Development of macrocyclic inhibitors of HCV NS3/4A protease with cyclic constrained P2-P4 linkers

Article abstract of DOI:10.1016/j.bmcl.2012.09.061

A series of macrocyclic compounds containing a cyclic constraint in the P2-P4 linker region have been discovered and shown to exhibit excellent HCV NS3/4a genotype 3a and genotype 1b R155 K, A156T, A156 V, and D168 V mutant activity while maintaining high rat liver exposure. The effect of the constraint is most dramatic against gt 1b A156 mutants where ～20-fold improvements in potency are achieved by introduction of a variety of ring systems into the P2-P4 linker.

Full text of DOI:10.1016/j.bmcl.2012.09.061

Bioorganic & Medicinal Chemistry Letters 22 (2012) 7207–7213
Contents lists available at SciVerse ScienceDirect
Bioorganic & Medicinal Chemistry Letters
journal homepage: www.elsevier.com/locate/bmcl
Development of macrocyclic inhibitors of HCV NS3/4A protease with cyclic
constrained P2–P4 linkers
Michael T. Rudd a, , Charles J. McIntyre a, Joseph J. Romano a, John W. Butcher a, M. Katharine Holloway d,
⇑
Kimberly Bush a, Kevin T. Nguyen a, Kevin F. Gilbert a, Terry A. Lyle a, Nigel J. Liverton a, Bang-Lin Wan a,
Vincenzo Summa e, Steven Harper e, Michael Rowley e, Joseph P. Vacca a, Steven S. Carroll b,
Christine Burlein b, Jillian M. DiMuzio b, Adam Gates b, Donald J. Graham b, Qian Huang b,
Steven W. Ludmerer b, Stephanie McClain b, Carolyn McHale b, Mark Stahlhut b, Christine Fandozzi c,
Anne Taylor c, Nicole Trainor c, David B. Olsen b, John A. McCauley a
a Departments of Medicinal Chemistry, Merck Research Laboratories West Point, PA 19486, USA
b Antiviral Research, Merck Research Laboratories West Point, PA 19486, USA
c Drug Metabolism, Merck Research Laboratories West Point, PA 19486, USA
d Chemistry Modeling and Informatics, Merck Research Laboratories West Point, PA 19486, USA
e Department of Medicinal Chemistry, IRBM, Merck Research Laboratories, Rome, Italy
a r t i c l e i n f o
a b s t r a c t
Article history:
Available online 2 October 2012
A series of macrocyclic compounds containing a cyclic constraint in the P2–P4 linker region have been
discovered and shown to exhibit excellent HCV NS3/4a genotype 3a and genotype 1b R155 K, A156T,
A156 V, and D168 V mutant activity while maintaining high rat liver exposure. The effect of the con-
straint is most dramatic against gt 1b A156 mutants where ꢀ20-fold improvements in potency are
achieved by introduction of a variety of ring systems into the P2–P4 linker.
Keywords:
Hepatitis C
NS3/4A protease
Macrocycle
Ó 2012 Elsevier Ltd. All rights reserved.
P2–P4 linker
Cyclic constraint
Hepatitis C is a chronic infection caused by the hepatitis C virus
(HCV) which primarily replicates in the liver, affects 130–170 mil-
lion people worldwide and is the leading indication for liver trans-
plantation.1,2 HCV displays a high degree of genetic heterogeneity
with six major genotypes (gt) that have different geographic distri-
butions. Genotypes 1, 2 and 3 represent more than 90% of the
infections in the developed world. While HCV can be treated with
As we have previously published, our molecular modeling-de-
rived strategy resulted in the development of an alternative to
the P1–P310 macrocyclic core which contains a novel P2–P4 link-
age,11 and which led to the discovery of vaniprevir,12,13 (Fig. 1)
and MK-1220.14
We have also recently disclosed that improving potency against
gt 3a and clinically relevant gt 1 mutant viruses motivated our pur-
suit of second generation compounds which led to the discovery of
MK-5172.15,16 Most recently, we described the discovery of
another series of second generation compounds with excellent gt
a regimen of co-dosing pegylated IFN-a and ribavirin for up to one
year, severe side-effects are produced and this regimen is only
moderately effective.3,4 Efforts toward improved HCV treatment
include the development of direct antivirals which inhibit key
steps in the viral replication process. One such target is inhibition
of HCV NS3/4A protease; a serine protease that is critical for viral
replication.5,6 Clinical proof of concept was established by Boehrin-
ger-Ingelheim with BILN-2061,7 while subsequently, both Merck
(SCH-503034, boceprevir9) and Vertex (VX-950, telaprevir8) have
gained FDA approval for HCV NS3/4A inhibitors which are dosed
in combination with interferon and ribavirin.
