional interactions with appropriate N-substit-
uents with enzyme contribute considerably to inhibitory
potency. Further studies directed toward the enhancement of
inhibitory activity will focus on the variation of the N-substitu-
ents through replacement of the aromatic moiety with different
chain structures. The effects of compounds 16 and 19e on post-
prandial blood glucose are being tested in mammalian animal
models.
4.1.4.1. N-(b-D-Glucopyranosylmethyl)benzylamine (8a). Yield
38% from 5, a white amorphous powder. 1H NMR (400 MHz, DMSO-
d6): d 7.21–7.35 (m, 5H, Ph0), 3.68–3.77 (m, 2H, CH2-Ph0), 3.65 (t,
1H, J = 11.6 Hz, H-6b), 3.33–3.37 (m, 1H, H-6a), 3.09–3.18 (m, 3H,
H-3, H-4, H-5), 3.04 (t, 1H, J = 9.2 Hz, Glu-CH), 2.91–2.97 (m, 2H,
H-1, H-2), 2.81 (d, 1H, J = 10.4 Hz, Glu-CH). Anal. Calcd for
C14H21NO5: C, 59.35; H, 7.47; N, 4.94. Found: C, 59.32; H, 7.49; N,
4.96.
4.1.4.2. N-(b-
D
-Glucopyranosylmethyl)-2,4-dichloro benzyl-
amine (8b).
Yield 28% from 5, a white amorphous powder.
1H NMR (400 MHz, DMSO-d6): d 7.41–7.57 (m, 3H, Ph0), 3.71–
3.81 (m, 2H, –CH2Ph0), 3.64 (d, 1H, J = 11.2 Hz, H-6b), 3.34–3.39
(m, 2H, H-6a, H-5), 3.10–3.16 (m, 2H, H-3, H-4), 3.05 (t, 1H,
J = 8.0 Hz, Glu-CH), 2.94–2.98 (m, 2H, H-1, H-2), 2.82 (d, 1H,
J = 11.6 Hz, Glu-CH). Anal. Calcd for C14H19Cl2NO5: C, 47.74; H,
5.44; Cl, 20.13; N, 3.98. Found: C, 47.72; H, 5.47; Cl, 20.09; N, 4.01.
4. Experimental
4.1. Chemistry
Unless otherwise noted, all materials were obtained from com-
mercial suppliers and used without further purification. The pro-
gress of the reactions was monitored by TLC using Qingdao
Haiyang Chemical Co. Ltd, HG/T2354-92 Silica Gel GF254. Purifica-
tions of compounds were made by flash column chromatography
using Qingdao Haiyang Chemical Co. Ltd, silica gel (100–200
mesh). 1H (400 MHz) and 13C NMR (100 MHz) spectra were re-
corded with a Bruker AV400 spectrometer,—chemical shifts were
recorded in ppm, tetra-methylsilane was used as the internal stan-
dard and coupling constants (J) were given in Hertz. Melting points
were recorded using Tech. Instrument Co. Ltd, XT-4 melting point
apparatus and were uncorrected. The percentates of halogen and
sulphur in some target compounds were obtained by the oxygen
flask combustion method.
4.1.4.3. N-(b-
amine (8c).
D
-Glucopyranosylmethyl)-3,4-dichloro benzyl-
Yield 32% from 5, a white amorphous powder.
1H NMR (400 MHz, DMSO-d6): d 7.40–7.58 (m, 3H, Ph0), 3.71–
3.81 (m, 2H, –CH2Ph0), 3.64 (d, 1H, J = 11.6 Hz, H-6b), 3.35–3.39
(m, 2H, H-6a, H-5), 3.12–3.18 (m, 2H, H-3, H-4), 3.05 (t, 1H,
J = 8.8 Hz, Glu-CH), 2.94–2.99 (m, 2H, H-1, H-2), 2.82(d, 1H,
J = 10.8 Hz, Glu-CH). Anal. Calcd for C14H19Cl2NO5: C, 47.74; H,
5.44; Cl, 20.13; N, 3.98. Found: C, 47.75; H, 5.47; Cl, 20.11; N, 3.97.
4.1.4.4. N-(b-
(8d).
D-Glucopyranosylmethyl)-4-fluoro benzylamine
Yield 30% from 5, a white amorphous powder. 1H NMR
(400 MHz, DMSO-d6): d 7.10–7.38 (m, 4H, Ph0), 3.62–3.74 (m, 4H,
CH2-Ph0, H-6a, H-6b), 3.33–3.38 (m, 1H, H-5), 3.09–3.15 (m, 2H,
H-3, H-4), 3.04 (t, 1H, J = 6.8 Hz, Glu-CH), 2.92–2.97 (m, 2H, H-1,
H-2), 2.78 (d, 1H, J = 11.2 Hz, Glu-CH). Anal. Calcd for C14H20FNO5:
C, 55.81; H, 6.69; F, 6.31; N, 4.65. Found: C, C, 55.83; H, 6.70; F,
6.33; N, 4.67.
4.1.1. 4,6-O-Benzylidene-glucose (3)22
Compound 3 was prepared according to the literature proce-
dure (mp 176–178 °C as reported).
Please cite this article in press as: Bian, X.; et al. Bioorg. Med. Chem. (2013), http://dx.doi.org/10.1016/j.bmc.2013.06.002

6
X. Bian et al. / Bioorg. Med. Chem. xxx (2013) xxx–xxx
4.1.4.5. N-(b-
(8e).
D
-Glucopyranosylmethyl)-3-nitro benzylamine
4.1.4.12. N-(b-
D
-Glucopyranosylmethyl)-3-hydroxy-4-methoxy
Yield 35% from 5, a white amorphous powder. 1H NMR
benzylamine (8l).
Yield 43% from 5, a white amorphous pow-
1
(400 MHz, DMSO-d6): d 8.21 (s, 1H, 4-Ph0), 8.09 (d, 1H, J = 8.4 Hz,
2-Ph0), 7.80 (d, 1H, J = 7.2 Hz, 6-Ph0), 7.61 (t, 1H, J = 8.0 Hz, 5-Ph0),
3.79–3.89 (m, 2H, CH2-Ph0), 3.64 (d, 1H, J = 11.2 Hz, H-6b), 3.34–
3.39 (m, 2H, H-6a, H-5), 3.07–3.18 (m, 2H, H-3, H-4), 3.05 (t, 1H,
J = 8.8 Hz, Glu-CH), 2.92–2.97 (m, 2H, H-1, H-2), 2.80 (d, 1H,
J = 11.6 Hz, Glu-CH). Anal. Calcd for C14H20N2O7: C, 51.22; H,
6.14; N, 8.53. Found: C, 51.22; H, 6.11; N, 8.55.
der. H NMR (400 MHz, DMSO-d6): d 6.89–6.93 (m, 1H, 6-Ph0),
6.22–6.30 (m, 2H, 2-Ph0, 5-Ph0), 3.80–3.90 (m, 1H, CH-Ph0), 3.66
(s, 3H, -OCH3), 3.64 (m, 1H, H-6b), 3.37 (m, 1H, H-6a), 3.05–3.20
(m, 3H, H-3, H-4, H-5), 2.78–2.97 (m, 3H, Glu-CH, H-1, H-2), 2.41
(t, 1H, J = 9.2 Hz, Glu-CH), 1.27–1.31 (m, 3H, –CH3). Anal. Calcd
for C16H25NO7: C, 55.97; H, 7.34; N, 4.08. Found: C, 55.99; H,
7.36; N, 4.06.
