Anilino-monoindolylmaleimides as potent and selective JAK3 inhibitors

Article abstract of DOI:10.1016/j.bmcl.2014.01.001

We designed a series of anilino-indoylmaleimides based on structural elements from literature JAK3 inhibitors 3 and 4, and our lead 5. These new compounds were tested as inhibitors of JAKs 1, 2 and 3 and TYK2 for therapeutic intervention in rheumatoid art

Full text of DOI:10.1016/j.bmcl.2014.01.001

Bioorganic & Medicinal Chemistry Letters 24 (2014) 1116–1121
Contents lists available at ScienceDirect
Bioorganic & Medicinal Chemistry Letters
journal homepage: www.elsevier.com/locate/bmcl
Anilino-monoindolylmaleimides as potent and selective JAK3
inhibitors
a
b
b
Mark E. McDonnell a, Haiyan Bian a, Jay Wrobel a, , Garry R. Smith , Shuguang Liang , Haiching Ma ,
⇑
Allen B. Reitz a
a Fox Chase Chemical Diversity Center, Inc., 3805 Old Easton Road, Doylestown, PA 18902, United States
b Reaction Biology, Corp., One Great Valley Parkway, Suite 2, Malvern, PA 19355, United States
a r t i c l e i n f o
a b s t r a c t
Article history:
We designed a series of anilino-indoylmaleimides based on structural elements from literature JAK3
inhibitors 3 and 4, and our lead 5. These new compounds were tested as inhibitors of JAKs 1, 2 and 3
and TYK2 for therapeutic intervention in rheumatoid arthritis (RA). Our requirements, based on current
scientific rationale for optimum efficacy against RA with reduced side effects, was for potent, mixed JAK1
and 3 inhibition, and selectivity over JAK2. Our efforts yielded a potent JAK3 inhibitor 11d and its eutom-
er 11e. These compounds were highly selective for inhibition of JAK3 over JAK2 and TYK. The compounds
displayed only modest JAK1 inhibition.
Received 9 September 2013
Revised 30 December 2013
Accepted 2 January 2014
Available online 9 January 2014
Keywords:
JAK3 inhibitor
Anilino-monoindolylmaleimide
Rheumatoid arthritis
JAK2 selective inhibitor
JAK1 inhibitor
Ó 2014 Elsevier Ltd. All rights reserved.
The four cytoplasmic tyrosine kinases in the family named
Janus Kinases (JAK1, JAK2, JAK3 and TYK2) play critical roles in
the cytokine receptor binding-triggered signal transduction
through Signal Transducers and Activators of Transcription
(STATs). Several small molecule JAK inhibitors have now shown
success in clinical trials and two have been approved by the FDA
for therapeutic use. Tofacitinib 11–4 a potent pan-JAK inhibitor
was approved for rheumatoid arthritis (RA) in 2012. Its side effect
profile is consistent with its mode of action: upper respiratory
infections attributable to its JAK1 inhibitory activity, anemia and
neutropenia linked to its JAK2 inhibitory activity and elevated
LDL levels possibly caused by its effects on both JAK1 and 2.3,5
Ruxolitinib 2 is a JAK1,2 inhibitor that was approved in 2011 for
myelofibrosis and is currently being evaluated in the clinic for
RA.5 Other JAK inhibitors are also being investigated in humans
for RA including those that are reported to be selective for JAK1
(GLPG0634), JAK2 (CEP33779) and JAK3 (VX-509).3,5 Interestingly
these latter three, despite different JAK selectivity preferences,
have demonstrated efficacy in RA in Phase II studies.5
CN
N
N
N
O
N
N
CN
O
N
N
O
1
2
N
H
N
H
N
H
N
CF3
2
N
N
N
O
R =
3
N
O
3
R
H
OH
4
H
N
H
O
O
N
O
O
5
X
N
H
4
N
H
We thought we could derive the maximum benefit for a safe
and effective RA therapeutic agent through the development of a
potent JAK1 and JAK3 mixed inhibitor with selectivity over JAK2
based on the following considerations. JAK2 inhibition would not
be desirable due to its potential to induce anemia as seen in the
non-selective agents above. JAK3 inhibition is
(CH2)n
Het
N
N
N
N
NH
H
N
N
5
6 (Het = e.g
,
)
N
⇑
Corresponding author.
E-mail address: jwrobel@fc-cdci.com (J. Wrobel).
