Discovery and optimization of indoles and 7-azaindoles as Rho kinase (ROCK) inhibitors (part-I)

Article abstract of DOI:10.1016/j.bmcl.2011.09.083

Rho kinase (ROCK) inhibitors are potential therapeutic agents to treat disorders such as hypertension, multiple sclerosis, cancers, and glaucoma. Here, we disclose the synthesis, optimization, biological evaluation of potent indole and 7-azaindole based ROCK inhibitors that have high potency on ROCK (IC ₅₀ = 1 nM) with 740-fold selectivity over PKA (47). Moreover, 47 showed very good DMPK properties making it a good candidate for further development. Finally, docking studies with a homology model of ROCK-II were performed to rationalize the binding mode of these compounds and showed the compounds bound in both orientations to take advantage to H-bonds with Lys-121 of ROCK-II.

Full text of DOI:10.1016/j.bmcl.2011.09.083

Bioorganic & Medicinal Chemistry Letters 21 (2011) 7107–7112
Contents lists available at SciVerse ScienceDirect
Bioorganic & Medicinal Chemistry Letters
journal homepage: www.elsevier.com/locate/bmcl
Discovery and optimization of indoles and 7-azaindoles as Rho kinase
(ROCK) inhibitors (part-I)
Sarwat Chowdhury a, , E. Hampton Sessions a, , Jennifer R. Pocas a, Wayne Grant a, Thomas Schröter a,
Li Lin a, Claudia Ruiz a, Michael D. Cameron a, Stephan Schürer b, Philip LoGrasso a, Thomas D. Bannister a,
,
⇑
Yangbo Feng a,
⇑
a Translational Research Institute and Department of Molecular Therapeutics, The Scripps Research Institute, Scripps Florida, 130 Scripps Way, #2A1, Jupiter, FL 33458, USA
b Department of Pharmacology and Center for Computational Science, University of Miami, Miami, FL 33136, USA
a r t i c l e i n f o
a b s t r a c t
Article history:
Rho kinase (ROCK) inhibitors are potential therapeutic agents to treat disorders such as hypertension,
multiple sclerosis, cancers, and glaucoma. Here, we disclose the synthesis, optimization, biological eval-
uation of potent indole and 7-azaindole based ROCK inhibitors that have high potency on ROCK
(IC50 = 1 nM) with 740-fold selectivity over PKA (47). Moreover, 47 showed very good DMPK properties
making it a good candidate for further development. Finally, docking studies with a homology model of
ROCK-II were performed to rationalize the binding mode of these compounds and showed the com-
pounds bound in both orientations to take advantage to H-bonds with Lys-121 of ROCK-II.
Ó 2011 Elsevier Ltd. All rights reserved.
Received 16 August 2011
Accepted 20 September 2011
Available online 24 September 2011
Keywords:
Rho kinase
ROCK inhibitor
Indole
Azaindole
Protein kinase A
Pyrazole
Rho kinase (ROCK) is a serine/threonine kinase of significant
interest in drug discovery owing to its fundamental role in vital
signal transduction pathways central to many essential cellular
activities, including contraction, adhesion and migration. Once
activated by the GTP-bound G-protein Rho, ROCK phosphorylates
multiple substrates including myosin light chain (MLC), which ulti-
mately results in cellular contraction.1 The inhibition of the ROCK
pathway might provide a means of therapy for diseases such as
hypertension,2,3 glaucoma,4,5 multiple sclerosis,6 stroke,7 asthma,8
erectile dysfunction,9 central nervous system disorders,10 and tu-
mor metastasis,11 among other conditions. Most known ROCK
inhibitors are non-selective for the two isoforms (ROCK-I and
ROCK-II), which have approximately 92% sequence homology in
the kinase domain.12 The isoquinoline ROCK inhibitor fasudil, used
in Japan to treat cerebral vasospasm,13 is an ATP-competitive
inhibitor of modest potency, especially in cell-based assays.14 Re-
cently, several different families of ROCK inhibitors have been pub-
lished by our group15–21 along with IOP-lowering effects of two
series in glaucomatous rats.20,21 Herein, we discuss structure–
activity relationships of new ROCK inhibitors based on the indole
and azaindole scaffolds (Fig. 1).
