Discovery of potent sulfonamide P4-capped ketoamide second generation inhibitors of hepatitis C virus NS3 serine protease with favorable pharmacokinetic profiles in preclinical species

Article abstract of DOI:10.1016/j.bmc.2010.01.044

Hepatitis is a disease characterized by inflammation of the liver, usually producing swelling and, in many cases, permanent damage to liver tissues. Viral hepatitis C (HCV), a small (+)-RNA virus, infects chronically 3% of the world's population. Boceprevir, SCH 503034, (1) our first generation HCV inhibitor, has already established proof-of- concept and is currently in late stage (phase III) clinical trials. In view of the positive data from our first generation compound, further work aimed at optimizing its overall profile was undertaken. Herein, we report that extension of our earlier inhibitor to the P₄ pocket by introducing a new sulfonamide moiety and optimization of the P1/P₁′ capping led to the discovery of a novel series of inhibitors of the HCV NS3 serine protease. Optimization of the P₁ residue significantly improved potency and selectivity. The combination of optimal moieties led to the discovery of compound 47 which, in addition to being a potent inhibitor of HCV subgenomic RNA replication, was also found to have good PK profile in rat, dog and monkey.

Full text of DOI:10.1016/j.bmc.2010.01.044

Bioorganic & Medicinal Chemistry 18 (2010) 1854–1865
Contents lists available at ScienceDirect
Bioorganic & Medicinal Chemistry
journal homepage: www.elsevier.com/locate/bmc
Discovery of potent sulfonamide P4-capped ketoamide second generation
inhibitors of hepatitis C virus NS3 serine protease with favorable
pharmacokinetic profiles in preclinical species
a
a
a
a
Stéphane L. Bogen a, , Ashok Arasappan , Francisco Velazquez , Melissa Blackman , Regina Huelgas ,
Weidong Pan a, Elise Siegel a, Latha G. Nair a, Srikanth Venkatraman a, Zhuyan Guo b, Ronald Doll a,
Neng-Yang Shih a, F. George Njoroge a
*
a Department of Medicinal Chemistry, Merck Research Labs, 2015 Galloping Hill Road, Kenilworth, NJ 07033, USA
b Department of Structural Chemistry, Merck Research Labs, 2015 Galloping Hill Road, Kenilworth, NJ 07033, USA
a r t i c l e i n f o
a b s t r a c t
Article history:
Hepatitis is a disease characterized by inflammation of the liver, usually producing swelling and, in many
cases, permanent damage to liver tissues. Viral hepatitis C (HCV), a small (+)-RNA virus, infects chroni-
cally 3% of the world’s population. Boceprevir, SCH 503034, (1) our first generation HCV inhibitor, has
already established proof-of- concept and is currently in late stage (phase III) clinical trials. In view of
the positive data from our first generation compound, further work aimed at optimizing its overall profile
was undertaken. Herein, we report that extension of our earlier inhibitor to the P4 pocket by introducing a
new sulfonamide moiety and optimization of the P1/P01 capping led to the discovery of a novel series of
inhibitors of the HCV NS3 serine protease. Optimization of the P1 residue significantly improved potency
and selectivity. The combination of optimal moieties led to the discovery of compound 47 which, in addi-
tion to being a potent inhibitor of HCV subgenomic RNA replication, was also found to have good PK pro-
file in rat, dog and monkey.
Received 14 January 2010
Accepted 16 January 2010
Available online 25 January 2010
Keywords:
HCV
Boceprevir
Ketoamide
Sulfonamide
Ó 2010 Elsevier Ltd. All rights reserved.
1. Introduction
tion of hepatitis C virons and assists in the processing of the HCV
polyprotein by cleaving four downstream sites. Because of its cen-
Hepatitis C is a major cause of acute hepatitis and the most pre-
valent liver disease. Viral hepatitis C (HCV), a small (+)-RNA virus,
infects chronically 3% of the world’s population and million are
newly infected each year. Because of mild symptoms, HCV has
been referred by many as stealth virus. It can hide in the cell, unde-
tected, for a long period of time and can take as long as 20 years to
go from infection to chronic liver disease. Untreated HCV infections
can progress to cirrhosis, hepatocellular carcinoma and liver fail-
ure, a primary cause for liver transplantation.1 Although the use
of alpha interferons is an integral component in the management
of chronic hepatitis C infection, major adverse events can occur
and subsequently result in dose reduction or discontinuation of
treatment.2 With the opportunity to improve response rates, espe-
cially for genotype 1 patients, and given the side effects associated
with the current therapy, it is necessary to search for novel, potent
and drug-like inhibitors of HCV with the intent of improving treat-
ment outcomes and potentially shorten treatment duration.3
The NS3 protease has demonstrated a vital role in the replica-
tion of the HCV virus. It is a pivotal enzyme required for matura-
tral role in viral replication,4 inhibition of HCV NS3 serine protease
has been actively pursued as target for antiviral therapy.5
Several NS3/4A protease inhibitors have been moved to human
clinical trials. The Boehringer Ingelheim group was the first one to
report phase Ib clinical antiviral efficacy with BILN 2061, a compet-
itive inhibitor of the HCV NS3 serine protease that now has been
discontinued.6 More recently, new macrocyclic inhibitors were re-
ported with ITMN-191 (phase I),7 TMC435350 (phase II)8 and the
most advanced MK-7009 currently in phase II with proof-of-con-
cept achieved.9 As another class, covalent reversible
a-ketoamide
electrophilic serine trap inhibitors have been reported by our
group10 and others11 to be potent inhibitors of HCV NS3 serine pro-
tease. Recently, we published our work that led to the identifica-
tion of our first generation clinical candidate 1.12 Clinical
candidates Telaprevir (VX-950) and 1 belonging to the
a-ketoa-
mide series established proof of concept and phase III clinical stud-
ies are underway.13 In this manuscript, we report our efforts aimed
at optimizing the overall profile of our first generation inhibitor.
Our goal for a second generation inhibitor was to improve the cel-
lular potency and exposure across species.
Lately, we reported that P4-capped inhibitors could provide
* Corresponding author. Tel.: +1 9087404642; fax: +1 9087407152.
E-mail address: Stephane.Bogen@spcorp.com (S.L. Bogen).
enhanced enzyme and cellular potency.14 Initially, we identified
0968-0896/$ - see front matter Ó 2010 Elsevier Ltd. All rights reserved.
doi:10.1016/j.bmc.2010.01.044

S. L. Bogen et al. / Bioorg. Med. Chem. 18 (2010) 1854–1865
1855
Table 1
a novel series of potent P4 ester derived inhibitors, as exemplified
by compound 2 (Fig. 1), with a spirocyclohexyl group at P4 that
demonstrated 18-fold improvements in cellular potency (EC90
)
but lacked oral exposure in rat (Table 1, compound 1). Derivatiza-
tion of the ester to a ketone moiety followed by modification of the
P4 and P01 capping residues drastically improved rat oral exposure
but resulted in weak cell potency. P1 butynylglycine was identified
as a moiety that, when used in combination with a cyclopropyl ke-
tone group at P4, provided compound 3 (Fig. 1) with excellent bind-
ing and much improved cellular potencies versus 1. Unfortunately,
P1 butynylglycine was not the optimal substitution for HNE/HCV
selectivity (Table 1, compound 3) and the electrophilic ketone moi-
ety at P4 was not a desirable feature for a progression candidate.
Due to the excellent cellular potency observed with compound 2,
we decided to further explore the scope of the 1-substituted-cyclo-
hexyl ureas series. We discovered that incorporation of a sulfon-
amide moiety at P4 and optimization of the P1 residue not only
significantly improved potency and maintained selectivity but also
provided good PK profile in three preclinical species (Table 2, com-
pound 47). Herein, we report our finding that led to the discovery
of new P4 extended ketoamide inhibitors of the HCV NS3 serine
protease with improved potency and DMPK properties.
O
H
N
H
N
N
O
O
O
O
NH
NH
R
Kiꢀ
Compd
R
EC90
HNE/
AUC (lM h)0–6h
Ratd Doge Monkeyf
(nM)b 2HCVc
(nM)a
1
2
3
—
—
—
14
49
4
350
20
55
4400
55
0.1 3.1g 0.3
0
11
0
0.05
20
0.1
—
H
N
h
28
15
300
55
58
82
—
—
—
S
S
O
O
N
29
6
0.6 6.1
0.1
2. Chemistry
O
O
Synthesis of the inhibitors was generally carried out as depicted
in Scheme 1. The gem-dimethylcyclopropylproline P2 core 4, essen-
tial for potency, was used to prepare dipeptide 5 according previ-
ously described protocols.12b Substituted cyclohexyl sulfonamides
of type 6 were converted to either an isocyanate or a 4-nitrophe-
nylcarbamate intermediate before being reacted with amine
N
30
31
9
7
65
70
64
97
1.5 0.5
0.9 0.2
0.1
S
O
O
N
—
S
O
O
O
N
32
8
55
36
0.6 0.2
—
—
S
P2
O
O
P1'
H
N
NH2
N
P3
N
S
O
O
O
33
34
35
36
2.8
8
45
55
—
82
—
0.1 0.2
1.8 6.9
0.3 0.2
O
O
P1
F
O
NH
NH
1 (SCH 503034)
N
3.3
S
O
Ki* = 14 nM
O
O
EC90 = 350 nM
P4
N
7
90
—
—
S
O
O
H
N
NH2
N
O
O
N
O
9
135
—
—
—
S
O
NH
NH
O
O
O
2
Ki* = 49 nM
O
EC90 = 20 nM
N
37
5
65
131
1
7.9
0
S
O
O
O
O
H
H
N
N
38
39
40
6
7
8
100
80
—
—
1.7 0.5
0.8 0.8
0.3 0.3
—
—
—
N
S
N
O
O
O
O
O
NH
NH
N
O
S
O
O
3
Ki* = 4 nM
O
EC90 = 55 nM
N
45
135
S
O
O
(continued on next page)
Figure 1. Profile of 1 (SCH 503034), 2 and 3.

1856
S. L. Bogen et al. / Bioorg. Med. Chem. 18 (2010) 1854–1865
Table 2
Table 1 (continued)
Kiꢀ
Compd
R
EC90
HNE/
AUC (
lM h)0–6h
(nM)b 2HCVc
(nM)a
Ratd Doge Monkeyf
O
H
N
H
N
H
H
H
N
N
41
42
43
44
2
22
4
85
—
—
—
0.6 0.1
—
—
—
—
S
S
O
P1
O
O
O
O
O
O
O
NH
NH
N
—
—
—
—
N
O
S
O
O
N
20
20
340
340
0.1
0.1
S
Kiꢀ
Compd
P1
EC90
HNE/
HCVc
AUC (lM h)0–6h
O
(nM)b
(nM)a
H
Ratd
2.2
Doge
Monkeyf
N
4
S
g
O
O
45
46
15
60
113
959
1.4
—
Kꢀi value represents binding for a single diastereomer at P1 and within twofold
for 95% confidence limit.
HNE/HCV is a ratio of selectivity between human neutrophil elastase (HNE), a
serine protease and HCV serine proteases.
Replicon (genotype 1) EC90 value is within threefold for 95% confidence (single
assay) and within twofold for 95% confidence (multiple assays).
a
b
11
6
105
—
—
4
—
c
d
Rat PO were dosed at 10 mpk (no IV arm). Number of animals used: 2. Vehicle:
47
75
2485
0.9
5.4
PO (0.4%HPMC).
e
Dog PO were dosed at 2 mpk (no IV arm). Number of animals used: 2. Vehicle:
PO (0.4%HPMC).
f
Kꢀi value represents binding for a single diastereomer at P1 and within twofold
Monkey PO were dosed at 10 mpk (no IV arm). Number of animals used: 2.
a
Vehicle: PO (0.4%HPMC).
for 95% confidence limit.
g
Dog PO were dosed at 3 mpk (no IV arm). Number of animals used: 3. Vehicle:
b
HNE/HCV is a ratio of selectivity between human neutrophil elastase (HNE), a
PO (0.4%HPMC).
serine protease and HCV serine proteases.
h
Not determined.
c
Replicon (genotype 1) EC90 value is within threefold for 95% confidence (single
assay) and within twofold for 95% confidence (multiple assays).
d
Rat PO were dosed at 10 mpk (no IV arm). Number of animals used: 2. Vehicle:
hydrochloride 5. Hydrolysis of the resulting methyl ester interme-
diate to carboxylic acid 7 was follwed with HATU mediated cou-
PO (0.4%HPMC).
e
Dog PO were dosed at 2 mpk (no IV arm). Number of animals used: 2. Vehicle:
PO (0.4%HPMC).
pling to P1
a-hydroxy-b-aminoamide intermediates of type 8.
f
Monkey PO were dosed at 10 mpk (no IV arm). Number of animals used: 2.
The resulting secondary hydroxyamide moieties were oxidized
using Dess–Martin conditions to deliver targets 28–47 included
in Tables 1 and 2.15
Vehicle: PO (0.4%HPMC).
g
Not determined.
The sulfonamide capping moieties were prepared according to
two different procedures outlined in Scheme 2 and 3. With the goal
of quickly exploring various sulfonamides, we identified sulfonyl
chloride 12 as a key intermediate. The iodomethyl cyclohexanecar-
boxylic acid methyl ester 10 was efficiently prepared by reacting
the enolate of cyclohexanecarboxylic acid methyl 9 with diiodo-
methane. Displacement of 10 with potassium thioacetate in DMF
afforded sulfonyl intermediate 11 in good yield. Preparation of
12 was challenging. Thus, the use of 4 equiv of water and 3 equiv
of chlorine gas in AcOH were found optimal to suppress over chlo-
rination and deliver exclusively desired sulfonyl chloride 12 in very
high yield. Various sulfonamides of type 13 were accessed upon
treatment of 12 with primary or secondary amines. Hydrolysis of
the resulting methyl ester to carboxylic acid intermediate followed
by a Curtius rearrangement yielded isocyanates 14.16
R2 R4
N
R5
R3
S
O O
a
6
OMe
OMe
N
N
H
b
O
O
HCl.H2N
O
5
4
OH
H
N
8a-d
OH
H2N
R2
R4
N
H
N
H
O
R1
O
N
N
O
R3
S
O O
O
c
7
Chiral acyclic and cyclic sulfonamides were prepared according
Scheme 3, thus (S)-tert-butanesulfinamide was reacted with cyclo-
hexanone 15 in the presence of titanium tetraethoxide to generate
sulfinamide 16. Alkylation of 16 with various lithiated acyclic and
cyclic sulfonamides was used to prepare intermediates 17 as a
mixture of diastereomers. HCl-mediated removal of the chiral aux-
iliary of intermediates 17 and subsequent treatment with either
phosgene or 4-nitrophenylchloroformate led to the corresponding
isocyanates 18 and activated carbamates 19 needed for P4 capping
exploration.
O
H
N
H
N
R2
R4
N
H
H
O
R1
O
N
N
N
O
R3
S
O
O
O
28-47
Scheme 1. Reaction conditions: (a) (i) Boc-t-leucine, EDC, HOOBt; DMF/CH2Cl2,
iPr2NEt, 0 °C; (ii) 4 M HCl; p-dioxane, rt; (b) (i) (R5 = isocyanate) 5, DCM, aq NaHCO3
or (R5 = 4-nitrophenylcarbamate) 5, DCM, DIPEA; (ii) 4, DCM, DIPEA, 0 °C; (iii) LiOH,
THFꢁMeOH/H2O, 0 °C; (c) (i) HATU; DMF/CH2Cl2, iPr2NEt; (ii) Dess–Martin
periodinane.
The P1
a-hydroxy-b-aminocyclopropylamides 8a–d were pre-
pared according the procedures outlined in Scheme 4. Synthesis
of (S)-Homo-cyclopropyl alanine hydroxyamide 8d was initiated

