3,5-Disubstituted-indole-7-carboxamides as IKKβ Inhibitors: Optimization of Oral Activity via the C3 Substituent

Article abstract of DOI:10.1021/acsmedchemlett.8b00291

IκB kinase β (IKKβ or IKK2) is a key regulator of nuclear factor kappa B (NF-κB) and has received attention as a therapeutic target. Herein we report on the optimization of a series of 3,5-disubstituted-indole-7-carboxamides for oral activity. In doing so

Full text of DOI:10.1021/acsmedchemlett.8b00291

Subscriber access provided by RMIT University Library
Letter
3,5-Disubstituted-indole-7-carboxamides as IKK inhibitors:
Optimization of Oral Activity via the C3 Substituent
Jeffrey K Kerns, Jakob Busch-Petersen, Wei Fu, Jeffrey C Boehm, Hong Nie, Michael Muratore,
Ann Bullion, Guoliang Lin, Huijie Li, Roderick S Davis, Xichen Lin, Ami S. Lakdawala, Rick
Cousins, Rita Field, Jeremy Payne, David D Miller, Paul Bamborough, John A. Christopher,
Ian Baldwin, Ruth R Osborn, John G. Yonchuk, Edward Webb, and William L Rumsey
ACS Med. Chem. Lett., Just Accepted Manuscript • DOI: 10.1021/acsmedchemlett.8b00291 • Publication Date (Web): 30 Oct 2018
Downloaded from http://pubs.acs.org on October 30, 2018
Just Accepted
“Just Accepted” manuscripts have been peer-reviewed and accepted for publication. They are posted
online prior to technical editing, formatting for publication and author proofing. The American Chemical
Society provides “Just Accepted” as a service to the research community to expedite the dissemination
of scientific material as soon as possible after acceptance. “Just Accepted” manuscripts appear in
full in PDF format accompanied by an HTML abstract. “Just Accepted” manuscripts have been fully
peer reviewed, but should not be considered the official version of record. They are citable by the
Digital Object Identifier (DOI®). “Just Accepted” is an optional service offered to authors. Therefore,
the “Just Accepted” Web site may not include all articles that will be published in the journal. After
a manuscript is technically edited and formatted, it will be removed from the “Just Accepted” Web
site and published as an ASAP article. Note that technical editing may introduce minor changes
to the manuscript text and/or graphics which could affect content, and all legal disclaimers and
ethical guidelines that apply to the journal pertain. ACS cannot be held responsible for errors or
consequences arising from the use of information contained in these “Just Accepted” manuscripts.
is published by the American Chemical Society. 1155 Sixteenth Street N.W.,
Washington, DC 20036
Published by American Chemical Society. Copyright © American Chemical Society.
However, no copyright claim is made to original U.S. Government works, or works
produced by employees of any Commonwealth realm Crown government in the course
of their duties.

Page 1 of 6
ACS Medicinal Chemistry Letters
1
2
3
4
5
6
7
8
9
3,5-Disubstituted-indole-7-carboxamides as IKK inhibitors:
Optimization of Oral Activity via the C3 Substituent
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
Jeffrey K. Kerns,*† Jakob Busch-Petersen,† Wei Fu,† Jeffrey C. Boehm,† Hong Nie,† Michael
Muratore,† Ann Bullion,† Guoliang Lin,† Huijie Li,† Roderick Davis,† Xichen Lin,† Ami S.
Lakdawala, Rick Cousins,‡ Rita Field,‡ Jeremy Payne,‡ David D. Miller,‡ Paul Bamborough,‡ John
A. Christopher,‡ Ian Baldwin,‡ Ruth R. Osborn,† John Yonchuk,† Edward Webb,† William L.
Rumsey†
†GlaxoSmithKline Inc., 709 Swedeland Road, King of Prussia PA 19406,
‡GlaxoSmithKline R&D, Medicines Research Centre, Gunnels Wood Road, Stevenage, Hertfordshire, SG1 2NY, UK
O
O
O
O
S
O
O
S
S
N
F
N
N
N
H
H
H
H2N
O
H2N
H2N
O
O
2
24
(R)-28
ABSTRACT: IB Kinase  (IKK or IKK2) is a key regulator of nuclear factor kappa B (NF-B) and has received attention as
a therapeutic target. Herein we report on the optimization of a series of 3,5-disubstituted-indole-7-carboxamides for oral
activity. In doing so we focused attention on potency, ligand efficiency (LE), and physicochemical properties and have
identified compounds 24 and (R)-28 as having robust in-vivo activity.