0960-894X/$ - see front matter Ó 2014 Elsevier Ltd. All rights reserved.
http://dx.doi.org/10.1016/j.bmcl.2014.01.001

M. E. McDonnell et al. / Bioorg. Med. Chem. Lett. 24 (2014) 1116–1121
1117
preferable since it is found predominantly in hematopoietic cells
while JAK1 and 2, and TYK2 are ubiquitously expressed.6 Although
some investigators have argued that JAK3 selectivity may be suffi-
cient for treatment of RA via stimulation through IL-2 pathway,7
examine the nature and length of the appending group [X and
(CH2)n] and explore different heterocyclic moieties in an effort to
maintain or increase JAK3 inhibitor potency, selectivity over JAK2
and increase potency for JAK1. In fact small molecule modeling re-
vealed that low energy conformations of compounds designed
from framework 6, such as 7a, (Fig. 2) could be superimposed with
the X-ray conformation of 413 with good overlap of their respective
side chains, and this provided impetus for our foray into the syn-
thesis of these analogs.
The synthesis of compounds related to 6 is shown in Schemes
1–3. The 4-anilino-maleimides 7, 8, 9, 10a and 11 were prepared
via reaction of 3-hydroxymaleimide 13 with the anilines (14)
heated in acetic acid according to established methods (Scheme 1).22
The starting 4-hydroxy maleimides 13 were commercially available
(Ar = 3-indolyl) or prepared from the corresponding 3-substituted
acetamide 12 (Ar = phenyl, 1-methyl-3-indolyl) using literature
procedures.22 4-Bromo-maleimide 15 was commercially available
and used to prepare 10b.
The starting anilines 14 were prepared by procedures shown in
Schemes 2 and 3. Starting nitro-bromides 16 were commercially
available. The reaction of amines such as 18, 19, 21 and 22 with
2,4-difluoropyridine is known to add to the pyridine 4-position
to ultimately provide, in our case, the 4-amino-2-fluoro-pyridine
regiochemistry for 14f–k, o–w.23,24 The starting nitro-amines 21
that afforded anilines 14o–u and final compounds 11a–c, g–i were
commercially available. To produce enantiomerically pure anilines
14v and w for the production of target compounds 11e and f, we
used commercially available S or R-pyrrolidin-3-ol (22 for the S iso-
mer). The key step in the synthesis of 14v and w was reaction of
the hydroxyl containing compound 23 (or its enantiomer) with
1-iodo-3-nitrobenene using copper catalyzed conditions described
by Buchwald25 to form the corresponding 3-nitrophenoxy conge-
ner. The nitro group of this compound was then reduced to the ani-
line 14v. The method of preparation of 11e is given in the reference
section.26 The (R)-enantiomer (14w, for 11f) was synthesized in
analogous fashion from (R)-pyrrolidinol.
The imidazole containing analogs 7a–e are shown in Table 2.
Our small molecule modeling suggested that meta and para side
chains on the aniline should be able to access conformations that
have substantial overlap with the side chains of 3 and 4 when
the molecules are superimposed. However side chains from the
ortho position should have a steric clash with the 4-maleimide in-
dole moiety thus preventing a conformation similar to the bioac-
tive ones of 3 and 4, or clash with JAK3 residues within the
binding site. Indeed the ortho analog 7e had substantially poorer
activity against all the JAK isoforms than did the meta and para
analogs 7a–d. With respect to the meta versus para positions, the
longer side chain (n = 3) of the meta isomer (7a) was superior in
potency for JAK3 inhibition to the shorter isomer 7b (n = 2). The
opposite was true for the para isomers in that the shorter chain
7c, n = 2) was superior in potency to the longer side chain (7d,
JAK1 and JAK3 both cooperate in signaling through the cc-contain-
ing cytokine receptors, but JAK1 is thought to play a dominant role.8
Therefore inhibition of both JAK1 and 3 may be required for opti-
mum efficacy.
Agents with the mixed JAK profile we desired have not yet been
described. Several different investigators reported compounds
with varying selectivity for JAK3.7,9–12 Compound 3 was reported
by Novartis researchers13 to have particularly high selectivity for
JAK3 over JAK1, JAK2, and TYK2. The authors provided an X-ray
co-crystal structure of a related analog (4) to explain this high
selectivity. Other researchers described JAK1 inhibitors that were
selective against JAK2 but JAK3 activity was not reported.14–17 Re-
cently, a series of diamino-triazole derivatives were shown to have
selectivity for TYK2 and JAK1 over JAK2 and 3.18 In the last several
years JAK2 selective inhibitors have also been disclosed.19,20 To
date, no analogs with potent JAK1 and 3 inhibitory activities that
were selective over JAK2 have been reported.
