Discovery of 3,5-substituted 6-azaindazoles as potent pan-Pim inhibitors

Article abstract of DOI:10.1016/j.bmcl.2015.09.052

Pim kinase inhibitors are promising cancer therapeutics. Pim-2, among the three Pim isoforms, plays a critical role in multiple myeloma yet inhibition of Pim-2 is challenging due to its high affinity for ATP. A co-crystal structure of a screening hit 1 bound to Pim-1 kinase revealed the key binding interactions of its indazole core within the ATP binding site. Screening of analogous core fragments afforded 1H-pyrazolo[3,4-c]pyridine (6-azaindazole) as a core for the development of pan-Pim inhibitors. Fragment and structure based drug design led to identification of the series with picomolar biochemical potency against all three Pim isoforms. Desirable cellular potency was also achieved.

Full text of DOI:10.1016/j.bmcl.2015.09.052

Accepted Manuscript
Discovery of 3,5-substituted 6-azaindazoles as potent pan-Pim inhibitors
Huiyong Hu, Xiaojing Wang, Grace Ka Yan Chan, Jae H. Chang, Steven Do,
Jake Drummond, Allen Ebens, Wendy Lee, Justin Ly, Joseph P. Lyssikatos,
Jeremy Murray, John G. Moffat, Qi Chao, Vickie Tsui, Heidi Wallweber,
Aleksandr Kolesnikov
PII:
S0960-894X(15)30086-X
http://dx.doi.org/10.1016/j.bmcl.2015.09.052
BMCL 23133
DOI:
Reference:
Bioorganic & Medicinal Chemistry Letters
To appear in:
Received Date:
Revised Date:
Accepted Date:
24 June 2015
10 September 2015
22 September 2015
Please cite this article as: Hu, H., Wang, X., Chan, G.K.Y., Chang, J.H., Do, S., Drummond, J., Ebens, A., Lee, W.,
Ly, J., Lyssikatos, J.P., Murray, J., Moffat, J.G., Chao, Q., Tsui, V., Wallweber, H., Kolesnikov, A., Discovery of
3,5-substituted 6-azaindazoles as potent pan-Pim inhibitors, Bioorganic & Medicinal Chemistry Letters (2015), doi:
http://dx.doi.org/10.1016/j.bmcl.2015.09.052
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Bioorganic & Medicinal Chemistry Letters
Discovery of 3,5-substituted 6-azaindazoles as potent pan-Pim inhibitors
Huiyong Hu a, Xiaojing Wang a, Grace Ka Yan Chan a, Jae H. Chang a, Steven Do a, Jake Drummond a, Allen Ebens b, Wendy Lee a, Justin Ly a, Joseph P.
Lyssikatos c, Jeremy Murray a, John G. Moffat a, Qi Chaod, Vickie Tsui a, Heidi Wallweber a, Aleksandr Kolesnikov* a
aGenentech, Inc., 1 DNA Way, South San Francisco, California 94080, United States.
b Juno Therapeutics, 307 Westlake Ave North, Seattle Washington 98109, United States
c Biogen Idec, 12 Cambridge Center, Cambridge, Massachusetts, 02142, United States
d BioMarin (Shanghai), Room 605 780 Cailun Road, Pudong District, Shanghai 201203
ARTICLE INFO
ABSTRACT
Article history:
Received
Revised
Accepted
Available online
Pim kinase inhibitors are promising cancer therapeutics. Pim-2, among the three Pim isoforms,
plays a critical role in multiple myeloma yet inhibition of Pim-2 is challenging due to its high
affinity for ATP. A co-crystal structure of a screening hit 1 bound to Pim-1 kinase revealed the
key binding interactions of its indazole core within the ATP binding site. Screening of
analogous core fragments afforded 1H-pyrazolo[3,4-c]pyridine (6-azaindazole) as a core for the
development of pan-Pim inhibitors. Fragment and structure based drug design led to
identification of the series with picomolar biochemical potency against all three Pim isoforms.
Desirable cellular potency was also achieved.
Keywords:
Pim kinases
Kinase inhibitor
Screening
2015 Elsevier Ltd. All rights reserved.
Fragment based screen
Structure based drug design
Lead optimization
Pim (Proviral Insertion site for Moloney murine lymphomia virus) kinases are a family of three constitutively active, functionally
related oncogenic serine/threonine protein kinases encoded by the genes pim-1, pim-2, and pim-3.1 Pim overexpression has been
observed in many cancers, and Pim kinases have drawn increased attention as promising targets for oncology drug therapeutics. 2
Reports on many pan Pim or Pim-1,3 selective inhibitors have been published recently.3 Various studies have shown that,
among the three Pim isoforms, Pim-2 expression is prevalent and highly critical to the growth and survival of multiple myeloma
cancer cells,4 yet inhibition of Pim-2 with an adenosine triphosphate (ATP) competitive Pim-2 inhibitor is challenging due to the
high binding affinity of Pim-2 kinase to ATP.5 We have previously reported the discovery of pyrazolo[1,5-a]pyrimidines as
potent pan-Pim inhibitors achieving picomolar potencies against all three Pim kinases.6 In this letter we report 1H-pyrazolo[3,4-
c]pyridines as a distinct series with high pan-Pim inhibitory activities and moderate to high metabolic stability in vivo.
Pim-1 Ki = 14 nM, LE = 0.38, LipE = 3.9
Pim-2 Ki = 8.7 nM, LE = 0.38, LipE = 4.1
Pim-3 Ki = 17 nM, LE = 0.36, LipE = 3.8

