Discovery of 6′-chloro-N-methyl-5’-(phenylsulfonamido)-[3,3′-bipyridine]-5-carboxamide (CHMFL-PI4K-127) as a novel Plasmodium falciparum PI(4)K inhibitor with potent antimalarial activity against both blood and liver stages of Plasmodium

Article abstract of DOI:10.1016/j.ejmech.2019.112012

Starting from a bipyridine-sulfonamide scaffold, medicinal chemistry optimization leads to the discovery of a novel Plasmodium falciparum PI4K kinase (PfPI4K) inhibitor compound 15g (CHMFL-PI4K-127, IC₅₀: 0.9 nM), which exhibits potent activity against 3D7 Plasmodium falciparum (P. falciparum) (EC₅₀: 25.1 nM). CHMFL-PI4K-127 displays high selectivity against PfPI4K over human lipid and protein kinase. In addition, it exhibits EC₅₀ values of 23–47 nM against a panel of the drug-resistant strains of P. falciparum. In vivo, the inhibitor demonstrates the favorable pharmacokinetic properties in both rats and mice. Furthermore, oral administration of CHMFL-PI4K-127 exhibits the antimalaria efficacy in both blood stage (80 mg/kg) and liver stage (1 mg/kg) of Plasmodium in infected rodent model. The results suggest that CHMFL-PI4K-127 might be a new potential drug candidate for malaria.

Full text of DOI:10.1016/j.ejmech.2019.112012

Journal Pre-proof
Discovery of 6′-chloro-N-methyl-5'-(phenylsulfonamido)-[3,3′-bipyridine]-5-
carboxamide (CHMFL-PI4K-127) as a novel Plasmodium falciparum PI(4)K inhibitor
with potent antimalarial activity against both blood and liver stages of Plasmodium
Xiaofei Liang, Zongru Jiang, Zhenghui Huang, Feng Li, Cheng Chen, Chen Hu,
Wenliang Wang, Zhenquan Hu, Qingwang Liu, Beilei Wang, Li Wang, Ziping Qi, Jing
Liu, Lubin Jiang, Qingsong Liu
PII:
S0223-5234(19)31169-9
DOI:
https://doi.org/10.1016/j.ejmech.2019.112012
EJMECH 112012
Reference:
To appear in: European Journal of Medicinal Chemistry
Received Date: 30 October 2019
Revised Date: 21 December 2019
Accepted Date: 25 December 2019
Please cite this article as: X. Liang, Z. Jiang, Z. Huang, F. Li, C. Chen, C. Hu, W. Wang, Z. Hu, Q. Liu, B.
Wang, L. Wang, Z. Qi, J. Liu, L. Jiang, Q. Liu, Discovery of 6′-chloro-N-methyl-5'-(phenylsulfonamido)-
[3,3′-bipyridine]-5-carboxamide (CHMFL-PI4K-127) as a novel Plasmodium falciparum PI(4)K inhibitor
with potent antimalarial activity against both blood and liver stages of Plasmodium, European Journal of
Medicinal Chemistry (2020), doi: https://doi.org/10.1016/j.ejmech.2019.112012.
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2019 Published by Elsevier Masson SAS.

Discovery of 6'-Chloro-N-methyl-5'-(phenylsulfonamido)-[3,3'-bipyridine]-5-
carboxamide (CHMFL-PI4K-127) as a Novel Plasmodium falciparum PI(4)K
Inhibitor with Potent Antimalarial Activity against both Blood and Liver
Stages of Plasmodium
1
,6
1,2,6
3,6
1,2,6
1,2
1
Xiaofei Liang , Zongru Jiang , Zhenghui Huang , Feng Li , Cheng Chen , Chen Hu ,
1
,2
1
4
1
1,2
1
Wenliang Wang , Zhenquan Hu , Qingwang Liu , Beilei Wang , Li Wang , Ziping Qi , Jing
1
*
3*
1,2,4,5*
Liu , Lubin Jiang , Qingsong Liu
1
. High Magnetic Field Laboratory, Key Laboratory of High Magnetic Field and Ion Beam
Physical Biology, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei,
Anhui, 230031, China
2
3
. University of Science and Technology of China, Hefei, Anhui 230026, P. R. China
. Unit of Human Parasite Molecular and Cell Biology, Key Laboratory of Molecular Virology
and Immunology, Institute Pasteur of Shanghai, University of Chinese Academy of
Sciences, Chinese Academy of Sciences, 200031 Shanghai, P. R. China
. Precision Targeted Therapy Discovery Center, Institute of Technology Innovation, Hefei
Institutes of Physical Science, Chinese Academy of Sciences, Hefei, Anhui 230088, P. R.
China
4
5
6
. Institutes of Physical Science and Information Technology, Anhui University, Hefei, Anhui
2
30601, P. R. China
. These authors contribute equally
AUTHOR INFORMATION
Corresponding Authors

*
*
*
E-mail: qsliu97@hmfl.ac.cn. Phone: 86-551-65595161 (Q.Liu).
E-mail: lbjiang@ips.ac.cn. Phone: 86-21-54923072 (L.Jiang).
E-mail: jingliu@hmfl.ac.cn. Phone: 86-551-65593186 (J.Liu).
ABSTRACT
Starting from a bipyridine-sulfonamide scaffold, medicinal chemistry optimization leads to the
discovery of a novel Plasmodium falciparum PI4K kinase (PfPI4K) inhibitor compound 15g
(
CHMFL-PI4K-127, IC : 0.9 nM), which exhibits potent activity against 3D7 Plasmodium
50
falciparum (P. falciparum) (EC : 25.1 nM). CHMFL-PI4K-127 displays high selectivity against
5
0
PfPI4K over human lipid and protein kinase. In addition, it exhibits EC values of 23-47 nM
50
against a panel of the drug-resistant strains of P. falciparum. In vivo, the inhibitor demonstrates
the favorable pharmacokinetic properties in both rats and mice. Furthermore, oral administration
of CHMFL-PI4K-127 exhibits the antimalaria efficacy in both blood stage (80 mg/kg) and liver
stage (1 mg/kg) of Plasmodium in infected rodent model. The results suggest that CHMFL-
PI4K-127 might be a new potential drug candidate for malaria.
Keywords
PI4K kinase, kinase inhibitor, malaria, blood stage, liver stage
Abbreviations used
P. falciparum, Plasmodium falciparum; P.yoelii, Plasmodium yoelii; PfPI4K, Plasmodium
falciparum
phosphatidylinositol-4-kinase;
PI4K,
phosphatidylinositol-4-kinase;
PI,
phosphatidylinositol; PI4P, phosphtaidylinositol-4-phosphate; ATP, Adenosine Triphosphate;
SAR,
structure-activity
relationship;
DMAP,
4-(Dimethylamino)pyridine;
THF,
Tetrahydrofuran ; TEA, Triethylamine ; DCM, Dichloromethane ;
HATU, 1-