In previous Letters, we have disclosed benzimidazole 118 and
benzothiazole 219 as potent ROCK inhibitors (Fig. 1). We wished
to expand our exploration to the corresponding indole and azain-
dole-based inhibitors shown in general structure 3. This new scaf-
fold would allow for substitution patterns not accessible in the
earlier ring systems, permitting chemoselective substitutions at
the N1, C2, and C3 ring positions of the indole/azaindole nucleus.
We expected that indoles with C3 amides might have especially
different properties from the benzothiazole 2-amides, since the
amide carbonyl would be positioned differently to interact with
the side chain amino group of Lys-121 in the ATP-binding site of
ROCK-II. Our previous work15–21 led us to believe that there may
be four potential interactions of scaffold 3 within the ATP binding
pocket that are relevant to ROCK potency and selectivity, shown in
Figure 1 for indole/azaindole scaffold 3. These include (1) Hydro-
gen bonds between the backbone NH of Met-172 in ROCK-II and
a nitrogen-containing H-bond acceptor in the inhibitor (R1). This
interaction may also be complemented by a second hydrogen bond
with the backbone carbonyl of Glu-170; (2) Hydrogen bond be-
tween an acceptor of the inhibitor to Lys-121, accomplished by
the benzimidazole N3 of inhibitor 1 and by the amide carbonyl
of benzothiazole 2; (3) Hydrophobic interactions between the gly-
cine-rich P-loop and an electron rich aromatic ring of the inhibitor,
accomplished by the chroman ring of benzimidazole 1 and the
⇑
Corresponding authors. Tel.: +1 561 228 2201 (Y.F.); tel.: +1 561 228 2206
(T.D.B.).
E-mail addresses: tbannist@scripps.edu (T.D. Bannister), yfeng@scripps.edu
(Y. Feng).
Contributed equally.
0960-894X/$ - see front matter Ó 2011 Elsevier Ltd. All rights reserved.
doi:10.1016/j.bmcl.2011.09.083

7108
S. Chowdhury et al. / Bioorg. Med. Chem. Lett. 21 (2011) 7107–7112
O
O
N
N
N
S
N
H
N
HN
N
N
OMe
OMe
N
NH2
2
1
ROCK-II IC50 < 1 nM
ROCK-I IC50 = 4 nM
PKA IC50 = 45 nM
ROCK-II IC50 = 2 nM
ROCK-I IC50 = 22 nM
PKA IC50 = 485 nM
ppMLC (cell) IC50 = 6 nM
ppMLC (cell) IC50 = 85 nM
Lys-121
P-loop
R4
O
3
N
X
2
6
R3
1
N
Y
Met-172
R1
and Glu-170
kinase hinge
R2
Asp-176
X,Y = CH, N
3
Figure 1. Benzimidazole and benzothiazole ROCK inhibitors 1–2 and proposed interactions of indole/azaindole 3 within the ATP binding pocket of ROCK-II.
methoxybenzyl group of benzothiazole 2; and (4) Polar interac-
tions between the inhibitor and Asp-176 in ROCK-II, accomplished
by the N-2-dimethylaminoethyl group of benzothiazole inhibitor 2.
The first three of these interactions can confer high ROCK affinity.
The fourth interaction, accessed by indole/azaindole inhibitors
through a side chain (R2 or R3 in structure 3) will also perturb many
pharmaceutical properties of these ROCK inhibitors such as po-
tency, selectivity, cell permeation, brain penetration, aqueous sol-
ubility, and in vitro and in vivo pharmacokinetic properties.
