P1-Substituted Symmetry-Based Human Immunodeficiency Virus Protease Inhibitors with Potent Antiviral Activity against Drug-Resistant Viruses

Article abstract of DOI:10.1021/jm201109t

Because there is currently no cure for HIV infection, patients must remain on long-term drug therapy, leading to concerns over potential drug side effects and the emergence of drug resistance. For this reason, new and safe antiretroviral agents with improved potency against drug-resistant strains of HIV are needed. A series of HIV protease inhibitors (PIs) with potent activity against both wild-type (WT) virus and drug-resistant strains of HIV was designed and synthesized. The incorporation of substituents with hydrogen bond donor and acceptor groups at the P1 position of our symmetry-based inhibitor series resulted in significant potency improvements against the resistant mutants. By this approach, several compounds, such as 13, 24, and 29, were identified that demonstrated similar or improved potencies compared to 1 against highly mutated strains of HIV derived from patients who previously failed HIV PI therapy. Overall, compound 13 demonstrated the best balance of potency against drug resistant strains of HIV and oral bioavailability in pharmacokinetic studies. X-ray analysis of an HIV PI with an improved resistance profile bound to WT HIV protease is also reported.

Full text of DOI:10.1021/jm201109t

ARTICLE
pubs.acs.org/jmc
P1-Substituted Symmetry-Based Human Immunodeficiency Virus
Protease Inhibitors with Potent Antiviral Activity against
Drug-Resistant Viruses
David A. DeGoey,* David J. Grampovnik, Hui-Ju Chen, William J. Flosi, Larry L. Klein,† Tatyana Dekhtyar,
Vincent Stoll, Mulugeta Mamo, Akhteruzzaman Molla, and Dale J. Kempf
Antiviral Research, Global Pharmaceutical Research and Development, Abbott Laboratories, 100 Abbott Park Road, Abbott Park, Illinois
60064, United States
ABSTRACT: Because there is currently no cure for HIV infection, patients must
remain on long-term drug therapy, leading to concerns over potential drug side
effects and the emergence of drug resistance. For this reason, new and safe
antiretroviral agents with improved potency against drug-resistant strains of HIV
are needed. A series of HIV protease inhibitors (PIs) with potent activity against both
wild-type (WT) virus and drug-resistant strains of HIV was designed and synthe-
sized. The incorporation of substituents with hydrogen bond donor and acceptor
groups at the P1 position of our symmetry-based inhibitor series resulted in
significant potency improvements against the resistant mutants. By this approach,
several compounds, such as 13, 24, and 29, were identified that demonstrated similar or improved potencies compared to 1 against
highly mutated strains of HIV derived from patients who previously failed HIV PI therapy. Overall, compound 13 demonstrated the
best balance of potency against drug resistant strains of HIV and oral bioavailability in pharmacokinetic studies. X-ray analysis of an
HIV PI with an improved resistance profile bound to WT HIV protease is also reported.
’ INTRODUCTION
the Arg8 residue via π stacking. The analysis also suggested that
the tertiary alcohol binding region could potentially be accessed
by substituents attached to the P1 group, due to their close spatial
proximity. We speculated that the introduction of functional
groups at the P1 position of our previously described pseudo-C2-
symmetric cores that could mimic the interactions of the tertiary
hydroxyl group of 1 might provide an alternative approach for the
discovery of HIV PIs with improved resistance profiles. We chose
to study P1-substituted analogues of one of our previously
described pseudo-C2-symmetric cores (Figure 1), obtained by
capping the P2 group with a methyl carbamate. While the
hydroxyl group regiochemistry and P10 stereochemistry of the
new analogues differ from 1, we showed previously that both of
the core configurations result in potent compounds against the
WT virus and that the P3 group was critical for activity against the
drug-resistant viruses.9 As expected, the initial analogue 10 with
the 2-pyridyl P1 group was not highly active against drug-
resistant HIV mutants, although subsequent analogues with
modified P1 groups demonstrated improved resistance profiles.
In this report, the synthesis and biological evaluation of HIV PIs
having P1 groups substituted with hydrogen bond donor and
acceptor groups are described.
The treatment of HIV infection with highly active antiretro-
viral therapy (HAART) has dramatically reduced the rate of
disease progression to AIDS and the morbidity and mortality rate
associated with it.1 Because no cure for HIV infection is available,
however, patients must remain on long-term drug therapy,
leading to concerns over potential drug side effects and the
emergence of drug resistance. Consequently, a need exists to
develop new and safe antiretroviral agents with improved
potency against drug-resistant strains of HIV. Significant pro-
gress has been made toward the discovery of HIV PIs with
improved resistance profiles compared to the first generation of
compounds. For example, the analysis of crystal structures of
HIV protease in enzymeꢀligand complexes has enabled struc-
ture-based drug design and has contributed to the understanding
of the molecular basis for drug resistance.2 Several marketed
HIV protease inhibitors (PIs), including lopinavir, darunavir,
and tipranavir (Figure 1), have improved potency against drug-
resistant mutants compared to the first generation of drugs.3,4 In
addition, several reports on preclinical compounds with im-
proved resistance profiles have also appeared.5ꢀ8 We recently
reported on compound 1 (A-790742, Figure 1), which demon-
strated excellent potency against HIV PI-resistant clinical
isolates.9,10 A unique structural feature of compound 1 that
contributed to its superior resistance profile was the P3 tertiary
hydroxyl group. X-ray analysis of compound 1 bound to WT HIV
protease (Figure 2) demonstrated that this hydroxyl functional
group occupies a solvent exposed region adjacent to the hydro-
phobic S1 binding site, with the P3 pyridine ring interacting with
’ CHEMISTRY
As shown in Scheme 1, compounds 10ꢀ30 were synthesized
from the triflates 6, 7, 8, or 9 through palladium-mediated
Received: May 26, 2011
Published: September 07, 2011
r
2011 American Chemical Society
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Figure 1. Structures of 1, some marketed HIV PIs, and the design of P1-substituted HIV PIs.
carbamate nitrogen during the palladium catalyzed coupling.
While 6 reacted smoothly in Stille coupling reactions, it was
subsequently discovered that a more direct synthesis with a
simpler protection scheme was possible. For example, 7 reacted
efficiently in Suzuki cross coupling reactions, and similar yields of
coupled products were obtained by employing 8 or 9, which had
one or both of the tert-leucine peptide end-caps already in place.
Deprotection of products resulting from palladium catalyzed
couplings with 6, 7, and 8 using standard conditions followed by
coupling with the tert-leucine end-caps gave the final products,
while palladium catalyzed coupling with 9 gave the final products
directly.
’ RESULTS AND DISCUSSION
Biological data for these compounds were summarized in
Table 1. Antiviral activity was evaluated against WT virus with
and without the addition of 50% human serum (HS), as well as
against two resistant mutants, A17 and B26, derived from in vitro
selection with lopinavir (LPV).10 Attenuation of potency by
binding to human serum proteins has been shown to be clinically
relevant for HIV PIs, and measurement of in vitro EC50s in the
presence of 50% HS has demonstrated utility in the context
of pharmacokineticꢀpharmacodynamic modeling.13 As described
previously,10 the mutant viruses had key mutations in the
protease at positions that confer resistance to marketed HIV
PIs, including lopinavir, atazanavir, and darunavir. Compound
10, which was substituted with a 2-pyridyl group at the P1
position, demonstrated potency against the WT virus, although
the fold resistance observed against the mutants was 4- to 7-fold
higher than that observed for 1. Altering the position of the
pyridine nitrogen to either the 3- or 4-position as in compounds
11 and 12, respectively, resulted in a slight decrease in WT
potency and improvement in activity against the resistant
mutants, which demonstrated only 2- to 3-fold resistance to 11
and 12. An X-ray crystal structure of 11 bound to WT HIV
protease (Figure 3) was obtained in an effort to understand
the origins of its improved resistance profile. While no direct
Figure 2. X-ray of 1 bound to WT HIV protease. Residue Arg 8 is
highlighted to illustrate the π stacking interaction with the P3 pyridine
ring. The P1 and P3 groups are in close proximity, suggesting that
substituents attached to P1 may access the S3 binding region.
coupling with the appropriate boronic acid or stannane reagent.
Tyrosine was benzylated as previously reported,11 and reaction
with sodioacetonitrile resulted in nitrile 2, which was treated with
benzyl Grignard reagent to give the enaminone 3. A high degree
of stereocontrol was observed for the stepwise reduction of 3 by
using a similar procedure to that reported12 for an analogous
enaminone to give 4, following Boc protection of the resulting
amine. Removal of the benzyl protecting groups through hydro-
genolysis gave the amine 5. The triflates were generated using N-
phenyl-bis(trifluoromethanesulfonimide), and a number of pro-
tection schemes, such as those found in 6, 7, 8, and 9, were
compatible with either Suzuki or Stille coupling reactions.
Compound 6 was employed initially based on the consideration
that it would be beneficial to mask the central hydroxyl group and
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Scheme 1. Synthesis of HIV PIs 10ꢀ30a
a Reagents and conditions: (a) NaHMDS, CH3CN; (b) BnMgCl; (c) (i) NaBH4, CH3SO3H, (ii) NaBH4, TFA; (d) Boc2O; (e) Pd(OH)2 on C, H2;
(f) Cbz-Osu; (g) N-phenyl-bis(trifluoromethanesulfonimide); (h) 2,2-dimethoxypropane; (i) DEPBT, MeO2C-t-Bu-Gly-OH; (j) 4 N HCl in dioxane;
(k) Cl2Pd(PPh3)2, LiCl, RSn(Bu)3, DMF; (l) Cl2Pd(PPh3)2, RB(OH)2, Na2CO3, DMF.
hydrogen bounds between 11 and the enzyme were observable,
the region occupied by the pyridine ring was exposed to the
aqueous environment. Consequently, the 3-pyridyl nitrogen
atom of 11 may be more accessible for the formation of water-
mediated hydrogen bonds with the protein or to contribute to
solvent anchoring effects.7 The X-ray analysis also indicated that
the twist angle of 20ꢀ30° for the 3-phenylpyridine P1 side chain
of 11 was larger than the relatively planar angle (approximately 5°)
observed for the 2-phenylpyridine P10 group of 1, an observa-
tion supported by the literature.14 The larger twist angle of the
pyridine of 11 may allow for increased van der Waals inter-
actions with Pro81, and this increased interaction with the
protein may have greater impact for resistant viruses where
neighboring residues are mutated in A17 (I84 V) and B26
(V82F).
substitution of electron withdrawing substituents at the 2-posi-
tion, such as fluorine (14) and cyano (16), resulted in decreased
potency against the resistant mutants, while the WT potency was
maintained. Substitution of such groups at the 2-position more
significantly reduces the basicity of the pyridine ring than sub-
stitution atthe 3-position,15 suggesting thatthe charged group may
enhance the resistance profile. A similar reduction in potency
against the mutant viruses was observed when compound 12 was
substituted with a fluorine at the 2-position, as in compound 15.
