Design and Syntheses of 1,6-Naphthalene Derivatives as Selective HCMV Protease Inhibitors

Article abstract of DOI:10.1021/jm030540h

Through high throughput screening of various libraries, substituted styryl naphthalene 6 was identified as an HCMV protease inhibitor. Optimization of various regions of the lead molecule using parallel synthesis resulted in 1,6-substituted naphthalenes 1

Full text of DOI:10.1021/jm030540h

J . Med. Chem. 2004, 47, 1893-1899
1893
Articles
Design a n d Syn th eses of 1,6-Na p h th a len e Der iva tives a s Selective HCMV
P r otea se In h ibitor s
Ariamala Gopalsamy,*,† Kitae Lim,† J ohn W. Ellingboe,† Boris Mitsner,† Antonia Nikitenko,† J anis Upeslacis,†
Tarek S. Mansour,† Matthew W. Olson,‡ Geraldine A. Bebernitz,‡ Diane Grinberg,‡ Boris Feld,‡
Franklin J . Moy,† and J ohn O’Connell‡
Chemical and Screening Sciences and Infectious Diseases,Wyeth Research, Pearl River, New York 10965
Received October 23, 2003
Through high throughput screening of various libraries, substituted styryl naphthalene 6 was
identified as an HCMV protease inhibitor. Optimization of various regions of the lead molecule
using parallel synthesis resulted in 1,6-substituted naphthalenes 19d -i. These compounds
displayed good potency and were selective over elastase, trypsin, and chymotrypsin. The
optimization approach on lead compound 6 in three different regions of the molecule using
parallel solution-phase synthesis and the corresponding SAR are discussed in detail.
In tr od u ction
Human cytomegalovirus (HCMV), a member of the
betaherpesvirinae family, infects ∼60% of the popula-
tion in the developed world and >90% of the population
in the developing world.1 However, the physiological and
clinical relevance of this virus is underscored by its
ability to establish lifelong latent infections. Immuno-
compromised/immunosupressed patients are at risk for
disease2 wherein reactivation of the virus produces
clinical manifestations that include pneumonitis, re-
tinitis, colitis, and oesophagitis. The current treatment3
for HCMV includes the use of acyclonucleosides and
nucleotides (acyclovir, gancyclovir, cidofovir), phospho-
nate substrate analogues (foscarnet), and antisense
therapy (formvirsen). The first three require adminis-
tration by intravenous injection, and formvirsen re-
quires intraocular injection. Dosing issues combined
with liabilities of viral resistance and toxic side effects4
highlight the need for new drugs that will alleviate
these difficulties.
F igu r e 1. Irreversible inhibitors of HCMV protease.
chemically reactive to the catalytic serine, Ser-132 and/
or, a surface cysteine Cys-161 (Figure 1) acting as
Michael acceptors8 1 and 2 or electrophiles (e.g. â-lactam
inhibitors9 4 and 5, peptidyl trifluromethyl ketones10 3).
HCMV protease, a serine protease, is a viable target
for antiviral chemotherapy because of its critical role
in capsid assembly and viral maturation.5 There is a
high degree of homology between the herpes proteases,
but little homology exists with the mammalian serine
proteases, which support the notion that specific inhibi-
tors of HCMV protease have antiviral activity with
therapeutic benefit.6 This enzyme exists as a dimer, and
the crystal structure of HCMV protease has identified
Ser-132, His-63, and His-157 to be involved in a unique
catalytic triad.7 Inhibitors that have an effect on dimer
and/or force conformational alterations of the enzyme
would be effective inhibitors of viral proliferation. The
most potent inhibitors described in the literature are
Our interest toward identifying a reversible HCMVP
inhibitor started with the high throughput screening of
the various compound libraries. The effort culminated
in the identification of stilbene 6 that binds nonco-
valently and displays competitive inhibition kinetics in
both HPLC end-point and fluorescent rate-based as-
says.11 This compound does not display time-dependent
inhibition kinetics in comparison to the â- and/or trans-
lactam derivatives, or trifluoromethyl ketones.10 Bio-
physical analyses demonstrate the ability of the com-
pound to displace substrate, confirming the competitive
mechanism of action. Further 1D NMR analysis indi-
cated that the compound binds to protease with 1:1
stoichiometry and displaces substrate.13 Stilbene 6 has
an IC50 value of 66 µM and is selective over elastase11
and chymotrypsin12 (>160 µM). This screening hit was
* To whom correspondence should be addressed. Tel: (845) 602-
2841. Fax: (845) 602-3045. E-mail: gopalsa@wyeth.com.
† Chemical and Screening Sciences.
‡ Infectious Diseases.
10.1021/jm030540h CCC: $27.50 © 2004 American Chemical Society
Published on Web 03/12/2004

1894 J ournal of Medicinal Chemistry, 2004, Vol. 47, No. 8
Gopalsamy et al.
Sch em e 2. Synthesis of Sulfonamide Derivativesa
a
Reagents and conditions: (j) FmocCl, NaHCO3; (k) SOCl2/
DMF; (l) amines, pyr; (m) 20% piperidine in DMF.
F igu r e 2.
Sch em e 3. Synthesis of Amide Derivativesa
Sch em e 1. Synthesis of Stilbene Derivativesa
a
Reagents and conditions: (n) HgO, AcOH, separate; (o)
(CO)Cl2, toluene; (p) H2, Pd/C.
Sch em e 4. Synthesis of Ether Derivativesa
a
Reagents and conditions: (a) Br2,I2, AcOH, recrystallize, 29%;
(b) HCl, MeOH, 98%; (c) CuCN, 66%; (d) 1 N NaOH, 100%; (e)
(PhO)2PON3, t-BuOH, 33%; (f) RaNi, AcOH, NaH2PO2, 68%; (g)
Wittig salt, TEA, CH2Cl2; (h) TFA-CH2Cl2; (i) electrophiles, TEA,
CH2Cl2.
the basis for further modifications in the three regions
outlined (Figure 2).
Ch em istr y. The stilbene analogues were synthe-
sized14 as shown in Scheme 1 starting from 2-naphthoic
acid. Bromination followed by recrystallization to sepa-
rate the isomers provided the desired bromo compound
7 which was converted to the ester and treated with
CuCN to give the nitrile 8. Hydrolysis followed by
treatment with diphenylphosphoryl azide gave the Boc-
protected amine 9. Reduction of 9 to aldehyde 10
provided a key intermediate for further elaboration
using solution phase Wittig reaction with different
Wittig reagents to optimize region 1 (headpiece). The
Boc group was removed, and the free amine was treated
with various electrophiles in parallel to optimize region
3 (tailpiece).
Compounds with sulfonamide linkers (Region 2) were
synthesized following Scheme 2, while Scheme 3 shows
the synthesis of amide analogues. Ethers were synthe-
sized as shown in Scheme 4, and the reverse ethers were
made in the same fashion starting from the correspond-
ing naphthol. All these modifications were made by
parallel solution-phase synthesis.
a
Reagents and conditions: (q) NaBH4, EtOH; (r) PhOH, Ph3P,
DEAD, THF.
1) showed that the region is very flexible and seemed
to accommodate a number of substituents such as
halogen, methoxy, methyl, or the N,N-dimethylamino
group in the 6-position without loss of potency. While
7-, 8-, and 4- substituents were much less probed, they
did seem to tolerate the chloro group and retained
selectivity for elastase. Attempts to replace the hetroar-
omatic headgroup with phenyl or substituted phenyl
groups (6j-n in Table 1) also showed tolerance, accom-
modating a range of lipophilic substituents such as
chloro, trifluoromethyl, or methoxy in the 3 or 4 position.
