Benzothiazoles as Rho-associated kinase (ROCK-II) inhibitors

Article abstract of DOI:10.1016/j.bmcl.2009.09.115

A series of benzothiazole derivatives as ROCK inhibitors have been discovered. Compounds with good biochemical and cellular potency, and sufficient kinase selectivity have been identified.

Full text of DOI:10.1016/j.bmcl.2009.09.115

Bioorganic & Medicinal Chemistry Letters 19 (2009) 6686–6690
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Bioorganic & Medicinal Chemistry Letters
journal homepage: www.elsevier.com/locate/bmcl
Benzothiazoles as Rho-associated kinase (ROCK-II) inhibitors
Yan Yin a, Li Lin a, Claudia Ruiz a, Michael D. Cameron a, Jennifer Pocas a, Wayne Grant a, Thomas Schröter a,
Weimin Chen a, Derek Duckett a, Stephan Schürer b, Philip LoGrasso a, Yangbo Feng a,
*
a Translational Research Institute and Department of Molecular Therapeutics, The Scripps Research Institute, Florida, 130 Scripps Way, #2A1, Jupiter, FL 33458, United States
b Department of Pharmacology and Center for Computational Science, University of Miami, Miami, FL 33136, United States
a r t i c l e i n f o
a b s t r a c t
Article history:
A series of benzothiazole derivatives as ROCK inhibitors have been discovered. Compounds with good
biochemical and cellular potency, and sufficient kinase selectivity have been identified.
Ó 2009 Elsevier Ltd. All rights reserved.
Received 28 August 2009
Revised 28 September 2009
Accepted 30 September 2009
Available online 3 October 2009
Keywords:
ROCK
Rho
Benzothiazole
Chroman
Pyrazole
Glaucoma
Rho-associated kinases (ROCK) is a serine/threonine protein ki-
nase from the AGC kinase family with two isoforms identified as
pound had a moderate selectivity against PKA (IC50 = 156 nM, ꢀ17-
fold) and a low cellular potency (IC50 = 1500 nM) as assessed by
myosin light chain bis-phosphorylation (ppMLC) assays.13 Using
6a as the lead compound, a series of SAR studies were performed
to improve the pharmaceutical properties of benzothiazole based
ROCK inhibitors.
ROCK-I (or ROCKb) and ROCK-II (or ROCK ).1 Upon activation by
a
GTP-bound RhoA, ROCK phosphorylates many substrates such as
myosin light chain (MLC) and controls a variety of cellular func-
tions, including smooth muscle contraction, proliferation, stress-fi-
ber formation, cell migration, cell adhesion, and gene expression.2
Inhibition of the Rho/ROCK pathway has proven to be a promising
strategy for several indications such as glaucoma,3 asthma,4 multi-
ple sclerosis,5 stroke,6 cancer,7 erectile dysfunction,8 and
hypertension.2b,9
Small molecule ROCK inhibitors have been reported by several
groups.10 Recently, our group also disclosed ROCK-II inhibitors
from multiple structural classes (Fig. 1).11 These include piperazine
and aminopiperidine substituted indazoles (1 and 2),11a,e benzodi-
oxan- and chroman-based amides (3),11b,c and benzimidazole and
benzoxazole based compounds (4 and 5).11d,e Here, we report a
new class of ROCK inhibitors. This class was based on a benzothi-
azole scaffold and was analogous to benzimidazole 4 and benzox-
azole 5. The benzothiazole ring is larger than the benzoxazole and
benzimidazole rings and is expected to give different properties.
Thus, the benzothiazole-chromane derivative 6a was identified as
a potent ROCK-II inhibitor (IC50 = 9 nM) with good stability in liver
microsomes (t1/2 = 47 min in human, 23 min in rat), and low inhi-
bition against human CYP isoforms.12 On the other hand, this com-
The SAR of various nitrogen-containing five- or six-membered
heterocycles as the hinge-binding moieties was first investigated
(Table 1). Replacement of the aminopyrimidine by a pyridine
(6b) slightly reduced ROCK-II potency while maintaining PKA
selectivity (ꢀ25-fold). Substitution on the pyridine moiety (6c) fur-
ther reduced the compound activity. Notably, application of a pyr-
azole group as the hinge-binding moiety led to compound 6d
which had similar ROCK inhibitory potency to 6a in both enzyme
and cell-based ppMLC assays, but with improved selectivity
against PKA (30-fold). On the other hand, methyl substitution on
the pyrazole ring (6e) reduced both the potency and the selectivity
over PKA. It is interesting to compare these results to what we ob-
served for the benzimidazole/benzoxazole series, where a 2-ami-
nopyrimidine as the hinge-binding moiety was the optimal in
terms of ROCK-II potency and selectivity against PKA.11d Therefore,
the unsubstituted pyrazole moiety was used in all subsequent
optimizations.