Because subtle structural changes to the pyridine ring system
affected the resistance profile, the effect of substituting the P1
position with additional nitrogen-based heterocycles was exam-
ined. For example, the pyrazine analogue 18 lost potency against
the WT virus and the resistant mutants, while the pyrimidine
analogue 19 retained WT potency and had significantly higher-
fold resistance against the resistant mutants. Both of these
heterocycles are significantly less basic than the pyridines found
in 11 or 12, again suggesting that the protonated forms may
Substitution of compound 11 with a fluorine at the 3-position
resulted in compound 13, which had improved WT potency
and maintained low-fold resistance for the mutants. In contrast,
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Table 1. In Vitro Cell Culture Potency
c
a pNL4ꢀ3, no HS added. b pNL4ꢀ3, 50% HS added. A17 contains the mutations L10F, V32I, M46I, I47V, Q58E, and I84V. d B26 contains the
mutations L33F, K45I, M46I, I50V, I54V, A71V, and V82F.
contribute to the potency of the pyridine analogues. Compound
20 which was substituted with a quinoline group retained WT
potency, although its potency against the resistant mutants was
diminished.
In general, the addition of polar functional groups with
hydrogen bonding donor or acceptor groups to the P1 biaryl
system was well-tolerated for potency against the WT virus and
several compounds had improved potency against the resistant
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Table 2. Activity against HIV-1 Molecular Clones Containing
Proteases Derived from PI-Resistant Patient Isolates
fold change in EC50 relative to WT
no.
virus 1a
virus 2b
LPV
1
62
57
29
38
58
30
16
12
33
52
45
7
234
2
11
13
14
15
16
17
20
22
23
24
26
27
29
30
17
2
7
2
3
2
12
4
2
1
28
34
9
4
18
1
Figure 3. X-ray crystal structure of 11 bound to WT HIV protease. The
biaryl twist angle of 20ꢀ30° may enhance hydrophobic contacts with
Pro81, while the 3-phenylpyridine nitrogen is accessible for interactions
with solvent water molecules. Distances are shown in Å.
45
7
a Virus 1 contains the mutations L10I, E35D, N37D, M46I, I54V, G57R,
L63P, A71V, T74P, I84V, L90M, I93L. b Virus 2 contains the mutations
L10I, I13V, G16A, Q18H, L33F, N37D, M46I, I54V, G57R, Q61H,
I62V, L63P, A71L, I72T, L76V, V77I, V82A, N88G, L90M, I93L.
mutants. For example, compound 17, which resulted from the
addition of a hydroxymethyl group at the 2-position of com-
pound 11, maintained potency against the WT virus, while the
resistant mutants demonstrated hypersensitivity to this com-
pound. In addition to the heterocyclic P1 groups described
above, a variety of substituted biphenyl compounds were also
surveyed. While the unsubstituted parent compound 21 had
similar potency to compound 10 against the WT and the drug-
resistant viruses, the introduction of hydrogen bond donating
groups, such as hydroxymethyl (21 and 23), phenol (28), and
amines (29 and 30), generally resulted in improved potency
against the resistant mutants. Compounds 23 and 29 combined
the attractive features of excellent potency against the WT virus
along with low-fold resistance versus the mutants. Compounds
with hydrogen bond accepting groups alone, such as acetate (26)
and methoxy (27), demonstrated superior potency against the
WT virus but lacked any improvement against the resistant
mutants. Compounds bearing an amide which provided both
hydrogen bond donor and acceptor groups, such as 24 and 25,
exhibited a lack of resistance for the mutant viruses, while the
para-substituted isomer (24) was 40-fold more potent than the
meta-substituted isomer (25) against the WT virus.
Viruses obtained from patients who have failed HIV PI
therapy often have proteases with a large number of mutations,
in addition to those found in the A17 and B26 mutants.10,16 To
determine the potential effectiveness of these compounds at
inhibiting this type of drug-resistant virus, compounds that
demonstrated low-fold resistance against the A17 and B26
viruses were also tested against two HIV molecular clones
containing protease genes derived from patient isolates
(Table 2). Viruses 1 and 2 were highly resistant to LPV, while
virus 1 was highly resistant and virus 2 was susceptible to
compound 1. Several of the new compounds showed similar
activity against viruses 1 and 2 compared to compound 1, such as
13, 15, 22, 23, and 26. Four of the compounds (16, 17, 24, and
29), however, showed improvement in their activity against virus
Table 3. Oral Pharmacokinetic Data in Rats (5 mg/kg)
no RTV
w/RTVa
b
b
no.
F (%)
Cmax
AUCc
F (%)d
Cmax
AUCc
10
11
13
20
23
26
27
29
7
5
0.28
0.18
0.11
0.02
0
0.19
0.16
0.16
0.03
0
>100
25
1.55
0.43
0.47
0.22
0.01
0.05
0.05
0.10
4.88
0.74
3.22
1.85
0.01
0.22
0.27
0.07
13
1
>100
63
0
0.3
27
0
0
0
0
0
0
14
1
0.1
0.02
5
a Coadministered with 5 mg/kg RTV. b μg/mL. c μg h/mL. d Relative to
3
IV dose without RTV coadministration.
1 compared to LPV or compound 1. Against virus 2, all of the
compounds demonstrated superior potency compared to LPV.
Two compounds, 24 and 29, demonstrated less than 10-fold
resistance to both of these highly resistant clones.
Compounds with potent activities against the WT virus in the
presence of HS and promising resistance profiles were selected
for further pharmacokinetic and drug safety evaluation (Table 3).
Similar to compounds in our P3-substituted series, our P1-
substituted analogues showed moderate stability in human liver
microsomes (HLM) in vitro (30ꢀ40% disappearance in 20 min)
and significantly higher clearance rates in rat liver microsomes.
Microsomal stability was greatly improved in the presence of
0.4 μM ritonavir (RTV), a potent inhibitor of CYP3A mediated
metabolism. For example, while compounds 10, 11, and 13
demonstrated similar microsomal stability in vitro (40% disappear-
ance in HLM with 20 min incubation), no appreciable metabolism
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was observed in the presence of RTV. In rat pharmacokinetic
studies, 2-pyridyl compound 10 demonstrated low plasma expo-
sures when dosed alone orally and a 25-fold increase in AUC upon
coadministration with RTV. In contrast, 3-pyridyl compound 11
demonstrated relatively low exposures when dosed alone orally
(F = 5%) or with coadmininstration of RTV (F = 25%). While com-
pound 13 showed similarly low exposures when dosed alone orally
(F = 12%), it demonstrated much higher plasma exposures than 11
with coadmininstration of RTV. Compound 20 also demon-
strated significant pharmacokinetic enhancement upon coad-
ministration of RTV, although it was less potent against the
drug-resistant mutants. Other compounds bearing hydrogen
bond acceptor groups on the P1 substituent, such as 26 and 27,
also demonstrated improved plasma levels upon coadministra-
tion with RTV, although the exposures were significantly less
that those observed for 13. Compounds bearing hydrogen
bond donor groups on the P1 substituent, such as 23 and 29,
generally showed poor oral bioavailability and low plasma
exposures, even with coadministration of RTV. Overall, com-
pound 13 demonstrated the best balance of potency against
drug resistant strains of HIV and oral bioavailability in the rat.
As a result, compound 13 was characterized in dog pharmaco-
kinetic studies and it demonstrated comparable plasma levels to
1 when coadministered orally with RTV (5 mg/kg 13 with
5 mg/kg RTV, AUC = 7.0). Additional profiling of compound 13
revealed that, like many HIV PIs, it demonstrated inhibition of
CYP3A4 (IC50 = 0.14 μM). In addition, 13 demonstrated
moderate permeability (7.3 ꢁ 10ꢀ6 cm/s) and comparable
aqueous solubility to 1 (10.4 μM).
final compounds were purified to >95% purity as determined by high-
performance liquid chromatography (HPLC). Silica gel chromatogra-
phy was performed using either glass columns packed with silica gel 60
(230ꢀ400 mesh) or prepacked silica gel cartridges (Biotage, 32ꢀ63
μm). Preparative reverse phase HPLC was conducted on a Waters 600
system using Waters Nova-Pak C18 (6 μm, 60 Å) or Biotage KP-C18-
HS cartridges. NMR spectra were determined with Bruker ARX 300
MHz, Varian Unity 400 MHz, or Varian Unity INOVA 500 MHz
spectrometers. Chemical shifts are reported in parts per million (ppm)
relative to tetramethylsilane internal standard. Mass spectral (MS) ESI
data were determined on a Thermo-Finnigan SSQ7000 instrument.
Analytical LC-MS was performed on an Agilent series 1100 HPLC system
equipped with an autosampler and coupled to a Finnegan Thermoquest
atmospheric pressure chemical ionization (APCI) mass spectrometer.
HPLC was performed on a Phenomenex Luna C8(2) column (2.0 mm ꢁ
30 mm, 5 μm, 100 Å) using a linear gradient of 10ꢀ100% MeCN and
0.1% trifluoroacetic acid in water over 3 min at 1.5 mL/min.
