New alkenyldiarylmethanes with enhanced potencies as anti-HIV agents which act as non-nucleoside reverse transcriptase inhibitors

Article abstract of DOI:10.1021/jm9800595

Twenty-two new alkenyldiarylmethanes (ADAMs) were synthesized and evaluated for inhibition of HIV-1 replication. The most potent compound proved to be methyl 3',3'-dichloro-4',4'dimethoxy-5',5'-bis(methoxycarbonyl)- 6,6-diphenyl-5-hexenoate (ADAM II), whi

Full text of DOI:10.1021/jm9800595

2076
J . Med. Chem. 1998, 41, 2076-2089
New Alk en yld ia r ylm eth a n es w ith En h a n ced P oten cies a s An ti-HIV Agen ts
Wh ich Act a s Non -Nu cleosid e Rever se Tr a n scr ip ta se In h ibitor s
Mark Cushman,*,† Agustin Casimiro-Garcia,† Elzbieta Hejchman,† J effrey A. Ruell,† Mingjun Huang,‡
Catherine A. Schaeffer,‡ Karen Williamson,‡ William G. Rice,‡ and Robert W. Buckheit, J r.§
Department of Medicinal Chemistry and Molecular Pharmacology, School of Pharmacy and Pharmacal Sciences, Purdue
University, West Lafayette, Indiana 47907, Laboratory of Antiviral Drug Mechanisms, SAIC Frederick, National Cancer
Institute-Frederick Cancer Research and Development Center, Frederick, Maryland 21702-1201, and Virology Research Group,
Southern Research Institute-Frederick Research Center, Frederick, Maryland 21701
Received J anuary 26, 1998
Twenty-two new alkenyldiarylmethanes (ADAMs) were synthesized and evaluated for inhibition
of HIV-1 replication. The most potent compound proved to be methyl 3′,3′′-dichloro-4′,4′′-
dimethoxy-5′,5′′-bis(methoxycarbonyl)-6,6-diphenyl-5-hexenoate (ADAM II), which displayed
an EC50 of 13 nM for inhibition of the cytopathic effect of HIV-1RF in CEM-SS cells. ADAM II
inhibited HIV-1 reverse transcriptase with an IC50 of 0.3 µM but was inactive as an inhibitor
of HIV-1 attachment/fusion to cells, protease, integrase, and the nucleocapsid protein. Molecular
target-based and cell-based assays revealed that ADAM II acted biologically as a nonnucleoside
reverse transcriptase inhibitor (NNRTI). ADAM II inhibited replication of a wide variety of
laboratory, clinical, and clade-representative isolates of HIV-1 in T cell lines and cultures of
peripheral blood mononuclear cells or monocyte/macrophages. Mutations that conferred
resistance to ADAM II clustered at residues 101, 103, 108, 139, 179, 181, and 188, which line
the nonnucleoside binding pocket of HIV-1 reverse transcriptase. However, HIV-1 NL4-3 strain
expressing a mutation at residue 100 of reverse transcriptase, and an AZT-resistant virus,
displayed increased sensitivity to ADAM II. Thus, ADAM II could serve as an adjunct therapy
to AZT and NNRTIs that select for L100I resistance mutations.
The nonnucleoside HIV-1 reverse transcriptase in-
hibitors (NNRTIs) are a structurally diverse set of
compounds that inhibit the enzyme by an allosteric
mechanism involving binding to a site adjacent to the
deoxyribonucleoside triphosphate binding site.1 Well-
known NNRTIs include hydroxyethoxymethylphenyl-
thiothymine (HEPT),2 tetrahydroimidazobenzodiazepi-
none (TIBO),3 dipyridodiazepinone (nevirapine),4 pyri-
dinone,5 bis(heteroaryl)piperazine (BHAP),6 tert-bu-
tyldimethylsilylspiroaminooxathiole dioxide (TSAO),7
and R-anilinophenylacetamide (R-APA)8 derivatives.
Although the rapid emergence of resistant viral strains
has hampered the clinical development of the NNRTIs
for the treatment of AIDS, several strategies have
emerged for overcoming resistance, including switching
to another NNRTI to which the virus has remained
sensitive, using higher doses of the NNRTI against the
resistant strain,9,10 and employing combinations of
agents which elicit mutations that counteract one
another.11,12 A need remains for additional NNRTIs
having unique patterns of resistance mutations in order
to facilitate the application of these strategies.
binding pocket. The designed compounds were pre-
pared and evaluated as inhibitors of HIV-1 reverse
transcriptase (RT) and for inhibition of the cytopathic
effect of HIV in cell culture. As described below, this
strategy resulted in the development of a very potent
ADAM compound that demonstrated increased potency
against HIV-1 strains having the L100I mutation in the
RT enzyme or having multiple mutations that confer
resistance to AZT. Such a compound would be an
attractive adjunct to therapeutic regimens that include
AZT and/or an NNRTI that loses sensitivity against the
L100I mutation.
