Diclofenac derivatives with insulin-sensitizing activity

Article abstract of DOI:10.1016/j.cclet.2010.11.008

A series of diclofenac derivatives were synthesized. The insulin-sensitizing activity of 28 new compounds was evaluated in 3T3-L1 cells. The compounds 10a and 10f exhibited similar insulin-sensitizing activity with positive drug rosiglitazone.

Full text of DOI:10.1016/j.cclet.2010.11.008

Available online at www.sciencedirect.com
Chinese Chemical Letters 22 (2011) 409–412
www.elsevier.com/locate/cclet
Diclofenac derivatives with insulin-sensitizing activity
Jian Ta Wang, Ying Wang, Ji Quan Zhang, Xing Cui, Yi Zhang, Gao Feng Zhu,
*
Lei Tang
School of Pharmacy, Guiyang Medical College, Guiyang 550004, China
Received 15 July 2010
Available online 17 January 2011
Abstract
A series of diclofenac derivatives were synthesized. The insulin-sensitizing activity of 28 new compounds was evaluated in 3T3-
L1 cells. The compounds 10a and 10f exhibited similar insulin-sensitizing activity with positive drug rosiglitazone.
# 2010 Lei Tang. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.
Keywords: Diclofenac derivatives; Synthesis; Insulin-sensitizing activity
Type 2 diabetes mellitus (T2DM) is a chronic metabolic disorder characterized by hyperglycemia as well as insulin
resistance. Recently T2DM was also presumed as a chronic inflammation disease [1]. Studies showed that
inflammatory cytokines such as C-reactive protein (C-RP), interleukins (ILs), tumor necrosis factor-alpha (TNF-a),
plasminogen activator inhibitor type 1 (PAI-1) probably play a major role in the development of insulin resistance,
which is known as important pathologic factor that lead to T2DM [2]. Improving insulin sensitivity can not only
effectively keep blood glucose at an appropriate level, but also postpone or avoid the occurrence of undesired
complications.
Some recent studies have revealed that non-steroidal anti-inflammatory drugs (NSAIDs) possessed some extent of
insulin-sensitizing activity [3]. Studies showed that NSAIDs can control inflammation by inhibiting the expression of
inflammatory factors and mediators of inflammation [4]. These findings aroused our interest to search new insulin
sensitizers by structure modification of NSAIDs. In our preliminary work, NSAIDs diclofenac’s derivative 10a was
found having a similar insulin-sensitizing activity with positive control rosiglitazone [5]. However, compound 10a
only showed a weak agonist activity on peroxisome proliferator-activated receptor g (PPARg), which is a common
target receptor of many kinds of insulin-sensitizers. This result suggests that diclofenac acid derivatives might have
different insulin-sensitizing mechanisms. Herein we reported the synthesis and insulin-sensitizing activities of more
diclofenac derivatives.
Synthetic route of diclofenac derivatives was shown in Scheme 1. According to different substitute positions on the
phenyl cycle of the target compounds, p-nitrophenol or m-nitrophenol was used as the starting material. The key
intermediate 7 was prepared referring to the synthesis of diclofenac through 7 steps of reaction. Compound 8 was
* Corresponding author.
E-mail address: tlei1974@hotmail.com (L. Tang).
1001-8417/$ – see front matter # 2010 Lei Tang. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.
doi:10.1016/j.cclet.2010.11.008

[()TD$FIG]
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J.T. Wang et al. / Chinese Chemical Letters 22 (2011) 409–412
Scheme 1. Synthetic route for declofenac derivatives. Reagents: (a) CH3I, K2CO3, acetone, reflux, 4–6 h, 96–98%; (b) Fe–HCl, EtOH, reflux, 4–
6.5 h, 87.8–95.5%; (c) (1) H2SO4, THF, 0 8C; (2) H2SO4, NaNO2 aqueous, 0 8C, 0.5 h; (3) KI aqueous, 0 8C, 1 h, reflux, 2 h, 49.7–72.1%; (d) 2,6-
dichlorobenzenamine, Cu, CuI, K2CO3, NMP, 160 8C, 40 h, 45.1–56.8%; (e) 2-chloroacetyl chloride, 105 8C, 1.5 h, 71.3–88.5%; (f) AlCl3, N2,
250 8C, 0.5 h, 160 8C, 2 h, 74.3–84.9%; (g) 10% NaOH aqueous, reflux, 2 h, 71–75%; (h) methanol, p-methylbenzenesulfonic acid, 80 8C, 3 h, 68–
72%; (i) R–OH, Ph3P, diethyl azodicarboxylate, Et2O, r.t., 16–30 h, 31.5–77.3%; (j) THF–NaOH, HCl aqueous, r.t., 6–24 h, 27.9–72.1%.
Table 1
Increasing percentage of triglyceride in 3T3-L1 cell.[TD$INLE]
5
COOR
Cl
1
R
O
NH
4
Cl
Compound
R
R-position
R1
Insulin-sensitizing activity
10À9 mol/L
10À5 mol/L
9a
]
4
4
5
5
CH3
H
4.8 Æ 3.8
5.1 Æ 0.6
4.2 Æ 1.5
5.0 Æ 1.5
88.7 Æ 22.4
92.1 Æ 21.7
35.3 Æ 2.0
79.8 Æ 6.5
10a
9b
CH3
H
10b
9c
]
4
4
5
5
CH3
H
3.5 Æ 1.7
4.4 Æ 4.1
4.9 Æ 0.9
5.0 Æ 2.6
35.2 Æ 9.6
59.6 Æ 24.4
46.5 Æ 16.5
67.7 Æ 5.8
10c
9d
CH3
H
10d
F