We recently profiled a number of known kinase inhibitors in
our Kinase HotspotSM assay.21 One compound in particular, PKCb
inhibitor JP539654 (5),22 showed strong inhibition of JAK3, modest
inhibition of JAK1, and excellent selectivity over JAK2 and TYK2
(Table 1). The potent PKCb inhibitor activity of this compound
was confirmed in our assay (data not shown). The profile of this
compound was similar to compound 3 in that JAK1 inhibition
activity, although considerably weaker than JAK3 inhibition activ-
ity, was superior to the inhibition activity of JAK2. According to the
X-ray model, the JAK3 selectivity of 3 and 413 is due to an H-bond
between the maleimide 2-carbonyl oxygen atom of 4 and D967 of
JAK3. A similar H-bond cannot occur between 4 and JAKS 1, 2 or
TYK2. This is because these isozymes have a glycine adjacent to
this aspartate while JAK3 has an alanine (A966) at this position.
The A966 induces a conformation of the adjacent D967 to form a
H-bond, via a bridged water molecule, to the maleimide carbonyl
oxygen atom of 4.
We reasoned that the JAK3 selectivity of 5 might be due to a
bioactive conformation where the distal 5-maleimide carbonyl
oxygen atom H-bonds (via a bridged water molecule) to D967 thus
orienting the maleimide 4-substituent of 5 (i.e. the indole contain-
ing the propyl-imidizole unit) into to the region of JAK3 occupied
by the 3-phenyl piperidinone substituent of 4. To support this
hypothesis, we carried out a small molecule molecular modeling
study to show that a low energy conformation of 5 could be super-
imposed with the X-ray conformation of 4 (Fig. 1) and that their
respective side chains have substantial overlap.
We envisioned that we could produce novel JAK3 inhibitors by
removing the side chain of 5 and appending it to the 4-phenylami-
no ring as shown by 6. Within this proposed framework we could
Table 1
N
O
F
JAK inhibition of standards and lead analogsa
O
O
F
F
F
Compd
IC50 (nM)
JAK2/JAK3
F
N
JAK1
JAK2
JAK3
TYK2
N
1b
2
3.8
0.6
311
770
10.7
0.7
1.4
14.6
0.5
17
24
0.4
1691
2310
8
0
N
N
N
3
NAd
3850
>20,000
226
5c
N
a
N
Tested in triplicate, SEM generally 20%, on one occasion unless otherwise
noted.
N
b
Tested on >20 different occasions.
Tested on 2 different occasions.
NA = IC50 > 10,000 nM.
c
Figure 1. Superposition of 4 (yellow) and 5 (red) (two poses of approximately 90°
d
difference).

1118
M. E. McDonnell et al. / Bioorg. Med. Chem. Lett. 24 (2014) 1116–1121
NH2
NO2
F
NO2
F
O
N
a
b
O
for 7a-e
F
O
F
O (CH2)n
14a-e
O (CH2)n
O (CH2)n
Br
F
17
16
16
N
N
n = 1,2
N
N
NH2
NH2
N
d
c, b
N
N
N
for 8a-e, 10a,b
O
O (CH2)n
NH
O (CH2)n
NH2
H
N
O
14f-j
n = 1,2
18
O
O
O
N
H
O
N
N
F
N
N
H
NH2
NO2
N
7a
N
f
d, b
for 8f
16
O
O
Figure 2. Superposition of 4 (yellow) and 7a (red) (two poses of approximately 90°
difference).
N
NHCH3
14k
19
N
F
NH2
NH2
H
N
H
N
O
O
g
O
O
NH2
for 9a, b
14
18 (meta isomer)
R
Ar
R
a
O
HN
O
Ar
OH
Ar
b
N
HN
13
7, 8, 9, 10a, 11
Ar = 3-indolyl, 1-methyl-3-indolyl, phenyl
12
14l, m
A
A = CH, N
H
H
N
N
O
O
14
b
O
O
NH2
NO2
R
h
b
HN
for 9c,d
Br
16
15
10b
O
O
X
HN
HN
X
Scheme 1. Reagents and conditions: (a) Ar = phenyl: (CO2CH3)2, KOH/THF, 68%; (b)
HOAc, 100 °C, 50–95%.
14n
20
X
X = H or F
X
n = 3). The meta isomer 7a also showed the best potency of this set
with respect to JAK1 inhibition. Although none of the compounds
exhibited the potency we required, our crude model proved useful
and gave us confidence that we could improve potency, at lease
with respect to JAK3 inhibition, with additional analog synthesis.
We probed our model further using a side chain with a 2-fluoro-
4-aminopyridine terminal unit (Table 3). Once again the ortho iso-
mer (8c) showed poor activity. The para isomers (8a, b) were not
substantially better than the para isomer in the imidazole series
(7c, d, Table 2). However the meta isomer (8d) showed a four-fold
improvement in potency over its imidazole counterpart 7a (note
the chain length atom counts of 7a and 8d are the same, i.e. a four
atom spacer between the phenyl and heterocyclic rings). The JAK2
potency also increased although the compound was still over 70
fold selective for JAK3 over JAK2. N-methylation of the indole
nitrogen (8e) led to a less active analog. While the JAK3 potency
of the exocyclic amino pyridine methylated compound (8f) was
not significantly lower than that for 8d, the JAK2 selectivity and
the JAK1 potency decreased relative to 8d.