Ch em istr y
The design of additional ADAMs has been aided by
the availability of X-ray structures of HIV-1 reverse
transcriptase complexed with nevirapine,15-17 R-APA,17,18
TIBO,19-21 HEPT,17 and BHAP.22 These structures
reveal that in general the NNRTIs assume a similar
“butterfly” shape and bind to the enzyme in a similar
way with considerable overlap, although HEPT appears
to be somewhat of an outlier to the general pattern.17,23
This allows the construction of a hypothetical model of
the binding of ADAM 1 to HIV-1 RT. The model was
constructed by overlapping the structure of ADAM 1
with that of nevirapine (2) in the binding pocket of
HIV-1 RT (Sculpt 2.0, Interactive Simulations, San
Diego, CA). During this process, it was assumed that
the hexenyl side chain of ADAM 1 would point in the
same direction as the cyclopropyl substituent of nevi-
rapine. The nevirapine structure was then removed,
the structure of the protein “frozen”, and the energy of
We recently reported a series of alkenyldiaryl-
methanes (ADAMs) which act as NNRTIs.13,14 The most
potent of these proved to be ADAM 1, which displayed
synergistic anti-HIV-1 activity with AZT. To improve
on the lead provided by ADAM 1, additional compounds
in this series were designed to optimize parameters for
space filling and hydrogen bonding in the NNRTI
† Purdue University.
‡ Antiviral Drug Mechanisms.
§ Virology Research Group.
S0022-2623(98)00059-4 CCC: $15.00 © 1998 American Chemical Society
Published on Web 05/16/1998

New Alkenyldiarylmethanes as Anti-HIV Agents
J ournal of Medicinal Chemistry, 1998, Vol. 41, No. 12 2077
termediate 6. Removal of the protecting group from 6
was accomplished with tetra-n-butylammonium fluoride
in THF, yielding the alcohol 7. Reaction of the alcohol
7 with mesyl chloride in the presence of triethylamine
gave the mesylate 8, which was converted to the azide
9 on treatment with sodium azide in DMF.
To convert 1 into a closely related compound bearing
reactive functionality which might serve to alkylate the
enzyme, the conversion of the alkene moiety to an
epoxide was considered. Reaction of 1 with m-chlorop-
eroxybenzoic acid in methylene chloride afforded the
desired epoxide 12.
A series of dichloro ADAMs 13-27 bearing alkenyl
substituents capable of hydrogen bonding were prepared
using the substituted dichlorobenzophenone 11 as the
starting material. Using the Horner-Emmons reaction,
compound 28 was reacted with NaH at low temperature
for 1 h to produce the corresponding anion, which was
then reacted with ketone 11 to afford, after purification,
ester 13 in good yield. The required reagent 28 was
prepared from diethylphosphonoacetic acid (29) and
2-(trimethylsilyl)ethanol (30). Deprotection of 13 was
carried out with tetra-n-butylammonium fluoride in
THF, affording the carboxylic acid 14 as a colorless
crystalline solid. The methyl ester 15 and tert-butyl
ester 16 were also prepared by the Horner-Emmons
reaction starting from methyl diethylphosphonoacetate
(31) and tert-butyl diethylphosphonoacetate (32), re-
spectively.
the complex minimized while allowing the ligand to
move. This resulted in the hypothetical structure
displayed in Figure 1. Besides being consistent with
the reported structures of NNRTI-enzyme complexes,
this model is also supported by our prior mutagenesis
studies of the ADAM binding site of HIV-1 reverse
transcriptase, in which it was determined that the
resistance mutations to ADAM 1 circumscribe a well-
defined binding pocket.13,14
In Figure 1, ADAM 1 is viewed looking down the
alkenyl side chain with the end of the chain in front.
According to this model, the end of the side chain is
located near Glu 138 and Lys 103. Both of these
residues contain side chains with functional groups
capable of acting as hydrogen bond donors, assuming
protonation of the acid. It might be expected that the
incorporation of functional groups at the end of the
alkenyl chain of the ligand which are capable of acting
as hydrogen bond acceptors might allow favorable
interactions with the adjacent residues. It was decided
to synthesize ADAM analogues incorporating function-
ality at the end of the alkenyl side chain that would be
capable of hydrogen bonding. Congeners of 1 were also
planned in which the effect of alkenyl chain length on
activity could be investigated. Various analogues were
also considered in which the bromines present in 1 were
replaced by chlorines, iodines, and hydrogens.
Considering first the compounds having the same
substitution in the aromatic rings as in 1, compounds
3-7 were prepared from the intermediate benzophenone
10. The methylene and ethylene compounds 3 and 4
were prepared by the Wittig reactions of 10 starting
from methyltriphenylphosphonium bromide and ethyl-
triphenylphosphonium bromide, respectively, using so-
dium bis(trimethylsilyl)amide as the base. The meth-
oxyethylene congener 5 was prepared in a similar
reaction employing methoxymethyl(triphenyl)phospho-
nium bromide. Similarly, reaction of ketone 10 with the
Wittig reagent derived from [3-(tert-butyldiphenylsilyl-
oxy)propyl]triphenylphosphonium bromide afforded in-
The Wittig reaction of the ketone 11 with the ylide
derived from [3-(tert-butyldiphenylsilyloxy)propyl]-
triphenylphosphonium bromide afforded the alkene 17.
