International Journal of Pharmacy and Pharmaceutical Sciences, Vol. 1, Issue 1, July-Sep. 2009
Research article
SYNTHESIS AND PHARMACOLOGICAL EVALUATION OF SOME NOVEL
POTENT TYPE II ANTIDIABETIC AGENTS.
VELINGKAR VS*, DANDEKAR VD, MURUGANANTHAN K.
*E mail- [email protected]/ [email protected], Tel: +91-02222164387/22164368
Department of Pharmaceutical Chemistry, K.M.Kundnani College of Pharmacy- Cuffe Parade, Mumbai-4000005
Received- 07 March 09, Revised and Accepted- 30 March 09
ABSTRACT
Diabetes mellitus constitutes a major health problem in modern societies. A major role of
antidiabetic therapy is to restrict blood glucose control, which approximates normal
fasting levels and normal elevations of postprandial blood glucose. Sulfonylureas are the
mainstay of antidiabetic therapy for many years.
The present work involves the synthesis of the lead molecule N-[4-{2-(5-chloro-2methoxy
benzamido)
ethyl}phenyl
sulfonyl]-N’-cyclohexyl
urea
known
as
Glibenclamide, second generation sulfonylurea and its novel analogs. The synthesized
compounds were screened for antidiabetic activity .The structures of title compounds
were established by elemental and spectral analysis.
Keywords : Sulfonylureas, Glibenclamide analogs, Hypoglycemia.
INTRODUCTION
Sulfonylureas are the mainstay of
Type II diabetes is a debilitating disease
antidiabetic therapy for many years.
that arise from improper energy storage
Several structurally modified agents,
and utilization. The global prevalence of
which have been added in Sulfonylurea
type II diabetes, which is presently
class, still there is need of efficacious
estimated to affect more than 100
agents, which are sufficiently nontoxic
million people, is set to double by the
for chronic use2,3.
year
20101.
and
The present work describes the synthesis
show
(scheme 1) and antidiabetic evaluation
increasing prevalence of diabetes with
of novel analogs of Glibenclamide,
time. Hence, there is a crying need to
second-generation Sulfonylurea.
synthesize more effective and oral
The various substituted carboxylic acids
antidiabetic agents.
namely,
epidemiological
Statistical
data
data
clearly
5-chloro-2-methoxy
benzoic
acid, 2-methoxy benzoic acid, benzoic
149
acid, 5-chloro-2-hydroxy benzoic acid,
taken as reference standard. It was
chloro acetic acid were refluxed with
obtained from U.S.Vitamins (India),
thionyl chloride to give corresponding
Mumbai as gift sample. Blood glucose
acid chlorides. The individual acid
strips (Haemoglucotest 20-800R) and
chlorides were further treated with 2-
blood
phenethylamine in presence of base to
Boehringer Mannhein,India were used
produce corresponding amides. The
to estimate the blood glucose level.
corresponding sulfonamide derivatives
Synthesis of 5-chloro-2-methoxy-benzoyl
were prepared by chlorosulfonation and
chloride4.
amidation of theses prepared amides.
5-chloro-2-methoxy benzoic acid (0.13
Finally,
mol), 75 ml of freshly distilled thionyl
obtained
the title compounds
by
reacting
were
sulfonamide
glucometer
chloride
and
a
Obtained
drop
from
of dimethyl
derivatives with isocyanates.
formamide (DMF) were refluxed in a
EXPERIMENTAL
boiling water bath for 2hrs. The final
Melting
points
of
the
synthesized
product was purified by distillation
molecules were determined by open
under reduced pressure.
capillary tube and were uncorrected. The
The
purity of the compounds was ascertained
synthesized from benzoic acid, 2-
by thin layer chromatography (TLC) on
methoxy
pre-coated silica gel G plate. I.R. spectra
hydroxy benzoic acid, chloro acetic acid
were recorded on Jasco FT/IR-5300
using the same thionyl chloride method
spectrometer using KBr pellet method.
as described above.
Nuclear magnetic resonance spectra
Synthesis of 5-chloro-2-methoxy-N-(2-
were recorded using Bruker 200.13
phenethyl) benzamide5.