(4S)-5-[4-(Benzyloxy)phenyl]-4-(dibenzylamino)-3-oxopentaneni-
trile (2). A solution of sodium bis(trimethylsilyl) amide (1 M in THF,
414 mL) at ꢀ45 °C was treated dropwise with a solution of acetonitrile
(24 mL, 460 mmol) in THF (50 mL), and the mixture was stirred for
15 min at ꢀ45 °C. The resulting solution was added via cannula to a
solution of benzyl (2S)-3-[4-(benzyloxy)phenyl]-2-(dibenzylamino)
propanoate (prepared as described previously,11 75.7 g, 140 mmol) in
THF (150 mL) at ꢀ45 °C, stirred for 1 h, treated with solid NH4Cl and
warmed to 5 °C, and then quenched with water. The mixture was
partitioned between ethyl acetate and water. The organic phase was
washed with brine and dried over MgSO4, filtered, and concentrated.
1
Precipitation from ethanol gave 2 (39 g, 60% yield). H NMR (300
MHz, CDCl3) δ ppm 2.92 (dd, J = 13.60, 3.31 Hz, 1 H) 3.04 (d, J = 19.49
Hz, 1 H) 3.14 (dd, J = 13.60, 9.56 Hz, 1 H) 3.48 (dd, J = 9.56, 3.68 Hz,
1 H) 3.56 (d, J = 13.60 Hz, 2 H) 3.83 (d, J = 13.6 Hz, 2 H) 3.85 (d, J =
19.49 Hz, 1 H) 5.03 (s, 2 H) 6.83ꢀ6.92 (m, 2 H) 7.01ꢀ7.11 (m, 2 H)
7.24ꢀ7.46 (m, 15 H). MS (ESI) m/z 475 (M + H)+.
’ CONCLUSIONS
There remains a need to discover new drugs that are potent
against drug-resistant strains of HIV. Upon the basis of observa-
tions with compound 1, it was hypothesized that compounds
with similar or improved resistance profiles could be designed by
mimicking the interactions of the P3 tertiary hydroxyl side chain
of 1 with compounds bearing P1 side chains capable of forming
hydrogen bonds. The compounds were screened against WT and
resistant strains of HIV. By this approach, several compounds,
such as 13, 24, and 29, were identified that demonstrated similar
or improved potencies compared to 1 against highly mutated
strains of HIV derived from patients who previously failed HIV
PI therapy. Overall, compound 13 demonstrated the best balance
of potency against drug-resistant strains of HIV and oral bioavail-
ability in rat pharmacokinetic studies. On the basis of our
observations, modification of the P1 position of this class of
HIV PIs represents a promising approach toward the design of
new drugs with improved resistance profiles.
(2S)-5-Amino-1-[4-(benzyloxy)phenyl]-2-(dibenzylamino)-6-phenyl-
4-hexen-3-one (3). A solution containing 2 (19.0 g, 40.1 mmol) in THF
(48 mL) was treated dropwise with a solution of benzyl magnesium bromide
(120 mL, 1 M in ether) at 0 °C. The mixture was allowed to warm to room
temperature and was stirred for 16 h. The reaction was cooled to 0 °C and
quenched with 10% citric acid, followed by partitioning between ethyl acetate
and water. The organic phase was washed with brine and dried over MgSO4,
filtered, and concentrated to give crude 3 (23.2 g), which was used without
further purification. 1H NMR (300 MHz, CDCl3) δ ppm 2.90 (dd, J = 6.42,
13.59 Hz, 1 H) 3.06 (dd, J = 7.72, 13.98 Hz, 1 H) 3.39ꢀ3.55 (m, 3 H) 3.61
(d, J = 13.97 Hz, 2 H) 3.79 (d, J = 14.34 Hz, 2 H) 4.88 (s, 1 H) 5.00ꢀ5.11
(m, 3 H) 6.80ꢀ6.91 (m, 2 H) 6.96ꢀ7.08 (m, 2 H) 7.14ꢀ7.48 (m, 20 H)
9.80 (s, 1 H). MS (ESI) m/z 567 (M + H)+.
tert-Butyl (1S,3S,4S)-1-Benzyl-5-[4-(benzyloxy)phenyl]-4-(dibenzyl-
amino)-3-hydroxypentylcarbamate (4). Step 1. A suspensionofNaBH4
(6.07 g, 160.4 mmol) in THF (170 mL) at ꢀ10 °C was treated with
methansulfonic acid (26.0 mL, 401.0 mmol) dropwise (Caution: gas
evolution). After complete addition, a solution containing 3 (23.2 g,
40.1 mmol) in a mixture of THF (60 mL) and water (6 mL) was added
and the mixture was stirred at ꢀ10 °C for 18 h.
’ EXPERIMENTAL SECTION
Biological Evaluation. Procedures for EC50 determination against
WT and mutant strains of HIV in MT-4 cells have been reported
previously.10
Step 2. A suspension of NaBH4 (6.07 g, 160.4 mmol) in THF (170 mL)
at 0 °C was treated dropwise with trifluoroacetic acid (15.4 mL, 200.5
mmol) (caution: gas evolution), stirred at 0 °C for 30 min, treated with the
solution from step 1, warmed to room temperature, stirred for 3 h, treated
with a mixture of NaBH4 (6.07 g, 160.4 mmol) and trifluoroacetic acid
(15.4 mL, 200.5 mmol) prepared as described above, warmed to room
temperature, and stirred for 2 h. The reaction was cooled to 0 °C and
quenched cautiously by slow addition of NaOH solution (300 mL, 3 N),
followed by partitioning between tert-butyl methyl ether and water. The
organic phase was washed with NaOH solution (0.5 N), NH4Cl solution,
Pharmacokinetic Evaluation. Compounds were formulated and
dosed in animals as reported previously.9
Chemistry.
General Procedures. Unless otherwise noted, all materials were
obtained from commercial suppliers and used without further purifica-
tion. Anhydrous solvents were obtained from Aldrich (Milwaukee, WI)
and used directly. All reactions involving air- or moisture-sensitive
reagents were performed under a nitrogen or argon atmosphere. All
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and brine, dried over MgSO4, filtered, and concentrated to give the crude
product (22.9 g), which was used without further purification.
4-((2S,3S,5S)-2,5-Bis(tert-butoxycarbonylamino)-3-hydroxy-6-phe-
nylhexyl)phenyl trifluoromethanesulfonate (7). To a room tempera-
ture solution of 5 (1.0 g, 2.50 mmol) in THF (25 mL) were added di-tert-
butyl dicarbonate (0.60 g, 2.75 mmol) and triethylamine (0.70 mL,
5.02 mmol), and the mixture was stirred for 16 h. The solvent was
evaporated, and the residue was dissolved in dichloromethane (10 mL),
followed by the addition of N-phenyl-bis(trifluoromethanesulfonimide)
(1.07 g, 3.00 mmol) and DMAP (0.37 g, 3.03 mmol), and the mixture
was heated to 40 °C for 2 h. The mixture was diluted with ethyl acetate
and washed with 10% citric acid, water, and then brine. The organic was
dried over MgSO4, filtered, and evaporated. The residue was purified by
chromatography on silica gel eluting with 0ꢀ25% ethyl acetate in
Step 3. A solution containing the product from step 2 (22.9 g, 40.1
mmol) in tert-butyl methyl ether (200 mL) was treated with 10% K2CO3
(95 mL) and di-tert-butyl dicarbonate (14.0 g, 64.2 mmol), and stirred at
room temperature for 2 h. The organic phase layer was washed with
water and brine, dried over MgSO4, filtered, and concentrated. The
residue was purified by chromatography on silica gel eluting with 20%
hexanes in chloroform and then with 10% ethyl acetate in chloroform to
give 4 (12.3 g, 46% yield). 1H NMR (300 MHz, CDCl3) δ ppm 1.10ꢀ1.23
(m, 1 H) 1.40 (s, 9 H) 2.51 (dd, J = 14.52, 6.43 Hz, 1 H) 2.61ꢀ2.86 (m, 3
H) 2.98 (dd, J= 14.34, 6.25 Hz, 1 H) 3.36 (d, J= 13.24 Hz, 2 H) 3.54ꢀ3.67
(m, 1 H) 3.73ꢀ3.84 (m, 1 H) 3.88 (d, J = 13.24 Hz, 2 H) 4.37 (s, 1 H) 4.85
(s, 1 H) 5.08 (s, 2 H) 6.83ꢀ6.93 (m, 2 H) 6.96ꢀ7.50 (m, 20 H). MS(ESI)
m/z 671 (M + H)+.
1
dichloromethane to give 7 (0.99 g, 63% yield). H NMR (300 MHz,
DMSO-d6) δ ppm 1.27 (s, 9 H) 1.29 (s, 9 H) 1.42ꢀ1.58 (m, 2 H)
2.52ꢀ2.81 (m, 4 H) 3.47ꢀ3.61 (m, 1 H) 3.68ꢀ3.93 (m, 2 H) 4.58 (d, J =
6.62 Hz, 1 H) 6.29 (d, J = 9.56 Hz, 1 H) 6.63 (d, J = 8.82 Hz, 1 H)
7.09ꢀ7.29 (m, 5 H) 7.31ꢀ7.45 (m, 4 H). MS (APCI) m/z 633 (M + H)+
4-((2S,3S,5S)-5-(tert-Butoxycarbonylamino)-3-hydroxy-2-((S)-2-
(methoxycarbonylamino)-3,3-dimethylbutanamido)-6-phenylhexyl)-
phenyl trifluoromethanesulfonate (8). Following the general proce-
dure for peptide coupling reactions, 5 (12.65 g, 6.62 mmol) was reacted
with (S)-2-(methoxycarbonylamino)-3,3-dimethylbutanoic acid (1.4 g, 7.41
mmol). The crude product was dissolved in dichloromethane (26 mL),
followed by the addition of N-phenyl-bis(trifluoromethanesulfonimide)
(2.84 g, 7.95 mmol) and DMAP (1.00 g, 8.20 mmol), and the mixture
was heated to 40 °C for 2 h. The mixture was diluted with ethyl acetate and
washed with 10% citric acid, water, and then brine. The organic was dried
over MgSO4, filtered, and evaporated. The residue was purified by chroma-
tography on silica gel eluting with 0ꢀ50% ethyl acetate in dichloromethane
to give 8 (3.61 g, 77% yield). 1H NMR (400 MHz, DMSO-d6) δ ppm 0.79
(s, 9 H) 1.27 (s, 9 H) 1.45ꢀ1.57 (m, 2 H) 2.52ꢀ2.65 (m, 2 H) 2.74ꢀ2.84
(m, 2 H) 3.52ꢀ3.63 (m, 1 H) 3.54 (s, 3 H) 3.73ꢀ3.84 (m, 1 H) 3.87 (d, J =
9.65 Hz, 1 H) 4.17ꢀ4.26 (m, 1 H) 4.85 (d, J = 5.10 Hz, 1 H) 6.60 (d, J =
9.00 Hz, 1 H) 6.83 (d, J = 9.65 Hz, 1 H) 7.09ꢀ7.18 (m, 3 H) 7.19ꢀ7.31
(m, 4H) 7.38(d, J=8.57Hz, 2H) 7.52(d,J=9.22Hz, 1H). MS(ESI) m/z
704 (M + H)+.