S. L. Bogen et al. / Bioorg. Med. Chem. 18 (2010) 1854–1865
1857
O
O
CO2Me
O
O
CO2Me
CO2Me
I
S
BocN
b
BocN
BocN
a
b
a
O
11
CO2Me
10
9
22
O
21
R2
N
20
Cl
O
CO2Me
c
S
d
R3
S
O
OH
H
N
H
O
O
c
d
N
Boc
24
H
Boc
23
13
12
O
R2
N
N
C
R3
S
e
O
O
O
OH
H
H
N
14
e
N
HCl.H2N
Boc
H
Scheme 2. Reaction conditions: (a) (i) LDA, THF, ꢂ10 °C; (ii) CH2I2, 0 °C to rt, 100%;
(b) KSCOMe, DMF, 15 °C to rt overnight, 81%; (c) AcOH, H2O (4 equiv), Cl2 (3 equiv),
93%; (d) R2R3NH, DCM, DIPEA, 0 °C to rt; (e) (i) KOH, MeOH, 60 °C; (ii) DPPA, Et3N,
PhMe, 110 °C.
R1
O
R1
8a: R1= (S)-Nva
25: R1= (S)-Nva
8b
26: R1= (S)-c-PrAla
: R1= (S)-c-PrAla
27
: R1= (S)-NLeu
8c: R1= (S)-NLeu
O
R2 R4
S
8d: R1= (S)-Homo-c-PrAla
24: R1= (S)-Homo-c-PrAla
O
N
H
N
(S)
N
a
b
R3
S
O
S
O
Scheme 4. Reaction conditions: (a) cyclopropylmethyltriphenylphospho-nium
bromide, KHMDS, THF, ꢂ78 °C, 96%; (b) Tos-NH–NH2, dimethoxyethane, sodium
acetate, H2O, 90 °C, 4 h, 95%; (c) MeOH, TsOH cat, 95%; (d) NaOCl (5%, 1.1 equiv),
LiBr (0.076 equiv), NaHCO3 (1.4 equiv), TEMPO (0.014 equiv), EtOAc, 0 °C; (e) (i)
cyclopropylisonitrile, AcOH, DCM, (2–1 ratio); (ii) K2CO3, MeOH, H2O; (iii) 4 M HCl/
Dioxane, 0 °C to rt.
O
15
16
17
c
R2 R4
d
N
N
R3
S
O
C
O
O
R2 R4
HCV replicon inhibitory activity for the targets synthesized was ob-
tained using previously reported assay.22 To address the issue of
selectivity among serine proteases, inhibitors were assayed against
human neutrophil elastase (HNE), a serine protease with most
structural similarity to HCV NS3 serine protease. The ratio of activ-
ity in these two proteases (HNE/HCV) was used as a measure of the
selectivity. As a general trend, previous compounds had GAPDH
H
N
18
N
O
R3
S
O
O
O
NO2
19
Scheme 3. Reaction conditions: (a) (S)-H2NS(O)tBu, Ti(OEt)4, THF, 60 °C, 76%; (b)
R2R3NSO2CH2R4, n-BuLi, toluene, ꢂ78 °C, 55–60%; (i) 4 M HCl/Dioxane, 0 °C to rt; (ii)
phosgene (20% in toluene), DCM, aq NaHCO3, 0 °C to rt, 1 h; (d) (i) 4 M HCl/dioxane,
0 °C to rt, 100%; (ii) 4-nitrophenylchloroformate, DIPEA, DCM, 0 °C to rt.
CC50 >5 lM when tested in counter screen measuring cellular tox-
icity. Thus, cytotoxicity was never an issue for this class of inhibi-
tors, and GAPDH was not measured for most recent compounds.
We evaluated our initial set of P4 extended inhibitors 28–45 listed
in Table 1 by varying the R2, R3 and R5 moieties. As discussed be-
fore, the P4 was maintained as a spirocyclohexyl residue since we
had previously observed that the use of 1-methyl-cyclohexyl urea
as a P4 capping group in inhibitor 2 improved the replicon activity
by 18-fold compared to 1. tert-Leucine moiety which was previ-
from D-Garner aldehyde.17 Cyclopropylmethyl triphenylphospho-
nium bromide, after treatment with KHMDS, was reacted with
20 to generate 21 in very high yield. Standard hydrogenation reac-
tion for 21 failed to provide the saturated intermediate 22. Sodium
acetate and p-toluenesulfono hydrazide were used to chemoselec-
tively reduce the olefin of 21 without reducing the adjacent cyclo-
propyl ring. p-Toluenesulfonic acid mediated removal of the
acetonide protection of intermediate 22 and subsequent TEMPO-
catalyzed oxidation of 23 with bleach18 led to aldehyde 24 which
was immediately subjected to the Passerini reaction conditions.19
Thus, use of cyclopropylisonitrile and acetic acid in DCM generated
a diastereomeric mixture of acetamides. Hydrolysis of the acetate
moiety using potassium carbonate in MeOH followed by HCl-med-
ously optimized as
a
P3 surrogates and the gem-dim-
ethylcyclopropylproline P2 were used as the substituents of
choice in these positions during that entire study.12b During our
earlier exploratory studies that led to the discovery of 1, we ob-
served that P01 secondary amides, especially allyl amides, when
used in combination with norvaline at P1 provided inhibitors with
very good rat PK profile.12b For the initial set of compound, we
decided to focus on single diastereomer and keep the P1 constant
as norvaline. From our previous experience, we were aware of
the fact that the P1 norvaline was not the optimal substitution
for potency and selectivity over HNE but as a readily available frag-
ment we used it for the initial studies.12b Finally, based on recently
published results from our laboratories,14 we choose to use the P01
cyclopropyl amide capping of compound 3 and maintained it for
the entire study.
iated removal of the Boc protecting group yielded desired a-hydro-
xy-b-aminocyclopropylamides 8d in 47% overall yield. Norvaline
8a, Cyclopropylalanine 8b and Norleucine 8c were prepared in a
similar fashion starting from the corresponding aldehyde 25, 26
and 27 or by following reported procedures.12b,20
3. Discussion
Modeling studies suggested that there was ample room for the
P4 cap to be extended beyond the spirocyclohexyl group. The
Cys159 amino acid residue of the protein backbone in the S4 region
was identified as an opportunity for additional hydrogen bonding
Inhibitors listed in Tables 1 and 2 were tested in continuous as-
say using the NS4A-tethered single chain NS3 serine protease.21

1858
S. L. Bogen et al. / Bioorg. Med. Chem. 18 (2010) 1854–1865
interaction. We envisioned that extended inhibitors having sulfo-
nyl or carbonyl groups at the P4 position could engage in a hydro-
gen bonding with Cys159. Recent results from our laboratories
confirmed our hypothesis.23 In the course of our extensive search
for the optimal functionality to establish the hydrogen bond, we
discovered that secondary methylsulfonamide 28 (Table 1,
to be essential for activity as inhibitor 41 (Kꢀi = 2 nM) was tenfold
more potent than inhibitors 42 (Kꢀi = 22 nM), the correspondent
(S) isomer. However, when compared to dimethylsulfonamide 29
(EC90 = 55 nM), substitution onto the methylene spacer between
the sulfonamide and the spirocyclohexyl groups resulted in lower
cellular potency (Table 1, entry 41, EC90 = 85 nM) and much lower
exposure in dog. Tethering of the methyl group was envisioned to
access a more rigid cyclic core. The (R) diastereomers were
prepared since we had established earlier that this is the desired
stereochemistry requirement. We discovered that the incorpora-
tion of the five-membered cyclic sulfonamide provided inhibitor
43 with more than fourfold improvement in cell potency
(EC90 = 20 nM, HNE/HCV = 340) compared to 41 and good elastase
selectivity. Inhibitor 43 was the first of its class to show such
enhanced activity in the replicon assay. Based on our earlier SAR
finding, we incorporated the cyclopropyl moiety of our best inhib-
itor 34 into the cyclic sulfonamide series. Thus, compound 44 was
prepared and showed excellent cellular potency as well (Table 1,
EC90 = 20 nM). The pharmacokinetic properties of inhibitor 43
and 44 were investigated and the data is listed in Table 1. Unfortu-
nately, both compounds showed poor exposure in rat after oral
administration and efforts in this series were discontinued.
Having established that the cyclopropyl N-methyl sulfonamide
moiety as the optimal substitution for the acyclic sulfonamide ser-
ies, we turned our effort toward improving the elastase selectivity
of inhibitor 34. During our earlier exploratory studies that led to
the discovery of 1, we observed that the P1 norvaline was not the
optimal substitution for HNE/HCV selectivity.12b Cyclopropyl ala-
nine analog 45 and nor-leucine analogs 46 were prepared and pro-
vided improvements in elastase selectivity. However, it was clear
from the data presented in Table 2 that introduction of homocyclo-
propylalanine at P1 had a profound effect on the HNE/HCV selectiv-
ity while maintaining cellular potency of compound 47 (Kꢀi = 6 nM,
EC90 = 75 nM) when compared to inhibitor 34. Furthermore, 47
exhibited not only good oral exposure in rat (10 mpk, AUC
Kꢀ = 15 nM, EC90 = 300 nM), had enzyme and cellular potency sim-
i
ilar to that of 1. The activity demonstrated by compound 28
prompted us to further investigate the SAR of various P4 residues.
Compounds prepared to evaluate this effect are outlined in Table 1.
Dimethylsulfonamide 29 (EC90 = 55 nM) established that tertiary
sulfonamides provided enhanced cellular potency (sixfold
improvement vs 28). The rat, dog and monkey pharmacokinetic
properties of inhibitor 29 were investigated and the data is sum-
marized in Table 1. Although we were glad to see excellent expo-
sure in dog (6.1 lM h), oral area-under-curve (PO AUC) level in
rat and monkey were similar to 1 and needed improvement for a
second generation compound. Modifications of the dimethyl suf-
onamide moiety with larger substituents were explored. Thus,
incorporation of an ethyl, isopropyl and tert-butyl group in sulfon-
amides 30, 31 and 32 resulted in similar enzyme and cellular activ-
ity but lower exposure in dog compared to 29. Fluorinated
sulfonamide 33 was prepared with the aim of improving the phar-
macokinetic profile of compound 32. Unfortunately, while improv-
ing the ezyme potency (Kꢀi = 2.8 nM) and retaining good cellular
potency (EC90 = 45 nM), rat and dog exposure of fluorinated sulfon-
amide 33 was lower compared to 32. Cyclic substituents (Table 1,
entry 34 and 35) were investigated and results obtained with
cyclopropyl sulfonamide 34 were encouraging. Although the po-
tency profile of compound 34 (Table 1, Kꢀ = 8 nM, EC90 = 55 nM)
i
was similar to 29, this cyclopropyl N-methyl sulfonamide capped
inhibitor exhibited for the first time good oral exposure in all three
species with tenfold exposure enhancement in monkey compared
to 1. A compound with larger ring size was prepared but the analog
35, with a cyclobutyl substituent (Table 1, EC90 = 90 nM) was less
potent in the cellular assay and displayed poorer PK in rat and
dog compared to the cyclopropyl counterpart 34. The improved
overall profile demonstrated by compound 34 in comparison to 1
prompted us to further investigate the SAR of this cyclopropyl N-
methyl sulfonamide P4 residue. The bulkier cyclopropylmethyl
(lM h)0–6h = 0.9) and dog (2 mpk, AUC (lM h)0–6h = 4) but in mon-
key as well (10 mpk, AUC ( M h)0–6h = 5.4).
l
To illustrate the interactions of the P4 cap with the protein,
Figure 2 shows compound 47 modeled in the active site of the
NS3/NS4A protease domain. The overall binding mode of the
P1–P4 residues would be as expected predefined by the backbone
hydrogen bonding network between the inhibitor and the protein.
The P4 spirocyclohexyl of compound 47 was found to bind to the
group in inhibitor 36 (Kꢀ = 9 nM, EC90 = 135 nM) was detrimental
i
to the cell activity. We further probed the P4 cyclopropyl N-methyl
sulfonamide series and we discovered that incorporation of small
groups was tolerated. Thus, cyclopropyl N-ethyl sulfonamide 37
was prepared and showed similar potency profile to the cyclopro-
pyl N-methyl sulfonamide analog 34. Moreover, the HNE selectiv-
ity seemed improved for that series with HNE/HCV = 131.
Unfortunately, while maintaining good exposure in rat and dog,
37 completely lacked oral exposure in monkey. Incorporation of
the larger isopropyl group led to inhibitor 38 (Kꢀi = 6 nM,
EC90 = 100 nM) that resulted in loss of cellular activity compared
to 34 (EC90 = 55 nM). Cyclic amines (Table 1, inhibitors 39, 40)
were also studied. Cyclobutylsulfonamide 39 (Table 1, Kꢀi = 7 nM,
EC90 = 80 nM) had a similar potency profile when compared to
the simple dimethylsulfonamide 29 but did not show exposure
in dog after oral administration. Inhibitor 40 bearing a morpholine
sulfonamide moiety with potentially better solubility properties
was also prepared. Unfortunately, although the cellular potency
of compound 40 (Table 1, Kꢀ = 8 nM, EC90 = 45 nM) was improved,
i
no enhancement of oral exposure in rat or dog was observed.
To further probe the P4 region we also envisioned substitution
onto the methylene spacer between the sulfonamide and the spiro-
cyclohexyl groups. Thus, the diastereoselective synthesis of this
class of chiral sulfonamide was initiated. As a direct comparison
with our earlier dimethylsulfonamide lead 29, we prepared both
R- and S- diastereomer 41 and 42. The R stereochemistry seemed
Figure 2. Model of 47 bound to the active site of HCVNS3/NS4A protease domain.
The inhibitor is shown as stick model (yellow carbon) and the protein as surface
(gray carbon). The S1–S4 subsites and the residues that occupy the S4 pocket as
well as Cys 159 are labeled. The hydrogen bond between one of the sulfone oxygens
and the NH of Cys159 is indicated (green dashed line).