[
Bis(dimethylamino)methylene]-1H-1,2,3-triazolo[4,5-b]pyridinium
hexafluorophosphate; DIPEA, N,N-Diisopropyl-ethylamine; EtOAc, Ethyl acetate.
. Introduction
Drug resistant malaria infections are still a severe threat to the public health[1]. In clinic, there
3-oxid
1
is yet a great demand to seek novel chemotypes with new mechanisms of antimalaria in order to
overcome the drug resistance. In recent years, new chemical entities with activity across different
life cycle stages of the malaria parasite and new mechanisms of action have been identified[2-6].
Plasmodium phosphatidylinositol-4-kinase[3, 6] is one of the attractive drug discovery targets
due to its important roles in all stages of the Plasmodium lifecycle. In addition, it has been
expected that the Plasmodium PI4K inhibitors would overcome the resistance of artemisinin and
artemisinin-based combination therapies for P. falciparum malaria since they bear different
inhibition mechanism[7-10]. Plasmodium PI4K catalyzes the phosphorylation of
phosphatidylinositol (PI) to produce the cellular secondary messenger phosphatidylinositol-4-
phosphate (PI4P), subsequently initiating a cascade of downstream events to modulate a variety
of biological processes including secondary messenger signaling, cellular membrane remodeling,
and vesicular trafficking[11]. A number of Plasmodium PI4K kinase inhibitors with different
chemotypes such as MMV390048 (1)[6], which is now under Phase II clinical trial[12], KAI407
(2)[13], KAI715 (3)[14], KDU731 (4)[15], KDU691 (5)[3], UCT943 (6)[16], BRD73842 (7)[17],
BQR695 (8)[3], and 9[18] have been disclosed in patents and research articles over the past
several years (Figure 1). In this study, we report the discovery of a novel bipyridine-sulfonamide
chemotype PfPI4K inhibitor compound 15g (CHMFL-PI4K-127), which is obtained from
optimizing a chloro-bipyridine chemotype based hit compound 15a (Figure 2).

NC
NC
F3C
N
NH2
N
N
N
N
N
O
O
N
N
N
N
O
S
O
F3C
F3C
1
(MMV390048)
2 (KAI407)
3 (KAI715)
NC
Cl
F3C
N
N
O
NH2
N
N
O
N
N
N
O
N
N
N
H
N
N
H N
2
NH
O
O
4
(KDU731)
5 (KDU691)
6 (UCT943)
H
N
O
HN
MeO
NH
OH
O
N
N
N
N
N
N
N
O
HN
S
H N
2
O
CF3
O
F
MeO
MeO
7
(BRD73842)
8 (BQR695)
9
Figure 1. Chemical structures of representative Plasmodium PI4K inhibitors.
2
. Results and discussion
2
.1 Chemistry
The synthesis of compounds 15a-g was depicted in Scheme 1. The intermediate 12a was
obtained from 10a via N-Boc group protection (11a) and Miyaura borylation reaction. The
pyrrolopyridine 10b was protected with acetyl chloride to give 11b, and then Miyaura borylation
reaction afforded the intermediate 12b. 13 reacted with benzenesulfonyl chloride to provide

sulfonamide 14, which was then converted to compounds 15a-g through Suzuki-Miyaura cross
coupling reaction. As shown in Scheme 2, compounds 18a-k were prepared from intermediate
1
4 through Suzuki-Miyaura cross coupling reaction (16), hydrolysis of the ester (17), and
subsequent standard amide coupling reactions. Suzuki-Miyaura cross coupling reaction of 13
afforded the bipyridine 19, which was then acylated or sulfonated to provide compounds 20a-n
(Scheme 3).
a
Scheme 1. Synthesis of Compounds 15a-g
a
Reagents and conditions: (a) (Boc)
2
O, DMAP, THF, reflux, 14 h; (b) bis(pinacolato)diboron,
PdCl
2
(dppf) , KOAc, dioxane, 80 °C, 10 h; (c) acetyl chloride, TEA, DCM, rt, 14 h; (d)
2

benzenesulfonyl chloride, pyridine, rt, 5 h; (e) for 15a, 15c-g: arylboronic acid or ester,
Pd(PPh ) , KOAc, dioxane, 80 °C, 8 h; for 15b: (i) 12a, Pd(PPh ) , KOAc, dioxane, 80 °C, 8 h;
3
4
3 4
(ii) 4 M HCl in MeOH, MeOH, 2 h.
a
Scheme 2. Synthesis of Compounds 18a-k

a
3 4
Reagents and conditions: (a) arylboronic acid or ester, Pd(PPh ) , KOAc, dioxane, 80 °C, 8 h; (b)
NaOH, MeOH/H O, rt, 12 h; (c) amine, HATU, DIPEA, THF, rt, 14 h.
2
a
Scheme 3. Synthesis of Compounds 20a-n
H
H
N
O
N
O
H N
2
Br
b
a
R
H N
2
N
HN
N
Cl
N
Cl
N
Cl
N
13
19
20a-n
O
O
S
O
O
O
S
O
O
O
S
O
O
Cl
S
R =
C
20a
20b
20c
20d
20e
Cl
F
CF3
O
O
O
S
O
S
O
O
O
O
O
O
S
S
Cl
F
S
20f
20g
20h
20i
20j
F3C
O
S
O
S
O
O
O
O
F3C
O
S
S
O
20k
20l
20m
20n
a
Reagents
and
conditions:
(a)
N-methyl-5-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-
yl)nicotinamide, Pd(PPh ) , K CO , dioxane, 100 ℃, 8 h; (b) acyl chloride or sulfonyl chloride,
3
4
2
3
pyridine, rt, 6 h.
2
.2. Structure-Activity Relationships (SAR) Exploration
The starting hit compound 15a (Figure 2A) was discovered by phenotypic testing against the
D7 P. falciparum blood stage parasite from the in-house generated human kinase small
3
molecule library. 15a displayed the weak antimalarial activity with an EC50 of 3940 nM.
However, 15a exhibited the acticvity against PfPI4K kinase with an IC of 7.7 nM in the
50

biochemical enzymatic assay. This suggested that the potent biochemical PfPI4K activity of
compound 15a was not transformed to the in cell anti-parasite activity. Therefore, the primary
purpose of the hit-to-lead optimization is to keep the PfPI4K kinase inhibitory activity and
meanwhile gain the antiparasite activity in cell. In order to understand the binding mode of
compound 15a, it was docked into the genernted PfPI4K homology model (Figure 2B). After
careful analysis of the molecular modeling results, we found that 15a ocuppied the ATP binding
pocket of PfPI4K kinase. The pyrrolopyridine moiety (“Head” part in Figure 2A) of 15a formed
two hydrogen bonds with Val1357 and Thr1360 in the hinge region (Figure 2B). The
sulfonamide moiety (“Tail” part in Figure 2A) of 15a also formed a hydrogen bond with
conserved residue Lys1308 (Figure 2B). The modeling results indicated that in the “Tail” and
“Head” moiety there were still spaces to be further elaborated by medicinal chemistry. We then
chose to systematically optimize these moietes to obtain a full spectrum of the SAR as illustrated
in Figure 2.