Removal of the tert-butyldiphenylsilyl protecting group
was accomplished with tetra-n-butylammonium fluoride
in THF to provide the alcohol 18. Oxidation of 18 under
J ones conditions (CrO3, sulfuric acid, acetone), followed
by extraction with 3 M aqueous sodium hydroxide,

2078 J ournal of Medicinal Chemistry, 1998, Vol. 41, No. 12
Cushman et al.
F igu r e 1. Hypothetical model of ADAM 1 docked in the NNRTI binding site of HIV-1 reverse transcriptase (programmed for
walleyed viewing). The ligand shown in black, while the protein backbone is displayed in blue and the amino acid side chains are
colored brown.
yielded the tricarboxylic acid 27, resulting from oxida-
tion of the primary alcohol in 18 and hydrolysis of the
two ester groups during extraction. On the other hand,
reaction of the alcohol 18 with methanesulfonyl chloride
in dichloromethane, using triethylamine as the base,
afforded the mesylate 19. Reaction of the mesylate 19
with sodium azide in DMF gave the azide 20.
chain, the benzophenone 11 was subjected to a Wittig
reaction with the ylide derived from the reaction of the
phosphonium bromide 33 with sodium bis(trimethylsi-
lyl)amide in THF. This resulted in the formation of the
desired compound 22, now called ADAM II.
The Wittig reaction of the ketone 11 with the ylide
derived from [5-(tert-butyldiphenylsilanyloxy)pentyl]-
triphenylphosphonium bromide29 afforded the alkene
23. Removal of the tert-butyldiphenylsilyl protecting
group was accomplished with tetra-n-butylammonium
fluoride in THF to provide the alcohol 24. An inverse-
addition J ones oxidation was used for the preparation
of 25, which involved the slow addition of a solution of
alcohol 24 in acetone to chromium trioxide-aqueous
sulfuric acid. Compound 22 was hydrolyzed with 10%
potassium hydroxide to provide tricarboxylic acid 26.
The effect of replacement of the methoxycarbonyl and
methyl ether groups by cyclic acetonides could be readily
investigated by evaluating the known alcohol 34, pre-
pared previously from the ketone 36.30 The primary
alcohol was converted to the corresponding bromide 35
with carbon tetrabromide and triphenylphosphine in
acetonitrile.31,32
Various methods were considered for the reduction
of the azide 20 to the amine 21. The usual methods for
conversion of azides to amines involving lithium alu-
minum hydride24 or catalytic hydrogenation25 are obvi-
ously not suitable for accomplishing the conversion of
20 to 21 because of the other functionality in addition
to the azide present in 20. Following a protocol de-
scribed by Brown and Salunkhe,26 compound 20 was
reacted with dichloroborane dimethyl sulfide complex
to produce, after appropriate workup, amine 21 in low
yield (15%). Dichloroborane dimethyl sulfide complex
has been reported to react with olefins, but this process
has been described to be slow and incomplete in the
absence of trichloroborane.27 However, it is likely that
the reactivity of the borane complex with olefins is at
least in part responsible for the poor yield observed in
the conversion of 20 to amine 21. Alternative methods
were then considered in order to reduce 20 to 21 in
acceptable yield. Zwierzak et al. reported the prepara-
tion of amines from azides using a variant of the
Staudinger reaction.28 They reacted organic azides with
trialkyl phosphites, instead of the commonly used
triphenylphosphine, to produce iminophosphorane in-
termediates, which after treatment with hydrogen
chloride afforded the corresponding amine hydrochlo-
rides. The higher reactivity of trialkyl phosphites
toward azides was the main assumption for the modi-
fication. This methodology was considered to be the
most adequate for the conversion of azide 20 to amine
21, since the other reactive functionality present in 21
would not be affected by this method. In fact, the
reaction of azide 20 with triethyl phosphite for 24 h,
followed by hydrolysis of the intermediate iminophos-
phorane with dry hydrogen chloride for 48 h, afforded
the amine 21 as its hydrochloride salt in 86% yield.
To synthesize an ADAM having a terminal methoxy-
carbonyl group at the end of an extended alkenyl side
To determine the importance of the two halogen
atoms for biological activity, congeners of ADAM 1 were
prepared in which the halogens were replaced by iodines
and by hydrogens. The syntheses of these compounds
are outlined in Scheme 1. Treatment of the known
diphenylmethane 3733 with dimethyl sulfate in refluxing
acetone with potassium carbonate as the base resulted
in methylation of both carboxylic acids and both phenols
to afford compound 38, which was oxidized to the
benzophenone 39 with chromium trioxide in acetic

New Alkenyldiarylmethanes as Anti-HIV Agents
J ournal of Medicinal Chemistry, 1998, Vol. 41, No. 12 2079
Sch em e 1a
Ta ble 1. Anti-HIV-1 Activities of ADAMs
XTT assay
compd
RT (IC50 µM)a
EC50 (µM)b
CC50 (µM)c
TId
15
1
3
4
5
7
0.38
>100
26
>100
31.6
94
9.2
138
316
10
NAe
NA
NA
6.0
22
>316
>316
>100
48
>52
>278
9
1.1
12
14
15
16
18
19
20
21
22
24
25
26
27
34
35
40
44
5.6
NA
NA
NA
NA
8.6
NA
0.27
NA
0.013
NA
NA
180
NA
NA
NA
NA
NA
>100
16
25
>100
>100
96
>100
16.8
6.9
2
155
2.0
63
0.3
3.6
41.8
15
31.6
10.2
100.4
>316
>316
18.8
176
2430
>100
>100
>100
>100
>100
3.2
1.7
a
Reagents: (a) Me2SO4, K2CO3, Me2CO, reflux (6 h); (b) CrO3,
Ac2O, 0 °C (1 h) and RT (12 h); (c) (1) n-C6H113PPh3Br, NaN-
(SiMe3)2, THF, 0 °C (30 min), (2) add 39, 23 °C (12 h); (d) HNO3,
Ac2O, RT (12 h); (e) H2, PtO2, EtOAc; (f) (1) NaONO, HCl, H2O,
30 min (0 °C), (2) I2, KI, H2O, RT (30 min); (g) (1) n-C6H13PPh3Br,
NaN(SiMe3)2, THF, 0 °C (30 min), (2) add 43, 23 °C (12 h).