Figure1. X-ray co-crystal structure of 1 bound to Pim-1(PDB-ID 5DGZ).
The ATP binding site of PIM-1 is illustrated with compound 1 shown as cyan sticks, and the 2.5 Å resolution 2Fo-Fc electron
density for compound 1 is represented as blue mesh contoured at 1sigma. Water molecules are represented as red spheres,
hydrogen bond interactions between 1 and the protein are represented as black dashes. Important regions of the active site that
are referred to in the text are labeled and the residues are shown as green sticks.
Screening of our internal compound collection identified indazole 1, a known Akt inhibitor,7 as a pan-Pim inhibitor with
moderate potency. Having moderate LE8 and LipE (calculated with cLogP values),9 compound 1 is equally potent for all three
Pim isoforms. This was of particular interest because for the majority of scaffolds investigated, the inhibitory activity was
often10-fold less for Pim-2 than for Pim-1 or Pim-36. The X-ray co-crystal structure of 1 bound to full length Pim-1 (Figure 1)
revealed several polar interactions in the ATP binding site including a single hydrogen bond interaction with the hinge residue
Glu121, a contact of the pyridine nitrogen with the catalytic Lys67, and multiple interactions of the primary amine with Glu171,
Asn172, and Asp186 (directly or through a conserved water). The benzene portion of the indole end group is exposed to the
solvent front.

Table 1
Optimization of core motif based on compound 1
Ki a (µM)
(LipE b)
ID
Pim-1
Pim-2
Pim-3
1.3
(4.2)
6
(3.5)
1.8
(4.0)
2
3.3
(5.3)
15
(4.6)
2.9
(5.3)
3
4
5
6
7
0.2
(4.9)
0.8
(4.3)
0.3
(4.7)
0.8
(3.8)
3.9
(3.1)
1.5
(3.5)
0.3
(5.2)
0.9
(4.7)
0.4
(5.1)
3.2
(3.3)
2.7
(3.4)
3.1
(3.3)
0.01
(4.7)
0.05
(4.0)
0.005
(5.0)
8
9
0.01
(5.5)
0.07
(4.7)
no
data
a Biochemical assay. b LipE = -log(Ki in molar) – cLogP.
Given the lead molecule 1 has a fairly extended structure we decided to pursue a fragment approach based on monitoring
changes in LipE. Starting from the indazole core of compound 1 (Fig. 1, in blue), we first made compound 2 (Table 1) with a
nitrogen at the 6-position replacing the corresponding carbon in compound 1. We hypothesized that incorporation of a nitrogen at
the 6-position may establish a new hydrogen bond with a stable water observed in the vicinity.6 Fragment 2 maintains decent
LipE comparable to compound 1 despite significant loss in potency. In order to reduce the number of aromatic rings for potential
solubility gain, we also designed fragment 3 with an amide group replacing the fused pyridine moiety. Despite a 2-fold decrease
in potency from compound 2 to 3, lipophilic efficiency increases for the latter. Unfortunately, attempted potency gains based on
fragment 3 proved to be elusive. Adding back a methyl group at C(3) of 2, i.e. compound 4, proved to be beneficial increasing