KEYWORDS: IB Kinase  IKK IKK2, NF-B, Indole carboxamide, Cyclic sulfone, LPS neutrophilia, LPS-TNF alpha,
Dog segmental LPS challenge
In this case, we advanced a series of indolecarboxamides.
The optimization of this series is described herein.
IB Kinase  (IKK or IKK2) plays a central role in a
signaling cascade that ultimately leads to translocation of
nuclear factor kappa B (NF-B) to the nucleus of the cell
where it is involved in the up-regulation of pro-
inflammatory mediators, cytokines, and adhesion
proteins.1 Targeting NF-B remains a key strategy in the
O
O
S
N
development
of
non-steroidal
anti-inflammatory
5
5
therapeutics.2,3,4 In response to extracellular mediators like
tumor necrosis factor- (TNF) and lipopolysaccharide
(LPS), IKK phosphorylates Ser32 and Ser36 of the protein
inhibitory kappa B alpha (IB.5,6,7 As a result, IB is
ubiquitinated by an E3 ligase and subsequently degraded
by the 26S proteasome revealing the nuclear translocation
sequence on NF-B.1 To date, no IKK inhibitors have
been approved for clinical use. This may be due to
increased secretion of the pro-inflammatory cytokine IL1
resulting from chronic IKK inhibition.8,9 During our work
it became clear that inhibiting IKK may be problematic,
however, the potential benefits warranted optimization of
a chemical series to achieve in-vivo efficacy to allow
exploration of its potential beneficial and adverse effects.
3
3
N
N
1
1
H
7
H
7
H2N
O
H2N
O
Compound
IKK pIC50
LE
1
2
5.8
7.6
0.44
37
0.36
22
Solubility (M)
PAMPA (nm/s)
370
250
Figure 1. Comparison of potency, ligand efficiency (LE),
solubility, and Parallel Artificial Membrane
Permeability (PAMPA) of early lead compounds10
ACS Paragon Plus Environment

ACS Medicinal Chemistry Letters
Table 1. Structure Activity Relationships for
Page 2 of 6
In a previous report, a novel series of potent, selective,
and ATP competitive inhibitors of IKK, namely the 3,5-
disubstituted indole-7-carboxamides, was described.10 In
this, selectivity was assessed against more than 45 kinases
and pIC50 values were <5.5 against the entire panel. Figure
1 shows two compounds described in the earlier work. Key
elements of the series important for high binding affinity
include a C3 sulfonamide, a C5 aromatic, and C7 primary
carboxamide. The binding hypothesis includes a tridentate
interaction between Y98 (NH) and C99 (CO, NH) and the
indole NH and primary carboxamide as well as a hydrogen
bond between K106 (NH3+) and/or D103 (NH) and the
sulfonamide oxygens. The C5 aromatic occupies a
hydrophobic region of the ATP site. We noted that while
2 achieved good binding potency, the ligand efficiency
(LE)11,12 had decreased relative to the less potent compound
1 lacking the C3 sulfonamide (Figure 1). Examining the
binding of compound 2 (Figure 2), the C3 substituent
projects into the solvent front and thus appeared suitable
for modulating physicochemical properties. We optimized
the C3 substituent to increase ligand efficiency and to
balance physicochemical properties to develop a therapy
for chronic obstructive pulmonary disease (COPD).