P2
O
N
O
O
N
O
O
O
O
O
O
O
O
N
N
H
N
H
S
S
O
HN
O
O
HN
N
N
O
N
O
O
H
H
P4
O
O
P1
P3
Vaniprevir (MK-7009)
1
⇑
Corresponding author.
E-mail address: michael_rudd@merck.com (M.T. Rudd).
Figure 1. Representative Merck P2–P4 macrocyclic HCV protease NS3/4a inhibitors.
0960-894X/$ - see front matter Ó 2012 Elsevier Ltd. All rights reserved.
http://dx.doi.org/10.1016/j.bmcl.2012.09.061

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M. T. Rudd et al. / Bioorg. Med. Chem. Lett. 22 (2012) 7207–7213
Table 1
2-Ethoxyquinoline carbamate constrained linkers
O
N
O
O
9a-9f; R = cyclopentyl
10a-10c; R = cyclohexyl
O
O
O
N
H
N
S
HN
N
O
O
H
O
R
Linkere
R
3a Kia (nM)
gt 1b repliconb (nM)
(50% NHS)
gt 1b Kia (nM)
[liver]4h (l
M)
c
#
R155K
1.3
A156T
A156V
—
1
Cyclopentyl
Cyclopentyl
Cyclohexyl
Cyclohexyl
Cyclopentyl
2.2
4.6
3.1
12.6
4.1
11
17
55
25
38
41
0.8
2.0
42
49
35
O
O
O
9a
10a
10b
9b
0.5
1.3
1.5
0.9
15
40
567
—
10.2
37.1
—
O
—
O
9cd
Cyclopentyl
5.0
24
2.0
4.6
46
—
O
10c
9dd
Cyclohexyl
Cyclopentyl
1.9
18
18
—
0.5
2.2
0.7
52
23
—
0.3
—
O
O
O
9ee
Cyclopentyl
Cyclopentyl
7.7
1.0
16
11
2.4
0.2
4.8
2.8
16
14
—
OH
O
9fe
27.0
a
b
c
NS3/4a protease time-resolved fluorescence assay; all gt 1b Ki < 0.05 nM.
Cell-based replicon assay IC50; in presence of 50% NHS.
5 mg/kg dosed orally in PEG400 (n = 2, rat), liver levels after 4 h.
Mixture of stereoisomers.
d
e
Single isomer; absolute stereochemistry not established.
3a potency; exemplified by 1 (Fig. 1).17 Compound 1 has an excel-
lent gt 1b and 3a potency (1b Ki = 0.03 nM; 3a Ki = 2.2 nM), good
cellular activity (1b replicon IC50 with 50% NHS = 11 nM) and
excellent liver exposure in rat following a 5 mg/kg oral dose
([liver]4h = 35,000 nM). Obtaining high and sustained liver expo-
sure likely is important to the success of anti-HCV compounds as

M. T. Rudd et al. / Bioorg. Med. Chem. Lett. 22 (2012) 7207–7213
7209
the liver is the primary HCV replication site,18 and optimizing for
high liver concentrations in preclinical species became the focus
of our preliminary pharmacokinetic studies; initial assessment of
liver exposure was to measure the concentration of compound
present in rat liver 4 h after a 5 mg/kg oral dose. While 1 also
has excellent potency versus common gt 1 mutants (1b R155 K
Ki = 1.3 nM; 1b D168 V Ki = 2.2 nM), it loses significant potency
against gt 1b A156 mutant enzymes (1b A156T Ki = 41 nM, Table 1),
and a key target of our next-generation program was to improve
potency against both gt 3 and key gt 1 mutant enzymes, therefore
futher improvments were desired. While the R155K mutant arises
in gt 1a clinically, we typically screened against the gt 1b mutant in
order to maintain a consistant background. For compounds where
we have data for both gt 1a and 1b R155K, the Ki values are similar.