both potency by 6-fold and LipE. To probe the importance of N(2) in azaindazole 4, fragment 5 containing an azaindole core was
made. The decreased potency is hard to explain considering the lack of hydrogen bond donor in the PIM-specific proline residue
at the hinge to interact with N(2) of an azaindazole. However, similar structure activity relationship was seen with another
scaffold we disclosed recently.6 Replacing the pyridin-3’-yl head group at C(5) of 2 with a pyrazol-4’-yl moiety (compound 6)
proved to be a viable change resulting in similar potency and increased LipE. Comparing with compound 7, N(6) in compound 6
is accountable for 3- to 10-fold potency improvement and drastically increased LipE. This observation validated our initial
hypothesis of the benefit from an additional hydrogen bond to a conserved molecule of water. Following a potency boost by
addition of a lipophilic methyl group at position 3 (e.g. compound 4), further replacement with a phenyl or pyridin-2-yl group
resulted in more than 100-fold potency improvement with concurrent LipE increase (compounds 2 vs. 8 and 9). In summary, the
novel 6-azaindazole core, as shown in 2, 4, 6, 8 and 9 with improved LipE in most cases provided a good starting point for
further optimization.
Figure2. X-ray crystal structure of PIM1 in complex with 4 (PDB-ID 5DHJ).
The ATP binding site of PIM1 is illustrated with compound 4 shown as salmon colored sticks, and the 2.46 Å resolution 2Fo-Fc
electron density for 4 is represented as blue mesh contoured at 1sigma.
The X-ray co-crystal structure of compound 4 bound to Pim-1 and the key binding interactions of the fragment within the ATP
binding pocket are illustrated in Figure 2. This includes hydrogen bonds between 1H and Glu121 at the hinge, N(6) and the
adjacent conserved water W1 (3.1 Å) found in the kinase specificity pocket, finally N(3’) and catalytic Lys67 of the backbone.
Typical for Pim kinases are an abundant number of acidic residues (in this case are Asp128, Asn142, and Glu171) in the C-
terminus; hence, this area is also referred to as the acidic patch. It is postulated that the acidic patch could be approached from
two directions by basic moieties projecting from either the C(3) of the 1H-pyrazolo[3,4-c]pyridine core, or C(5’) or C(6’) of the
5-pyridinyl ring.

Table 2
Assembling 5-(Heteroaryl)-lH-pyrazolo[3,4-c]pyridine derivatives from three directions
Ki a (µM)
(LipE b)
Ki (µM)
(LipE)
ID
ID
Pim-1
Pim-2
Pim-3
Pim-1
Pim-2
Pim-3
0.2
(4.9)
0.8
(4.3)
0.3
(4.7)
0.006
(6.7)
0.17
(5.3)
0.009
(6.6)
4
13
3.5
(3.5)
8.3
(3.1)
5
(3.3)
0.0001
(6.8)
0.003
(5.3)
0.0001
(6.9)
10
14
0.014
(4.2)
0.035
(3.9)
0.006
(4.6)
0.0003
(7.6)
0.003
(6.6)
0.0002
(7.9)
11
15
0.0034 0.0017 0.00011
(6.0) (5.3) (6.5)
0.00004 0.0005 0.00001
(8.1) (7.0) (8.7)
12
16
a, b As in Table 1.
Even though compound 10 can be modeled such that the basic amine reaches the acidic patch (data not shown), this compound
incurred significant potency and LipE loss. This is likely because the piperidine ring would need to be co-planar with the
pyridine in order for the salt bridge to acidic residues to form, whereas an orthogonal conformation that does not fit in the narrow
pocket would be preferred in solution. The next step was an addition of a hydrophobic 2’-fluorophenyl group at C(3) in
compound 11 which caused a significant potency gain with improvement in LipE. Insertion of an oxygen spacer at C(6’), i.e.
compound 12, gave rise to further potency gains, this time likely due to a preference to adopt co-planar geometry in solution.
Compounds 13 and 14 approach the acidic patch from a different position (C(3’) of the 5-pyrazine-2’-yl ring). Such analogs
retained planarity of the scaffold, and good potency was achieved with picomolar Ki’s for Pim-1 and Pim-3, and single-digit
nanomolar Ki for Pim-2, as exemplified by 14.11 Compounds 15 and 16 interact with the acidic patch from the opposite side of

the core. Compound 15 with a flexible amino group bearing chain is equipotent to compound 14 yet shows improved LipE for all
Pim isoforms, indicating the promise of utilizing the 2-pyridine as a spacer group. Restraining the flexibility of a basic amine in
compound 16 resulted in further improvement in potency. For the first time, subnanomolar Ki was achieved for Pim-2 in the 6-
azaindazole series, prompting us to focus our efforts on expanding SAR for the series.