Since the indole scaffold 3 lacks the nitrogen atom in benzimid-
azole 1, which is responsible for a key interaction (with Lys-121 in
ROCK-II), we believed that a C2 or C3 carbonyl group would be
essential for this scaffold to obtain high ROCK affinity. Given that
indole 2-carboxamides would possibly be isosteric with benzothi-
azole 2-carboxamides such as inhibitor 2, we designed an expedi-
tious synthesis of indole 8, as shown in Scheme 1. Briefly, the
sequence began with the commercially available acid 4. HATU-
mediated amide coupling and a Suzuki heteroarylation reaction al-
lowed for the assembly of indole 8, which was a potent ROCK
inhibitor with good inhibitory activity in both enzyme assays and
cell-based myosin light chain bis-phosphorylation assays
(ppMLC)22 (ROCK-II IC50 = 2 nM, ppMLC IC50 = 28 nM).23 Especially
noteworthy was the much reduced activity against protein kinase
A (PKA, IC50 = 6700 nM, >3000-fold selectivity), a closely homolo-
gous kinase chosen to indicate the selectivity potential against
other members of the human kinome,24 compared to the benz-
imidazole and benzothiazole based ROCK inhibitors 1 and 2.
In parallel, we pursued the synthesis of an analogous indole 3-
carboxamide 12. Placing the amide carbonyl group at the indole C3
position was not as established in our ROCK inhibitor studies. As
shown in Scheme 2, acylation and hydrolysis of 6-bromoindole 9
gave acid 11, which was then converted into pyrazole 12 by the
same two-step sequence used in the synthesis of indole 2-carbox-
amide ROCK inhibitor 8. Remarkably, the unsubstituted indole 3-
carboxamide 12 was also an extremely potent ROCK inhibitor in
both biochemical and cell-based assays (ROCK-II IC50 <1 nM,
ppMLC IC50 = 4 nM).
Having established that both indole 2- and 3-carboxamides are
suitable starting points for ROCK inhibitor design, we then targeted
the synthesis and evaluation of their azaindole analogs. It was ex-
pected that an additional basic nitrogen atom present in the scaf-
fold would enhance aqueous solubility and perhaps confer more
favorable drug properties. The prototype 5-azaindole 2-carboxam-
ide analog was prepared based on the route of Scheme 3. It began
with the iodination of commercially available amine 13. Heating
iodide 14 with pyruvic acid, DABCO and Pd(OAc)2 gave the cycliza-
tion25 product 5-azaindole-2-carboxylic acid 15.25 HATU amide
coupling followed by a Suzuki heteroarylation yielded the desired
amide 16. Surprisingly, compound 16 was only a modestly potent
ROCK inhibitor (ROCK-II IC50 = 190 nM).
The effect of an added nitrogen atom in the scaffold was further
investigated, however, with the 7-azaindole regioisomer, which
was accessed as shown in Scheme 4. Pivaloylation of amine 17, fol-
lowed by directed halogenation,26 and acidic pivaloyl group re-
H2N
O
O
OMe
5
N
H
HN
Br
N
H
OH
Br
HATU, Et3N, rt
DMF
6
OMe
4
O
O
N
HN
B
7
O
N
HN
N
HN
H
OMe
PdCl2(PPh3)2, Na2CO3,
Dioxane/H2O, 100 °C
8
Scheme 1. Synthesis of indole 2-carboxamide ROCK inhibitor 8.

S. Chowdhury et al. / Bioorg. Med. Chem. Lett. 21 (2011) 7107–7112
7109
O
CO2H
CF3
TFAA
NaOH
N
H
Br
THF/H2O
N
Br
N
H
Br
H
9
10
11
H
N
O
1) 5, HATU, Et3N, DMF, rt
OMe
N
2) 7, PdCl2(PPh3)2, Na2CO3,
N
HN
H
12
Dioxane/H2O, 100 °C,
Scheme 2. Synthesis of indole 3-carboxamide ROCK inhibitor 12.
I
N
N
pyruvic acid, DMF,
N
AgSO4, I2, EtOH
rt, 72 h
Cl
Cl
NH2
Cl
NH2
DABCO, Pd(OAc)2,
110 °C
13
15
14
HN
N
1) 5, HATU, Et3N, DMF
N
H
O
CO2H
N
HN
N
H
2) 7, Pd(PPh3)4, K2CO3,
EtOH/toluene, 145 °C
O
16
Scheme 3. Synthesis of 5-azaindole 2-carboxamide ROCK inhibitor 16.