S. L. Bogen et al. / Bioorg. Med. Chem. 18 (2010) 1854–1865
1859
S4 subsite, a shallow hydrophobic pocket consisting of residues Arg
5.2.1. (1R,2S,5S)-3-((S)-2-(3-(1-((N-Cyclopropyl-N-methylsulfa-
123, Asp 168, Arg 155, Ala 156 and Val 158. For the P4 cap, one of the
sulfone oxygens was found to make a hydrogen bond with the
backbone NH of Cys159. The cyclopropyl group off the sulfonamide
moiety also makes hydrophobic contacts with the sidechain of
Cys159. The favorable hydrophobic contacts of the P4 cyclopropyl
cap with the side chain of Cys159 and the additional hydrogen bond
with the backbone NH of Cys159 may attribute to the enhancement
in enzyme potency of compound 47 compared with 1.
moyl)methyl)cyclohexyl)ureido)-3,3-dimethylbutanoyl)-6,6-di-
methyl-3-azabicyclo[3.1.0]hexane-2-carboxylic acid (6; R3 = c-Pr,
R2 = Me, R4 = H)
To a 0 °C DMF (50 mL) solution of (1R,2S,5S)-methyl 3-((S)-2-ami-
no-3,3-dimethylbutanoyl)-6,6-dimethyl-3-azabicyclo[3.1.0]hexane-
2-carboxylate hydrochloride 412b (10 mmol, 3.18 g) was added
isocyanate 14 (0.26 M in DCM, 12 mmol, 47 mL) followed by DIPEA
(60 mmol, 10.2 mL). The reaction was warmed-up to rt and left stir-
ring overnight. The reaction mixture was diluted with DCM and
washed twice with HCl (1.0 M) followed by brine. The organic layer
was dried over MgSO4, filtered and concentrated down to yield
5.96 g of (1R,2S,5S)-methyl 3-((S)-2-(3-(1-((N-cyclopropyl-N-meth-
ylsulfamoyl)methyl)cyclohexyl)-ureido)-3,3-dimethylbutanoyl)-6,6-
4. Conclusion
As we moved towards the discovery of a second generation HCV
protease inhibitor, we discovered that P4-capped inhibitors could
provide enhanced enzyme and cellular potency. Initially, we ob-
served that the use of 1-methyl-cyclohexyl urea as a P4 capping
group in inhibitor 2 was well tolerated and could lead to improve-
ment in cellular potency. Based on modeling studies, we envi-
sioned that extended inhibitors having sulfonyl or carbonyl
groups at the P4 position could engage in a hydrogen bonding with
Cys159. We discovered that the use of sulfonamides moieties at P4
provided potent inhibitors with good pharmacokinetics properties.
Derivatization of the sulfonamide via systematic optimization of
the substituents led to the identification of the cyclopropyl methyl
sulfonamide that generated compound 34 with excellent enzyme
potency, improved replicon activity and the best overall exposure
in rat, dog and monkey. Optimization of the P1 norvaline residue
resulted in the identification of homocyclopropylalanine P1 frag-
ment that, when used in combination with cyclopropyl amide P10
capping, provided compound 47 with excellent HNE/HCV selectiv-
ity, much improved cellular potencies over 1 and good oral expo-
sure in three preclinical species.
dimethyl-3-azabicyclo[3.1.0]hexane-2-carboxylate as
a brown
foam that was immediately dissolved in THF (50 mL). To this solu-
tion was added at 0 °C aqueous LiOH (11.5 equiv, 16.2 mL, 1.0 M).
The reaction was warmed-up to rt and left stirring overnight. The
product was then evaporated to dryness and NaOH (1.0 N, 50 mL)
and Et2O (50 mL) were added. The phases were separated and the
aqueous phase was acidified with 6 N HCl to pH of 1.5. The product
was extracted with EtOAc and washed with brine. The organic layer
was dried over MgSO4, filtered and concentrated down to yield 4.8 g
(88% over 2 steps) of (1R,2S,5S)-3-((S)-2-(3-(1-((N-cyclopropyl-N-
methylsulfamoyl)methyl)cyclohexyl)ureido)-3,3-dimethylbutanoyl)-
6,6-dimethyl-3-azabicyclo[3.1.0]hexane-2-carboxylic acid (6; R3 =
c-Pr, R2 = Me, R4 = H). 1H NMR (400 MHz, DMSO-d6) d 6.24 (d,
J = 9.6 Hz, 1H), 6.00 (br s, 1H), 4.18 (d, J = 9.6 Hz, 1H), 4.07 (s, 1H),
3.91 (d, J = 9.6 Hz, 1H), 3.76–3.68 (m, 2H), 3.59–3.54 (m, 1H), 2.68
(s, 3H), 2.32–2.82 (m, 1H), 2.19–2.06 (m, 2H), 1.55–1.35 (m, 8H),
1.36 (d, J = 7.6 Hz, 1H), 1.20 (d, J = 6.4 Hz, 1H), 0.98 (s, 3H), 0.91 (s,
9H), 0.78 (s, 3H), 0.65–0.59 (m, 4H). 13C NMR (100 MHz, DMSO-d6)
d 173.1, 171.2, 157.2, 66.8, 59.2, 56.7, 53.5, 53.3, 47.4, 37.0, 34.9,
34.4, 31.5, 30.3, 27.2, 26.7, 26.2, 25.4, 21.1, 19.1, 12.7, 7.5, 7.4. HRMS
calcd for C26H45N4O6S: 541.3059 (M + H)+. Found: 541.3045.
5. Experimental
5.1. Molecular modeling
5.2.2. (S)-3-Amino-N,5-dicyclopropyl-2-hydroxypentanamide
hydrochloride (7d)
To model compound 47 in the NS3/NS4A protease active site, the
crystal structure of compound 1 bound to NS3/NS4A protease (PDB
ID 2OBO) was used as a template upon which the P1 and P4 side-
chains and terminal caps corresponding to 47 were built. From
the crystal structure, the backbone atoms form a network of hydro-
gen bonds with the protein, therefore predefine the backbone orien-
tation of the compounds. The sidechain atoms was energy
minimized for 500 steps, followed by another 500 steps of minimi-
zation of the whole inhibitor molecule. SYBYL (Tripos, Inc.) molecu-
lar modeling package was used in model building and optimization.
To a 0 °C solution of alcohol 23 (30 g, 131 mmol) in EtOAc
(250 mL) was added LiBr (0.076 equiv, 10 mmol, 870 mg) followed
by NaHCO3 (14 g, 184 mmol) in water (140 mL) and TEMPO
(0.014 equiv, 1.84 mmol, 300 mg). Bleach (5%, 1.1 equiv, 150 mol,
200 mL) was added at a rate of about 10 mL/min .At the end of
addition, TLC analysis indicated complete conversion. 250 mL of a
ꢄ1 M Na2S2O3 solution was added and stirring was maintained
for 10 min. Layers were separated and EtOAc layer was washed
with NaHCO3 then brine. Organic layer (ꢄ500 mL of EtOAc) was
dried over MgSO4, filtered and processed directly to the next step
without further isolation. To a 0 °C solution of crude aldehyde 24
(131 mmol) in EtOAc (ꢄ500 mL) was added acetic acid (1.2 equiv,
157 mmol, 9 mL) followed by cyclopropylisonitrile (1.05 equiv,
138 mmol, 11.5 mL). The mixture was stirred at to rt for 18 h then
concentrated to dryness to provide (S)-3-(tert-butoxycarbonylami-
5.2. General
NMR spectra were recorded at 300, 400 or 500 MHz for 1H and at
75, 100 or 125 MHz for 13C on a Bruker or Varian spectrometer with
CDCl3 or DMSO-d6 as solvent. The chemical shifts are given in ppm,
referenced to the internal TMS or deuterated solvent signal.
General experimental procedures were described in earlier pub-
lications12b for the synthesis of P2 core, peptide coupling, Boc
group deprotection, hydrolysis of ester to carboxylic acid and
Dess–Martin periodinane oxidation.
Purity of target compounds were determined using LC–MS anal-
ysis. LC/MS analyses were performed using an Applied Biosystems
API-150 mass spectrometer and Shimadzu SCL-10A LC system. Col-
umn: Phenomenex Gemini C18, 5 micron, 50 mm ꢃ 4.6 mm ID,
gradient: from 90% water, 10% CH3CN, 0.05%TFA, 5 min to 5%
water, 95% CH3CN, 0.05% TFA in 5 min, UV detection: 254 nm. All
targets compounds were >95% pure.
no)-5-cyclopropyl-1-(cyclopropylamino)-1-oxopentan-2-yl
ace-
tate as
a
(1/0.8) mixture of two diastereomers. 1H NMR
(400 MHz, DMSO-d6) d 8.07 and 7.95 (d, J = 3.6 Hz, 1H), 6.74 and
6.54 (d, J = 9.2 Hz, 1H), 4.97 and 4.74 (d, J = 4.8 Hz, 1H), 3.95–3.85
(m, 1H), 2.73–2.59 (m, 1H), 2.13 and 2.10 (s, 3H), 1.52–1.35 (m,
11H), 1.27–1.13 (m, 2H), 0.69–0.61 (m, 3H), 0.47–0.37 (m, 4H),
0.03–(ꢂ)0.02 (m, 2H). MS (ESI) 377[(M+Na)+, 10], 355 (20), 299
(30), 237 (100). HRMS calcd for C18H31N2O5: 355.2233 (M+H)+.
Found: 355.2223. To a 1L flask containing (S)-3-(tert-butoxycar-
bonylamino)-5-cyclopropyl-1-(cyclopropylamino)-1-oxopentan-
2-yl acetate (131 mmol) was added MeOH/H2O (300 mL each) and
K2CO3 (327 mol, 45 g). Reaction was stirred at rt for 2 h. TLC