J.T. Wang et al. / Chinese Chemical Letters 22 (2011) 409–412
411
Table 1 (Continued )
Compound
R
R-position
R1
Insulin-sensitizing activity
10À9 mol/L
10À5 mol/L
9e
]
4
4
5
5
CH3
H
4.5 Æ 1.4
4.8 Æ 3.7
5.0 Æ 1.2
5.5 Æ 1.0
33.3 Æ 12.5
75.7 Æ 24.9
80.5 Æ 5.3
92.3 Æ 7.6
10e
9f
CH3
H
10f
F3C
9g
]
4
4
5
5
CH3
H
4.2 Æ 7.0
5.2 Æ 1.2
4.6 Æ 1.5
5.9 Æ 1.3
25.4 Æ 10.0
43.9 Æ 12.2
80.4 Æ 4.8
78.4 Æ 4.5
10g
9h
CH3
H
10h
N
9i
]
4
4
5
5
CH3
H
4.0 Æ 3.0
7.0 Æ 4.8
5.3 Æ 1.4
6.0 Æ 1.5
58.7 Æ 15.6
81.4 Æ 6.1
19.5 Æ 16.0
89.7 Æ 8.6
10i
9j
O
N
CH3
H
10j
9k
]
4
4
5
5
CH3
H
2.1 Æ 3.5
3.9 Æ 1.5
3.7 Æ 1.4
2.8 Æ 4.5
39.8 Æ 20.8
40.0 Æ 5.8
74.5 Æ 8.7
68.5 Æ 3.9
10k
9l
CH3
H
10l
N
9m
10m
9n
]
4
4
5
5
CH3
H
5.0 Æ 2.1
4.3 Æ 1.6
0.7 Æ 2.2
4.5 Æ 1.2
64.1 Æ 17.0
42.6 Æ 5.1
65.3 Æ 23.1
47.3 Æ 2.7
F
F
CH3
H
10n
F
Rosiglitazone
5.3 Æ 1.9
93.7 Æ 9.8
obtained via methyl esterification of 7 [5]. Condensation of 8 with desired alcohol via Mitsunobu reaction provided
compounds 9a–n. Saponification of 9a–n with NaOH (aq.) to give the target compounds 10a–n, respectively [6].
All synthesized compounds were screened for insulin-sensitizing activity by measuring the triglyceride
accumulation resulting from insulin-regulated differentiation of 3T3-L1 cells [7]. The marketed insulin-sensitizing
drug rosiglitazone was selected as positive control. The activities data are presented in Table 1. As indicated in Table 1,
at concentration of 10À5 mol/L, compounds 10a and 10f showed similar promoting differentiation activity with
positive drug rosiglitazone. There is no obvious activity regularity by comparing compounds with substitution on 4- or
5-position of the phenyl cycle. In most cases, the activities of those compounds with a free carboxyl group were higher
than their corresponding methyl ester derivatives.
In summary, we have discovered a novel class of diclofenac derivatives which possess potent insulin-sensitizing
activity, and they may be used as candidate compounds in the development of antidiabetic agents. The inhibiting
activity test of diclofenac derivatives on the expression of inflammatory factors is ongoing presently.
Acknowledgments
The research work was supported by National Natural Science Foundation (No. 30960462), Guizhou Social
Development Scientific Foundation (No. 2008-3039), Governor’s Foundation for Excellent Scientific and Educational
Talents of Guizhou (No. 2009-81) and Excellent Youth Scientific Talents Foundation of Guizhou (No. 2009-24).
References
[1] J.C. Pcikup, M.A. Crook, Diabetologia 41 (1998) 1241.
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J.T. Wang et al. / Chinese Chemical Letters 22 (2011) 409–412
[3] S. Magdalena, D. Ilse, R. Steffen, et al. Proc. Natl. Acad. Sci. U.S.A. 103 (2006) 443.
[4] B. Zhang, G.H. Du, Chin. Pharm. Bull. 21 (2005) 905.
[5] Q.J. Zhang, J.T. Wang, H.S. Wu, et al. Bioorg. Med. Chem. Lett. 19 (2009) 3324.
[6] Physical and spectral data for some diclofenac derivatives: 10f: pale yellow solid, mp 125–127 8C; IR (KBr, cmÀ1): 3335, 3200 (br), 1690, 1569,
1514, 1439, 1376; 1H NMR (400 MHz, DMSO-d6): d 3.71 (s, 2H), 5.15 (s, 2H), 6.33 (d, 1H, J = 8.8 Hz), 6.78 (dd, 1H, J = 2.8 Hz, 8.8 Hz), 6.92