1
2
3
4
5
6
7
8
Substituted Piperidine Sulfonamides
R1
N
N
H
9
H2N
O
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
Entry
R1
LE
Aqueous
Solubility
(M)b
PAMPA
IKK
pIC50
(nm/s)c
a
3
7.8
0.31
0.31
173
200
O
O
O
S
N
O
4
8.0
185
160
S
N
5
6
7
8
8.1
(n=1)
0.31
0.29
0.30
0.29
162
36
93
85
240
318
O
O
O
O
S
N
O
7.5
8.2
7.7
O
S
N
290
140
O
S
N
O
O
S
H
N
O
S
O
O
9
8.1
0.37
0.34
33
8
3
NH2
O
10
8.0
270
S
N
O
S
O
11
8.1
0.32
41
310
N
O
aIKK pIC50 values are the mean of n >2 determinations unless
noted. Kinetic aqueous solubility was measured via HPLC
with UV detection. PAMPA values are n=1 determinations.
Figure 2. Model of 2 with human IKK based on the
X-ray structure of human IKK13,14
b
The cell activity was determined by treating monocytes
with lipopolysachharide (LPS) and measuring the
inhibition of tumor necrosis factor alpha (TNF a
product of NF-B transcription. Compound 4, was the
most potent in cells. These leads possessed low clearance
and low to moderate volumes of distribution in rat. The
differences in bioavailability, however, were striking. We
presumed the limiting factor was absorption given the low
clearance and noted that compounds with <30% oral
bioavailability and low oral AUC had low or moderate
PAMPA values while those with bioavailability >30% had
high (>200) PAMPA values. This observation allowed us
to use the PAMPA to prioritize compounds for PK
evaluation. The permeability was not important for high
cell potency (9 vs 2, 4, 6, 10). While there were clear
differences in solubility, this property did not appear to be
important for obtaining good oral exposure a likely
consequence of dosing the compounds as solutions.
To improve the solubility, we designed analogues with
amine substituents at the solvent front. As seen in Table 1,
amines were introduced to either a 2 or 3 carbon alkyl
sulfonamide. These gave similar potency to 2 but with no
improvement in ligand efficiency. The basicity of the
amine (see Supporting Information) did not appear to be
important for potency (5 vs. 6 and 10) supporting the idea
that the C3 vector accesses the solvent front. Importantly,
solubility was improved in the 3-carbon linked amines (3-
8). In addition, we could modulate permeability as
measured in our artificial membrane permeability assay
(PAMPA).15,16 In this regard, less basic tertiary amines (6,
10, 11) gave higher permeability than either more basic (3,
4), primary (9), or secondary amines (8). This permeability
SAR was important for optimization of the series.
Next, we examined the cellular potency and
pharmacokinetics (PK) of leading compounds (Table 2).
ACS Paragon Plus Environment

Page 3 of 6
ACS Medicinal Chemistry Letters
Table 2. Pharmacokinetic profile of lead compoundsa
1
2
3
4
Entry
Monocyte IC50
(M)b
Oral AUC
(ng/mL*hr)
1222
Clp
(mL/min/kg)
16
Vdss
(L/kg)
1
T1/2
(min)
69
%F
PAMPA
(nm/s)
250
2
0.19
58
(47, 69)
12
5
6
7
8
(1176, 1268)
998
(13, 18)
4
(1, 1)
1
(70, 68)
276
4
6
0.05
0.20
0.14
0.50
160
318
<3
(436, 1560)
2034
(4, 4)
8.9
(1, 1)
(279, 272)
71
(6, 18)
53
0.43
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
(2544, 1524)
48 + 42
(7.8, 9.9)
14
(0.37, 0.49)
3 + 1
(71, 71)
266 + 43
(60, 46)
3 + 1
9
(15, 14)
7.43
10
2083
0.84
105
46
270
(2012, 2153)
(8.42, 6.44)
(1.06, 0.61)
(122, 88)
(51, 40)
a Pharmacokinetic profiling was done in male Sprague Dawley rats (n=2, with the exception of compound 9 where n=3) using 5%
DMSO and 20% Cavitron for the i.v. leg and 5% DMSO and 6% Cavitron for the oral leg. All compounds were dosed at 2 mg/kg
for the oral leg with the exception of 10 which was dosed at 2.1 mg/kg. Values are the mean of at least two determinations.
b
Compound 10 had the greatest variability with IC50’s of 0.88 and 0.12M. See Supporting Information for assay details.