MHz spectrometer. Elemental analysis
5-chloro-2-methoxy-benzoyl
was performed using Dumas method.
(0.055 mol) was added in small portions
The pharmacological evaluation was
to a solution of 2-phenethylamine (0.11
conducted at K.M.Kundnani college of
mol) and 120 ml of 10% potassium
pharmacy,Mumbai,
hydroxide with constant shaking and
clearance
from
after
obtaining
institutional
animal
ethics committee. Glibenclamide was
various
acid
benzoic
intermittent
chlorides
acid,
cooling.
The
were
5-chloro-2-
chloride
separated
white solid was then filtered at the pump
150
and washed thoroughly with water. It
Synthesis of 4-[(5-chloro-2-methoxy
was
benzamido) ethyl] benzene sulfonamide.
then
triturated
with
saturated
solution of sodium bicarbonate to
4-[(5-chloro-2-methoxy
remove the traces of acid. The crude
ethyl]
product was filtered, washed with
(0.011mol) was suspended in 80ml of
water and then recrystallized using
25% ammonium hydroxide and the
chloroform.
mixture was stirred at room temperature
The various substituted amides were
for 5 hr. The mixture was diluted with
prepared by similar procedure.
100 ml of water and 20ml of chloroform
Synthesis of 4-[(5-chloro-2-methoxy
to yield crude product. The crude
benzamido) ethyl] benzene sulfonyl
product was filtered, washed with water
chloride6.
and then recrystallized from ethanol.
Chlorosulphonic acid (0.16 mol) was
The substituted sulfonamides were
added dropwise to a cooled and stirred
synthesized by similar procedure as
solution of 5-chloro-2-methoxy-N-(2-
described above.
phenethyl) benzamide (0.02 mol) in 100
Synthesis
ml chloroform. The reaction mixture
methoxy
was taken in a stoppered flask and
sulfonyl]-N’-cyclohexyl urea7,8.
stirring was continued for 4 hr at room
To a solution of 4-[(5-chloro-2-methoxy
temperature and then the mixture was
benzamido) ethyl] benzene sulfonamide
poured into one liter of ice-cold water.
in 8ml of 10% sodium hydroxide and
The organic layer was separated and the
20ml
aqueous layer extracted with chloroform.
cyclohexylisocyanate
The combined organic layer was dried
dropwise and the mixture was kept aside
over
the
for 3 hr. It was then diluted with water:
organic solvent was evaporated. On
methanol mixture (1:1), filtered and
standing 4-[(5-chloro-2-methoxy benzamido)
acidified with HCl. The separated solid
ethyl]
was
magnesium
benzene
sulphate
sulfonyl
and
chloride
benzene
of
sulfonyl
chloride
N-[4-{2-(5-chloro-2-
benzamido)
acetone
further
benzamido)
treated
ethyl}phenyl
at
0-5ºC,
was
added
with
sodium
solidified. The other substituted sulfonyl
methoxide and the salt obtained was
chlorides were synthesized in similar
recrystallized from acetic acid to yield
manner.
pure title compound.
151
O
O
R
C
DMF
OH + SOCl2
0
Substituted
thionyl chloride
carboxylic acids
75-78 C
R
Cl
C
Substituted acid chlorides
CH2 CH2 NH2
KOH
2-Phenethylamine
O
CH2
CH2
NH
C
R
Substituted amides
0
0-5 C
CHCl3 , chlorosulfonic acid
O
ClSO2
CH2
CH2
NH
C
R
Substituted sulfonyl chlorides
25% ammonium hydroxide NH3
O
NH2SO
CH2
CH2
NH
C
R
Substituted sulfonamides
N
R1
C O 10% sodium hydroxide , acetone
substituted isocyanates
0
0-5 C
O
R1NH
C
NHSO2
CH2 CH2 NH
C
R
O
Title compounds (1-10)
Scheme 1
152
Compound no.