(s, 1H), 6.98 (d, 1H, J = 2.8 Hz), 7.11 (t, 1H, J = 8.0 Hz), 7.47 (s, 1H), 7.49 (s, 1H), 7.66 (d, 2H, J = 8.0 Hz), 7.76 (d, 2H, J = 8.4 Hz), 12.75 (br,
1H); EI-MS (m/z): 469 (M+), 310, 292, 159; Anal. calcd. for C22H16Cl2F3NO3: C, 56.19; H, 3.43; N, 2.98, Found: C, 56.20; H, 3.32; N, 2.95;
10h: off-white solid, mp 139–142 8C; IR (KBr, cmÀ1): 3344, 2965, 2947, 1712, 1615, 1586, 1517, 1454; 1H NMR (400 MHz, DMSO-d6): d 1.19
(t, 3H), 2.59 (q, 2H), 3.11 (t, 2H, J = 6.4 Hz), 3.68 (s, 2H), 4.13 (t, 2H, J = 6.6 Hz), 6.37 (d, 1H, J = 8.4 Hz), 6.62 (d, 1H, J = 8.4 Hz), 6.79 (s, 1H),
6.88 (t, 1H, J = 8.0 Hz), 7.25 (d, 1H, J = 8.0 Hz), 7.36–7.42 (m, 2H), 7.56 (d, 1H, J = 8.0 Hz), 8.36 (s, 1H); EI-MS (m/z): 311, 230, 133, 118;
Anal. calcd. for C23H22Cl2N2O3: C, 62.03; H, 4.98; N, 6.29, Found: C, 62.19; H, 5.10; N, 6.26;10i: off-white solid, mp 130–133 8C; IR (KBr,
cmÀ1): 3333, 3300 (br), 1703, 1616, 1588, 1518, 1453; 1H NMR (400 MHz, DMSO-d6): d 2.30 (s, 3H), 2.93 (t, 2H, J = 6.8 Hz), 3.59 (s, 2H),
4.00 (t, 2H, J = 6.7 Hz), 6.10 (d, 1H, J = 2.0 Hz), 6.49–6.51 (dd, 1H, J = 2.4 Hz, 2.0 Hz), 6.93 (s, 1H), 6.99 (m, 1H), 7.18 (d, 1H, J = 8.4 Hz),
7.35 (d, 2H, J = 8.4 Hz), 7.52 (m, 3H), 7.96 (d, 2H, J = 8.4 Hz); EI-MS (m/z): 417, 186, 104, 43; Anal. calcd. for C26H22Cl2N2O4: C, 62.79; H,
4.46; N, 5.63, Found: C, 62.63; H, 4.56; N, 5.75; 10j: off-white solid, mp 137–138 8C; IR (KBr): 3342, 3200 (br), 1741, 1623, 1580, 1506, 1450;
1H NMR (400 MHz, DMSO-d6): d 2.36 (s, 3H), 2.90 (t, 2H, J = 6.6 Hz), 3.68 (s, 2H), 4.15 (t, 2H, J = 6.4 Hz), 6.32 (d, 1H, J = 8.8 Hz), 6.70 (dd,
1H, J = 2.8 Hz, 8.8 Hz), 6.88 (d, 1H, J = 13.2 Hz), 7.06–7.10 (m, 1H), 7.46–7.51 (m, 6H), 7.92 (m, 2H), 12.85 (br, 1H); EI-MS (m/z): 478, 186,
104, 43; Anal. calcd. for C26H22Cl2N2O4: C, 62.79; H, 4.46; N, 5.63, Found: C, 62.83; H, 4.49; N, 5.73.
[7] 3T3-L1 cells were obtained from Shanghai Institute of Biochemistry and Cell Biology and maintained at 37 8C in an atmosphere of 5% CO2 in
Dulbecco’s modified Eagle medium (DMEM, Gibco) containing 10% fetal bovine serum (FBS). The 3T3-L1 pre-adipocytes were grown in 96-
well plates until 2 days postconfluence. The differentiation was induced by addition of 5 mg/mL insulin (Lilly), 0.5 mmol/L isobutylmethyl-
xanthine and 1 mmol/L dexamethasone (Sigma). The induction medium was removed 2 days after incubation. After an additional 2 days of
incubation in DMEM supplemented with 10% FBS and 5 mg/mL insulin, the medium was changed every other day with DMEM supplemented
with 10% FBS. Cells were challenged during the first 4 days of differentiation with different compounds at 10 mmol/L, with rosiglitazone as
positive control and 0.1% DMSO as negative control. The addition of compounds to the medium was accomplished by dissolving the drug in
DMSO and diluting the drug 1000-fold with medium. 7 days after the induction of 3T3-L1 cells, Oil Red O staining was used to detect
triglyceride accumulation in 3T3-L1 cells. The precipitation of Oil Red O in 3T3-L1 adipocytes was dissolved with isopropyl alcohol, and OD
value at 510 nm was determined by ELISA spectrometry. The results were based on 3 independent experiments.