1860
S. L. Bogen et al. / Bioorg. Med. Chem. 18 (2010) 1854–1865
analysis (60/40/DCM/EtOAc) indicated complete conversion. The
reaction mixture was concentrated under vacuum to remove
methanol then the aquous solution was extracted with EtOAc
(200 mL). EtOAc layer was washed with HCl (1 N), then brine and
was dried over MgSO4, filtered and concentrated down to yield
(S)-tert-butyl 5-cyclopropyl-1-(cyclopropylamino)-2-hydroxy-1-
oxopentan-3-ylcarbamate as a (1/0.8) mixture of two diastereo-
mers (35 g, 77% over three steps). 1H NMR (400 MHz, DMSO-d6) d
7.45 and 7.69 (br s, 1H), 6.37 and 6.01 (d, J = 8.8 Hz, 1H), 5.49
and 5.32 (d, J = 6.0 Hz, 1H), 3.82–3.75 (m, 1H), 2.70–2.54 (m, 1H),
1.55–1.35 (m, 2H), 1.33 (br s, 9H), 1.28–1.08 (m, 2H), 0.65–0.50
(m, 3H), 0.44–0.42 (m, 2H), 0.35–0.29 (m, 2H), 0.04–(ꢂ)0.07 (m,
2H). 13C NMR (100 MHz, DMSO-d6) d 173.9, 173.5, 155.6, 155.5,
77.9, 74.0, 72.9, 53.2, 53.1, 31.7, 31.2, 31.1, 28.7, 28.6, 22.5, 22.4,
11.0, 6.1, 6.0, 5.0, 4.9, 4.6, 4.4 MS (ESI) 335[(M+Na)+, 10], 313
(20), 213 (100). HRMS calcd for C18H29N2O4: 313.2127 (M+H)+.
Found: 313.2123. To (S)-tert-butyl 5-cyclopropyl-1-(cyclopropyla-
mino)-2-hydroxy-1-oxopentan-3-ylcarbamate (30 g) was added
HCl dioxane (4.0 N, 10 mL per g, 300 mL) and the reaction was stir-
red at high speed. After 15 min, TLC analysis indicated complete
conversion. Et2O (1 L) was added and stirring was maintained for
10 min. The resulting homogenous slurry was filtered off and dried
under vacuum to provide (S)-3-amino-N,5-dicyclopropyl-2-
hydroxypentanamide hydrochloride 7d as a (1/0.8) mixture of
two diastereomers (24.5 g, 100%). 1H NMR (400 MHz, DMSO-d6) d
8.15 and 8.09 (d, J = 4.4 Hz, 1H), 8.03–8.01 and 7.89–7.80 (m,
2H), 6.39 and 6.27 (br s, 1H), 4.16 and 3.97 (br s, 1H), 2.73–2.58
(m, 1H), 1.75–1.43 (m, 2H), 1.28–1.12 (m, 2H), 0.64–0.57 (m,
3H), 0.53–0.46 (m, 2H), 0.39–0.35 (m, 2H), 0.02–(ꢂ)0.05 (m, 2H).
13C NMR (100 MHz, DMSO-d6) d 172.7, 172.3, 71.1, 70.0, 66.8,
53.3, 53.1, 30.2, 30.1, 29.4, 27.8, 22.7, 22.6, 11.0, 10.9, 6.0, 5.9,
5.8, 5.7, 4.8, 4.7, 4.6, 4.5. MS (ESI) 335[(M+Na)+, 10], 313 (20),
213 (100). HRMS calcd for C11H21N2O2: 213.16030 (M+H)+. Found:
213.1606.
5.2.5. 1-Chlorosulfonylmethyl-cyclohexanecarboxylic acid
methyl ester (12)
To a stirred solution of thioester 11 (53 mmol, 12.23 g) in acetic
acid (55 mL) was added water (212 mmol, 3.8 g). Then, Chlorine
gas (11.3 g, 159 mmol) was bubbled lightly through for about
15–20 min. The internal temp rose to 55 °C and the reaction was
cooled down. TLC analysis indicated complete conversion to a
more polar material. Reaction was diluted in DCM, washed with
water (twice), then NaOH (0.5 N) and brine. DCM layer was dried
over MgSO4, filtered and concentrated down to yield 1-chlorosulfo-
nylmethyl-cyclohexanecarboxylic acid methyl ester 12 obtained as
a light yellow oil (12 g, 90% yield) that was used without further
purification. 1H NMR (400 MHz, CDCl3) d 4.16 (s, 2H), 3.76 (s,
3H), 2.16–2.13 (m, 2H), 1.67–1.10 (m, 8H); MS (ESI)
253[(M+Na)+, 100].
5.2.6. 1-[(Cyclopropyl-methyl-sulfamoyl)-methyl]-cyclohexane-
carboxylic acid methyl ester (13; R3 = c-Pr, R2 = Me)
To a rt solution of DCM (10 mL) containing sulfonyl chloride 12
(4 mmol, 1 g) was added cyclopropyl amine (1.5 equiv, 6 mmol,
0.36 g) followed by Et3N (2 mL). After 5 h, reaction was poured into
EtOAc and washed with NaHCO3, HCl 1.0 N and brine. Organic layer
was dried over MgSO4, filtered and concentrated down to yield
methyl 1-(N-cyclopropylsulfamoylmethyl)cyclohexanecarboxylate
intermediate (1.28 g, 99%). 1H NMR (400 MHz, CDCl3) d 4.68–4.65
(m, 1H), 3.76 (s, 3H), 3.41 (s, 2H), 2.56–2.54 (m, 1H), 2.16–2.13
(m, 2H), 1.67–1.10 (m, 8H), 0.73–0.71 (m, 4H). MS (ESI)
298[(M+Na)+, 100]. To a 0 °C solution of methyl 1-(N-cyclo-
propylsulfamoylmethyl)cyclohexanecarboxylate (4 mmol) in DMF
(10 mL) was added Cs2CO3 (1.5 equiv, 6 mmol, 2 g) followed by
MeI (1.8 equiv, 7.2 mmol, 0.45 mL). Reaction was stirred overnight
then diluted with EtOAc, washed with water (2 ꢃ 50 mL), NH4Cl
and brine. Organic layer was dried over MgSO4, filtered and con-
centrated down to 1-[(cyclopropyl-methyl-sulfamoyl)-methyl]-
cyclohexanecarboxylic acid methyl ester 13 obtained as a light
yellow oil (1.15 g, 100%). 1H NMR (400 MHz, CDCl3) d 3.60 (s,
3H), 3.37 (s, 2H), 2.40–2.38 (m, 1H), 1.97–1.92 (m, 2H), 1.58–1.30
(m, 8H), 0.66–0.64 (m, 4H). MS (ESI) 312[(M+Na)+, 100].
5.2.3. 1-Iodomethyl-cyclohexanecarboxylic acid methyl ester (10)
To a ꢂ78 °C of freshly prepared LDA solution (120 mmol,
75 mL) was added a THF solution (50 mL) of cyclohexane carbox-
ylic acid methyl ester 1 (15.57 g, 109 mmol). After 1 h, diiodo-
methane (109 mmol, 8.78 mL) was added while keeping the
internal temperature below 10 °C. After addition, the reaction
was warmed to rt and stirred overnight. After a total of 18 h,
the reaction was quenched with a saturated NH4Cl solution and
extracted with EtOAc. The organic layer was washed with brine,
dried over MgSO4, filtered and concentrated down to provide 1-
Iodomethyl-cyclohexanecarboxylic acid methyl ester 10 (35 g,
100%) that was used without further purification. 1H NMR
(400 MHz, CDCl3) d 3.72 (s, 3H), 3.31 (s, 2H), 2.14–2.10 (m, 2H),
1.59–1.32 (m, 8H).
5.2.7. N-Cyclopropyl-C-(1-isocyanato-cyclohexyl)-N-methyl-
methanesulfonamide (14; R3 = c-Pr, R2 = Me)
To a rt solution of MeOH (30 mL) containing ester 13 (R3 = c-Pr,
R2 = Me; 4 mmol, 1.1 g) was added aquous KOH (17.6 mL,
61.7 mmol) and the reaction was brought to 55 °C for 18 h. Volatile
were removed under vacuum and residue was acidified to Ph 4
with HCl 1.0 N. Reaction was diluted with EtOAc and washed with
water (2 ꢃ 20 mL) and brine. Organic layer was dried over MgSO4,
filtered and concentrated down to give 1-[(cyclopropyl-methyl-
sulfamoyl)-methyl]-cyclohexanecarboxylic acid (1.09 g, 96%). To
the crude acid (3.96 mmol, 1.09 g) in toluene (15 mL) was added
DPPA (0.85 mL, 3.96 mmol) followed by Et3N (0.56 mL,
3.96 mmol). The reaction was stirred at rt for 10 min then refluxed
for 2 h. Reaction was cooled down to rt and diluted with DCM
(50 mL). The organic layer was washed with NaHCO3, brine and
dried over MgSO4. The volatile were removed and the residue
was diluted with DCM (15 mL) to give N-cyclopropyl-C-(1-isocya-
nato-cyclohexyl)-N-methyl-methanesulfonamide 14 that was used
as a 0.26 M solution in DCM.
5.2.4. 1-Acetylsulfanylmethyl-cyclohexanecarboxylic acid
methyl ester (11)
To 0 °C solution of crude 10 (109 mmol) in DMF (90 ml) was
added Potassium Thioacetate (1.2 equiv, 131 mmol, 15 g) while
maintaining the temperature below 30 °C. The reaction was stirred
for 18 h at rt then cooled to 10 °C. Water (160 mL) was added and
the reaction mixture was extracted with EtOAc. The organic layer
was washed with saturated NaHCO3 then brine. The organic layer
was dried over MgSO4, filtered and concentrated down to a dark
oil. SiO2 column purification (Biotage, 75+M) using 1% to 5% EtOAc
in Hexanes provided 1-acetylsulfanylmethyl-cyclohexanecarbox-
ylic acid methyl ester 11 (43 g, 81% yield over two steps). 1H
NMR (400 MHz, CDCl3) d 3.67 (s, 3H), 3.14 (s, 2H), 2.32 (s, 3H),
2.05–2.01 (m, 2H), 1.60–1.29 (m, 8H). MS (ESI) 304[(M+Na)+, 5],
210 (100).
5.2.8. 2-Methyl-N-[1-(2-methyl-1,1-dioxido-5(R)-isothiazo-
lidinyl]cyclohexyl)-2-propane-(S)-sulfinamide (16, R3 = Me,
R2 = R1 = -CH2)
n-Butyllithium (1.3 equiv, 6.6 mL of a 2.5 M soln in hexanes)
was added dropwise to a cooled (ꢂ78 °C) solution of N-methyl
sultam 16 (1.35 equiv, 2.32 g) in 100 mL of dry THF under anhy-
drous atomosphere. The mixture was stirred for 30 min at that

S. L. Bogen et al. / Bioorg. Med. Chem. 18 (2010) 1854–1865
1861
temperature and then transferred via cannula to a solution of sul-
finyl imine (2.56 g) in 100 mL of dry THF at ꢂ78 °C. After addition
was completed, the reaction mixture was stirred for 30 min. The
reaction was quenched at ꢂ78 °C by addition of 20 mL of aqueous
saturated ammonium chloride solution. The mixture was allowed
to reach room temperature and then partitioned between ethyl
acetate (200 mL) and aqueous saturated sodium bicarbonate solu-
tion (50 mL). The aqueous layer was back extracted with ethyl ace-
tate (2 ꢃ 150 mL). The combined organic layers were washed with
brine (80 mL), dried over magnesium sulfate, filtered and concen-
trated. The residue was chromatographed on silica gel (gradient:
dichloromethane/hexanes; 1:1 to 30% acetone in dicloromethane/
hexanes; 1:1) to afford the R,S-isomer 17 (660 mg; 15.4%). 1H
NMR (CDCl3; 500 MHz) d 4.87 (1H, s), 3.75 (1H, J = 9.4 Hz, t), 3.12
(1H, ddd, J = 3.5 & 8.2 & 9.5 Hz), 3.04 (1H, m), 2.65 (3H, s), 2.27
(2H, m), 2.19 (1H, J = 3.5 & 7.3 & 9.1 & 12.6 Hz, dddd), 2.09 (1H,
J = 3.8 & 10.1 & 13.6 Hz, ddd), 2.02 (1H, J = 3.8 & 10.1 & 13.9 Hz,
ddd), 1.73 (2H, m), 1.61 (1H, m), 1.54 (2H, m), 1.37 (2H, m), 1.23
(9H, s). 13C NMR (CDCl3, 125 MHz): d 61.5, 58.4, 56.2, 46.6, 36.0,
32.6, 30.4, 24.8, 22.9, 22.0, 21.5, 20.3. LRMS (ESI) calcd for
C14H29N2O3S2 [M+H]+: 337.16, found 336.97.
and 4.00 (dd, J = 8.9 & 6.0 Hz, 1H), 3.73–3.70 (m, 1H), 1.59–1.45
(m, 16 H), 0.80–0.68 (m, 2H), 0.42–0.28 (m, 2H). MS (ESI)
290[(M+Na)+, 5], 212 (70), 168 (30).
5.2.11. (S)-tert-Butyl 4-(2-cyclopropylethyl)-2,2-dimethyloxazo-
lidine-3-carboxylate (22)
To a solution of 21 (22.5 mmol, 6 g) and p-toluenesulfono
hydrazide (225 mmol, 42 g) in 200 mL of dimethoxyethane
warmed to reflux was added dropwise a solution of sodium acetate
(375 mmol, 52.5 g) in water (300 mL) over 4 h. After the addition,
reaction was cooled down to rt and poured into 200 mL of water
and extracted twice with EtOAc. The combined organic layers were
washed with brine, dried over MgSO4, filtered and concentrated
down to afford (S)-tert-butyl 4-(2-cyclopropylethyl)-2,2-dimethyl-
oxazolidine-3-carboxylate 22 obtained as a light yellow oil. 1H
NMR (400 MHz, CDCl3) d 3.92–3.80 (m, 2H), 3.72 (d, J = 7.60 Hz,
1H), 1.91–1.60 (m, 2H), 1.59 (s, 3H), 1.54 (s, 3H), 1.48 (s, 9H),
1.25–1.15 (m, 2 H), 0.67–0.65 (m, 1H), 0.42–0.40 (m, 2H), 0.01–
0.00 (m, 2H). MS (ESI) 292[(M+Na)+, 20], 214 (40), 170 (100).
5.2.12. (S)-tert-Butyl 4-cyclopropyl-1-hydroxybutan-2-ylcarba-
mate (23)
5.2.9. 5(R)-(1-Isocyanatocyclohexyl)-2-methylisothiazolidine 1,1-
dioxide (18, R3 = Me, R2 = R1 = -CH2)
To a stirred solution of acetonide 22 (6 g, 22 mmol) in MeOH
(120 mL) was added 1 mol% of TsOH (2.2 mmol, 418 mg). After
30 min, TLC analysis indicated completion. Reaction was diluted
with EtOAc and washed with water, NaHCO3 and brine. Organic
layer was dried over MgSO4, filtered and concentrated down to a
viscous oil. The crude product was purified on Biotage (40+M, 10
to 40% EtOAc in DCM) to provide (S)-tert-butyl 4-cyclopropyl-1-
hydroxybutan-2-ylcarbamate 23 (4.84 g, 96%).1H NMR (400 MHz,
CDCl3) d 4.58 (br s, 1H), 3.69–3.67 (m, 2H), 3.54–3.52 (m, 1H),
1.65–1.49 (m, 2H), 1.45 (s, 9H), 1.30–1.15 (m, 2 H), 0.68–0.65 (m,
1H), 0.45–0.42 (m, 2H), 0.07–0.00 (m, 2H). MS (ESI) 252[(M+Na)+,
70], 174 (30), 130 (100).
The R,S-sulfinamide 16 (R3 = Me, R2 = R1 = –CH2; 640 mg,
1.901 mmol) was dissolved in 40 mL of methanol and treated with
10 mL of 4 M HCl solution in dioxane. The mixture was stirred for
about 30 min until all the starting material had been consumed as
determined by TLC (40% acetone in hexanes). The mixture was evap-
orated to dryness. Dichloromethane was added (10 mL) to make a
cloudy solution. Upon addition of 80 mL of ether a white precipi-
tated formed. The mixture was placed in a cooling bath (0 °C) for
15 min and then the solids were recovered by filtration to afford
1-(2-methyl-1,1-dioxido-5(R)-isothiazolidinyl)cyclohexanamine
hydrochloride (510 mg, 99%) as a white powder. LRMS (ESI) calcd for
C10H21N2O2S [M+H]+: 233.13, found 232.95. A solution of amine
hydrochloride (510 mg, 1.897 mmol) in 40 mL of dichloromethane
was treated with 20 mL of aqueous saturated sodium bicarbonate
solution and stirred vigorously for 10 min at 0 °C. Stirring was
stopped and layers were allowed to separate. Phosgene (10 mL of
20% soln in toluene) was added through a needle to the organic layer
(lower layer) in one portion. The mixture was vigorously stirred
immediately after addition for 20 min at 0 °C and further stirred at
room temp for 3 h. The mixture was diluted with 100 mL of dichlo-
romethaneand layers were separated. The organic layer was washed
with 50 mL of cold aqueous saturated sodium bicarbonate solution
and dried over magnesium sulfate. The organic layer was filtered
and diluted with 15 mL of toluene. The resulting solution was con-
centrated under reduced pressure and the product was used as a
0.126 M solution in toluene.
5.2.13. (1R,5S)-N-[1(S)-[2-(Cyclopropylamino)-1,2-dioxoethyl]-
butyl]-3-[3,3-dimethyl-2(S)-[[[[1-[[(methylamino)sulfonyl]-
methyl]cyclohexyl]amino]carbonyl]amino]-1-oxobutyl]-6,6-
dimethyl-3-azabicyclo[3.1.0]hexane-2(S)-carboxamide (28)
1H NMR (400 MHz, DMSO-d6) d 8.72 (d, J = 4.7 Hz, 1H), 8.38 (d,
J = 7.0 Hz, 1H), 6.68 (d, J = 4.7 Hz, 1H), 6.22 (d, J = 9.4 Hz, 1H),
5.96(s, 1H), 5.00–4.91 (m, 1H), 4.29 (s, 1H), 4.16 (d, J = 10.9 Hz,
2H), 3.91 (d, J = 10.9 Hz, 1H), 3.79–3.70 (m, 1H), 3.56 (d,
J = 14.1 Hz, 1H), 3.30 (d, J = 14.8 Hz, 1H), 2.79–2.69 (m, 1H),
2.51(s, 3H), 2.17 (d, J = 11.7 Hz, 1H), 2.07 (d, J = 12.5 Hz, 1H),
1.75–1.13 (m, 13H), 0.99 (s, 3H), 0.98–0.96 (m,1H), 0.89–0.75 (m,
14H), 0.66–0.62 (m, 2H), 0.59–0.55 (m, 2H). 13C NMR (100 MHz,
DMSO-d6) d 197.1, 171.1, 170.4, 161.9, 156.8, 67.3, 58.9, 56.5,
53.4, 52.7, 38.0, 34.3, 34.2, 33.9, 33.5, 31.6, 28.6, 28.3, 26.2, 26.1,
22.4, 22.3, 20.5, 18.7, 18.4, 13.8, 13.4, 12.4, 10.7, 5.3 ppm. HRMS
(ESI) calcd for C37H60N6O7S [M+H]+: 667.3866, found 667.3865.
5.2.10. (S)-tert-Butyl 4-(2-cyclopropylvinyl)-2,2-dimethyloxazo-
lidine-3-carboxylate (21)
5.2.14. (1R,5S)-N-[1(S)-[2-(Cyclopropylamino)-1,2-dioxoethyll]-
butyl]-3-[2(S)-[[[[1-[[(dimethylamino)sulfonyl]methyl]cyclo-
hexyl]amino]carbonyl]amino]-3,3-dimethyl-1-oxobutyl]-6,6-
dimethyl-3-azabicyclo[3.1.0]hexane-2(S)-carboxamide (29)
1H NMR (400 MHz, DMSO-d6) d 8.73 (d, J = 5.5 Hz, 1H), 8.36 (d,
J = 7.0 Hz, 1H), 6.62 (d, J = 9.4 Hz, 1H), 5.99 (s, 1H), 4.94–4.91 (m,
1H), 4.27 (s, 1H), 4.16 (d, J = 9.4 Hz, 1H), 3.81 (d, J = 10.2 Hz, 1H),
3.73–3.69 (m, 1H), 3.56 (d, J = 14.1 Hz, 1H), 3.27 (d, J = 14.1 Hz,
1H), 2.75–2.69 (m, 1H), 2.65 (s, 6H), 2.16 (d, J = 10.2 Hz, 1H), 2.07
(d, J = 10.2 Hz, 1H), 1.70–1.65 (m, 1H), 1.49–1.27 (m, 14H), 0.98
(s, 3H), 0.87 (br s, 9H), 0.86–0.83 (m, 1H), 0.803 (s, 3H), 0.80–
0.76 (m, 1H), 0.64–0.62 (m, 2H), 0.56–0.53 (m, 2H). 13C NMR
(100 MHz, DMSO-d6) d 197.6, 171.6, 170.9, 162.4, 157.3, 61.5,
59.0, 56.4, 53.4, 52.6, 47.4, 36.8, 34.3, 33.8, 31.6, 30.7, 26.9, 26.2,
To a ꢂ78 °C solution of Cyclopropylmethyl triphenylphospho-
nium bromide (1.5 equiv, 40 mmol, 15.9 g) in THF (180 mL) was
added KHMDS (1.4 equiv, 36.7 mmol, 73.4 mL). The resulting or-
ange solution was warmed-up to rt for 1 h then cooled down to
ꢂ78 °C. To the above solution was added a solution of D-Gardner
aldehyde 20 (1 equiv, 26.2 mmol, 6 g) in THF (20 mL). After reac-
tion was completed by TLC, methanol (200 mL) was added at
ꢂ78 °C and the reaction was gradually warmed-up to rt over 1 h.
Reaction was diluted with EtOAc then washed with water and
brine. Organic layer was dried over MgSO4, filtered and concen-
trated down. Ph3PO was filtered trough a pad of celite and the fil-
trate was concentrated to dryness to provide 7.2 g of 21.1H NMR
(400 MHz, CDCl3) d 5.51–5.30 (m, 1H), 5.15–4.70 (m, 2H), 4.10