To assess in-vivo activity we compared compound 6 to
the previously reported 210 in an LPS induced neutrophilia
model in rat. Both compounds were given orally.
Compound 6 was administered at 50 umol/kg while
compound 2 was dosed at 100 mol/kg. While these
compounds exhibited good in-vitro potency and oral
exposure, both were weakly active in-vivo giving
approximately 30% inhibition of neutrophilia.
good potency and ligand efficiency. The sulfone is more
likely to be metabolically stable than the ketone.
Expanding the cyclic sulfone to the [3.2.1] bicyclosulfone
gave moderate potency with no gain in ligand efficiency
with both the endo (22) and exo (23) isomers. With the
simplified 6-membered ring with the sulfone in the 4-
position (24), however, we achieved high in-vitro potency.
Importantly, 24 showed good ligand efficiency, cellular
potency, lipophilicity (clogP=1.6), and artificial membrane
permeability (Table 4). The sulfone in the 3- position (25)
gave similar potency compared to the 5-membered system
but with lower ligand efficiency.
While these early data were disappointing, we sought to
improve the in-vivo activity by increasing the ligand
efficiency as smaller molecular weight with equivalent
potency might lead to better target exposure. As such, we
sought to increase the ligand efficiency by reducing
molecular weight while retaining good potency,
physicochemical properties, and pharmacokinetics. We
explored several variations at C3 of the indole-7-
carboxamide template. These are shown in Table 3.
Initially we incorporated a 2C linker to both a ketone (12)
and methyl sulfone (13) resulting in moderate potency but
improved ligand efficiency. Cyclization of the ketone to
both the cyclopentanone (14) and -lactam (15) produced
little potency improvement and while the ligand efficiency
for both these analogues was acceptable, the presumed
poor metabolic stability of the ketone and low
permeability of the lactam (PAMPA=86 nm/s) precluded
pharmacokinetic profiling. Methylation of the lactam (16)
resulted in decreased potency. Interestingly, potency
differentiation was obtained by incorporating a gem-
dimethyl into the lactam system with the 3,3-gem-
dimethyl lactam (18) being 10-fold more potent than the
100
24, ED50 = 7.6 mol/kg
(R)-28, ED50 = 21.7 mol/kg
90
80
70
60
50
40
30
20
10
0
3
30
Compound Dose
(mol/kg)
Figure 3. Comparison of inhibition of TNF alpha in
rats of compounds 24 and (R)-28.17
corresponding
4,4-gem-dimethyl
(17)
system.
Since 24 possessed favorable potency, ligand efficiency,
lipophilicity, and permeability, we determined its
pharmacokinetic profile in the rat. As seen in table 5, 24
has moderate in-vivo clearance with high oral
bioavailability. Indeed, the clearance of 24 was higher than
any of the previously discussed analogues. To address the
moderate clearance (35 ng/mL*hr), we planned several
modifications including: introducing a fluorine to the para
Conformational search and docking reveals that the gem-
dimethyl in 17 produces a very small perturbation to Arg20
and the loss of potency is driven by a polarity mismatch
between the lipophilic gem-dimethyl and the polar Arg20
(see Supporting Information). The 4-cyclohexanone (19)
showed moderate potency while the 3-cyclohexanone (20)
was similar in potency to the cyclopentanone (14) system.
