Synthesis and evaluation of sulfonamide derivatives as potent Human Uric Acid Transporter 1 (hURAT1) inhibitors

Article abstract of DOI:10.1016/j.bmcl.2017.03.041

This letter presents synthesis and structure-activity relationship study of sulfonamide derivatives as inhibitors of Human Uric Acid Transporter 1 (hURAT1). Among all tested sulfonamide derivatives, compounds 9b, 16i and 19b exhibited excellent inhibition activity with IC₅₀ value of 10, 2, and 83?nM, respectively. In addition, compounds 9b and 19b demonstrated moderate PK profile in rats.

Full text of DOI:10.1016/j.bmcl.2017.03.041

Accepted Manuscript
Synthesis and evaluation of sulfonamide derivatives as potent Human Uric Acid
Transporter 1 (hURAT1) inhibitors
Xintuo Yang, Xuehai Pang, Lei Fan, Xinghai Li, Yuanwei Chen
PII:
S0960-894X(17)30277-9
DOI:
http://dx.doi.org/10.1016/j.bmcl.2017.03.041
BMCL 24793
Reference:
Bioorganic & Medicinal Chemistry Letters
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Revised Date:
Accepted Date:
13 December 2016
6 February 2017
16 March 2017
Please cite this article as: Yang, X., Pang, X., Fan, L., Li, X., Chen, Y., Synthesis and evaluation of sulfonamide
derivatives as potent Human Uric Acid Transporter 1 (hURAT1) inhibitors, Bioorganic & Medicinal Chemistry
Letters (2017), doi: http://dx.doi.org/10.1016/j.bmcl.2017.03.041
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Xintuo Yang, Xuehai Pang, Lei Fan, Xinghai Li and Yuanwei Chen

Bioorganic & Medicinal Chemistry Letters
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Synthesis and evaluation of sulfonamide derivatives as potent Human Uric Acid
Transporter 1 (hURAT1) inhibitors
Xintuo Yang a,b, Xuehai Pang a,b, Lei Fan c, Xinghai Li c, and Yuanwei Chen a,b,c,d,∗
a Chengdu Institute of Organic Chemistry, Chinese Academy of Sciences, Chengdu, Sichuan, 610041, China.
b University of Chinese Academy of Sciences, Beijing, 100049, China.
c Hinova Pharmaceuticals Inc., Suite 301, Building B, #5 South KeYuan Road, Chengdu, Sichuan, 610041, China.
d State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, Chengdu, Sichuan, 610041, China.
ARTICLE INFO
ABSTRACT
Article history:
Received
This letter presents synthesis and structure-activity relationship study of sulfonamide derivatives
as inhibitors of Human Uric Acid Transporter 1 (hURAT1). Among all tested sulfonamide
derivatives, compounds 9b, 16i and 19b exhibited excellent inhibition activity with IC50 value of
10, 2, and 83 nM, respectively. In addition, compounds 9b and 19b demonstrated moderate PK
profile in rats.
Revised
Accepted
Available online
2009 Elsevier Ltd. All rights reserved.
Keywords:
hURAT1 inhibitor
Bioisostere
Sulfonamide
Structure-activity relationship
Pharmacokinetic studies
Gout disease
In humans, the final purine metabolism product is urate (uric
acid) and predominately excreted via the kidney; as humans are
uricase deficient, they cannot metabolize urate to the allantoin.1-2
Urate serves as a biologically radical scavenger and antioxidant
in humans, whereas the high levels of urate leads to
hyperuricemia which causes many diseases such as gout,
hypertension, chronic kidney diseases, cardiovascular diseases,
and metabolic syndrome.3-4 In humans, the elevated levels of
serum urate results from the absence of uricase and the presence
of effective renal urate reabsorption.5-6 Therefore, the renal
reabsorption process plays a pivotal role in the elevated levels of
plasma urate. In the process of reabsorption, urate is reabsorbed
from the tubular lumen across the apical membrane into the
proximal tubular cells and then extruded from the cells across the
basolateral membrane into the blood. In the kidneys (i.e.
proximal tubular cells), the Human Uric Acid Transporter 1
(hURAT1, encoded by SLC22A12) is localized at the apical
membrane and recognized as a major transporter protein for urate
reabsorption.7-8 Therefore, inhibition of hURAT1 would be a
very effective way to treat hyperuricemia.
To date, several commercially available drugs inhibiting urate
uptake mediated by hURAT1, including probenecid 1,
benzbromarone 2 and lesinurad 3 have been marketed (Fig. 1).
Benzbromarone 2, a potent hURAT1 inhibitor, was withdrawn
from the market of many countries in 2003 because of acute liver
failure, but it is still available in some European countries, as
well as in several Asian countries and South American
countries.9 Lesinurad 3 is an oral hURAT1 inhibitor developed
by AstraZeneca and approved as combination therapy with a
xanthine oxidase inhibitor, Allopurinol or Febuxostat, for the
treatment of hyperuricemia by the Food and Drug Administration
(FDA) in 2015.10-11
Figure 1. hURAT1 inhibitor drugs
———
∗ Corresponding author. Tel.: +86-2885058465; e-mail: ywchen@scu.edu.cn