Scheme 2. Reagents and conditions: (a) imidazole, NaH, DMF, 70–80%; (b) H2, 10%
Pd/C, EtOH, 90–95%; (c) R = H: NaN3, DMF, 60 °C, 95–100%; (d) 2,4-difluoropyridine,
DIPEA, DMF, 120 °C microwave, 40–60%; (f) NH2CH3, DIPEA, THF, 50 °C, 95%; (g) 2-
fluoro-pyridine or 2-chloro-pyrazine, Cs2CO3, DMF, 120 °C microwave, 10–45%; (h)
aniline or 3-5 difluoro aniline, Cs2CO3, DMF, 120 °C microwave, 20–95%.
NH2
NO2
N
nN
m
F
a, b
nNH
m
X
X
14o-u
21
for 11a-d, g-i
X= O or bond
n, m = 1 or 2
HO
(S)
a
c, b
HO (S)
N
N
N
H
F
22
23
For 8d, the JAK1 activity was still not in the potency range we
desired and additional modifications were sought. In this regard
a set of analogs with different 6-membered ring heterocyclic and
substituted phenyl compounds were examined (9a–d, Table 4).
The 2-pyridyl compound 9a and 2,5-pyrazine analog 9b were con-
siderably less potent than 8b. Note that neither compound has
their terminal ring (pyridine for 9a or pyrazine for 9b) nitrogen
atom in the para position (to the exocyclic amine) as it is for 8d.
Compounds 9c and 9d that have phenyl or fluorophenyl rings de-
void of pyridine-like nitrogen atoms are also much less potent than
8d. Thus it appears that the presence and trajectory of the pyridine
O
R analog (14w) for 11f made in same
fashion from corresponding R-
pyrrolidinol
(S)
N
N
F
H2N
14v
for 11e
Scheme 3. Reagents and conditions: (a) 2,4-difluoropyridine, DIPEA, DMF, 60–
120 °C, 40–60%; (b) H2, 10% Pd/C, EtOH, 90–95%; (c) 1-iodo-3-nitrobenzene, CuI,
3,4,7,8-tetramethylphenanthroline (10%), Cs2CO3, THF, 100 °C, 26%.
nitrogen atom of 8b is very important for its potency as a JAK3
inhibitor.

M. E. McDonnell et al. / Bioorg. Med. Chem. Lett. 24 (2014) 1116–1121
1119
Table 2
Table 4
JAK inhibition of imidazole containing analogsa
JAK inhibition of 4-fluoro-pyridinyl amine replacement analogsa
H
O
N
H
N
O
O
O
NH
o
NH
H
N
N
O
Ar
N
N
H
m
N
(CH2)n
O
H
p
Compd
9a
9b
9c
9d
Cmpd
Position
n=
IC50 (nM)
JAK2/JAK3
N
F
JAK1
JAK2
JAK3
TYK2
N
N
7a
7b
7c
7d
7e
m
m
p
p
o
3
2
2
3
2
300
NAb
NA
8640
NA
NA
NA
NA
NA
NA
128
1790
278
1148
9367
NA
NA
7368
NA
NA
78
6
36
9
Ar
F
IC50 JAK3 (nM)
1499
408
1380
1387
1
a
Compounds tested in triplicate, SEM generally 20%.
a
Compounds tested in triplicate, SEM generally 20%.
NA = IC50 > 10,000 nM
b
We also examined replacing the 4-maleimide indole moiety
Table 5
with smaller groups and thus prepared phenyl and hydrogen
replacement compounds (10a and b, Table 5). These compounds
had greatly reduced activity when compared to 8d. Upon reflec-
tion, these results are not surprising when examining the X-ray
structure of JAK3 complexed with 4 [Ref. 13 and Protein Data Bank
(www.rcsb.org) file 3PJC]. In this structure the phenyl portion of
the indole moiety of 4 makes four hydrophobic contacts with
JAK3. These interactions would be lost or reduced when this indole
is substituted by a phenyl or smaller groups. In addition, the NH of
the indole of 4 (and presumably 8d) projects into bulk solvent pos-
sibly interacting with solvent water molecules and this interaction
unavailable for 10a and b.
