Antidiabetic activity of N-(6-substituted-1,3-benzothiazol-2-yl)benzenesulfonamides

Article abstract of DOI:10.1016/j.bmcl.2008.03.086

N-(6-Substituted-1,3-benzothiazol-2-yl)benzenesulfonamide derivatives 1-8 were synthesized and evaluated for their in vivo antidiabetic activity in a non-insulin-dependent diabetes mellitus rat model. Several compounds synthesized showed significant lower

Full text of DOI:10.1016/j.bmcl.2008.03.086

Available online at www.sciencedirect.com
Bioorganic & Medicinal Chemistry Letters 18 (2008) 2871–2877
Antidiabetic activity of N-(6-substituted-1,3-
benzothiazol-2-yl)benzenesulfonamidesq
a
b,
*
´
´
Hermenegilda Moreno-Dıaz, Rafael Villalobos-Molina,
a
c
d
Rolffy Ortiz-Andrade, Daniel Dıaz-Coutino, Jose Luis Medina-Franco,
˜
Scott P. Webster,e Margaret Binnie,e Samuel Estrada-Soto,a,b
b
c
a,b,
*
´
´
Maximiliano Ibarra-Barajas, Ismael Leon-Rivera and Gabriel Navarrete-Vazquez
aFacultad de Farmacia, Universidad Auto´noma del Estado de Morelos, Cuernavaca, Morelos 62209, Mexico
bUnidad de Biomedicina, FES Iztacala, Universidad Nacional Auto´noma de Me´xico, Tlalnepantla, Me´xico 54090, Mexico
cCentro de Investigaciones Quı´micas, Universidad Auto´noma del Estado de Morelos, Cuernavaca, Morelos 62209, Mexico
dTorrey Pines Institute for Molecular Studies, Fort Pierce, FL 34946, USA
eEndocrinology Unit, Centre for Cardiovascular Science, The Queen’s Medical Research Institute, University of Edinburgh,
Edinburgh EH16 4TJ, UK
Received 8 February 2008; revised 25 March 2008; accepted 31 March 2008
Available online 8 April 2008
Abstract—N-(6-Substituted-1,3-benzothiazol-2-yl)benzenesulfonamide derivatives 1–8 were synthesized and evaluated for their in
vivo antidiabetic activity in a non-insulin-dependent diabetes mellitus rat model. Several compounds synthesized showed significant
lowering of plasma glucose level in this model. As a possible mode of action, the compounds were in vitro evaluated as 11b-hydroxy-
steroid dehydrogenase type 1 (11b-HSD1) inhibitors. The most active compounds (3 and 4) were docked into the crystal structure of
11b-HSD1. Docking results indicate potential hydrogen bond interactions with catalytic amino acid residues.
ꢀ 2008 Elsevier Ltd. All rights reserved.
Diabetes mellitus is characterized by chronic hyperglyce-
mia and belongs to a group of metabolic disorders with
multiple etiologies. Non-insulin-dependent diabetes mel-
litus (NIDDM) is very common and may result from
insulin resistance, inadequate secretion of insulin, hepa-
tic glucose overproduction or glucose intolerance.1
heart disease, stroke, and peripheral vascular disease),
and diminished quality of life.2
The American Diabetes Association (ADA) has esti-
mated the national cost of diabetes in the USA for
2002 to be US $132 billion, increasing to US $192 billion
in 2020.2
Recent estimates from the year 2000 indicate that there
are 171 million people in the world with diabetes and
this is projected to increase to 366 million by 2030.1 Dia-
betes may eventually cause microvascular damage in key
tissues leading to conditions such as retinopathy,
nephropathy, and neuropathy. It is associated with re-
duced life expectancy, significant morbidity due to spe-
cific diabetes-related microvascular complications,
increased risk of macrovascular complications (ischemic
There is thus a growing need for effective therapies to
achieve optimal glycemic control in the management
of diabetes. Orally administered antihyperglycemic
agents (OHAs) can be used either alone or in combina-
tion with other OHAs or insulin.3 The number of avail-
able OHAs has increased significantly in the last decade,
however, current therapies to reduce plasma glucose lev-
els have inherent problems including compliance, inef-
fectiveness, and the occurrence of hypoglycemic
episodes. Accordingly, there is a need for more effective,
orally administered agents, particularly ones that nor-
malize both glucose and insulin levels.4
Keywords: Diabetes; Benzothiazole; Streptozotocin–nicotinamide
model.
q
Taken in part from the Ph.D. Thesis of Hermenegilda Moreno-Diaz.