Initially, we synthesized the methanesulfonamide compound
9a by following Scheme 1. Bis(pinacolato)diboron reacted with
10 under the catalyst of Pd(dppf)Cl2, which gave compound 11.
Further suzuki coupling of 11 with 4-amino-3-bromopyridine
provided 12, which subsequently reacted with methanesulfonyl
chlorides under the conditions of Et3N in DCM to afford
compound 9a. It was found that methanesulfonamide compound
9a showed the moderate activity with an IC50 value of 261 nM,
which suggested that sulfonamide moiety of compound 9a had
the similar biological activity with the carboxylic portion of
Verinurad 4. Encouraged by the result, further optimization of
the sulfonamide moiety could be performed. Hence, a series of
sulfonamide compounds were synthesized by following Scheme
1 and the IC50 values of them were listed in Table 1.
In recent years, intense efforts to develop hURAT1 inhibitors
are ongoing in pharmaceutical industry and academia, and
different kinds of compounds are emerging. Most of these
compounds have a carboxylic acid group moiety. For example,
carboxylic acid compounds 4 and 5 developed by AstraZeneca
could lower serum urate levels through inhibition of hURAT1
with nanomolar potency (Fig. 2).12-14 In addition, diverse
hURAT1 inhibitors (6-8) from patents and literatures also contain
carboxylic acid moiety (Fig. 2).15-17
Scheme 1. Reagent and conditions: (a) bis(pinacolato)diboron, Pd(dppf)Cl2, KOAc, 1,4-
dioxane, H2O, 100 ; (b) 4-amino-3-bromopyridine, Pd(PPh3)4, Na2CO3, 1,4-dioxane,
H2O, 90 ; (c) R1SO2Cl or Tf2O, DCM, Et3N.
Table 1
Activity of compounds with different sulfonamide moieties.
Figure 2. hURAT1 inhibitors with carboxylic acid moiety.
Due to the lack of structural information of hURAT1, it is
difficult for the structure-based drug design approach to guide the
lead identification effort. It is found that uric acid is a substrate of
organic anion transporters such as hOAT1 and hURAT1, and
predominates in the anionic form in blood and urine.18 Therefore,
it is assumed that a potent hURAT1 inhibitor may need a
negative charge to interact with the positively charged binging
pocket.19-20 The carboxylic acid group in many hURAT1
inhibitors may serve as a negative charge to achieve the
inhibitory activity. It is well known that bioisosterism could be
used as a tool to modify the key compounds into more potent
agents. Replacement of carboxylic acid group with proper
bioisosteres that replace the only hydroxyl portion or the entire
carboxylic group has been utilized widely.21 Hence, we decided
to replace the carboxylic acid of hURAT1 inhibitor 4 with
nonclassical bioisostere sulfonamide to probe its influence on the
inhibition activity (Fig. 3).
compounds
R1
hURAT1 IC50 a (nM)
9a
9b
9c
9d
9e
9f
Me
261
10
CF3
Et
n-Pr
713
1100
597
127
2000
1400
i-Bu
Ph
9g
9h
p-fluorophenyl
p-cyanophenyl
a IC50 values are the means of two determinations.
As shown in Table 1, compound 9b showed excellent
inhibition activity with IC50 value of 10 nM, which was 26-fold
improvement in potency in comparision with the 9a. The phenyl
analogue 9f displayed slightly better activity than 9a. Whereas
other aliphatic alkylsulfonamide compounds 9c, 9d and 9e were
much less effective. It could be explained that the trifluoromethyl,
a strong electron-withdrawing group, made the sulfonamide more
acidic, which helped IC50 value boost from 261 nM of 9a to 10
Figure 3. Sulfonamide replaced the carboxylic acid portion of hURAT1 inhibitor 4.