1862
S. L. Bogen et al. / Bioorg. Med. Chem. 18 (2010) 1854–1865
m26.0, 24.9, 22.6, 22.4, 20.5, 19.1, 18.7, 18.4, 13.4, 12.5, 5.4, 5.3.
HRMS (ESI) calcd for C33H56N6O7S [M+H]+: 681.4010, found
681.4012.
1H), 4.50 (s, 1H), 4.40 (s, 1H), 4.30 (s, 1H), 4.19 (d, J = 9.8 Hz, 1H),
3.89 (d, J = 10.4 Hz, 1H), 3.73–3.68 (m, 2H), 2.77 (s, 3H), 2.16–
2.14 (m, 1H), 2.06–2.04 (m, 1H), 1.72–1.67 (m, 1H), 1.51–1.36
(m, 10H), 1.31 (s, 9H), 1.15–1.10 (m, 1H), 0.99 (s, 3H), 0.89–0.83
(m, 13H), 0.81 (s, 3H), 0.66–0.64 (m, 2H), 0.58–0.56 (m, 2H). 13C
NMR (125 MHz, DMSO-d6, C–F coupled spectrum) d 197.1, 171.0,
170.3, 161.9, 156.7, 88.6, 87.2, 59.6, 59.5, 58.9, 58.6, 56.3, 53.4,
52.9, 47.3, 34.4, 34.3, 34.2, 33.9, 32.1, 31.5, 30.6, 26.8, 26.1, 26.0,
24.9, 23.3, 23.2, 23.1, 22.3, 20.5, 20.5, 18.6, 18.3, 13.3, 12.4, 5.3,
5.2. HRMS (ESI) calcd for C33H56N6O7S [M+H]+: 741.4398, found
723.4393.
5.2.15. (1R,5S)-N-[1(S)-[2-(Cyclopropylamino)-1,2-dioxoethyl,]-
butyl]-3-[2(S)-[[[[1-[[[ethyl(methyl)amino]sulfonyl]methyl]-
cyclohexyl]amino]carbonyl]amino]-3,3-dimethyl-1-oxobutyl]-
6,6-dimethyl-3-azabicyclo[3.1.0]hexane-2(S)-carboxamide (30)
1H NMR (500 MHz, DMSO-d6) d 8.73 (d, J = 5.0 Hz, 1H), 8.36 (d,
J = 6.6 Hz, 1H), 6.21 (d, J = 9.8 Hz, 1H), 5.99 (s, 1H), 4.97–4.93 (m,
1H), 4.28 (s, 1H), 4.17 (d, J = 10.0 Hz, 1H), 3.89 (d, J = 10.4 Hz,
1H), 3.73 (dd, J = 5.4 Hz, 1H), 3.58 (d, J = 14.1 Hz, 1H), 3.27 (d,
J = 14.1 Hz, 1H), 3.04 (dd, J = 6.9 & 14.1 Hz, 2H), 2.77–2.71 (m,
1H), 2.67 (s, 3H), 2.16 (d, J = 11.9 Hz, 1H), 2.07 (d, J = 11.9 Hz,
1H), 1.71–1.66 (m, 1H), 1.51–1.29 (m, 12H), 1.06 (t, J = 6.9 Hz,
3H), 0.99 (s, 3H), 0.89 (s, 9H), 0.89–0.84 (m, 4H), 0.81 (s, 3H),
0.67–0.63 (m, 2H), 0.58–0.55 (m, 2H). 13C NMR (125 MHz,
DMSO-d6) d 197.1, 170.3, 170.0, 161.9, 156.7, 58.9, 56.3, 54.3,
53.4, 52.6, 47.3, 43.8, 34.3, 33.9, 33.2, 31.6, 30.6, 26.8, 26.1, 26.0,
24.9, 22.4, 20.5, 18.6, 16.4, 13.4, 13.3, 12.4, 5.3, 5.2. HRMS (ESI)
calcd for C33H56N6O7S [M+H]+: 695.4179, found 695.4178.
5.2.19. (1R,5S)-N-[1(S)-[2-(Cyclopropylamino)-1,2-dioxoethyl]-
butyl]-3-[2(S)-[[[[1-[[[cyclopropyl(methyl)amino]sulfonyl]-
methyl]cyclohexyl]amino]carbonyl]amino]-3,3-dimethyl-1-
oxobutyl]-6,6-dimethyl-3-azabicyclo[3.1.0]hexane-2(S)-
carboxamide (34)
1H NMR (400 MHz, DMSO-d6) d 8.73 (d, J = 5.4 Hz, 1H), 8.36 (d,
J = 7.0 Hz, 1H), 6.20 (d, J = 10.2 Hz, 1H), 6.01 (s, 1H), 4.96–4.92 (m,
1H), 4.26 (s, 1H), 4.16 (d, J = 10.9 Hz, 1H), 3.89 (d, J = 10.9 Hz, 1H),
3.73–3.67 (m, 2H), 3.36–3.30 (m, 1H), 2.75–2.70 (m, 1H), 2.68 (s,
3H), 2.32–2.28 (m, 1H), 2.21 (d, J = 11.7 Hz, 1H), 2.08 (d,
J = 11.7 Hz, 1H), 1.73–1.63 (m, 1H), 1.53–1.23 (m, 12H), 1.15–
1.10 (m, 1H), 0.98 (s, 3H), 0.87–0.81 (m, 12H), 0.80 (s, 3H), 0.65–
0.59 (m, 6H), 0.58–0.53 (m, 2H). 13C NMR (100 MHz, DMSO-d6) d
197.6, 171.6, 170.8, 162.4, 157.3, 61.4, 58.5, 56.9, 53.9, 53.3, 46.7,
37.0, 35.0, 34.9, 34.8, 32.1, 31.5, 29.7, 27.9, 27.3, 26.7, 26.6, 25.4,
22.9, 21.0, 19.2, 18.9, 13.9, 12.9, 7.5, 7.4, 5.9, 5.8. HRMS (ESI) calcd
for C33H56N6O7S [M+H]+: 707.4166, found 707.4168.
5.2.16. (1R,5S)-N-[1(S)-[2-(Cyclopropylamino)-1,2-dioxoethyl]-
butyl]-3-[3,3-dimethyl-2(S)-[[[[1-[[[methyl(1-me5thylethyl)-
amino]sulfonyl]methyl]cyclohexyl]amino]carbonyl]amino]-1-
oxobutyl]-6,6-dimethyl-3-azabicyclo[3.1.0]hexane-2(S)-
carboxamide (31)
1H NMR (500 MHz, DMSO-d6) d 8.73 (d, J = 5.0 Hz, 1H), 8.36 (d,
J = 6.9 Hz, 1H), 6.19 (d, J = 9.8 Hz, 1H), 5.97 (s, 1H), 4.97–4.93 (m,
1H), 4.28 (s, 1H), 4.18 (d, J = 10.0 Hz, 1H), 3.95–3.86 (m, 2H),
3.73–3.71 (m, 1H), 3.58 (d, J = 13.9 Hz, 1H), 3.25 (d, J = 14.2 Hz,
1H), 2.77–2.71 (m, 1H), 2.58 (s, 3H), 2.16 (d, J = 12.3 Hz, 1H), 2.06
(d, J = 11.3 Hz, 1H), 1.71–1.66 (m, 1H), 1.52–1.29 (m, 11H), 1.07
(d, J = 6.6 Hz, 6H), 0.99 (s, 3H), 0.89 (s, 9H), 0.89–0.84 (m, 5H),
0.81 (s, 3H), 0.66–0.64 (m, 2H), 0.58–0.56 (m, 2H). 13C NMR
(125 MHz, DMSO-d6) d 197.1, 170.3, 170.0, 161.9, 156.7, 58.9,
56.3, 53.4, 52.8, 47.5, 47.3, 34.3, 34.2, 33.8, 31.6, 30.6, 26.8, 26.6,
26.1, 26.0, 24.9, 22.4, 20.5, 20.4, 19.9, 19.8,18.7, 18.3, 13.4, 12.4,
5.3, 5.2. HRMS (ESI) calcd for C35H60N6O7S [M+H]+: 709.4282,
found 709.4294.
5.2.20. (1R,5S)-3-[2(S)-[[[[1-[[[Cyclobutyl(methyl)amino]sulfo-
nyl]methyl]cyclohexyl]amino] carbonyl]amino]-3,3-dimethyl-
1-oxobutyl]-N-[1(S)-[2-(cyclopropylamino)-1,2-dioxoethyl]-
butyl]-6,6-dimethyl-3-azabicyclo[3.1.0]hexane-2(S)-
carboxamide (35)
1H NMR (400 MHz, DMSO-d6) d 8.73 (d, J = 5.0 Hz, 1H), 8.37 (d,
J = 6.9 Hz, 1H), 6.20 (d, J = 9.8 Hz, 1H), 5.99 (s, 1H), 4.98–4.94 (m,
1H), 4.30 (s, 1H), 4.20 (d, J = 9.8 Hz, 1H), 4.11–4.07 (m, 1H), 3.89
(d, J = 10.0 Hz, 1H), 3.76–3.73 (m, 1H), 3.52 (d, J = 13.6 Hz, 1H),
3.19 (d, J = 13.9 Hz, 1H), 2.78–2.73 (m, 1H), 2.67 (s, 3H), 2.17–
2.13 (m, 3H), 2.04–1.95 (m, 3H), 1.72–1.69 (m, 1H), 1.60–1.29
(m, 13H), 1.15–1.09 (m, 1H), 1.00 (s, 3H), 0.90 (s, 9H), 0.89–0.85
(m, 4H), 0.83 (s, 3H), 0.66–0.65 (m, 2H), 0.58–0.57 (m, 2H). 13C
NMR (100 MHz, DMSO-d6) d 197.6, 171.6, 170.8, 162.4, 157.2,
59.5, 56.8, 55.0, 53.9, 53.3, 51.8, 47.9, 34.9, 34.8, 34.3, 32.1, 31.2,
29.9, 27.5, 27.4, 27.3, 26.7, 26.6, 25.4, 22.9, 21.1, 21.0, 19.2, 18.9,
14.6, 13.9, 12.9, 5.9. HRMS (ESI) calcd for C36H60N6O7S [M+H]+:
721.4335, found 721.4330.
5.2.17. (1R,5S)-N-[1(S)-[2-(Cyclopropylamino)-1,2-dioxoethyl-
butyl]-3-[2(S)-[[[[1-[[[(1,1-dimethylethyll)methylamino]sulfo-
nyl]methyl]cyclohexyl]amino]carbonyl]amino]-3,3-dimethyl-
1-oxobutyl]-6,6-dimethyl-3-azabicyclo[3.1.0]hexane-2(S)-
carboxamide (32)
1H NMR (500 MHz, DMSO-d6) d 8.73 (d, J = 5.0 Hz, 1H), 8.36 (d,
J = 6.9 Hz, 1H), 6.17 (d, J = 10.0 Hz, 1H), 5.98 (s, 1H), 4.96–4.93 (m,
1H), 4.28 (s, 1H), 4.17 (d, J = 9.7 Hz, 1H), 3.89 (d, J = 10.0 Hz, 1H),
3.77–3.71 (m, 1H), 3.68 (d, J = 14.1 Hz, 1H), 3.26 (d, J = 14.1 Hz,
1H), 2.76–2.72 (m, 1H), 2.71 (s, 3H), 2.18 (d, J = 11.0 Hz, 1H), 2.08
(d, J = 11.3 Hz, 1H), 1.71–1.67 (m, 1H), 1.52–1.30 (m, 11H), 1.31
(s, 9H), 1.14–1.04 (m, 1H), 0.99 (s, 3H), 0.89–0.85 (m, 13H), 0.81
(s, 3H), 0.68–0.63 (m,2H), 0.58–0.53 (m, 2H). 13C NMR (125 MHz,
DMSO-d6) d 197.1, 171.0, 170.4, 161.9, 156.7, 58.9, 57.5, 56.4,
53.4, 53.0, 47.3, 34.3, 33.9, 31.7, 31.6, 30.6, 28.9, 26.8, 26.1, 26.0,
24.9, 22.3, 20.6, 20.5, 20.4, 18.6, 18.3, 13.4, 12.4, 5.3, 5.2. HRMS
(ESI) calcd for C33H56N6O7S [M+H]+: 723.4492, found 723.4504.
5.2.21. (1R,5S)-N-[1(S)-[2-(Cyclopropylamino)-1,2-dioxoethyl]-
butyl]-3-[2(S)-[[[[1-[[[(cyclopropylmethyl)methylamino]sulfo-
nyl]methyl]cyclohexyl]amino]carbonyl]amino]-3,3-dimethyl-
1-oxobutyl]-6,6-dimethyl-3-azabicyclo[3.1.0]hexane-2(S)-
carboxamide (36)
1H NMR (400 MHz, DMSO-d6) d 8.58 (d, J = 4.7 Hz, 1H), 8.22 (d,
J = 7.0 Hz, 1H), 6.04 (d, J = 9.4 Hz, 1H), 5.83 (s, 1H), 4.81–4.77 (m,
1H), 4.13 (s, 1H), 4.01 (d, J = 9.4 Hz, 1H), 3.73 (d, J = 10.2 Hz, 1H),
3.58–3.55 (m, 1H), 3.44 (d, J = 14.1 Hz, 1H), 3.10 (d, J = 14.1 Hz,
1H), 2.73 (d, J = 7.0 Hz, 3H), 2.34 (br s, 1H), 2.00 (d, J = 10.9 Hz,
1H), 1.90 (d, J = 10.2 Hz, 1H), 1.59–1.50 (m, 1H), 1.35–1.12 (m,
12H), 1.04–0.96 (s, 1H), 0.83 (br s, 3H), 0.86–0.82 (m, 1H), 0.73
(br s, 9H), 0.71–0.69 (m, 5H), 0.65 (br s, 3H), 0.65–0.60 (m,1H),
0.49–0.48 (m, 2H), 0.42–0.39 (m, 2H), 0.33–0.31 (m, 2H), 0.02–
0.00 (m, 2H). 13C NMR (100 MHz, DMSO-d6) d 197.1, 171.1, 170.4,
161.9, 156.8, 58.9, 58.4, 53.4, 52.9, 52.6, 49.5, 47.4, 34.3, 34.3,
33.8, 33.3, 31.6, 30.6, 26.9, 26.2, 26.1, 25.9, 24.9, 24.7, 22.4, 20.5,
5.2.18. (1R,5S)-N-[1(S)-[2-(Cyclopropylamino)-1,2-dioxoethyl]-
butyl]-3-[2(S)-[[[[1-[[[(2-fluoro-1,1-dimethylethyl)methyl-
amino]sulfonyl]methyl]cyclohexyl]amino]carbonyl]amino]-
3,3-dimethyl-1-oxobutyl]-6,6-dimethyl-3-azabicyclo[3.1.0]-
hexane-2(S)-carboxamide (33)
1H NMR (500 MHz, DMSO-d6) d 8.73 (d, J = 5.0 Hz, 1H), 8.37 (d,
J = 6.6 Hz, 1H), 6.18 (d, J = 9.8 Hz, 1H), 6.00 (s, 1H), 4.98–4.94 (m,