We then examined constrained analogs of 8d (Table 6, 11a–f),
via transformation of the flexible ethyl amine side chain of 8d into
piperidine, pyrrolidine or azetidine ring systems, in order reduce
the number of unproductive conformations (from a JAK3 binding
point of view). In addition, a set of compounds was prepared
(11g–i) that further rigidified the analogs by also eliminating the
oxygen atom linker with a direct bond to the aniline ring. Except
for the azetidine analog 11i, which did show appreciable activity
for JAK3 inhibition, this latter set exhibited no JAK inhibition activ-
JAK inhibition of 4-indole replacement analogsa
H
O
N
O
NH
R
H
N
N
F
O
Compd
R
IC50 (nM)
JAK1
JAK2
JAK3
TYK2
10a
10b
Ph
H
2174
NAb
11,080
NA
576
NA
NA
NA
a
Compounds tested in triplicate, SEM generally 20%.
NA = IC50 > 10,000 nM.
b
comparison to JAK3 potency and was approximately 100 fold
selective for JAK3 over JAK2. The JAK1 potency had not improved
however. Since this compound was a racemic mixture, the enanti-
omers of 11d were prepared. The S-isomer 11e was significantly
more potent as a JAK 1/3 inhibitor than the R-enantiomer 11f.
Our simple overlay model was not able to predict this eutomer/dis-
tomer preference. Low energy conformations of either enantiomer
11e or f, when superpositioned with the JAK3 X-ray conformation
of 4, appeared to overlay equally well with 4 (data not shown).
ity at the highest doses tested (10 lM).
The piperidine set (11a, b) as well as the azetidine congener
11c, had activity that was 12–50 fold lower than lead 8d. However
the pyrrolidine analog 11d showed improved potency over 8d in
Table 3
JAK inhibition of 4-fluoro-pyridinyl amine analogsa
H
O
N
O
F
R'
NH
N
N
o
O
(CH2)n
N
R
m
p
Compnd
Position
n=
R
R0
IC50 (nM)
JAK2/JAK3
JAK1
JAK2
JAK3
TYK2
8a
8b
8c
8db
8e
8f
p
p
o
m
m
m
3
2
2
2
2
2
H
H
H
H
CH3
H
H
H
H
H
H
CH3
1060
2058
NAc
423
1784
NA
1270
9687
NA
2130
1637
490
135
201
NA
29
179
46
NA
9844
NA
NA
5104
995
9
48
—
73
9
11
a
b
c
Tested in triplicate, SEM generally 20%, on one occasion unless noted.
Tested on 5 occasions.
NA = IC50 > 10,000 nM.

1120
M. E. McDonnell et al. / Bioorg. Med. Chem. Lett. 24 (2014) 1116–1121
Table 6
JAK inhibition of constrained analogs of 8da
H
O
N
O
N
NH
n N
m
F
*
N
H
X
Compd
X
n=
m=
Absolute stereochem⁄
IC50 (nM)
JAK2/JAK3
JAK1
JAK2
JAK3
TYK2
11a
11b
11c
11db
11ec
11f
11g
11h
11i
O
O
O
O
O
O
Bond
Bond
Bond
2
1
1
1
1
1
1
2
1
2
3
1
2
2
2
2
2
1
NA
Racemic
NA
Racemic
S
R
Racemic
NA
NA
4819
NAd
4,097
564
628
4903
NA
1270
NA
10,080
1238
1480
NA
NA
NA
NA
625
163
200
12
13
497
NA
NA
NA
NA
11,927
5827
NA
NA
NA
2
>60
50
103
114
>20
NA
NA
>17
NA
11,120
NA
576
NA
a
b
c
Tested in triplicate, SEM generally 20%, on one occasion unless otherwise noted.
Tested on 3 different occasions.
Tested on 2 different occasions.
d
NA = IC50 > 10,000 nM.
11. Soth, M.; Hermann, J. C.; Yee, C.; Alam, M.; Barnett, J. W.; Berry, P.; Browner, M.
F.; Frank, K.; Frauchiger, S.; Harris, S.; He, Y.; Hekmat-Nejad, M.; Hendricks, T.;
Henningsen, R.; Hilgenkamp, R.; Ho, H.; Hoffman, A.; Hsu, P.-I.; Hu, D.-Q.; Itano,
A.; Jaime-Figueroa, S.; Jahangir, A.; Jin, S.; Kuglstatter, A.; Kutach, A. K.; Liao, C.;
Lynch, S.; Menke, J.; Niu, L.; Patel, V.; Railkar, A.; Roy, D.; Shao, A.; Shaw, D.;
Steiner, S.; Sun, Y.; Tan, S.-L.; Wang, S.; Vu, M. D. J. Med. Chem. 2013, 56, 345.