Table 3
Probing catalytic Lysine interactions
Ki a (nM)
Ki (nM)
(LipE)
(LipEb)
ID
17
18
19
R
ID
24
25
26
R
Pim-1
Pim-2
Pim-3
Pim-1
Pim-2
Pim-3
0.041
(7.6)
0.30
(6.7)
0.037
(7.6)
171
(6.8)
1100
(6.0)
115
(7.0)
0.010
(9.2)
0.049
(8.5)
0.010
(9.2)
2.0
(7.7)
1.1
(8.0)
0.68
(8.2)
0.015
(10.5)
0.145
(9.5)
0.070
(10.9)
31
(6.4)
33
(6.4)
3.3
(7.4)
0.036
(8.5)
0.58
(7.3)
0.017
(8.9)
8.5
(6.6)
82
(5.6)
no data
(no data)
20
21
22
23
27
28
29
30
0.022
(9.2)
0.127
(8.4)
0.013
(9.4)
4.0
(6.5)
26
(5.7)
1.0
(7.1)
0.021
(8.0)
0.253
(6.9)
0.016
(8.1)
13
(7.3)
17
(7.2)
1.4
(8.3)
1.82
(7.1)
5.4
(6.7)
0.65
(7.6)
3.3
(6.9)
14
(6.3)
4.4
(6.8)
a As in Table 1.
A variety of head groups aimed to form polar interactions with Lys67 have been tested (Table 3). Substituents at C(5’) of the 5-
pyridine-3’-yl ring are tolerated as shown in compound 17, which is equipotent to its unsubstituted counterpart 16. The presence
of a second nitrogen, i.e. N(2’) in 6’-methylpyrazine-2-yl (compound 18), was hypothesized to restrict the rotation of pyrazine-
azaindazole bond and maintain a more preferable biologically active conformation. Indeed, excellent picomolar potency was
achieved for all three Pim kinases. The same consideration can be applied to compound 19 containing hydrophilic pyrimidinone
group and showing highest LipE in the series. A variety of substituents attached to the second nitrogen of the pyrazole head
group (compounds 20- 22) are tolerated, providing a handle for adjusting physicochemical properties of the compounds.

Attempt to replace pyrazole with imidazole led to a significant loss of potency in compound 23 presumably due to a
combination of losing the methyl group, which has van der Waals interaction with Phe49, and different charge distributions
caused by the heterocycles (Figure 1S in Supplemental Materials) whose exact contributions to potency are unknown.
Compound 24 bearing aliphatic amide as a head group has much reduced potency (Ki in the micromolar range for Pim-2). When
the alkyl amide group is replaced by the corresponding urea in compound 25, the potency was restored to the low nanomolar
range possibly due to an internal hydrogen bond formation placing the carbonyl closer toward the catalytic lysine. Our further
attempts to utilize oxygen as the hydrogen bond acceptor were not successful. Compounds with a head group such as
imidazolidindione (compound 26), tetrahydrofuran or tetrahydropyran (compounds 27 and 28, respectively), piperazinone
(compound 29), and morpholine (compound 30) are all not well tolerated. In general, heteroaromatic head groups proved to be
beneficial for potency, and therefore N-methylpyrazolyl group at C(5) was selected to explore structure-activity relationship
by varying amino-bearing groups connected to C(3) of the core and interacting with the acidic patch (Table 4)

Table 4
Exploring basic groups to access the acidic patch.
Ki a (nM)
(LipEb)
Ki (nM)
(LipE)
ID
R
ID
R
Pim-1
Pim-2
Pim-3
Pim-1
Pim-2
Pim-3
7.7
(6.2)
48
(5.4)
3.7
(6.5)
0.14
(7.8)
0.72
(7.0)
0.021
(8.6)
31
35
0.036
(8.5)
0.58
(7.3)
0.017
(8.9)
0.035
(8.0)
0.43
(6.9)
0.015
(8.3)
20
36
0.020
(7.9)
0.17
(7.0)
0.013
(8.1)
0.060
(7.7)
0.26
(7.1)
0.015
(8.3)
32
33
37
38
0.22
(7.4)
2.2
(6.5)
0.12
(7.7)
0.39
(6.3)
1.25
(4.8)
0.29
(6.4)
0.27
(6.8)
6.2
(5.4)
0.16
(7.0)
0.013
(7.9)
0.088
(7.1)
0.006
(8.2)
34
39
a As in Table 1.
Different substitutions at C(3’) off the pyridine ring via linkers such as nitrogen, carbon or oxygen were studied. Compound 20
with piperazine moiety at C(3’) is 80 to 200-fold more potent than compound 31 without any substitution. Homopiperazine
derivative 32 is slightly more potent, yet has lower LipE value indicating improved potency is driven mostly likely by increased
lipophilicity. The carbon linked compound 33, however, is 4- to 7-fold less active than compound 20. It is likely due to a
conformational change caused by the sp3-hybridized carbon attached to C(3’), resulting in a shift of the basic amine away from
the acidic patch. Similarly, compound 34 with an oxygen linker may have lost potency relative to the nitrogen linker due to