14
>316
11
a
Inhibitory activity vs HIV-1 reverse transcriptase with rCdG
b
as the template primer. The EC50 is the 50% inhibitory concen-
tration for cytopathicity of HIV-1RF in CEM-SS cells. c The CC50
is the 50% cytotoxic concentration for mock-infected CEM cells.
anhydride. Reaction of the ketone present in 39 with
the Wittig reagent derived from n-hexyltriphenylphos-
phonium bromide gave the desired analogue 40, in
which the two bromines present in 1 have been replaced
by hydrogens.
d
The TI is the therapeutic index, which is the CC50 divided by
the EC50.
e NA means there was no observed inhibition of HIV-1
cytopathicity up to the cytotoxic concentration in uninfected cells.
inactive as inhibitors of HIV-1 cytopathicity at concen-
trations up to those resulting in cytotoxicity in unin-
fected cells.
Nitration of 39 with nitric acid in acetic anhydride
afforded the dinitro intermediate 41. The two nitro
groups present in 41 were reduced to amines with
Adam’s catalyst in ethyl acetate to provide the diamino
compound 42. Treatment of the diamine 42 with
nitrous acid resulted in the conversion of both amines
to diazonium groups, which were displaced by iodide in
the presence of potassium iodide and iodine under
aqueous conditions to provide intermediate 43. The
reaction of 43 with the ylide derived from n-hexyltri-
phenylphosphonium bromide afforded the desired ana-
logue 44.
The observed increase in antiviral potency of 22
relative to 1 did not correlate with inhibition of HIV-1
RT with poly(rC)‚oligo(dG) as the template primer, since
1 (IC50 vs RT ) 0.38 µM) was essentially equipotent
with ADAM II (22) (IC50 vs RT ) 0.30 µM) as an enzyme
inhibitor. All of the remaining new compounds display-
ing anti-HIV activity were less potent than 1 as inhibi-
tors of HIV-1 RT with poly(rC)‚oligo(dG) as the template
primer, and some of them were significantly less active.
Examples include compounds 7 (IC50 vs RT ) 31.6 µM),
9 (IC50 vs RT ) 94 µM), and 18 (IC50 vs RT > 100 µM).
Conversely, analogues 12 and 40 inhibit HIV-1 RT with
IC50 values of 5.6 and 3.2 µM, respectively, and are
inactive as inhibitors of HIV-1 cytopathicity. All of
these observations lead to the conclusion that there is
not a strong correlation in this series between inhibition
of RT in cell free systems with poly(rC)‚oligo(dG) as the
template primer and inhibition of the cytopathic effect
of HIV-1RF in CEM-SS cells.
Closely related structural analogues of 1 are revealing
in their inactivity as inhibitors of the cytopathic effect
of HIV-1. Examples include the epoxide 12, the dechlo-
rinated analogue 40, and the diiodo congener 44. These
inactive compounds emphasize the fact that there is a
relatively high degree of structural specificity associated
with the antiviral activity of the compounds in the
series, so that even small changes in structure can
result in complete loss of activity. The inactivity of 40
and 44 emphasize a significant role played by the two
bromine atoms present in 1. In this regard, the dichloro
analogue 45 was reported previously to retain activity,
Biologica l Resu lts a n d Discu ssion
Twenty-two new ADAMs were tested for prevention
of the cytopathic effect of HIV-1RF in CEM-SS cells and
for cytotoxicity in uninfected CEM-SS cells, and the
results are listed in Table 1. In addition, these com-
pounds were tested as inhibitors of HIV-1 reverse
transcriptase, and the resulting IC50 values are also
listed in Table 1. The most potent of the new ADAMs,
as well as the one with the highest therapeutic index,
proved to be ADAM II (22), which displayed an EC50
for prevention of the cytopathic effect of HIV-1RF of 0.013
µM. This represents an approximately 700-fold increase
in potency over the lead compound 1, which was the
most potent ADAM of the previously published series.14
Perhaps more importantly, the therapeutic index in-
creased by a factor of 162. The other new compounds
which were equipotent or more potent than 1 for
prevention of HIV-1 cytopathicity included the primary
alcohol 7 (EC50 ) 6.0 µM), the azide 9 (EC50 ) 1.1 µM),
the primary alcohol 18 (EC50 ) 8.6 µM), and the azide
20 (EC50 ) 0.27 µM). The remaining new ADAMs were

2080 J ournal of Medicinal Chemistry, 1998, Vol. 41, No. 12
Cushman et al.
