A Short and Efficient Synthesis of the Pharmacological Research Tool GW501516 for the Peroxisome Proliferator-Activated Receptor δ

Article abstract of DOI:10.1021/jo035140g

The most potent and selective peroxisome proliferator-activated receptor δ (PPARδ) agonist GW501516 (1) was synthesized in 4 steps and 78% overall yield starting from o-cresol by using a one-pot regiocontrolled dialkylation of mercaptophenol 5 as the key

Full text of DOI:10.1021/jo035140g

selective ligands for use as chemical tools is essential to
elucidating the function of PPARδ. However, all of the
ligands published to date either have low affinity for
PPARδ or lack selectivity over the other PPAR isoforms,5
except GW501516 (1) and its analogue GW0742 (2) which
were recently discovered by combinatorial chemistry and
structure-based drug design.6 These two compounds were
shown to be the most potent and selective PPARδ
agonists known with an EC50 of 1.1 nM against PPARδ
and 1000-fold selectivity over the other human subtypes,
PPARR and -γ. Thus, these two ligands could be used as
ideal chemical tools to study the function of the ubiqui-
tously expressed PPARδ.7
A Sh or t a n d Efficien t Syn th esis of th e
P h a r m a cologica l Resea r ch Tool GW501516
for th e P er oxisom e P r olifer a tor -Activa ted
Recep tor δ
Zhi-Liang Wei and Alan P. Kozikowski*
Drug Discovery Program, Department of Neurology,
Georgetown University Medical Center,
3900 Reservoir Road, NW, Washington, D.C. 20057
kozikowa@georgetown.edu
Received August 1, 2003
However, the reported synthesis of 1 and 2 involved
more than eight steps with about 7% overall yield,
respectively.6 Thus, a more efficient synthesis of these
compounds is needed. Herein, we present a short and
efficient method to synthesize GW501516 (1).
Abstr a ct: The most potent and selective peroxisome pro-
liferator-activated receptor δ (PPARδ) agonist GW501516
(1) was synthesized in 4 steps and 78% overall yield starting
from o-cresol by using a one-pot regiocontrolled dialkylation
of mercaptophenol 5 as the key step.
The peroxisome proliferator-activated receptors (PPARs)
are ligand-activated transcription factors belonging to the
nuclear receptor gene family that function as het-
erodimers with the 9-cis-retinoic acid receptor (RXR).1,2
Three closely related isoforms, PPARR, -γ, and -δ (or -â),
have been identified in organisms ranging from Xenopus
to humans. Each PPAR subtype appears to be differen-
tially expressed in a tissue-specific manner, with PPARR
and PPARγ predominating in the liver and adipocytes,
respectively, and PPARδ being ubiquitously expressed.
Since the first discovery of PPARR as an orphan recep-
tor,3 the biology of the PPARs has been driven, in large
part, by the availability of potent and selective ligands
for the receptors.1 PPARR, which was recognized to be
the target receptor for the fibrate class of anti-hyperlipi-
demic drugs, regulates the expression of genes involved
in lipid metabolism. PPARγ, which was shown to function
as the cellular receptor of the thiazolidinedione (TZD)
class of insulin-sensitizing drugs, is an important regula-
tor of adipogenesis, lipid metabolism, and glucose ho-
meostasis. In contrast to PPARR and -γ, there are no
marketed drugs that target PPARδ, and the physiological
role of PPARδ remains largely mysterious due, in part,
to the lack of selective ligands as chemical tools to study
its pharmacology.4 Thus, identification of potent and
Our synthesis of 1 is illustrated in Scheme 1. Treat-
ment of o-cresol (3) with NaSCN and bromine afforded
the thiocyanate 4 in 97% yield,8 which was reduced to
the mercaptophenol 5 with LiAlH4.9 Treatment of 5 with
Cs2CO3 and chloromethyl thiazole 66 in acetonitrile at
room temperature for 4 h followed by adding more Cs2-
CO3 and methyl bromoacetate (7) provided 8 in 96% yield.
The ester 8 was saponified with aqueous LiOH to give
GW501516 (1) in 98% yield.
(5) (a) Forman, B. M.; Chen, J .; Evans, R. M. Proc. Natl. Acad. Sci.