nM of 9b. Surprisingly, compounds 9g and 9h exhibited lower
inhibition activity than 9f.
16i
16j
16k
H
H
H
H
H
H
CN
CN
CN
CF3
Ph
2
390
4000
Next, we investigated the influence of different aromatic rings
on the inhibition activity. The compounds containing different
aromatic rings were synthesized by following Scheme 2 and the
IC50 values were listed in Table 2. As shown in Table 2, when
R5 was kept as methyl group, it was found that the compounds
showed low inhibition activity when there were substituents on
ortho position of benzene ring such as compounds 16a and 16b.
When the substituents were on the meta position of benzene ring
such as compounds 16c and 16d, it was found that these
compounds exhibited slightly better inhibiton activity. However,
when the substituents were attached to para position of benzene
ring such as 16e and 16f, we found that compound 16f with
nitrile group on para position displayed slightly higher activity
than naphthalene analogue 9a. Surprisingly, when R5 was
changed from the methyl to trifluoromethyl, it was found that
compounds 16g, 16h and 16i, showed much better activity
regardless of aromatic rings. It was noted that compound 16i
exhibited very strong inhibition activity with an IC50 value of 2
nM.
p-fluorophenyl
a IC50 values are the means of two determinations.
Driven by a desire to further demonstrate sulfonamide could
replace the carboxylic acid group and maintain or improve the
inhibition activity of hURAT1. Besides the aryl substituted
pyridine scaffold described above, we also applied the
sulfonamide approach to quinoline, a 2,3-benzopyridine scaffold.
Methanesulfonamide 19a and trifluoromethanesulfonamide 19b
were synthesized as shown in the Scheme 3 and their IC50 values
were listed in Table 3. The IC50 value suggested the compound
19b with an IC50 value of 83 nM was compared favorably with
the reported carboxylic acid compound 7 with an IC50 value of 33
nM.
Scheme 3. Reagent and conditions: (h) acetamide, K2CO3, 180 ; (i) R6SO2Cl or Tf2O,
DCM, Et3N.
Scheme 2. Reagent and conditions: (d) n-BuLi, THF, trimethyl borate, -78 , 2N HCl;
(e) 4-amino-3-bromopyridine, Pd(PPh3)4, Na2CO3, 1,4-dioxane, H2O, 90 ; (f) R5SO2Cl
or Tf2O, DCM, Et3N.
Table 3
Activity of sulfonamide compounds containing quinoline scaffold
Table 2
Activity of sulfonamide compounds with different aromatic rings.
compounds
19a
R6
Me
CF3
hURAT1 IC50 a (nM)
3600
83
19b
a IC50 values are the means of two determination
compounds
R2
R3
R4
R5
hURAT1
IC50 a (nM)
20900
11999
9836
Compounds 9a, 9b, 16i and 19b were tested in male Sprague-
Dawley rats to evaluate their pharmacokinetics and the results
were shown in Table 4. The pharmacokinetic parameters, such as
T1/2 and AUC0-t, were calculated via noncompartmental model
using WinNonlin6.2.1 software program. By oral dose of 10
mg/kg, we found that half-life was improved from 3.2 h (9a) to
16a
16b
16c
16d
16e
16f
OMe
CF3
H
H
H
H
H
Me
Me
Me
Me
Me
Me
CF3
CF3
OMe
F
H
H
H
2827
19.6
h
(9b),
and
body
exposure
(AUC)
of
trifluoromethanesulfonamide 9b was 2-fold improvement in
comparison with methanesulfonamide 9a. However, for the
benzene analogue 16i, half–life was reduced to 4.1 h and body
exposure (AUC) was only 6.4µg·h/ml in comparison with 9b.
The 19b, quinoline as scaffold, not only gave the highest
exposure (AUC, 181µg·h/ml) but also exhibited lowest plasma
H
H
CF3
CN
H
4059
H
H
203
16g
16h
OMe
H
H
241
H
OMe
215