12. Lynch, S. M.; DeVicente, J.; Hermann, J. C.; Jaime-Figueroa, S.; Jin, S.;
Kuglstatter, A.; Li, H.; Lovey, A.; Menke, J.; Niu, L.; Patel, V.; Roy, D.; Soth, M.;
Steiner, S.; Tivitmahaisoon, P.; Vu, M. D.; Yee, C. Bioorg. Med. Chem. Lett. 2013,
23, 2793.
In summary, we have designed novel, potent anilino-indolylma-
leimide inhibitors of JAK3 based on a model constructed by super-
positioning of JAK3 inhibitor 5, a PKC inhibitor we found to have
JAK3 potency, and literature JAK3 selective inhibitors 3 and 4.
We developed the SAR with the aim of retaining JAK3 potency,
increasing JAK1 potency, and maintaining selectivity over JAK2
and TYK2. One compound, 11d (and eutomer 11e) demonstrated
good JAK3 potency as well as JAK2 and TYK2 selectivity similar
to lead compound 5. These compounds were not evaluated as
inhibitors for other kinases. Furthermore compound 11e, like 3,13
showed poor cellular activity (inhibition of STAT5 phosphorylation
induced by IL2 in CTLL cells, data not shown) providing further evi-
dence that JAK1 inhibition may be also required for therapeutic
intervention in RA. Since the potency of our series was modest
for JAK1 inhibition, we declined to pursue this series further.
13. Thoma, G.; Nuninger, F.; Falchetto, R.; Hermes, E.; Tavares, G. A.;
Vangrevelinghe, E.; Zerwes, H.-G. J. Med. Chem. 2011, 54, 284.
14. Labadie, S.; Dragovich, P. S.; Barrett, K.; Blair, W.; Bergeron, P.; Chang, C.;
Deshmukh, G.; Eigenbrot, C.; Ghilardi, N.; Gibbons, P.; Hurley, C. A.; Johnson,
A.; Kenny, J. R.; Kohli, P. B.; Kulagowski, J. J.; Liimatta, M.; Mendonca, R.;
Murray, J. M.; Pulk, R.; Shia, S.; Steffek, M.; Ubhayakar, S.; Ultsch, M.; van
Abbema, A.; Ward, S.; Zak, M. Bioorg. Med. Chem. Lett. 2012, 22, 7627.
15. Kulagowski, J. J.; Blair, W.; Bull, R. J.; Chang, C.; Deshmukh, G.; Dyke, H. J.;
Eigenbrot, C.; Ghilardi, N.; Gibbons, P.; Harrison, T. K.; Hewitt, P. R.; Liimatta,
M.; Hurley, C. A.; Johnson, A.; Johnson, T.; Kenny, J. R.; Kohli, P. B.; Maxey, R. J.;
Mendonca, R.; Mortara, K.; Murray, J.; Narukulla, R.; Shia, S.; Steffek, M.;
Ubhayakar, S.; Ultsch, M.; van Abbema, A.; Ward, S. I.; Waszkowycz, N.; Zak, M.
J. Med. Chem. 2012, 55, 5901.
References and notes
16. Zak, M.; Mendonca, R.; Balazs, M.; Barrett, K.; Bergeron, P.; Blair, W. S.; Chang,
C.; Deshmukh, G.; DeVoss, J.; Dragovich, P. S.; Eigenbrot, C.; Ghilardi, N.;
Gibbons, P.; Gradl, S.; Hamman, C.; Hanan, E. J.; Harstad, E.; Hewitt, P. R.;
Hurley, C. A.; Jin, T.; Johnson, A.; Johnson, T.; Kenny, J. R.; Koehler, M. F. T.;
Kohli, P. B.; Kulagowski, J. J.; Labadie, S.; Liao, J.; Liimatta, M.; Lin, Z.; Lupardus,
P. J.; Maxey, R. J.; Murray, J. M.; Pulk, R.; Rodriguez, M.; Savage, S.; Shia, S.;
Steffek, M.; Ubhayakar, S.; Ultsch, M.; van Abbema, A.; Ward, S. I.; Xiao, L.; Xiao,
Y. J. Med. Chem. 2012, 55, 6176.
17. Hurley, C. A.; Blair, W. S.; Bull, R. J.; Chang, C.; Crackett, P. H.; Deshmukh, G.;
Dyke, H. J.; Fong, R.; Ghilardi, N.; Gibbons, P.; Hewitt, P. R.; Johnson, A.;
Johnson, T.; Kenny, J. R.; Kohli, P. B.; Kulagowski, J. J.; Liimatta, M.; Lupardus, P.
J.; Maxey, R. J.; Mendonca, R.; Narukulla, R.; Pulk, R.; Ubhayakar, S.; van
Abbema, A.; Ward, S. I.; Waszkowycz, B.; Zak, M. Bioorg. Med. Chem. Lett. 2013,
23, 3592.