Figure 2. Illustration of the SAR rationale. (A) Structure of compounds 15a-g and 18a-c. (B)
Homology model of PfPI4K with compound 15a illustrating a key interaction in the ATP
binding pocket (PDB: 4DOL). Hydrogen bonds are indicated by green dash line to key amino
acid residues.
The in vitro antimalarial blood-stage activity was tested against P. falciparum using a SYBR
green-based 3D7 P. falciparum assay[19]. Compound 5 (PfPI4K IC : 1.5 nM)[3] was used as
5
0
the positive control in all experiments. The “Head” moiety occupied the hydrophobic pocket
located proximal to the hinge binding region in PfPI4K. Introduction of a nitrogen atom (15b)
did not improve the potency against P. falciparum (Table 1). Addition of an acetyl group (15c)
exhibited potent activity against P. falciparum. Replacing the azaindole by a smaller moiety 3-
pyridine as in 15d let to decrease both the potency against P. falciparum and against PfPI4K. In
addition, replacing the azaindole by 4-pyridine as in 15e resulted in significant activity loss
against both P. falciparum and PfPI4K, suggesting that this nitrogen in 15a is required for potent
antimalarial activity. Interestingly, replacing the azaindole by a smaller moiety N-
methylpyrazole (15f) retained the activity against both P. falciparum and PfPI4K. Unfortunately,
replacement of the azaindole by pyrrole carboxamide (18a) led to significant activity loss against
both P. falciparum and PfPI4K. Based on this primary SAR study, we redesigned the “Head”
moiety in order to improve the potency against both P. falciparum and PfPI4K.
We intitially redesigned compounds 15g, 18b and 18c to explore the relationship between the
hinge binding interations with the “Head” moiety and the antimalarial activity (Table 1). 18b did
not have the hinge binding hydrogen bond acceptor or donor in the phenyl ring of the “Head”
moiety. Therefore, it did not display the activity against both P. falciparum and PfPI4K (Table
1
). Compounds 15g and 18c were introduced a hydrogen bond acceptor nitrogen atom in the

phenyl ring of “Head” moiety. Compound 18c, which has the hydrogen bond acceptor nitrogen
atom in the “Head” moiety similar to 15e, did not display activity against both P. falciparum and
PfPI4K either. 15g with the hydrogen bond acceptor nitogen atom in the “Head” moiety as 15b,
1
5c, 15d and 15f displayed significantly improved activity against both P. falciparum and
PfPI4K. These results suggested that the position of nitrogen atom on the phenyl ring in the
Head” moiety, which formed a hydrogen bond with hinge binding region in PfPI4K kinase, was
“
critical to the efficiency of parasite inhibition. These results correlated well with the analysis
obtained from the docking experiments.
Table 1. In Vitro Blood-Stage Antimalarial Activity and Biochemical Activity against PfPI4K
a
b
Compd.
3D7 (EC : nM)
PfPI4K (IC : nM)
50
5
0
5
41.1
±
1.1
1.6
7.7
5.6
8.1
±
±
±
±
0.0
0.3
1.2
0.3
1
5a
5b
5c
5d
5e
5f
3940
4670
±
±
1850
1
1580
1
1050±
270
1
4710
±
1200
12.7
±
1.5
1
>10000
>156
1
1490
±
±
150
0.1
10.0
0.9
>156
±
0.6
1
5g
8a
25.1
±
0.1
1
＞
10000
1
8b
>10000
>10000
>156
>156
1
8c

a
b
EC50 values are the average of at least three determinations, each carried out in triplicate. IC50
values are the average of at least three determinations, each carried out in triplicate.
On the basis of these results, we then investigated the carboxyamide moiety in compound 15g.
Replacing the methylamine in 15g by larger groups such as ethylamine (18d) and ethyldiamine
(18e) led to 10-fold decrease of the antimalarial activity (Table 2). Notably, more ionizable
1
moieties propanediamine (18f) and dimethylpyrrolidine (18g) in R resulted in significant
antimalarial activity loss. In addition, larger hydrophobic aromatic groups replacement (18h-k)
also resulted in antimalarial activity loss. These results indicated that a bulkier hydrophobic
group was unfavorable at this position.
Table 2. In Vitro Blood-Stage Antimalarial Activity and Biochemical Activity against PfPI4K
1
a
b
Compd.
R
3D7 (EC : nM)
PfPI4K (IC : nM)
5
0
50
1
8d
120±1
130±3
2.3±0.3
13.8±0.8
>40
1
8e
1
8f
>10000
>10000
1
8g
>156

1
8h
3680
>10000
145.1±1.3
>156
O
F
1
8i
N
H
1
8j
>10000
>156
1
8k
3570±2190
8.5±0.3
a
b
EC values are the average of at least three determinations, each carried out in triplicate. IC
50
5
0
values are the average of at least three determinations, each carried out in triplicate.
We next investigated the effect of various fragments in the “Tail” moiety for antimalarial
activities while retaining the “Head” moiety as in 15g (Table 3). Replacing the sulfonamide
moiety in 15g by carboxamide moiety as in 20a led to significant activity loss against both P.
falciparum and PfPI4K, indicating that the sulfonamide group is favorable for forming hydrogen
bonds with PfPI4K kinase. Replacing the benzenesulfonamide moiety in 15g by the smaller and
flexible aliphatic sulfonamide such as 20b and 20c resulted in significantly decreased activities.
These results indicated that the aromatic group was more favorable than aliphatic group to form
the van de Waals interactions with PfPI4K kinase. Replacement of the benzenesulfonamide
moiety in 15g by dihydrobenzofuran sulfonamide as in 20d decreased the antimalarial activity
(EC50: 340 nM vs 25.1 nM). However, the activity was slightly affected when monosubstituted
benzenesulfonamide (20e-f) and disubstituted benzenesulfonamide (20g-h) was introduced. It is
noteworthy that a significant loss of antimalarial potency was observed for the
difluorobenzenesulfonamide as in 20i, but 20i still displayed strong inhibition against PfPI4K
2
kinase. The ortho-trifluoromethyl (20j) and para-trifluoromethyl (20l) in R were observed to