Herein, we describe the discovery of a series of potent HCV NS3/4a
protease inhibitors which achieve the goal of improved potency
against both gt 3a and gt 1 mutant enzymes due to the presence
of a cyclic constraint in the P2–P4 linker region.
During the SAR development which led to the identification of
1, we also examined the effect of alternative carbamates and ureas
on our P2–P4 scaffold given the P4 structural diversity seen in the
literature for P1–P3 macrocycles and non-macrocyclic cores6 One
commonly used P4 group is the cyclopentyl carbamate present in
BILN-2061, and incorporation of this group into our P2-P4 linker
led to compound 9a (Table 1). Compared to 1, 9a lost approxi-
mately twofold gt 3a potency, but in addition to maintaining activ-
ity against gt 1b (Ki < 0.016 nM) and gt 1b R155 K (Ki = 0.5 nM), the
activity against gt 1b A156T improved >40-fold (Ki = 0.8 nM) while
still maintaining reasonable rat liver exposure (10 lM). This
dramatic increase in potency seen with the addition of a fused-
cyclopentane ring led us to investigate the origin via a molecu-
lar-modeling study, and while we do not completely understand
this effect, some potential insight was gained. A comparison of
low-energy models of 1 and constrained analog 9a in the gt 1b
HCV NS3/4a site (Fig. 2A) suggests that 9a can adopt a priori a
slightly more open conformation. Further examination of 1 and
9a in a model of the A156T mutant site (Fig. 2B) indicates that in
addition 9a can more readily modulate the shape and positioning
of the macrocyclic ring as it sits atop the increased bulk of the
T156 side-chain. A global increase in gt 1b potency due to reduced
entropy loss upon binding is another possible explanation.
Figure 2. Low energy models of 1 (green) and 9a (magenta) in the gt 1b HCV NS3/
4a active site (A) and a model of the A156T mutant active site (B). 156 residues
highlighted in orange.
The effects of cyclic constraints in the P2–P4 linker were further
probed by examining the SAR of these linkers. The desired macro-
cycles were prepared by a similar method detailed in our previous
BsO
O
N
O
O
CO2Me
O
N
O
N
O
NH2
4
Br
Boc
a, b
c
Br
Br
2
OH
5
CO2Me
O
3
N
Boc
O
N
O
O
N
d, e, f
g, h, i
O
O
O
CO2Me
H
N
N
O
O
O
H
O
S
N
O
O
6
CO2H
O
H
O
N
S
O
HN
H2N
HCl
O
N
N
N
O
O
H
O
H
O
8
7
9a
Scheme 1. Reagents and conditions: (a) ethyl 3-ethoxy-3-iminopropanoate hydrochloride (84%); (b) dowtherm, 250 C (84%) (c) NMP, Cs2CO3 (77%); (d) EtOH, Et3N, 5%
Pd(dppf)Cl2, (CH2@CH2BF3)K, reflux (91%) (e) HCl/dioxane; (f) HATU, DMF, DIEA, 6 (86% over 2 steps); (g) 10% Zhan 1b,22 DCE, 45 °C (91%); (h) LiOH, THF, MeOH, water (91%);
(i) HATU, DMF, DIEA, 8 (74%).