1. Fleischmann, R.; Kremer, J.; Cush, J.; Schulze-Koops, H.; Connell, C. A.; Bradley,
J. D.; Gruben, D.; Wallenstein, G. V.; Zwillich, S. H.; Kanik, S. K. N. Engl. J. Med.
2012, 367, 495.
2. van Vollenhoven, R.; Fleischmann, R.; Cohen, S.; Lee, E.; García Meijide, J. A.;
Wagner, S.; Forejtova, S.; Zwillich, S. H.; Gruben, D.; Koncz, T.; Wallenstein, G.
V.; Krishnaswami, S.; Bradley, J. D.; Wilkinson, B. N. Engl. J. Med. 2012, 367, 508.
3. van Vollenhoven, R. Curr. Opin. Rheumatol. 2013, 25, 391.
4. Flanagan, M. E.; Blumenkopf, T. A.; Brissette, W. H.; Brown, M. F.; Casavant, J.
M.; Shang-Poa, C.; Doty, J. L.; Elliott, E. A.; Fisher, M. B.; Hines, M.; Kent, C.;
Kudlacz, E. M.; Lillie, B. M.; Magnuson, K. S.; McCurdy, S. P.; Munchhof, M. J.;
Perry, B. D.; Sawyer, P. S.; Strelevitz, T. J.; Subramanyam, C.; Sun, J.; Whipple, D.
A.; Changelian, P. S. J. Med. Chem. 2010, 53, 8468.
5. Kontzias, A.; Kotlyar, A.; Laurence, A.; Changelian, P.; O’Shea, J. J. Curr. Opin.
Pharmacol. 2012, 12, 464.
6. O’Shea, J. J.; Pesu, M.; Borie, D. C.; Changelian, P. S. Nat. Rev. Drug Disc. 2004, 3,
555.
18. Malerich, J. P.; Lam, J. S.; Hart, B.; Fine, R. M.; Klebansky, B.; Tanga, M. J.;
D’Andrea, A. Bioorg. Med. Chem. Lett. 2010, 22, 7454.
19. Lim, J.; Taoka, B.; Otte, R. D.; Spencer, K.; Dinsmore, C. J.; Altman, M. D.; Chan,
C.; Rosenstein, C.; Sharma, S.; Su, H.-P.; Szewczak, A. A.; Xu, L.; Yin, H.; Zugay-
Murphy, J.; Marshall, C. G.; Young, J. R. J. Med. Chem. 2011, 54, 7334.
20. Schenkel, L. B.; Huang, X.; Cheng, A.; Deak, H. L.; Doherty, E.; Emkey, R.; Gu, Y.;
Gunaydin, H.; Kim, J. L.; Lee, J.; Loberg, R.; Olivieri, P.; Pistillo, J.; Tang, J.; Wan,
Q.; Wang, H.-L.; Wang, S.-W.; Wells, M. C.; Wu, B.; Yu, V.; Liu, L.; Geuns-Meyer,
S. J. Med. Chem. 2011, 54, 8440.
21. Anastassiadis, T.; Deacon, S. W.; Devarajan, K.; Ma, H.; Peterson, J. R. Nat.
Biotechnol. 2011, 29, 1039.
22. Tanaka, M.; Sagawa, S.; Hoshi, J.-I.; Shimoma, F.; Matsuda, I.; Sakoda, K.; Sasase,
T.; Shindo, M.; Inaba, T. Bioorg. Med. Chem. Lett. 2004, 14, 5171.
7. Lin, T. H.; Hegen, M.; Quadros, E.; Nickerson-Nutter, C. L.; Appell, K. C.; Cole, A.
G.; Shao, Y.; Tam, S.; Ohlmeyer, M.; Wang, B.; Goodwin, D. G.; Kimble, E. F.;
Quintero, J.; Gao, M.; Symanowicz, P.; Wrocklage, C.; Lussier, J.; Schelling, S. H.;
Hewet, A. G.; Xuan, D.; Krykbaev, R.; Togias, J.; Xu, X.; Harrison, R.; Mansour, T.;
Collins, M.; Clark, J. D.; Webb, M. L.; Seidl, K. J. Arthritis Rheum. 2010, 62, 2283.
8. Haan, C.; Rolvering, C.; Raulf, F.; Kapp, M.; Druckes, P.; Thoma, G.; Behrmann, I.;
Zerwes, H.-G. Chem. Biol. 2011, 18, 314.
9. Clark, M. P.; George, K. M.; Bookland, R. G.; Chen, J.; Laughlin, S. K.; Thakur, K.
D.; Lee, W.; Davis, J. R.; Cabrera, E. J.; Brugel, T. A.; VanRens, J. C.; Laufersweiler,
M. J.; Maier, J. A.; Sabat, M. P.; Golebiowski, A.; Easwaran, V.; Webster, M. E.;
Dea, B.; Zhang, G. Bioorg. Med. Chem. Lett. 2007, 17, 1250.