The effect of substitutions on the benzothiazole ring was stud-
ied (Table 2). Fluoro-substitution on the 5-position (6f) reduced
both the potency (IC50 = 47 nM compared to 11 nM in 6d) and
the selectivity against PKA (11-fold compared to 30-fold in 6d).
However, fluoro-substitution on the 4-position led to compound
* Corresponding author.
E-mail address: yfeng@scripps.edu (Y. Feng).
0960-894X/$ - see front matter Ó 2009 Elsevier Ltd. All rights reserved.
doi:10.1016/j.bmcl.2009.09.115

Y. Yin et al. / Bioorg. Med. Chem. Lett. 19 (2009) 6686–6690
6687
Figure 1. ROCK-II inhibitors.
6g which had similar potency against ROCK-II as compounds 6a
and 6d and improved selectivity over PKA (43-fold). Introduction
of a methoxy group on the 4-position (6h) significantly increased
the PKA selectivity (P160-fold) although the ROCK-II inhibition
was reduced slightly. Encouraged by the results of compound 6h,
other larger substitutions on this position were investigated. The
2-morpholinoethoxy and the 2-tetrahydrofuranylethoxy moieties
(6i and 6j, respectively) were not tolerated, probably due to the
large rings in these two groups. On the other hand, the 2-dimeth-
ylaminoethyl substitutions (6k and 6l) produced effective ROCK-II
inhibitors.14 Moreover, the alkoxy compound 6k had good selectiv-
ity against PKA (P75-fold), while the tertiary amine linked com-
pound 6l had diminished selectivity (ꢀ12-fold). It is noteworthy
that both 6k and 6l demonstrated better cell activities compared
to 6d.
Table 1
SAR of hinge-binding moieties
Compd
Ar
ROCK-IIa
(nM)
PKAa
(nM)
ppMLCa
(nM)
6a
6b
6c
6d
6e
2-Aminopyrimidine-4-yl
Pyridin-4-yl
2-Methylpyridin-4-yl
1H-Pyrazol-4-yl
9
42
1200
11
156
1097
7993
341
1500
ndb
ndb
1550
3-Methyl-1H-pyrazol-4-yl
25
404
ndb
a
IC50 values are means of two or more experiments with standard deviation
630%.
b
Not determined.
SAR on the chroman ring was investigated to obtain more selec-
tive compounds which also had high cell potency (Table 3). Map-
ping different positions of the chroman ring with a methoxy
group in closely related series11b demonstrated that a substitution
at the 6-position (6m) provided the best compound. Thus, small
functional groups such as electron-donating groups (6m and 6n)
and electron-withdrawing groups (6o, 6p, and 6q) were applied
at the 6-position. These compounds showed slightly reduced
ROCK-II potency but improved selectivity against PKA with the
exception of 6o. The best compounds came from 6-carboxamide
substitutions containing a tertiary amine (6r, 6s). These com-
pounds had high ROCK-II potency (sub-nanomolar or single-digital
nanomolar), high selectivity against PKA (83-fold and 847-fold for
Table 2
SAR of 6 on the benzothiazole ring
ID
Ra
ROCK-IIb (nM)
PKAb (nM)
ppMLCb (nM)
6f
6g
6h
5-Fc
F
OCH3
47
14
32
537
644
>5000
>2700
>2700
1241
Table 3
SAR of 6 on the chroman ring
6i
6j
6k
6l
314
500
66
>5000
>5000
>5000
702
ndd
ndd
365
365
ID
R
ROCK-IIa
(nM)
PKAa
(nM)
ppMLCa
(nM)
6m
6n
6o
6p
6q
6r
OCH3
CH3
Cl
F
COOCH3
CONH(CH2)2N(CH3)2
CONH(CH2)3N(CH3)2
45
93
75
38
59
7
>20,000
>20,000
1775
1929
>5000
582
>2700
ndb
ndb
51
1485
1485
20
a
Substitution at 4-position.