Ta ble 2. Mechanistic Evaluations
IC50 (µM)
parameter
20
9.9
22
1.9
RT rAdT
rCdG
integrase
protease
nucleocapsid p7 protein
2.0
0.3
a
NI100
NI100
>100c
NI25
>100b
although it was approximately half as potent as 1.14
However, the effect of bromine vs chlorine substitution
is not always consistent. For example, if one considers
the bromo alcohol 7 (EC50 6.0 µM) vs the chloro alcohol
18 (EC50 8.6 µM), they are approximately equipotent as
inhibitors of viral cytopathicity. On the other hand, the
chloro azide 20 (EC50 0.27 µM) is 4 times more potent
than the bromo azide 9 (EC50 1.1 µM). The inactivity
of the diiodo compound 44 as an inhibitor of HIV-1
induced cytopathicity and its lower activity as an
inhibitor of RT (IC50 11 µM) vs that of the corresponding
dibromo compound 1 (IC50 0.38 µM) may reflect a
possible size limitation to activity, since the van der
Waals radius of iodine (2.15 Å) is larger than that of
bromine (1.95 Å).
The effect of replacement of the methoxycarbonyl and
methyl ether groups by cyclic acetonides can be seen
by comparison of the activities of the primary alcohols
18 and 34. While 18 inhibited the cytopathic effect of
HIV-1RF with an EC50 of 8.6, the cyclic acetonide 34 was
inactive. The corresponding primary bromide 35 was
also inactive. The inactivity of 34 vs 18 could be due to
the conformational restriction imposed by the six-
membered ring and/or the increased steric bulk due to
the gem-dimethyl moiety.
NI25
a
NI indicates that no inhibition of activity was observed at the
b
indicated high test concentration. A 30% inhibition of HIV-1
protease was observed at a concentration of 100 µM. c A 17%
inhibition of HIV-1 protease was observed at a concentration of
100 µM.
eliminated the antiviral activity. In addition, 25 did not
show inhibition of HIV-1 RT. Results obtained with the
tricarboxylic acid 26, in which all three ester groups of
ADAM II have been hydrolyzed, are not surprising since
results in our previous series of ADAMs had indicated
that hydrolysis of the esters on the aromatic rings was
detrimental to the biological activity.14 The antiviral
assays of ADAM II were performed in the presence of
fetal calf serum (FCS), and various tests with the
compound in different levels of FCS or time in FCS have
not revealed any instability. These results suggest that
hydrolysis of 22 by esterases present in FCS is unlikely
under the antiviral assay conditions.
To determine whether the antiviral activity of ADAM
II (22) was indeed due to its action as an NNRTI, it
was tested in a number of assays representative of
important events in the replication cycle of HIV-1 (Table
2). These included, in addition to RT inhibition with
poly(rA)‚oligo(dT) and poly(rC)‚oligo(dG) as template
primers, assays for inhibition of HIV-1 attachment/
fusion to target cells and the activities of HIV-1 inte-
grase and protease enzymes. The effect of the com-
pounds on the nucleocapsid protein was also investi-
gated.34 ADAM II (22) demonstrated no significant
effect on attachment/fusion, integrase, protease, or
nucleocapsid protein. However, it inhibited RT with
either poly(rA)‚oligo(dT) or poly(rC)‚oligo(dG) as tem-
plate primers. The greater sensitivity to inhibition with
poly(rC)‚oligo(dG) as the template/primer is character-
istic of the HIV-1-specific nonnucleoside reverse tran-
scriptase inhibitors.3,5,35-38 Interestingly, ADAM 1,
which had an EC50 of 0.38 µM with poly(rC)‚oligo(dG)
as the template primer, did not inhibit the enzyme with
poly(rA)‚oligo(dT) as the template primer.14 Thus, there
exists a clear distinction between the abilities of ADAM
1 and ADAM II (22) to inhibit RT activity with the poly-
(rA)‚oligo(dT) template primer system.
There appears to be an important effect of chain
length of the alkenyl appendage. Both of the active
azides 9 and 20 have a six-atom non-hydrogen chain
length which is identical with the alkenyl chain present
in ADAM 1, and in the most active compound, ADAM
II (22), the seven-atom chain length is only slightly
longer.
The effect of incorporation of hydrogen bonding groups
at the end of the alkenyl chain seems to be variable,
depending on the specific group incorporated and the
length of the chain. For example, the primary alcohol
18 was effective in preventing the cytopathic effect of
HIV-1RF with an EC50 of 8.6 µM, but the corresponding
amine 21 was inactive at 100 µM. Assuming the amine
is protonated at physiological pH, it would be capable
of acting as a hydrogen bond donor but not as a
hydrogen bond acceptor at physiological pH, whereas
the alcohol would be capable of functioning as both. The
most effective compounds for inhibition of viral cyto-
pathicity were ADAM II (22), having a methyl ester at
the terminus of the chain, and the two azides 9 and 20.