4.1.4.6. N-(b-
(8f).
D
-Glucopyranosylmethyl)-2-hydroxy benzylamine
4.1.4.13.
amine (8m).
N-(b-
D
-Glucopyranosylmethyl)-thiophen-2-methyl-
Yield 31% from 5, a white amorphous powder. 1H NMR
Yield 38% from 5, a white amorphous powder.
(400 MHz, DMSO-d6): d 7.05–7.07 (m, 2H, 4-Ph0, 6-Ph0), 6.67–6.73
(m, 1H, 3-Ph0, 5-Ph0), 3.63–3.92 (m, 4H, CH2-Ph0, H-6a, H-6b),
3.36 (dd, 1H, J1 = 6.4 Hz, J2 = 11.2 Hz, H-5), 3.05–3.19 (m, 3H, Glu-
CH, H-3, H-4), 2.92–2.98 (m, 2H, H-1, H-2), 2.85–2.90 (m, 1H,
Glu-CH). Anal. Calcd for C14H21NO6: C, 56.18; H, 6.07; N, 4.68.
Found: C, 56.20; H, 6.05; N, 4.67.
1H NMR (400 MHz, DMSO-d6): d 7.37 (s, 1H, thiophene), 6.95 (s,
2H, thiophene), 3.63–3.94 (m, 4H, CH2-Ph0, H-6a, H-6b), 3.33–
3.38 (m, 1H, H-5), 3.09–3.17 (m, 2H, Glu-CH, H-4), 3.05 (t, 1H,
J = 6.8 Hz, H-3), 2.90–2.97 (m, 2H, H-1, H-2), 2.85 (d, 1H,
J = 12.0 Hz, Glu-CH). Anal. Calcd for C12H19NO5S: C, 49.81; H,
6.62; N, 4.84; S, 11.08. Found: C, 49.83; H, 6.67; N, 4.86; S, 11.09.
4.1.4.7. N-(b-
(8g).
Yield 35% from 5, a white amorphous powder. 1H NMR
(400 MHz, DMSO-d6):
9.20 (s, 1H, -Ph0-OH), 7.09 (d, 2H,
D
-Glucopyranosylmethyl)-4-hydroxy benzylamine
4.1.4.14.
(8n).
N-(b-
D
-Glucopyranosylmethyl)-cinnamyl
amine
Yield 33% from 5, a white amorphous powder. 1H NMR
d
(400 MHz, DMSO-d6): d 7.42 (d, 2H, J = 7.6 Hz, 2-Ph0, 6-Ph0), 7.32
(d, 2H, J = 7.6 Hz, 3-Ph0, 5-Ph0), 7.22 (t, 1H, J = 7.6 Hz, 4-Ph0), 6.52
(d, 1H, J = 16.0 Hz, C=CH–Ph0), 6.29–6.35 (m, 1H, HC@C–Ph0), 4.89
(t, 2H, CH2–C@C–Ph0), 4.48 (t, 1H, J = 6.0 Hz, H-6b), 3.65 (dd, 1H,
J1 = 7.2 Hz, J2 = 11.6 Hz, H-6a), 3.32 (m, 1H, H-5), 3.13–3.18 (m,
2H, H-3, H-4), 3.05 (t, 1H, J = 9.2 Hz, Glu-CH), 2.95–2.99 (m, 2H,
H-1, H-2), 2.86 (d, 1H, J = 11.6 Hz, Glu-CH). Anal. Calcd for
J = 10.8 Hz, 2-Ph0, 6-Ph0), 6.68 (d, 2H, J = 10.8 Hz, 3-Ph0, 5-Ph0),
3.52–3.65 (m, 3H, H-6b, –CH2Ph0), 3.34 (dd, 1H, J1 = 8.4 Hz,
J2 = 15.2 Hz, H-6a), 3.01–3.17 (m, 4H, H-5, H-4, H-3, Glu-CH),
2.92–2.98 (m, 2H, H-1, H-2), 2.76–2.80 (m, 1H, Glu-CH). 13C NMR
(100 MHz, DMSO-d6): d 155.6, 131.0, 129.7, 115.3 (C-Ph0), 82.1
(C-1), 78.6 (C-5), 78.5 (C-3), 73.1 (C-2), 71.0 (C-4), 62.2 (C-6),
53.1 (CH2Ph0), 51.0 (Glu-CH). Anal. Calcd for C14H21NO6: C, 56.18;
H, 6.07; N, 4.68. Found: C, 56.15; H, 6.09; N, 4.64.
C16H23NO5: C, 62.12; H, 7.49; N, 4.53. Found: C, 62.15; H, 7.51;
N, 4.51.
4.1.4.8. N-(b-
D
-Glucopyranosylmethyl)-4-methoxy benzylamine
4.1.5. General procedure for synthesis of 11a–m and 19a–e
To a solution of the appropriate substituted carboxylic acids
(9a–m) (1.78 mmol) in DMF (15 ml), following reagents were
added: HOBt (2.67 mmol), EDCI (2.67 mmol) and N,N-diisopropyl-
ethylamine (5.34 mmol). The mixture was stirred at rt. for 2 h, then
5 (500 mg, 1.78 mmol) was added and continued to stir until the
reaction completed. H2O (15 ml) was added and the mixture was
extracted with EtOAc (2 ꢀ 30 ml). The organic phase was washed
with saturated brine, dried over anhydrous Na2SO4, filtered and
concentrated. The crude products of 10a–m were obtained and
they were applied directly to the next step without further
purification.
The intermediates 10a–m underwent the same deprotection
procedure as described in Section 4.1.4 to afford the corresponding
target compounds 11a–m. From 5 and cinnmic acid or substituted
cinnmic acids 12a–e, the compounds 19a–e were prepared
through the similar procedure described above.
(8h). The reaction produced 8e in a 34% yield (two steps) as
amorphous powder. 1H NMR (400 MHz, DMSO-d6): d 7.25 (d, 2H,
2-Ph0, 6-Ph0), 6.86 (d, 2H, 3-Ph0, 5-Ph0), 3.73 (s, 3H, -CH3), 3.62–
3.69 (m, 4H, CH2Ph0, H-6a, H-6b), 3.33–3.39 (m, 1H, H-5), 3.02–
3.17 (m, 3H, H-3, H-4, Glu-CH), 2.91–2.98 (m, 2H, H-1, H-2), 2.81
(d, 1H, J = 16.0 Hz, Glu-CH). Anal. Calcd for C15H23NO6: C, 57.50;
H, 7.40; N, 4.47. Found: C, 57.51; H, 7.38; N, 4.45.
4.1.4.9.
N-(b-
D-Glucopyranosylmethyl)-3-hydroxy-4-methoxy
benzylamine (8i).