(4S,5S)-Benzyl 5-((S)-2-(tert-Butoxycarbonylamino)-3-phenylpropyl)-
2,2-dimethyl-4-(4-(trifluoromethylsulfonyloxy)benzyl)oxazolidine-3-
carboxylate (6).
Step 1. A solution containing 4 (12.3 g, 18.4 mmol) in THF (169 mL)
was treated with 10% Pd on carbon (2.5 g) and ammonium formate (6.9
g, 109.4 mmol), and the mixture was heated at reflux for 1.5 h. Additional
10% Pd on carbon (1.25 g) and NH4CO2H (3.45 g) were added, and the
mixture was heated at reflux for 2.5 h. The reaction was concentrated and
partitioned between chloroform and water, and the solution was
adjusted to pH 10 with NaHCO3 solution. The organic phase was
washed with brine and dried over MgSO4, filtered, and concentrated to
give 5 (6.1 g, 82% yield), which was used without further purification.
MS (APCI) m/z 401 (M + H)+.
Step 2. A solution containing 5 (6.1 g, 15.2 mmol) in THF (150 mL)
was treated with N-(benzyloxycarbonyloxy)succinimide (3.4 g, 13.6 mmol)
and N,N-diisopropylethylamine (3.3 mL, 19.0 mmol), stirred at room
temperature for 68 h, and concentrated. The residue was purified by
chromatography on silica gel eluting with 33% ethyl acetate in chloroform
and then with 10% methanol in chloroform to give benzyl (1S,2S,4S)-
4-[(tert-butoxycarbonyl)amino]-2-hydroxy-1-(4-hydroxybenzyl)-5-phenyl-
1
pentylcarbamate (5.1 g, 63% yield). H NMR (300 MHz, DMSO-d6) δ
ppm 1.29 (s, 9 H) 1.40ꢀ1.52 (m, 2 H) 2.52ꢀ2.68 (m, 4 H) 3.50ꢀ3.61 (m,
1 H) 3.71ꢀ3.93 (m, 2 H) 4.53 (d, J = 6.25 Hz, 1 H) 4.80ꢀ5.12 (m, 2 H)
6.55ꢀ6.69 (m, 3 H) 6.74 (d, J=9.19Hz, 1H) 6.94ꢀ7.39 (m, 12 H) 9.09 (s,
1 H). MS (ESI) m/z 535 (M + H)+.
4-((2S,3S,5S)-3-Hydroxy-2,5-bis((S)-2-(methoxycarbonylamino)-3,
3-dimethylbutanamido)-6-phenylhexyl)phenyl trifluoromethanesul-
fonate (9). Compound 7 (0.050 g, 0.079 mmol) was treated with 4 N
HCl in dioxane (0.5 mL) for 0.5 h. The solvent was evaporated, and the
crude product was reacted with tert-butyl (S)-2-(methoxycarbonylamino)-
3,3-dimethylbutanoic acid (0.033 g, 0.175 mmol) following the general
procedure for peptide coupling reactions. The product was purified by
chromatography on silica gel eluting with 0ꢀ100% ethyl acetate in
dichloromethane to provide 9 (0.038 g, 62% yield). 1H NMR (300 MHz,
CDCl3) δ ppm 0.91 (s, 18 H) 1.57ꢀ1.70 (m, 2 H) 2.70ꢀ2.89 (m, 4 H)
3.49ꢀ3.59 (m, 1 H) 3.67 (s, 3 H) 3.68 (s, 3 H) 3.75 (t, J = 9.38 Hz, 2 H)
3.90ꢀ4.01 (m, 1 H) 4.05ꢀ4.20 (m, 2 H) 5.22 (d, J = 9.19 Hz, 1 H) 5.30 (d,
J = 9.19 Hz, 1 H) 5.99 (d, J = 7.72 Hz, 1 H) 6.20 (d, J = 8.82 Hz, 1 H)
7.04ꢀ7.33 (m, 9 H). MS (ESI) m/z 704 (M + H)+.
Step 3. A solution containing the product step 2 (5.1 g, 9.6 mmol) in
dichloromethane (50 mL) was treated with N-phenyl-bis(trifluoro-
methanesulfonimide) (4.1 g, 11.5 mmol) and DMAP (1.4 g, 11.5 mmol),
heated at reflux for 1 h, cooled to room temperature, and purified by
chromatography on silica gel eluting with 0ꢀ50% ethyl acetate in chloroform
to give 4-{(2S,3S,5S)-2-{[(benzyloxy)carbonyl]amino}-5-[(tert-butoxy-
carbonyl)amino]-3-hydroxy-6-phenylhexyl}phenyl trifluoromethanesulfo-
nate (4.7 g, 74% yield). 1H NMR (300 MHz, DMSO-d6) δ ppm 1.29 (s,
9 H) 1.42ꢀ1.58 (m, 2 H) 2.53ꢀ2.65 (m, 2 H) 2.76 (d, J = 6.62 Hz, 2 H)
3.49ꢀ3.66(m, 1H)3.74ꢀ3.97(m, 2H)4.61ꢀ4.75 (m, 1 H) 4.91 (s, 2 H)
6.64 (d, J = 8.82 Hz, 1 H) 6.88 (d, J = 9.19 Hz, 1 H) 7.00ꢀ7.47 (m, 14 H).
MS (ESI) m/z 667 (M + H)+.
Step 4. A solution containing the product from step 3 (4.7 g, 7.1
mmol) in 2,2-dimethoxypropane (70 mL) was treated with p-toluene-
sulfonic acid monohydrate (0.067 g, 0.35 mmol), and the mixture was
stirred at room temperature for 1 h. Triethylamine (0.3 mL, 2.15 mmol)
was added, and the reaction was partitioned between ethyl acetate and
water. The organic phase was washed with brine and dried over MgSO4,
filtered, and concentrated to give 6 (4.83 g, 97% yield), which was used
without further purification. 1H NMR (300 MHz, CDCl3) δ ppm broad
1.39 (s, 9 H) 1.46ꢀ1.67 (m, 7 H) 2.64ꢀ2.80 (m, 2 H) 2.81ꢀ3.12 (m, 2
H) 3.69ꢀ3.88 (m, 2 H) 3.89ꢀ4.05 (m, 1 H) 4.31ꢀ4.52 (m, 1 H)
5.03ꢀ5.31 (m, 2 H) 6.97ꢀ7.15 (m, 6 H) 7.17ꢀ7.29 (m, 4 H)
7.33ꢀ7.44 (m, 4 H). MS (APCI) m/z 707 (M + H)+.
General Procedure for Peptide Coupling Reactions:. Preparation of
Methyl (1S,4S,5S,7S,10S)-7-Benzyl-1,10-ditert-butyl-5-hydroxy-2,9,12-
trioxo-4-[4-(2-pyridinyl)benzyl]-13-oxa-3,8,11-triazatetradec-1-ylcar-
bamate (10) A solution of methyl (S)-1-((2S,3S,5S)-5-amino-3-hydroxy-
6-phenyl-1-(4-(pyridin-2-yl)phenyl)hexan-2-ylamino)-3,3-dimethyl-1-ox-
obutan-2-ylcarbamate (prepared as described previously,9 0.025 g, 0.047
mmol) in THF (0.5 mL) was treated with the (S)-2-(methoxycarbonyl-
amino)-3,3-dimethylbutanoic acid (0.010 g, 0.053 mmol), DEPBT (0.020
g, 0.067 mmol), and N,N-diisopropylethylamine (0.040 mL, 0.229 mmol),
stirred at room temperature for 16 h, and partitioned between ethyl acetate
and 10% Na2CO3 solution. The organic phase was washed with additional
10% Na2CO3 solution and brine, dried over MgSO4, filtered, and
concentrated. The residue was purified by chromatography on silica gel
eluting with 0ꢀ100% ethyl acetate in dichloromethane to give 10 (0.015 g,
7100
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Journal of Medicinal Chemistry
ARTICLE
45% yield). 1H NMR (300 MHz, DMSO-d6) δ ppm 0.77 (s, 9 H) 0.83 (s,
9 H) 1.40ꢀ1.61 (m, 2 H) 2.66ꢀ2.81 (m, 3 H) 3.50 (s, 3 H) 3.54 (s, 3 H)
3.60ꢀ3.68 (m, 1 H) 3.79 (d, J = 9.19 Hz, 1 H) 3.93 (d, J = 9.56 Hz, 1 H)
4.01ꢀ4.18 (m, 2 H) 4.85 (d, J = 5.88 Hz, 1 H) 6.60 (d, J = 9.93 Hz, 1 H)
6.75(d, J=9.93Hz, 1H)7.06ꢀ7.19 (m, 5 H) 7.26ꢀ7.37(m, 3H)7.59 (d,
J = 9.19 Hz, 1 H) 7.74 (d, J = 8.82 Hz, 1 H) 7.80ꢀ7.97 (m, 4 H) 8.59ꢀ8.69
(m, 1 H). MS (APCI) m/z 704.3 (M + H)+.
mmol), dichlorobis(triphenylphosphine)palladium(II) (0.010 g, 0.014
mmol), and 2 M Na2CO3 (0.120 mL) in DMF (0.40 mL) was heated to
80 °C for 2 h. After cooling to room temperature, ethyl acetate was added
and solid was removed by filtration through Celite. The filtrate was washed
with 10% Na2CO3 and brine, dried over MgSO4, filtered, and evaporated.