*
Corresponding authors. Tel./fax: +52 777 3297089 (G.N.); e-mail
addresses: villalobos@campus.iztacala.unam.mx; gabriel_navarrete
@uaem.mx
Glucocorticoids (GCs) are potent functional antagonists
of insulin action, and promote gluconeogenesis in the
0960-894X/$ - see front matter ꢀ 2008 Elsevier Ltd. All rights reserved.
doi:10.1016/j.bmcl.2008.03.086

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H. Moreno-Dıaz et al. / Bioorg. Med. Chem. Lett. 18 (2008) 2871–2877
2872
liver, potentially leading to raised blood glucose concen-
trations in diabetes.5 At the tissue level the access of
active GCs to its receptors is governed by 11b-hydroxy-
steroid dehydrogenase type 1 (11b-HSD1).6 This en-
zyme, which is mainly expressed in liver and adipose
tissue, catalyzes the conversion of inactive cortisone into
the active hormone cortisol (in rodents 11-dehydrocort-
icosterone to corticosterone).7
The hybridization of both structures led to the title com-
pounds reported in this paper. The design was also
based on the biological activity predictions made by
the computer software PASSꢁ (prediction of activity
spectra for substances).14,15 This software illustrates
the predicted activity spectrum of a compound as prob-
able activity (Pa) and probable inactivity (Pi) with the
accuracy of prediction reported to be as high as 85%.16
Several lines of evidence have implicated GCs and 11b-
HSD1 activity in the etiology and/or maintenance of
NIDDM and metabolic syndrome. Consequently, it is
thought that selective inhibition of 11b-HSD1 may pro-
vide a means of treating diabetes and other aspects of
the metabolic syndrome.8
Here, we report the synthesis of N-(6-substituted-1,3-
benzothiazol-2-yl)benzenesulfonamide derivatives, their
in vitro inhibition of 11b-HSD1, and their in vivo anti-
diabetic activity in streptozotocin (STZ)–nicotinamide
induced diabetic rat model.
Compounds 1–8 were synthesized from 2-amino-6-
substituted benzothiazoles 9–12, via a coupling reaction
with arylsulfonyl chlorides 13–18, in the presence of a
catalytic amount of 4-dimethylaminopyridine and tri-
ethylamine. Title compounds were recovered with 34–
90% yields (Scheme 1, Table 1).17 Compounds were
purified by recrystallization or by column chromatogra-
phy. Compounds 4, 5, 7, and 8 showed the best yields;
they contain electron-withdrawing groups para to phe-
nyl sulfonamide group (–NO2, –Cl), while compounds
1–3 and 6 , which have electron-donating groups
(–CH3, –OCH3, and –NHCOCH3) at this position, had
the lowest yields.
In recent years considerable activity in the pharmaceuti-
cal industry has led to the discovery of several chemical
classes of 11b-HSD1 inhibitors. Many patent applica-
tions explain the intense interest in this field.9 Numerous
examples of non-steroidal inhibitors have been dis-
closed; these include thiazole based compounds (I),10
sulfonamides (II),11 adamantanyl triazoles and carbox-
amides among others (Fig. 1).8,9,12,13
Compounds I and II belong to the arylsulfonamido
(benzo)thiazoles class of 11b-HSD1 inhibitors.10,11 We
choose these scaffolds as starting point to design the
compounds prepared in this work.
The chemical structures of the synthesized compounds
were confirmed on the basis of their spectral data
(NMR and mass spectra), and their purity ascertained
by microanalysis. The elemental analysis was within
0.4% of the theoretical values.18 Physical constants of
the title compounds are shown in Table 1.
Our first consideration was to move sulfonamide moiety
and its substituents from meta to para position (see Fig.
1). The second one was to mimic compound I which had
a 2-aminothiazole skeleton.
In the nuclear magnetic resonance spectra (1H NMR; d
ppm), the signals of the respective protons of the com-
pounds were verified on the basis of their chemical
shifts, multiplicities, and coupling constants. The aro-
matic region of the H NMR spectrum contained an
ABX pattern signals ranging from d 6.94–6.99 (dd,
Cl
N
H
N
O
S
Cl
N
S
N
O
O
H
N
1
Cl
N
S
Cl
O
S
O
Jmeta = 2.2–2.6; Jortho = 8.8 Hz), 7.18–7.23 (d, Jortho
=
II
I
8.8 Hz), and 7.41–7.60 (d, Jmeta = 2.2–2.6 Hz) attribut-
able to H-5, H-4, and H-7, of the benzothiazole 6-substi-
tuted structure, respectively.
O
O
A preliminary in vitro compound screen to identify
inhibitors of human 11b-HSD1 was performed on a
selection of compounds. Inhibition of 11b-HSD1 was
N
S
S
N
H
R1
R2
determined using
a
human embryonic kidney
1-8
(HEK293) cell-based assay (Table 1).8,19 Compounds 3
and 4 were the most active derivatives of the series
and showed 38–53% inhibition at 10 lM, respectively.
Figure 1. Selected 11b-HSD1 inhibitors and drug design of N-(6-
substituted-1,3-benzothiazol-2-yl)benzenesulfonamides 1–8.
O
O
O
N
N
S
a
R2
N
H
NH2
+
Cl
S
S
R1
S
R1
O
R2
1-8
13-18
9-12
Scheme 1. Reagents and conditions: (a) 4-dimethylaminopyridine (cat.), CH2Cl2, triethylamine, 40 ꢂC.