7210
M. T. Rudd et al. / Bioorg. Med. Chem. Lett. 22 (2012) 7207–7213
Table 2
2-Ethoxyquinoline urea constrained linkers
O
N
O
O
11a-11b; R = cyclopentyl
12a-12f; R = cyclohexyl
O
O
O
N
H
N
S
HN
N
O
O
H
O
R
c
#
Linker
R
3a Kia (nM)
gt 1b repliconb (nM)
(50% NHS)
gt 1b Kia (nM)
[liver]4h (lM)
R155K
0.6
A156T
A156V
18
11a
Cyclopentyl
1.5
25
43
1.7
0.4
15.9
N
O
N
12a
Cyclohexyl
1.4
0.2
6.8
4.8
O
N
12b
12c
12d
Cyclohexyl
Cyclohexyl
Cyclohexyl
3.6
2.3
5.2
29
23
9.0
0.3
1.2
1.0
2.4
1.9
6.9
134
46
—
—
O
N
4.4
—
O
N
12e
Cyclohexyl
2.1
32
0.2
0.7
18
11.0
O
N
12f
Cyclohexyl
Cyclopentyl
0.9
1.0
64
18
0.2
0.9
0.2
7.1
6.1
4.0
O
N
11b
—
—
O
N
a
b
c
NS3/4a protease time-resolved fluorescence assay; all gt 1b Ki < 0.05 nM.
Cell-based replicon assay IC50; in presence of 50% NHS.
5 mg/kg dosed orally in PEG400 (n = 2, rat), liver levels after 4 h.
publications11,12,14 and exemplified for 9a in Scheme 1 (see Supple-
mentary data for selected procedures). Condensation of 4-bromo-
3-methoxyaniline with diethylmalonate proceeds smoothly to give
key heterocycle 3 used in the preparation of compounds 9–12.
Addition to the activated hydroxyproline derivative 4 leads to 5,
which is deprotected and coupled to carbamate-acid 6 (prepared

M. T. Rudd et al. / Bioorg. Med. Chem. Lett. 22 (2012) 7207–7213
7211
Table 3
P2 2-alkoxy quinolines with constrained linkers
O
N
13a-13d; R = cyclopentyl
14a-14b; R = cyclohexyl
O
O
O
O
N
H
N
S
HN
N
O
O
H
O
R
c
#
Linker
R
3a Kia (nM)
gt 1b repliconb (nM)
(50% NHS)
gt 1b Kia (nM)
[liver]4h
(lM)
R155K
0.2
A156T
A156V
—
13a
Cyclopentyl
11.6
58
17
30.8
O
13b
13c
Cyclopentyl
Cyclopentyl
5.7
3.0
5.0
0.1
0.1
7.8
64
37
—
O
O
O
N
32
31
2.9
1.5
8.6
O
N
13d
Cyclopentyl
5.9
0.1
22
12.0
14a
14b
Cyclohexyl
Cyclohexyl
27
38
—
—
0.3
0.5
11
28
—
—
—
—
O
N
O
N
a
b
c
NS3/4a protease time-resolved fluorescence assay; all gt 1b Ki < 0.05 nM.
Cell-based replicon assay IC50; in presence of 50% NHS.
5 mg/kg dosed orally in PEG400 (n = 2, rat), liver levels after 4 h.
in 4 steps). Vinylation,19 ring-closing metathesis,20 ester hydroly-
sis, and coupling to known21 vinylcyclopropyl amine 8 leads to
macrocycle 9a. For analogs 11, 12, 13c–13d, and 14a–14b, the cor-
responding urea-containing carboxylic acids can be substituted in
place of 6 in step d. Alternative P2 7-methoxyquinoline containing
compounds 13 and 14 can be obtained using a similar procedure.
Replacement of the P3-cyclopentyl group in 9a with a cyclohex-
ane (10a, Table 1) leads to a approximately twofold loss in gt1b
A156T/V potency and a slight improvement in gt 3a potency and
rat liver exposure, but overall gives a similar profile and we gener-
ally used these groups interchangeably. As we have published pre-
viously,12,14 the increased lipophilicity of the P3-cyclohexyl often
leads to improved liver exposure, but sometimes decreases in gt
1b replicon potency in the presence of 50% NHS are seen. Expan-
sion of the fused ring in the P2–P4 linker to a cyclohexane (10b)
leads to a decrease in both gt 3a and gt 1b A156T activity. The tight
SAR around gt 1b A156T potency is again demonstrated via
introduction of a methyl group beta to the carbamate oxygen in

7212
M. T. Rudd et al. / Bioorg. Med. Chem. Lett. 22 (2012) 7207–7213
Table 4
Key compound comparison.