Cl
R1
R
1
OMe
Cl
2
CH3
OMe
Cl
3
OH
Cl
CH3
4
OH
5
OMe
CH3
6
OMe
7
CH3
8
9
CH2Cl
10
CH2Cl
CH3
N-[4-{2-(5-chloro-2-methoxy benzamido)
8.56(obs.); 1NMR (CDCl3, (ppm):7.10-
ethyl}phenyl
7.90 (m, 7H,aromatic), 3.40 (s,3H,OCH3),
sulfonyl]-N’-cyclohexyl
urea (1)
2.64(t,2H,R-CH2-Ar),
IR(KBr;cm-1):3032 (C-H stretching -
CONH), 1.44(m, 6H,cyclohexane).
Ar), 756(C-H bending-Ar), 2932 (C-H
N-[4-{2-(5-chloro-2-methoxy benzamido) ethyl}
stretching-Aliphatic),
phenyl sulfonyl]-N’-methyl urea (2)
1718
(carbonyl
5.84(s,
1H,
-
stretching), 3368 (NH stretching amide),
IR(KBr;cm-1): 2988 (C-H stretching -
1618 (NH bending amide), 1157 (S=O
Ar), 771(C-H bending-Ar), 2854 (C-H
stretching),
stretching-Aliphatic),
nitrogen
883
analysis
(C-Cl
8.52
stretching);
(calc.),
1715
(carbonyl
stretching), 3398 (NH stretching amide),
153
1523(NH bending amide), 1154 (S=O
N-[4-{2-(2-methoxy benzamido) ethyl}
stretching),
phenyl sulfonyl]-N’-cyclohexyl urea (5)
864
(C-Cl
stretching);
nitrogen analysis 9.88 (calc.), 9.80
IR (KBr; cm-1): 3053 (C-H stretching -
(obs.); 1NMR (CDCl3,
(ppm): 7.24-
Ar), 758(C-H bending Ar), 2953(C-H
7.88(m, 7H,aromatic), 3.34 (s,3H,OCH3),
stretching aliphatic), 1622 (carbonyl
2.58 (t,2H,R-CH2-Ar), 6.18 (s, 1H, -CONH).
stretching) 3369 (N-H stretching amide),
N-[4-{2-(5-chloro-2-hydroxy benzamido)
1595 (N-H bending amide), 1155,1319
ethyl}phenyl
(S=O stretching); nitrogen analysis 9.15
sulfonyl]-N’-cyclohexyl
urea (3)
(calc.), 9.18 (obs.);
-1
IR(KBr;cm ): 3092 (C-H stretching -
(ppm):
7.10-7.68
1
NMR (CDCl3,
(m,8H,aromatic),
Ar), 788(C-H bending-Ar), 2852 (C-H
3.28(s,3H,OCH3),
stretching-Aliphatic),
(carbonyl
Ar), 6.28 (s,1H,-CONH),1.42 (m, 6H,
stretching
cyclohexane).
stretching),
3364
1682
(N-H
2.62
(t,2H,R-CH2-
amide), 1610 (N-H bending amide),
N-[4-{2-(2-methoxy benzamido) ethyl}
1153,1325 (S=O stretching), 827 (C-Cl
phenyl sulfonyl]-N’-methyl urea (6)
stretching);
8.77
IR (KBr;cm-1): 2932 (C-H stretching -
NMR (CDCl3,
Ar), 758(C-H bending-Ar), 2854 (C-H
nitrogen
(calc.), 8.67 (obs.);
analysis
1
(ppm): 6.90-7.40 (m,7H,aromatic), 4.54
stretching-Aliphatic),
1620
(carbonyl
(s,1H,Ar-OH),2.60(t,2H,R-CH2-Ar),
stretching), 3369 (NH stretching amide),
5.90(s, 1H, -CONH), 1.30(m, 6H,
1521 (NH bending amide), 1152 (S=O
cyclohexane).
stretching); nitrogen
N-[4-{2-(5-chloro-2-hydroxy benzamido)
(calc.), 10.83 (obs.); 1NMR (CDCl3,
ethyl}phenyl sulfonyl]-N’-methyl urea (4)
(ppm): 6.98-7.62 (m,8H,aromatic), 3.42
IR(KBr;cm-1): 3090 (C-H stretching -
(s,3H,OCH3),
Ar), 790 (C-H bending-Ar), 2866 (C-H
5.38 (s, 1H, -CONH).