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H. Moreno-Dıaz et al. / Bioorg. Med. Chem. Lett. 18 (2008) 2871–2877
2873
Table 1. Physicochemical data, in vitro % inhibition of human 11b-HSD1, and predictive values of biological activities calculated for derivatives 1–8
O
O
N
S
S
N
H
R1
R2
Compound R1
R2
MW Mp (ꢂC)
Unoptimized % of inhibition
yield (%) 11b-HSD1 @ 10 lM
(HEK 293 cells)
Antiobesity
effect
Antidiabetic
effect
P
P
P
P
i
a
i
a
1
2
3
4
5
6
7
8
–NO
–NO
–OCH
365
392
320
365
379
348
338
349
187.1–189.3 33.8
230.2–233.1 53.3
252.9–253.2 39.4
236.9–238.2 66.1
247.9–248.9 71.2
228.4–230.3 47.1
265.6–266.9 85.9
226.3–227.5 90.1
25.61
7.69
0.845 0.006 0.631 0.007
0.809 0.006 0.595 0.007
0.889 0.005 0.716 0.006
0.833 0.006 0.654 0.007
0.817 0.044 0.651 0.007
0.858 0.006 0.687 0.007
0.872 0.006 0.697 0.006
0.835 0.006 0.653 0.007
2
2
3
–NHCOCH
–H
–NO
3
–OCH
–OCH
37.63
53.32
15.54
16.43
27.21
11.09
3
3
2
–OCH 2CH3 –NO
–OCH 2CH3 –CH
2
3
–CH
–CH
–Cl
–NO
3
3
2
Both compounds have a methoxy group attached at po-
sition 5 of the benzothiazole ring. The remaining com-
pounds displayed low levels of inhibition, suggesting
low affinity for 11b-HSD1 or poor cellular penetration.
Thr222. An oxygen atom of the sulfonamide group
forms a hydrogen bond with the hydroxyl groups of
the catalytic residues Ser170 and Tyr183 (Figs. 2 and 3).
Before the establishment of an in vivo assay, we ob-
tained predictive values concerning biological activities
by comparing the chemical structures of the compounds
designed (1–8), with structures or substructures of more
than 46,000 well-known biologꢁically active drugs in-
cluded in the database of PASS .14–16,24 The results of
the prediction are presented as estimates of the probabil-
ity P , or improbability P , which indicates that the
In order to gain an insight into the binding mode of title
compounds, 3 and 4 were docked into the ligand-bind-
ing pocket of one subunit of human 11b-HSD1 (PDB
entry 2BEL).20 Docking was performed with the pro-
gram Genetic Optimization for Ligand Docking
(GOLD) 3.2.21 Figure 2 shows the top-ranked binding
mode predicted for 4. Figure 3 depicts the corresponding
a
i
compounds are active or inactive according PASSꢁ cal-
˚
amino acid residues at 4.5 A in a 2D interaction map
generated with the program Molecular Operating Envi-
ronment 2007.09 (MOE).22 In this binding model amino
acid residues Tyr177, Pro178, Val180, and Ile 230 form
the binding pocket for the benzothiazole ring. The bind-
ing pocket of the benzenesulfonamide moiety is formed
by the nicotinamide ring of the cofactor and amino acid
residues Ile121, Thr122, Thr124, Ser170, Tyr183, and
culations. For P values >0.7, the corresponding com-
a
pound is very likely to reveal this activity in
experiments, but in this case, the chance of the com-
pound being a close analogue of a known pharmaceuti-
cal agent is also high. For P values between 0.5 and
a
0.7, the compound is likely to reveal this activity in
experiments but the compound may exhibit less similar-
˚
Figure 2. Binding model of 4 into the binding pocket of 11b-HSD1. Cofactor and amino acid residues within 4.5 A of 4 are labeled. Hydrogen bonds
are displayed as black dashes. Figure created with the program VMD 1.8.6.23

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H. Moreno-Dıaz et al. / Bioorg. Med. Chem. Lett. 18 (2008) 2871–2877
2874
˚
Figure 3. 2D interaction map of 4 docked into the 11b-HSD1 binding pocket (amino acid residues at 4.5 A of the ligand are shown).
ity to known pharmaceutical agents. For P values
a
70
60
50
40
30
<0.5, the compound is unlikely to reveal biological ac-
tivity in experiments, but if the presence of this activity
is confirmed in experiments, the compound may be a
new biologically active chemical entity.25
ISS
3
Glibenclamide
20
Results presented in Table 1 describe two biological
activities taken from PASSꢁ software: antiobesity and
antidiabetic effects. P values estimated for antiobesity
activity were ranging between 0.80 and 0.88. These re-
sults indicated that designed compounds exhibited
chemical structures similar to known antiobesity drugs,
10
0
-10
-20
-30
-40
-50
-60
-70
-80
a
*
*
and are likely to reveal this activity. P -estimated anti-
a
*
*
diabetic activity values were determined to be ranged be-
tween 0.59 and 0.71, which also indicates that chemical
structures of compounds 1–8 exhibited levels of similar-
ity to those of known antidiabetic drugs.