U.S.A. 1997, 94, 4312. (b) Brown, P. J .; Smith-Oliver, T. A.; Charifson,
P. S.; Tomkinson, N. C. O.; Fivush, A. M.; Sternbach, D. D.; Wade, L.
E.; Orband-Miller, L.; Parks, D. J .; Blanchard, S. G.; Kliewer, S. A.;
Lehmann J . M.; Willson, T. M. Chem. Biol. 1997, 4, 909. (c) Berger,
J .; Leibowitz, M. D.; Doebber, T. W.; Elbrecht, A.; Zhang, B.; Zhou, G.;
Biswas, C.; Cullinan, C. A.; Hayes, N. S.; Li, Y.; Tanen, M.; Ventre, J .;
Wu, M. S.; Berger, G. D.; Mosley, R.; Marquis, R.; Santini, C.; Sahoo,
S. P.; Tolman, R. L.; Smith, R. G.; Moller, D. E. J . Biol. Chem. 1999,
274, 6718. (d) J ohnson, T. E.; Holloway, M. K.; Vogel, R.; Rutledge, S.
J .; Perkins, J . J .; Rodan, G. A.; Schmidt, A. J . Steroid Biochem. Mol.
Biol. 1997, 63, 1. (e) Brooks, C. D. W.; Summers, J . B. J . Med. Chem.
1996, 39, 2629.
* To whom correspondence should be addressed. Phone: 202-687-
0686. Fax: 202-687-5065.
(1) Willson, T. M.; Brown, P. J .; Sternbach, D. D.; Henke, B. R. J .
Med. Chem. 2000, 43, 527.
(2) Shearer, B. G.; Hoekstra, W. J . Curr. Med. Chem. 2003, 10, 267.
(3) Issemann, I.; Green, S. Nature 1990, 347, 645.
(4) (a) Wang, Y.-X.; Lee, C.-H.; Tiep, S.; Yu, R. T.; Ham, J .; Kang,
H.; Evans, R. M. Cell 2003, 113, 159. (b) Di-Po¨ı, N.; Tan, N. S.;
Michalik, L.; Wahli, W.; Desvergne, B. Mol. Cell 2002, 10, 721. (c)
Vosper, H.; Patel, L.; Graham, T. L.; Khoudoli, G. A.; Hill, A.; Macphee,
C. H.; Pinto, I.; Smith, S. A.; Suckling, K. E.; Wolf, C. R.; Palmer, C.
N. A. J . Biol. Chem. 2001, 276, 44258. (d) Tan, N. S.; Michalik, L.;
Noy, N.; Yasmin, R.; Pacot, C.; Heim, M.; Flu¨hmann, B.; Desvergne,
B.; Wahli, W. Genes Dev. 2001, 15, 3263. (e) Leibowitz, M. D.; Fie´vet,
C.; Hennuyer, N.; Peinado-Onsurbe, J .; Duez, H.; Berger, J .; Cullinan,
C. A.; Sparrow, C. P.; Baffic, J .; Berger, G. D.; Santini, C.; Marquis,
R. W.; Tolman, R. L.; Smith, R. G.; Moller, D. E.; Auwerx, J . FEBS
Lett. 2000, 473, 333.
(6) Sznaidman, M. L.; Haffner, C. D.; Maloney, P. R.; Fivush, A.;
Chao, E.; Goreham, D.; Sierra, M. L.; LeGrumelec, C.; Xu, H. E.;
Montana, V. G.; Lambert, M. H.; Willson, T. M.; Oliver, W. R., J r.;
Sternbach, D. D. Bioorg. Med. Chem. Lett. 2003, 13, 1517.
(7) Oliver, W. R., J r.; Shenk, J . L.; Snaith, M. R.; Russell, C. S.;
Plunket, K. D.; Bodkin, N. L.; Lewis, M. C.; Winegar, D. A.; Sznaidman,
M. L.; Lambert, M. H.; Xu, H. E.; Sternbach, D. D.; Kliewer, S. A.;
Hansen, B. C.; Willson. T. M. Proc. Natl. Acad. Sci. U.S.A. 2001, 98,
5306.
(8) Boyer, F. E.; Vara Prasad, J . V. N.; Domagala, J . M.; Ellsworth,
E. L.; Gajda, C.; Hagen, S. E.; Markoski, L. J .; Tait, B. D.; Lunney, E.
A.; Palovsky, A.; Ferguson, D.; Graham, N.; Holler, T.; Hupe, D.;
Nouhan, C.; Tummino, P. J .; Urumov, A.; Zeikus, E.; Zeikus, K.;
Gracheck, S. J .; Sanders, J . M.; VanderRoest, S.; Brodfuehrer, J .; Iyer,
K.; Sinz, M.; Gulnik, S. V.; Erickson, J . W. J . Med. Chem. 2000, 43,
843.