Even bulky substituents such as 2-naphthyl retained
potency.
While the headgroup (Region 1) modification signifi-
cantly increased the potency of 6 and showed flexibility,
the modifications on the tailpiece (Region 3) showed
limited promise as shown in Table 2. The lead has
trifluoromethylsulfonamide as the tailpiece and it was
of importance to determine if the acidic NH is necessary
for potency. Replacing it with COOH or NH2 or methy-
lating the NH (6o-q) led to loss of potency. The
sulfonamide was also replaced with amide, urea, or
carbamate, and the analogues were found to be inactive.
Attempts were also made to replace the trifluorometh-
ylsulfonamide group with other sulfonamide groups
Resu lts a n d Discu ssion
Initial efforts to modify the pyridyl headgroup in
stilbenes (Region 1) to quinoline increased the potency
significantly while retaining the selectivity for elastase,
as shown by 6b in Table 1. Further probing by intro-
ducing susbtituents on the quinoline ring (6c-f, Table

Selective HCMV Protease Inhibitors
J ournal of Medicinal Chemistry, 2004, Vol. 47, No. 8 1895
Ta ble 3. Linker (Region 2) Modifications
Ta ble 1. Headpiece (Region 1) Modification to Substituted
Quinoline and Phenyl Groups
HCMVP
IC50 (µM) IC50 (µM)
elastase
HCMVP
IC50 (µM)
compd
R1
compd
linker
CHdCH 3-trifluoromethylphenyl
CHdCH 3-trifluoromethylphenyl H,H
R1
X
6
2-pyridyl
66
9.5
>50
>50
>50
>50
>50
>50
>50
>50
>50
>50
>50
>50
>50
>50
6a a
6a b
19a
19b
19c
19d
19e
19f
19g
19h
19i
O
6.9
6.9
15.3
21.3
15.2
4.8
3.1
2.8
5.1
6.1
6b
6c
6d
6e
6f
6g
6h
6i
2-quinolinyl
6-methyl-2-quinolinyl
6-methoxy-2-quinolinyl
6-(N-dimethylamino)-2-quinolinyl
6-chloro-2-quinolinyl
7-chloro-2-quinolinyl
8-chloro-2-quinolinyl
4-chloro-2-quinolinyl
phenyl
6.3
3.4
3.7
3.2
15.1
3.2
10.5
7.5
4.3
6.5
6.6
15
CH2O
CH2O
CH2O
CH2O
CH2O
CH2O
OCH2
OCH2
OCH2
3-chlorophenyl
4-bromophenyl
3-trifluoromethylphenyl
phenyl
3-chlorophenyl
4-bromophenyl
3-chlorophenyl
3-bromophenyl
3-trifluoromethylphenyl
O
O
O
H,H
H,H
H,H
O
O
O
6j
6k
6l
6m
6n
4-chlorophenyl
3-trifluoromethylphenyl
3-methoxyphenyl
7.4
2-naphthyl
f) as well as reverse naphthyl ethers (19g-i) were found
to be active with the appropriate tailpiece in position.
As observed with the styryl analogues, among the
various headpiece groups made, the unsubstituted or
the halogenated phenyl groups are favored for good
potency. As discussed earlier, an acidic moiety is
preferred for the tail region. Apart from the benzoic acid
tailpiece shown in Table 3, phenylsulfonyl ureas and
trifluoromethylsulfonamides were also active. All these
analogues showed very good selectivity for elastase (>50
µM). Some of the potent compounds of interest 19d -i
were also selective for trypsin (>80 µM) and chymot-
rypsin (>50 µM).
Ta ble 2. Tailpiece (Region 3) Modifications
compd
X
R2
HCMVP IC50 (µM)
Con clu sion s
6f
NHSO2CF3
COOH
NH2
N(CH3)SO2CF3
NHSO2CH3
NHCOCH3
NHCOOPh
NHCONHSO2Ph
NHCONHSO2(4-Cl-Ph)
NHCONHSO2(4-CH3-Ph) 7-Cl
NHCOPh
6-Cl
H
3.2
>50
>50
>50
>50
43
6o
6p
6q
6r
6s
6u
6v
6w
6x
6t
Several naphthalene derivatives were identified as
inhibitors of HCMV protease that bind noncovalently
with single micro molar potency and display competitive
inhibition kinetics in both HPLC end-point and fluo-
rescent rate-based assays. These compounds have time-
independent inhibition kinetics and demonstrate the
ability to displace substrate confirming the competitive,
reversible mechanism of action. Extensive SAR modi-
fications resulted in nonstyryl analogues that are selec-
tive for HCMVP.
7-Cl
6-Cl
6-Cl
6-Cl
6-Cl
7-Cl
7-Cl
>50
6.7
4.7
8.3
7-Cl
7-Cl
7-Cl
>50
17.4
2.7
6y
6z
NHCO(4-COOH-Ph)
NHCH2(4-COOH-Ph)
such as trichloromethylsulfonamide, aliphatic sulfona-
mides, or aromatic sulfonamides without much success.
However, the sulfonyl ureas in the place of trifluorom-
ethylsulfonamide retained the potency (6v-x in Table
2), indicating the need for an acidic proton in this region
of the molecule. Although the carboxylic acid replace-
ment itself was unsuccessful, the analogues with a
benzoic acid moiety attached via an amide or aminom-
ethyl linker (6y,z in Table 2) were found to retain
activity.
Variations on the linker (Region 2) to move away from
the styryl moiety in the initial lead 6 was attempted by
replacing the double bond with an amide 17 or sulfona-
mide 13 linker. However, these analogues were inactive.
Reducing the double bond to give the saturated ana-
logue retained the activity. This observation prompted
us to examine equally flexible linkers such as ethers.
As seen from Table 3 both naphthylmethyl ethers (19a -
Exp er im en ta l Section
Gen er a l P r oced u r es. Melting points were determined in
an open capillary tubes on a Meltemp melting point apparatus
1
and are uncorrected. H NMR spectra were determined with
s Bruker DPX-300 spectrometer at 300 MHz. Chemical shifts
δ are reported in parts per million (δ) relative to residual
chloroform (7.26 ppm), TMS (0 ppm), or dimethyl sulfoxide
(2.49 ppm) as an internal reference with coupling constants
(J ) reported in hertz (Hz). The peak shapes are denoted as
follows: s, singlet; d, doublet; t, triplet; q, quartet; m, multiplet;
br, broad. Electrospray (ES) mass spectra were recorded in
positive or negative mode on a Micromass Platform spectrom-
eter. Electron impact and high-resolution mass spectra were
obtained on a Finnegan MAT-90 spectrometer. Combustion
analysis were obtained using Perkin-Elmer Series II 2400
CHNS/O analyzer. The combustion analysis was conducted on
the free base. Chromatographic purifications were performed
by flash chromatography using Baker 40-µm silica gel. Thin-
layer chromatography (TLC) was performed on Analtech silica
gel GHLF 250 M prescored plates. The terms “concentrated”

1896 J ournal of Medicinal Chemistry, 2004, Vol. 47, No. 8
Gopalsamy et al.
and “evaporated” refer to removal of solvents using a rotary
evaporator at water aspirator pressure with a bath tempera-
ture equal to or less than 60 °C. Unless otherwise noted,
reagents were obtained from commercial sources and were
used without further purification
mmol), and the reaction mixture was warmed to 5 °C over 40
min. To this mixture was added a solution of (5-formylnaph-
thalen-2-yl)carbamic acid tert-butyl ester 10 (1.94 g; 7.15
mmol) in THF dropwise over 20 min at -70 °C. The reaction
mixture was warmed to room temperature and stirred over-
night. The reaction was quenched with addition of saturated
ammonium chloride solution, extracted with ethyl acetate,
washed with water and brine, dried, and concentrated under
reduced pressure. The residue was purified by flash column
chromatography to give 2.5 g of the product. 1H NMR (DMSO-
d6): δ 8.7 (d, J ) 5 Hz, 1H), 8.40 (d, J ) 16 Hz, 1H), 8.3 (d, J
) 10 Hz, 1H), 8.2 (s, 1H), 7.8-7.7 (m, 4H), 7.58 (t, J ) 8 Hz,
1H), 7.48 (dd, J ) 9 Hz; 2.2 Hz, 1H), 7.33-7.4 (m, 2H), 1.5 (s,
9H); Anal. Calcd for C22H22N2O2: C, 76.28; H, 6.40; N, 8.09.