show slight antimalarial activity decrease compared with that of 15g. Unfortunately, the meta-
trifluoromethyl group (20k) led to significant activity loss. Further increase of the substituent
size by attaching a phenyl group at the “Tail” moiety (20m-n) both caused significant activity
loss. It is noteworthy that compounds 20i, 20k, 20m, and 20n did not exhibit strong antimalarial
efficacy though they displayed potent in vitro biochemical PfPI4K inhibitory activity. This
indicated that there might be some cellular penetration or solubility problem with them.
Surprisingly, the biochemically weak inhibitor 20l showed strong antimalarial activity. We
suspected that this compound might bear unknown off-targets for P. falciparum.
Table 3. In Vitro Blood-Stage Antimalarial Activity and Biochemical Activity against PfPI4K
2
a
b
Compd.
R
3D7 (EC : nM)
PfPI4K (IC : nM)
5
0
50
2
0a
>10000
3500
>156
2
0b
52.6±1.2
13.2±2.4
4.5±1.0
2
0c
480±40
340±20
2
0d

2
0e
71±4
39±1
39±5
120±1
3400
87±3
1.6±0.1
1.2±0.2
2.2±0.4
1.2±0.2
0.4±0.0
0.5±0.0
2
0f
20g
2
0h
2
0i
2
0j
2
0k
3500
2.5±0.0
2
0l
130±1
7700
5880
>156
2
0m
7.5±1.0
8.8±0.4
2
0n
a
b
EC values are the average of at least three determinations, each carried out in triplicate. IC
50
5
0
values are the average of at least three determinations, each carried out in triplicate.

To better understand the binding mode of compound 15g, we then docked it into the generated
PfPI4K homology model via molecular modeling (Figure 3A, B). The modeling results
suggested that 15g was accommodated in the ATP-binding pocket (Figure 3A, B). The NH of
nicotinamide group in 15g formed a hydrogen bond with the side chain of Thr1360 in the hinge
region (Figure 3A). The nitrogen atom of nicotinamide group in 15g also formed a hydrogen
bond with the backbone of Val1357 in the hinge region (Figure 3A). The sulfonamide moiety
formed a hydrogen bond with conserved residue Lys1308 (Figure 3A). The chloropyridine
moiety pointed to the hydrophobic pocket, which was formed by the side chains of residues
Ile1354, Leu1313 and Glu1316, and interacted through the van der Waals interactions (Figure
3
B). The edge of pyridine in chloropyridine moiety was adjacent to the side chain of Tyr1342. It
was possible to form edge to face interactions[20] (Figure 3B). Base on the binding mode
analysis, the side chains of Tyr1342 and Thr1360 played important roles in the interactions with
compound 15g. We then generated the PI4K Y1342I and PI4K Y1342I-T1360A mutant kinase
P. falciparum strains from wild type 3D7 P. falciparum by CRISPR/Cas9 system (Figure 3C).
1
5g was 2-fold more potent against mutant P. falciparum PI4K Y1342I strain than wild type 3D7
P. falciparum, indicating that the interactions between the chloropyridine moiety in 15g and the
side chain of Tyr1342 were unfavorable. In addition, 15g displayed 24-fold less activity against
P. falciparum PI4K Y1342I-T1360A strain than P. falciparum PI4K Y1342I strain, indicating
that the hydrogen bond interaction between the side chain of Thr1360 and the NH of
nicotinamide group in 15g was necessary.

Figure 3. (A, B) 15g was docked into the homology model of PfPI4K (PDB:4DOL). PfPI4K
kinase was displayed in white. 15g was labeled in color by atoms (carbon in yellow, nitrogen in
blue, oxygen in red, and chlorine in green). The hydrogen bonds were labeled as green dashed
lines. The key amino acid residues for the interactions were labeled as follows: carbon in green,
nitrogen in blue, and oxygen in red. (C) In vitro blood-stage antimalarial activity against P.
falciparum PI4K mutant strains of 15g.
2
.3. Selectivity of Compound 15g between Human Kinases and PfPI4K
The ADP-glo biochemical assay with purified enzymes of human lipid kinase PI3Ks and
PI4Ks demonstrated that 15g exhibited over 100-fold selectivity against PI3Kα, PI3Kδ, PI3Kγ
and PI4KIIIA (Table 4). 15g also exhibited over 400-fold selectivity against PI3Kβ, VPS34 and
PI4KIIIB. In addition, 15g did not show apparent activity against PIK3C2A and PIK3C2B. To

further characterize the kinome-wide selectivity profile of 15g in the human kinases, we next
performed a selectivity analysis of 15g using DiscoveRx’s KINOMEscan technology[21]. 15g
exhibited high selectivity among 468 kinases/mutants tested with a S score (1) =0
(Supplementary Table 1). This indicated that the antimalarial activity of 15g derives from the
inhibition of P. falciparum target kinase and meanwhile 15g exhibited good selectivity over
kinases of human host.
a
Table 4. Selectivity of Compound 15g against PI3Ks, PI4Ks and PfPI4K (IC : nM)
5
0
Compd. 15g
Compd. 5
PI3K
α
β
191
392
±
36
27
>10000
PI3K
±
2728
3096
5917
±
32
PI3K
δ
104
324
±
3
±
117
PI3K
γ
±19
±32
PIK3C2A
PIK3C2B
VPS34
>10000
>10000
>10000
>10000
681
165
433
±
±
±
25
29
18
9199
1416
±
382
100
PI4KIIIA
PI4KIIIB
±
>10000
1.6±0.0
PfPI4K
0.9±0.1
a
IC50 values were obtained by triplet testings.
2
.4. Activity of Compound 15g against Drug Resistant Strains of P. falciparum
We then evaluated compound 15g against the multidrug-resistant strains of P. falciparum
Dd2, 803, 6320, GB4, FAB9, C2A, D10, PC26, and CP286) using the SYBR green assay. As
(