I
1)PivCl, TEA,
CH2Cl2, rt, 3 h
O
HCl, dioxane
reflux,14 h
Cl
N
NH2
Cl
N
N
H
2) t-BuLi, -78 °C,
2 h, then I2, 16 h
17
18
I
O
pyruvic acid, DMF, DABCO,
Pd(OAc)2, 110 °C
N
H
OH
Cl
N
Cl
N
NH2
19
20
O
1) 5, HATU, Et3N, DMF
OMe
N
N
N
H
2) 7, Pd(PPh3)4,K2CO3,
EtOH/toluene, 145 °C,
HN
HN
21
Scheme 4. Synthesis of 7-azaindole 2-carboxamide ROCK inhibitor 21.
moval gave iodide 19. Cyclization gave the key azaindole carbox-
ylic acid 20. The two-step coupling and Suzuki process under
conditions analogous to those in Scheme 3 gave the desired 7-aza-
indole 2-carboxamide 21. In contrast to the 5-azaindole analog 16,
this 7-azaindole 2-carboxamide, like its indole analog 8, was found
to be a potent ROCK inhibitor (ROCK-II IC50 = 2 nM), suggesting
that further optimization efforts in the 7-azaindole scaffold were
also warranted.
Given the encouraging result with 7-azaindole-2-carboxamide
inhibitor 21, we then sought its analogous 3-carboxamide regio-
isomer. The synthesis (Scheme 5) began with oxidation of com-
mercially available 7-azaindole (22) to the corresponding N-
oxide.27 A known two-step procedure (chlorination plus acylation,
then hydrolysis)28 gave 6-chloro-7-azaindole 23. Carboxylation,
HATU-mediated amine coupling, and a Suzuki heteroarylation then
gave the desired 7-azaindole 3-carboxamide 25, which likes its in-
dole analog 12 was found to be a potent ROCK inhibitor (ROCK-II
IC50 = 2 nM) with excellent selectivity against PKA (IC50 = 8100 nM,
>4000-fold).
The C6 pyrazole group of these inhibitors is anticipated to en-
gage in key hydrogen bonding interactions to the kinase hinge
(Fig. 1), and is essential for activity in several ROCK inhibitors.19
Analogs with other heteroaryl groups were prepared to explore
the tolerance of other hinge-binding moieties (Table 1). These
compounds were accessed by coupling appropriate indole/azain-
dole 2-carboxylic acid with m-methoxy benzyl amine followed
by heteroarylation under Suzuki conditions. The most potent 2-
carboxamide indole has a pyrazole as the hinge-binding group.
While aminopyrimidine 27 also had good affinity for ROCK, pyri-
dine 26 and aminopyridine 28 were less potent inhibitors. 7-Azain-
doles were found to bind to ROCK with high affinity and they
resembled their indole analogs in preferring pyrazole-type groups
(21, 31, and 32). However, the PKA selectivity was much reduced
(21 vs 8). In comparison, 5-azaindoles (16, 29, and 30) exhibited

7110
S. Chowdhury et al. / Bioorg. Med. Chem. Lett. 21 (2011) 7107–7112
1) TFAA, 0 °C, 1 h;
1) m-CPBA, Et2O, 0 °C, 5 min then rt, 2 h
then rt 14 h
N
H
N
H
2) HMDS, THF, ClCOOEt, rt, 4 h
3) MeOH, 4M NaOH, rt, 6 h
N
Cl
N
23
2) 2M NaOH, 80 °C,
22
10h
COOH
O
N
HN
1) 5, HATU, Et3N, DMF
OMe
N
H
N
N
Cl
N
2) 7, Pd(PPh3)4, K2CO3,
EtOH/toluene, 145 °C, 1 h
N
H
H
24
25
Scheme 5. Synthesis of 7-azaindole 3-carboxamide ROCK inhibitor 25.