Yield 40% from 5, a white amorphous pow-
der. 1H NMR (400 MHz, DMSO-d6): 6.68–6.83 (m, 3H, Ph0), 3.72 (s,
3H, –OCH3), 3.55–3.69 (m, 4H, CH2-Ph0, H-6a, H-6b), 3.35–3.39 (m,
1H, H-5), 3.01–3.14 (m, 3H, H-3, H-4, Glu-CH), 2.92–2.98 (m, 2H,
H-1, H-2), 2.78 (d, 1H, J = 9.6 Hz, Glu-CH). Anal. Calcd for
C15H23NO7: C, 54.70; H, 7.04; N, 4.25. Found: C, 54.71; H, 7.02; N,
4.26.
4.1.4.10. N-(b-
D
-Glucopyranosylmethyl)-3-methoxy-4-hydroxy
4.1.5.1. N-(b-D-Glucopyranosylmethyl)benzamide (11a). Yield
benzylamine (8j). Yield 42% from 5, a white amorphous powder.
1H NMR (400 MHz, DMSO-d6):d 6.69–6.89 (m, 3H, Ph0), 3.75 (s, 3H,
–OCH3), 3.60–3.66 (m, 3H, CH2-Ph0, H-6b), 3.35–3.39 (m, 1H, H-6b),
3.02–3.17 (m, 4H, H-5, H-4, H-3, Glu-CH), 2.92–2.96 (m, 2H, H-
1, H-2), 2.80 (d, 1H, J = 11.1 Hz, Glu-CH). Anal. Calcd for
42% from 5, a white solid. mp 222–224 °C. 1H NMR (400 MHz,
DMSO-d6): d 8.32 (s, 1H, –NH–), 7.83 (t, 2H, J = 7.6 Hz, 2-Ph0, 6-Ph0),
7.53 (t, 1H, J = 7.2 Hz, 4-Ph0), 7.47 (t, 2H, J = 7.6 Hz, 3-Ph0, 5-Ph0),
4.95–5.12(m, 3H, 2-OH, 3-OH, 4-OH), 4.44 (s, 1H, 6-OH), 3.85 (dd,
1H, J1 = 6.8 Hz, J2 = 11.2 Hz, H-6b), 3.67 (dd, 1H, J1 = 7.2 Hz,
J2 = 11.2 Hz, H-6a), 3.39–3.42 (m, 1H, H-5), 3.16–3.23 (m, 3H, Glu-
CH, H-3, H-4), 3.08 (t, 1H, J = 9.2 Hz, H-2), 3.02 (t, 1H, J = 9.2 Hz, H-
1), 2.92–2.98 (m, 1H, Glu-CH). Anal. Calcd for C14H19NO6: C, 56.56;
H, 6.44; N, 4.71. Found: C, 56.55; H, 6.41; N, 4.73.
C15H23NO7: C, 54.70; H, 7.04; N, 4.25. Found: C, 54.68; H, 7.06;
N, 4.26.
4.1.4.11. N-(b-
D-Glucopyranosylmethyl)-2, 4-dimethoxy benzyl-
amine (8k).
The reaction produced 8c in a 25% yield (two steps)
as amorphous powder. 1H NMR (400 MHz, DMSO-d6): d 7.19–6.47
(m, 3H, Ph0), 3.74–3.76 (m, 6H, 2ꢀ OCH3), 3.64 (m, 4H, H-6a, H-6b),
3.35–3.39 (m, 1H, H-5), 3.12–3.17 (m, 2H, H-3, H-4), 3.04 (t, 1H,
J = 10.6 Hz, Glu-CH), 2.94–2.97 (m, 2H, H-1, H-2), 2.82 (m, 1H,
Glu-CH). Anal. Calcd for C16H25NO7: C, 55.97; H, 7.34; N, 4.08.
Found: C, 56.01; H, 7.32; N, 4.06.
4.1.5.2. N-(b-
(11b).
D-Glucopyranosylmethyl)-2,4-dichloro benzamide
Yield 45% from 5, a white solid. mp 85–88 °C. 1H NMR
(400 MHz, DMSO-d6): d 8.39 (s, 1H, –NH–), 7.69 (s, 1H, 6-Ph0),
7.45–7.50 (m, 2H, 3-Ph0, 5-Ph0), 5.08 (d, 1H, J = 5.2 Hz, 2-OH),
4.97 (d, 1H, J = 3.6 Hz, 3-OH), 4.92 (d, 1H, J = 4.8 Hz, 4-OH), 4.34
(t, 1H, J = 7.2 Hz, 6-OH), 3.87 (dd, 1H, J1 = 6.8 Hz, J2 = 13.2 Hz,
Please cite this article in press as: Bian, X.; et al. Bioorg. Med. Chem. (2013), http://dx.doi.org/10.1016/j.bmc.2013.06.002

X. Bian et al. / Bioorg. Med. Chem. xxx (2013) xxx–xxx
7
H-6b), 3.64 (dd, 1H, J1 = 10.4 Hz, J2 = 19.6 Hz, H-6a), 3.37–3.39 (m,
1H, H-5), 3.13–3.17 (m, 2H, H-3, H-4), 3.05–3.09 (m, 2H, Glu-CH,
H-2), 2.97–3.02 (m, 2H, Glu-CH, H-1). Anal. Calcd for C14H17Cl2NO6:
C, 45.92; H, 4.68; N, 3.82. Found: C, 45.94; H, 4.67; N, 3.80.
2), 3.12–3.19 (m, 3H, Glu-CH, H-3, H-4), 2.98–3.07 (m, 2H, H-1,
Glu-CH). Anal. Calcd for C15H21NO7: C, 53.04; H, 6.47; N, 4.28.
Found: C, 53.07; H, 6.45; N, 4.25.
4.1.5.8. N-(b-
(11h).
D-Glucopyranosylmethyl)-4-hydroxy benzamide
4.1.5.3.
(11c).
N-(b-
D
-Glucopyranosylmethyl)-4-fluoro
benzamide
Yield 38% from 5, a white solid. mp 123–125 °C. 1H
Yield 38% from 5, a white solid. mp 247–249 °C. 1H
NMR (400 MHz, DMSO-d6): d 9.99 (s, 1H, Ph0-OH), 8.07 (s, 1H, –
NH–), 7.71 (d, 2H, J = 8.8 Hz, 2-Ph0, 6-Ph0), 6.78 (d, 2H, J = 8.4 Hz,
3-Ph0, 5-Ph0), 5.11 (d, 1H, J = 4.8 Hz, 2-OH), 4.94 (d, 1H, J = 4.4 Hz,
3-OH), 4.92 (d, 1H, J = 5.2 Hz, 4-OH), 4.44 (t, 1H, J = 6.0 Hz, 6-OH),
3.77 (dd, 1H, J1 = 6.8 Hz, J2 = 10.8 Hz, H-6b), 3.66 (dd, 1H,
J1 = 6.8 Hz, J2 = 10.8 Hz, H-6a), 3.40–3.43 (m, 1H, H-5), 3.16–3.18
(m, 3H, Glu-CH, H-3, H-4), 3.08 (t, 1H, J = 6.4 Hz, H-2), 2.89–3.00
(m, 2H, H-1, Glu-CH). Anal. Calcd for C14H19NO7: C, 53.67; H,
6.11; N, 4.47. Found: C, 53.65; H, 6.09; N, 4.49.