differences in preferred conformations driven by dipole-dipole interaction between oxygen linker and pyridine nitrogen. In order
to optimize the interaction with the acidic patch, primary amines were also investigated. For example, compounds 35 and 36
contain primary amines linked by a five- and six-membered heterocyclic ring, respectively. Both ring sizes are tolerated, while
the six-membered ring is more favorable for potency. Equal potency of enantiomers 36 and 37 shows the ability of the acidic
patch to accommodate both. The importance of the nature of the spacer between the core and a basic amine bearing group is
clearly demonstrated by the difference in potency between compounds 36 and 38. While compound 36 contains a pyridinyl
moiety constrained by intramolecular interactions to prefer the bound conformation, free rotation of the benzene ring in
compound 38 gives likely no statistical preference for a bioactive conformation and resulted in a drop of potency. The
installation of methyl group at the C(4’) position of the pyridine ring in compound 39 was aimed to further enforce an orthogonal
orientation of the piperidine ring, consequently positioning a primary amine in the vicinity of the acidic patch. As a result, 2- to
4-fold potency improvement was observed from compound 37 to 39, accompanied by small increase in LipE value for Pim-1.
In general, it is worth noting that high LipE values (> 7 for Pim-2 and > 7.5 for Pim-1 and Pim-3) were consistently observed
within the basic amine containing subseries, such as compounds 16, 20, 32, 35-37 and 39.
Figure 3. X-ray crystal structure of PIM1 in complex with compound 36 (PDB-ID 5DIA).
The ATP binding site of PIM1 is illustrated with compound 36 shown as orange colored sticks, and the 1.9 Å resolution 2Fo-Fc
electron density for 36 is represented as blue mesh contoured at 1sigma.
Shown in Figure 3 is the X-ray co-crystal structure of compound 36 bound to Pim-1. As expected, a hydrogen bond was seen
between the carbonyl oxygen of hinge residue Glu121 and 1H of the 6-azaindazole core. N(6) of the core acted as an acceptor to
form a hydrogen bond with adjacent molecule of water (3.0 Å). A third hydrogen bond was observed between N(4’) of the
pyrazole and Lys67. The basic amine formed one direct salt bridge to the acidic residue and additional hydrogen bonds with
water molecules simultaneously.

Table 5
Profile of compound 40
Pim-1 Ki = 0.073 nM
Pim-2 Ki = 0.473 nM
Pim-3 Ki = 0.041 nM
Cellular Potency IC50 (µM)
ADME Properties (Rat)
f
g
Ratio a
MM1.s CLp b
0.64 14
%F c %PPB d RLM CLint e
MDCKA-B
MDCK ratio
BaF3_IL3 BaF3_Pim
5.4 0.077
70
1
97.8
150
0.5
51
a Ratio = BaF3_IL3 IC50/BaF3_Pim-1 IC50. b CLp=in vivo plasma clearance (mL/min/kg). c Oral bioavailability. d Plasma Protein
Binding. e CLint=intrinsic clearance from rat liver microsomes (mL/min/kg). Apparent permeability (x10-6cm/sec). g MDCK
f
ratio = B-A/A-B.
After triaging compounds through the testing cascade, compound 40 (Table 5) provided the most balanced profile in terms of
potency and stability in vivo as one of the lead compounds of the series. It shows double-digit nanomolar potency when tested
for cell-killing activity against PIM1-transfected BaF3 myeloid cells, whose survival in the absence of added IL-3 is Pim-1
dependent. However, it is not potent against the parental BaF3 cell line, whose growth and survival is dependent on IL-3 but
independent of Pim kinase functions. The cellular potency (IC50) ratio between these cell lines is about 70-fold, demonstrating
the absence of non-selective cytotoxicity. Compound 40 has also potent antiproliferative activity against the MM1.S multiple
myeloma cell line, with IC50 of 0.64 µM. Despite low total clearance the poor bioavailability of compound 40 has likely resulted
from poor permeability (indicated by the MDCK measurements) and possibly high intestinal metabolism. This liability
prompted us to design another series of analogs solving this type of metabolism issues, which will be reported in due time.
Scheme 1. Synthesis of 40