Table 1
weak activity in this study and hence, their SAR was not studied
further.
Exploration of the C6 hinge-binding group of indole, 5-azaindole, and 7-azaindole 2-
carboxamide scaffolds
A similar SAR study with indole- and 7-azaindole-3-carboxam-
ides (Table 2) also revealed that pyrazole is the most effective
hinge binding group. Interestingly, several incongruities between
the two series also became apparent. First, in contrast to the 2-car-
boxamides, the pyridine group was well tolerated in both indole
and 7-azaindole3-carboxamide series (33–34). Second, 7-azaindole
3-carboxamides (25, 34) showed an enhanced PKA selectivity as
compared to both the 7-azaindole 2-carboxamide (21 and 32 in
Table 1) and the indole 3-carboxamide (12, 33) counterparts.
In the design of inhibitors 8, 12, 21, 25 and their analogs shown
in Tables 1 and 2, we relied upon our previous studies of other scaf-
folds19 to choose a meta-methoxy benzyl group to interact with the
glycine rich P-loop region of the ATP binding pocket. In order to ex-
plore the tolerance of ROCK for indoles and 7-azaindoles with
other amide groups, commercially available amines were used in
the penultimate step to access diverse amides of indole-3-carbox-
ylic acids and 7-azaindole-2-carboxylic acids followed by a Suzuki
coupling for installation of the hinge binding group. It was espe-
cially of interest to vary the amide groups in the 3-carboxamides,
since the C3 regiochemistry could alter the established preferences
seen with benzothiazole 2-carboxamides (such as inhibitor 2).19 As
shown in Table 3, affinity for ROCK was the highest for indole 12,
which contains a m-methoxy benzyl group. Less inhibition was ob-
served for methoxy regioisomers 35 and 36, and for fluorinated
analogs 37 and 38 (compounds 35 and 38 still gave high ROCK po-
tency, though). An (R)-benzylic methyl group (compound 39) was
superior to the (S)-benzylic methyl group (40), and nonaromatic
and arylethyl moieties (41–43) were less optimal. It is also inter-
esting to note that a 2,5-dimethoxy substituted benzyl amide
was not tolerated (44) although the individual methoxy substitu-
tion at each position gave potent ROCK inhibitors (compounds 12
and 35). In light of these results, we preferred the mono m-meth-
oxy benzyl substituent in all further studies involving inhibitors
belonging to the indole and azaindole scaffolds. This trend in favor
of a meta-methoxy group and the (R)-benzylic methyl substituent
is also present in 7-azaindole 2-carboxamides (Table 3, compounds
21, 45–48). However, PKA selectivity was slightly reduced in the 7-
azaindole series.
O
7
NH
X
NH
Het
O
Y
a
Compd
X
Y
Het
IC50 (nM)
ROCK-I
ROCK-II
2
PKA
8
CH
CH
19
6700
HN
N
26
27
28
CH
CH
CH
CH
CH
CH
160
36
1900
480
>20000
11000
N
H2N
N
N
N
H2N
1200
2100
>20000
16
29
CH
CH
N
N
190
530
870
9400
HN
N
HN
1200
>20000
N
Me
30
21
CH
N
N
420
2
1100
12
>20000
140
N
CH
HN
N
N
HN
31
32
N
N
CH
CH
5
19
230
Me
220
720
17000
N
The excellent potency shown in both the 2-carboxamides and
3-carboxamidesof the indole as well as the 7-azaindole series is
somewhat surprising considering the key interactions proposed
are the hydrogen bonds in the hinge binding area and the interac-
tion between the amide carbonyl group and the side chain amino
group of residue Lys-121 in ROCK-II. To understand these observa-
tions, we used previously described methods29 to perform docking
studies of several indole and azaindole inhibitors in a ROCK-II
homology model. These studies led us to propose that two dis-
tinctly different flipped orientations of the indole nucleus, as
shown in Figure 2, are important to consider. In indole 2-carbox-
amides such as azaindole 21 (compound shown in green in
a
Average of two or more measurements with standard derivations 630%.