shown in Table 5, all the tested resistant strains of P. falciparum showed sensitivity towards 15g.
In addition, 15g displayed slightly better activity against the drug resistant strains than 5.
Table 5. Activity of Compound 15g against the Drug-resistant Strains of P. falciparum (EC :
5
0
a
nM)
P. falciparum strains
D7
Dd2
03
320
Drug resistance
SFX
15g
25.1
5
3
±
±
±
±
±
±
±
±
±
±
0.1
0.2
3.3
0.2
5.0
4.8
4.0
3.0
2.2
0.5
41.1
46.7
41.8
33.6
±
±
±
±
1.1
MEF, CQ, PYR
ART
30.3
30.9
24.7
47.8
23.6
28.0
28.0
44.0
24.1
2.5
8
0.5
6
ART, PPQ
unknown
CQ
5.7
GB4
FAB9
C2A
39.2
44.8
±
±
16.5
12.3
PYR, CQ
CQ
33.7
43.9
54.9
31.9
±
0.3
1.2
2.1
2.9
D10
±
±
±
PC26
CP286
PYR, CQ
PYR, CQ
a
EC50 values were obtained by triplet testings. SFX, sulphadoxine. CQ, chloroquine; MEF,
mefloquine; PYR, pyrimethamine; PPQ, piperaquine phosphate; ART, artmisinin.
2
.5. Pharmacokinetic Properties in Rats and Mice of Compound 15g
The pharmacokinetic properties of compound 15g were evaluated in Sprague-Dawley rats and
mice following intravenous and oral administration (Table 6). 15g exhibited a fast absorption,
large volume of distribution, and favorable oral bioavailability (F = 89%) when dosed orally in
rats. It also displayed a proper T1/2 of 2.9 h in rats. In addition, 15g exhibited similar

pharmacokinetic properties in mice when dosed orally. This indicated that 15g would be suitable
for oral administration for in vivo study.
Table 6. In Vivo Pharmacokinetic Properties of Compound 15g in Rats and Mice through
a
Intravenous and Oral Administration
Rats
Mice
PO (10 mg/kg)
IV (1 mg/kg)
PO (10 mg/kg)
19266.4±1944.1
19331.7±1956.9
4.3±0.7
IV (1 mg/kg)
327.4 ±71.1
291.6±32.2
3.1±1.9
AUC0-t
ng/mL*h)
AUC0-∞
2
162.9±766.8
168.0±763.1
1.0±0.6
2631.0±490.0
2382.0±420.0
4.4±1.0
(
(
2
ng/mL*h)
MRT(0-t) (h)
Cmax (ng/mL)
Vz (L/kg)
5010.5±105.9
2.6±0.2
0.5±0.1
0.02±0.0
3.5±2.8
-
4335.8±1142.5
2.2±0.3
718.3±91.8
12.1±2.9
3.1±0.6
1539.0±957.0
20.2 ±4.9
3.9±0.8
CLz (L/h/kg)
0.5±0.1
T
max (h)
0.83±0.29
2.9±0.3
0.03±0.0
2.7 ±0.2
-
0.19±0.10
3.6±0.9
T1/2 (h)
F
89%
80%
a
All testing data were obtained from three independent mice (±SD).
2
.6. In Vivo Blood-Stage and Liver-Stage Efficacy of Compound 15g in Rodent Malaria Model
In vivo blood-stage efficacy studies of compound 15g on a murine P. yoelii model[22-24]
(Balb/c) were then investigated. In these in vivo experiments, the Balb/c mice were infected by P.
yoelii. After 24 h, oral administration of 15g were started in mice using fixed doses of 60 and 80
mg/kg/day for consecutive 7 days. 15g displayed significant in vivo antimalarial activities in a
dose-dependent manner and 80 mg/kg ×7 days treatment generated curative effects (Figure 4).

The 60 mg/kg dosage resulted in suppressive effects during the drug treatment but relapsed after
stopping treatment.
The investigation of in vivo liver-stage efficacy of 15g was conducted with a real-time in vivo
imaging system utilizing a transgenic bioluminescent parasite[25-27] (Figure 5). Mice were
treated once by oral administration of 15g at 1 mg/kg, 5 mg/kg and 15 mg/kg respectively at 2 h
before inoculated with 5000 luciferase-expressing P. berghei sporozoites intravenously through
the tail vein. The mice underwent imaging for luciferase activity at 24, 48, 72, 96, 144, and 196 h
after the infection for liver-stage development and at 72 h for blood-stage infection. Strong
bioluminescence signals were detected in untreated mice at both 24 and 48 h in the area
overlying the liver, followed by an intense signal in the whole body of mice at 72 h, resulting
from infection in the peripheral blood circulation. 15g provided the full protection and cure at 1
mg/kg with no negligible parasite visible in the liver of all tested mice at 24, 48, 72, 96, 144 and
1
96 h, indicating true causal prophylactic efficacy. Notably, all treated mice were cured with no
blood-stage parasites up to day 8.

Figure 4. Efficacies of compound 15g in the in vivo blood-stage on a murine P. yoelii model.
Dosing was started on day 1 after infection.
Figure 5. Efficacies of compound 15g in liver-stage on mice infected with luciferase-expressing
P. berghei sporozoites. Mice were given a single oral dose of 1 mg/kg, 5 mg/kg, and 15 mg/kg of
1
3
5g at 2 h before sporozoite infection.
. Conclusions

In summary, we have discovered a novel chemotype based PfPI4K kinase inhibitor compound
5g, which exhibited potent enzyme and parasite inhibitory activities. In addition, it displayed
1
highly selectivity over human lipid and protein kinases which indicated better therapeutic safety
window. 15g also showed activity across a panel of clinical drug-resistant isolates and therefore
might have a low risk for pre-existing cross-resistance. In the blood-stage malaria model, 15g
resulted in 100% elimination in parasitemia at 80 mg/kg. In the liver-stage malaria model, 15g
also provided full protection and cure at 1 mg/kg. The overall profiles of 15g suggested that it
might be potentially good drug candidate for the treatment of malaria, and further investigation is
in progress.
4
. Experimental section
4
.1. Chemistry.
All reagents and solvents were purchased from commercial sources and were used as received
unless specified otherwise, or prepared as described in the literature. All moisture sensitive
reactions were carried out using dry solvents under ultrapure argon protection. Glassware was
dried in an oven at 140 °C for at least 12 h prior to use and then assembled quickly while hot,
sealed with rubber septa, and allowed to cool under a stream of argon. Reactions were stirred
magnetically using Teflon-coated magnetic stirring bars. Commercially available disposable
syringes were used for transferring the reagents and solvents. HPLC-MS were performed on an
Agilent 6224 TOF using an ESI source coupled to an Agilent 1260 Infinity HPLC system
operating in reverse mode with an Agilent XDB-C18 column (4.6 × 50 mm, 1.8
µm) using a
1
water/acetonitrile (each with 0.2% (v/v) formic acid) gradient at a flow rate at 0.4 mL/min. H
1
3
and C spectra were recorded with a Bruker 500 MHz NMR spectrometer and referenced to
deuterated methanol (CD OD), deuterated dimethyl sulfoxide (DMSO-d ) or deuterated
3
6