a Reagents and conditions: (i) Zn, NH4Cl, EtOH, water, rt (60%); (ii) NaNO2, AcOH, 0 °C to rt (73%); (iii) N-iodosuccinimide,
DMF, 0 °C to rt (85%); (iv) DHP, p-TSA, CH2Cl2, 24h (67%); (v) 2-fluoro-6-(tributylstannyl)pyridine, Pd(PPh3)4, toluene, 110
°C, 3h (84%); (vi) 1-ethyl-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrazole, Pd(PPh3)2Cl2, Na2CO3, 1,4-dioxane,
reflux (80%); (vii) Boc-piperazine, DMSO, 105 °C, 48h, (95%); (vii) 4M HCl in 1,4-dioxane, MeOH, rt (85%).
The synthesis of 6-azaindazole analogs is exemplified in Scheme 1.12 Zinc reduction of the nitro group of compound 41 afforded
amine 42. Treating 42 with sodium nitrite in acetic acid led to the formation of 6-azaindazole 43, which was iodinated and then
protected by THP group to afford 44. Stille coupling between 44 and 2-fluoro-6-(tributylstannyl)pyridine provided key
intermediate 45. Suzuki coupling between bromide 45 and aryl boronic acid or boronate (exemplified by 1-ethyl-4-(4,4,5,5-
tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrazole in Scheme 1) afforded 46. Subsequent SnAr displacement with various
monoprotected diamines (exemplified by Boc-piperazine in Scheme 1) followed by acidic deprotection yielded final compounds
represented by 40 in Scheme 1.
In summary, based on the X-ray co-crystal structure of the screening hit 1 with Pim-1, an indazole core was identified as the
starting point. A fragment based approach to screen similar fragments afforded 6-azaindazoles as one of the desirable cores.
Further optimizations yielded analogs with picomolar biochemical potency against all three Pim kinases, resulting in good
cellular potency. Poor pharmacokinetic properties for the 6-azaindazole series prompted us to design alternative Pim inhibitors
that successfully solved the problems. We will report the improved series in due time.
Acknowledgments
We are grateful to analytical, purification chemistry and compound management group for compound characterization,
purification and handling. Thanks to Vivienne Allen for the conformational analysis.
Melief, C.; Berns, A. Cell 1984, 37, 141; (b) Selten, G.;
Cuypers, H. T.; Berns, A. EMBO J. 1985, 4, 1793; (c)
van Lohuizen, M.; Verbeek, S.; Scheijen, B.; Wientjens,
E.; van der Gulden, H.; Berns, A. Cell 1991, 65, 737.
References and notes
1. (a) Cuypers, H. T.; Selten, G.; Quint, W.; Zijlstra, M.;
Maandag, E. R.; Boelens, W.; van Wezenbeek, P.;