Found: C, 76.59; H, 6.33; N, 7.79.
5-Br om on a p h th a len e-2-ca r boxylic Acid Meth yl Ester
(7). Anhydrous HCl gas was bubbled through 60 mL of
methanol, and to the solution was added 5-bromonaphthalene-
2-carboxylic acid (4.02 g). The mixture was stirred at reflux
for 5 h, and the solvent was removed under reduced pressure.
The solid obtained was washed with hexane and ether several
times and dried. Yield: 3.82 g. mp 72-73 °C; 1H NMR (DMSO-
d6): 3.94 (s, 3H), 7.55 (t, J ) 8 Hz, 1H), 8.04 (d, J ) 10 Hz,
1H), 8.15-8.23 (m, 3H), 8.71 (d, ) 2 Hz, 1H). Anal. Calcd for
C
12H9BrO2: C, 54.37; H, 3.42; N, 0.00. Found: C, 54.01; H,
C,C,C-Tr iflu or o-N-[5-(2-p yr id in -2-ylvin yl)n a p h th a len -
2-yl]m eth a n esu lfon a m id e (6). To a solution of tert-butyl
5-[(E)-2-(2-pyridinyl)ethenyl]-2-naphthylcarbamate 11 (5 mmol)
in dichloromethane was added trifluoroacetic acid (10 mmol),
and the solution was stirred at room temperature for 6 h. The
reaction mixture was concentrated, and the residue was taken
up in ethyl acetate and washed with water and sodium
bicarbonate. The organic layer was dried and concentrated
under reduced pressure and passed through a plug of silica to
give the amine. The amine was used for further reactions
without purification.
The above amine ((34.6 mg; 0.1 mmol) was dissolved in 4
mL of dichloromethane and triethylaime (0.36 mmol). To the
solution was added trifluoromethansulfonyl chloride (0.2
mmol), and the reaction mixture was stirred at room-temper-
ature overnight. The solvent was removed under reduced
pressure, and the residue was purified by HPLC. mp 183-
185 °C; 1H NMR (DMSO-d6): δ 8.64 (dd, J ) 5 Hz; 1 Hz, 1H),
8.45 (d, J ) 16 Hz, 1H), 8.37 (d, J ) 10 Hz, 1H), 7.86-7.94
(m, 3H), 7.76-7.81 (m, 2H), 7.58 (t, J ) 8 Hz, 1H), 7.48 (dd, J
) 9 Hz; 2.2 Hz, 1H), 7.33-7.4 (m, 2H); MS (ESI) m/z 379 (MH);
Anal. Calcd for C18H13F3N2O2S + 0.5 H2O: C, 55.81; H, 3.64;
N, 7.23. Found: C, 56.26; H, 3.24; N, 7.08. HRMS Calcd for
3.36; N, 0.02.
5-Cya n on a p h th a len e-2-ca r boxylic Acid Meth yl Ester
(8). 5-Bromonaphthalene-2-carboxylic acid methyl ester 7 (3,7
g; 14 mmol) was dissolved in DMF (20 mL) and pyridine (2
mL), to the solution was added copper cyanide (1.5 g; 16.7
mmol), and the mixture was heated at 160 °C under nitrogen
for 6 h. The solution was cooled to room temperature and
poured into crushed ice (100 g) and concentrated ammonium
hydroxide (50 mL). The precipitate formed was filtered and
washed with dilute ammonium hydroxide. The solid was
further purified by passing though a plug of silica to give an
off white solid (1.9 g). mp 113-115 °C; 1H NMR (CDCl3): 4.02
(s, 3H), 7.62 (t, J ) 8 Hz, 1H), 8.04 (d, J ) 10 Hz, 1H), 8.2 (d,
J ) 10 Hz, 1H), 8.27-8.29 (m, 2H), 8.82 (d, ) 2 Hz, 1H). Anal.
Calcd for C13H9NO2: C, 73.92; H, 4.29; N, 6.63. Found: C,
74.09; H, 4.25; N, 6.66.
(5-Cya n on a p h th a len -2-yl)ca r ba m ic Acid ter t-Bu tyl Es-
ter (9). 5-Cyanonaphthalene-2-carboxylic acid methyl ester 8
(10.5 g; 49.8 mmol) was dissolved in 80 mL of methanol, 1 N
sodium hydroxide solution (55 mL) was added, and the reaction
was stirred at room-temperature overnight. The solvent was
removed under reduced pressure, and the solid was dissolved
in water and acidified with 1 N hydrochloric acid. The solid
obtained was filtered and washed with water and dried
(yield: 8.3 g). The acid (9.29 g; 47.2 mmol) obtained was stirred
with triethylamine (6.7 mL; 48.2 mmol) in tert-butyl alcohol,
and to this solution was added phosphorazidic acid diphenyl
ester (11.3 mL; 51.8 mmol) dropwise over 30 min. The reaction
mixture was stirred at reflux for 24 h and stirred at room
temperature for additional 2 days. The solvent was concen-
trated and quenched with water, extracted with ethyl acetate,
dried, and passed through a plug of silica to give the product
as a white solid (4.2 g). mp 108-111 °C; 1H NMR (CDCl3):
1.56 (s, 9H), 6.8 (brs, 1H), 7.4-7.56 (m, 2H), 7.8 (d, J ) 10
Hz, 1H), 8.0 (d, J ) 10, Hz, 1H), 8.15 (d, J ) 12 Hz, 1H), 8.2
(s, 1H). Anal. Calcd for C16H16N2O2‚0.20 H2O: C, 70.67; H,
6.08; N, 10.30. Found: C, 70.76; H, 5.78; N, 10.20.
(5-F or m yln a p h th a len -2-yl)ca r ba m ic Acid ter t-Bu tyl
Ester (10). mp 96-98 °C dec. (5-Cyanonaphthalen-2-yl)-
carbamic acid tert-butyl ester 9 (4.01 g; 14.9 mmol) was added
to a mixture of pyridine (43 mL) and acetic acid (21 mL) and
stirred for 30 min. To this solution was added Raney Ni (∼5
g) in portions over 10 min. After the gas evolution subsided,
the mixture was heated to 46 °C for 90 min. The reaction
mixture was cooled to room temperature and passed through
a pad of Celite and washed with pyridine. The solution was
concentrated and diluted with ice-water. A solid precipitated
upon standing, which was filtered and purified by silica flash
column chromatography to give a white solid (yield: 2.71 g).
1H NMR (CDCl3): 1.56 (s, 9H), 7.4 (dd, J ) 12 Hz, J ) 3 Hz,
1H), 7.6 (m, 1H), 7.8 (d, J ) 10 Hz, 1H), 8.0 (d, J ) 10 Hz,
1H), 8.4 (br s, 1H), 9.3 (d, J ) 12 Hz, 1H), 10.4 (s, 1H). Anal.