b
#
1b Kia (nM)
2a Kia (nM)
3a Kia (nM)
1b replicon IC50 (nM)
gt 1b Kia (nM)
A156T A156V
10% FBS
50% NHS
R155K
D168V
1
9f
13c
0.016
0.016
0.016
0.14
0.14
0.17
2.1
1.3
3.1
2.0
2.3
3.1
11
11
32
1.2
0.2
0.1
41
2.8
2.9
—
14
37
2.2
1.8
1.2
a
NS3/4a protease time-resolved fluorescence assay.
Cell-based replicon assay.
b
9a leading to 9b. While 9b maintains similar gt 3a activity, gt 1b
A156T potency is decreased >40x.
series (Table 3), with the modification that given the altered orien-
tation of the P2 group, the number of atoms connecting the linker
ring to the P2 group was generally increased by 2 atoms. While
introduction of two of the better carbamate linkers (13a, 13b)
led to only moderate gt 3a and gt 1b A156T/V potency, introduc-
tion of an alkoxypyrrolidine urea (13c, 13d) gave compounds with
good overall profiles in terms of potency and rat liver exposure.
13c (Ki = 3 nM) is twofold more potent than 13d against gt 3a
(Ki = 5.9 nM), but is somewhat less potent at gt 1b A156 mutants.
With the same linker length, this high level of potency was not
maintained with piperidine (14a) and azetidine (14b) analogs as
gt 3a and gt 1b A156T potency fell ꢀ10-fold.
In contrast, changing the cyclopentane linkage from 1,2 to 1,3
(9c) leads to a similar, but slightly less potent overall profile. Tet-
rahydrofuran derivative 10c has very similar potency to 9a, but
loses nearly all liver exposure. Further contraction of cyclic con-
straint to 1,2- and 1,3-cyclobutane (9d, 9e) leads to different pro-
files. 1,2-cyclobutane 9d loses potency versus gt 3a and gt 1b
A156T, while the 1,3-linked isomer 9e has moderate gt 3a activity,
but good potency versus A156 mutants, including only a ꢀ3x shift
going from A156T to A156V. Moving the fused ring constraint adja-
cent to the P2 heterocycle led to a compound with the most bal-
anced overall profile within this sub-series. Cyclopropyl analog 9f
possesses excellent gt 3a (Ki = 1 nM) potency, gt 1b replicon activ-
ity (IC50 = 11 nM), and rat liver exposure (27,000 nM @ 4 h, 5 mpk).
In terms of gt 1b mutant activity, 9f displays <15 nM Ki against
both A156T (2.8 nM) and A156V (14 nM) while maintaining sub-
nanomolar activity against gt 1b R155K.
In summary, we have discovered a general effect across two dif-
ferent P2 series wherein introduction of various cyclic constraints
in the P2–P4 linker region led to improved gt 1b mutant and gt
3a potency profiles. Within these series, we optimized for balanced
potency across gt 1b mutants and gt 3a as well as rat liver expo-
sure,23 and identified several promising compounds. Table 4 shows
further comparison of two of the more potent analogs across geno-
types 1-3 and additional mutant viruses, with 9f and 13c both pos-
sessing sub-nanomolar to low-nanomolar potency across
genotypes 1, 2, and 3, as well as three different key mutation posi-
tions (R155, A156, D168). Overall, these molecules possess preclin-
ical potency profiles of next-generation inhibitors of HCV NS3/4a
protease.
In order to further investigate the SAR of this P2–P4 ring con-
straint effect, we also explored urea containing linkers (Table 2).