NMR (400 MHz, DMSO-d6): d 8.34 (s, 1H, –NH–), 7.91 (t, 2H,
J = 5.6 Hz, 2-Ph0, 6-Ph0), 7.29 (t, 2H, J = 8.4 Hz, 3-Ph0, 5-Ph0), 5.08
(d, 1H, J = 5.2 Hz, 2-OH), 4.94 (d, 1H, J = 4.4 Hz, 3-OH), 4.91 (d,
1H, J = 5.2 Hz, 4-OH), 4.41 (t, 1H, J = 5.6 Hz, 6-OH), 3.84 (dd, 1H,
J1 = 7.2 Hz, J2 = 12.0 Hz, H-6b), 3.66 (dd, 1H, J1 = 7.2 Hz,
J2 = 11.2 Hz, H-6a), 3.41–3.39 (m, 1H, H-5), 3.16–3.23 (m, 3H,
Glu-CH, H-3, H-4), 3.08 (t, 1H, J = 9.2 Hz, H-2), 3.02 (t, 1H,
J = 5.2 Hz, H-1), 2.92–2.98 (m, 1H, Glu-CH). Anal. Calcd for
C14H18FNO6: C, 53.33; H, 5.75; N, 4.44. Found: C, 53.37; H, 5.73;
N, 4.41.
4.1.5.9. N-(b-
(11i).
D-Glucopyranosylmethyl)-4-methoxy benzamide
Yield 40% from 5, a white solid. mp 242–244 °C. 1H
4.1.5.4.
(11d).
N-(b-
D
-Glucopyranosylmethyl)-3-nitro
benzamide
NMR (400 MHz, DMSO-d6): d 8.18 (s, 1H, –NH–), 7.83 (d, 2H,
J = 8.4 Hz, 2-Ph0, 6-Ph0), 6.99 (d, 2H, J = 8.8 Hz, 3-Ph0, 5-Ph0), 5.11
(d, 1H, J = 4.8 Hz, 2-OH), 4.95 (d, 1H, J = 4.8 Hz, 3-OH), 4.92 (d,
1H, J = 5.2 Hz, 4-OH), 4.44 (t, 1H, J = 6.0 Hz, 6-OH), 3.83 (dd, 1H,
J1 = 6.0 Hz, J2 = 11.2 Hz, H-6b), 3.81 (s, 3H, –OCH3), 3.66 (dd, 1H,
J1 = 7.2 Hz, J2 = 11.2 Hz, H-6a), 3.40–3.46 (m, 1H, H-5), 3.13–3.21
(m, 3H, Glu-CH, H-3, H-4), 3.08 (t, 1H, J = 8.4 Hz, H-2), 3.01 (t,
1H, J = 8.8 Hz, H-1), 2.90–2.94 (m, 1H, Glu-CH). Anal. Calcd for
Yield 35% from 5, a white solid. mp 190–192 °C. 1H
NMR (400 MHz, DMSO-d6) d 8.74 (s, 1H, –NH–), 8.67 (s, 1H, 2-
Ph0), 8.38 (d, 1H, J = 8.0 Hz, 4-Ph0), 8.28 (d, 1H, J = 7.6 Hz, 6-Ph0),
7.79 (t, 1H, J = 8.0 Hz, 5-Ph0), 5.10 (d, 1H, J = 5.2 Hz, 2-OH), 4.96
(d, 1H, J = 4.0 Hz, 3-OH), 4.92 (d, 1H, J = 5.6 Hz, 4-OH), 4.40 (t, 1H,
J = 6.0 Hz, 6-OH), 3.88 (dd, 1H, J1 = 6.0 Hz, J2 = 12.8 Hz, H-6b), 3.67
(dd, 1H, J1 = 7.2 Hz, J2 = 10.8 Hz, H-6a), 3.42 (m, 1H, H-5), 3.15–
3.28 (m, 3H, Glu-CH, H-3, H-4), 3.10 (t, 1H, J = 6.8 Hz, H-2), 2.94–
3.05 (m, 2H, H-1, Glu-CH). Anal. Calcd for C14H18N2O8: C, 49.12;
H, 5.30; N, 8.18. Found: C, 49.15; H, 5.29; N, 8.16.
C15H21NO7: C, 53.04; H, 6.47; N, 4.28. Found: C, 53.07; H, 6.45;
N, 4.30.
4.1.5.10. N-(b-
ide (11j).
D
-Glucopyranosylmethyl)-2,4-dimethoxy benzam-
4.1.5.5.
(11e).
N-(b-
D
-Glucopyranosylmethyl)-4-nitro
benzamide
Yield 47% from 5, a white solid. mp 133–135 °C. 1H
Yield 48% from 5, a white solid. mp 224–226 °C. 1H
NMR (400 MHz, DMSO-d6): d 8.28 (s, 1H, –NH–), 7.88 (d, 1H,
J = 8.8 Hz, 6-Ph0), 6.65 (d, 1H, J = 9.2 Hz, 5-Ph0), 6.63 (s, 1H, 3-Ph0),
5.16 (d, 1H, J = 5.6 Hz, 2-OH), 4.99 (d, 1H, J = 2.8 Hz, 3-OH), 4.96
(d, 1H, J = 5.2 Hz, 4-OH), 4.57 (t, 1H, J = 5.6 Hz, 6-OH), 3.93 (s, 3H,
OCH3-20), 3.82 (s, 3H, OCH3-40), 3.77 (dd, 1H, J1 = 5.2 Hz,
J2 = 8.8 Hz, H-6b), 3.72 (dd, 1H, J1 = 5.2 Hz, J2 = 12.8 Hz, H-6a),
3.44 (m, 1H, H-5), 3.27 (m, 1H, H-2), 3.12–3.19 (m, 3H, Glu-CH,
H-3, H-4), 2.99–3.07 (m, 2H, H-1, Glu-CH). Anal. Calcd for
NMR (400 MHz, DMSO-d6): d 8.67 (s, 1H, –NH–), 8.32 (d, 2H,
J = 8.0 Hz, 3-Ph0, 5-Ph0), 8.06 (d, 2H, J = 8.4 Hz, 2-Ph0, 6-Ph0), 5.11
(d, 1H, J = 5.2 Hz, 2-OH), 4.98 (d, 1H, J = 4.4 Hz, 3-OH), 4.93 (d,
1H, J = 5.2 Hz, 4-OH), 4.41 (t, 1H, J = 5.6 Hz, 6-OH), 3.88 (dd, 1H,
J1 = 6.0 Hz, J2 = 13.2 Hz, H-6b), 3.66 (dd, 1H, J1 = 7.6 Hz,
J2 = 10.8 Hz, H-6a), 3.39–3.44 (m, 1H, H-5), 3.14–3.26 (m, 3H,
Glu-CH, H-3, H-4), 3.09 (t, 1H, J = 9.2 Hz, H-2), 3.02 (t, 1H,
J = 8.8 Hz, H-1), 2.93–2.99 (m, 1H, Glu-CH). Anal. Calcd for
C16H23NO8: C, 53.78; H, 6.49; N, 3.92. Found: C, 53.80; H, 6.47;
C14H18N2O8: C, 49.12; H, 5.30; N, 8.18. Found: C, 49.15; H, 5.31;
N, 3.91.