Calcd for C16H17NO3: C, 70.83; H, 6.32; N, 5.16. Found: C,
71.10; H, 6.35; N, 5.42.
C
18H13F3N2O2S: (M + H) 379.07226, found 379.07228.
Compounds 6b-z were prepared by following the procedure
described for 6 starting from the appropriate amine and the
electrophiles.
C,C,C-Tr iflu or o-N-[5-(2-qu in olin -2-ylvin yl)n a p h th a len -
1
2-yl]m eth a n esu lfon a m id e (6b). mp 143-145 °C; H NMR
(DMSO-d6): δ 8.62 (d, J ) 16 Hz, 1H), 8.51 (d, J ) 11 Hz,
1H), 8.46 (d, J ) 11 Hz, 1H), 8.17 (d, J ) 9 Hz, 1H), 7.97-
8.05 (m, 4H), 7.77-7.83 (m, 2H), 7.64-7.5 (m, 4H); MS (EI)
m/z 428; HRMS Calcd for C22H15F3N2O2S: (M - H) 427.0734,
found 427.07248.
C,C,C-Tr iflu or o-N-{5-[2-(6-m eth yl-qu in olin -2-yl)vin yl]-
n a p h th a len -2-yl}m eth a n esu lfon a m id e (6c). mp 237-240
°C; 1H NMR (DMSO-d6): δ 8.58 (d, J ) 16 Hz, 1H), 8.49 (d, J
) 9 Hz, 1H), 8.35 (d, 8 Hz, 1H), 8.12 (d, J ) 8 Hz, 1H), 7.95-
8.00 (m, 3H), 7.82 (d, 2.2 Hz, 1H), 7.76 (s, 1H), 7.60-7.64 (m,
2H), 7.49-7.54 (m, 2H)0.2.51 (s, 3H); MS (EI) m/z 442; HRMS
Calcd for C23H17F3N2O2S: (M - H) 441.089, found 441.08781.
N-{5-[(Z)-2-Ch lor o-2-(6-m eth oxy-2-qu in olin yl)eth en yl]-
2-n a p h th yl}(tr iflu or o)m eth a n esu lfon a m id e (6d ). 1H NMR
(DMSO-d6): δ 8.60 (d, J ) 16 Hz, 1H), 8.48-8.55 (m, 2H), 8.25
(d, 8 Hz, 1H), 8.10 (d, J ) 8 Hz, 1H), 7.95-8.00 (m, 2H), 7.80-
7.85 (m, 2H), 7.50-7.65 (m, 3H), 4.02 (s, 3H); HRMS Calcd
for C23H16ClF3N2O3S: (M + H) 493.0595, found 493.05796.
N-(5-{(E)-2-[6-(Dim eth yla m in o)-2-qu in olin yl]eth en yl}-
2-n a p h th yl)(tr iflu or o)m eth a n esu lfon a m id e (6e). 1H NMR
(DMSO-d6): δ 8.42 (d, J ) 16 Hz, 1H), 8.32 (s, 1H), 8.05-8.15
(m, 2H), 7.95 (d, 8 Hz, 1H), 7.85 (d, J ) 8 Hz, 1H), 7.68 (d, J
) 8 Hz, 1H), 7.62 (d, J ) 8H, 1H), 7.28-7.48 (m, 4H), 6.95 (d,
J ) 3 Hz, 1H), 3.02 (s, 6H); MS (ESI) m/z 472.1 ((M + H)+);
HRMS Calcd for C24H20F3N3O2S: (M + H) 472.1301, found
472.12879.
ter t-Bu t yl 5-[(E)-2-(2-P yr id in yl)et h en yl]-2-n a p h t h yl-
ca r ba m a te (11). A suspension of triphenyl(2-pyridylmethyl)-
phosphonium chloride hydrochloride (2.8 g; 7.1 mmol) in THF
(40 mL) was cooled to -40 °C under nitrogen. To the suspen-
sion was added sodium bis(trimethylsilyl)amide (3.6 mL; 7.2
N-{5-[2-(6-Ch lor oqu in olin -2-yl)vin yl]n a p h th a len -2-yl}-
C,C,C-tr iflu or om eth a n esu lfon a m id e (6f). mp 238-240 °C;
1H NMR (DMSO-d6): δ 8.63 (d, J ) 16 Hz, 1H), 8.52 (d, J )
9 Hz, 1H), 8.40 (d, 8 Hz, 1H), 8.2 (d, J ) 8 Hz, 1H), 8.13 (s,

Selective HCMV Protease Inhibitors
J ournal of Medicinal Chemistry, 2004, Vol. 47, No. 8 1897
1H), 7.98-8.04 (m, 3H), 7.85 (d, 2.2 Hz, 1H), 7.78 (dd, J )
9H; 2.4 Hz, 1H), 7.63 (t, J ) 7.6 Hz, 1H), 7.52-7.57 (m,
C22H17ClN2O2S‚HCl: C, 59.33; H, 4.07; N, 6.29. Found: C,
59.48; H, 3.93; N, 6.21.
2H); MS (ESI) m/z 463 ([M
+
H]+); Anal. Calcd for
N-{5-[2-(6-Ch lor oqu in olin -2-yl)vin yl]n a p h th a len -2-yl}-
a ceta m id e (6s). mp 213-215 °C; 1H NMR (DMSO-d6): δ 10.22
(s, 1H), 8.62 (d, J ) 16 Hz, 1H), 8.37-8.43 (m, 3H), 8.19 (d, J
) 9 Hz, 1H), 8.13 (d, 12 Hz, 1H), 8.05 (d, J ) 9 Hz, 1H), 7.92
(d, J ) 7 Hz, 1H), 7.86 (d, J ) 9 Hz, 1H), 7.78 (dd, J ) 9 Hz;
3 Hz, 1H), 7.69 (dd, J ) 13 Hz; 6 Hz, 1H), 7.51-7.56 (m, 2H),
2.13 (s, 3H); MS (ESI) m/z 373 ([M + H]+); Anal. Calcd for
C
22H14ClF3N2O2S‚0.75 H2O: C, 55.47; H, 3.28; N, 5.88.
Found: C, 55.46; H, 3.38; N, 5.55.
N-{5-[2-(7-Ch lor oq u in olin -2-yl)-vin yl]n a p h t h a len -2-
yl}-C,C,C-tr iflu or om eth a n esu lfon a m id e (6g). mp 202-204
°C; 1H NMR (DMSO-d6): δ 8.63 (d, J ) 16 Hz, 1H), 8.51 (d, J
) 9 Hz, 1H), 8.46 (d, 8 Hz, 1H), 8.16 (d, J ) 8 Hz, 1H), 7.98-
8.07 (m, 4H), 7.84 (s, 1H), 7.52-7.64 (m, 4H); MS (EI) m/z M+.
462; Anal. Calcd for C22H14ClF3N2O2S: C, 57.09; H, 3.05; N,
6.05. Found: C, 56.92; H, 2.90; N, 5.89.
N-{5-[(E)-2-(8-Ch lor o-2-qu in olin yl)eth en yl]-2-n aph th yl}-
(tr iflu or o)m eth a n esu lfon a m id e (6h ). 1H NMR (DMSO-
d6): δ 8.7 (d, J ) 16 Hz, 1H), 8.50 (d, J ) 9 Hz, 2H), 8.25 (d,
8 Hz, 1H), 8.15 (d, J ) 8 Hz, 1H), 7.92-8.02 (m, 3H), 7.85 (d,
2.2 Hz, 1H), 7.75-7.68 (m, 4H); MS (ESI) m/z 463 (M + H)+);
HRMS Calcd for C22H14ClF3N2O2S: (M + H) 463.0489, found
463.0479.