Like the cyclopentanone the cyclic sulfone (21) also gave
ACS Paragon Plus Environment

ACS Medicinal Chemistry Letters
position of the distal biaryl, substituting alpha to the
Page 4 of 6
decreased (Table 4). Compound (R)-28 was obtained via
resolution of the racemate and was ~100x more potent than
the distomer (S)-28. Modeling (see Supporting
Information) of (R)-28 and (S)-28 reveals the loss in
potency arises from a steric clash between the gem-
dimethyl in (S)-28 and the Lys106 side-chain. This drives a
rotation of the ring with subsequent loss of the H-bond to
Lys106 . The pharmacokinetic profile of these compounds
(24, 26, 27, (R)-28) in rat is shown in Table 5. The para-F
analog 26 was favorable in terms of reducing the plasma
clearance while the dimethyl analog 27 showed increased
1
2
3
4
5
6
7
8
sulfone, and the combination of both modifications.
Table 3. Potency and LE for C3 Substituent Analogs
R1
N
H
9
H2N
O
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
a
Entry
R1
LE
IKK pIC50
6.9 (n=1)
7.2
plasma clearance on average.
Compound (R)-28,
O
possessing both the para-F and alpha-substituent,
however, reduced the clearance by twofold while
maintaining high oral bioavailability (94%).
Given these data, compounds 24 and (R)-28 were
profiled in a rat LPS-TNF alpha model of inflammation (see
Supporting Information). This offered greater throughput
12
13
0.41
0.42
O O
S
O
14
15
7.1
0.41
than the LPS-neutrophilia model.
In this model,
compound 24 had an ED50 of 7.6 mol/kg p.o. (2.8 mg/kg)
whereas compound (R)-28 demonstrated and ED50 of 21.7
mol/kg p.o. (9 mg/kg) (Figure 3).
Encouraged by these results, compounds 24 and (R)-28
were advanced to a dog pharmacokinetic experiment.
These results are shown in Table 5. Of the two, compound
(R)-28 demonstrated superior pharmacokinetics with low
clearance (1.86 ml/min/kg) and high oral bioavailability
(65%).
O
O
7.4
0.42
N
H
16
17
6.3
6.7
0.35
0.35
N
CH3
CH3
H3C
O
N
H
H3C
To demonstrate in-vivo efficacy in a second species, we
used a dog segmental LPS challenge model. In this model,
one lobe received localized delivery of saline as control
while the contralateral lobe received localized delivery of
LPS solution (see Supporting Information). These data are
shown in Figure 4. In this model, compound 24 had an
ED50 of 2.9 mol/kg p.o. (1.1 mg/kg) whereas compound
(R)-28 demonstrated an ED50 of 1.8 mol/kg p.o. (0.74
mg/kg).
CH3
O
18
7.7
0.41
N
H
O
19
6.3 (n=1)
7.1
0.35
0.39
20
O
O
O
O
S
100
21
22
23
7.0
7.4
7.1
0.34
0.36
0.35
O
75
S
50
O
O
S
24, ED50 = 2.9 mol/kg
25
(R)-28, ED50 = 1.8 mol/kg
O
0
S O
1
3
10
30
24
25
8
0.42
0.37
Compound Dose
(mol/kg)
O
O
S
Figure 4. Comparison of compounds 24 and (R)-28 in
6.8
inhibition of neutrophilia in male beagle dogs.17
aIKK pIC50 values are the mean of n >2 determinations unless
noted. Compounds were tested as racemic mixtures.
Preparation of the sulfones 24 and 26 was completed in
five steps as shown in Scheme 1. Condensation of ester 29
with ketone 30 using TMSOTf and Et3SiH produced the
intermediate cyclic sulfides. Oxidation to the sulfone was
accomplished using either oxone or trifluoroacetic
These substitutions were well tolerated as the
compounds maintained potency, ligand efficiency, cell
potency, and permeability though the solubility had
ACS Paragon Plus Environment

Page 5 of 6
ACS Medicinal Chemistry Letters
anhydride / urea•hydrogen peroxide. Completion of the
via condensation, oxidation of the sulfide to the sulfone
followed by conversion of the ester to the amide and finally
Suzuki-Miyaura coupling.