Although these compounds do have hydrogen bond
accepting groups at the end of the alkenyl chain, it is
difficult to attribute their greater antiviral activity to a
greater affinity for the enzyme, because they are not
more potent than 1 as enzyme inhibitors, at least with
poly(rC)‚oligo(dG) as the template primer. At this point,
it is not possible to attribute the differences in activity
among 1 and 9, 20, or 22 to any well-defined interaction
with the biological system.
The in vitro IC50 for compound 22 vs HIV-1 reverse
transcriptase with poly(rC)‚oligo(dG) as the template
primer (0.3 µM) is significantly higher than its EC50 for
inhibition of the cytopathic effect of HIV-1RF in CEM-
SS cell culture (13 nM). This difference is not unusual
for the NNRTIs.3,35-37 As discussed elsewhere, this
discrepancy may simply reflect the differences between
the in vitro assay, in which synthetic template/primer
has been added, and the cellular system.36
In addition to the molecular target-based mechanistic
assays, ADAM II (22) was also evaluated in a time
course assay to determine the site of action of the
compound during the early phase of HIV-1 replication.
The profile of inhibition of ADAM II (22) corresponded
The methyl ester groups present in 22 were found to
be essential for antiviral activity in this series. Conver-
sion of ADAM II to the carboxylic acid 25 completely

New Alkenyldiarylmethanes as Anti-HIV Agents
J ournal of Medicinal Chemistry, 1998, Vol. 41, No. 12 2081
Ta ble 3. ADAM II Activity against HIV-1 Laboratory-Adapted
Strains, Lymphocyte-Tropic Clinical Isolates, Clades, and
Monocyte-Tropic Strains of HIV-1
virus isolate
virus type
cell type
EC50 (µM)
HIV-1 RF
HIV-1 IIIB
HIV-1 TEKI
HIV-1 ROJ O
HIV-1
HIV-1
HIV-1
HIV-1
HIV-1
WT-laboratorya
WT-laboratorya
WT-clinicalb
WT-clinicalb
clade A
clade B
clade C
clade D
clade E
CEM-SS
CEM-SS
PBMC
PBMC
PBMC
PBMC
PBMC
PBMC
PBMC
0.91
0.16
2.20
2.28
1.09
0.43
1.04
1.02
0.40
1.70
0.36
0.28
HIV-1
HIV-1 Ba-L
HIV-1 ADA
clade F
monocyte-tropic
monocyte-tropic
PBMC
Mono/Mac
Mono/Mac
a
b
Wild-type laboratory-adapted strain. Wild-type clinical iso-
late.
Ta ble 4. ADAM II Activity against a Biological Panel of
Resistant Isolates in CEM-CC Cells
F igu r e 2. Effect of time of addition on ADAM II (22) activity.
ADAM II (10 µM, solid bars), nevirapine (1 µM, open bars), or
dextran sulfate (100 µg/mL, stippled bars) was added to
cultures of CEM-SS cells infected with HIV-1IIIB at the time
of infection (0 h) or at the indicated time after initiation of
infection. Infection was monitored by measurement of cell-free,
virion-associated p24 in the culture fluid. Quantities of p24
are expressed as the percentage of the levels measued in the
drug-free, HIV-1-infected cultures.
virus isolate
mutation in RT
EC50 (µM)
fold resistance
HIV-1 IIIB
OCa
wild-type
L100I
K101E
K103N
V108I
0.39
0.94
11.9
10.8
>50
15
>50
1.08
>50
8.08
2.4
30
28
TSAO/costb
129/costb
thiazolc
calod
>128
T139I
38
DPSe
3TC
Y181C
M184I
Y188 H
P236L
>128
2.8
cost
>128
to that of an NNRTI (Figure 2), in which antiviral
activity was diminished when the compound was added
to cultures 4 h after initiation of infection. This is
analogous to the effects of nevirapine (NNRTI), but
unlike the action of dextran sulfate, which blocks virus
attachment at the cell surface and loses its effectiveness
within the first half hour after initiation of infection.39
PCR-based analysis confirmed that ADAM II (22)
prevented formation of proviral DNA during the early
phase of infection (data not shown). ADAM II (22) had
no effect on late phase virus production from latently
HIV-1 infected U1 cells induced with TNF-R to produce
virus from integrated proviral DNA (data not shown).
Thus, ADAM II (22) acted biologically to inhibit replica-
tion by preventing reverse transcription.
The scope of the anti-HIV activity of ADAM II (22)
was investigated in a number of laboratory-adapted
strains, lymphocyte-tropic clinical isolates, clade rep-
resentatives, and monocyte-tropic strains of HIV-1.
Likewise, ADAM II (22) was tested for inhibitory
activity against an array of HIV-1 strains containing
mutations in the reverse transcriptase enzyme. The
mutant viruses were obtained either by in vitro biologi-
cal selection in the presence of various NNRTIs or by
site-directed mutagenesis. To preserve continuity of
data across the surfeit of virus strains, a greater amount
of virus (higher MOI) was used in these competitive
studies than was used in the original screening assays.
For this reason, the EC50 was generally about 20-fold
greater in these studies than in the original screen.