chloroform (CDCl
3
). Chemical shifts are expressed in ppm. In the NMR tabulation, s indicates
singlet; d, doublet; t, triplet; q, quartet and m, multiplet. Flash column chromatography was
conducted using silica gel (Silicycle40−64
determined to be above 95 % by HPLC.
µm). The purities of all final compounds were
4
.1.1. tert-Butyl 5-bromo-1H-pyrazolo[3,4-b]pyridine-1-carboxylate (11a). To a solution of 10a
(
770 mg, 3.88 mmol, 1.0 equiv) in THF (10 mL) was added (Boc) O (930 mg, 4.3 mmol, 1.1
2
equiv) and DMAP (10 mg, 0.08 mmol, 0.02 equiv ) at room temperature under argon. Then the
reaction mixture was heated to reflux for 14h. The resulting mixture was concentrated to crude
product, which was purified by flash chromatography (eluting with MeOH in DCM 0-10 %) to
1
give 11a as a white solid (783 mg, 68%). H NMR (500 MHz, DMSO-d )
δ 8.80 (d, J = 2.3 Hz,
6
1
3
1
1
2
4
2
H), 8.63 (d, J = 2.3 Hz, 1H), 8.44 (s, 1H), 1.66 (s, 9H). C NMR (126 MHz, DMSO-d ) δ
6
51.15, 149.47, 137.89, 133.63, 132.47, 119.71, 115.24, 85.06, 28.06. LC-MS (ESI, m/z):
+
98.0227 [M+H] .
.1.2. 1-(5-Bromo-1H-pyrrolo[2,3-b]pyridin-1-yl)ethan-1-one (11b). To a solution of 10b (5 g,
5.4 mmol, 1.0 equiv) in DCM (80 mL) was added TEA (3.6 mL, 30.5 mmol, 1.2 equiv) at 0 °C
under argon. Then a solution of acetyl chloride (2.1 mL, 30.5 mmol, 1.2 equiv) in DCM (5 mL)
was slowly added. The reaction mixture was stirred at room temperature for 14 h. The resulting
mixture was diluted with DCM (100 mL), washed with water (2×50 mL), brine (50 mL) and
dried over anhydrous MgSO . Evaporation of the solvent provided the crude product, which was
4
purified by flash chromatography (eluting with EtOAc in hexance 0-5 %) to give 11b as a white
1
solid (4.1 g, 68%). H NMR (500 MHz, DMSO-d )
δ 8.45 (d, J = 2.2 Hz, 1H), 8.31 (d, J = 2.3
6
1
3
Hz, 1H), 8.02 (d, J = 4.1 Hz, 1H), 6.74 (d, J = 4.1 Hz, 1H), 2.93 (s, 3H). C NMR (126 MHz,

DMSO-d
6
)
δ
168.53, 146.04, 144.34, 132.32, 127.50, 125.60, 114.76, 105.74, 25.89. LC-MS
+
(
ESI, m/z): 238.9835 [M+H] .
4
4
1
.1.3. Compound 12b was prepared following the synthetic procedure of 12a.
.1.3.1. tert-Butyl 5-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrazolo[3,4-b]pyridine-
-carboxylate (12a). To a solution of 11a (2.5 g, 8.4 mmol, 1.0 equiv) in anhydrous dioxane (80
mL) was added bis(pinacolato)diboron (4.2 g, 21.0 mmol, 2.0 equiv), PdCl (dppf) (201 mg, 0.25
2
2
mmol, 0.03 equiv) and KOAc (2.5 g, 25.2 mmol, 3.0 equiv) at room temperature under argon.
Then the reaction mixture was heated to 80°C for 10 h. The resulting mixture was concentrated
to afford the crude product, which was purified by flash chromatography (eluting with EtOAc in
1
hexance 0-10 %) to give 12a as a white solid (2.2 g, 75%). H NMR (500 MHz, DMSO-d )
δ
6
1
3
8
.87 (d, J = 1.6 Hz, 1H), 8.61 (d, J = 1.6 Hz, 1H), 8.47 (s, 1H), 1.35 (s, 12H), 1.18 (s, 9H). C
NMR (126 MHz, DMSO-d6)
δ
155.55, 152.99, 147.48, 139.03, 138.38, 117.80, 84.59, 81.70,
+
2
8.09, 25.10. LC-MS (ESI, m/z): 346.1921 [M+H] .
4
.1.3.2.
1-(5-(4,4,5,5-Tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrrolo[2,3-b]pyridin-1-
1
yl)ethan-1-one (12b). Yield=78% H NMR (500 MHz, DMSO-d
6
)
δ
8.59 (d, J = 1.5 Hz, 1H),
8
1
1
4
1
.32 (d, J = 1.6 Hz, 1H), 7.98 (t, J = 16.4 Hz, 1H), 6.80 (t, J = 6.1 Hz, 1H), 2.99 (s, 3H), 1.34 (s,
1
3
2H). C NMR (126 MHz, DMSO-d )
δ
168.85, 149.69, 149.27, 136.54, 126.02, 123.45,
6
+
06.60, 84.43, 83.27, 26.11, 25.28. LC-MS (ESI, m/z): 287.1574 [M+H] .
.1.4. N-(5-Bromo-2-chloropyridin-3-yl)benzenesulfonamide (14). To a solution of 13 (3.0 g,
4.52 mmol, 1.0 equiv) in anhydrous pyridine (30 mL) was added benzensulfonyl chloride (2.8
g, 15.98 mmol, 1.1 equiv) at room temperature under argon. The reaction mixture was stirred at
room temperature for 5 h. Then the resulting mixture was diluted with water. The precipitate was
1
filtered and dried to give 14 as an off-white solid (3.7 g, 75%). H NMR (500 MHz, DMSO-d
6
)
δ