The residue was purified by chromatography on silica gel eluting with 0ꢀ100%
ethyl acetate in dichloromethane to give methyl (S)-1-((2S,3S,5S)-5-(tert-
butoxycarbonylamino)-3-hydroxy-6-phenyl-1-(4-(quinolin-3-yl)phenyl)-
hexan-2-ylamino)-3,3-dimethyl-1-oxobutan-2-ylcarbamate (0.027 g, 56%
General Procedure for Palladium Catalyzed Coupling of 6
with Stannanes and Conversion to Final Products. Prepara-
tion of Methyl (1S,4S,5S,7S,10S)-7-Benzyl-1,10-ditert-butyl-5-hydroxy-
2,9,12-trioxo-4-[4-(3-pyridinyl)benzyl]-13-oxa-3,8,11-triazatetradec-1-
ylcarbamate (11). Step 1. A solution containing 6 (0.200 g, 0.283
mmol) in DMF (3 mL) was treated with LiCl (0.120 g, 2.83 mmol),
dichlorobis(triphenylphosphine)palladium(II) (0.060 g, 0.085 mmol),
and 3-tri-n-butylstannylpyridine (0.200 mL, 0.870 mmol), heated at
100 °C for 16 h, cooled, and partitioned between ethyl acetate and water.
The organic phase was washed with brine and dried over MgSO4,
filtered, and concentrated. The residue was purified by chromatography
on silica gel eluting with 0ꢀ25% ethyl acetate in dichloromethane to give
(4S,5S)-benzyl 5-((S)-2-(tert-butoxycarbonylamino)-3-phenylpropyl)-
2,2-dimethyl-4-(4-(pyridin-3-yl)benzyl)oxazolidine-3-carboxylate (0.130 g,
72% yield). 1H NMR (300 MHz, DMSO-d6) rotamers δ ppm 1.1, 1.19 (2s,
3 H) 1.28 (s, 9 H) 1.40ꢀ1.58 (m, 4 H) 1.57ꢀ1.74 (m, 1 H) 2.53ꢀ2.72 (m,
2 H) 2.90ꢀ3.02 (m, 2 H) 3.54ꢀ3.74 (m, 1 H) 3.72ꢀ3.89 (m, 1 H)
3.99ꢀ4.14 (m, 1 H) 5.08 (s, 2 H) 6.69ꢀ6.83 (m, 1 H) 7.03ꢀ7.27 (m, 8 H)
7.31ꢀ7.44 (m, 4 H) 7.47 (dd, J = 7.91, 4.96 Hz, 1 H) 7.61 (d, J = 8.09 Hz, 2
H) 8.04 (d, J = 8.09 Hz, 1 H) 8.55 (dd, J = 4.78, 1.47 Hz, 1 H) 8.86 (d, J =
2.21 Hz, 1 H). MS (APCI) m/z 636 (M + H)+.
1
yield). H NMR (300 MHz, DMSO-d6) δ ppm 0.85 (s, 9 H) 1.25
(s, 9 H) 1.44ꢀ1.61 (m, 2 H) 2.53ꢀ2.69 (m, 2 H) 2.76ꢀ2.88 (m, 2 H)
3.49 (s, 3 H) 3.58ꢀ3.70 (m, 1 H) 3.71ꢀ3.86 (m, 1 H) 3.94 (d, J = 9.56 Hz,
1 H) 4.12ꢀ4.26 (m, 1 H) 4.82 (d, J = 5.52 Hz, 1 H) 6.58 (d, J = 8.82 Hz,
1H) 6.85(d,J=9.56Hz, 1H) 7.08ꢀ7.28 (m, 5 H) 7.39 (d, J=8.09Hz, 2H)
7.59ꢀ7.80 (m, 5 H) 8.05 (d, J = 8.46 Hz, 2 H) 8.58 (d, J = 1.84 Hz, 1 H)
9.21 (d, J = 2.21 Hz, 1 H). MS (APCI) m/z 683 (M + H)+.
Step 2. The product from step 1 (0.025 g, 0.037 mmol) was dissolved
in 4 N HCl in dioxane (0.5 mL) at room temperature and stirred for
30 min. Methanol was added, and the mixture was evaporated. The
residue was reacted with tert-butyl (S)-2-(methoxycarbonylamino)-3,3-
dimethylbutanoic acid (0.008 g, 0.042 mmol) following the general
procedure for peptide coupling reactions. The product was purified by
chromatography on silica gel, eluting with 0ꢀ100% ethyl acetate in
dichloromethane to provide 20 (0.028 g, quantitative). 1H NMR (300 MHz,
DMSO-d6) δ ppm 0.78 (s, 9 H) 0.84 (s, 9 H) 1.40ꢀ1.65 (m, 2 H)
2.69ꢀ2.86 (m, 3 H) 3.48 (s, 3 H) 3.54 (s, 3 H) 3.61ꢀ3.72 (m, 1 H) 3.80
(d, J = 9.56 Hz, 1 H) 3.95 (d, J = 10.30 Hz, 1 H) 4.06ꢀ4.20 (m, 2 H) 4.87
(d, J = 5.52 Hz, 1 H) 6.62 (d, J = 9.56 Hz, 1 H) 6.80 (d, J = 9.56 Hz, 1 H)
7.03ꢀ7.20 (m, 5 H) 7.37 (d, J = 8.09 Hz, 2 H) 7.56ꢀ7.84 (m, 6 H) 8.05
(d, J = 9.19 Hz, 2 H) 8.59 (d, J = 2.21 Hz, 1 H) 9.21 (d, J = 2.21 Hz,
1 H). MS (APCI) m/z 754.2 (M + H)+.
Methyl (1S,4S,5S,7S,10S)-7-Benzyl-1,10-di-tert-butyl-5-hydroxy-2,9,12-
trioxo-4-[4-(4-pyridinyl)benzyl]-13-oxa-3,8,11-triazatetradec-1-ylcarba-
mate (12). Using the general procedures, 12 was prepared from 6 and
4-tri-n-butylstannylpyridine. 1H NMR(300 MHz, DMSO-d6) δ ppm 0.77
(s, 9 H) 0.82 (s, 9 H) 1.39ꢀ1.59 (m, 2 H) 2.66ꢀ2.83 (m, 3 H) 3.49 (s, 3
H) 3.54 (s, 3 H) 3.64 (q, J= 6.74 Hz, 1 H) 3.80 (d, J=9.93Hz, 1H) 3.93(d,
J = 9.56 Hz, 1 H) 4.05ꢀ4.17 (m, 2 H) 4.85 (d, J = 5.52 Hz, 1 H) 6.60 (d,
J = 9.19 Hz, 1 H) 6.76 (d, J = 10.30 Hz, 1 H) 7.05ꢀ7.18 (m, 5 H) 7.33 (d,
J = 8.09 Hz, 2 H) 7.54ꢀ7.68 (m, 5 H) 7.73 (d, J = 9.19 Hz, 1 H) 8.57ꢀ8.65
(m, 2 H). MS (APCI) m/z 704.3 (M + H)+.
Step 2. A solution containing the product from step 1 (0.059 g, 0.093
mmol) in a mixture of methanol (3 mL) and aqueous HCl (1 mL, 1 N)
was stirred at 50 °C for 2 h and concentrated to give benzyl (1S,2S,4S)-4-
amino-2-hydroxy-5-phenyl-1-[4-(3-pyridinyl)benzyl]pentylcarbamate
as the hydrochloride salt, which was used without further purification.
Step 3. A solution containing the product from step 2 (0.093 mmol)
in methanol (2 mL) was treated with Pd(OH)2 on carbon (0.050 g, 20%
Pd by wt) and HCl solution (0.040 mL, 4N in dioxane), stirred under a
hydrogen atmosphere (balloon pressure) at room temperature for 2 h,
filtered through a bed of Celite, rinsedwith methanol, and concentratedto
give (2S,3S,5S)-2,5-diamino-6-phenyl-1-[4-(3-pyridinyl)phenyl]-3-hexa-
nol as the hydrochloride salt, which was used without further purification.
Step 4. A solution containing the product from step 3 (0.093 mmol)
in THF (1 mL) was treated with tert-butyl (S)-2-(methoxycarbonyl-
amino)-3,3-dimethylbutanoic acid (0.040 g, 0.211 mmol), DEPBT (0.085
g, 0.284 mmol), and N,N-diisopropylethylamine (0.175 mL, 1.00 mmol),
stirred at room temperature for 1 h, and partitioned between ethyl acetate
and 10% Na2CO3 solution. The organic phase was washed with additional
10% Na2CO3 solution and brine, dried over MgSO4, filtered, and
concentrated. The residue was purified by chromatography on silica gel
eluting with 0ꢀ100% ethyl acetate in dichloromethane, followed by
Dimethyl (2S,20S)-1,10-((2S,3S,5S)-1-(4-(5-Fluoropyridin-3-yl)phenyl)-
3-hydroxy-6-phenylhexane-2,5-diyl)bis(azanediyl)bis(3,3-dimethyl-
1-oxobutane-2,1-diyl)dicarbamate (13). Using the general procedures,
13 was prepared from 8 and 5-fluoropyridin-3-ylboronic acid. 1H NMR
(300 MHz, DMSO-d6) δ ppm 0.77 (s, 9 H) 0.83 (s, 9 H) 1.39ꢀ1.59 (m,
2 H) 2.67ꢀ2.80 (m, 3 H) 3.48 (s, 3 H) 3.54 (s, 3 H) 3.60ꢀ3.69 (m, 1 H)
3.80 (d, J = 9.93 Hz, 1 H) 3.92 (d, J = 9.56 Hz, 1 H) 4.03ꢀ4.18 (m, 2 H)
4.86 (d, J = 5.88 Hz, 1 H) 6.62 (d, J = 9.93 Hz, 1 H) 6.78 (d, J = 9.93 Hz,
1 H) 7.04ꢀ7.19 (m, 5 H) 7.33 (d, J = 8.09 Hz, 2 H) 7.56ꢀ7.64 (m, 3 H)
7.74 (d, J = 8.46 Hz, 1 H) 7.95ꢀ8.03 (m, 1 H) 8.54 (d, J = 2.94 Hz, 1 H)
8.75 (t, J = 1.65 Hz, 1 H). MS (ESI) m/z 722.2 (M + H)+.