2. (a) Magnuson, N. S.; Wang, Z.; Ding, G.; Reeves, R.
Future Oncol. 2010, 6, 1461-1478; (b) Merkel, A. L.;
Meggers, E.; Ocker, M. Expert Opin. Investig. Drugs
2012, 21, 425.
M. R.; Mohr, C.; Andrews, K. L.; Tasker, A. S. Bioorg.
Med. Chem. Lett. 2015, 25, 775.
4. (a) Munugalavadla, V.; Berry, L.; Chen, Y.-H.;
Deshmukh, G.; Drummond, J.; Du, C.; Eby, M.;
Fitzgerald, K.; Friedman, L. S.; Gould, S. E.; Kenny, J.
R.; Maecker, H.; Moffat, J.; Moskalenko, M.; Pacheco,
P.; Saadat, A.; Slaga, D.; Sun, L.; Wang, X.; Yang, Y.;
Ebens, A. J. Blood 2010, 116, 4084; (b) Ebens, A. J.;
Berry, L.; Chen, Y.-H.; Deshmukh, G.; Drummond, J.;
Du, C.; Eby, M.; Fitzgerald, K.; Friedman, L. S.; Gould,
S. E.; Kenny, J. R.; Maecker, H.; Moffat, J.; Moskalenko,
M.; Pacheco, P.; Saadat, A.; Slaga, D.; Sun, L.; Wang,
X.; Yang, Y.; Munugalavadla, V. Blood 2010, 116, 3001;
(c) Drygin, D.; Haddach, M.; Pierre, F.; Ryckman, D. M.
J. Med. Chem. 2012, 55, 8199; (d) Anizon, F. S., Shtil, A.
A.; Danilenko, V.N.; Moreau, P. Curr. Med. Chem. 2010,
17, 4114; (e) Morwick, T. Expert Opin. Ther. Pat. 2010,
20, 193.
5. Garcia, P. D.; Langowski,J. L.; Wang, Y; Chen M.,
Castillo J.; Fanton, C.; Ison, M; Zavorotinskaya,T.; Dai,
Y.; Lu, J.; Niu, X-H.; Basham, S.; Chan, J; Yu, J.; Doyle,
M.; Feucht, P.; Warne, R.; Narberes, J.; Tsang, T.;
Fritsch, C.; Kauffmann, A.; Pfister, E.; Drueckes, P.;
Trappe, J.; Wilson, C.; Han, W.; Lan, J.; Nishiguchi,G.;
Lindvall, M.; Bellamacina, C.; Alex Aycinena, J.; Zang,
R.; Holash, J.; Matthew T. Burger, M. T. Clin. Cancer
Res. 2014, 20, 1834.
3. (a) Tao, Z.-F.; Hasvold, L. A.; Leverson, J. D.; Han, E.
K.; Guan, R.; Johnson, E. F.; Stoll, V. S.; Stewart, K. D.;
Stamper, G.; Soni, N.; Bouska, J. J.; Luo, Y.; Sowin, T.
J.; Lin, N.-H.; Giranda, V. S.; Rosenberg, S. H.; Penning,
T. D. J. Med. Chem. 2009, 52, 6621; (b) Pastor, J.;
Oyarzabal, J.; Saluste, G.; Alvarez, R. M.; Rivero, V.;
Ramos, F.; Cendon, E.; Blanco-Aparicio, C.; Ajenjo, N.;
Cebria, A.; Albarran, M. I.; Cebrian, D.; Corrionero, A.;
Fominaya, J.; Montoya, G.; Mazzorana, M. Bioorg. Med.
Chem. Lett. 2012, 22, 1591; (c) Tsuhako, A. L.; Brown,
D. S.; Koltun, E. S.; Aay, N.; Arcalas, A.; Chan, V.; Du,
H.; Engst, S.; Franzini, M.; Galan, A.; Huang, P.;
Johnston, S.; Kane, B.; Kim, M. H.; Laird, A. D.; Lin, R.;
Mock, L.; Ngan, I.; Pack, M.; Stott, G.; Stout, T. J.; Yu,
P.; Zaharia, C.; Zhang, W.; Zhou, P.; Nuss, J. M.;
Kearney, P. C.; Xu, W. Bioorg. Med. Chem. Lett. 2012,
22, 3732; (d) Xiang, Y.; Hirth, B.; Asmussen, G.;
Biemann, H.-P.; Bishop, K. A.; Good, A.; Fitzgerald, M.;
Gladysheva, T.; Jain, A.; Jancsics, K.; Liu, J.; Metz, M.;
Papoulis, A.; Skerlj, R.; Stepp, J. D.; Wei, R. R. Bioorg.
Med. Chem. Lett. 2011, 21, 3050; (e) Dakin, L. A.;
Block, M. H.; Chen, H.; Code, E.; Dowling, J. E.; Feng,
X.; Ferguson, A. D.; Green, I.; Hird, A. W.; Howard, T.;
Keeton, E. K.; Lamb, M. L.; Lyne, P. D.; Pollard, H.;
Read, J.; Wu, A. J.; Zhang, T.; Zheng, X. Bioorg. Med.
Chem. Lett. 2012, 22, 4599; (f) Burger, M. T.; Han W.;
Lan, J.; Naguchi, G.; Bellamacina, C.; Lindval, M.;
Atallah, G.; Ding, Y.; Mathur, M.; McBride, C.; Beans,
E. L.; Muller, K.; Tamez, V.; Zhang, Y.; Huh, K.; Feucht,
P.; Zavorotinskaya, T.; Dai, Y.; Holash, J.; Castillo, J.;
Langowski J., Wang Y.; Chen M. Y.; Garcia P. ACS
Med. Chem. 2013, 4, 1193; (g) Casuscelli, F.; Ardini, E.;