-1
0
1
2
3
4
5
6
7
8
Time after administration (h)
Compounds 1–7 were evaluated for in vivo antidiabetic
activity using a STZ–nicotinamide rat model of diabe-
tes.26 Glibenclamide was taken as positive control.27
The antidiabetic activity of compounds 1–7 was deter-
Figure 4. Effect of a single 3 administration (100 mg/kg; intragastric,
n = 5) in streptozotocin–nicotinamide rat model of diabetes. ISS,
isotonic saline solution. *p < 0.05 versus ISS group.
Table 2. In vivo antidiabetic activity of compounds 1–7 at 100 mg/kg dose
Compound
Blood glucose-lowering profile (mg/dL)
% of change of glucose over control
1 h
3 h
5 h
7 h
1 h
3 h
5 h
7 h
1
ꢀ22.7 4.4**
ꢀ42.2 5.1*
18.6 5.2
ꢀ27.0 8.0*
ꢀ11.9 7.1
ꢀ39.4 8.1*
ꢀ26.0 10.0
ꢀ59.6 7.8*
ꢀ32.9 5.0*
ꢀ20.1 11.2
ꢀ59.4 10.1*
ꢀ7.9 5.2
ꢀ32.4 7.7*
ꢀ33.4 4.3*
ꢀ56.6 4.5*
ꢀ31.2 10.1*
ꢀ26.4 6.5*
ꢀ35.0 6.6*
ꢀ24.8 9.6
ꢀ58.8 11.1*
ꢀ3.4 7.9
77.1**
37.2
78.1**
69.7
54.6
81.6**
34
49
19.1
4
29
30
2
17.2 6.8*
11.8
62.9
42.5
48.8
39.7
36.1
32.6
0
3
ꢀ23.7 2.3**
ꢀ15.3 5.2**
ꢀ0.2 11.7**
ꢀ27.2 9.0**
20.4 5.0*
ꢀ55.8 6.2*
ꢀ35.7 5.5*
ꢀ42.0 8.8*
ꢀ20.7 10.5*
ꢀ29.3 7.5*
ꢀ24.8 5.6*
6.8 5.5
31.5
18.1
51.7
25
53.2
27.8
23
4
5
6
31.6
21.4
55.4
0
7
12.2
51.5
0
Glibenclamide
ISS (Control)
ꢀ23.6 9.2**
78
0
54.4 9.3
Values represent means SEM. (n = 5). *p < 0.05; **p < 0.01 as compared to untreated group.
The negative value (ꢀ) indicates a decrease in glycemia compared with time 0.
ISS, isotonic saline solution.

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H. Moreno-Dıaz et al. / Bioorg. Med. Chem. Lett. 18 (2008) 2871–2877
2875
Table 3. Rule of five properties calculated for 1– 8
2
TPSA (A )
3
Volume (A )
˚
˚
Compound
MW
milogP
H bond donors
H bond acceptors
Violations
Rule
<500
365
392
320
365
379
348
338
349
<5
<5
1
<10
8
<140
114.11
<1
0
1
2
3
4
5
6
7
8
3.62 0.94
2.67 0.94
3.29 0.92
3.49 0.93
4.02 0.93
4.28 0.92
4.69. 0.66
4.03. 0.63
278.71
301.11
255.37
278.71
295.51
288.74
259.93
269.72
2
9
133.983
68.295
0
1
5
0
1
8
114.119
114.119
68.295
0
1
8
0
1
5
0
1
4
59.061
104.885
0
1
7
0
mined at 100 mg/kg dose. Among the seven screened
compounds, six of them (1, 3–7) demonstrated good glu-
cose-lowering activity ranging from 40 to 60 mg/dL in
this model of NIDDM (Table 2).28
analogues (Table 3). Their advantages include: (i) phys-
ical properties known to be compatible with desirable
pharmacokinetic (low molecular weight, favorable
ClogP, favorable hydrogen bond-donating and accept-
ing capabilities), (ii) simple synthetic access and thus
low production costs, and (iii) polar groups improving
the likelihood of reasonable solubility.
The most pronounced effect was observed during the
first hour of post-intragastric administration of tested
compounds. The percentage of variation of glucose in-
creased from 34% to 81%, compared with untreated
animals.
In conclusion, a series of N-(6-substituted-1,3-ben-
zothiazol-2-yl)benzenesulfonamides were synthesized
through a short synthetic route. Compounds 3 and 4
showed moderate inhibitory activity of 11b-HSD1 in
an in vitro cell-based assay. Docking calculations sug-
gest that these compounds may form hydrogen-bonding
interactions with the catalytic residues of 11b-HSD1.
We also demonstrated that most of the title compounds
showed good in vivo antidiabetic activity in a model of
NIDDM and have the potential to be developed further.