1
0ꢀ5% methanol in ethyl acetate, to give 11 (0.035 g, 55% yield). H
NMR (300 MHz, DMSO-d6) δ ppm 0.77 (s, 9 H) 0.83 (s, 9 H)
1.41ꢀ1.59 (m, 2 H) 2.66ꢀ2.81 (m, 3 H) 3.48 (s, 3 H) 3.54 (s, 3 H)
3.59ꢀ3.71 (m, 1 H) 3.80 (d, J = 10.30 Hz, 1 H) 3.93 (d, J = 9.19 Hz, 1 H)
4.03ꢀ4.19 (m, 2 H) 4.84 (d, J = 5.52 Hz, 1 H) 6.61 (d, J = 9.56 Hz, 1 H)
6.78 (d, J = 8.82 Hz, 1 H) 7.04ꢀ7.19 (m, 5 H) 7.32 (d, J = 8.09 Hz, 2 H)
7.47 (dd, J = 7.72, 5.15 Hz, 1 H) 7.51ꢀ7.62 (m, 3 H) 7.73 (d, J = 8.46 Hz,
1 H) 7.97ꢀ8.05(m, 1 H) 8.54 (dd, J = 4.60, 1.65 Hz, 1 H) 8.84 (d, J = 1.84
Hz, 1 H). MS (ESI) m/z 704.3 (M + H)+.
Dimethyl (2S,20S)-1,10-((2S,3S,5S)-1-(4-(6-Fluoropyridin-3-yl)phenyl)-
3-hydroxy-6-phenylhexane-2,5-diyl)bis(azanediyl)bis(3,3-dimethyl-
1-oxobutane-2,1-diyl)dicarbamate (14). Using the general procedures,
14 was prepared from 7 and 6-fluoropyridin-3-ylboronic acid. 1H NMR
(300 MHz, DMSO-d6) δ ppm 0.77 (s, 9 H) 0.83 (s, 9 H) 1.39ꢀ1.65 (m,
2 H) 2.66ꢀ2.84 (m, 3 H) 3.48 (s, 3 H) 3.54 (s, 3 H) 3.58ꢀ3.68 (m,
1 H) 3.80 (d, J = 9.56 Hz, 1 H) 3.93 (d, J = 9.56 Hz, 1 H) 4.01ꢀ4.18
(m, 2 H) 4.85 (d, J = 5.52 Hz, 1 H) 6.62 (d, J = 9.93 Hz, 1 H) 6.78 (d, J
= 9.19 Hz, 1 H) 7.05ꢀ7.19 (m, 5 H) 7.23ꢀ7.35 (m, 3 H) 7.53 (d, J =
8.09 Hz, 2 H) 7.59 (d, J = 8.82 Hz, 1 H) 7.74 (d, J = 8.82 Hz, 1 H)
8.16ꢀ8.27 (m, 1 H) 8.49 (d, J = 2.57 Hz, 1 H). MS (ESI) m/z 722.2
(M + H)+.
General Procedures for the Coupling of 7, 8, and 9 with
Boronic Acids and Conversion to Final Products. Preparation of
Dimethyl (2S,20S)-1,10-((2S,3S,5S)-3-Hydroxy-6-phenyl-1-(4-(quinolin-3-
yl)phenyl)hexane-2,5-diyl)bis(azanediyl)bis(3,3-dimethyl-1-oxobutane-
2,1-diyl)dicarbamate (20). Step 1. A degassed (nitrogen sparge) mixture
of 8 (0.050 g, 0.071 mmol) and quinolin-3-ylboronic acid (0.020 g, 0.116
7101
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Journal of Medicinal Chemistry
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Dimethyl (2S,20S)-1,10-((2S,3S,5S)-1-(4-(2-Fluoropyridin-4-yl)phenyl)-
3-hydroxy-6-phenylhexane-2,5-diyl)bis(azanediyl)bis(3,3-dimethyl-
1-oxobutane-2,1-diyl)dicarbamate (15). Using the general procedures,
15 was prepared from 8 and 2-fluoropyridin-4-ylboronic acid. 1H NMR
(500 MHz, DMSO-d6) δ ppm 0.77 (s, 9 H) 0.83 (s, 9 H) 1.43ꢀ1.61 (m,
2 H) 2.68ꢀ2.83 (m, 4 H) 3.49 (s, 3 H) 3.54 (s, 3 H) 3.59ꢀ3.67 (m, 1 H)
3.79 (d, J = 9.28 Hz, 1 H) 3.92 (d, J = 9.77 Hz, 1 H) 4.05ꢀ4.17 (m, 2 H)
4.85 (s, 1 H) 6.56 (d, J = 10.25 Hz, 1 H) 6.73 (d, J = 9.77 Hz, 1 H)
7.04ꢀ7.20 (m, 5 H) 7.35 (d, J = 7.81 Hz, 2 H) 7.45 (s, 1 H) 7.58 (d, J =
8.79 Hz, 1 H) 7.63ꢀ7.73 (m, 4 H) 8.28 (d, J = 5.37 Hz, 1 H). MS (ESI)
m/z 722.3 (M + H)+.
9.03 (s, 2 H) 9.11 (s, 1 H). MS (APCI) m/z 705 (M + H)+. MS (ESI)
m/z 705.2 (M + H)+.
Dimethyl (2S,20S)-1,10-((2S,3S,5S)-1-(Biphenyl-4-yl)-3-hydroxy-6-phenyl-
hexane-2,5-diyl)bis(azanediyl)bis(3,3-dimethyl-1-oxobutane-2,1-diyl)dicar-
bamate (21). Using the general procedures, 21 was prepared from 7 and
phenylboronic acid. 1H NMR (300 MHz, DMSO-d6) δ ppm 0.78 (s, 9 H)
0.83 (s, 9 H) 1.38ꢀ1.60 (m, 2 H) 2.66ꢀ2.81 (m, 3 H) 3.49 (s, 3 H) 3.54 (s, 3
H) 3.59ꢀ3.72 (m, 1 H) 3.80 (d, J=9.93Hz, 1H) 3.93(d, J=9.56Hz, 1H)
4.03ꢀ4.20 (m, 2 H) 4.84 (d, J = 5.52 Hz, 1 H) 6.62 (d, J = 9.93 Hz, 1 H)
6.79(d,J= 9.19 Hz, 1 H) 7.04ꢀ7.19 (m, 5 H) 7.25ꢀ7.31 (m, 2 H) 7.34 (d, J=
7.35 Hz, 1 H) 7.40ꢀ7.50 (m, 4 H) 7.55ꢀ7.65 (m, 3 H) 7.74 (d, J=8.46Hz,
1 H). MS (ESI) m/z 703.3 (M + H)+.
Dimethyl (2S,20S)-1,10-((2S,3S,5S)-1-(4-(6-Cyanopyridin-3-yl)phenyl)-
3-hydroxy-6-phenylhexane-2,5-diyl)bis(azanediyl)bis(3,3-dimethyl-
1-oxobutane-2,1-diyl)dicarbamate (16). Using the general procedures,
16 was prepared from 8 and 5-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-
2-yl)picolinonitrile. 1H NMR (300 MHz, DMSO-d6) δ ppm 0.77 (s, 9
H) 0.82 (s, 9 H) 1.39ꢀ1.65 (m, 2 H) 2.65ꢀ2.83 (m, 3 H) 3.47 (s, 3 H)
3.54 (s, 3 H) 3.58ꢀ3.71 (m, 1 H) 3.80 (d, J = 9.93 Hz, 1 H) 3.92 (d, J =
9.56 Hz, 1 H) 4.05ꢀ4.20 (m, 2 H) 4.86 (d, J = 5.52 Hz, 1 H) 6.62 (d, J =
9.19 Hz, 1 H) 6.77 (d, J = 9.56 Hz, 1 H) 7.04ꢀ7.19 (m, 5 H) 7.36 (d, J =
8.09 Hz, 2 H) 7.60 (d, J = 9.93 Hz, 1 H) 7.66 (d, J = 8.09 Hz, 2 H) 7.74
(d, J = 8.09 Hz, 1 H) 8.11 (d, J = 8.46 Hz, 1 H) 8.30 (dd, J = 8.09, 2.21 Hz,
1 H) 9.06 (d, J = 2.21 Hz, 1 H). MS (APCI) m/z 729.3 (M + H)+.
Dimethyl (2S,20S)-1,10-((2S,3S,5S)-3-Hydroxy-1-(4-(6-(hydroxymethyl)
pyridin-3-yl)phenyl)-6-phenylhexane-2,5-diyl)bis(azanediyl)bis(3,3-
dimethyl-1-oxobutane-2,1-diyl)dicarbamate (17). tert-Butyl (2S,3S,5S)-
1-(4-(6-cyanopyridin-3-yl)phenyl)-3-hydroxy-6-phenylhexane-2,5-
diyldicarbamate (0.065 g, 0.111 mmol, prepared from reaction of 7 with
5-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)picolinonitrile using the gen-
eral procedure) was dissolved in dichloromethane and cooled to ꢀ78 °C,
followed by dropwise addition of diisobutylaluminum hydride in hexanes
(1 M, 0.26 mL). After 2 h, a saturated solution of sodium potassium tartrate
was added and the mixture was stirred for 30 min and warmed to room
temperature. The reaction was diluted with ethyl acetate, and the organic was
separated, dried over MgSO4, filtered, and evaporated. The crude aldehyde
was dissolved in methanol (0.25 mL) and treated with excess sodium
borohydride (0.02 g) at room temperature for 1 h. The mixture was
extracted with ethyl acetate and washed with water and brine. The resulting
crude alcohol was converted to 17 by the general procedures. 1H NMR (300
MHz, DMSO-d6) δ ppm 0.77 (s, 9 H) 0.83 (s, 9 H) 1.41ꢀ1.58 (m, 2 H)
2.67ꢀ2.84 (m, 3 H) 3.49 (s, 3 H) 3.54 (s, 3 H) 3.59ꢀ3.70 (m, 1 H) 3.80 (d,
J = 9.56 Hz, 1 H) 3.93 (d, J = 9.19 Hz, 1 H) 4.04ꢀ4.19 (m, 2 H) 4.60 (d, J =
5.88 Hz, 2 H) 4.85 (d, J= 5.52 Hz, 1 H) 5.43 (t, J=5.88Hz, 1H) 6.62(d, J=
9.93 Hz, 1 H) 6.79 (d, J=9.56Hz, 1H) 7.02ꢀ7.17 (m, 5 H) 7.31 (d, J=8.09
Hz, 2 H) 7.53 (d, J=8.09Hz, 3H) 7.59(d,J= 8.82 Hz, 1 H) 7.74 (d, J=8.46
Hz, 1 H) 8.02 (dd, J = 8.09, 2.57 Hz, 1 H) 8.73 (d, J = 2.21 Hz, 1 H). MS
(APCI) m/z 734.1 (M + H)+.