C
23H17ClN2O‚0.25H2O: C, 74.09; H, 4.60; N, 7.51. Found: C,
73.11; H, 4.40; N, 7.12.
N-{5-[(E)-2-(7-Ch lor oqu in olin -2-yl)eth en yl]-2-n aph th yl}-
ben za m id e (6t). LC/MS m/z 435 (M + H) single component
96% (tR 3.763 min). HRMS Calcd for C28H19ClN2O: (M + H)
435.1259, found 435.12495.
{5-[2-(6-Ch lor oq u in olin -2-yl)vin yl]n a p h t h a len -2-yl}-
ca r ba m ic Acid P h en yl Ester (6u ). mp 165 °C; 1H NMR
(DMSO-d6): δ 10.52 (s, 1H), 8.61 (d, J ) 16 Hz, 1H), 8.45 (d,
J ) 9 Hz, 1H), 8.39 (d, 9 Hz, 1H), 8.19 (d, J ) 9 Hz, 1H), 8.13
(dd, J ) 13 Hz; 2.4 Hz, 1H), 8.04 (d, J ) 9 Hz, 1H), 7.93 (d, J
) 7.2 Hz, 1H), 7.85 (d, J ) 9 Hz, 1H), 7.75 (dt, J ) 9 Hz; 2.4
Hz, 2H), 7.44-7.56 (m, 5H), 7.25-7.28 (m, 3H). MS (ESI) m/z
451 (MH); HRMS Calcd for C28H19ClN2O2: (M - H) 449.1062,
found 449.10599.
N-{5-[(E)-2-(4-Ch lor o-2-qu in olin yl)eth en yl]-2-n aph th yl}-
(tr iflu or o)m eth a n esu lfon a m id e (6i). 1H NMR (DMSO-d6):
δ 8.82 (d, J ) 16 Hz, 1H), 8.6-8.68 (m, 2H), 8.25 (t, 8 Hz, 2H),
8.05 (d, J ) 8 Hz, 2H), 7.96 (dt, J ) 8 Hz, 2.2 Hz, 1H), 7.9 (d,
2.2 Hz, 1H), 7.8 (dt, J ) 8 Hz, 2.2 Hz, 1H), 7.60-7.70 (m,
2H), 7.56 (dd, J ) 8 Hz, 2,2 Hz, 1H); HRMS Calcd for
N-[({5-[(E)-2-(7-Ch lor oqu in olin -2-yl)vin yl]-2-n aph th yl}-
a m in o)ca r bon yl]ben zen esu lfon a m id e (6v). LC/MS m/z
C
22H14ClF3N2O2S: (M + H) 463.0489, found 463.04784.
1,1,1-Tr iflu or o-N-{5-[(E)-2-p h en ylvin yl]-2-n a p h t h yl}-
1
512 (M - H) single component 98% (tR 3.570 min). H NMR
(DMSO-d6): δ 8.70 (s, 1H), 8.58 (dd, J ) 16 Hz, J ) 2.2 Hz,
1H), 8.42 (d, J ) 9 Hz, 1H), 8.21 (d, 9 Hz, 1H), 8.10-8.2 (m,
2H), 8.05 (d, J ) 2.4 Hz, 1H), 8.00 (d, J ) 9 Hz; 1H), 7.75-
7.85 (m, 3H), 7.55-7.68 (m, 3H), 7.35-7.5 (m, 3H). HRMS
Calcd for C28H20ClN3O3S: (M + H) 514.0987, found 514.09801.
4-Ch lor o-N-[({5-[(E)-2-(7-ch lor oqu in olin -2-yl)vin yl]-2-
n aph th yl}am in o)car bon yl]ben zen esu lfon am ide (6w). LC/
MS m/z 548 (M + H) single component 95% (tR 3.793 min). 1H
NMR (DMSO-d6): δ 8.73 (s, 1H), 8.58 (d, J ) 16 Hz, 1H), 8.45
(d, J ) 9 Hz, 1H), 8.21 (d, 9 Hz, 1H), 8.17-8.2 (m, 2H), 8.1
(d, J ) 2.4 Hz, 1H), 8.05 (d, J ) 9 Hz; 1H), 7.75-7.85 (m,
3H), 7.55-7.7 (m, 3H), 7.4-7.5 (m, 3H). HRMS Calcd for
m eth a n esu lfon a m id e (6j). LC/MS m/z 376 (M - H) single
component 98% (tR 3.004 min). 1H NMR (DMSO-d6): δ 8.35
(d, J ) 9 Hz; 1 Hz, 1H), 8.05 (d, J ) 16 Hz, 1H), 7.95 (d, J )
9 Hz, 1H), 7.75-7.82 (m, 2H), 7.68 (s, 1H), 7.5 (t, J ) 7.2 Hz,
1H), 7.00-7.41 (m, 5H), 6.85 (d, J ) 12 Hz, 1H); HRMS Calcd
for C19H14F3NO2S: (M - H) 376.0625, found 376.06193.
N-{5-[(E)-2-(4-Ch lor op h en yl)vin yl]-2-n a p h t h yl}-1,1,1-
tr iflu or om eth a n esu lfon a m id e (6k ). LC/MS m/z 410 (M -
H) single component 100% (tR 4.339 min). HRMS Calcd for
C
19H13ClF3NO2S: (M - H) 410.0235, found 410.02328.
1,1,1-Tr iflu or o-N-(5-{(E)-2-[3-(tr iflu or om eth yl)p h en yl]-
vin yl}-2-n a p h th yl)m eth a n esu lfon a m id e (6l). LC/MS m/z
444 (M - H) single component 96% (tR 4.316 min). HRMS
Calcd for C20H13F6NO2S: (M - H) 444.0498, found 444.04945.
C
28H19Cl2N3O3S: (M + H) 548.0597, found 548.05857.
N-[({5-[(E)-2-(7-Ch lor oqu in olin -2-yl)vin yl]-2-n aph th yl}-
a m in o)ca r bon yl]-4-m eth ylben zen esu lfon a m id e (6x). LC/
MS m/z 528 (M + H) single component 99% (tR 3.689 min).
HRMS Calcd for C29H22ClN3O3S: (M + H) 528.1143, found
528.11275.
1,1,1-Tr iflu or o-N-{5-[(E)-2-(3-m eth oxyp h en yl)vin yl]-2-
n a p h th yl}m eth a n esu lfon a m id e (6m ). LC/MS m/z 406 (M
- H) single component 97% (tR 4.119 min). HRMS Calcd for
C
20H16F3NO3S: (M - H) 406.073, found 406.07214.
4-[({5-[(E)-2-(7-Ch lor oisoq u in olin -3-yl)vin yl]-2-n a p h -
th yl}a m in o)m eth yl]ben zoic a cid (6z). LC/MS m/z 465 (M
+ H) single component 97% (tR 3.484 min). HRMS Calcd for
1,1,1-Tr iflu or o-N-{5-[(E)-2-(1-n a p h th yl)vin yl]-2-n a p h -
th yl}m eth a n esu lfon a m id e (6n ). LC/MS m/z 426 (M - H)
single component 95% (tR 3.205 min). HRMS Calcd for
C
29H21ClN2O2: (M + H) 465.1364, found 465.13588.
C
23H16F3NO2S: (M - H) 426.0781, found 426.07654.
4-{[(5-{(E)-2-[3-(Tr iflu or om eth yl)ph en yl]vin yl}-2-n a p h -
5-[(E)-2-(7-Ch lor oqu in olin -2-yl)eth en yl]n a p h th a len -2-
th yl)a m in o]ca r bon yl}ben zoic Acid (6a b). LC/MS m/z 462
(M + H) single component 88% (tR 4.381 min). HRMS Calcd
for C27H18F3NO3: (M - H) 460.1166, found 460.11646.