N, 8.15.
4.1.5.11. N-(b-D-Glucopyranosylmethyl)-4-acetoxy benzamide
(11k).
Yield 56% from 5, a white solid. mp 172–174 °C. 1H
4.1.5.6. N-(b-D-Glucopyranosylmethyl)-2-hydroxy benzamide
(11f).
Yield 47% from 5, a white solid. mp 215–217 °C. 1H
NMR (400 MHz, DMSO-d6): d 8.34 (s, 1H, –NH–), 7.88 (d, 2H,
J = 8.0 Hz, 2-Ph0, 6-Ph0), 7.23 (d, 2H, J = 8.0 Hz, 3-Ph0, 5-Ph0), 5.10
(d, 1H, J = 5.2 Hz, 2-OH), 4.95 (d, 1H, J = 3.6 Hz, 3-OH), 4.92 (d,
1H, J = 5.2 Hz, 4-OH), 4.43 (t, 1H, J = 5.6 Hz, 6-OH), 3.85 (dd, 1H,
J1 = 5.2 Hz, J2 = 11.6 Hz, H-6b), 3.66 (dd, 1H, J1 = 4.8 Hz,
J2 = 12.8 Hz, H-6a), 3.37–3.42 (m, 1H, H-5), 3.17–3.24 (m, 3H,
Glu-CH, H-3, H-4), 3.08 (t, 1H, J = 8.8 Hz, H-2), 2.92–3.03 (m, 2H,
H-1, Glu-CH), 2.29 (s, 3H, –OAc). Anal. Calcd for C16H21NO8: C,
54.08; H, 5.96; N, 3.94. Found: C, 54.11; H, 5.98; N, 3.92.
NMR (400 MHz, DMSO-d6): d 12.25 (s, 1H, Ph0-OH), 8.66 (s, 1H, –
NH–), 7.88 (d, 1H, J = 8.0 Hz, 6-Ph0), 7.39 (t, 1H, J = 8.0 Hz, 4-Ph0),
6.88–6.92 (m, 2H, 3-Ph0, 5-Ph0), 5.09 (d, 1H, J = 5.2 Hz, 2-OH),
4.95 (d, 1H, J = 4.4 Hz, 3-OH), 4.91 (d, 1H, J = 4.8 Hz, 4-OH), 4.40
(t, 1H, J = 5.6 Hz, 6-OH), 3.86 (dd, 1H, J1 = 5.6 Hz, J2 = 11.2 Hz, H-
6b), 3.68 (dd, 1H, J1 = 6.8 Hz, J2 = 11.2 Hz, H-6a), 3.40–3.46 (m,
1H, H-5), 3.16–3.27 (m, 3H, Glu-CH, H-3, H-4), 3.10 (t, 1H,
J = 7.6 Hz, H-2), 2.95–3.05 (m, 2H, H-1, Glu-CH). Anal. Calcd for
C14H19NO7: C, 53.67; H, 6.11; N, 4.47. Found: C, 53.69; H, 6.10;
N, 4.45.
4.1.5.12. N-(b-D-Glucopyranosylmethyl) furoylamide (11l).
Yield
42% from 5, a white solid. mp 198–200 °C. 1H NMR (400 MHz, DMSO-
d6): d 8.12 (s, 1H, –NH–), 7.84 (s, 1H, 5-furan0), 7.13 (d, 1H, J = 3.2 Hz,
3-furan0), 6.63 (t, 1H, J = 1.6 Hz, 4-furan0), 5.11 (d, 1H, J = 5.2 Hz, 2-
OH), 4.96 (d, 1H, J = 5.6 Hz, 3-OH), 4.93 (d, 1H, J = 5.6 Hz, 4-OH), 4.48
(t, 1H, J = 5.6 Hz, 6-OH), 3.79 (dd, 1H, J1 = 6.8 Hz, J2 = 11.6 Hz, H-6b),
3.66 (dd, 1H, J1 = 7.2 Hz, J2 = 10.8 Hz, H-6a), 3.39–3.42 (m, 1H, H-5),
3.13–3.20 (m, 3H, Glu-CH, H-3, H-4), 3.08 (t, 1H, J = 9.2 Hz, H-2), 2.90–
3.03 (m, 2H, H-1, Glu-CH). Anal. Calcd for C12H17NO7: C, 50.17; H,
5.96; N, 4.88. Found: C, 50.15; H, 5.97; N, 4.90.
4.1.5.7. N-(b-D-Glucopyranosylmethyl)-2-methoxy benzamide
(11g).
Yield 45% from 5, a white solid. mp 154–156 °C. 1H
NMR (400 MHz, DMSO-d6): d 8.31 (s, 1H, –NH–), 7.85 (d, 1H,
J = 7.6 Hz, 6-Ph0), 7.49 (t, 1H, J = 7.2 Hz, 5-Ph0), 7.15 (d, 1H,
J = 8.4 Hz, 3-Ph0), 7.05 (t, 1H, J = 7.6 Hz, 4-Ph0), 5.16 (d, 1H,
J = 5.6 Hz, 2-OH), 4.99 (d, 1H, J = 4.4 Hz, 3-OH), 4.95 (d, 1H,
J = 5.2 Hz, 4-OH), 4.54 (m, 1H, J = 5.6 Hz, 6-OH), 3.91 (s, 3H, –
OCH3), 3.79 (dd, 1H, J1 = 5.2 Hz, J2 = 13.2 Hz, H-6b), 3.71(dd, 1H,
J1 = 5.2 Hz, J2 = 11.6 Hz, H-6a), 3.42 (m, 1H, H-5), 3.27 (m, 1H, H-
Please cite this article in press as: Bian, X.; et al. Bioorg. Med. Chem. (2013), http://dx.doi.org/10.1016/j.bmc.2013.06.002

8
X. Bian et al. / Bioorg. Med. Chem. xxx (2013) xxx–xxx
4.1.5.13. N-(b-
D
-Glucopyranosylmethyl)thienylamide (11m).
Yield
2H, 2-Ph0, 6-Ph0), 7.43 (d, 1H, J = 15.6 Hz, C@CH–Ph0), 7.31 (d, 1H,
50% from 5, a white solid. mp 224–225 °C. 1H NMR (400 MHz, DMSO-
J = 8.0 Hz, 5-Ph0), 6.71 (d, 1H, J = 15.6 Hz, HC@CH–Ph0), 5.10 (d,
1H, J = 5.2 Hz, 2-OH), 4.94–4.97 (m, 2H, 3-OH, 4-OH), 4.44 (m,
1H, 6-OH), 3.80 (dd, 1H, J1 = 6.4 Hz, J2 = 12.0 Hz, H-6b), 3.69 (dd,
1H, J1 = 6.0 Hz, J2 = 16.0 Hz, H-6a), 3.36 (m, 1H, H-5), 3.15–3.10
(m, 4H, H-4, H-2, H-3, Glu-CH), 2.94–3.03 (m, 2H, H-1, Glu-CH).
