Design, synthesis and insulin-sensitizing activity of indomethacin and diclofenac derivatives

Article abstract of DOI:10.1016/j.bmcl.2009.04.050

A series of aromatic acetic acid compounds were designed and synthesized on the basis of Non-steroidal anti-inflammatory drugs indomethacin and diclofenac. Compounds 5a, 7a, 5h, 7h and 17 could strongly promote insulin-regulated differentiation of 3T3-L1 cells in vitro. They acted as full or partial PPARγ agonist, or improved insulin resistance through non-PPARγ pathway.

Full text of DOI:10.1016/j.bmcl.2009.04.050

Bioorganic & Medicinal Chemistry Letters 19 (2009) 3324–3327
Contents lists available at ScienceDirect
Bioorganic & Medicinal Chemistry Letters
journal homepage: www.elsevier.com/locate/bmcl
Design, synthesis and insulin-sensitizing activity of indomethacin
and diclofenac derivatives
Jiquan Zhang a, Jianta Wang a, Haoshu Wu b, Yaoyao He a, Gaofeng Zhu a, Xing Cui a, Lei Tang a,
*
a School of Pharmacy, Guiyang Medical College, Guiyang 550004, China
b College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, 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 aromatic acetic acid compounds were designed and synthesized on the basis of Non-steroidal
Received 6 January 2009
Revised 12 April 2009
Accepted 15 April 2009
Available online 18 April 2009
anti-inflammatory drugs indomethacin and diclofenac. Compounds 5a, 7a, 5h, 7h and 17 could strongly
promote insulin-regulated differentiation of 3T3-L1 cells in vitro. They acted as full or partial PPAR
nist, or improved insulin resistance through non-PPAR pathway.
Ó 2009 Elsevier Ltd. All rights reserved.
c ago-
c
Keywords:
Indomethacin
Diclofenac
PPARc agonist
Insulin resistance
Type 2 diabetes mellitus (T2DM) is a debilitating metabolic dis-
order affecting over 100 million people worldwide,1 which ac-
counts for about 90% of all diabetes. With the total number
projected to rise from 171 million in 2000 to 366 million in
2030,2 diabetes has become a serious health issue threatening
the world population, especially in the developed western
countries.
cell line.6 Indomethacin, although causing certain adverse reaction
to the gastrointestinal system, is widely used as anti-inflammatory
agents today. To the best of our knowledge, indomethacin’s
adverse reaction is due, mostly to its action mechanism, not its
chemical structure. This intrigues us to design a set of new
insulin-sensitizers on the basis of indomethacin for the sake of
avoiding the possible structure-related adverse reactions. There-
fore N-benzoyl-indoleacetic acid group in indomethacin structure
was selected as the core structure in our original design. Some of
the known heterocycle structures in thiazolidinedione insulin sen-
sitizers were attached to this core structure via a linkage of the
alkyloxy group, by replacing the 5-methoxy group. In addition to
indomethacin, one derivative of another NSAIDs diclofenac was
prepared as well.
Scheme 1 shows the synthesis of compounds 5(a–j). Demethyl-
ation of indomethacin with iodotrimethylsilane (TMSI) yielded
compound 2, and the key intermediate 3 was obtained via con-
trolled benzylation of 2. Condensation of 3 with desired heterocy-
clic alcohols via Mitsunobu reaction afforded compounds 4(a–j).
Catalytic hydrogenolysis of 4(a–j) with palladium on carbon gave
the target compounds 5(a–j). Compounds 7(a–j) were prepared
by methyl esterification of 2, followed by coupling with various
heterocyclic alcohols. (Scheme 2).
Insulin resistance (IR) is an important marker for developing
T2DM.3 Improving insulin sensitivity can effectively keep blood
glucose at an appropriate level, thus postpone or avoid the occur-
rence of undesired complications. Several thiazolidine-2, 4-diones
insulin sensitizer such as troglitazone, pioglitazone, rosiglitazone
have been launched into the market since 1997. All these agents
share a common thiazolidine-2,4-dione(TZD) group, and are be-
lieved to mediate their effects via the activation of gamma isoform
of the peroxisome proliferator-activated receptor (PPAR
ever, the adverse toxicity profiles of selective PPAR agonists have
c
).4 How-
c
raised critical safety issues. Studies of the mechanisms responsible
for these toxicities have not shown clearly whether these side ef-
fects identified are target- or compound-related.5 We believe that
identification of a novel non-TZD insulin-sensitizer with a better
pharmacological profile could provide a suitable therapeutic op-
tion for T2DM.
Some recent studies have revealed that indomethacin and other
non-steroidal anti-inflammatory drugs (NSAIDs) possess, to some
extent, activities of insulin-elicited differentiation of preadipocyte
The synthesis of diclofenac derivative 17 is shown in Scheme 3.
Starting from m-nitrophenol, compound 10 was synthesized by
four steps of methylation, reduction, diazotization and iodination.
Condensation of 10 with 2,6-dichlorobenzenamine followed by
chloroacetylation, Friedel–Crafts reaction and hydrolization affor-
ded compound 14. Esterification of 14 with methanol-p-methyl-
* Corresponding author. Tel.: +86 851 6908568.
E-mail address: tlei1974@hotmail.com (L. Tang).
0960-894X/$ - see front matter Ó 2009 Elsevier Ltd. All rights reserved.
doi:10.1016/j.bmcl.2009.04.050