Fig. 2), the indole NH is projected away from Asp-176 of ROCK-II.
In the other orientation (as in azaindole 25 shown in pink), pre-
dominant for most if not all 3-carboxamides, the indole NH is in-
stead projected towards Asp-176. Importantly, both orientations
enable H-bonding interactions between the Lys-121 side chain
amino group of the protein and the indole carbonyl oxygen as well
as interactions with the hinge binding group and the P-loop recog-
nition elements, lowering the overall energy of binding.

S. Chowdhury et al. / Bioorg. Med. Chem. Lett. 21 (2011) 7107–7112
7111
Table 2
Table 3
Exploration of the C6 hinge-binding group in the indole- and 7-azaindole-3
carboxamide scaffolds
Exploration of the benzyl amide group in the indole and 7-azaindole-2 carboxamide
scaffold
O
H
N
O
NH
HN
O
R
R
N
H
N
Het
HN
X
NH
O
N
HN
H
N
a
Compd
X
Het
IC50 (nM)
ROCK-I
B
A
N
ROCK-II
<1
PKA
510
a
Compd
R
Structure
IC50 (nM)
ROCK-II ROCK-I PKA
12
33
25
34
CH
CH
N
<1
11
11
48
HN
OMe
N
12
35
36
37
A
A
A
A
<1
<1
510
2
2
7
730
N
9
23
970
MeO
8100
10000
HN
N
750
220
1900
760
>20000
4000
OMe
OCF3
F
N
N
a
Average of two or more measurements with standard derivations 630%.
38
39
A
A
8
34
2
360
930
F
The ability of the nitrogens in the pyrazole hinge-binding group
to serve as a hydrogen bond acceptor/donor group, interacting with
Met-172 and Glu-170 through tautomerization or transposition via
single bond rotation, is possibly another key factor giving rise to high
potency in both regioisomeric series. Additionally, this hypothesis
also can be used to address the weak ROCK affinity of the 2-carbox-
amides containing a 4-pyridyl group at C6, a hinge-binding group
lacking an NH donor and in which the location of the H-bond accept-
ing atom is fixed. This binding motif is consistent with all SAR results
observed in our indole and azaindole series, especially when the in-
dole NH or the amide NH is substituted (see part-II).
The in vitro and in vivo pharmacokinetic properties were also
used to evaluate these novel ROCK inhibitors. The most important
observations from the in vitro data (Table 4) are that the human
microsomal stability is greatly reduced by moving the carboxam-
ide from the C2 to C3 position (8 vs 12, 21 vs 25), and that the
7-azaindole scaffold is much cleaner than the indole scaffold in
terms of CYP-450 enzyme inhibitions (21/47 vs 8, 25 vs 12).
Replacement of the pyrazole by an aminopyrimidine group signif-
icantly lowered the CYPs inhibitions but it also reduced the micro-
somal stability (27 vs 8). On the other hand, replacement of the
OMe
<1
OMe
40
A
130
500
16000
41
42
43
A
A
A
76
170
3
170
240
18
2800
1900
500
OMe
S
OMe
OMe
44
A
740
1340
13100
MeO
MeO
21
45
46
B
B
B
2
12
140
pyrazole by
a pyridine moiety slightly increased the CYPs
5
130
500
150
inhibitions and decreased the microsomal stability (33 vs 12).
Interestingly, the 3A4 enzyme inhibition is much lower in the 2-
methoxy benzyl amide (35) than in the 3-methoxy benzyl amide
(12). It is also important to note that a methyl substitution at the
benzylic position helped to reduce CYPs inhibitions (39 vs 12) in
the indole 3-carboxamide scaffold while a similar substitution in
the 7-azaindole 3-carboxamide scaffold did not change much the
microsomal stability and the CYPs inhibitions (47 vs 21).