(9) Robillard, B.; Hughes, L.; Slaby, M.; Lindsay, D. A.; Ingold, K.
U. J . Org. Chem. 1986, 51, 1700.
10.1021/jo035140g CCC: $25.00 © 2003 American Chemical Society
Published on Web 10/10/2003
9116
J . Org. Chem. 2003, 68, 9116-9118

SCHEME 1
by adding moist THF, water, and 1.0 M HCl. The mixture was
extracted with EtOAc (3 × 100 mL). The organic layers were
combined, washed with brine, dried (MgSO4), and concentrated.
The residue was purified by column chromatography on silica
gel with hexane/ethyl acetate (4:1) to give 5 as a white solid (4.4
In summary, a practical synthesis of 1 was accom-
plished in 78% overall yield by using a one-pot regiocon-
trolled dialkylation of mercaptophenol 5 as the key step.
Our synthetic route not only is short and efficient but
also provides an alternative strategy to procure the
mercaptophenol core structure, thus enabling the prepa-
ration of additional analogues for further structure-
activity relationship studies.
1
g, 86%). Mp 41-42 °C (lit.11 mp 39-42 °C); H NMR (CDCl3) δ
7.12 (d, 1H, J ) 2.1 Hz), 7.05 (dd, 1H, J ) 8.1, 2.1 Hz), 6.66 (d,
1H, J ) 8.1 Hz), 4.89 (s, 1H), 3.33 (s, 1H), 2.20 (s, 3H); 13C NMR
(CDCl3) δ 152.7, 133.8, 129.9, 124.9, 119.6, 115.6, 15.6.
Meth yl [2-Meth yl-4-[[[4-m eth yl-2-[4-(tr iflu or om eth yl)-
p h en yl]th ia zol-5-yl]m eth yl]su lfa n yl]p h en oxy]a ceta te (8).
To a stirred solution of 5 (1.40 g, 10.0 mmol) in CH3CN (80 mL)
was added Cs2CO3 (3.25 g, 10.0 mmol), followed by the chlo-
romethylthiazole 6 (2.60 g, 8.91 mmol).6 The reaction mixture
was stirred at room temperature for 4 h. Then additional Cs2-
CO3 (4.89 g, 15.0 mmol) was added, followed by methyl bro-
moacetate (1.23 mL, 13.0 mmol). The reaction mixture was
stirred at room temperature for a further 5 h. After that time,
the mixture was poured into water and extracted with EtOAc
(3 × 100 mL). The organic layers were combined, washed with
brine, dried (Na2SO4), and concentrated. The residue was
purified by column chromatography on silica gel with hexane/
ethyl acetate (5:1) to give 8 as a white solid (4.0 g, 96% relative
to 6). 1H NMR (CDCl3) δ 7.97 (d, 2H, J ) 8.4 Hz), 7.65 (d, 2H,
J ) 8.4 Hz), 7.21 (d, 1H, J ) 2.4 Hz), 7.13 (dd, 1H, J ) 8.4, 2.4
Hz), 6.58 (d, 1H, J ) 8.4 Hz), 4.63 (s, 2H), 4.11 (s, 2H), 3.78 (s,
3H), 2.24 (s, 3H), 2.20 (s, 3H); 13C NMR (CDCl3) δ 169.2, 163.0,
156.3, 151.3, 136.8, 136.1, 132.1, 131.2 (q, J ) 32 Hz), 130.6,
128.4, 126.3, 125.8 (q, J ) 4 Hz), 125.3, 122.1, 111.4, 65.4, 52.2,
32.4, 16.1, 14.8; 19F NMR (CDCl3) δ 115.5 (s).