J. Zhang et al. / Bioorg. Med. Chem. Lett. 19 (2009) 3324–3327
3325
Scheme 1. Reagents: (a) iodotrimethylsilane, CHCl3, 61%; (b) benzyl bromide, K2CO3, DMF, 47%; (c) R1–OH, Ph3P, diethyl azodicarboxylate, Et2O; (d) H2, Pd–C(10%), THF.
ters displayed better activities than the corresponding carboxylic
acids. With the elongation of left lipophilic chain, the insulin-sen-
sitizing effect was enhanced. Comparisons between 5f and 5h, 7f
and 7h, 5h and 5i, 7h and 7i, show that para electron-donating
substitutions on the phenyl ring also potentially increase the effi-
ciency, which agrees well with literature observations on other
types of insulin-sensitizers reported previously.9 This may be due
to additional sterical effects introduced by the substitution groups,
which could provide a more suitable conformation for their bind-
ing, Comparing 5f and 5j, 7f and 7j, we found that a meta elec-
Scheme 2. Reagents: (a) SOCl2, CH3OH, 44%; (b) R1–OH, Ph3P, diethyl azodicar-
boxylate, Et2O.
tron-withdrawing and electron-donating conjugated substitution
on the phenyl ring resulted in an increase of the insulin-sensitizing
activity.
Compound 7h possesses the strongest PPARc agonist efficacy
benzenesulfonic acid gave intermediate 15. Benzylation of 15 with
benzyl bromide followed by hydrolysis produced the target com-
pound 17.
The insulin-sensitizing activity of all above synthesized com-
pounds was screened by measuring the triglyceride accumulation
resulting from insulin-regulated differentiation of 3T3-L1 cells.7
Rosiglitazone was chosen as a positive control. The activities of
the screened compounds are given as percentages to the data ob-
tained from rosiglitazone, with the insulin-sensitizing activity of
(Emax) in the transactivation assays, higher than that of the positive
control rosiglitazone, and compounds 5f, 7f, 5h show comparable
transactivation activities as well. These findings are consistent
with the results we reported in a previous paper where phenyl
or biphenyl oxazolylethanol were used as replacement.9 Surpris-
ingly, compounds 5a and 7a, despite their highly insulin-sensitiz-
ing activities in 3T3-L1 cells, were inactive in the transactivation
assays. This finding indicates that, 5a and 7a may improve their
insulin resistances via a mechanism different from that of PPAR
c
which at 1 lM concentration designated as 100%. (Table 1). The
agonist. Exceptional behaviors were also observed for diclofenac
EC30 values (effective concentration for 30% enhancement of insu-
lin-induced triglyceride accumulation in 3T3-L1 cells) of some
compounds were also given. Compounds with good insulin-sensi-
tizing activities, including 5a, 7a, 5f, 7f, 5h, 7h and 17, were chosen
derivative 17, with a comparable potent insulin-sensitizing activity
in 3T3-L1 cells, while exhibiting only weak PPARc agonist activity
in the transactivation assays. Given its maximal activity in transac-
tivation assays, compound 17 can be assumed to be a PPAR
c
partial
partial
and evaluated for activity at human PPARc by using an established
agonist. In the research of novel insulin-sensitizer, PPAR
c
cellbased transactivation assay in U2OS cells.8 The results (listed in
Table 1) were compared with the reference compound rosiglitaz-
one. The activating efficacy of the tested compounds was judged
by the maximal activation and given as the percentage to the data
obtained from the reference compound. The activating potency of
the tested compounds was expressed as EC50 (the concentration
at which 50% of the maximum activation was observed).
agonist was believed to possess many advantages in safety aspect
compared to PPAR
c
full agonist.10 For these reasons compounds 7a
and 17 can be taken as leading compounds for future insulin-sen-
sitizer research work.
In summary, we have demonstrated that NSAIDs indomethacin
and diclofenac derivatives possess potent insulin-sensitizing in
3T3-L1 cells, via functioning as full or partial PPAR
Surprisingly, some compounds show even improved insulin resis-
tance, probably via a non-PPAR pathway. It is worth anticipating
c agonists.
As described in Table 1, 5a,11 7a, 5h and 7h12 exhibited more
potent insulin-sensitizing activity than rosiglitazone, indicated by
their higher EC30 values, and 7d, 7f, 7j and 1713 also showed com-
parable activities. The most potential triglyceride accumulation
c
that more new type of compounds with potent insulin-sensitizing
activity can be discovered on the basis of other NSAIDs. Com-
pounds 5a, 7a, 7h and 17, possessing good insulin-sensitizing
activity, can be taken for further pharmacological evaluations, or
enhancement at 1
lM was given by compound 7h, 1.38-fold higher
than that of rosiglitazine. It should be noted that in general the es-