IC50 values are means of two or more experiments with standard deviation
630%.
6s SR6074
0.9
765
<4
b
a
IC50 values are means of two or more experiments with standard deviation
650%.
c
Substitution at 5-position.
Not determined.
d
b
Not determined.

6688
Y. Yin et al. / Bioorg. Med. Chem. Lett. 19 (2009) 6686–6690
6r and 6s, respectively), and excellent cell potency. The high cell
activity obtained was probably due to the high aqueous solubility
of 6r and 6s, in addition to their high potency against ROCK-II.
Compounds 6r and 6s also exhibited favorable human microsomal
stability with a half-life of 35 min and 34 min, respectively.
The next step in our optimizations of benzothiazole based ROCK
inhibitors was to replace the chroman moiety with achiral groups.
After screening several classes of substitutions at this position,
benzyl carboxamides were discovered to give potent and selective
ROCK-II inhibitors. As shown in Table 4, secondary benzyl amides
19a–c showed good ROCK-II activity and selectivity over PKA.
Among these three, compound 19b was the best with an IC50 value
of 18 nM for ROCK-II and 300-fold selectivity over PKA. Alkylation
of the amide NH was applied to increase the cell potency and aque-
ous solubility. Thus, simple alkyl groups such as methyl (19d),
ethyl (19e), and cyclopropyl (19f) were evaluated. Although
ROCK-II inhibition decreased slightly, the cell potency was signifi-
cantly improved due to the substitution by these alkyl groups. Sub-
stitution of the amide NH of 19b with groups possessing
heteroatoms gave even better inhibitors. Compound 19g, with a
methoxyethyl group, showed good inhibition of ROCK-II, and
2000-fold selectivity over PKA. The dimethylaminoethyl com-
pound (19h, SR6494) showed excellent inhibitions in both enzyme
and cellular assays (IC50 values of 0.4 nM and <6 nM, respectively)
and good selectivity over PKA (>100-fold). Compound 19h had also
reasonable human microsomal stability (t1/2 = 15 min). The phar-
macokinetic properties of 19h in rats (Cl = 50 ml/min/kg, F = 0%)15
indicated that this compound would have minimum systemic
exposure, possibly making it a good candidate for topical applica-
tion such as in a glaucoma therapy.
To assess the selectivity of the benzothiazole based inhibitors
against other kinases, compounds 6s, 19e, and 19h were chosen
for counter screening over several related or undesirable kinase
Table 4
SAR of benzothiazole-2-carboxamides 19
targets such as MRCKa, JNK3, and p38 (p38 and PKA are undesir-
able targets).11b–d The results shown in Table 5 demonstrated that
these compounds were quite selective except for 19h which is a
potent inhibitor of PKA. Screening against ROCK-I indicated that
these benzothiazole compounds are pan-ROCK inhibitors. In the
future, broader kinase counterscreening will be done on the key
compounds that will be advanced to determine specificity beyond
the limited number of kinases tested here.
ID
R1
R2
ROCK-IIa PKAa
ppMLCa
(nM)
(nM)
(nM)
The synthesis of various 2-chromanylbenzothiazoles 6 is out-
lined in Scheme 1. A SN2 reaction of 4-bromo-2-fluoro-1-nitroben-
zene (7) with (4-methoxyphenyl)-methane-thiol gave thiol 8. In
the presence of 5 equiv of tin(II) chloride dihydrate, nitrobenzene
8 was reduced to aniline 9. Amide coupling reactions went
smoothly by treating 9 with chroman-3-carbonyl chlorides (pre-
pared by treating the corresponding acids with thionyl chloride
in CH2Cl2) to produce 10. Bromide 11 was then obtained through
one pot, microwave-assisted deprotection and cyclization reac-
tions. Finally, Suzuki coupling was applied to obtain products
6a–6f and 6m–6s.
19a
19b
19c
19d
19e
19f
H
OCH3
F
OCH3 CH3
OCH3 C2H5
H
H
H
53
18
72
59
26
94
10
4644
5291
2675
ndb
>2700
ndb
>20,000 ndb
16,330
19,640
>20,000 871
45 <6
455
OCH3 Cyclopropyl
OCH3 Methoxyethyl
ndb
19g
19h SR6494 OCH3 Dimethylamino ethyl 0.4
a
IC50 values are means of two or more experiments with standard deviation
650%.
b
Not determined.