1
2
3
4
5
6
7
8
target compounds was achieved via ester hydrolysis and
amide formation followed by Suzuki-Miyaura cross-
coupling. The preparation of dimethyl analogs 27 and 28 is
shown in Scheme 2 and began with condensation of indole
32 with ketone 34 (see Supporting Information for
synthetic details to ketone 34). The synthesis was
completed in a manner analogous to compounds 24 and 26
Inhibition of IKK has attracted attention given its role
in activation of NF-B. To date several optimization
campaigns have been described across a diverse range of
chemical series. One key challenge in this area of drug
discovery has been the identification of potent inhibitors.
9
Scheme 1. Synthesis of 24 and 26
Scheme 2. Synthesis of 27 and 28
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
O
S
O
S
O
S
O
O
O
O
O
S
S
S
O
34
c) NaOH (88%)
d) EDC, HOBT,
NH3 (91%)
30
Br
O
c) LiOH (94%)
d) TBTU, NH3
(64%)
e) PdCl2(dppf)
PhB(OH)2
(or)
R
Br
Br
R
a) TMSOTf, Et3SiH
(40-80%)
Br
a) TMSOTf,
Et3SiH, (52%)
N
N
H
N
N
N
H
b) Oxone (71%)
(or)
TFAA, urea-H2O2
(80-99%)
N
e) PdCl2(dppf)
PhB(OH)2
(or)
H
H
H
b) mCPBA, (89%)
H
EtO
O
H2N
O
EtO
O
O
O
H2N
O
O
O
29
p-F-PhB(OH)2
24
26
- R=Ph, 30-60%
- R=p-F-Ph, 33%
35
31
32
p-F-PhB(OH)2
27
28
R=Ph, 29%
R=p-F-Ph, 96%
Table 4. In-vitro and Physicochemical Property Profile of Leads
a
Entry
R1, R2, R3
H, H, H
LE
Cell IC50
(M)a
Aqueous
Solubility(M)c
PAMPA
(nm/s)d
IKK pIC50
O
O
24
8.0
0.42
0.4
0.08
130
277
280
330
S
R2
R3
R1
26
F, H, H
7.9
8.1
0.05, 0.81
0.11 (n=1)
--
N
H
27 (rac)
H, Me, Me
0.4
39
H2N
O
(R)-28
F, Me, Me
8.1 (R)
0.38
0.13
32
283
Values are the mean of n >2 determinations unless noted otherwise. cKinetic solubility was measured via HPLC using UV
a
detection. For 27 and (R)-28 chemiluminescent nitrogen detection (CLND) was used.18 dPAMPA values are n=1 determinations
except for 24 and (R)-28 (n=3).
Table 5. Pharmacokinetic profile of lead compoundsa
Entry
Species
Rat
Oral AUC
(ng/mL*hr)
904
Clp
(mL/min/kg)
35
Vdss
(L/kg)
2.8
T1/2
(min)
94.8
%F
PAMPA
(nm/s)
24
97
277
(866, 942)
753 + 219
(31, 39)
(2.6, 3)
(94.8, 94.2)
0.949 + 0.117
(104, 89)
52.6 + 11.8
Dogb
Rat
23.6 + 2.69
1.54 + 0.22
26
27
1270
(1258, 1282)
1434
23.5
(25.4, 21.6)
51.1
3.7
(3.2, 4.1)
7.2
132
47.4
(51.2, 43.7)
115
280
330
283
(114, 150)
140.4
Rat
Rat
(1600, 1266)
1961
(40.9, 61.3)
13.2
(7.4, 7)
4.7
(121.8, 159)
270
(104, 126)
94.1
(R)-28
(1543, 2379)
(14.9, 11.4)
(5.4, 4.0)
(282, 264)
(89.8, 99.7)
Dogb
8203 + 153
1.86 + 0.89
2.87 + 0.06
20.9 + 7.24
65.3 + 15.0
a Pharmacokinetic profiling was done in male Sprague Dawley rats (n=2) or male Beagle dogs (n=3) using 5% DMSO and 20%
Cavitron for the i.v. leg and 5% DMSO and 6% Cavitron for the oral leg. All compounds were dosed at 1 mg/kg and 2 mg/kg for
the i.v. and oral legs respectively. b The dose for compound 24 was 1.11 mg/kg and 2.03 mg/kg for the i.v. and oral legs respectively.
b The average dose for compound (R)-28 was 0.77 mg/kg and 2.40 mg/kg for the i.v. and oral legs respectively.