The study has also shown an increased probability of
compounds to be biologically active if they are selected
on the basis of PASS prediction. The high bioactivity of
compounds 3, 4, and 6 makes them a suitable lead to de-
velop new chemical entities for potential use in the treat-
ment of NIDDM.
The antidiabetic activity of the screened compounds re-
vealed that unsubstituted position 4 of the benzenesul-
fonamide (compound 3) reduced elevated blood sugar
levels in the range of 32–78%. The effect was consistent
during the seven hours of experiment (Fig. 4). Com-
pound 3, the most active derivative, showed sugar-low-
ering activity profile comparable to standard drug
glibenclamide (78% of change of glucose over control).
Compound 6, with a methyl group attached to the posi-
tion 4 of benzenesulfonamide, also showed a good su-
gar-lowering profile (25–81%). Substitution at para
position with nitro group (compound 4) showed moder-
ate changes of glucose levels compared with control,
ranging from 18% to 69%, while compound 2, with p-
acetamide group resulted in either reduction or a com-
plete loss of antihyperglycemic activity. Noteworthy, 2
showed the lowest percentage of inhibition of 11b-
HSD1 (Table 1).
Acknowledgments
´
G. Navarrete-Vazquez wishes to thank the postdoctoral
fellowship given by DGAPA-UNAM, and Facultad de
Farmacia, UAEM. H. Moreno-Diaz acknowledges the
fellowship awarded by CONACyT to carry out graduate
studies. J.L. Medina-Franco is grateful to the State of
Florida, Executive Office of the Governor’s Office of
Tourism, Trade, and Economic Development. This
work was supported in part by grants from CONACYT,
project 55591, given to G. Navarrete Vazquez, PAPCA
(FESI-UNAM), and PAPIIT IN203205 (DGAPA-
UNAM), given to R. Villalobos-Molina.
Interestingly, a good agreement was found between pre-
dicted probabilities (P ) of antiobesity and antidiabetic
a
effect, and experimental in vivo antidiabetic activities.
The predicted probabilities showed the following rank
order: 3 > 7 > 6 > 4 > 8 > 5 > 1 > 2 (Table 1). Com-
pound 3, with the highest value of P a, was the most ac-
tive in the in vivo antidiabetic effect, while compound 2,
with the lowest value of P was practically inactive in
a
the in vivo model.
The benzothiazoles prepared in this work have physical
properties compatible with reasonable pharmacokinetics
and drug availability. It is important to note that com-
pounds 3 and 6 (the in vivo most active compounds)
possess the same total polar surface area
References and notes
1. Wild, S.; Roglic, G.; Green, A.; Sicree, R.; King, H.
Diabetes Care 2004, 27, 1047.
2. Hogan, P.; Dall, T.; Nikolov, P. Diabetes Care 2003, 26,
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3. Krentz, A.; Bailey, C. Drugs 2005, 65, 385.
4. Sarabu, R.; Tilley, J. Ann. Rep. Med. Chem. 2005, 40, 167.
2
˚
(TPSA = 68.295 A ), while inactive compound 2, has a
2
TPSA value of 133.983 A . These compounds are fully
˚
compatible with Lipinski’s rule of five,29 which should
allow for the development of additional antidiabetic

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H. Moreno-Dıaz et al. / Bioorg. Med. Chem. Lett. 18 (2008) 2871–2877
2876
5. Alberts, P.; Engblom, L.; Edling, N.; Forsgren, M.;
7.84 (d, 2H, H-4, H-5, J = 8.8), 8.52 (s, 1H, NH), 8.69 (s,
4H, H-20, H-30, H-50, H-60), 9.11 (s, 1H, H-7) ppm. 13C
NMR (50.28 MHz, DMSO-d6): d 23.91 (CH3), 116.87 (C-
7),116.93 (C-5), 117.71 (C-30, C-50), 118.02 (C-4), 121.91
(C-7a), 122.03 (C-20, C-60), 131.56 (C-10), 140.67 (C-40),
153.64 (C-6), 158.54 (C-3a), 163.31 (CO), 171.75 (C-2)
ppm; MS(FAB+): m/z 393 (M+H)+; Anal. Calcd for
C15H12N4O5S2: C, 45.91; H, 3.08; N, 14.28. Found: C,
45.91; H, 3.08; N, 14.28.
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N-(6-Methoxy-1,3-benzothiazol-2-yl)benzenesulfonamide
1
(3). White solid. Mp 252.9–253.2 ꢂC H NMR (200 MHz,
DMSO-d6): d 6.97 (dd, 1H, H-5, J = 8.8, J = 2.2 Hz), 7.20
(d, 1H, H-4, J = 8.8 Hz), 7.45(d, 1H, H-7, J = 2.2 Hz),
7.61–7.44 (m, 3H, H-0, H-40, H-50), 7.84 (m, 2H, H-20, H-
60) ppm. 13C NMR (50.28 MHz, DMSO-d6): d 55.71
(CH3O), 106.90 (C-7), 113.42 (C-5), 114.61 (C-4), 125.62
(C-20, C-60), 125.90 (C-7a), 129.12 (C-30, C-50), 129.70 (C-
40), 132.21 (C-10), 142.03 (C-4a), 155.92 (C-6), 166.40 (C-
2). MS (FAB+): m/z 321 (M+H)+; Anal. Calcd for
C14H12N2O3S2: C, 52.48; H, 3.78; N, 8.74. Found: C,
52.29; H, 3.65; N, 8.98.