The in vivo pharmacokinetic data shown in Table 5 demon-
strated that all these selected indole and 7-azaindole based ROCK
inhibitors had low clearance (Cl), low volume of distribution
(Vss), and high AUC in iv dosing. However, only compounds 8, 21,
and 47 exhibited a good half-life (t1/2), a fair oral bioavailability
(%F), and a high Cmax and AUC in oral (po) dosing. These in vivo
pharmacological data correlated well with the corresponding
microsomal stability: high microsomal stability generally gave
high oral absorbance.
180
>20000
OMe
OMe
47
48
B
B
1
6
740
OMe
290
560
11000
a
Average of two or more measurements with standard derivations 630%.
ity against the Rho kinase. These compounds possess high ROCK-II
potency and moderate to excellent PKA selectivity. The overall best
compounds for oral dosing, considering target activity, selectivity,
CYP 450 inhibitions, and pharmacokinetic properties, are the 7-
azaindole 2-carboxamides 21 (also coded as SR7355) and 47 (also
In conclusion, we have synthesized a series of 2- and 3-carbox-
amide indoles and azaindoles and evaluated their biological activ-

7112
S. Chowdhury et al. / Bioorg. Med. Chem. Lett. 21 (2011) 7107–7112
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Figure 2. Proposed two alternate binding modes of 7-azaindole 2- and 3-carbox-
amides (compound 21 and 25, respectively).
13. Shibuya, M.; Suzuki, Y.; Sugita, K.; Saito, I.; Sasaki, T.; Takakura, K.; Nagata, I.;
Kikuchi, H.; Takemae, T.; Hidaka, H., et al J. Neurosurg. 1992, 76, 571.
14. Hydroxyfasudil, the active metabolite of fasudil, is generally effective in cell-
Table 4
In vitro DMPK properties for selected compounds
based assays at or above 1 lM; se:e Nakamura, K.; Nishimura, J.; Hirano, K.;
Compd
t1/2 (min)
CYP-450 Enzyme inhibition at 10 lM (%)
Ibayashi, S.; Fujishima, M.; Kanaide, H. J. Cereb. Blood Flow Metab. 2001, 21, 876.
15. Feng, Y.; Cameron, M.; Frackowiak, B.; Griffin, E.; Lin, L.; Ruiz, C.; Schröter, T.;
LoGrasso, P. Bioorg. Med. Chem. Lett. 2007, 17, 2355.
16. Chen, Y. T.; Bannister, T.; Weiser, A.; Griffin, E.; Lin, L.; Ruiz, C.; Cameron, M.;
Schürer, S.; Duckett, D.; Schröter, T.; LoGrasso, P.; Feng, Y. Bioorg. Med. Chem.
Lett. 2008, 18, 6406.
17. Sessions, E. H.; Yin, Y.; Bannister, T. B.; Weiser, A.; Griffin, E.; Pocas, J.; Cameron,
M.; Ruiz, C.; Lin, L.; Schürer, S.; Schröter, T.; LoGrasso, P.; Feng, Y. Bioorg. Med.
Chem. Lett. 2008, 18, 6390.
18. Sessions, E. H.; Smolinksi, M.; Wang, B.; Frackowiak, B.; Chowdhury, S.; Yin, Y.;
Chen, Y. T.; Ruiz, C.; Lin, L.; Pocas, J.; Schröter, T.; Cameron, M.; LoGrasso, P.;
Feng, Y.; Bannister, T. Bioorg. Med. Chem. Lett. 2010, 20, 1939.
19. Yin, Y.; Lin, L.; Ruiz, C.; Cameron, M.; Pocas, J.; Grant, W.; Schröter, T.; Chen, W.;
Duckett, D.; Schürer, S.; LoGrasso, P.; Feng, Y. Bioorg. Med. Chem. Lett. 2009, 19,
6686.
HLM
1A2
2C9
2D6
3A4
8
80
25
53
15
17
10
21
24
59
42
87
4
87
97
38
86
14
99
91
90
60
81
51
32
12
8
75
34
33
41
87
72
22
46
14
80
37
56
23
12
21
25
27
33
35
39
47
5
12
67
89
39
13
20. Fang, X.; Yin, Y.; Chen, Y. T.; Yao, L.; Wang, B.; Cameron, M. D.; Lin, L.; Khan, S.;
Ruiz, C.; Schröter, T.; Grant, W.; Weiser, A.; Pocas, J.; Pachori, A.; Schürer, S.; Lo
Grasso, P.; Feng, Y. J. Med. Chem. 2010, 53, 5727.