Nevertheless, ADAM II (22) retained potent anti-HIV-1
activity against a wide variety of laboratory and clinical
HIV-1 strains in CEM-SS, PBMC, and Mono/Mac cells
(Table 3). Results from studies with the panels of
viruses having defined mutations in reverse tran-
scriptase are listed in Tables 4 and 5. Mutations
conferring resistance to ADAM II (22) clustered within
the amino acid residues comprising the NNRTI binding
HEPTf
21
a
Oxathiin carboxanilide resistant. b Costatolide resistant. c Thi-
azolobenzimidazole resistant. Calanolide resistant. e Diphenyl
d
sulfone resistant. f (Hydroxyethoxy)methyl(phenylthio)thymine re-
sistant.
Ta ble 5. ADAM II Activity against a Site-Directed Panel of
Resistant Isolates in CEM-SS Cells
virus isolate
mutation in RT
EC50 (µM) fold resistance
HIV-1 NL4-3
wild-type
L74V
A98G
L100I
K101E
K103N
V106A
V108I
V179D
1.78
2.23
0.84
<0.16
3.05
NCa
NCa
Sb
NCa
>28
7.13
6.74
28
>50
12.7
12.0
50
Y181C
Y188C
>50
>28
6.07
Sb
10.80
0.27
0.90
4XAZT/L100Ic
4XAZTc
4XAZT/Y181Cc
NCa
>28
>50
a
b
No significant change in sensitivity. Enhanced sensitivity.
c AZT resistant.
pocket.15,18,19,40 Resistance mutations to the NNRTIs
R-APA and BHAP are located close to the bound
inhibitors,18,22 and it therefore seems likely that the
mutations conferring resistance to ADAM II (22) may
also be located close to the bound ligand. The mutations
conferring greater than 10-fold resistance to ADAM II
(22) were located at positions 101, 103, 108, 139, 181,
and 188. In contrast, the L100I mutant was signifi-
cantly more sensitive to ADAM II than the correspond-
ing wild-type virus HIV-1 NL4-3 (Table 5). However,
the L100I mutation conferred slightly decreased sensi-
tivity when introduced into the HIV-1 IIIB strain (Table
4).
The mutations conferring resistance and greater
sensitivity to ADAM II (22) are displayed graphically

2082 J ournal of Medicinal Chemistry, 1998, Vol. 41, No. 12
Cushman et al.
F igu r e 3. The non-nucleoside HIV-1 reverse transcriptase inhibitor (NNRTI) binding site. Mutation of the yellow- and red-
colored residues results in resistance to known NNRTIs. Mutation of the yellow residues also results in resistance to ADAM II
(22), while mutation of the red residue results in increased sensitivity to ADAM II (22).
um bromide (132 mg, 0.36 mmol) was suspended in anhydrous
THF (2 mL), the mixture was stirred under Ar in an ice bath,
and sodium bis(trimethylsilyl)amide (1.0 M in THF, 0.4 mL,
0.4 mmol) was added by syringe. The mixture was stirred for
20 min, and a solution of 1014 (155 mg, 0.3 mmol) in anhydrous
THF (3 mL) was slowly injected. The ice bath was removed,
and the reaction mixture was stirred for 1 h at ambient
temperature and for 1 h at 60 °C overnight at ambient
temperature. The reaction was quenched with saturated
ammonium chloride solution (3 mL). The yellow organic layer
was separated, and the aqueous layer was extracted with
benzene (2 × 5 mL). The combined organic extracts were
washed with brine (2 mL) and dried (Na2SO4). The solvent
was evaporated, and the residue was purified by flash chro-
matography on silica gel (6 g), eluting with hexanes-ethyl
acetate (6:1) to give 3 (62 mg 42%) as a colorless solid: mp
144-145 °C; 1H NMR (CDCl3, 300 MHz) δ 7.70 (m, 2 H), 7.68
(m, 2 H), 5.53 (s, 2 H), 4.01 (s, 3 H), 4.00 (s, 3 H), 3.97 (s, 3 H),
3.96 (s, 3 H); IR (KBr) 2943, 1730, 1472, 1434, 1246, 1208,
1086, 992, 797, 726 cm-1; CIMS m/z (relative intensity) 516
(27), 515 (96), 514 (21), 512 (M+, 5), 486 (10), 485 (45), 484
(21), 483 (100). Anal. (C20H18Br2O6‚1H2O) C, H.