stretching-Aliphatic),
N-[4-{2-(benzamido)
1685
(carbonyl
2.64
analysis
10.74
(t,2H,R-CH2-Ar),
ethyl}
phenyl
stretching), 3394 (NH stretching amide),
sulfonyl]-N’-cyclohexyl urea (7)
1525 (NH bending amide), 1153 (S=O
IR (KBr; cm-1): 3082 (C-H stretching -
stretching), 827(C-Cl stretching; nitrogen
Ar),
analysis 10.22 (calc.), 10.21 (obs.);
(carbonyl
1
stretching amide), 1574 (NH bending
NMR
(CDCl3,
(ppm):6.84-7.40
771
(C-H
bending-Ar),
stretching),
3393
1630
(NH
(m,7H,aromatic),
amide), 1157, 1309 (S=O stretching);
4.54(s,1H,ArOH),2.54(t,2H,R-CH2-Ar),
nitrogen analysis 9.79 (calc.), 9.73(obs.);
5.12(s, 1H, -CONH).
1
NMR
(CDCl3,
(ppm):
7.10-7.94
154
(m,9H,aromatic), 2.68 (t,2H,RCH2Ar),
stretching), 3364 (NH stretching amide),
5.20
1537 (NH bending amide), 1155, 1309
(s,1H,CONH),
1.28
(m,6H,
cyclohexane).
(S=O stretching), 825 (C-Cl stretching);
N-[4-{2-(benzamido)
ethyl}
phenyl
nitrogen analysis 10.47 (calc.), 10.51
1
sulfonyl]-N’-methyl urea (8)
(obs.);
IR (KBr; cm-1): 3086 (C-H stretching -
(s,2H, Cl-CH2-), 2.42 (t,2H,R-CH2-Ar),
Ar), 787(C-H bending-Ar), 2854 (C-H
6.20(s,1H,CONH).
stretching-Aliphatic),
N-[4-{2-(1-chloro acetamido) ethyl}
1676
(carbonyl
NMR
(CDCl3, (ppm):
3.42
stretching), 3242 (NH stretching amide),
phenyl sulfonyl]-N’-methyl urea(10)
1575 (NH bending amide), 1151, 1361
IR (KBr; cm-1): 2937 (C-H stretching -
(S=O
Ar), 767 (C-H bending-Ar), 2856 (C-H
stretching);
nitrogen
analysis
11.63 (calc.), 11.59 (obs.);
6.84-7.32
NMR
stretching-Aliphatic),
1645
(carbonyl
(m,9H,
stretching), 3366 (NH stretching amide),
aromatic), 2.48 (t,2H,R-CH2-Ar),5.24
1595 (NH bending amide), 1157 (S=O
(s,1H,CONH).
stretching),
N-[4-{2-(1-chloro acetamido) ethyl}
nitrogen
phenyl sulfonyl]-N’-cyclohexyl urea(9)
12.61(obs.); 1NMR (CDCl3, (ppm): 3.48
IR (KBr; cm-1): 2992 (C-H stretching -
(s,2H,Cl-CH2-), 2.42 (t,2H,R-CH2-Ar),
Ar), 760(C-H bending-Ar), 2945 (C-H
5.94
stretching-Aliphatic),
cyclohexane).
(CDCl3,
(ppm):
1
1620
(carbonyl
843
(C-Cl
analysis
(s,1H,CONH),
stretching);
12.61
(calc.),
1.30(m,
6H,
Table 1: Physical data of the title compounds.
Compound no.