(5-Hyd r oxym eth yln a p h th a len -2-yl)ca r ba m ic Acid ter t-
Bu tyl Ester (18). (5-Formylnaphthalen-2-yl)carbamic acid
tert-butyl ester 10 (2.2 g; 8 mmol) in anhydrous ethanol was
treated with sodium borohydride (9.7 mmol) at 0 °C. The
reaction mixture was warmed to room temperature and stirred
for additional 2 h. The reaction mixture was quenched with
water and concentrated, and the residue was extracted with
ethyl acetate. The organic layer was dried and passed through
a plug of silica to give 2.15 g of off-white solid, which was
carried forward without further purification.
Gen er a l P r oced u r e for P r ep er a tion of Com p ou n d s
(19a -i). (5-Hydroxymethylnaphthalen-2-yl)carbamic acid tert-
butyl ester 18 (0.8 g; 2.9 mmol) in anhydrous THF was treated
with triphenylphosphine (847 mg; 3.2 mmol) and diethyl
azodicarboxylate (3.2 mmol), to the mixture was added ap-
propriate phenol (3.2 mmol), and the mixture was stirred at
room temperature for 6 h. The solvent was removed under
reduced pressure, and the residue was purified by passing
through a plug of silica. Following the procedure described for
the synthesis of 6, by reacting with appropriate electrophiles
compounds 19a -i were prepared.
a m in e (6p ). LC/MS m/z 331 (M + H) single component 98%
(tR 2.753 min). 1H NMR (DMSO-d6): δ 8.61 (d, J ) 16 Hz, 1H),
8.45 (d, J ) 9 Hz, 1H), 8.22 (d, 9 Hz, 1H), 8.14 (d, J ) 9 Hz,
1H), 8.08 (dd, J ) 3 Hz, 1H), 8.04 (d, J ) 9 Hz, 1H), 7.69 (d,
J ) 9 Hz, 1H), 7.60-7.64 (m, 2H), 7.47 (d, J ) 16 Hz, 1H),
7.40 (t, J ) 7.7 Hz, 1H), 7.13 (dd, J ) 9 Hz, J ) 2 Hz, 1H),
7.01(d, J ) 2 Hz, 1H). MS (ESI) m/z 451 (MH); HRMS Calcd
for C21H15ClN: (M + H) 331.09966, found 331.09957.
N-{5-[2-(6-Ch lor oq u in olin -2-yl)-vin yl]n a p h t h a len -2-
yl}-C,C,C-tr iflu or o-N-m eth ylm eth a n esu lfon a m id e (6q).
1
mp 181-183 °C; H NMR (DMSO-d6): δ 8.65 (d, J ) 16 Hz,
1H), 8.58 (d, J ) 9 Hz, 1H), 8.42 (d, 8 Hz, 1H), 8.19-8.24 (m,
2H), 8.13-8.14 (m, 2H), 8.05-8.08 (m, 2H), 7.79 (dd, J ) 6
Hz; 2.5 Hz, 1H), 7.68-7.73 (m, 2H), 7.57 (d, J ) 16 Hz, 1H);
MS (ESI) m/z 477 (MH); Anal. Calcd for C23H16ClF3N2O2S: C,
57.93; H, 3.38; N, 5.87. Found: C, 57.57; H, 3.33; N, 5.78.
N-{5-[2-(6-Ch lor oqu in olin -2-yl)vin yl]n a p h th a len -2-yl}-
m et h a n esu lfon a m id e (6r ). mp 256 °C (dec); 1H NMR
(DMSO-d6): δ 10.08 (s, 1H), 8.83 (d, J ) 16 Hz, 1H), 8.63 (d,
J ) 9 Hz, 1H), 8.53 (d, 8 Hz, 1H), 8.40 (d, J ) 8 Hz, 1H), 8.22-
8.25 (m, 2H), 7.90-7.96 (m, 3H), 7.75 (d, J ) 2.4 Hz, 1H),
7.58-7.69 (m, 2H), 7.57 (dd, J ) 16 Hz; 2.4 Hz, 1H), 3.09 (s,
3H); MS (ESI) m/z 407/409 (M - H); Anal. Calcd for

1898 J ournal of Medicinal Chemistry, 2004, Vol. 47, No. 8
Gopalsamy et al.
4-[({5-[(3-Ch lor op h en oxy)m eth yl]-2-n a p h th yl}a m in o)-
ca r bon yl]ben zoic Acid (19a ). LC/MS m/z 432 (M + H) single
Refer en ces
(1) Griffiths, P. D.; Emery, V. C. Cytomegalovirus. In Clinical
Virology; Richman, D. D., Whitley, R. J ., Hayden, F. G., Eds.;
Churchill Livingsont Inc.: Secaucus NJ , 1997; pp 445-470. (b)
Ogilvie, W. W. Non-Nucleoside Inhibitors of the Human Cy-
tomegalovirus. Curr. Med. Chem. Anti-Infective Agents 2002, 1,
177-191.
1
component 98% (tR 3.839 min). H NMR (DMSO-d6): δ 10.65
(s, 1H), 8.54 (d, J ) 2 Hz, 1H), 8.10 (d, J ) 8.6 Hz, 1H), 8.09
(s, 4H), 7.89 (d, J ) 8.6 Hz, 2H), 7.60 (d, J ) 7 Hz, 1H), 7.51
(t, J ) 7.32 Hz, 1H), 7.35 (t, J ) 7.8 Hz, 1H), 7.27 (s, 1H), 7.08
(dd, J ) 8.4 Hz; J ) 2.3 Hz, 1H), 7.06 (d, J ) 7.4 Hz, 1H), 5.57
(s, 2H). HRMS Calcd for C25H18ClNO4: (M - H) 430.0852,
found 430.08479.
(2) Alford, C. A.; Britt, W. J . In Virology; Knipe, D. M., Fields, B.
N., Eds.; Raven; New York, 1990, 1981-2010. (b) DeJ ong, M.
D.; Galasso, G. J .; Gazzard, B.; Griffiths, P. D.; J abs, D. A.; Kern,
E. R.; Spectol, S. A. Summary of the II International Symposium
on Cytomegalovirus. Antiviral Res. 1998, 39, 141-162.
(3) Azad, R. F.; Driver, V. B.; Tanaka, K.; Crooke, R. M.; Anderson,
K. P. Antiviral activity of a phosphorothioate oligonucleotide
complementary to RNA of the human cytomegalovirus major
immediate-early region. Antimicrob. Agents Chemother. 1993,
37, 1945-1954. (b) Mulamba, G. B.; Hu, A.; Azad, R. F.;
Anderson, K. P.; Coen, D. M. Human Cytomegalovirus Mutant
with Sequence-Dependent Resistance to the Phosphorothioate
Oligonucleotide Fomivirsen (ISIS 2922). Antimicrob. Agents
Chemother. 1998, 42, 971-973. (c) Abraham, B.; Lastere, S.;
Reynes, J .; Bibollet-Ruche, F.; Vidal, N.; Segondy, M. Ganciclovir
resistance and UL97 gene mutations in cytomegalovirus blood
isolates from patients with AIDS treated with ganciclovir. J .
Clin. Virol. 1999, 13, 141.