3326
J. Zhang et al. / Bioorg. Med. Chem. Lett. 19 (2009) 3324–3327
Scheme 3. Reagents: (a) CH3I, K2CO3, acetone, 98%; (b) Fe–HCl, EtOH; 95.5%; (c) (1) H2SO4, THF; (2) H2SO4, NaNO2 aqueous; (3) KI aqueous, 68.%; (d) 2,6-
dichlorobenzenamine, Cu, CuI, K2CO3, NMP, 58%; (e) 2-chloroacetyl chloride; (f) AlCl3, 71%; (g) 10% NaOH aqueous, 75%; (h) methanol, p-methylbenzenesulfonic acid, 72%; (i)
benzyl bromide, K2CO3, 75%; (j) EtOH–NaOH, HCl aqueous, 36%.
Table 1
Data of insulin-sensitizing activity and PPAR
c
activity in vitro for compounds
R1O
COOR2
N
O
Cl
Compd
R1
R2
Insulin-sensitizing activity
PPAR-c
Triglyceride accumulation at 1
l
Ma
EC30(M)b
EC50(M)
% max
5a
7a
H
CH3
126
134
9.51Â10À9
6.56Â10À9
iac
ia
ia
ia
5b
7b
H
CH3
30
33
—
—
N
O
5c
7c
H
CH3
36
42
—
—
N
CH3
CH3
H3C
5d
7d
H
CH3
74
81
6.92Â10À7
2.88Â10À7
CH3