Table 5
Selectivity studies over other kinases, IC50 (nM)a
ID
ROCK-II
PKA
ROCK-I
MRCK
a
JNK3
p38
6s
19e
19h
0.9
26
0.4
765
16,330
45
2
180
3.5
9552
7861
247
5456
>20,000
13,760
>20,000
>20,000
>20,000
Scheme 2. Reagents and conditions: (a) NaBO3Á4H2O, CH3COOH, 70 °C, 76%; (b)
amine or alcohol nucleophilic reagents, inorganic bases, DMF, 0 °C to rt, 63–82%.
a
Data are means of two or more measurements with standard deviation 625%.
Scheme 1. Reagents and conditions: (a) (4-methoxyphenyl)methanethiol, K2CO3, DMF, rt, 92%; (b) SnCl2Á2H2O, EtOAc, rt, 86%; (c) chroman-3-carbonyl chlorides, pyridine,
CH2Cl2, 0 °C; (d) TFA, microwave, 160 °C; (e) boronic acid, Ph(PPh3)4, K2CO3, dioxane, H2O, 95 °C; or (i) bis-pinacolatodiboron, PdCl2(dppf), KOAc, dioxane, reflux; (ii) Ar–Br,
Ph(PPh3)4, dioxane, K2CO3, H2O, 95 °C, 60–80% in two steps.

Y. Yin et al. / Bioorg. Med. Chem. Lett. 19 (2009) 6686–6690
6689
Scheme 3. Reagents and conditions: (a) ethyl oxalyl chloride, pyridine, CH2Cl2, 0 °C, 76%; (b) TFA, microwave, 160 °C, 30 min; (c) NaOH, MeOH, H2O, rt; (d) oxalyl chloride,
DMF, CH2Cl2/amine, pyridine, CH2Cl2, 0 °C; (e) 1H-pyrazoleboronic acid pinacol ester, Ph(PPh3)4, K2CO3, dioxane, H2O, 95 °C, 45–63% in four steps.
Benzothiazoles 6g–6l were synthesized via intermediates 13 or
14 which were prepared as shown in Scheme 2. In the presence of
excess sodium perborate tetrahydrate, 4-bromo-2,6-difluoroani-
line (12) was oxidized to nitrobenzene 13. Nucleophilic substitu-
tion of one of the fluorines afforded 14. Compounds 6g–6l were
prepared using 14 and the chemistry described in Scheme 1.
Synthesis of compound 19 (Scheme 3) began with the acylation
of aniline 8 with ethyl oxalyl chloride to give 2-oxoacetate 15.
Microwave-assisted thiol deprotection and cyclization in TFA pro-
duced benzothiazole-2-carboxylate 16, which was hydrolyzed to
acid 17. Finally, amide formation with substituted or unsubstituted
benzyl amines, followed by Suzuki–Miyaura coupling, gave com-
pound 19.
the P-loop which is composed of the side chains of Phe103,
Leu123 and Phe136.
In conclusion, a series of potent and selective ROCK-II inhibitors
based on the benzothiazole scaffold were developed. Compounds
6s (SR6074) and 19h (SR6494) were demonstrated to be highly po-
tent and selective ROCK inhibitors. Future optimizations of these
compounds will be mainly focused on issues such as physicochem-
ical properties, toxicity, and selectivity against other undesirable
protein targets (and a few selected inhibitors will be subjected to
large panel counterscreens).
Acknowledgments
To help understand the binding motif of our benzothiazole
based ROCK inhibitors, inhibitor SR6494 was docked into the cat-
alytic domain of a homology ROCK-II model by methods described
previously.11c The enzyme–ligand complex with the lowest dock-
ing energy is shown in Figure 2. In this mode, the pyrazole group
forms two hydrogen bonds with the enzyme: one between the
backbone carbonyl group of Glu170 and the hydrogen atom of
NH on the pyrazole ring, another between the backbone amino
group of Met172 and another nitrogen atom of the pyrazole ring.
A third hydrogen bond is formed in the phosphate binding site be-
tween the amine side chain of Lys121 and the carboxamide car-
bonyl group of SR6494. A fourth hydrogen bond is formed
between the carbonyl group of Asp232 and the protonated tertiary
amine of the dimethylaminoethyl moiety of the inhibitor. In addi-
tion to these hydrogen bonding interactions, another factor to the
high potency of SR6494 is the hydrophobic interaction between
the benzyl amide phenyl ring and the hydrophobic pocket under
We thank Professor Patrick Griffin and Professor William Roush
for their support. We also acknowledge the resources from the Uni-
versity of Miami Center for Computational Science (CCS publica-
tion #158).