Empirical formula
Melting point (0C)
Yield (%)
1
C28H28N3O5S
172
78.45
2
C18H20N3ClO5S
166
74.79
3
C22H26N3O5S
171
54.0
4
C17H18N3O5S
168
44.50
5
C23H29N3O5S
182
53.01
6
C18H21N3O5S
170
45.90
7
C22H27N3O4S
192
72.89
8
C17H19N3O4S
163
42.31
9
C17H24N3O4S
135
25.86
10
C12H16N3O4S
143
29.42
155
Biological activity
control .The second group of animals
Hypoglycemic assay7, 8,9,10
was administered with Glibenclamide
Female sprague dawley rats weighing
(5mg/kg). Remaining group of animals
between 170-250 gm were fasted for 18
received the test compounds at a dose of
hrs with excess water and libitum. The
50mg/kg. Blood glucose concentration
compounds were grounded and 1%
was estimated at 0,1,2,3,4,6,12,24 hours
suspension in carboxymethyl cellulose
by using blood glucose strips and
were prepared and dosed orally by
glucometer. The Mean blood glucose
gavage at 50mg/kg to the rats. The
concentration and the mean percent
animals were divided into three different
reduction
groups of five animals each. First group
calculated and results are tabulated in
received vehicle and served as reference
table1 and 2.
of
glucose
level
were
Table 1 : Mean blood glucose concentration (mg/dl) ± standard error after drug administration.
Treatment
group (n=5)
Time (hours)
3
4
0
1
2
48.24
(±3.61)
55.62
(±2.97)
47.42
(±3.36)
40.34
(±7.06)
46.12
(±2.92)
38.84
(±7.18)
45.34
(±3.44)
32.68
(±5.55)
36.64
(±4.05)
34.88
(±4.92)
36.54
(±6.52)
37.82
(±4.09)
38.81
(±6.72)
31.41
(±4.32)
32.52
(±3.17)
28.66
(±3.96)
34.38
(±6.16)
34.64
(±3.52)
37.84
(±6.18)
29.54
(±3.58)
30.16
(±4.46)
22.42
(±3.52)
30.44
(±7.51)
32.81
(±3.45)
35.53
(±7.28)
24.82
(±3.56)
28.44
(±4.06)
20.85
(±3.70)
29.62
(±7.21)
31.64
(±3.64)
30.57
(±7.28)
21.84
(±2.58)
0
1
2
3
Compound 8
32.24
(±4.14)
28.52
(±4.04)
24.88
(±3.45)
Compound 9
Compound 10
37.40
(±6.66)
39.64
(±4.12)
47.42
35.61
(±5.22)
32.55
(±5.20)
45.22
Standard
(±5.55)
(±5.70)
Control
Compound 1
Compound 2
Compound 3
Compound 4
Compound 5
Compound 6
Compound 7
Treatment
group (n=5)
6
12
24
43.40
(±3.21)
23.12
(±6.35)
42.64
(±4.64)
22.34
(±4.48)
41.52
(±3.34)
19.42
(±8.35)
40.91
(±5.54)
32.34
(±5.24)
27.82
(±3.20)
18.54
(±2.85)
28.92
(±6.74)
30.28
(±3.72)
26.52
(±7.28)
18.20
(±3.82)
26.28
(±3.62)
12.60
(±2.51)
27.96
(±7.16)
28.55
(±3.24)
27.62
(±7.48)
16.25
(±1.48)
15.72
(±4.28)
10.21
(±1.98)
24.74
(±7.24)
20.26
(±3.05)
22.28
(±6.66)
10.44
(±0.89)
28.74
(±4.35)
18.20
(±2.38)
32.76
(±6.54)
26.42
(±4.16)
32.65
(±4.83)
27.22
(±6.66)
4
6
12
24
22.44
(±2.15)
18.50
(±1.52)
16.32
(±1.68)
10.13
(±0.38)
25.20
(±2.89)
27.82
(±7.12)
29.74
(±6.55)
38.64
25.64
(±7.46)
27.66
(±7.54)
32.41
22.83
(±7.58)
26.74
(±5.28)
28.90
20.33
(±6.82)
24.36
(±7.42)
27.62
12.10
(±6.15)
14.54
(±6.60)
15.80
27.82
(±6.15)
34.36
(±7.16)
22.64
(±6.28)
(±6.48)
(±5.72)
(±7.47)
(±4.32)
(±5.43)
Time (hours)
156
Table 2 : Mean percentage reduction of blood glucose ± standard error after
administration of test compounds.