11. Su, X.; Vicker, N.; Ganeshapillai, D.; Smith, A.; Purohit,
A.; Reed, M. J.; Potter, B. V. Mol. Cell Endocrinol. 2006,
248, 214.
N-(6-Methoxy-1,3-benzothiazol-2-yl)-4-nitrobenzenesulf-
1
onamide (4). Yellow solid. Mp 236.9–238.2 ꢂC. H NMR
12. Olson, S.; Aster, S. D.; Brown, K.; Carbin, L.; Graham,
D. W.; Hermanowski-Vosatka, A.; LeGrand, C. B.;
Mundt, S. S.; Robbins, M. A.; Schaeffer, J. M.; Slossberg,
L. H.; Szymonifka, M. J.; Thieringer, R.; Wright, S. D.;
Balkovec, J. M. Bioorg. Med. Chem. Lett. 2005, 15, 4359.
13. Boyle, C. D.; Kowalski, T. J.; Zhang, L. . L. Ann. Rep.
Med. Chem. 2006, 41, 127.
14. Stepanchikova, A. V.; Lagunin, A. A.; Filimonov, D. A.;
Poroikov, V. V. Curr. Med. Chem. 2003, 10, 225.
15. Poroikov, V. V.; Filimonov, D. A.; Borodina, Y. V.;
Lagunin, A. A.; Kos, A. . J. Chem. Inf. Comput. Sci. 2000,
40, 1349.
(200 MHz, DMSO-d6): d 3.79 (s, 3H, CH3O), 6.99 (dd,
1H, H-5 J = 8.8, J = 2.2 Hz), 7.23 (d, 1H, H-4,
J = 8.8 Hz), 7.47 (d, 1H, H-7, J = 2.2 Hz), 8.08 (d, 2H,
H-20, H-60, J = 8.4 Hz), 8.36 (d, 2H, H-30, H-50,
J = 8.8 Hz) ppm; 13C NMR (50.28 MHz, DMSO-d6) d
55.71 (CH3), 106.90 (C-7), 113.81 (C-5), 114.92 (C-4),
124.40 (C-30, C-50), 126.04 (C-7a), 127.21 (C-20, C-60),
129.70 (C-3a), 147.30 (C-10), 149.32 (C-40), 156.21 (C-6),
167.02 (C-2) ppm; MS (FAB+): m/z 366 (M+H)+; Anal.
Calcd for C14H11N3O5S2: C, 46.02; H, 3.03; N, 11.50.
Found: C, 45.75; H, 2.93; N, 11.77.
N-(6-Ethoxy-1,3-benzothiazol-2-yl)-4-nitrobenzenesulf-
1
16. Poroikov, V. V.; Filimonov, D. A. J. Comput. Aided Mol.
Des. 2002, 16, 819.
17. General method of synthesis of derivatives 1–8 . To a
onamide (5). Yellow solid. Mp 247.9–248.9 ꢂC. H NMR
(200 MHz, DMSO-d6): d 1.31 (t, 3H, CH3), 4.01 (q, 2H,
CH2O), 6.99 (dd, 1H, H-5, J = 8.8, J = 2.6 Hz), 7.23 (d,
1H, H-4, J = 8.8 Hz), 7.47 (d, 1H, H-7, J = 2.2 Hz), 8.11–
8.05 (m, 2H, H-20, H-60), 8.39–8.33 (m, 2H, H-30, H-50)
ppm; 13C NMR (50.28 MHz, DMSO-d6) d 14.26 (CH3),
63.42 (CH2O), 107.18 (C-4), 113.46 (C-7), 124.13 (C-30, C-
50), 126.86 (C-20, C-60), 129.30 (C-5), 147.03 (C-7a), 148.9
(C-6), 155.08 (C-10), 166.66 (C-40), 171.93 (C-3a), 172.80
(C-2) ppm; MS (FAB+): m/z 380 (M+H)+; Anal. Calcd for
C15H13N3O5S2: C, 47.48; H, 3.45; N, 11.08. Found: C,
46.88; H, 3.33; N, 11.26.
solution
of
2-amino-6-substituted
benzothiazole
(0.0030 mol) in dichloromethane (10 mL) were added
triethylamine (1.1 equiv), and a catalytic amount of 4-
dimethylaminopyridine (DMAP). After stirring at room
temperature for 15 min, a solution of 4-substituted-
benzenesulfonyl chloride (0.0033 mol, 1.1 equiv) in 5 mL
of dichloromethane was added droopingly. The reaction
mixture was stirred at 40 ꢂC under nitrogen atmosphere
for 6–10 h. After complete conversion as indicated by
TLC, the solvent was removed in vacuo, the residue was
neutralized with saturated NaHCO3 solution, and the
aqueous layer was extracted with ethyl acetate (3· 15
mL), washed with water (3· 20 mL), and dried over
anhydrous Na2SO4. The solvent was evaporated in vacuo
and the precipitated solids were recrystallized from an
appropriate solvent or purified by column chromatography.