4-[({5-[(4-Br om op h en oxy)m eth yl]-2-n a p h th yl}a m in o)-
ca r bon yl]ben zoic Acid (19b). LC/MS m/z 476 (M + H) single
1
component 97% (tR 3.877 min). H NMR (DMSO-d6): δ 10.65
(s, 1H), 8.53 (d, J ) 2 Hz, 1H), 8.09 (d, J ) 8.6 Hz, 1H), 8.08
(s, 4H), 7.89 (d, J ) 8.6 Hz, 2H), 7.58 (d, J ) 7 Hz, 1H), 7.47-
7.51 (m, 3H), 7.09 (d, J ) 7.4 Hz, 1H), 5.54 (s, 2H). HRMS
Calcd for C19H14F3NO2S: (M + H), found.
4-[({5-[(3-Tr iflu or om eth ylph en oxy)m eth yl]-2-n aph th yl}-
a m in o)ca r bon yl]ben zoic Acid (19c). LC/MS m/z 466 (M +
H) single component 95% (tR 3.891 min). HRMS Calcd for
C
26H18F3NO4: (M - H) 464.11151, found 464.1113.
4-({[5-(P h en oxym et h yl)-2-n a p h t h yl]a m in o}m et h yl)-
ben zoic Acid (19d ). LC/MS m/z 384 (M + H) single compo-
(4) Field, A. K. Human cytomegalovirus: challenges, opportunities
and new drug development. Antiviral Chem. Chemother. 1999,
43, 219. (b) Martinez, A.; Castro, A.; Gil, C.; Perez, C. Recent
strategies in the development of new human cytomegalovirus
inhibitors. Med. Res. Rev. 2001, 21, 227.
(5) Holwerda, B. C. Herpesvirus proteases: targets for novel
antiviral drugs. Antiviral Res. 1997, 35, 1-21.
1
nent 100% (tR 3.23 min). H NMR (DMSO-d6): δ 7.89 (d, J )
8.2 Hz, 2H), 7.80 (d, J ) 9 Hz, 1H), 7.50-7.52 (m, 3H), 7.24-
7.32 (m, 4H), 7.10 (dd, J ) 9 Hz; 2.3 Hz, 1H), 7.04 (d, J ) 9
Hz, 2H), 6.95 (t, J ) 7.2 Hz, 1H), 6.68-6.73 (m, 2H), 5.39 (s,
2H), 4.47 (d, J ) 5.8 Hz, 2H). HRMS Calcd for C25H21NO3:
(M + H) 384.1594, found 384.15883.
(6) Gibson, W.; Welch, A. R.; Hall, M. R. T. Assemblin, a herpes
virus serione maturational proeinase and new molecular target
for antivirals. Perspect. Drug Discovery Des. 1994, 2, 413-426.
(7) Tong, L.; Qian, C.; Massariol, M. J .; Bonneau, P. R.; Cordingley,
M. G.; Lagace, L. A new serine-protease fold revealed by the
crystal structure of human cytomegalovirus protease. Nature
1996, 383, 272-275. (b) Qiu, X.; Culp, J . S.; DiLella, A. G.;
Hellmig, B.; Hoog, S. S.; J anson, C. A.; Smith, W. W.; Abdel-
Meguid, S. S. Unique fold and active site in cytomegalovirus
protease. Nature 1996, 383, 275-279. (c) Chen, P.; Tsuge, H.;
Almassy, R. J .; Gribskov, C. L.; Katoh, S.; Vanderpool, D. L.;
Margosiak, S. A.; Pinko, C.; Matthews, D. A.; Kan, C. C.
Structure of the human cytomegalovirus protease catalytic
domain reveals a novel serine protease fold and catalytic triad.
Cell 1996, 86, 835-843. (d) Tong, L.; Qian, C.; Massariol, M. J .;
Deziel, R.; Yoakim, C.; Lagace, L. Conserved mode of peptido-
mimetic inhibition and substrate recognition of human cytome-
galovirus protease. Nat. Struct. Biol. 1998, 5, 819-826.
(8) Dhanak, D.; Keenan, R. M.; Burton, G.; Kaura, A.; Darcy, M.
G.; Shah, D. H.; Ridgers, L. H.; Breen, A.; Lavery, P.; Tew, D.
G.; West, A.. Benzothiopyran-4-one based reversible inhibitors
of the human cytomegalovirus (HCMV) protease. Bioorg Med
Chem Lett. 1998, 8, 3677-82.
(9) Borthwick, A. D.; Weingarten, G.; Haley, T. M.; Tomaszewski,
M.; Wang, W.; Hu, Z.; Bedard, J .; J in, H.; Yuen, L.; Mansour, T.
S. Design and synthesis of monocyclic beta-lactams as mecha-
nism-based inhibitors of human Cytomegalovirus protease.
Bioorg Med Chem Lett. 1998, 8, 365-70. (b) Borthwick, A. D.;
Angier, S. J .; Crame, A. J .; Exall, A. M.; Haley, T. M.; Hart, G.
J .; Mason, A. M.; Pennell, A. M.; Weingarten, G. G. Design and
synthesis of pyrrolidine-5,5-trans-lactams (5-oxo-hexahydro-
pyrrolo[3,2-b]pyrroles) as novel mechanism-based inhibitors of
human cytomegalovirus protease. 1. The alpha-methyl-trans-
lactam template. J Med Chem. 2000, 43, 4452-64. (c) Borthwick,
A. D.; Crame, A. J .; Ertl, P. F.; Exall, A. M.; Haley, T. M.; Hart,
G. J .; Mason, A. M.; Pennell, A. M,.; Singh, O. M.; Weingarten,
G. G.; Woolven, J . M. Design and synthesis of pyrrolidine-5,5-
trans-lactams (5-oxohexahydropyrrolo[3,2-b]pyrroles) as novel
mechanism-based inhibitors of human cytomegalovirus protease.
2. Potency and chirality. J Med Chem. 2002, 45, 1-18. (d)
Borthwick, A. D.; Exall, A. M.; Haley, T. M.; J ackson, D. L.;
Mason, A. M.; Weingarten, G. G. Pyrrolidine-5,5-trans-lactams
as novel mechanism-based inhibitors of human cytomegalovirus
protease. Part 3: potency and plasma stability. Bioorg Med
Chem Lett. 2002, 12, 1719-22. (e) Ogilvie, W. W.; Yoakim, C.;
Do, F.; Hache, B.; Lagace, L.; Naud, J .; O’Meara, J . A.; Deziel,
R. Synthesis and antiviral activity of monobactams inhibiting
the human cytomegalovirus protease. Bioorg Med Chem. 1999,
7, 1521-31. (f) Borthwick, A. D.; Davies, D. E.; Ertl, A. M.; Exall,
A. M.; Haley, T. M.; Hart, G. J .; J ackson, D. C.; Parry, N. R.;
Patikis, A.; Trivedi, N.; Weingarten, G. G. Design and synthesis
of pyrrolidine-5,5′-trans-lactams (5-oxo-hexahydropyrrolo[3,2-b]-
pyrroles) as novel mechanism-based inhibitors of human cy-
tomegalovirus protease. 4. Antiviral activity and plasma stabil-
ity. J Med Chem. 2003, 46, 4428-4449.
4-[({5-[(3-Ch lor op h en oxy)m eth yl]-2-n a p h th yl}a m in o)-
m eth yl]ben zoic Acid (19e). LC/MS m/z 418 (M + H) single
1
component 99% (tR 3.5 min). H NMR (DMSO-d6): δ 7.89 (d,
J ) 8.2 Hz, 2H), 7.78 (d, J ) 9 Hz, 1H), 7.45-7.50 (m, 3H),
7.22-7.30 (m, 3H), 7.18 (broad s, 1H), 7.10 (dd, J ) 9 Hz, 2.3
Hz, 1H), 7.04 (dt, J ) 9 Hz, J ) 2.3 Hz, 2H), 6.69-6.73 (m,
2H), 5.40 (s, 2H), 4.46 (d, J ) 6 Hz, 2H). HRMS Calcd for
C
25H20ClNO3: (M + H) 418.1205, found 418.11981.