S. L. Bogen et al. / Bioorg. Med. Chem. 18 (2010) 1854–1865
1863
18.7, 18.4, 18.2, 14.4, 13.4, 12.4, 5.4, 5.3. HRMS (ESI) calcd for
C36H60N6O7S [M+H]+: 721.4322, found 721.4328.
0.64 (m, 2H), 0.58–0.56 (m, 2H). 13C NMR (125 MHz, DMSO-d6) d
197.1, 171.0, 170.4, 161.9, 156.7, 65.7, 58.9, 56.4, 53.4, 53.2, 52.7,
47.3, 45.1, 34.4, 34.2, 33.8, 31.6, 30.6, 26.8, 26.6, 26.2, 26.0, 25.1,
24.8, 22.4, 20.9, 20.5, 18. 6, 18.4, 13.4, 12.4, 5.4, 5.3. HRMS (ESI)
calcd for C35H58N6O8S [M+H]+: 723.4128, found 723.4124.
5.2.22. (1R,5S)-N-[1(S)-[2-(Cyclopropylamino)-1,2-dioxoethyl]-
butyl]-3-[2(S)-[[[[1-[[(cyclopropylethylamino)sulfonyl]methyl]-
cyclohexyl]aminocarbonyl]amino]-3,3-dimethyl-1-oxobutyl]-
6,6-dimethyl-3-azabicyclo[3.1.0]hexane-2(S)-carboxamide (37)
1H NMR (400 MHz, DMSO-d6) d 8.72 (d, J = 5.4 Hz, 1H), 8.35 (d,
J = 7.0 Hz, 1H), 6.17 (d, J = 10.2 Hz, 1H), 5.99 (s, 1H), 4.93–4.91 (m,
1H), 4.68 (s, 1H), 4.16 (d, J = 10.9 Hz, 1H), 3.88 (d, J = 10.9 Hz, 1H),
3.72–3.67 (m, 2H), 3.29 (d, J = 14.0 Hz, 1H), 3.16–3.10 (m, 2H),
2.75–2.70 (m, 1H), 2.39–2.30 (m, 1H), 2.18 (d, J = 10.9 Hz, 1H),
2.06 (d, J = 10.9 Hz, 1H), 1.73–1.62 (m, 1H), 1.52–1.27 (m, 12H),
1.09 (t, J = 7.0 Hz, 3H), 0.97 (s, 3H), 0.87 (s, 9H), 0.86–0.81 (m,
4H), 0.79 (s, 3H), 0.70–0.69 (m, 2H), 0.63–0.60 (m, 4H), 0.55–0.54
(m, 2H). 13C NMR (100 MHz, DMSO-d6) d 197.6, 171.6, 170.8,
162.4, 157.3, 59.5, 56.9, 53.9, 53.4, 47.9, 44.9, 34.9, 34.8, 34.8,
34.4, 32.1, 31.2, 29.5, 29.2, 27.4, 26.7, 26.6, 26.4, 25.2, 22.9, 21.0,
19.2, 18.9, 14.5, 13.9, 12.9, 7.3, 7.2, 5.9. HRMS (ESI) calcd for
C37H60N6O7S [M+H]+: 721.4322, found 721.4329.
5.2.26. (1R,5S)-N-[1(S)-[2-(Cyclopropylamino)-1,2-dioxoethyl]-
butyl]-3-[(2S)-2-[[[[1-[1(R)-[(dimethylamino)sulfonyl]ethyl]-
cyclohexyl]amino]carbonyl]amino]-3,3-dimethyl-1-oxobutyl]-
6,6-dimethyll-3-azabicyclo[3.1.0]hexane-2(S)-carboxamide (41)
1H NMR (500 MHz, DMSO-d6) d 8.73 (d, J = 5.0 Hz, 1H), 8.36 (d,
J = 6.9 Hz, 1H), 6.26 (d, J = 10.1 Hz, 1H), 6.02 (s, 1H), 4.98–4.94 (m,
1H), 4.29 (s, 1H), 4.11 (t, J = 9.5 & 6.9 Hz, 1H), 3.94 (d, J = 10.4 Hz,
1H), 3.72 (dd, J = 5.4 & 10.1 Hz, 1H), 2.75 (s, 6H), 2.18 (d,
J = 12.9 Hz, 1H), 2.10 (d, J = 13.6 Hz, 1H), 1.74–1.66 (m, 2H), 1.55–
1.25 (m, 12H), 1.09 (d, J = 7.3 Hz, 3H), 1.00 (s, 3H), 0.90 (s, 9H),
0.89–0.85 (m, 5H), 0.82 (s, 3H), 0.66–0.64 (m, 2H), 0.58–0.56 (m,
2H). 13C NMR (125 MHz, DMSO-d6) d 197.1, 171.0, 170.6, 161.9,
156.9, 60.1, 58.9, 56.7, 56.1, 53.4, 47.4, 36.9, 33.9, 31.5, 30.6,
30.3, 26.9, 26.3, 26.1, 24.9, 22.4, 20.9, 20.4, 18.7, 18.4, 13.4, 12.4,
10.9, 5.3, 5.2. HRMS (ESI) calcd for C34H58N6O7S [M+H]+:
695.4166, found 695.4168.
5.2.23. (1R,5S)-N-[1(S)-[2-(Cyclopropylamino)-1,2-dioxoethyl]-
butyl]-3-[2(S)-[[[[1-[[[cyclopropyl(1-methylethyl)amino]-
sulfonyl]methyl]cyclohexyl]amino]carbonyl]amino]-3,3-di-
methyl-1-oxobutyl]-6,6-dimethyl-3-azabicyclo[3.1.0]hexane-
2(S)-carboxamide (38)
5.2.27. (1R,5S)-N-[1(S)-[2-(Cyclopropylamino)-1,2-dioxoethyl]-
butyl]-3-[(2S)-[[[[1-[1(S)-[(dimethylamino)sulfonyl]ethyl]-
cyclohexyl]amino]carbonyl]amino]-3,3-dimethyl-1-oxobutyl]-
6,6-dimethyll-3-azabicyclo[3.1.0]hexane-2(S)-carboxamide (42)
1H NMR (400 MHz, DMSO-d6) d 8.75 (d, J = 5.0 Hz, 1H), 8.38 (d,
J = 6.9 Hz, 1H), 6.30 (d, J = 9.8 Hz, 1H), 5.98 (s, 1H), 4.96–4.92 (m,
1H), 4.29 (s, 1H), 4.18 (d, J = 6.9 Hz, 1H), 4.06 (d, J = 10.4 Hz, 1H),
3.87 (d, J = 10.1 Hz, 1H), 3.74–3.71 (m, 1H), 2.74 (s, 7H), 2.26 (d,
J = 12.9 Hz, 1H), 1.81–1.71 (m, 2H), 1.56–1.23 (m, 14H), 1.14 (d,
J = 6.9 Hz, 3H), 0.99 (s, 3H), 0.89 (s, 9H), 0.87–0.84 (m, 2H), 0.81
(s, 3H), 0.65–0.63 (m, 2H), 0.58–0.54 (m, 2H). 13C NMR
(100 MHz, DMSO-d6) d 197.1, 171.0, 170.3, 161.9, 156.5, 60.7,
58.9, 56.4, 56.2, 53.4, 47.4, 36.9, 34.4, 31.6, 30.8, 30.6, 30.3, 26.8,
26.2, 26.0, 25.0, 22.6, 22.4, 20.9, 20.5, 18.7, 18.4, 13.4, 12.4, 10.9,
5.4. LC–MS for C34H58N6O7S [M+H]+: 695.4.
1H NMR (400 MHz, DMSO-d6) d 8.73 (d, J = 4.8 Hz, 1H), 8.36 (d,
J = 7.0 Hz, 1H), 6.16 (d, J = 9.4 Hz, 1H), 5.99 (s, 1H), 4.95–4.91 (m,
1H), 4.27 (s, 1H), 4.19–4.15 (m, 1H), 3.96–3.82 (m, 2H), 3.73 (d,
J = 14.1 Hz, 1H), 3.27 (d, J = 14.1 Hz, 1H), 2.76–2.70 (m, 1H), 2.24–
2.15 (m, 2H), 2.05 (d, J = 12.5 Hz, 1H), 1.73–1.24 (m, 13H), 1.18–
1.16 (m, 6H), 0.97 (s, 3H), 0.87 (br s, 10H), 0.86–0.82 (m, 4H),
0.79 (s, 3H), 0.78–0.74 (m, 4H), 0.65–0.61 (m, 2H), 0.57–0.51 (m,
2H). 13C NMR (100 MHz, DMSO-d6) d 197.6, 171.6, 170.9, 162.4,
157.2, 59.5, 57.2, 56.8, 53.9, 53.8, 53.5, 51.2, 47.9, 34.9, 34.5,
32.1, 31.2, 27.3, 26.7, 26.6, 25.4, 25,1, 22.9, 21.8, 21.6, 21.1, 19.2,
18.9, 14.5, 13.9, 12.9, 7.1, 7.0, 5.9, 5.8. HRMS (ESI) calcd for
C37H62N6O7S [M+H]+: 735.4478, found 735.4485.
5.2.24. (1R,5S)-3-[2(S)-[[[[1-[(1-Azetidinylsulfonyl)methyl]-
cyclohexyl]amino]carbonyl]amino]-3,3-dimethyl-1-oxobutyl]-
N-[1(S)-[2-(cyclopropylamino)-1,2-dioxoethyl]butyl]-6,6-
dimethyl-3-azabicyclo[3.1.0]hexane-2(S)-carboxamide (39)
1H NMR (400 MHz, DMSO-d6) d 8.75 (d, J = 5.4 Hz, 1H), 8.41 (d,
J = 6.3 Hz, 1H), 6.20 (d, J = 10.2 Hz, 1H), 5.99 (s, 1H), 4.98–4.93 (m,
1H), 4.28 (s, 1H), 4.17 (d, J = 10.2 Hz, 1H), 3.89 (d, J = 10.2 Hz, 1H),
3.74–3.69 (m, 6H), 3.68 (d, J = 14.8 Hz, 1H), 3.39 (d, J = 14.1 Hz, 1H),
2.76–2.67 (m, 1H), 1.73–1.65 (m, 1H), 1.53–1.27 (m, 12H), 1.13–
1.03 (m, 1H), 0.98 (s, 3H), 0.87–0.83 (m, 15H), 0.80 (s, 3H), 0.65–
0.61 (m, 2H), 0.57–0.53 (m, 2H). 13C NMR (100 MHz, DMSO-d6) d
197.1, 171.1, 170.3, 161.9, 156.7, 59.0, 56.4, 53.6, 53.4, 53.7, 47.4,
34.4, 34.3, 34.1, 33.9, 33.6, 33.4, 31.6, 26.8, 26.2, 26.0, 24.9, 22.4,
20.5, 18.7, 13.4, 12.5, 9.3, 5.3, 5.2, 3.4, 3.3. HRMS (ESI) calcd for
C34H56N6O7S [M+H]+: 693.4009, found 693.4015.
5.2.28. (1R,5S)-N-[3-(Cyclopropylamino)-1(S)-(2-cyclopropyl-
ethyl)-2,3-dioxopropyl]-3-[2(S)-[[[[1-[[[cycloppropyl(methyl)-
amino]sulfonyl]methyl]cyclohexyl]amino]carbonyl]amino]-
3,3-dimethyl-1-oxobutyl]-6,6-dimethyl-3-azabicyclo[3.1.0]-
hexane-2(S)-carboxamide (43)
1H NMR (500 MHz, CDCl3) d 7.79 (d, J = 7.8 Hz, 1H), 7.25 (d,
J = 6.6 Hz, 1H), 5.49–5.44 (m, 1H), 5.15 (s, 1H), 4.57 (br s, 2H),
4.20 (t, J = 10.7 Hz, 1H), 4.04 (s, 1H), 3.87 (dd, J = 10.4 & 5.4 Hz,
1H), 3.13 (d, J = 6.9 Hz, 1H), 2.96–2.90 (m, 1H), 2.82–2.78 (m,
1H), 2.64 (s, 3H), 2.61 (d, J = 11.9 Hz, 1H), 2.37 (d, J = 9.2 Hz, 1H),
2.23–2.14 (m, 1H), 1.93–1.85 (m, 1H), 1.79–1.69 (m, 1H), 1.60–
1.14 (m, 12H), 0.99 (s, 3H), 0.96 (br s, 9H), 0.92–0.86 (m, 5H),
0.84 (s, 3H), 0.82–0.81 (m, 2H), 0.65–0.62 (m, 2H). 13C NMR
(100 MHz, CDCl3) d 197.9, 172.5, 170.8, 160.3, 156.7, 63.7, 59.6,
57.3, 56.2, 54.1, 53.4, 48.6, 46.9, 35.2, 33.2, 32.1, 31.6, 30.9, 30.2,
29.9, 27.4, 26.4, 25.5, 22.6, 21.7, 20.9, 18.8, 18.7, 14.1, 13.2, 12.8,
6.3, 6.2. HRMS (FAB) calcd for C34H56N6O7S [M+H]+: 692.3978,
found 693.3981.
5.2.25. (1R,5S)-N-[1(S)-[2-(Cyclopropylamino)-1,2-dioxoethyl]-
butyl]-3-[3,3-dimethyl-2(S)-[[[[1-[(4-morpholinylsulfonyl)-
methyl]cyclohexyl]amino]carbonyl]amino]-1-oxobutyl]-6,6-
dimethyl-3-azabicyclo[3.1.0]hexane-2(S)-carboxamide (40)
1H NMR (400 MHz, DMSO-d6) d 8.73 (d, J = 5.3 Hz, 1H), 8.36 (d,
J = 6.9 Hz, 1H), 6.21 (d, J = 10.0 Hz, 1H), 6.20 (s, 1H), 4.97–4.93 (m,
1H), 4.28 (s, 1H), 4.17 (d, J = 10.0 Hz, 1H), 3.91 (d, J = 10.4 Hz, 1H),
3.74–3.71 (m, 1H), 3.60 (br s, 4H), 3.29 (d, J = 14.1 Hz, 1H), 3.04 (br
s, 4H), 2.76–2.72 (m, 1H), 2.16 (d, J = 12.0 Hz, 1H), 2.08 (d,
J = 12.0 Hz, 1H), 1.73–1.66 (m, 1H), 1.52–1.26 (m, 12H), 1.18–
1.08 (m, 1H), 0.99 (s, 3H), 0.89–0.84 (m, 13H), 0.82 (s, 3H), 0.66–
5.2.29. (1R,5S)-N-[1(S)-[2-(Cyclopropylamino)-1,2-dioxoethyl]-
butyl]-3-[2(S)-[[[[1-(2-cyclopropyl-1,1-dioxido-5(R)-isothiazoli-
dinyl)cyclohexyl]amino]carbonyl]amino]-3,3-dimethyl-1-oxo-
butyl]-6,6-dimethyl-3-azabicyclo[3.1.0]hexane-2(S)-carboxamide
(44)
1H NMR (400 MHz, DMSO-d6) d 8.73 (d, J = 4.7 Hz, 1H), 8.36 (d,
J = 7.0 Hz, 1H), 6.24 (d, J = 10.2 Hz, 1H), 6.09 (s, 1H), 4.96–4.91 (m,
1H), 4.27 (s, 1H), 4.20–4.03 (m, 2H), 3.88 (t, J = 10.2 Hz, 1H),