18. 4-Methoxy-N-(6-nitro-1,3-benzothiazol-2-yl)benzene sul-
fonamide (1). Yellow solid. Mp 187.1–189.3 ꢂC. 1H
NMR (200 MHz, DMSO-d6): d 3.80 (s, 3H, CH3O), 7.08
(d, 2H, H-30, H-50, J = 8.0), 7.80 (d, 2H, H20, H60,
J = 8.4), 8.21 (sa, 2H, H-4, H-5), 8.81 (s, 1H, H-7) ppm.
13C NMR (50.28 MHz, DMSO-d6): d 55.65 (CH3), 114.27
(C-30, C-50), 119.15 (C-7), 123.15 (C-5), 126.30 (C-4),
126.97 (C-7a), 127.99 (C-20, C-60), 133.12 (C-10), 138.96
(C-6), 142.81 (C-3a), 162.28 (C-40), 167.75 (C-2) ppm; MS
(FAB+): m/z 366 (M+H)+; Anal. Calcd for C14H11N3O5S2:
C, 46.02; H, 3.03; N, 11.50. Found: C, 46.49; H, 3.83; N,
10.94.
N-(6-Ethoxy-1,3-benzothiazol-2-yl)-4-methylbenzene sul-
1
fonamide (6). Beige solid. Mp 228.4–230.3 ꢂC. H NMR
(200 MHz, DMSO-d6): d 1.30 (t, 3H, CH3), 2.33 (s, 3H,
CH3O), 3.99 (q, 2H, CH2O), 6.94 (dd, 1H, H-5, J = 8.8,
J = 2.6 Hz), 7.18 (d, 1H, H-4, J = 8.8 Hz), 7.34 (d, 2H, H-
30, H-50, J = 8.0 Hz), 7.41 (d, 1H, H-7, J = 2.6 Hz), 7.73
(d, 2H, H-30, H-70, J = 8.2 Hz) ppm; 13C NMR
(50.28 MHz, DMSO-d6) d 14.26 (CH3), 20.63 (CH3),
63.34 (CH2), 107.10 (C-7), 113.07 (C-4), 114.60 (C-7a),
125.32 (C-20, C-60), 125.53 (C-5), 129.02 (C-30, C-50),
130.02 (C-6), 138.80 (C-10), 142.04 (C-40), 154.70 (C-3a),
165.80 (C-2) ppm. MS(FAB +): m/z 349 (M+H)+; Anal.
Calcd for C16H16N2O3S2: C, 55.15; H, 4.63; N, 8.04.
Found: C, 54.20; H, 4.40; N, 8.04.
4-Chloro-N-(6-methyl-1,3-benzothiazol-2-yl)benzenesul-
1
fonamide (7). White solid. Mp 265.6–266.9 ꢂC. H NMR
(200 MHz, DMSO-d6): d 7.19 (s, 1H, H-7), 7.61 (m, 4H,
H-20, H-30, H-50, H-60), 7.86 (m, 2H, H-4, H-5) ppm. 13C
NMR (50.28 MHz, DMSO-d6): d 20.75 (CH3), 112.54 (C-
7), 122.42 (C-4), 124.69 (C-7a), 127.65 (C-20, C-60), 128.13
(C-5), 129.14 (C-30, C-50), 133.25 (C-6), 133.85 (C-40),
137.04 (C-3a), 140.80 (C-10), 166.91 (C-2) ppm. MS
N-(4-{[(6-Nitro-1,3-benzothiazol-2-yl)amino]sulfonyl}
phenyl)acetamide (2). Yellow solid. Mp 230.2–233.1 ꢂC.
1H NMR (200 MHz, DMSO-d6): d 2.94 (s, 3H, CH3CO),

´
H. Moreno-Dıaz et al. / Bioorg. Med. Chem. Lett. 18 (2008) 2871–2877
2877
(FAB+): m/z 339 (M+H)+; Anal. Calcd for
C14H11ClN2O2S2: C, 49.63; H, 3.27; N, 8.27. Found: C,
49.02; H, 3.13; N, 8.26.
23. Humphrey, W.; Dalke, A.; Schulten, K. J. Mol. Graphics
1996, 14, 33.
24. Website: http://www.ibmh.msk.su/PASS.
25. Marwaha, A.; Goelb, R. K.; Mahajana, M. P. Bioorg.
Med. Chem. Lett. 2007, 17, 5251.
26. Masiello, P.; Broca, C.; Gross, R.; Roye, M.; Manteghetti,
M.; Hillaire-Buys, D.; Novelli, M.; Ribes, G. Diabetes
1998, 47, 224.