As we have reported previously, the P2–P4 carbamate linker can
also be effectively replaced with a urea,11 and in this case, simple
substitution of N-methyl for the oxo in 9a leads to 11a which dis-
plays
a similar profile, but with increased gt 3a potency
(Ki = 1.5 nM) and a twofold loss in gt 1b A156T activity. With the
promising profile of 11a in hand, we decided to exploit different
conformational space and link directly through a cyclic trialkyl
nitrogen (11b, 12a–12f). Due to this change in urea attachment po-
sition, the number of atoms connecting the linker ring to the P2 het-
erocycle was generally increased from three to four. 3-
Alkoxypyrrolidine isomers 12a and 12b both offer good potency
against gt 3a, gt 1b R155K, and gt 1b A156T, but (R)-isomer 12b loses
considerable A156V potency. While (S)-isomer 12a has an excellent
biochemical potency profile, it shifts considerably in the gt 1b rep-
licon assay in the presence of 50% NHS (43 nM) and also only has
Acknowledgments
We thank Dr. Charles W. Ross, III for high-resolution mass spec-
tra data and Sandor L. Varga for interpretation of NMR spectra.
Supplementary data
Supplementary data associated with this article can be found, in
the online version, at http://dx.doi.org/10.1016/j.bmcl.2012.
09.061.
moderate rat liver exposure (4.8 lM). Ring-expanded analog 12c
is more potent in the gt 1b replicon assay, but loses approximately
sixfold against gt 1b A156V and does not have improved rat liver
exposure. While morpholine analog 12d loses some gt 3a potency,
4-alkoxy-piperidine 12e maintains a favorable overall potency pro-
file while increasing liver levels greater than twofold compared to
12a. Contracting the ring by two carbons leads to azetidine analog
12f which has the best biochemical potency in this series, but loses
significant gt 1b replicon activity (64 nM) and has poor rat liver
exposure. Alternative azetidine analog 11b has improved gt 1b rep-
licon activity, but loses >30-fold gt 1b A156T potency relative to 12f.
As we disclosed recently,15 introduction of 3-quinoline P2
groups can lead to extremely potent analogs and MK-5172 resulted
from development of this sub-series. As was noted in that commu-
nication, the gt 3a potency of the closely related P2 2-quinoline
sub-series was lower when comparing analogs lacking constrained
linkers. However we were interested to examine if the potency of
P2 2-quinolines could be increased with introduction of one of
the more promising constrained linkers from the ethoxyquinoline
References and notes
1. WHO. Hepatitis C-Global prevalence (update) Wkly. Epidemiol. Reci 1999, 74,
425.
2. Liang, T. J.; Heller, T. Gastroenterology 2004, 127, S62.
3. Hadziyannis, S. J.; Sette, H., Jr.; Morgan, T. R.; Balan, V.; Diago, M.; Marcellin, P.;
Ramadori, G.; Bodenheimer, H., Jr.; Bernstein, D.; Rizzetto, M.; Zeuzem, S.;
Pockros, P. J.; Lin, A.; Ackrill, A. M. Ann. Intern. Med. 2004, 140, 346.
4. Fried, M. W. Hepatology 2002, 36, S237.
5. Moradpour, D.; Penin, F.; Rice, C. M. Nature Rev. Microbio. 2007, 5, 453.
6. Chen, K. X.; Njoroge, F. G. Curr. Opin. Inv. Drugs 2009, 10, 821.
7. Lamarre, D.; Anderson, P. C.; Bailey, M.; Beaulieu, P.; Bolger, G.; Bonneau, P.;
Boes, M.; Cameron, D. R.; Cartier, M.; Cordingley, M. G.; Faucher, A.-M.;
Goudreau, N.; Kawai, S. H.; Kukolj, G.; Lagace, L.; LaPlante, S. R.; Narjes, H.;
Poupart, M.-A.; Rancourt, J.; Sentjens, R. E.; Roger, St,G.; Simoneau, B.;
Steinmann, G.; Thibeault, D.; Tsantrizos, Y. S.; Weldon, S. M.; Yong, C.-L.;
Llinas-Brunet, M. Nature 2003, 426, 186.
8. Perni, R. B.; Almquist, S. J.; Byrn, R. A.; Chandorkar, G.; Chaturvedi, P. R.;
Courtney, L. F.; Decker, C. J.; Dinehart, K.; Gates, C. A.; Harbeson, S. L.; Heiser, A.;
Kalkeri, G.; Kolaczkowski, E.; Lin, K.; Luong, Y.-P.; Rao, B. G.; Taylor, W. P.;
Thomson, J. A.; Tung, R. D.; Wei, Y.; Kwong, A. D.; Lin, C. Antimicrob. Agents
Chemother. 2006, 50, 899.