References and notes
1. Nakagawa, O.; Fujisawa, K.; Ishizaki, T.; Saito, Y.; Nakao, K.; Narumiya, S. FEBS
Lett. 1996, 392, 189.
2. (a) Leung, T.; Chen, X. Q.; Manser, E.; Lim, L. Mol. Cell. Biol. 1996, 16, 5313; (b)
Uehata, M.; Ishizaki, T.; Satoh, H.; Ono, T.; Kawahara, T.; Morishita, T.;
Tamakawa, H.; Yamagami, K.; Inui, J.; Maekawa, M.; Narumiya, S. Nature 1997,
389, 990; (c) Somlyo, A. P.; Somlyo, A. V. J. Physiol. 2000, 522, 177; (d) Riento, K.;
Ridley, A. J. Nat. Rev. Mol. Cell. Biol. 2003, 4, 446.
3. (a) Tanihara, H.; Inatani, M.; Honjo, M.; Tokushige, H.; Azuma, J.; Araie, M. Arch.
Ophthalmol. 2008, 126, 309; (b) Whitlock, N. A.; Harrison, B.; Mixon, T.; Yu, X.;
Wilson, A.; Gerhardt, B.; Eberhart, D. E.; Abuin, A.; Rice, D. S. J. Ocul. Pharmacol.
Ther. 2009, 25, 187; (c) Fukunage, T.; Ikesugi, K.; Nishio, M.; Sugimoto, M.;
Sasoh, M.; Hidaka, H.; Uji, Y. Curr. Eye Res. 2009, 34, 42.
4. (a) Gosens, R.; Schaafsma, D.; Nelemans, S. A.; Halayko, A. J. Mini-Rev. Med.
Chem. 2006, 6, 339; (b) Schaafsma, D.; Gosens, R.; Zaagsma, J.; Halayko, A. J.;
Meurs, H. Eur . J. Pharmacol. 2008, 585, 398.
5. Sun, X.; Minohara, M.; Kikuchi, H.; Ishizu, T.; Tanaka, M.; Piao, H.; Osoegawa,
M.; Ohyagi, Y.; Shimokawa, H.; Kira, J. I. J. Neuoimmunol. 2006, 180, 126.
6. (a) Rikitake, Y.; Kim, H. H.; Huang, Z.; Seto, M.; Yano, K.; Asano, T.; Moskowitz,
M. A.; Liao, J. K. Stroke 2005, 36, 2251; (b) Shin, H. K.; Salomone, S.; Ayara, C.
Exp. Opin. 2008, 1547.
7. Ying, H.; Biroc, S.; Li, W. W.; Alicke, B.; Xuan, J. A.; Pagila, R.; Ohashi, Y.; Okada,
T.; Kamata, Y.; Dinter, H. Mol. Cancer Ther. 2006, 5, 2158.
8. Park, K.; Kim, S. W.; Rhu, K. S.; Paick, J. S. J. Sex Med. 2006, 3, 996.
9. Shimokawa, H.; Takeshita, A. Arterioscler. Throm. Vasc. Biol. 2005, 25, 1767.
10. (a) Gingras, K.; Avedissian, H.; Thouin, E.; Boulanger, V.; Essagian, C.;
McKerracher, L.; Lubell, W. Bioorg. Med. Chem. Lett. 2004, 14, 4931; (b)
Takami, A.; Iwakubo, M.; Okada, Y.; Kawata, T.; Odai, H.; Takahashi, N.; Shindo,
K.; Kimura, K.; Tagami, Y.; Miyake, M.; Fukushima, K.; Inagaki, M.; Amano, M.;
Kaibuchi, K.; Iijima, H. Bioorg. Med. Chem. 2004, 12, 2115; (c) Iwakubo, M.;
Takami, A.; Okada, Y.; Kawata, T.; Tagami, Y.; Ohashi, H.; Sato, M.; Sugiyama, T.;
Fukushima, K.; Iijima, H. Bioorg. Med. Chem. 2007, 15, 350; (d) Iwakubo, M.;
Takami, A.; Okada, Y.; Kawata, T.; Tagami, Y.; Ohashi, H.; Kawata, T.; Tagami, Y.;
Sato, M.; Sugiyama, T.; Fukushima, K.; Taya, S.; Amano, M.; Kaibuchi, K.; Iijima,
H. Bioorg. Med. Chem. 2007, 15, 1022; (e) Stavenger, R.; Cui, H.; Dowdell, S.;
Franz, R.; Gaitanopoulos, D.; Goodman, K.; Hilfiker, M.; Ivy, R.; Leber, J.; Marino,
J.; Oh, H.; Viet, A.; Xu, W.; Ye, G.; Zhang, D.; Zhao, Y.; Jolivette, L.; Head, M.;
Semus, S.; Elkins, P.; Kirkpatrick, R.; Dul, E.; Khandekar, S.; Yi, T.; Jung, D.;
Wright, L.; Smith, G.; Behm, D.; Doe, C.; Bentley, R.; Chen, Z.; Hu, E.; Lee, D. J.