N-(6-methyl-1,3-benzothiazol-2-yl)-4-nitrobenzenesulf-
onamide (8). Beige solid. Mp 226.3–227.5 ꢂC. 1H NMR
(200 MHz, DMSO-d6): d 2.3 (s, 3H, CH3), 7.19 (s, 2H, H-
4, H-5), 7.60 (s, 1H, H-7), 8.07 (d, 2H, H-20, H-60,
J = 8.8 Hz), 8.34 (d, 2H, H-30, H-50, J = 8.8 Hz) ppm. 13C
NMR (50.28 MHz, DMSO-d6): d 20.73 (CH3), 112.80 (C-
7), 122.44 (C-4), 124.40 (C-30, C-50), 124.92 (C-7a), 127.20
(C-20, C-60), 128.20 (C-5), 133.43 (C-6), 134.15 (C-10),
147.30 (C-3a), 149.30 (C-40), 167.30 (C-2) ppm; MS
(FAB+): m/z 350 (M+H)+; Anal. Calcd for C14H11N3O4S2:
C, 48.13; H, 3.17; N, 12.03. Found: C, 47.38; H, 3.13; N,
12.16.
´
27. Ortiz-Andrade, R. R.; Rodrıguez-Lopez, V.; Gardun˜o-
Ramırez, M. L.; Castillo-Espan˜a, P.; Estrada-Soto, S. J.
´
´
Ethnopharmacol. 2005, 101, 37.
28. In vivo antidiabetic assay. Induction of diabetes:
streptozotocin (STZ) was dissolved in citrate buffer
(pH 4.5) and nicotinamide was dissolved in normal
physiological saline. NIDDM was induced in overnight
19. In vitro inhibition 11b-HSD1 assay. In vitro cellular
enzyme inhibition was determined using a scintillation
proximity assay (SPA).8 Human 11b-HSD1 enzyme inhi-
bition was assessed in HEK293 cells stably transfected
with the full-length human hsd11b1 gene. HEK293 cells
were plated in 96-well poly-D-Lys coated flat-bottomed
microplates in DMEM containing 1% glutamine, 1%
penicillin and streptomycin. Compounds 1–8 were added
to plates such that the final concentration of DMSO was
1%. Tritiated cortisone was added at a final concentration
of 20 nM and the cells incubated at 37 ꢂC in 5% CO2, 95%
O2 for 2 h. The assay solutions were transferred to a
scintillation microplate and mixed with a solution of
antimouse YSi SPA beads and anticortisol antibody in
assay buffer (50 mM Tris–HCl, pH 7.0; 300 mM NaCl,
1 mM EDTA, 5% glycerol). The plate was incubated for
2 h at room temperature and read on a scintillation
counter. The percentage of inhibition was determined
relative to a non-inhibited control.
20. Berman, H. M.; Westbrook, J.; Feng, Z.; Gilliland, G.;
Bhat, T. N.; Weissig, H.; Shindyalov, I. N.; Bourne, P. E.
Nucleic Acids Res. 2000, 28, 235, Website: http://
www.rcsb.org/pdb/home/home.do.
21. Jones, G.; Willett, P.; Glen, R. C.; Leach, A. R.; Taylor,
R. J. Mol. Biol. 1997, 267, 727.
22. Chemical Computing Group Inc., 1255 University
Street, Montreal, Quebec, Canada H3B 3X3, 2005.
Molecular Operating Environment (MOE). http://www.
chemcomp.com.
fasted rats by a single intraperitoneal injection of
65 mg/kg streptozotocin, 15 min after the i.p adminis-
tration of 110 mg/kg of nicotinamide. Hyperglycemia
was confirmed by the elevated glucose levels in plasma,
determined at 72 h by glucometer. The animals with
blood glucose concentration higher 250 mg/dL, were
used for the antidiabetic screening.The diabetic animals
were divided into groups of five animals each (n = 5).
Rats of experimental groups were administered
a
suspension of the compounds 1– 7 (prepared in 1%
Tween 80) orally (100 mg/kg body weight). Control
group animals were also fed with 1% Tween 80.
Glibenclamide (5 mg/kg) was used as hypoglycemic
reference drug. Blood samples were collected from the
caudal vein at 0, 1, 3, 5, and 7 h after vehicle, sample,
and drug administration. Blood glucose concentration
was estimated by enzymatic glucose oxidase method
using
a
commercial glucometer (Accutrend GCT,
Rocheꢁ). The percentage variation of glycemia for each
group was calculated in relation to initial (0 h) level,
according to: % Variation of glycemia=[(G x
ꢀ
G0)/G
0] · 100, where G0 were initial glycemia values and Gx
were the glycemia values at +1, +3, +5, and +7 h,
respectively. All values were expressed as means
SEM. Statistical significance was estimated by analy-
sis of variance (ANOVA), p < 0.05 and p < 0.01 implies
significance.
29. Lipinski, C. A.; Lombardo, F.; Dominy, B. W.; Feeney, P.
J. Adv. Drug Delivery Rev. 1997, 23, 3.