Dimethyl (2S,20S)-1,10-((2S,3S,5S)-3-Hydroxy-1-(30-(hydroxymethyl)-
biphenyl-4-yl)-6-phenylhexane-2,5-diyl)bis(azanediyl)bis(3,3-dimethyl-
1-oxobutane-2,1-diyl)dicarbamate (22). Using the general procedures,
22 was prepared from 7 and 3-(hydroxymethyl)phenylboronic acid. 1H
NMR (300 MHz, DMSO-d6) δ ppm 0.78 (s, 9 H) 0.83 (s, 7 H)
1.38ꢀ1.62 (m, 2 H) 2.67ꢀ2.81 (m, 3 H) 3.50 (s, 3 H) 3.54 (s, 3 H)
3.58ꢀ3.70 (m, 1 H) 3.80 (d, J = 9.93 Hz, 1 H) 3.94 (d, J = 9.56 Hz, 1 H)
4.01ꢀ4.17 (m, 2 H) 4.55 (d, J = 5.52 Hz, 2 H) 4.84 (d, J = 5.52 Hz, 1 H)
5.22 (t, J = 5.70 Hz, 1 H) 6.62 (d, J = 9.19 Hz, 1 H) 6.79 (d, J = 9.93 Hz,
1 H) 7.03ꢀ7.18 (m, 5 H) 7.27 (d, J = 8.09 Hz, 3 H) 7.39 (t, J = 7.54 Hz,
1 H) 7.43ꢀ7.51 (m, 3 H) 7.53ꢀ7.63 (m, 2 H) 7.74 (d, J = 7.72 Hz, 1 H).
MS (ESI) m/z 733.2 (M + H)+.
Dimethyl (2S,20S)-1,10-((2S,3S,5S)-3-Hydroxy-1-(40-(hydroxymethyl)-
biphenyl-4-yl)-6-phenylhexane-2,5-diyl)bis(azanediyl)bis(3,3-dimethyl-
1-oxobutane-2,1-diyl)dicarbamate (23). Using the general procedures,
23 was prepared from 7 and 4-(hydroxymethyl)phenylboronic acid. 1H
NMR (300 MHz, DMSO-d6) δ ppm 0.78 (s, 9 H) 0.83 (s, 9 H)
1.36ꢀ1.62 (m, 2 H) 2.66ꢀ2.79 (m, 3 H) 3.50 (s, 3 H) 3.54 (s, 3 H)
3.60ꢀ3.70 (m, 1 H) 3.80 (d, J = 9.93 Hz, 1 H) 3.94 (d, J = 9.56 Hz, 1 H)
3.98ꢀ4.19 (m, 2 H) 4.52 (d, J = 5.52 Hz, 2 H) 4.84 (d, J = 5.52 Hz, 1 H)
5.19 (t, J = 5.70 Hz, 1 H) 6.62 (d, J = 9.56 Hz, 1 H) 6.80 (d, J = 9.19 Hz,
1 H) 7.01ꢀ7.18 (m, 5 H) 7.26 (d, J = 8.09 Hz, 2 H) 7.38 (d, J = 8.09 Hz,
2 H) 7.47 (d, J = 8.09 Hz, 2 H) 7.53ꢀ7.63 (m, 3 H) 7.74 (d, J = 8.82 Hz,
1 H). MS (APCI) m/z 733.3 (M + H)+.
Dimethyl (2S,20S)-1,10-((2S,3S,5S)-3-Hydroxy-1-(40-(methylcar-
bamoyl)biphenyl-4-yl)-6-phenylhexane-2,5-diyl)bis(azanediyl)bis-
(3,3-dimethyl-1-oxobutane-2,1-diyl)dicarbamate (24). Using the gen-
eral procedures, 24 was prepared from 9 and 4-(methylcarbamoyl)
phenylboronic acid. 1H NMR (300 MHz, CDCl3) δ ppm 0.91 (s, 9 H)
0.94 (s, 9 H) 1.53ꢀ1.72 (m, 2 H) 2.21 (s, 3 H) 2.71ꢀ2.81 (m, 2 H)
2.82ꢀ2.91 (m, 2 H) 3.61 (s, 3 H) 3.67 (s, 3 H) 3.73 (d, J = 9.19 Hz, 1 H)
3.80 (d, J = 9.19 Hz, 1 H) 3.88 (d, J = 3.68 Hz, 1 H) 3.92ꢀ4.04 (m, 1 H)
4.07ꢀ4.19 (m, 1 H) 5.30 (d, J = 8.46 Hz, 2 H) 6.00 (d, J = 7.35 Hz, 1 H)
6.18 (d, J = 8.82 Hz, 1 H) 7.04ꢀ7.09 (m, 2 H) 7.11ꢀ7.29 (m, 5 H)
7.44 (d, J = 8.09 Hz, 2 H) 7.50ꢀ7.60 (m, 4 H). MS (ESI) m/z 760.7
(M + H)+.
Dimethyl (2S,20S)-1,10-((2S,3S,5S)-3-Hydroxy-6-phenyl-1-(4-(pyrazin-
2-yl)phenyl)hexane-2,5-diyl)bis(azanediyl)bis(3,3-dimethyl-1-oxobutane-
2,1-diyl)dicarbamate (18). Using the general procedures, 18 was prepared
from 7 and 2-(tributylstannyl)pyrazine. 1H NMR (300 MHz, CD3OD) δ
ppm 0.84 (s, 9 H) 0.89 (s, 9 H) 1.67 (t, J = 7.17 Hz, 2 H) 2.60 (dd, J = 13.42,
9.01 Hz, 1 H) 2.77ꢀ3.03 (m, 3 H) 3.55 (s, 3 H) 3.65 (s, 3 H) 3.73ꢀ3.83
(m, 2 H) 3.91 (s, 1 H) 4.24ꢀ4.40 (m, 2 H) 7.08ꢀ7.22 (m, 5 H) 7.41 (d, J =
8.46 Hz, 2 H) 7.94 (d, J= 8.09 Hz, 2 H) 8.49 (d, J= 2.57 Hz, 1 H) 8.61ꢀ8.67
(m, 1 H) 9.06 (s, 1 H). MS (APCI) m/z 705.2 (M + H)+.
Dimethyl (2S,20S)-1,10-((2S,3S,5S)-3-Hydroxy-1-(30-(methylcarbamoyl)-
biphenyl-4-yl)-6-phenylhexane-2,5-diyl)bis(azanediyl)bis(3,3-dimethyl-
1-oxobutane-2,1-diyl)dicarbamate (25). Using the general procedures,
25 was prepared from 7 and 3-(methylcarbamoyl)phenylboronic acid.
1H NMR (500 MHz, DMSO-d6) δ ppm 0.78 (s, 9 H) 0.83 (s, 9 H)
1.41ꢀ1.58 (m, 2 H) 2.06 (s, 3 H) 2.67ꢀ2.81 (m, 3 H) 3.50 (s, 3 H) 3.55
(s, 3 H) 3.60ꢀ3.68 (m, 1 H) 3.80 (d, J = 9.77 Hz, 1 H) 3.92 (d, J =
9.77 Hz, 1 H) 4.02ꢀ4.17 (m, 2 H) 4.82 (d, J = 5.49 Hz, 1 H) 6.56 (d, J =
9.77 Hz, 1 H) 6.76 (d, J = 9.77 Hz, 1 H) 7.08 (d, J = 6.71 Hz, 2 H)
7.10ꢀ7.17 (m, 3 H) 7.23ꢀ7.32 (m, 3 H) 7.35 (t, J = 7.93 Hz, 1 H) 7.42
(d, J = 7.93 Hz, 2 H) 7.52 (d, J = 7.93 Hz, 1 H) 7.55 (d, J = 9.16 Hz, 1 H)
7.72 (d, J = 8.54 Hz, 1 H) 7.86 (s, 1 H) 9.97 (s, 1 H). MS (ESI) m/z
760.5 (M + H)+.
Dimethyl (2S,20S)-1,10-((2S,3S,5S)-3-Hydroxy-6-phenyl-1-(4-(pyri-
midin-5-yl)phenyl)hexane-2,5-diyl)bis(azanediyl)bis(3,3-dimethyl-
1-oxobutane-2,1-diyl)dicarbamate (19). Using the general procedures,
19 was prepared from 7 and pyrimidin-5-ylboronic acid. 1H NMR (300
MHz, CD3OD) δ ppm 0.85 (s, 9 H) 0.89 (s, 9 H) 1.67 (t, J = 6.99 Hz,
2 H) 2.61 (dd, J = 13.42, 9.01 Hz, 1 H) 2.79ꢀ2.98 (m, 3 H) 3.54 (s, 3 H)
3.65 (s, 3 H) 3.73ꢀ3.84 (m, 2 H) 3.91 (s, 1 H) 4.24ꢀ4.37 (m, 2 H)
7.09ꢀ7.25 (m, 5 H) 7.43 (d, J = 8.09 Hz, 2 H) 7.56 (d, J = 8.09 Hz, 2 H)
Dimethyl (2S,20S)-1,10-((2S,3S,5S)-1-(40-Acetylbiphenyl-4-yl)-3-hy-
droxy-6-phenylhexane-2,5-diyl)bis(azanediyl)bis(3,3-dimethyl-1-oxo-
butane-2,1-diyl)dicarbamate (26). Using the general procedures, 26
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dx.doi.org/10.1021/jm201109t |J. Med. Chem. 2011, 54, 7094–7104

Journal of Medicinal Chemistry
ARTICLE
1
was prepared from 8 and 4-acetylphenylboronic acid. H NMR (300
MHz, CDCl3) δ ppm 0.91 (s, 9 H) 0.94 (s, 9 H) 1.58ꢀ1.69 (m, 2 H)
2.64 (s, 3 H) 2.73ꢀ2.82 (m, 2 H) 2.89 (d, J = 6.25 Hz, 2 H) 3.60 (s, 3 H)
3.67 (s, 3 H) 3.74 (d, J = 8.82 Hz, 1 H) 3.81 (d, J = 9.19 Hz, 1 H)
3.95ꢀ4.06 (m, 2 H) 4.10ꢀ4.21 (m, 1 H) 5.30 (t, J = 9.56 Hz, 2 H) 6.01
(d, J = 7.35 Hz, 1 H) 6.21 (d, J = 8.82 Hz, 1 H) 7.07 (d, J = 6.62 Hz, 2 H)
7.12ꢀ7.32 (m, 5 H) 7.52 (d, J = 8.09 Hz, 2 H) 7.67 (d, J = 8.46 Hz, 2 H)
8.02 (d, J = 8.46 Hz, 2 H). MS (ESI) m/z 745.6 (M + H)+.