1
0.63 (s, 1H), 8.42 (d, J = 2.3 Hz, 1H), 7.93 (d, J = 2.3 Hz, 1H), 7.81 – 7.76 (m, 2H), 7.72 – 7.68
1
3
(
m, 1H), 7.65 – 7.58 (m, 2H). C NMR (126 MHz, DMSO-d )
δ
147.61, 144.86, 140.16, 137.79,
6
+
1
4
4
33.90, 132.40, 129.95, 127.08, 118.90. LC-MS (ESI, m/z): 346.9235 [M+H] .
.1.5. Compounds 15b-g were prepared following the synthetic procedure of 15a
.
.1.5.1. N-(2-Chloro-5-(1H-pyrrolo[2,3-b]pyridin-5-yl)pyridin-3-yl)benzenesulfonamide (15a).
To a solution of 14 (150 mg, 0.43 mmol, 1.0 equiv) in dioxane (5 mL) was added (1H-
pyrrolo[2,3-b]pyridin-5-yl)boronic acid (76 mg, 0.47 mmol, 1.1 equiv) at room temperature
3 4
under argon. Then KOAc (128 mg, 1.3 mmol, 3.0 equiv) and Pd(PPh ) (46 mg, 0.04 mmol, 0.1
equiv) were added. The reaction mixture was degassed by argon, and then heated to 80 °C for 8
h. The resulting mixture was concentrated to dryness. The residue was diluted with water (30
mL) and extracted with EtOAc (3×30 mL). The combined organic layers were washed with
water (50 mL), brine (50 mL) and dried over anhydrous Na SO . Evaporation of the solvent
2
4
provided the crude product, which was purified by flash chromatography (eluting with MeOH in
1
DCM 0-5%) to give compound 15a as a white solid (97 mg, 59%). H NMR (500 MHz, DMSO-
d
2
6
1
1
4
6
)
δ
11.89 (s, 1H), 10.46 (s, 1H), 8.62 (d, J = 2.3 Hz, 1H), 8.25 (d, J = 1.0 Hz, 1H), 8.23 (d, J =
.0 Hz, 1H), 7.97 (d, J = 2.3 Hz, 1H), 7.83 – 7.80 (m, 2H), 7.70 (t, J = 7.4 Hz, 1H), 7.62 (t, J =
1
3
.8 Hz, 2H), 7.51 – 7.48 (m, 1H), 6.50 (d, J = 2.0 Hz, 1H). C NMR (126 MHz, DMSO-d )
δ
6
50.42, 148.96, 148.66, 144.87, 144.64, 141.64, 140.60, 135.29, 133.64, 129.85, 128.04, 127.20,
+
26.98, 126.70, 100.99. LC-MS (ESI, m/z): 385.0533 [M + H] .
.1.5.2. N-(2-Chloro-5-(1H-pyrazolo[3,4-b]pyridin-5-yl)pyridin-3-yl)benzenesulfonamide (15b).
Step 1: Followed the synthetic procedure of 15a; Step 2: To a solution of the intermediate in
MeOH (1 mL) was added 1 mL of HCl (4 M in MeOH) at room temperature. The reaction
mixture was stirred at room temperature for 2 h. The resulting mixture was concentrated to give

the crude product, which was purified by flash chromatography (eluting with MeOH in DCM 0-
1
1
0%) as a yellow solid (two steps, 53%). H NMR (500 MHz, DMSO-d )
δ
13.87 (s, 1H), 10.49
6
(s, 1H), 8.80 (s, 1H), 8.65 (s, 1H), 8.54 (s, 1H), 8.28 (s, 1H), 8.05 (s, 1H), 7.79 (d, J = 7.1 Hz,
1
3
2
1
1
4
H), 7.69 (d, J = 6.3 Hz, 1H), 7.61 (d, J = 6.7 Hz, 2H). C NMR (126 MHz, DMSO-d6) δ
52.04, 148.21, 145.53, 145.31, 140.39, 134.57, 134.38, 134.25, 133.78, 131.20, 129.90, 129.03,
+
27.21, 124.73, 114.98. LC-MS (ESI, m/z): 386.0460 [M+H] .
.1.5.3. N-(5-(1-Acetyl-1H-pyrrolo[2,3-b]pyridin-5-yl)-2-chloropyridin-3-yl)benzenesulfonamide
1
(
15c). Yield=59%. H NMR (500 MHz, DMSO-d
6
)
δ
9.01 (d, J = 2.3 Hz, 1H), 8.72 (d, J = 2.2
Hz, 1H), 8.53 (d, J = 2.3 Hz, 1H), 8.49 – 8.47 (m, 1H), 8.14 – 8.08 (m, 2H), 7.83 – 7.79 (m, 2H),
7
1
1
1
4
.74 – 7.70 (m, 2H), 6.58 (dd, J = 3.5, 1.9 Hz, 1H), 1.99 (s, 3H). 129.64 (d, J = 16.7 Hz), 128.10,
1
3
27.50, 127.21, 120.20, 100.92, 24.89. C NMR (126 MHz, DMSO-d6)
δ 169.49, 142.16,
41.66, 139.43, 138.86, 136.37, 135.09, 131.52, 129.88, 129.70, 129.57, 128.10, 127.50, 127.21,
+
22.77, 120.20, 100.92, 24.89. LC-MS (ESI, m/z): 427.0651[M+H] .
1
.1.5.4. N-(6-Chloro-[3,3'-bipyridin]-5-yl)benzenesulfonamide (15d). Yield=61%. H NMR (500
MHz, DMSO-d
6
)
δ
8.90 (d, J = 1.8 Hz, 1H), 8.71 – 8.64 (m, 2H), 8.11 (ddd, J = 8.0, 2.4, 1.6 Hz,
1
7
1
3
4
H), 8.04 (d, J = 2.3 Hz, 1H), 7.82 – 7.78 (m, 2H), 7.73 – 7.68 (m, 1H), 7.64 – 7.61 (m, 2H),
1
3
.58 – 7.56 (m, 1H). C NMR (126 MHz, DMSO-d6)
δ 150.16, 148.13, 146.02, 145.35, 140.41,
35.05, 134.32, 133.74, 133.27, 129.88, 129.39, 127.19, 126.06, 124.58. LC-MS (ESI, m/z):
+
46.0431[M+H] .
1
.1.5.5. N-(6-Chloro-[3,4'-bipyridin]-5-yl)benzenesulfonamide (15e). Yield=58%. H NMR (500
MHz, DMSO-d6)
δ 8.75 – 8.69 (m, 3H), 8.09 (d, J = 2.3 Hz, 1H), 7.78 (dt, J = 8.6, 1.6 Hz, 2H),
1
3
7
.73 (dd, J = 4.5, 1.7 Hz, 2H), 7.71 – 7.67 (m, 1H), 7.62 – 7.58 (m, 2H). C NMR (126 MHz,