11. Keenan, R. T.; Schlesinger, N. Curr. Rheumatol. Rep. 2016,
18, 32
clearance (T1/2, 19.8 h) among 9a, 9b, 16i and 19b by oral dose
of 10 mg/kg.
12. Miner, J.N.; Tan, P. Ann. Rheum. Dis. 2012, 71(suppl 2),
446.
13. Ouk, S.; Gunic, E.; Vernier, J. US 20130281469.
14. Li-Tain, Y.; Barry D, Q. WO 2013067425.
15. Ouk, S.; Vernier, J.; Gunic, E. WO 2011159840.
16. Peng, J.; Hu, Q.; Gu, C.; Liu, B.; Jin, F.; Yuan, J.; Feng, J.;
Zhang, L.; Lan, J.; Dong, Q.; Cao, Q. Bioorg. Med. Chem.
Lett. 2016, 26, 277
Table 4
Pharmacokinetic properties of compounds 9a, 9b, 16i, and 19b
Parameters
Rat(PO)
Rat(IV)
16i
9a
10
9b
16i
10
19b
10
9a
9b
19b
Dose (mg/kg)
Tmax (h)
10
1
1
1
1
1
17. O’Neil, J.D.; Bamat, M.; Von Borstel, R.; Sharma, S.;
Arudchandran, R. WO 2009151695.
18. Wempe, M.F.; Jutabha, P.; Quade, B.; Iwen, T.J.; Frick,
M.M.; Ross, I.R.; Rice, P.J.; Anzai, N.; Endou, H. J. Med.
Chem. 2011, 54, 2701.
19. Wempe, M. F.; Quade, B.; Jutabha, P.; Iwen, T.; Frick, M.;
Rice,P.J.; Wakui, S.; Endou, H. Nucleos.Nucleot.Nucl. 2011,
30, 1312.
20. Wempe, M.F.; Lightner, J.W.; Miller, B.; Iwen, T.J.; Wakui,
S.; Anzai, N.; Jutabha, P.; Endou, H. Drug. Des. Dev. Ther.
2012, 6, 323.
1
2
5.3
0.9
3.9
5.7
6.5
2.7
2.5
0.4
ND
0.9
10.8
8.1
0.9
4.4
2.6
2.4
1.9
6.8
0.8
ND
0.9
T1/2 (h)
3.2
17.4
38.6
3.3
NDa
ND
59
19.6
9.0
4.1
0.3
6.4
5.2
ND
ND
27
19.8
10.5
181
28.7
ND
ND
28
14
7.7
64
Cmax (µg/ml)
AUC0-t (µg·h/ml)
MRT (h)
72.1
27.2
ND
ND
21.8
33.1
13.8
0.3
19
Cl (ml/min/kg)
Vss (L/kg)
F (%)
0.2
0.2
ND
0.3
21. Meanwell, N.A. J. Med. Chem. 2011, 54, 2529.
ND
a ND: No Data
In summary, we found that the sulfonamide could be utilized
to improve or maintain the hURAT1 inhibition activity by the
bioisosteric replacement of carboxylic group. Especially,
triflourosulfonamide 9b, 16i, and 19b exhibited excellent in vitro
inhibition activity. Through pharmacokinetic studies of
compounds 9a, 9b, 16i and 19b, we found that 9b and 19b
showed moderate pharmacokinetic profile.
Acknowledgment
We thank Kexin Xu, Ke Chen, and Shaohua Zhang of Hinova
Pharmaceuticals Inc who had contributed to this work. We also
thank Dr. Wu Du for suggestions to this work.
Supplementary data
Supplementary data (experimental procedures and biological
measuring methods) associated with this article can be found.
Reference and notes
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2007, 19, 151.
2. Roch-Ramel, F.; Cuisan, B. News. Physiol. Sci. 1999, 14,
80.
3. Becker, B. F. Free. Radical. Bio. Med. 1993, 14, 615.
4. Becker, M. A.; Jolly, M. Rheum. Dis. Clin. North Am. 2006,
32, 275.
5. Maesaka, J. K.; Fishbane, S. Am. J. Kidey. Dis. 1998, 32,
917.
6. Anzai, N. Jutabha, P. Endou, H. Curr. Hypertens. Rev. 2010,
6, 148.
7. Enomoto, A.; Kimura, H.; Chairoungdua, A.; Shigeta, Y.;
Jutabha, P.; Cha, S. H.; Hosoyamada, M.; Takeda, M.;
Sekine, T.; Igarashi, T.; Matsuo, H.; Kikuchi, Y.; Oda, T.;
Ichida, K.; Hosoya, T.; Shimokata, K.; Niwa, T.; Kanai, Y.;
Endou, H. Nature. 2002, 417, 447.
8. Shin, H. J.; Takeda, M.; Enomoto, A.; Fujimura, M.;
Miyazaki, H.; Anzai, N.; Endou, H. Nephrology. 2011, 16,
156
9. Lee, M. H.; Graham, G. G.; Williams, K. M.; Day, R. O.
Drug Safety. 2008, 31, 643.
10. Diza-Torne, C.; Perez-Herrero, N.; Perez-Ruiz, F. Curr.
Opin. Rheumatol. 2015, 27, 164.

Highlights
ꢀ
ꢀ
Sulfonamide showed the hURAT1 inhibition activity.
Structure-activity relationship of sulfonamide as
inhibitors of hURAT1.
ꢀ
Compounds 9b and 19b demonstrated moderate PK
profile in rats.