ACS Paragon Plus Environment

ACS Medicinal Chemistry Letters
Page 6 of 6
response domain in I kappa B alpha to multiple pathways for
NF-kappa B activation. Molecular and Cellular Biology 1995, 15
(5), 2809-18.
Herein, we describe some of the details of the optimization
of the C3 position of a series of indole-7-carboxamides. We
found that while the piperidine sulfonamide could be used
to modulate the solubility, in-vivo exposure correlated
with PAMPA permeability. In addition, we have been able
to improve the ligand efficiency of the series through
modulation of the C3 substituent. This has given rise to
compounds 24 and (R)-28 both of which demonstrate
good pharmacokinetics and in-vivo activity.
1
2
3
4
5
6
7
8
7.
Brown, K.; Gerstberger, S.; Carlson, L.; Franzoso, G.;
Siebenlist, U., Control of I kappa B-alpha proteolysis by site-
specific, signal-induced phosphorylation. Science 1995, 267
(5203), 1485-1488.
8.
Greten, F. R.; Arkan, M. C.; Bollrath, J.; Hsu, L.-C.;
Goode, J.; Miething, C.; Göktuna, S. I.; Neuenhahn, M.; Fierer,
J.; Paxian, S.; Van Rooijen, N.; Xu, Y.; O'Cain, T.; Jaffee, B. B.;
Busch, D. H.; Duyster, J.; Schmid, R. M.; Eckmann, L.; Karin,
M., NF-κB Is a Negative Regulator of IL-1β Secretion as
Revealed by Genetic and Pharmacological Inhibition of IKKβ.
Cell 2007, 130 (5), 918-931.
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
Supporting Information:
Data tables, figures, experimental procedures and
characterization data.
9.
Zhong, Z.; Umemura, A.; Sanchez-Lopez, E.; Liang,
S.; Shalapour, S.; Wong, J.; He, F.; Boassa, D.; Perkins, G.; Ali,
Syed R.; McGeough, Matthew D.; Ellisman, Mark H.; Seki, E.;
Gustafsson, Asa B.; Hoffman, Hal M.; Diaz-Meco, Maria T.;
Moscat, J.; Karin, M., NF-κB Restricts Inflammasome
Activation via Elimination of Damaged Mitochondria. Cell
2016, 164 (5), 896-910.
Author Addresses: Current work address for JKK,
GlaxoSmithKline 1250 South Collegeville Road,
Collegeville, PA 19426.
Acknowledgments: The authors would like to thank
Catherine Booth-Genthe, Sandra Umbrecht, Casey Kmett,
Brian Peck, and Phil Landis for their contributions to the
pharmacokinetic profiling of the lead compounds.
10.
Miller, D. D.; Bamborough, P.; Christopher, J. A.;
Baldwin, I. R.; Champigny, A. C.; Cutler, G. J.; Kerns, J. K.;
Longstaff, T.; Mellor, G. W.; Morey, J. V.; Morse, M. A.; Nie,
H.; Rumsey, W. L.; Taggart, J. J., 3,5-Disubstituted-indole-7-
carboxamides: The discovery of a novel series of potent,
Abbreviations:
selective inhibitors of IKK-β. Bioorganic
Chemistry Letters 2011, 21 (8), 2255-2258.
& Medicinal
IKK Inhibitor of IB Kinase  NF-B, nuclear factor
kappa B; IB inhibitory kappa B alpha LE, ligand
efficiency; COPD, chronic obstructive pulmonary disease;
11.
Kuntz, I. D.; Chen, K.; Sharp, K. A.; Kollman, P. A.,
The maximal affinity of ligands. Proceedings of the National
Academy of Sciences 1999, 96 (18), 9997-10002.