21. Yin, Y.; Cameron, M. D.; Lin, L.; Khan, S.; Schröter, T.; Grant, W.; Pocas, J.; Chen,
Y. T.; Schürer, S.; Pachori, A.; LoGrasso, P.; Feng, Y. ACS Med. Chem. Lett. 2010, 1,
175.
22. (a) Schröter, T.; Minond, D.; Weiser, A.; Dao, C.; Habel, J.; Spicer, T.; Chase, P.;
Baillargeon, P.; Scampavia, L.; Schürer, S. C.; Chung, C.; Mader, C.; Southern, M.;
Tsinoremas, N.; LoGrasso, P.; Hodder, P. J. Biomol. Screen. 2008, 13, 17; (b)
Schröter, T.; Griffin, E.; Weiser, A.; Feng, Y.; LoGrasso, P. Biochem. Biophys. Res.
Commun. 2008, 374, 356.
Table 5
In vivo (rat) pharmacokinetic dataa for selected inhibitors
Cmpd Cl (mL/
min/kg)
Vss
(L/
kg)
t1/2
(h)
AUC iv
M h)
AUC po
M h)
Cmax po
M)
Oral F
(%)
(
l
(
l
(l
8
3.2
4.9
2.1
7.6
5.8
6.6
0.46
0.26
0.27
0.52
0.37
0.94
2.0
1.1
2.0
1.0
1.1
2.0
15.3
10.0
22.4
6.4
8.1
7.6
8.7
1.0
14.4
0.3
1.4
5.0
1.5
0.5
1.8
0.1
0.3
0.6
28
5
32
3
9
33
12
21
25
39
47
23. For benzothiazoles (e.g., inhibitor
2 in Fig. 1) the amide substituent is
important for cell-based activity and added ROCK-II potency. The
benzothiazole analog of indole 8 has the following binding profile: ROCK-II
IC50 = 18 nM, ROCK-I IC50 = 76 nM, PKA IC50 = 5300 nM, ppMLC IC50 = 2700 nM.
24. In many instances the compounds reported herein were also evaluated versus
a
Data were the average from three determinations with standard derivations
a selected panel of other kinases (e.g., JNK3). No off-target activity <5 lM was
seen. Development compounds will be profiled versus an extended panel of
>300 kinases.
630%. Dosed at 1.0 mg/kg (iv) or 2.0 mg/kg (po).
25. Fyfe, M. C. T.; Thomas, G. H.; Gardner, L. S.; Bradley, S. E.; Gattrell, W.;
Rasamison, C. M.; Shah, V. K. WO 2006067532, 2006.
coded as SR8363). Further SAR studies for indole and 7-azaindole
based ROCK compounds bearing substitutions on the indole NH
and/or the amide NH positions, or the indole C3 position are ad-
dressed in the following Letter (part-II).
26. Krulle, T. M.; Rowley, R. J.; Thomas, G. H. WO 2006059164, 2006.
27. Berdini, V.; Boyle, R.G.; Saxty, G.; Walker, D. W.; Woodhead, S. J.; Wyatt, P. G.;
Caldwell, J.; Collins, I.; Da Fonseca, T. F. WO 2006046024, 2006.
28. Minakata, S.; Komatsu, M.; Ohshiro, Y. Synthesis 1992, 7, 661.
29. Feng, Y.; Yin, Y.; Weiser, A.; Griffin, E.; Cameron, M. D.; Lin, L.; Ruiz, C.; Schürer,
S. C.; Inoue, T.; Rao, P. V.; Schröter, T.; LoGrasso, P. J. Med. Chem. 2008, 51, 6642.
Acknowledgments
We thank Professor William Roush and Professor Patrick Griffin
for their support, and Dr. Yen Ting Chen for helping the preparation
of this manuscript.