Anal. Calcd for C20H25NO10: C, 54.67; H, 5.73; N, 3.19. Found: C,
54.69; H, 5.71; N, 3.20.
0
d6): d 8.37 (s, 1H, –NH–), 7.81 (d, 1H, J = 3.2 Hz, 2-thiophene ), 7.76 (d,
0
0
1H, J = 5.2 Hz, 4-thiophene ), 7.15 (t, 1H, J = 8.4 Hz, 3-thiophene ), 5.07 (d,
1H, J = 5.2 Hz, 2-OH), 4.95 (d, 1H, J = 4.8 Hz, 3-OH), 4.91 (d, 1H, J = 5.2 Hz,
4-OH), 4.41 (t, 1H, J = 6.0 Hz, 6-OH), 3.81 (dd, 1H, J1 = 5.6 Hz, J2 = 11.6 Hz,
H-6b), 3.68 (dd, 1H, J1 = 7.2 Hz, J2 = 10.8 Hz, H-6a), 3.45 (m, 1H, H-5),
3.14–3.22 (m, 3H, Glu-CH, H-3, H-4), 3.11 (t, 1H, J = 8.4 Hz, H-2), 3.04–
3.29 (m, 2H, H1, Glu-CH). Anal. Calcd for C12H17NO6S: C, 47.52; H, 5.65;
N, 4.62; S, 10.57. Found: C, 47.56; H, 5.63; N, 4.60; S, 10.55.
4.1.6. 3,4,5-Triacetoxybenzoic acid (13)
Gallic acid (3.4 g, 20 mmol) was dissolved in acetic anhydride
(11.1 ml, 120 mmol) at 0 °C, then pyridine (2 ml) was added, and
the mixture was stirred at rt. overnight. The resulting mixture
was poured into ice-water, and neutralized to pH 2 with HCl and
extracted with EtOAc (30 ml ꢀ2). The organic phase was washed
with H2O and saturated brine, dried over Na2SO4, filtered and con-
centrated to get 13 as a white solid 4.6 g. Yield 78%. mp 170–
172 °C.
4.1.5.14. N-(b-
D
-Glucopyranosylmethyl) cinnamide (19a).
Yield
55% from 5, a white solid. mp 212–214 °C. 1H NMR (400 MHz,
DMSO-d6): d 8.09 (s, 1H, –NH–), 7.57 (d, 2H, J = 7.6 Hz, 2-Ph0, 6-Ph0),
7.44 (d, 1H, J = 15.6 Hz, C@CH–Ph0), 7.32–7.42(m, 3H, 3-Ph0, 4-Ph0, 5-
Ph0), 6.73 (d, 1H, J = 15.6 Hz, HC@CH–Ph0), 5.08 (d, 1H, J = 5.2 Hz, 2-
OH), 4.96 (d, 1H, J = 4.8 Hz, 3-OH), 4.94 (d, 1H, J = 5.6 Hz, 4-OH), 4.41
(t, 1H, J = 4.8 Hz, 6-OH), 3.79 (dd, 1H, J1 = 7.2 Hz, J2 = 12.8 Hz, H-6b),
3.69 (dd, 1H, J1 = 7.6 Hz, J2 = 11.2 Hz, H-6a), 3.39–3.46 (m, 1H, H-5),
3.07–3.18 (m, 4H, Glu-CH, H-2, H-3, H-4), 3.02 (t, 1H, H-1,
J = 9.2 Hz), 2.91–2.97 (m, 1H, Glu-CH). Anal. Calcd for C12H21NO6: C,
59.43; H, 6.65; N, 4.33. Found: C, 59.43; H, 6.66; N, 4.34.
4.1.7. 3,4,5-Triacetoxybenzoyl chloride (14)
To dissolve 13 (1.0 g, 3.38 mmol) in DCM (20 ml), SOCl2
(0.73 ml, 10.13 mmol) was added dropwise and a little of DMF
was added. The mixture was refluxed for 3 h. After the solvent
was evaporated under reduced pressure, white solid was obtained
which was recrystallized with carbon tetrachloride to afford com-
pound 14 1.0 g. Yield 94.2%. mp 106–107 °C.
4.1.5.15. N-(b-
D-Glucopyranosylmethyl)-4-hydroxy cinnamide
(19b).
Yield 45% from 5, a white solid. mp 236–238 °C. 1H
NMR 400 MHz, DMSO-d6): d 9.89 (s, 1H, –OH–Ph0), 7.98 (s, 1H, –
NH–), 7.39 (d, 2H, J = 8.0 Hz, 2-Ph0, 6-Ph0), 7.34 (d, 1H, J = 15.6 Hz,
C@CH–Ph0), 6.79 (d, 2H, J = 8.0 Hz, 3-Ph0, 5-Ph0), 6.51 (d, 1H,
J = 15.6 Hz, HC@CH-Ph0), 5.09 (d, 1H, J = 4.8 Hz, 2-OH), 4.94–4.96
(m, 2H, 3-OH, 4-OH), 4.44 (t, 1H, J = 6.0 Hz, 6-OH), 3.76 (dd, 1H,
J1 = 7.2 Hz, J2 = 11.6 Hz, H-6b), 3.67 (dd, 1H, J1 = 7.6 Hz,
J2 = 10.8 Hz, H-6a), 3.40–3.45 (m, 1H, H-5), 3.15–3.18 (m, 1H, H-
4), 3.12–3.08 (m, 3H, Glu-CH, H-2, H-3), 2.89–3.01 (m, 1H, Glu-
CH, H-1). Anal. Calcd for C126H21NO7: C, 56.63; H, 6.24; N, 4.13.
Found: C, 56.60; H, 6.22; N, 4.14.
4.1.8. N-(b-D-Glucopyranosylmethyl)-3,4-diacetoxy cinnamide
(15)
To a solution of 5 (400 mg, 1.42 mmol) in DMF/DCM (5 ml/
10 ml), triethylamine (0.4 ml, 2.84 mmol) was added. Then solu-
tion of 14 (447 mg, 1.42 mmol) in DMF was added at 0 °C slowly
to above mixture, stirred at rt. until the reaction completed. Re-
move the solvent and H2O (20 ml) was added, then the mixture
was extracted with EtOAc (30 ml ꢀ2). The organic phase was dried
and concentrated to give 15 as a white solid (600 mg, 75.5%), which
were used directly for the next step without further purification.
4.1.5.16. N-(b-
D-Glucopyranosylmethyl)-4-acetoxy cinnamide
(19c).