Treatment
group (n=5)
Time (hours)
Control
Compound 1
Compound 2
Compound 3
Compound 4
Compound 5
Compound 6
Compound 7
1
2
3
4
6
12
24
1.52
4.12
6.32
7.21
9.22
12.45
18.65
(±1.92)
(±3.52)
(±4.17)
(±5.54)
(±4.63)
(±5.17)
(±4.20)
26.57
48.28
54.68
60.51
68.30
86.28
58.87
(±8.99)
(±11.38)
(±10.51)
(±9.16)
(±8.24)
9.28
25.24
32.62
42.75
(±3.95)
(±9.27)
(±6.26)
(±5.16)
16.99
18.28
38.80
(±7.68)
(±6.92)
8.58
(±2.42)
(±6.23)
58.58
68.24
48.28
(±7.27)
(±6.15)
(±5.28)
48.35
62.58
88.71
64.48
(±5.74)
(±6.48)
(±4.75)
(±7.43)
(±7.22)
24.34
26.78
30.41
32.68
54.35
25.30
(±5.84)
(±5.34)
(±5.60)
(±3.23)
(±4.54)
18.68
27.68
(±4.58)
9.65
18.32
24.62
34.68
38.24
58.35
38.18
(±2.82)
(±4.92)
(±4.22)
(±5.62)
(±3.86)
(±4.60)
(±5.26)
8.52
14.75
37.12
44.72
52.19
78.25
38.54
(±12.52)
(±12.10)
(±7.10)
(±10.52)
(±7.82)
(±10.17)
38.38
(±4.18)
(±1.46)
(±5.42)
Treatment
group (n=5)
(±5.45)
(±3.24)
42.52
(±4.45)
47.20
(±9.10)
68.84
32.73
(±6.72)
(±12.25)
Time (hours)
1
2
3
4
6
12
24
16.28
27.85
38.45
44.82
48.64
64.72
40.63
Compound8
(±2.14)
(±5.72)
(±4.62)
(±5.18)
(±7.25)
(±8.91)
(±11.20)
Compound 9
4.74
16.45
28.32
33.47
42.83
68.74
47.98
(±1.54)
(±5.76)
(±6.18)
(±7.82)
(±6.26)
(±5.22)
(±5.30)
Compound10
Standard
18.25
28.14
28.58
38.21
54.68
72.38
38.30
(±3.28)
(±5.68)
(±6.26)
(±5.48)
(±4.22)
(±5.20)
(±4.18)
1.82
16.56
22.32
34.84
58.32
72.55
42.74
(±1.34)
(±6.54)
(±5.18)
(±3.75)
(±6.14)
(±6.62)
(±7.23)
RESULTS AND DISCUSSION
experimental
animal
Various analogs of N-[4-{2-(5-chloro-
compounds
showed
2methoxy
ethyl}phenyl
reduction
urea
Compound 1 and 3 were found to
benzamido)
sulfonyl]-N’-cyclohexyl
synthesized
and
purified.
were
These
exhibit
in
blood
good
model.
All
significant
glucose
and
level.
significant
compounds were then characterized by
hypoglycemic activity. Compound 2, 5,
physical, chemical and spectral analysis.
8 and 10 showed comparable activity to
The analogs were also evaluated for
standard Glibenclamide.
hypoglycemic
activity
using
157
ACKNOWLEDGEMENT
5. Furniss BS, Hannaford AJ, Smith
The authors are thankful to Prin. K.M.
PWG and Tatchell AR.In practical
Kundnani College of Pharmacy,Cuffe
organic chemistry.4th Edn, Singapore:
Parade,Mumbai
Pearson Education, 1978,p.157.
for
providing
the
infrastructure and facilities. The authors
6. Biere H, Rufer C,Ahrens H, Loge O
are also thankful to University Science
and Schroder E.J. Med. Chem.1974;
Instrumentation Center, Madurai for
17(7):716.
7. Annamala
providing NMR facility.
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158