DMSO-d
6
)
δ
150.94, 146.85, 145.43, 142.80, 140.38, 134.25, 133.78, 133.35, 131.56, 129.90,
+
1
27.16, 121.83. LC-MS (ESI, m/z): 386.0445[M+H] .
4
.1.5.6.
N-(2-Chloro-5-(1-methyl-1H-pyrazol-4-yl)pyridin-3-yl)benzenesulfonamide
(15f).
1
Yield=50%. H NMR (500 MHz, DMSO-d )
δ 10.35 (s, 1H), 8.51 (t, J = 3.2 Hz, 1H), 8.29 (s,
6
1
7
1
3
4
H), 7.92 (s, 1H), 7.88 (d, J = 2.3 Hz, 1H), 7.78 (dt, J = 8.6, 1.7 Hz, 2H), 7.71 – 7.66 (m, 1H),
13
.62 – 7.58 (m, 2H), 3.90 (s, 3H). C NMR (126 MHz, DMSO-d )
δ 143.61, 143.23, 140.43,
6
36.88, 133.68, 132.11, 131.15, 129.82, 129.26, 127.19, 117.13, 39.26. LC-MS (ESI, m/z):
+
49.0547 [M+H] .
.1.5.7. 6'-Chloro-N-methyl-5'-(phenylsulfonamido)-[3,3'-bipyridine]-5-carboxamide
(15g).
1
Yield=76%. H NMR (500 MHz, DMSO-d )
δ 10.54 (s, 1H), 9.10 – 9.00 (m, 2H), 8.81 (dd, J =
6
8
.8, 4.2 Hz, 1H), 8.73 (t, J = 4.6 Hz, 1H), 8.48 (t, J = 2.1 Hz, 1H), 8.17 (d, J = 2.3 Hz, 1H), 7.80
dd, J = 8.3, 1.1 Hz, 2H), 7.72 (ddt, J = 8.6, 7.0, 1.3 Hz, 1H), 7.61 (dd, J = 10.6, 4.8 Hz, 2H),
(
1
3
2
1
.90 (t, J = 5.6 Hz, 3H). C NMR (126 MHz, DMSO-d ) δ 165.25, 150.13, 148.85, 146.47,
6
45.62, 140.36, 134.95, 133.76, 133.53, 132.77, 131.37, 130.91, 130.57, 129.86, 127.18, 26.69.
+
LC-MS (ESI, m/z): 403.0675 [M+H] .
4
4
.1.6. Compounds 16b-d were prepared following the synthetic procedure of 16a
.
.1.6.1. Methyl 4-(6-chloro-5-(phenylsulfonamido)pyridin-3-yl)-1H-pyrrole-2-carboxylate (16a).
To a solution of 14 (150 mg, 0.43 mmol, 1.0 equiv) in dioxane (5 mL) was added methyl 4-
4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrrole-2-carboxylate (122 mg, 0.47 mmol, 1.1
(
equiv) at room temperature under argon. Then KOAc (128 mg, 1.3 mmol, 3.0 equiv) and
Pd(PPh ) (46 mg, 0.04 mmol, 0.1 equiv) were added. The reaction mixture was degassed by
3
4
argon and then heated to 80 °C for 8 h. The resulting mixture was concentrated to dryness. The
residue was diluted with water (30 mL) and extracted with EtOAc (3×30 mL). The combined

organic layers were washed with water (50 mL), brine (50 mL) and dried over anhydrous
Na SO . Evaporation of the solvent provided the crude product, which was purified by flash
2
4
chromatography (eluting with MeOH in DCM 0-5 %) to give 16a as a white solid (102 mg,
1
6
7
1
1%). H NMR (500 MHz, DMSO-d )
δ
12.32 (s, 1H), 10.29 (s, 1H), 8.56 (d, J = 2.3 Hz, 1H),
6
.88 (d, J = 2.3 Hz, 1H), 7.74 (dd, J = 5.2, 3.3 Hz, 2H), 7.70 – 7.66 (m, 1H), 7.63 (dd, J = 3.1,
1
3
.8 Hz, 1H), 7.58 (dd, J = 10.6, 4.8 Hz, 2H), 7.27 – 7.15 (m, 1H), 3.81 (s, 3H). C NMR (126
MHz, DMSO-d
6
)
δ
161.03, 143.71, 143.25, 140.55, 133.61, 132.20, 131.08, 131.01, 129.80,
+
1
27.15, 123.88, 122.83, 120.21, 112.67, 51.79. LC-MS (ESI, m/z): 392.0462 [M+H] .
1
4
.1.6.2. Ethyl 3-(6-chloro-5-(phenylsulfonamido)pyridin-3-yl)benzoate (16b). Yield=74%. H
10.49 (s, 1H), 8.62 (d, J = 2.3 Hz, 1H), 8.12 (t, J = 1.6 Hz, 1H),
.04 – 8.02 (m, 1H), 7.95 (d, J = 2.3 Hz, 1H), 7.82 – 7.78 (m, 2H), 7.69 (dt, J = 14.1, 4.8 Hz,
NMR (500 MHz, DMSO-d6)
δ
8
2
1
3
H), 7.64 – 7.60 (m, 3H), 4.41 – 4.36 (m, 2H), 1.39 – 1.35 (m, 3H). C NMR (126 MHz,
165.78, 145.70, 145.23, 140.34, 136.05, 135.10, 133.97, 133.78, 132.13, 131.42,
31.35, 130.31, 129.89, 129.78, 127.73, 127.18, 61.51, 14.62. LC-MS (ESI, m/z): 417.0654
DMSO-d6)
δ
1
+
[
M+H] .
4
.1.6.3.
Methyl
6-chloro-5-(phenylsulfonamido)-[3,4'-bipyridine]-2'-carboxylate
(16c).
1
Yield=65%. H NMR (500 MHz, DMSO-d )
δ
10.57 (s, 1H), 8.85 (dd, J = 5.0, 0.5 Hz, 1H), 8.78
6
(t, J = 1.8 Hz, 1H), 8.73 (dt, J = 11.8, 5.9 Hz, 2H), 8.01 (dd, J = 5.1, 1.9 Hz, 1H), 7.80 (dt, J =
3
4
4
.2, 2.4 Hz, 2H), 7.74 – 7.69 (m, 1H), 7.64 – 7.59 (m, 2H), 3.91 (s, 3H). LC-MS (ESI, m/z):
+
04.0490 [M+H] .
.1.6.4.
Ethyl
6'-chloro-5'-(phenylsulfonamido)-[3,3'-bipyridine]-5-carboxylate
(16d).
1
Yield=58%. H NMR (500 MHz, DMSO-d
6
)
δ
10.52 (s, 1H), 9.14 (dd, J = 10.9, 2.1 Hz, 2H),
8
.70 (d, J = 2.3 Hz, 1H), 8.46 (t, J = 2.1 Hz, 1H), 8.05 (d, J = 2.3 Hz, 1H), 7.79 – 7.75 (m, 2H),