1864
S. L. Bogen et al. / Bioorg. Med. Chem. 18 (2010) 1854–1865
3.75–3.68 (m, 1H), 3.29 (d, J = 10.2 Hz, 1H), 3.16 (m, 1H), 3.01–2.88
(m, 1H), 2.75–2.68 (m, 1H), 2.45 (d, J = 11.8 Hz, 1H), 2.18–2.11 (m,
1H), 2.08–1.99 (m, 1H), 1.95–1.85 (m, 2H), 1.69–1.04 (m, 11H),
0.99 (s, 3H), 0.88–0.83 (m, 12H), 0.81–0.76 (m, 5H), 0.66–0.60
(m, 4H), 0.57–0.48 (m, 4H). 13C NMR (100 MHz, DMSO-d6) d
197.6, 171.6, 171.0, 162.4, 157.4, 64.7, 59.5, 58.2, 57.2, 55.4, 53.9,
50.8, 50.5, 47.8, 46.3, 34.5, 32.1, 30.5, 26.8, 26.6, 26.4, 25.5, 22.9,
21.0, 20.8, 19.2, 19.1, 18.9, 13.9, 12.8, 5.9, 5.6, 4.6, 4.5. HRMS
(ESI) calcd for C36H58N6O7S [M+H]+: 719.4166, found 719.4172.
tions were combined, dried with MgSO4, filtered and concentrated
in vacuuo. Flash chromatography purification (20–80% EtOAc/Hex-
ane) afforded 47 (1 g, 83% yield over two steps). Analytical HPLC
(YMC-Pack Diol NP column, 150 ꢃ 3 mm; 7% (CH3CN (0.3), i-PrOH
(1.7), DCM (2)) in Hexanes; 1 mL min; 254 nm), rt = 11.0 min, pur-
ity 97.0%. 1H NMR (400 MHz, DMSO-d6) d 8.75 (d, J = 4.7 Hz, 1H),
8.35 (d, J = 7.0 Hz, 1H), 6.23 (d, J = 10.2 Hz, 1H), 6.03 (s, 1H),
5.04–4.97 (m, 1H), 4.28 (s, 1H), 4.19 (d, J = 10.2 Hz, 1H), 3.91 (d,
J = 10.2 Hz, 1H), 3.73 (d, J = 14.1 Hz, 2H), 3.31 (d, J = 6.2 Hz, 1H),
2.78–2.72 (m, 1H), 2.70 (s, 3H), 2.40–2.30 (m, 1H), 2.23 (d,
J = 10.2 Hz, 1H), 2.11 (d, J = 10.9 Hz, 1H), 1.92–1.80 (m, 1H), 1.59–
1.07 (m, 14H), 1.00 (s, 3H), 0.90 (br s, 9H), 0.86 (br s, 3H), 0.67–
0.58 (m, 8H), 0.37–0.36 (m, 2H), 0.12–0.0 (m, 2H).13C NMR
(100 MHz, DMSO-d6) d 197.7, 171.6, 170.8, 162.5, 157.3, 59.5,
56.9, 54.0, 53.3, 52.3, 47.9, 37.0, 34.8, 34.3, 34.2, 31.5, 31.2, 31.0,
30.2, 27.4, 26.8, 26.6, 25.4, 22.9, 21.1, 20.6, 18.9, 13.0, 10.6, 7.5,
7.4, 5.9, 5.8, 4.9, 4.3. HRMS (ESI) calcd for C37H60N6O7S [M+H]+:
733.4335, found 733.4331.
5.2.30. (1R,5S)-N-[3-(Cyclopropylamino)-1(S)-(cyclopropyl-
methyl)-2,3-dioxopropyl]-3-[2(S)-[[[[1-[[[cyclopropyl(methyl)-
amino]sulfonyl]methyl]cyclohexyl]amino]carbonyl]amino]-
3,3-dimethyl-1-oxobutyl]-6,6-dimethyl-3-azabicyclo[3.1.0]-
hexane-2(S)-carboxamide (45)
1H NMR (400 MHz, DMSO-d6) d 8.74 (d, J = 4.7 Hz, 1H), 8.44 (d,
J = 6.2 Hz, 1H), 6.22 (d, J = 10.2 Hz, 1H), 6.02 (s, 1H), 5.08–5.03 (m,
1H), 4.31 (s, 1H), 4.19 (d, J = 10.2 Hz, 1H), 3.92 (d, J = 10.9 Hz, 1H),
3.72 (d, J = 14.1 Hz, 2H), 3.34 (t, J = 6.2 Hz, 1H), 2.69 (s, 3H), 2.33–
2.29 (m, 1H), 2.22 (d, J = 11.7 Hz, 1H), 2.10 (d, J = 10.9 Hz, 1H),
1.74–1.66 (m, 1H), 1.51–1.15 (m, 12H), 0.99 (s, 3H), 0.88 (br s,
10H), 0.81 (s, 3H), 0.67–0.56 (m, 8H), 0.41–0.36 (m, 2H), 0.10–
0.02 (m, 2H).;13C NMR (100 MHz, DMSO-d6) d 197.3, 171.5,
170.9, 162.2, 157.3, 59.5, 58.5, 56.9, 54.9, 53.3, 47.9, 38.7, 37.0,
35.5, 34.9, 34.8, 34.4, 31.5, 31.2, 27.3, 26.7, 26.6, 25.4, 22.9, 21.1,
18.9, 12.9, 8.4, 7.5, 7.4, 5.8, 5.5, 4.8, 4.6. HRMS (ESI) calcd for
C36H58N6O7S [M+H]+: 719.4166, found 719.4169.
Acknowledgments
The authors are grateful to the virology and DMPK groups for in
Vitro and in Vivo studies, respectively.
References and notes
1. (a) World health organization Fact sheet number 164, October 2000.; (b)
Wasley, A.; Alter, M. J. Semin. Liver Dis. 2000, 20, 1; (c) Brown, R. S., Jr.; Gaglio, P.
J. Liver Transpl. 2003, 9, S10; (d) Monto, A.; Wright, T. L. Semin. Oncol. 2001, 28,
441.
5.2.31. (1R,5S)-N-[1(S)-[2-(Cyclopropylamino)-1,2-dioxoethyl]-
pemtyl]-3-[2(S)-[[[[1-[[[cyclopropyl(methyl)amino]sulfonyl]-
methyl]cyclohexyl]amino]carbonyl]amino]-3,3-dimethyl-1-
oxobutyl]-6,6-dimethyl-3-azabicyclo[3.1.0]hexane-2(S)-
carboxamide (46)
2. Feld, J. J.; Hoofnagle, J. H. C. Nature 2005, 436, 967.
3. (a) Cuthbert, J. A. Reviews 1994, 7, 505; (b) Cohen, J. Science 1999, 285, 26; (c)
Alter, M. J.; Kruszon-Moran, D.; Nainan, O. V.; McQuillan, G. M.; Gao, F.; Moyer,
L. A.; Kaslow, R. A.; Margolis, H. S. N. Eng. J. Med. 1999, 341, 556; (d) Dymock, B.
W. Emerg. Drugs 2001, 6, 13; (e) De Francesco, R.; Migliaccio, G. Nature 2005,
436, 953; (f) Toniutto, P.; Fabris, C.; Pirisi, M. Expert Opin. Pharmacother. 2006, 7,
2025.
1H NMR (400 MHz, DMSO-d6) d 8.73 (d, J = 5.5 Hz, 1H), 8.35 (d,
J = 6.2 Hz, 1H), 6.20 (d, J = 10.2 Hz, 1H), 6.02 (s, 1H), 4.96–4.90 (m,
1H), 4.27 (s, 1H), 4.17 (d, J = 10.2 Hz, 1H), 3.89 (d, J = 10.9 Hz, 1H),
3.71 (d, J = 14.1 Hz, 2H), 3.31 (t, J = 6.2 Hz, 1H), 2.75–2.70 (m, 1H),
2.68 (s, 3H), 2.33–2.28 (m, 1H), 2.21 (d, J = 11.7 Hz, 1H), 2.09 (d,
J = 11.7 Hz, 1H), 1.74–1.69 (m, 1H), 1.53–1.04 (m, 15H), 0.98 (s,
3H), 0.88 (br s, 9H), 0.87–0.81 (m, 3H), 0.80 (s, 3H), 0.67–0.59
(m, 6H), 0.57–0.54 (m, 2H).13C NMR (100 MHz, DMSO-d6) d
197.6, 171.6, 170.9, 162.4, 157.3, 59.5, 58.5, 56.9, 54.0, 52.1, 47.9,
37.0, 34.8, 34.7, 34.3, 33.2, 33.0, 31.5, 31.0, 29.8, 28.0, 27.3, 26.7,
26.6, 25.4, 22.9, 22.2, 21.1, 19.3, 18.9, 14.2, 7.5, 7.4, 5.9. HRMS
(ESI) calcd for C36H60N6O7S [M+H]+: 721.4322, found 721.4328.
4. (a) Kolykhalov, A. A.; Mihalik, K.; Feinstone, S. M.; Rice, C. M. J. Virol. 2000, 74,
2046; (b) Bartenschlager, R.; Lohmann, V. J. Gen. Virol. 2000, 81, 1631.
5. (a) Narjes, F.; Koch, U.; Steinküler, C. Expert Opin. Invest. Drugs 2003, 12, 153; (b)
Llinas-Brunet, M.; Bailey, M. D.; Bolger, G.; Brochu, C.; Faucher, A.-M.; Ferland,
J. M.; Garneau, M.; Ghiro, E.; Gorys, V.; Grand-Maitre, C.; Halmos, T.; Lapeyre-
Paquette, N.; Liard, F.; Poirier, M.; Rheaume, M.; Tsantrizos, Y. S.; Lamarre, D. J.
Med. Chem. 2004, 47, 1605; (c) Perni, R. B.; Farmer, L. J.; Cottrell, K. M.; Court, J.
J.; Courtney, L. F.; Deininger, D. D.; Gates, C. A.; Harbeson, S. L.; Kim, J. L.; Lin, C.;
Lin, K.; Luong, Y.-P.; Maxwell, J. P.; Murcko, M. A.; Pitlik, J.; Rao, B. G.; Schairer,
W. C.; Tung, R. D.; Van Drie, J. H.; Wilson, K.; Thomson, J. A. Bioorg. Med. Chem.
Lett. 2004, 14, 1939; (d) Lamar, J.; Victor, F.; Snyder, N.; Johnson, R. B.; Wang, Q.
M.; Glass, J. I.; Chen, S.-H. Bioorg. Med. Chem. Lett. 2004, 14, 263; (e) Nizi, E.;
Koch, U.; Ontoria, J. M.; Marchetti, A.; Narjes, F.; Malancona, S.; Matassa, V. G.;
Gardelli, C. Bioorg. Med. Chem. Lett. 2004, 14, 2151; (f) Priestley, E. S.; De Lucca,
I.; Ghavimi, B.; Erickson-Viitanen, S.; Decicco, C. P. Med. Chem. Lett. 2002, 12,
3199; (g) Arasappan, A.; Njoroge, F. G.; Parekh, T. N.; Yang, X.; Pichardo, J.;
Butkiewicz, N.; Prongay, A.; Yao, N.; Girijavallabhan, V. Bioorg. Med. Chem. Lett.
2004, 14, 5751.
6. For BILN-2061, see: (a) Lamarre, D.; Anderson, P. C.; Bailey, M.; Beaulieu, P.;
Bolger, G.; Bonneau, P.; Bös, M.; Cameron, D. R.; Cartier, M.; Cordingley, M. G.;
Faucher, A.-M.; Goudreau, N.; Kawai, S. H.; Kukolj, G.; Lagacé, L.; LaPlante, S. R.;
Narjes, H.; Poupart, M.-A.; Rancourt, J.; Sentjens, R. E.; George, T. S.; Simoneau,
B.; Steinmann, G.; Thibeault, D.; Tsantrizos, Y. S.; Weldon, S. M.; Yong, C.-L.;
Llinàs-Brunet, M. Nature 2003, 426, 186; (b) Tsantrizos, Y. S.; Bolger, G.;
Bonneau, P.; Cameron, D. R.; Gordreau, N.; Kukolj, G.; LaPlante, S. R.; Llinas-
Brunet, M.; Nar, H.; Lamarre, D. Angew. Chem., Int. Ed. 2003, 42, 1355.
7. For ITMN-191, see: 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.
5.2.32. (1S,5R)-N-((S)-5-Cyclopropyl-1-(cyclopropylamino)-1,2-
dioxopentan-3-yl)-3-((S)-2-(3-(1-((N-cyclopropyl-N-methyl-
sulfamoyl)methyl)cyclohexyl)ureido)-3,3-dimethylbutanoyl)-
6,6-dimethyl-3-azabicyclo[3.1.0]hexane-2-carboxamide (47)
To the acid 6 (R3 = c-Pr, R2 = Me, R4 = H), (1.2 equiv, 907 mg,
1.68 mmol) in DCM (60 mL) was added amine hydrochloride 7 d
(1 equiv, 1.4 mmol, 349 mg) with stirring on ice. To this solution
was added HATU (1.2 equiv, 1.68 mmol, 638 mg) followed by DI-
PEA (60 mmol, 10.2 mL). The reaction was warmed-up to rt and left
stirring overnight. The reaction mixture was diluted with EtOAc
and washed with 1 N HCl, NaHCO3 then brine. The organic layer
was dried over MgSO4, filtered and concentrated in vacuuo. The
intermediate product, a-hydroxyamide, was obtained as a mixture
8. For TMC435350, see: Raboisson, P.; De Kock, H.; Rosenquist, Å.; Nilsson, M.;
Salvador-Oden, L.; Lin, T.; Roue, N.; Ivanov, V.; Wähling, H.; Wickström, K.;
Hamelink, E.; Edlung, M.; Vrang, L.; Vendeville, S.; Van de Vreken, W. 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.
9. For MK-7009, see: (a) 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; (b) McCauley, J. A.; Rudd, M. T.;
of diastereomers (1.35 g) which was used in subsequent reaction
without further purification. To the solution of this product
(1.35 g) in anhydrous CH2Cl2 (30 mL) at rt was added Dess–Martin
reagent (1.66 g, 3.92 mmol). The mixture was stirred for 3 h. Satu-
rated NaHCO3 and Na2S2O3 solutions (20 mL each) were added.
After stirring for 10 min, the layers were separated. The aqueous
solution was extracted with EtOAc (2 ꢃ 50 mL). The organic solu-