Yield 48% from 5, a white solid. mp 165–168 °C. 1H
NMR (400 MHz, DMSO-d6): d 8.10 (s, 1H, –NH–), 7.62 (d, 2H,
J = 8.0 Hz, 2-Ph0, 6-Ph0), 7.45 (d, 1H, J = 15.2 Hz, C@CH–Ph0), 7.18
(d, 2H, J = 8.0 Hz, 3-Ph0, 5-Ph0), 6.70 (d, 1H, J = 15.6 Hz, HC@CH–
Ph0), 5.09 (d, 1H, J = 4.8 Hz, 2-OH), 4.97 (d, 1H, J = 4.0 Hz, 3-OH),
4.94 (d, 1H, J = 5.2 Hz, 4-OH), 4.44 (t, 1H, J = 10.0 Hz, 6-OH), 3.80
(dd, 1H, J1 = 6.8 Hz, J2 = 12.8 Hz, H-6b), 3.69 (dd, 1H, J1 = 8.4 Hz,
J2 = 10.4 Hz, H-6a), 3.41–3.44 (m, 1H, H-5), 3.10–3.18 (m, 4H, H-
4, H-2, H-3, Glu-CH), 3.02 (t, 1H, J = 8.4 Hz, H-1), 2.91–2.96 (m,
1H, Glu-CH), 2.28 (s, 3H, –OAc). Anal. Calcd for C18H23NO8: C,
56.69; H, 6.08; N, 3.67. Found: C, 56.71; H, 6.07; N, 3.69.
4.1.9. N-(b-D-Glucopyranosylmethyl)-3,4,5-triacetoxy
benzamide (16)
The mixture of 15 (300 mg, 0.54 mmol) in AcOH/H2O (20 ml/
10 ml) was stirred at 90 °C for 1 h. Removed the solvent under re-
duced pressure and the crude product 16 was obtained which was
purified by silica-gel chromatography column eluting with
CHCl3:MeOH = 8:1 to give 16 (100 mg, 54.7%) as white solid.
mp143–145 °C. 1H NMR (400 MHz, DMSO-d6): d 8.46 (s, 1H, –
NH–), 7.71 (s, 2H, 2-Ph0, 6-Ph0), 5.08 (d, 1H, J = 5.2 Hz, 2-OH), 4.95
(d, 1H, J = 4.0 Hz, 3-OH), 4.92 (d, 1H, J = 4.8 Hz, 4-OH), 4.39 (t 1H,
J = 5.6 Hz, 6-OH), 3.84 (dd, 1H, J1 = 5.6 Hz, J2 = 12.8 Hz, H-6b),
3.66 (dd, 1H, J1 = 7.2 Hz, J2 = 11.6 Hz, H-6a), 3.39–3.44 (m, 1H, H-
5), 3.13–3.24 (m, 3H, H-2, Glu-CH, H-3), 3.08 (t, 1H, J = 9.2 Hz, H-
4), 2.92–3.03 (m, 2H, H-1, Glu-CH), 2.33 (s, 3H, 4-OAc), 2.32 (s,
6H, 3-OAc, 5-OAc). Anal. Calcd for C20H25NO12: C, 50.96; H, 5.35;
N, 2.97. Found: C, 50.99; H, 5.32; N, 2.95.
4.1.5.17. N-(b-
D-Glucopyranosylmethyl)-3-methoxy-4-hydroxy
cinnamide (19d).
Yield 54% from 5, white solid. mp
a
198–201 °C. 1H NMR (400 MHz, DMSO-d6): d 9.45 (s, 1H, –OH–
Ph0), 7.92 (s, 1H, –NH–), 7.35 (d, 1H, J = 15.2 Hz, C@CH–Ph0),
7.14 (d, 1H, J = 2.4 Hz, 6-Ph0), 6.99 (dd, 1H, J1 = 2.0 Hz,
J2 = 8.4 Hz, 2-Ph0), 6.79 (d, 1H, 8.0 Hz, 5-Ph0), 6.53 (d, 1H,
J = 15.6 Hz, HC@CH–Ph0), 5.07 (d, 1H, J = 5.2 Hz, 2-OH), 4.91–
4.95 (m, 2H, 3-OH, 4-OH), 3.67–3.72 (m, 1H, 6-OH), 4.42 (dd,
1H, J1 = 4.8 Hz, J2 = 7.6 Hz, H-6b), 3.77(dd, 1H, J1 = 7.2 Hz,
J2 = 12.4 Hz, H-6a), 3.40–3.46 (m, 1H, H-5), 3.06–3.18 (m, 4H,
H-4, H-2, H-3, Glu-CH), 2.90–3.04 (m, 2H, H-1, Glu-CH). Anal.
4.1.10. N-(b-D-Glucopyranosylmethyl)-p-toluenesulfonamide
(22)
To the solution of 5 (500 mg, 1.77 mmol) in DMF (10 ml), trieth-
ylamine (0.77 ml, 5.31 mmol) was added. Then the solution of 20
(339 mg, 1.77 mmol) in DMF was added at 0 °C slowly. The mixture
was stirred at rt. until the reaction completed. Removed the sol-
vent and H2O (20 ml) was added. The mixture was extracted with
EtOAc (30 ml ꢀ2). The organic phase was dried over Na2SO4,
filtered and concentrated to get 21 (600 mg, 70.0%) as a white
solid which was directly for the next step without further
purification.
Calcd for
C17H23NO8: C, 55.28; H, 6.28; N, 3.79. Found: C,
55.31; H, 6.26; N, 3.80.
4.1.5.18. N-(b-
D-Glucopyranosylmethyl)-3,4-diacetoxy cinna-
mide (19e).
Yield 52% from 5, a white solid. mp 160–162 °C.
1H NMR (400 MHz, DMSO-d6): d 8.10 (s, 1H, –NH–), 7.49–753 (m,
Please cite this article in press as: Bian, X.; et al. Bioorg. Med. Chem. (2013), http://dx.doi.org/10.1016/j.bmc.2013.06.002

X. Bian et al. / Bioorg. Med. Chem. xxx (2013) xxx–xxx
9
The 21 was dissolved in AcOH/H2O (10 ml/15 ml) and the mix-
ture was stirred at 90 °C for 1 h. The solvent was evaporated under
reduced pressure to give the crude product 22 (300 mg, 54.7%),
which was purified by silica-gel chromatography column eluting
with CHCl3/MeOH = 5/1 as white solid. mp 84–86 °C. 1H NMR
(400 MHz, DMSO-d6): d 7.68 (d, 2H, J = 8.0 Hz, 2-Ph0, 6-Ph0), 7.49
(dd, 1H, J1 = 3.2 Hz, J2 = 8.0 Hz, –NH–), 7.40 (d, 2H, J = 8.0 Hz, 3-
Ph0, 5-Ph0), 5.02 (d, 1H, J = 5.2 Hz, 2-OH), 4.90–4.93 (m, 2H, 3-OH,
4-OH), 4.43–4.46 (m, 1H, 6-OH), 3.64–3.59 (m, 1H, H-6b), 3.25–
3.34 (m, 2H, H-5, H-6a), 2.94–3.06 (m, 3H, H-2, Glu-CH, H-3),
2.85–2.91 (m, 1H, H-4), 2.78–2.83 (m, 1H, H-1), 2.56–2.63 (m,
1H, Glu-CH), 2.39 (s, 3H, -CH3). Anal. Calcd for C14H21NO7S: C,
48.40; H, 6.09; N, 4.03; S, 9.23. Found: C, 48.43; H, 6.10; N, 4.01;
S, 9.21.