[2-Met h yl-4-[[[4-m et h yl-2-[4-(t r iflu or om et h yl)p h en yl]-
th ia zol-5-yl]m eth yl]su lfa n yl]p h en oxy]a cetic Acid (1). To a
stirred solution of 8 (4.5 g, 9.63 mmol) in 150 mL of THF and
100 mL of H2O at 0 °C was added slowly 6.0 mL (12.0 mmol) of
2.0 M LiOH. The reaction mixture was stirred at 0 °C until TLC
indicated the completion of the reaction (about 1 h), diluted with
water (100 mL), acidified with 0.5 M NaHSO4 (25 mL), and
extracted with a mixed solvent of EtOAc and THF (3:1, 4 × 150
mL). The organic layers were combined, dried (Na2SO4), and
concentrated. The residue was purified by column chromatog-
raphy on silica gel with CH2Cl2/MeOH (10:1) to give 1 as a white
solid (4.3 g, 98%). Mp 133-134 °C dec; 1H NMR (DMSO-d6) δ
8.02 (d, 2H, J ) 8.4 Hz), 7.79 (d, 2H, J ) 8.4 Hz), 7.20 (s, 1H),
7.13 (d, 1H, J ) 8.1 Hz), 6.70 (d, 1H, J ) 8.1 Hz), 4.46 (s, 2H),
Exp er im en ta l Section
Gen er a l Meth od s. All reactions were performed under an
inert atmosphere (Ar or N2) unless otherwise noted. 1H, 13C, and
19F NMR spectra were obtained at 300, 75, and 282 MHz,
respectively. 1H chemical shifts (δ) were reported in ppm with
Me4Si (δ 0.00 ppm) or CHCl3 (δ 7.26 ppm) as internal standards,
13C chemical shifts with CDCl3 (δ 77.0 ppm) or TMS (δ 0.0 ppm)
as internal standards, and 19F chemical shifts with CFCl3 (δ 0.0
ppm) as an external standard. Melting points are uncorrected.
TLC analysis was performed on silica gel sheets containing a
fluorescent indicator. Column chromatography was carried out
on silica gel (35-75 mesh).
2-Meth yl-4-th iocya n a top h en ol (4). To a stirred solution of
o-cresol (3) (10.8 g, 0.10 mmol), sodium thiocyanate (26.0 g, 0.32
mmol), and methanol (70 mL) at 0 °C was added a solution of
sodium bromide (10.3 g, 0.10 mmol) and bromine (5.3 mL, 0.10
mmol) in methanol (100 mL). The mixture was stirred for 3 h
and then diluted with saturated NaHCO3 solution. The mixture
was extracted with CH2Cl2 (3 × 120 mL), and the organic phases
were combined, washed with brine, dried (Na2SO4), and con-
centrated. The residue was purified by column chromatography
on silica gel with hexane/ethyl acetate (4:1) to give 3 as a light
yellow solid (16.0 g, 97%). Mp 70-71 °C (lit.10 mp 70.5-71 °C);
1H NMR (CDCl3) δ 7.33 (d, 1H, J ) 2.4 Hz), 7.26 (dd, 1H, J )
8.4, 2.4 Hz), 6.79 (d, 1H, J ) 8.4 Hz), 6.00 (br s, 1H), 2.23 (s,
3H); 13C NMR (CDCl3) δ 156.3, 135.1, 131.5, 126.9, 116.6, 112.6,
112.5, 15.8.
4-Mer ca p to-2-m eth ylp h en ol (5). A solution of 4 (6.0 g, 36.3
mmol) in anhydrous THF (100 mL) was added cautiously to a
mixture of LiAlH4 (1.4 g, 36.8 mmol) and anhydrous THF (200
mL) at 0 °C. The reaction mixture was stirred at room temper-
ature for 4 h. After that time, unreacted LiAlH4 was destroyed
(10) Fujio, M.; Mishima, M.; Tsuno, Y.; Yukawa, Y.; Takai, Y. Bull.
Chem. Soc. J pn. 1975, 48, 2127.
(11) Hotelling, E. B.; Windgassen, R. J .; Previc, E. P.; Neuworth,
M. B. J . Org. Chem. 1959, 24, 1598.
J . Org. Chem, Vol. 68, No. 23, 2003 9117

4.31 (s, 2H), 2.20 (s, 3H), 2.13 (s, 3H); 13C NMR (DMSO-d6) δ
171.3, 161.6, 156.4, 150.9, 136.4, 134.1, 131.6, 130.7, 129.5 (q,
J ) 32 Hz), 126.7, 126.2, 126.0 (q, J ) 4 Hz), 123.4, 111.9, 66.2,
30.6, 15.9, 14.6; 19F NMR (DMSO-d6) δ 115.5 (s).
Ack n ow led gm en t. We thank Dr. Werner Tu¨ck-
mantel for proofreading the manuscript.
J O035140G
9118 J . Org. Chem., Vol. 68, No. 23, 2003