Figure 2. Model of SR6494 docked in the catalytic domain of ROCK-II.

6690
Y. Yin et al. / Bioorg. Med. Chem. Lett. 19 (2009) 6686–6690
Med. Chem. 2007, 50, 2; (f) Goodman, K.; Cui, H.; Dowdell, S.; Gaitanopoulos, D.;
Schürer, S. C.; Inoue, T.; Rao, V.; Schröter, T.; LoGrasso, P. J. Med. Chem. 2008, 51,
6642; (d) Sessions, E. H.; Yin, Y.; Bannister, T.; Weiser, A.; Griffin, E.; Pocas, J.;
Cameron, M.; Ruiz, C.; Lin, L.; Schürer, S. C.; Schröter, T.; LoGrasso, P.; Feng, Y.
Bioorg. Med. Chem. Lett. 2008, 18, 6390; (e) LoGrasso, P.; Feng, Y. Curr. Top. Med.
Chem. 2009, 9, 704.
Ivy, R.; Sehon, C.; Stavenger, R.; Wang, G.; Viet, A.; Xu, W.; Ye, G.; Semus, S.;
Evans, C.; Fries, H.; Jolivette, L.; Kirkpatrick, R.; Dul, E.; Khandekar, S.; Yi, T.;
Jung, D.; Wright, L.; Smith, G.; Behm, D.; Bentley, R.; Doe, C.; Hu, E.; Lee, D. J.
Med. Chem. 2007, 50, 6; (g) Sehon, C.; Wang, G.; Viet, A.; Goodman, K.; Dowdell,
S.; Elkins, P.; Semus, S.; Evans, C.; Jolivette, L.; Kirkpatrick, R.; Dull, E.;
Khandekar, S.; Yi, T.; Wright, L.; Smith, G.; Behm, D.; Bentley, R.; Doe, C.; Hu, E.;
Lee, D. J. Med. Chem. 2008, 51, 6631; (h) Schirok, H.; Kast, R.; Figueroa-Pérez, S.;
Bennabi, S.; Gnoth, M. J.; Feurer, A.; Heckroth, H.; Thutewohl, M.; Paulsen, H.;
Knorr, A.; Hütter, J.; Lobell, M.; Münter, K.; Geib, V.; Ehmke, H.; Lang, D.;
Radtke, M.; Mittendorf, J.; Stasch, J. P. ChemMedChem 2008, 3, 1893.
12. % Inhibition of CYP450 isoforms 1A2/2C9/2D6/3A4 at 10
lM was 2/10/28/-14.
13. Schröter, T.; Griffin, E.; Weiser, A.; Feng, Y.; LoGrasso, P. Biochem. Biophys. Res.
Commun. 2008, 374, 356.
14. Although the corresponding compound of 6l with a secondary amine (NH)
linkage (instead of the tertiary amine linkage in 6l) was not prepared and
evaluated, compounds with this side chain (dimethylaminoethylamine-) were
synthesized in closely related series and were discovered to have much
reduced ROCK potency.
15. In vivo pharmacokinetic data were obtained in rats from three determinations
with standard deviation 620%.
11. (a) Feng, Y.; Cameron, M.; Frackowiak, B.; Griffin, E.; Lin, L.; Ruiz, C.; Schröter,
T.; LoGrasso, P. Bioorg. Med. Chem. Lett. 2007, 17, 2355; (b) 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; (c) Feng, Y.; Yin, Y.; Weiser, A.; Griffin, E.; Cameron, M.; Lin, L.; Ruiz, C.;