Avanzi, N.; Casale, E.; Cervi, G.; D'Anello, M.; Donati,
D.; Faiardi, D.; Ferguson, R. D.; Fogliatto, G.; Galvani,
A.; Marsiglio, A.; Mirizzi, D. G.; Montemartini, M.;
Orrenius, C.; Papeo, G.; Piutti, C.; Salom, B.; Felder, E.
R. Bioorg. Med. Chem. Lett. 2013, 21, 7364; (h) Dwyer,
Michael M. P.; Keertikar, K.; Paruch, K.; Alvarez, C.;
Labroli, M.; Poker, C.; Fischmann, T. O.; Mayer-Ezell,
R.; Bond, R.; Wang, Y.; Azevedo, R.; Guzi, T. J. Bioorg.
Med. Chem. Lett. 2013, 23, 6178; (i) Wurz, R. P.; Pettus,
L. H.; Jackson, C.; Wu, B.; Wang, H.; Herberich, B.;
Cee, V.; Lanman, B. A.; Reed, A. B.; Chavez, F., Jr.;
Nixey, T.; Laszlo, J., III; Wang, P.; Nguyen, Y.; Sastri,
C.; Guerrero, N.; Winston, J.; Lipford, J. R.; Lee, M. R.;
Andrews, K. L.; Mohr, C.; Xu, Y.; Zhou, Y.; Reid, D. L.;
Tasker, A. S. Bioorg. Med. Chem. Lett. 2015, 25, 847; (j)
Ishchenko, A.; Zhang, L.; Le Brazidec, J.; Fan, J.; Chong,
J. H.; Hingway, A.; Raditsis, A.; Singh, L.; Elenbaas, B.;
Hong, V. S.; Marcotte, D.; Silvian, L.; Enyedy, I.; Chao,
J. Bioorg. Med. Chem. Lett. 2015, 25, 474; (k) Wang, H.;
Cee, V. J.; Chavez, F.; Lanman, B. A.; Reed, A. B.; Wu,
B.; Guerrero, N.; Lipford, J. R.; Sastri, C.; Winston, J.;
Andrews, K. L.; Huang, Xin; L., Matthew R.; Mohr, C.;
Xu, Y.; Zhou, Y.; Tasker, A. S. Bioorg. Med. Chem. Lett.
2015, 25, 834; (l) Wu, B.; Wang, H.; Cee, V. J.; Lanman,
B. A.; Nixey, T.; Pettus, L.; Reed, A. B.; Wurz, R. P.;
Guerrero, N.; Sastri, C.; Winston, J.; Lipford, J. R.; Lee,
6. Wang, X.; Magnuson, S.; Pastor, R.; Fan, E.; Hu, H.;
Tsui, V.; Deng, W.; Murray, J.; Steffek, M.; Wallweber,
H.; Moffat, J.; Drummond, J.; Chan, G.; Harstad, E.;
Ebens, A. J. Bioorg. Med. Chem. Lett. 2013, 23, 3149.
7. (a) Woods, K. W.; Fischer, J. P.; Claiborne, A.; Li, T.;
Thomas, S. A.; Zhu, G. -D.; Diebold, R. B.; Liu, X.; Shi,
Y.; Klinghofer, V.; Han, E. K.; Guan, R.; Magnone, S.
R.; Johnson, E. F.; Bouska, J. J.; Olson, A. M.; de Jong,
R.; Oltersdorf, T.; Luo, Y.; Rosenberg, S. H.; Giranda, V.
L.; Li, Q. Bioorg. Med. Chem. 2006, 14, 6832; (b) Luo,
Y.; Shoemaker, A. R.; Liu, X.; Woods, K. W.; Thomas,
S. A.; de Jong, R.; Han, E. K.; Li, T.; Stoll, V. S.; Powlas,
J. A.; Oleksijew, A.; Mitten, M. J.; Shi, Y.; Guan, R.;
McGonigal, T. P.; Klinghofer, V.; Johnson, E. F.;
Leverson, J. D.; Bouska, J. J.; Mamo, M.; Smith, R. A.;
Gramling-Evans, E. E.; Zinker, B. A.; Mika, A. K.;
Nguyen, P. T.; Oltersdorf, T.; Rosenberg, S. H.; Li, Q.;
Giranda, V. L. Mol. Cancer Ther. 2005, 4, 977.
8. LE: Ligand efficiency = -1.4*log(Ki in molar)/(no. of
heavy atoms). Hopkins, A. L.; Groom, C. R.; Alex, A.
Drug Discovery Today 2004, 9, 430.
9. (a) Leeson P. D.; Springthorpe, B. Nature Rev. Drug
Discovery. 2007, 6, 881; (b) Shultz, M. D. Bioorg. Med.
Chem. Lett. 2013, 23, 5980.
10. Gerber, P. R.; Mfiller, K. J. Comput. Aided Mol. Des.
1995, 9, 251.
11. Synthesis of selected compounds 11, 12, and 14 is shown
in Scheme 1S in supplemental material.
12. Synthesis of 39 is shown in Scheme 2S in supplemental
material.

Graphical Abstract
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Discovery of 3,5-substituted 6-azaindazoles
as potent pan-Pim inhibitors
Huiyong Hu, Xiaojing Wang, Grace Ka Yan Chan, Jae H. Chang, Steven Do, Jake Drummond, Allen Ebens,
Wendy Lee, Justin Ly, Joseph Lyssikatos, Jeremy Murray, John G. Moffat, Qi Chao, Vickie Tsui, Heidi
Wallweber, Aleksandr Kolesnikov