23. Schlosser, M.; Bobbio, C.; Rausis, T. J. Org. Chem. 2005, 70, 2494.
24. Wendt, M. D.; Kunzer, A. R. Tetrahedron Lett. 2010, 51, 641.
25. Shafir, A.; Lichtor, P. A.; Buchwald, S. L. J. Am. Chem. Soc. 2007, 129, 3490.
10. Jaime-Figueroa, S.; De Vicente, J.; Hermann, J.; Jahangir, A.; Jin, S.; Kuglstatter,
A.; Lynch, S. M.; Menke, J.; Niu, L.; Patel, V.; Shao, A.; Soth, M.; Vu, M. D.; Yee, C.
Bioorg. Med. Chem. Lett. 2013, 23, 2522.

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1121
26. (S)-3-{3-[1-(2-Fluoro-pyridin-4-yl)-pyrrolidin-3-yloxy]-phenylamino}-4-(1H-
indol-3-yl)-pyrrole-2,5-dione (11e). (a) (S)-pyrrolidin-3-ol, 22, (500 mg,
5.75 mmol), 2,4-difluoropyridine (793 mg, 6.9 mmol) and DIPEA (0.5 mL) in
DMF (5 mL) was heated at 60 °C for 20 h. The mixture was poured into 1 N
NaOH solution (100 mL), extracted with ethyl acetate (2X). Combined extracts
were washed with brine, dried over magnesium sulfate, and concentrated to
give (S)-1-(4-fluoropyridin-2-yl)pyrrolidin-3-ol 23 (512 mg, 49% yield). (b) A
mixture of 23 (91.5 mg, 0.5 mmol), 1-iodo-3-nitrobenzene (162 mg,
0.65 mmol), CuI (10 mg, 0.052 mmol), cesium carbonate (328 mg, 1.0 mmol)
and 3,4,7,8-tetramethyl-1,10-phenanthroline (24 mg, 0.1 mmol) in THF
(0.5 mL) was heated at 100 °C for 18 h. To the reaction mixture was added
20 mL of water and 20 mL of ethyl acetate. The resulting mixture was filtered
through celite. The filtrate was separated; the aqueous layer was extracted
with ethyl acetate (2ꢀ). Combined organic layers were washed with brine,
dried over magnesium sulfate, and concentrated. The residue was purified by
normal phase flash chromatography (40–60% ethyl acetate/hexanes) and 4-
((S)-3-(3-nitrophenoxy)pyrrolidin-1-yl)-2-fluoropyridine (40 mg, 26% yield)
was used in the next step. The compound (75 mg, 0.247 mmol), and Pd/C
(10%, 100 mg) in ethanol (5 mL) was hydrogenated at 40 psi for 2 h. Then the
catalyst was removed by filtration. The filtrate was evaporated was evaporated
to give 3-((S)-1-(2-fluoropyridin-4-yl)pyrrolidin-3-yloxy)benzenamine 14v
(61 mg, 90% yield). (c) The mixture of 14v (60 mg, 0.22 mmol) and 3-
hydroxy-4-(1H-indol-3-yl)-1H-pyrrole-2,5-dione (13) (16.7 mg, 0.073 mmol)
in acetic acid (0.25 mL) was stirred at RT for 0.5 h, then heated at 100 °C for 3 h.
The reaction mixture was diluted with 1 mL DMF, filtered, and the filtrate was
purified by reverse phase chromatography to afford 11e (59 mg, 55% yield): 1
H
NMR (300 MHz, DMSO-d6) d 11.29 (d, J = 2.6 Hz, 1H), 10.69 (s, 1H), 9.12 (s, 1H),
7.76 (d, J = 5.9 Hz, 1H), 7.38 (d, J = 7.9 Hz, 1H), 7.28 (d, J = 8.1 Hz, 1H), 7.05 (d,
J = 2.6 Hz, 1H), 6.98 (t, J = 7.6 Hz, 1H), 6.84 (dt, J = 21.5, 7.8 Hz, 2H), 6.63 (d,
J = 8.5 Hz, 1H), 6.42–6.35 (m, 1H), 6.26 (dd, J = 7.8, 2.3 Hz, 1H), 6.11–6.02 (m,
2H), 4.02 (s, 1H), 3.25 (m, 2H), 3.19–3.00 (m, 2H), 1.89–1.62 (m, 2H). Mass (CI):
C27H22FN5O3; Calcd Mass: 483.17, Found: 484.20 (M+1).