4-[({5-[(4-Br om op h en oxy)m eth yl]-2-n a p h th yl}a m in o)-
m eth yl]ben zoic Acid (19f). LC/MS m/z 462 (M + H) single
component 100% (tR 3.54 min). 1H NMR (DMSO-d6): δ 7.89
(d, J ) 8.2 Hz, 2H), 7.78 (d, J ) 9 Hz, 1H), 7.45-7.52 (m, 4H),
7.22-7.27 (m, 2H), 7.10 (dd, J ) 9 Hz, 2.3 Hz, 1H), 7.04 (d, J
) 9 Hz, 2H), 6.69-6.73 (m, 2H), 5.40 (s, 2H), 4.46 (d, J ) 6
Hz, 2H). HRMS Calcd for C25H20BrNO3: (M + H) 462.0699,
found 462.06942.
4-[({5-[(3-Ch lor ob en zyl)oxy]-2-n a p h t h yl}a m in o)ca r -
bon yl]ben zoic Acid (19g). LC/MS m/z 432 (M + H) single
component 98% (tR 2.91 min).). 1H NMR (DMSO-d6): δ 10.6
(s, 1H), 8.45 (d, J ) 2 Hz, 1H), 8.19 (d, J ) 8.2 Hz, 2H), 8.06
(s, 4H), 7.82 (dd, J ) 9.2 Hz, J ) 2.2 Hz, 1H), 7.63 (s, 1H),
7.55 (d, J ) 8 Hz, 1H), 7.39-7.50 (m, 4H), 6.98 (d, J ) 7.4 Hz,
1H), 5.33 (s, 2H). HRMS Calcd for C25H18ClNO4: (M + H)
432.09972, found 432.09894.
4-[({5-[(3-Br om ob en zyl)oxy]-2-n a p h t h yl}a m in o)ca r -
bon yl]ben zoic Acid (19h ). LC/MS m/z 476 (M + H) single
component 92% (tR 2.95 min). 1H NMR (DMSO-d6): δ 10.60
(s, 1H), 8.45 (d, J ) 2 Hz, 1H), 8.18 (d, J ) 8.6 Hz, 1H), 8.06
(s, 4H), 7.96 (s, 1H), 7.83 (dd, J ) 8.4 Hz, J ) 2.3 Hz, 1H),
7.77 (s, 1H), 7.59 (t, J ) 7.8 Hz, 1H), 7.39-7.44 (m, 3H),
6.98 (d, J ) 7.4 Hz, 1H), 5.32 (s, 2H). HRMS Calcd for
C
25H18BrNO4: (M - H) 474.03464, found 474.03514.
4-{[(5-{[3-(Tr iflu or om et h yl)b en zyl]oxy}-2-n a p h t h yl)-
a m in o]ca r bon yl}ben zoic Acid (19i). LC/MS m/z 466 (M +
H) single component 94% (tR 2.95 min). δ 10.58 (s, 1H), 8.40
(d, J ) 2 Hz, 1H), 8.18 (d, J ) 8.6 Hz, 1H), 8.0 (s, 4H), 7.96 (s,
1H), 7.83 (dd, J ) 8.4 Hz, J ) 2.3 Hz, 1H), 7.77 (s, 1H), 7.59
(t, J ) 7.8 Hz, 1H), 7.39-7.44 (m, 3H), 6.98 (d, J ) 7.4 Hz,
1H), 5.32 (s, 2H). HRMS Calcd for C26H18F3NO4: (M + H)
466.12607, found 466.12538.
Ack n ow led gm en t. We thank Discovery Analytical
Chemistry group at Wyeth Research, Pearl River, NY,
for spectral data, and Ms. Choi-Han Tsang for synthesis
of some of the intermediates.

Selective HCMV Protease Inhibitors
J ournal of Medicinal Chemistry, 2004, Vol. 47, No. 8 1899
(10) Bonneau, P. R.; Grand-Maitre, C.; Greenwood, D. J .; Lagace, L.;
LaPlante, S. R.; Massariol, M. J .; Ogilvie, W. W.; O’Meara, J .
A.; Kawai, S. H. Evidence of a conformational change in the
human cytomegalovirus protease upon binding of peptidyl-
activated carbonyl inhibitors Biochemistry 1997, 36, 12644-52.
(11) HCMVP A144L (125 nM), elastase (Calbiochem)(150 nM), and
trypsin (Worthington) (1 nM) were assayed in a 96-well format
in the presence and absence of compound (DMSO final concen-
tration 1%) in a final volume of 200 µL in the presence of 5 µM
of the fluorescent substrate (Dabcyl-RGVVNASSRLA-Edans
(ANASPEC) for 20 min. The buffer conditions for HCMV P were
50 mM HEPES (pH 7.5), 15% glycerol, and 0.6M Na-citrate,
while elastase and trypsin were assayed in 50 mM HEPES pH
8.0, 25 mM NaCl, and 5% glycerol. The assays were terminated
by the addition of TFA to a final concentration of 0.1% and
incubation at 80 °C for 10 min. Samples (100 µL) were analyzed
by reverse-phase HPLC at 1.5 mL min-1 using a HP 1100 series
coupled to a diode array and fluorescence detector. Substrates
and products were resolved on a 50 × 4.6 mm 5 µM C18 column.
Gradient: 20.5-25% ACN for 1.5 min and 25 to 95% ACN for 1
min. The quantity of substrate cleaved in each assay was derived
from the empirically determined product specific activity. This
value was determined as 2331 ( 89 mAu‚S/nmol.
and 1% DMSO in a final volume of 200 µL. Substrate cleavage
was monitored with a Bio-Tek Kinetics reader EL340i. IC50
values were determined from the reaction rates over a 20 min
in 1 min intervals.
(13) µM of stilbene I was titrated with CMVP at a compound-to-
protein ratio of 10:1, 5:1, 2:1, and 1:1 in 10 mM KPO4, 10%
glycerol, pH 7.5 buffer in D2O. Line-width and intensity change
of the compound resonances was consistent with stoichiometric
binding. Similarly the substrate (DABCLY-Arg-Gly-Val-Val-Asn-
Ala-Ser-Ser-Arg-Leu-Ala-EDANS) was determined to bind stoi-
chiometrically with inactive CMVP R166A. Stilbene I displaces
the binding of the substrate.
(14) Compounds were purified by HPLC and the purity was >90%.
LC Conditions: HP 1100, 23 °C, 10 µL injected; column: YMC-
ODS-A 4.6 × 50 5 µm; gradient A: 0.05% TFA/water, B: 0.05%
TFA/acetonitrile; time 0 and 1 min: 98%A and 2%B; 7 min:
10%A and 90%B; 8 min: 10%A and 90%B; 8.9 min: 98%A and
2%B; post time 1 min; flow rate 2.5 mL/min; detection: 215 and
254 nm, DAD. Semiprep HPLC: Gilson with Unipoint software;
column: Phenomenex C18 Luna 21.6 mm × 60 mm, 5 µM;
solvent A: water (0.02% TFA buffer); solvent B: acetonitrile
(0.02% TFA buffer); solvent gradient: time 0: 5% B; 2.5 min:
5% B; 12 min: 95% B; hold 95% B 3 min; flow rate: 22.5 mL/
min; detection: 215 and 254 nm.
(12) Chymotrypsin (Worthington, 8 nM) was assayed in a 96-well
format using the Diapharma peptide substrate S2586 (80 µM)
in the presence of 50 mM Tris (8.5), 150 mM NaCl, 3 mM CaCl2,
J M030540H