J. Zhang et al. / Bioorg. Med. Chem. Lett. 19 (2009) 3324–3327
3327
Table 1 (continued)
Compd
R1
R2
Insulin-sensitizing activity
PPAR-c
Triglyceride accumulation at 1
l
Ma
EC30(M)b
EC50(M)
% max
O
O
5e
7e
H
CH3
41
47
—
—
N
CH3
O
5f
7f
H
CH3
36
80
6.17Â10À6
2.75Â10-7
1.23
0.62
79
74
N
Et
5g
7g
H
CH3
42
50
5.89Â10À6
1.70Â10À6
N
CH3
O
5h
7h
H
CH3
129
138
3.31Â10À8
1.23Â10À8
0.04
0.02
134
141
Ph
Cl
N
CH3
CH3
O
N
5i
7i
H
CH3
38
57
—
2.00Â10À6
O
N
5j
7j
H
CH3
76
85
3.75Â10À7
3.16Â10À7
H3CO
COOH
NH
O
17
98
2.51Â10À7
1.05Â10À7
6.03
0.01
35
Cl
Cl
Rosiglitazone
% Activity of rosiglitazone at 1
100
100
a
l
M, Values are means of three experiments.
Effective concentration for 30% enhancement of insulin-induced triglyceride accumulation in 3T3-L1 cells.
b
c
ia: inactive.
7. Shinkai, H. et al J. Med. Chem. 1998, 41, 1927.
8. Li, Z. B. et al Bioorg. Med. Chem. Lett. 2004, 14, 3507.
9. Yu, J. H.; Tang, L.; Yang, Y. Y.; Ji, R. R. Eur. J. Med. Chem. 2008, 43,
2428.
as interesting leading compounds for further studies due to their
presumably different acting mechanism.
10. Anne, R.; Rémy, H.; Dean, W. H.; Jean, C. F.; Bart, S. Biochim. Biophys. Acta 2007,
1771, 1065.
Acknowledgments
11. Data of 5a: white crystals, mp 170–173 °C, 1H NMR (CDCl3, 400 MHz) d 7.67 (d,
J = 8.4 Hz, 2H), 7.47 (d, J = 8.8 Hz, 2H), 7.38 (m, 5H), 7.05 (d, J = 2.4 Hz, 1H), 6.86
(d, J = 9.2 Hz, 1H), 6.75 (dd, J = 11.2 Hz, 1H), 5.07 (s, 2H), 3.68 (s, 2H), 2.39 (s,
3H). Anal. Calcd. for C25H20ClNO4: C, 69.20; H, 4.65; N, 3.23. Found: C, 69.35; H,
4.51; N, 3.50.
Financial support by the Provincial Social Development Founda-
tion of Guizhou, China (2008-3039) is acknowledged. The authors
acknowledge Shenzhen Chipscreen Biosciences Ltd. for the
in vitro assays.
12. Data of 7h: white crystals, mp 113–114 °C; 1H NMR (CDCl3, 400 MHz) d 8.07 (d,
J = 8.4 Hz, 2H), 7.68 (d, J = 8.0 Hz, 2H), 7.64 (d, J = 7.2 Hz, 4H), 7.46 (m, 4H), 7.38
(t, J = 7.6 Hz, 1H), 6.97 (d, J = 2.0 Hz, 1H), 6.85 (d, J = 8.8 Hz, 1H), 6.67 (dd,
J = 8.8 Hz, 1H), 4.30 (t, J = 6.8 Hz, 2H), 3.70 (s, 3H), 3.65 (s, 2H), 3.03 (t,
J = 6.4 Hz, 2H), 2.41 (s, 3H), 2.37 (s, 3H); Anal. Calcd. for C37H31ClN2O5: C, 71.78;
H, 5.05; N, 4.52. Found: C, 71.89; H, 5.22; N, 4.29.
References and notes
1. Amos, A. F.; McCarty, D. J.; Zimmet, P. Diabetes Metab. 1997, 14, S5.
2. S, Wild; G, Roglic; A, Green; R, Sicree; King, H. Diabetes Care 2004, 27, 1047.
3. Hai, L. Z.; Hisashi, M.; Seikou, N.; Masayuki, Y. Bioorg. Med. Chem. Lett. 2008, 18,
3272.
4. Harold, E. L. Diabetes Metab. Res. Rev. 2002, 18, S23.
5. Young, G. S. et al J. Med. Chem. 2008, 51, 6318.
13. Data of 17: brown solid, mp 149–150 °C; 1H NMR (DMSO-d6, 400 MHz) d 3.59
(s, 2H), 4.91 (s, 2H), 5.78 (t, 1H), 6.49–6.52 (dd, J = 2.4 Hz, 4.4 Hz, 1H), 7.09 (d,
J = 7.2 Hz, 1H), 7.18–7.24 (m, 1H), 7.27–7.31 (m, 4H), 7.51 (d, J = 8.0 Hz, 7H).
Anal. Calcd. for C21H17Cl2NO3: C, 62.70; H, 4.26; N, 3.48. Found: C, 60.52; H,
4.30; N, 4.29.
6. Magdalena, S. et al Proc. Natl. Acad. Sci. U.S.A. 2006, 103, 443.