S. L. Bogen et al. / Bioorg. Med. Chem. 18 (2010) 1854–1865
1865
Nguyen, K. T.; McIntyre, C. J.; Romano, J. J.; Bush, K. J.; Varga, S. L.; Ross, C. W.,
III; Carroll, S. S.; DiMuzio, J.; Stahlhut, M. W.; Olsen, D. B.; Lyle, T. A.; Vacca, J. P.;
Liverton, N. J. Angew. Chem., Int. Ed. 2008, 47, 9104; (c) McCauley, J. A.; Rudd, M.
T.; McIntyre, C. J.; Nguyen, K. T.; Romano, J. J.; Butcher, J. W.; Holloway, M. K.;
Wan, B.-L.; Carroll, S. S.; DiMuzio, J. M.; Graham, D. J.; Ludmerer, S. W.; Mao, S.-
S.; Stahlhut, M.; Fandozzi, C.; Trainor, N.; Olsen, D. B.; Vacca, J. P.; Liverton, N. J.
Abstracts of Papers, 235th ACS National Meeting, New Orleans, LA, United
States, April 6–10, 2008; American Chemical Society: Washington, DC, 2008;
MEDI-018.
L.; Khunvichai, A.; McHutchison, J. G. J. Hepatol. 2008, 49, 163; (e) Mederacke,
I.; Wedemeyer, H.; Manns, M. P. Curr. Opin. Invest. Drugs 2009, 10, 181.
14. Bogen, S.; Weidong, P.; Ruan, S.; Nair, L. G.; Arasappan, A.; Bennett, F.; Chen, K.
X.; Jao, E.; Venkatraman, S.; Vibulbhan, B.; Liu, R.; Cheng, K. C.; Guo, Z.; Tong,
X.; Saksena, A. K.; Girijavallabhan, V.; Njoroge, F. G. J. Med. Chem. 2009, 52,
3679.
15. Dess, D. B.; Martin, J. C. J. Am. Chem. Soc. 1991, 113, 7277.
16. (a) Curtius, T. Chem. Ber. 1890, 23, 3023; (b) Shioiri, T.; Ninomiya, K.; Yamada, S.
J. Am. Chem. Soc. 1972, 94, 6203.
10. (a) Zhang, R.; DurKin, J. P.; Windsor, W. T. Bioorg. Med. Chem. Lett. 2002, 12,
1005; (b) Bogen, S. L.; Saksena, A. K.; Arasappan, A.; Gu, H.; Njoroge, F. G.;
Girijavallabhan, V.; Pichardo, J.; ButKiewicz, N.; Prongay, A.; Madison, V. Bioorg.
Med. Chem. Lett. 2005, 15, 4515.
17. Garner, P.; Park, J. M. J. Org. Chem. 1987, 52, 2364.
18. For reviews, see: (a) de Nooy, A. E. J.; Besemer, A. C.; van Bekkum, H. Synthesis
1996, 1153; (b) Anelli, P. L.; Biffi, C.; Montanari, F.; Quici, S. J. Org. Chem. 1987,
52, 2559.
11. (a) Han, W.; Hu, Z.; Jiang, X.; Decicco, C. P. Bioorg. Med. Chem. Lett. 2000, 10,
711; (b) Victor, F.; Lamar, J.; Snyder, N.; Yip, Y.; Guo, D.; Yumibe, N.; Johnson, R.
B.; Wang, Q. M.; Glass, J. I.; Chen, S.-H. Bioorg. Med. Chem. Lett. 2004, 14, 257.
12. For SCH 503034, see: (a) Njoroge, F. G.; Chen, K. X.; Shih, N.-Y.; Piwinski, J. Acc.
Chem. Res. 2008, 41, 50; (b) Venkatraman, S.; Bogen, S. L.; Arasappan, A.;
Bennett, F.; Chen, K.; Jao, E.; Liu, Y.-T.; Lovey, R.; Hendrata, S.; Huang, Y.; Pan,
W.; Parekh, T.; Pinto, P.; Popov, V.; Pike, R.; Ruan, S.; Santhanam, B.; Vibulbhan,
B.; Wu, W.; Yang, W.; Yang, W.; Kong, J.; Liang, X.; Wong, J.; Liu, R.; Butkiewicz,
N.; Chase, R.; Hart, A.; Agarwal, S.; Ingravallo, P.; Pichardo, J.; Kong, R.; Baroudy,
B.; Malcolm, B.; Guo, Z.; Prongay, A.; Madison; Broske, L.; Cui, X.; Cheng, K.-C.;
Hsieh, T. Y.; Brisson, J.-M.; Prelusky, D.; Kormacher, W.; White, R.;
Bogonowich-Knipp, S.; Pavlovsky, A.; Prudence, B.; Saksena, A. K.; Ganguly,
A.; Piwinski, J.; Girijavallabhan, V.; Njoroge, F. G. J. Med. Chem. 2006, 49, 6074.
13. (a) Zeuzem, S.; Sarrazin, C.; Rouzier, R.; Tarral, A.; Brion, N.; Forestier, N.;
Gupta, S.; Deckman, D.; Fellows, K.; Hussain, M.; Cutler, D.; Zhang, J. In 56th
Annual Meeting of AASLD, 2005, San Francisco, CA, USA.; For combination
19. (a) Passerini, M.; Ragni, G. Gazz. Chim. Ital. 1931, 61, 964; (b) Marquarding, D.;
Gokel, G.; Hoffmann, P.; Ugi, I. Isonitrile Chemistry; Academic Press: New York,
1971. Chapter 7; (c) Falck, J. R.; Manna, S. Tetrahedron Lett. 1981, 22, 619.
20. (a) Velazquez, F.; Venkatraman, S.; Njoroge, F. G. WO 2005058821, 2005.; (b)
Chen, A.-H.; Lamar, J.; Yip, Y.; Victor, F.; Johnson, R. B.; Wang, Q. M.; Glass, J. I.;
Heinz, B.; Colacino, J.; Guo, D.; Tebbe, M.; Munroe, J. E. Lett. Drug Des. Discovery
2005, 2, 118; (c) Bogen, S.; Saksena, A. K.; Arasappan, A.; Gu, H.; Njoroge, F. G.;
Girijavallabhan, V.; Pichardo, J.; Butkiewicz, N.; Prongay, A.; Madison, V. Bioorg.
Med. Chem. Lett. 2006, 16, 1621.
21. Zhang, R.; Beyer, B. M.; Durkin, J.; Ingram, R.; Njoroge, F. G.; Windsor, W. T.;
Malcolm, B. A. Anal. Biochem. 1999, 270, 268. The substrate Ac-DTEDVVP(Nva)-
O-PAP was used in the present study.
22. Lohmann, V.; Korner, F.; Koch, J.-O.; Herian, U.; Theilmann, L.; Bartenschlager,
R. Science 1999, 285, 110.
23. (a) Chen, K. X.; Nair, L.; Vibulbhan, B.; Yang, W.; Arasappan, A. L.; Bogen, S. L.;
Venkatraman, S.; Bennett, F.; Pan, W.; Blackman, M. L.; Padilla, A. I.; Prongay,
A.; Cheng, K.-C.; Tong, X.; Shih, N.-Y.; Njoroge, F. G. J. Med. Chem. 2009, 52,
1370; (b) Arasappan; A; Padilla, A. I.; Jao, E.; Bennett, F.; Bogen, S. L.; Chen, K.
X.; Pike, R. E.; Sannigrahi, M.; Soares, J.; Venkatraman, S.; Vibulbhan, B.;
Saksena, A. K.; Girijavallabhan, V.; Tong, X.; Cheng, K. C.; Njoroge, F. G. J. Med.
Chem. 2009, 52, 2806; (c) Venkatraman, S.; Blackman, M.; Wu, W.; Nair, L.;
Arasappan, A.; Padilla, A.; Bogen, S.; Bennett, F.; Chen, K.; Pichardo, J.; Tong, X.;
Prongay, A.; Cheng, K. C.; Girijavallabhan, V.; Njoroge, F. G. Bioorg. Med. Chem.
Lett. 2009, 13, 4486.
therapy with pegylated interferon
a-2b see: (b) Sarrazin, C.; Rouzier, R.;
Wagner, F.; Forestier, N.; Larrey, D.; Gupta, S. K.; Hussain, M.; Shah, A.; Cutler,
D.; Zhang, J.; Zeuzem, S. Gastroenterology 2007, 132, 1270; (c) 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; (d) Lawitz, E.; Rodriguez-Torres, M.; Muir, A. J.; Kieffer, T. L.; McNair,