M. T. Rudd et al. / Bioorg. Med. Chem. Lett. 22 (2012) 7207–7213
7213
9. Malcolm, B. A.; Liu, R.; Lahser, F.; Agrawal, S.; Belanger, B.; Butkiewicz, N.;
Chase, R.; Gheyas, F.; Hart, A.; Hesk, D.; Ingravallo, P.; Jiang, C.; Kong, R.; Lu, J.;
Pichardo, J.; Prongay, A.; Skelton, A.; Tong, X.; Venkatraman, S.; Xia, E.;
Girijavallabhan, V.; Njoroge, F. G. Antimicrob. Agents Chemother. 2006, 1013, 50.
10. For examples of other P1-P3 macrocycles see TMC435350: (a) Lin, T.-I.; Lenz,
O.; Fanning, G.; Verbinnen, T.; Delouvroy, F.; Scholliers, A.; Vermeiren, K.;
Rosenquist, A.; Edlund, M.; Samuelsson, B.; Vrang, L.; Herman, De. K.;
Wigerinck, P.; Raboisson, P.; Simmen, K. Antimicrob. Agents Chemother. 2009,
53, 1377; (b) Raboisson, P.; Herman, K.; Rosenquist, A.; Nilsson, M.; Salvador-
Oden, L.; Lin, T.-I.; Roue, N.; Ivanov, V.; Wahling, H.; Wickstrom, K.; Hamelink,
E.; Edlund, M.; Vrang, L.; Vendeville, S.; Wim, V.; McGowan, D.; Tahri, A.; Hu, L.;
Boutton, C.; Lenz, O.; Delouvroy, F.; Pille, G.; Surleraux, D.; Wigerinck, P.;
Samuelsson, B.; Simmen, K. Bioorg. Med. Chem. Lett. 2008, 18, 4853. and ITMN-
191 (R7227); (c) Seiwert, S. D.; Andrews, S. W.; Jiang, Y.; Serebryany, V.; Tan,
H.; Kossen, K.; Rajagopalan, P. T. R.; Misialek, S.; Stevens, S. K.; Stoycheva, A.;
Hong, J.; Lim, S. R.; Qin, X.; Rieger, R.; Condroski, K. R.; Zhang, H.; Do, M. G.;
Lemieux, C.; Hingorani, G. P.; Hartley, D. P.; Josey, J. A.; Pan, L.; Beigelman, L.;
Blatt, L. M. Antimicrob. Agents Chemother. 2008, 52, 4432.
Carroll, S. S.; DiMuzio, J. M.; Graham, D. J.; Ludmerer, S. W.; Stahlhut, M. W.;
Fandozzi, C. M.; Trainor, N.; Olsen, D. B.; Vacca, J. P.; Liverton, N. ACS Med. Chem.
Lett. 2011, 2, 207.
15. Harper, S.; McCauley, J. A.; Rudd, M. T.; Ferrara, M.; DiFilippo, M.; Crescenzi, B.;
Koch, U.; Petrocchi, A.; Holloway, M. K.; Butcher, J. W.; Romano, J. J.; Bush, K. J.;
Gilbert, K. F.; McIntyre, C. J.; Nguyen, K. T.; Nizi, E.; Carroll, S. S.; Ludmerer, S.
W.; Burlein, C.; DiMuzio, J. M.; Graham, D. J.; McHale, C. M.; Stahlhut, M. W.;
Olsen, D. B.; Monteagudo, E.; Cianetti, S.; Giuliano, C.; Pucci, V.; Trainor, N.;
Fandozzi, C. M.; Rowley, M.; Coleman, P. J.; Vacca, J. P.; Summa, V.; Liverton, N.
J. ACS Med. Chem. Lett. 2012, 3, 332.
16. Summa, V.; Ludmerer, S. W.; McCauley, J. A.; Fandozzi, C.; Burlein, C.; Claudio,
G.; Coleman, P. J.; Dimuzio, J. M.; Ferrara, M.; Di, F. M.; Gates, A. T.; Graham, D.