60 min, and stopped in the boiling water bath. Then the above
solution (10 l) was added to the mixture of reagent A (500 l,
containing 10.6 mM of phenol) and reagent B (500 l: containing
of 70 mM phosphate buffer, 0.8 mM of 4-aminoantipyrine, >10 U/
ml of glucose oxidase and > 10 U/ml of peroxidase, pH 7.0), and
then reaction mixture was incubated at 37 °C for 15 min. The
l
l
l
amount of D-glucose formed was measured as the absorbance at
505 nm. The assay was performed with five different concentra-
tions around the IC50 values and in each set of experiments the as-
say was performed in triplicate and at least 2 times.
Sucrase inhibitory activities were measured by the same proce-
dure described above with using sucrose as substrate.
4.2.2. Kinetic study of rat intestinal a-glucosidase inhibition
The inhibition kinetics of compound 19e towards rat intestinal
-glucosidase was continuously measured.
4.2. Biological evaluation
a
The reaction was performed as described in Section 4.2.1.2 with
4.2.1.
a
a
-Glucosidase inhibitory activity
-glucosidase inhibitory activity of the newly synthesized
inhibitors of various concentrations. Inhibition types for the inhib-
itors were determined by double-replot of slope versus the reci-
procal of the substrate concentration. The Ki value for 19e was
determined by measuring the releasing rate of glucose from sub-
The
compounds (Table 1) were evaluated towards yeast
(from Saccharomyces cerevisiae) and rat intestinal
(maltase and sucrase).
a
a
-glucosidase
-glucosidase
strate by
a-glucosidase at varying inhibitor concentrations. Data
was plotted in Lineweaver–Burk plots (1/rate vs 1/[substrate])
(Fig. 3). It revealed that compound 19e was a competitive inhibitor
with Ki value of 4.85 lM for maltase, and 17.1 lM for sucrase.
4.2.1.1. Inhibitory activity towards yeast
a
-glucosidase. The
inhibitory activity of target compounds towards yeast
a-glucosi-
dase was determined as described in the literature24,25 with a
slight modification and was expressed as the concentration re-
Acknowledgements
quired for 50% inhibition of
a-glucosidase activity (IC50). Briefly,
a
-glucosidase from Saccharomyces cerevisiae (EC. 3.2.1.20, Sigma
This work was supported by the National Natural Science Foun-
dation of China (Grant No. 21172177).
Aldrich Chemical Co. G0660) was dissolved in phosphate buffer
(pH 6.86) at a final concentration of 10 U/ml. The enzyme solution
(10
concentrations in phosphate buffer (pH 6.86) at 37 °C for 15 min.
The reaction was started by the addition of 20 l 4-nitrophenyl
-glucopyranoside (p-NPG, final concentration 5.3 mM) and
stopped after 15 min with 50 l of 0.5 M Na2CO3. The amount of
released 4-nitrophenol from p-NPG was measured as the absor-
bance at 405 nm. The assay was performed with eight different
concentrations around the IC50 values, approximately estimated
in previous experiments. In each set of experiments the assay
was performed in triplicate and at least two times. The increased
absorbance was compared with that of the control containing
ll) preincubated with 50 ll of the target products at varying
References and notes
l
a-D
1. Wild, S.; Roglic, G.; Green, A.; Sicree, R. H. King. Diabetes Care 2004, 1047, 27.
2. Fava, S. Expert Rev. Cardiovasc. Ther. 2008, 6, 859.
3. Matteo, A. J. Diabetes Complications 2009, 23, 427.
4. Zaccardi, F.; Pitocco, D.; Ghirlanda, G. Diabetes Metab. Res. 2009, 25, 199.
5. Nalysnyk, L.; Hernandez, M. M.; Krishnarajah, G. Diabetes Obes. Metab. 2010,
12, 288.
6. Ceriello, A. Diabetes Vasc. Dis. Res. 2008, 5, 260.
7. Davidson, J. Diabetes Care 1919, 2003, 26.
8. Bonora, E. Int. J. Clin. Pract. Suppl. 2002, 129, 5.
9. Maki, K. C. Am. J. Cardiol. 2004, 93, 12.
l
10. Maki, K. C.; Carson, M. L.; Miller, M. P. Diabetes Care 2007, 1039, 30.
11. Delorme, S.; Chiasson, J. L. Curr. Opin. Pharmacol. 2005, 5, 184.
12. Henry, C. J.; Lightowler, H. J.; Newens, K. Br. J. Nutr. 2008, 99, 840.
13. Milicevic, Z.; Raz, I.; Beattie, S. D. Diabetes Care 2008, 31, S155.
14. Suzuki, Y.; Sano, M.; Hayashida, K.; Ohsawa, I.; Ohta, S.; Fukud, K. FEBS Lett.
2009, 583, 2157.
15. Pascale, R.; Carocci, A.; Catalano, A., et al Bioorg. Med. Chem. 2010, 18, 590.
16. Xiaoli, B.; Qian, W.; Changhu, K., et al Bioorg. Med. Chem. Lett. 2013, 23, 2022.
17. Brazdova, B.; Tan, N. S.; Samoshina, N. M.; Samoshin, V. V. Carbohydr. Res. 2009,
344, 311.
18. Stockle, M.; Voll, G.; Cunther, R. Org. Lett. 2002, 4, 2501.
19. Melo, E. B.; Gomesand, A. S.; Carvalho, I. Tetrahedron 2006, 62, 10277.
20. Bisht, S. S.; Fatima, S.; Tamrakar, A. K.; Rahuja, N.; Jaiswal, N.; Srivastava, A. K.;
Tripathia, R. P. Bioorg. Med. Chem. Lett. 2009, 19, 2699.
21. Worawalai, W.; Wacharasindhu, S.; Phuwapraisirisan, P. Med. Chem. Commun.
2012, 3, 1466.
50 ll of phosphate buffer in place of the test solution. IC50 values
were measured graphically by a plot of percent activity versus
log of the test compound concentration.
4.2.1.2. Inhibitory activity towards rat intestinal maltase and
sucrose.
The a-glucosidase from rats intestinal brush border
membranes were prepared according to literature method24 that
were used as the enzyme source of rat intestinal maltase and su-
crose. For maltase activity determine, maltose was used as sub-
strate. The
D-glucose produced from hydrolysis of maltose was
determined colorimetrically according to the designated method
of Glucose Test Kit (Shanghai Rongsheng Biotech Co., Ltd). The en-
22. Tao, P.; Lin, W. Chemistry 2008, 1, 68.
zyme solution 10
products at varying concentrations in phosphate buffer (pH 6.86)
at 37 °C for 15 min. Then the substrate (50 mM of maltose, 20 l)
was added, and the reaction was continued to incubate for
ll was preincubated with 50 ll of the target
23. Shinde, J.; Taldone, T.; Barletta, M. Carbohydr. Res. 2008, 343, 1278.
24. Rocha, D. R.; Santos, W. C.; Lima, E. S.; Feeerira, V. F. Carbohydr. Res. 2012, 350,
14.
l
25. Chiba, S. Biosci. Biotechnol. Biochem. 1997, 61, 1233.
Please cite this article in press as: Bian, X.; et al. Bioorg. Med. Chem. (2013), http://dx.doi.org/10.1016/j.bmc.2013.06.002