EDC,
1-Ethyl-3-(3-dimethylaminopropyl)carbodiimide;
12.
Hopkins, A. L.; Groom, C. R.; Alex, A., Ligand
PAMPA, parallel artificial membrane permeability assay;
TNF tumor necrosis factor-; LPS, lipopolysaccharide;
efficiency: a useful metric for lead selection. Drug Discovery
Today 2004, 9 (10), 430-431.
ATP,
adenosine
triphosphate;
mCPBA,
meta-
13.
Liu, S.; Misquitta, Y. R.; Olland, A.; Johnson, M. A.;
chloroperoxybenzoic acid; DPPF, 1,1′-Ferrocenediyl-
bis(diphenylphosphine); TBTU, 2-(1H-Benzotriazole-1-yl)-
Kelleher, K. S.; Kriz, R.; Lin, L. L.; Stahl, M.; Mosyak, L., Crystal
Structure of a Human IκB Kinase β Asymmetric Dimer.
Journal of Biological Chemistry 2013, 288 (31), 22758-22767.
1,1,3,3-tetramethylaminium
tetrafluoroborate;
TFAA,
trifluoroacetic anhydride; TMSOTf, trimethylsilyl triflate;
DMSO, dimethylsulfoxide; PK, pharmacokinetic; AUC,
area under curve; Clp, clearance plasma; Vdss, volume of
distribution steady state; T1/2, half-life; %F, oral
bioavailability
14.
During this work, the x-ray crystal structure of IKK
beta was not available and all optimization was done using a
homology model.
15.
Kansy,
M.;
Senner,
F.;
Gubernator,
K.,
Physicochemical High Throughput Screening:ꢀ Parallel
Artificial Membrane Permeation Assay in the Description of
Passive Absorption Processes. Journal of Medicinal Chemistry
1998, 41 (7), 1007-1010.
1.
Karin, M.; Yamamoto, Y.; Wang, Q. M., The IKK NF-
[kappa]B system: a treasure trove for drug development. Nat
Rev Drug Discov 2004, 3 (1), 17-26.
16.
Prediction of human intestinal permeability using artificial
membrane permeability. International Journal of
Pharmaceutics 2003, 257 (1), 245-251.
17. All animal studies were conducted in accordance
Sugano, K.; Nabuchi, Y.; Machida, M.; Aso, Y.,
2.
transcription factors. Oncogene 1999, 18 (49), 6853-6866.
3. Taniguchi, K.; Karin, M., NF-κB, inflammation,
Pahl, H. L., Activators and target genes of Rel/NF-kB
immunity and cancer: coming of age. Nature Reviews
Immunology 2018, 18, 309.
with the GSK Policy on the Care, Welfare and Treatment of
Laboratory Animals and were reviewed the Institutional
Animal Care and Use Committee either at GSK or by the
ethical review process at the institution where the work was
performed.
4.
Rothschild, D. E.; McDaniel, D. K.; Ringel-Scaia, V.
M.; Allen, I. C., Modulating inflammation through the
negative regulation of NF-κB signaling. Journal of Leukocyte
Biology 2018, 103 (6), 1131-1150.
18.
Kestranek, A.; Chervenak, A.; Longenberger, J.;
5.
Whiteside, S. T.; Ernst, M. K.; LeBail, O.; Laurent-
Placko, S., Chemiluminescent Nitrogen Detection (CLND) to
Measure Kinetic Aqueous Solubility. In Current Protocols in
Chemical Biology, John Wiley & Sons, Inc.: 2009.
Winter, C.; Rice, N.; Israël, A., N- and C-terminal sequences
control degradation of MAD3/I kappa B alpha in response to
inducers of NF-kappa B activity. Molecular and Cellular
Biology 1995, 15 (10), 5339-45.
6.
Brockman, J. A.; Scherer, D. C.; McKinsey, T. A.; Hall,
S. M.; Qi, X.; Lee, W. Y.; Ballard, D. W., Coupling of a signal
ACS Paragon Plus Environment