J.; Harper, S.; Hazuda, D. J.; McHale, C.; Monteagudo, E.; Pucci, V.; Rowley, M.;
Rudd, M. T.; Soriano, A.; Stahlhut, M. W.; Vacca, J. P.; Olsen, D. B.; Liverton, N. J.;
Carroll, S. S. Antimicrob. Agents Chemother. 2012, 56, 4161.
17. Rudd, M. T.; McCauley, J. A.; Romano, J. J.; Butcher, J. W.; Bush, K.; McIntyre, C.
J.; Nguyen, K. T.; Gilbert, K. F.; Lyle, T. A.; Holloway, M. K.; Wan, B.-L.; Vacca, J.
P.; Summa, V.; Harper, S.; Rowley, M.; Carroll, S. S.; Burlein, C.; DiMuzio, J. M.;
Gates, A.; Graham, D. J.; Huang, Q.; Ludmerer, S. W.; McClain, S.; McHale, C.;
Stahlhut, M.; Fandozzi, C.; Taylor, A.; Trainor, N.; Olsen, D. B.; Liverton, N. J.
Bioorg. Med. Chem. Lett. 2012. http://dx.doi.org/10.1016/j.bmcl.2012.08.106.
18. Lindenbach, B. D.; Rice, C. M. Nature 2005, 436, 933.
11. Liverton, N. J.; Holloway, M. K.; McCauley, J. A.; Rudd, M. T.; Butcher, J. W.;
Carroll, S. S.; DiMuzio, J.; Fandozzi, C.; Gilbert, K. F.; Mao, S.-S.; McIntyre, C. J.;
Nguyen, K. T.; Romano, J. J.; Stahlhut, M.; Wan, B.-L.; Olsen, D. B.; Vacca, J. P. J.
Am. Chem. Soc. 2008, 130, 4607.
12. McCauley, J. A.; McIntyre, C. J.; Rudd, M. T.; Nguyen, K. T.; Romano, J. J.;
Butcher, J. W.; Gilbert, K. F.; Bush, K. J.; Holloway, M. K.; Swestock, J.; Wan, B.-
L.; Carroll, S. S.; DiMuzio, J. M.; Graham, D. J.; Ludmerer, S. W.; Mao, S.-S.;
Stahlhut, M. W.; Fandozzi, C. M.; Trainor, N.; Olsen, D. B.; Vacca, J. P.; Liverton,
N. J. J. Med. Chem. 2010, 53, 2443.
13. Liverton, N. J.; Carroll, S. S.; Dimuzio, J.; Fandozzi, C.; Graham, D. J.; Hazuda, D.;
Holloway, M. K.; Ludmerer, S. W.; McCauley, J. A.; McIntyre, C. J.; Olsen, D. B.;
Rudd, M. T.; Stahlhut, M.; Vacca, J. P. Antimicrob. Agents Chemother. 2010, 54,
305.
19. Molander, G. A.; Bernardi, C. R. J. Org. Chem. 2002, 67, 8424.
20. Lee, C. W.; Grubbs, R. H. J. Org. Chem. 2001, 66, 7155.
21. Wang, X. A.; Sun, L.-Q.; Sit, S. Y.; Scola, P. M. Hewawasam, P.; Good, A. C.; Chen,
Y.; Campbell, J. A. U.S. Patent 6995174, 2006.
22. Zhan 1b catalyst: Available from Strem Chemicals, catalog # 44–0082.
23. While liver exposure in other species was not routinely assessed, the predictive
nature of this rat liver screening paradigm for discovering compounds which
provide liver exposure in additional species within the P2–P4 macrocyclic
space has been demonstrated several times (see references for: vaniprevir,12,13
MK-1220,14 and MK-517215,16).
14. Rudd, M. T.; McCauley, J. A.; Butcher, J. W.; Romano, J. J.; McIntyre, C. J.;
Nguyen, K. T.; Gilbert, K. F.; Bush, K. J.; Holloway, M. K.; Swestock, J.; Wan, B.-L.;