X-ray Crystallographic Analysis. HIV protease was purified and
crystallized in the presence of compounds according to procedures
previously described.17 Data were collected at the Argonne National
Laboratory synchrotron on the IMCA ID17 beamline using a Mar 165
CCD detector. Data were processed using HKL2000. The crystals of 11
belong to the space group P1, with unit cell dimensions a = 59.478 Å, b =
66.512 Å, c = 87.595 Å, α = 110.41, β = 91.49, γ = 93.64. The final
structure of the HIV protease/11 inhibited complex was refined in
REFMAC18 resulting in Rf = 28.52% and R = 23.46% to a resolution of
2.8 Å, and the coordinates have been deposited in the Protein Data Bank.
Dimethyl (2S,20S)-1,10-((2S,3S,5S)-3-Hydroxy-1-(40-methoxybiphe-
nyl-4-yl)-6-phenylhexane-2,5-diyl)bis(azanediyl)bis(3,3-dimethyl-1-oxo-
butane-2,1-diyl)dicarbamate (27). Using the general procedures, 27 was
prepared from 7 and 4-methoxyphenylboronic acid. 1H NMR (500 MHz,
DMSO-d6) δ ppm 0.78 (s, 9 H) 0.83 (s, 9 H) 1.41ꢀ1.56 (m, 2 H) 2.68ꢀ
2.79 (m, 3 H) 3.50 (s, 3 H) 3.54 (s, 3 H) 3.60ꢀ3.67 (m, 1 H) 3.77ꢀ3.82
(m, 4 H) 3.93 (d, J = 9.77 Hz, 1 H) 4.02ꢀ4.15 (m, 2 H) 4.80 (s, 1 H) 6.55
(d, J = 9.77 Hz, 1 H) 6.75 (d, J = 9.77 Hz, 1 H) 6.98ꢀ7.04 (m, 2 H) 7.05ꢀ
7.17 (m, 5 H) 7.24 (d, J=7.93Hz, 2H) 7.42(d,J=7.93Hz, 2H) 7.52ꢀ7.57
(m, 3 H) 7.71 (d, J = 8.54 Hz, 1 H). MS (ESI) m/z 733.4 (M + H)+.
Dimethyl (2S,20S)-1,10-((2S,3S,5S)-3-Hydroxy-1-(40-hydroxybiphe-
nyl-4-yl)-6-phenylhexane-2,5-diyl)bis(azanediyl)bis(3,3-dimethyl-
1-oxobutane-2,1-diyl)dicarbamate (28). Using the general procedures,
’ AUTHOR INFORMATION
Corresponding Author
*Phone: 847-937-7205. E-mail: david.degoey@abbott.com. Ad-
dress: Department R4DL, Building AP9A, Abbott Laboratories,
100 Abbott Park Road, Abbott Park, IL 60064.
Present Addresses
†Institute for Tuberculosis Research, College of Pharmacy,
University of Illinois at Chicago, 833 South Wood Street, Chicago,
Illinois 60612.
1
28 was prepared from 7 and 4-hydroxyphenylboronic acid. H NMR
(500 MHz, DMSO-d6) δ ppm 0.78 (s, 9 H) 0.83 (s, 9 H) 1.41ꢀ1.57 (m,
2 H) 2.66ꢀ2.76 (m, 3 H) 3.50 (s, 3 H) 3.54 (s, 3 H) 3.60ꢀ3.67 (m, 1 H)
3.79 (d, J = 9.16 Hz, 1 H) 3.92 (d, J = 9.77 Hz, 1 H) 4.00ꢀ4.18 (m, 2 H)
4.81 (d, J = 5.49 Hz, 1 H) 6.56 (d, J = 9.16 Hz, 1 H) 6.76 (d, J = 9.77 Hz,
1 H) 6.82 (d, J = 8.54 Hz, 2 H) 7.04ꢀ7.17 (m, 5 H) 7.21 (d, J = 7.93 Hz,
2 H) 7.38 (d, J = 7.93 Hz, 2 H) 7.41 (d, J = 8.54 Hz, 2 H) 7.54 (d, J = 9.16
Hz, 1 H) 7.71 (d, J = 8.54 Hz, 1 H) 9.47 (s, 1 H). MS (ESI) m/z 719.5
(M + H)+.
’ ACKNOWLEDGMENT
X-ray data were collected at beamline 17-ID in the facilities of
the Industrial Macromolecular Crystallography Association Col-
laborative Access Team (IMCA-CAT) at the Advanced Photon
Source. These facilities are supported by the companies of the
Industrial Macromolecular Crystallography Association through
a contract with Illinois Institute of Technology (IIT), executed
through IIT’s Center for Synchrotron Radiation Research and
Instrumentation. Use of the Advanced Photon Source was sup-
ported by the U.S. Department of Energy, Basic Energy Sciences,
Office of Science, under contract no. W-31-109-Eng-38. We thank
Dr. Kennan Marsh of Abbott Laboratories for pharmacokinetic data
and analysis.
Dimethyl (2S,20S)-1,10-((2S,3S,5S)-1-(30-Aminobiphenyl-4-yl)-3-hy-
droxy-6-phenylhexane-2,5-diyl)bis(azanediyl)bis(3,3-dimethyl-1-oxo-
butane-2,1-diyl)dicarbamate (29). Using the general procedures,
dimethyl (2S,20S)-1,10-((2S,3S,5S)-3-hydroxy-1-(30-nitrobiphenyl-4-yl)-
6-phenylhexane-2,5-diyl)bis(azanediyl)bis(3,3-dimethyl-1-oxobutane-2,
1-diyl)dicarbamate was prepared from 8 and 3-nitrophenylboronic acid.
The resulting nitro compound (0.082 g, 0.110 mmol) was dissolved in a
mixture of ethyl acetate (1.0 mL) and methanol (1.0 mL), and palladium
hydroxide (0.020 g) was added followed by stirring under hydrogen
(balloon pressure) for 1 h. The reaction was filtered through Celite, and
the filtrate was evaporated. The residue was purified by chromatography
on silica gel eluting with a 0ꢀ100% ethyl acetate in dichloromethane to
give 29 (0.060 g, 76% yield). 1H NMR (300 MHz, DMSO-d6) δ
ppm 0.78 (s, 9 H) 0.83 (s, 9 H) 1.39ꢀ1.58 (m, 2 H) 2.66ꢀ2.80 (m, 3 H)
3.51 (s, 3 H) 3.54 (s, 3 H) 3.58ꢀ3.69 (m, 1 H) 3.80 (d, J = 9.93 Hz, 1 H)
3.93 (d, J = 9.93 Hz, 1 H) 3.99ꢀ4.18 (m, 2 H) 4.84 (d, J = 5.52 Hz, 1 H)
5.11 (s, 2 H) 6.48ꢀ6.55 (m, 1 H) 6.62 (d, J = 10.30 Hz, 1 H) 6.72 (d, J =
7.72 Hz, 1 H) 6.77ꢀ6.85 (m, 2 H) 7.02ꢀ7.18 (m, 6 H) 7.23 (d, J = 8.09
Hz, 2 H) 7.37 (d, J = 8.09 Hz, 2 H) 7.56 (d, J = 8.82 Hz, 1 H) 7.74 (d, J =
8.82 Hz, 1 H). MS (ESI) m/z 718.3 (M + H)+.
’ ABBREVIATIONS USED
PI, protease inhibitor; HAART, highly active antiretroviral
therapy; LPV, lopinavir; RTV, ritonavir; WT, wild type; HS,
human serum; HLM, human liver microsomes; DEPBT, 3-(di-
ethoxyphosphoryloxy)-1,2,3-benzotriazin-4(3H)-one
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Dimethyl (2S,20S)-1,10-((2S,3S,5S)-1-(40-Aminobiphenyl-4-yl)-3-hy-
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acid. The resulting nitro compound was reduced by the procedure used
for 29 to give 30. 1H NMR (300 MHz, DMSO-d6) δ ppm 0.78 (s, 9 H)
0.84 (s, 9 H) 1.37ꢀ1.62 (m, 2 H) 2.65ꢀ2.80 (m, 3 H) 3.51 (s, 3 H) 3.54
(s, 3 H) 3.58ꢀ3.69 (m, 1 H) 3.80 (d, J = 9.93 Hz, 1 H) 3.93 (d, J = 9.56
Hz, 1 H) 3.96ꢀ4.19 (m, 2 H) 4.82 (d, J = 5.15 Hz, 1 H) 5.15 (s, 2 H)
6.61 (m, 3 H) 6.81 (d, J = 9.56 Hz, 1 H) 7.02ꢀ7.24 (m, 7 H) 7.24ꢀ7.40
(m, 4 H) 7.55 (d, J = 8.82 Hz, 1 H) 7.73 (d, J = 8.46 Hz, 1 H). MS (ESI)
m/z 718.2 (M + H)+.
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ARTICLE
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