3′,3′′-Dib r om o-4′,4′′-d im et h oxy-5′,5′′-b is(m et h oxyca r -
bon yl)-1,1-d ip h en ylp r op en e (4). Ethyl(triphenyl)phospho-
nium bromide (134 mg, 0.36 mmol) was suspended in anhy-
drous THF (2 mL), and the mixture was stirred under Ar in
an ice bath. Sodium bis(trimethylsilyl)amide (1.0 M in THF,
0.5 mL) was added by syringe. The mixture was stirred for
20 min, and a solution of 10 (155 mg, 0.3 mmol) in anhydrous
THF (3 mL) was slowly injected. The ice bath was removed,
and the reaction mixture was stirred for 24 h at ambient
temperature. The reaction was quenched with saturated
ammonium chloride solution (3 mL). The yellow organic layer
was separated, and the aqueous layer was extracted with
benzene (2 × 5 mL). The combined organic extracts were
washed with brine (2 mL) and dried (Na2SO4). The solvent
was evaporated and the residue purified by flash chromatog-
raphy on silica gel (6 g), eluting with hexanes-ethyl acetate
(6:1), to afford 4 (55 mg, 35%) as a colorless solid: mp 76-77
°C; 1H NMR (CDCl3, 300 MHz) δ 7.54 (m, 2 H), 7.51 (m, 1 H),
7.49 (m, 1 H), 6.18 (q, J ) 7.2 Hz, 1 H), 3.99 (s, 3 H), 3.93 (s,
6 H), 3.92 (s, 3 H), 1.77 (d, J ) 7.2 Hz, 3 H); IR (KBr) 2950,
1732, 1475, 1286, 1263, 1207, 997, 725 cm-1; CIMS m/z (rel
intensity) 531 (62), 530 (29), 529 (94), 528 (23), 527 (M + 1,
57), 500 (12), 499 (53), 498 (24), 497 (100), 495 (53). Anal.
(C21H20Br2O6) C, H.
in Figure 3, which was constructed by erasing nevirap-
ine from the structure of the nevirapine-RT complex.
This shows the amino acid residues in the p66 subunit
surrounding the NNRTI binding pocket.15 Mutation of
the yellow-colored residues in Figure 3 results in
resistance to ADAM II (22), while mutation of the red-
colored residue results in greater sensitivity to ADAM
II (22) in the NL4-3 strain. The mutation at amino acid
residue 139, which results in resistance to ADAM II
(22), is not shown because it is located in the p51
subunit. The cluster of yellow-colored amino acid
residues shown in Figure 3 indicates the geometrical
relationship of the residues that are likely to be involved
in ADAM II (22) binding.
More impressive though was the finding that the
virus containing the L100I mutation and the multiple
mutations that confer resistance to AZT also displayed
increased sensitivity to ADAM II (22). This suggests
the possible clinical utility of ADAM II (22) against AZT
resistant strains of HIV-1 and against strains of HIV-1
that express L100I-based resistance to other NNRTIs.
Ongoing crystallographic studies may lend insight into
the binding interactions of ADAM II (22) with HIV-1
RT, while in vivo toxicology, pharmacology, and efficacy
studies will be required to determine the utility of
ADAM II (22) as a potential clinical candidate. Con-
sistent with this finding, an isolate selected in cell
culture for resistance to OC (oxathiin carboxanilide) and
having an L100I mutation in RT retained sensitivity to
ADAM II (EC50 ) 0.94 µM).
Exp er im en ta l Section
Gen er a l. Melting points were determined in capillary
tubes on a Mel-Temp apparatus and are uncorrected. Spectra
were obtained as follows: CI mass spectra on a Finnegan 4000
spectrometer; FAB mass spectra and EI mass spectra on a
Kratos MS50 spectrometer; 1H NMR spectra on Varian VXR-
500S and Bruker ARX-300 spectrometers; IR spectra on a
Beckman IR-33 spectrometer or on a Perkin-Elmer 1600 series
FTIR. Microanalyses were performed at the Purdue Mi-
croanalysis Laboratory, and all values were within (0.4% of
the calculated compositions. Silica gel used for column chro-
matography was 230-400 mesh.
3′,3′′-Dib r om o-4′,4′′-d im et h oxy-5′,5′′-b is(m et h oxyca r -
bon yl)-1-m eth oxy-2,2-d ip h en yleth en e (5). Methoxymeth-
yl(triphenyl)phosphonium bromide (257 mg, 0.75 mmol) was
suspended in anhydrous THF (4 mL), the mixture was stirred
3′,3′′-Dibr om o-4′,4′′-d im eth oxy-5′,5′′-bis(m eth oxyca r bo-
n yl)-1,1-d ip h en yleth en e (3). Methyl(triphenyl)phosphoni-

New Alkenyldiarylmethanes as Anti-HIV Agents
J ournal of Medicinal Chemistry, 1998, Vol. 41, No. 12 2083
under Ar in an ice bath, and sodium bis(trimethylsilyl)amide
(1.0 M in THF, 0.75 mL, 0.75 mmol) was added by syringe.
The mixture was stirred for 20 min, and a solution of 10 (258
mg, 0.5 mmol) in anhydrous THF (4 mL) was slowly injected.
The ice bath was removed, and the reaction mixture was
stirred for 24 h at ambient temperature, 3 h at 60 °C, and
overnight at ambient temperature. The reaction was quenched
with saturated ammonium chloride solution (5 mL). The
yellow organic layer was separated, and the aqueous layer was
extracted with benzene (2 × 10 mL). The combined organic
extracts were washed with brine (4 mL) and dried (Na2SO4).
The solvent was evaporated and the residue purified by flash
chromatography on silica gel (15 g), eluting with hexanes-
ethyl acetate (6:1), to give compound 5 as a colorless oil (76
mg, 28%) having an Rf of 0.15 on silica gel when hexanes-
ethyl acetate (6:1) was used as the solvent system: 1H NMR
(CDCl3, 300 MHz) δ 7.78 (d, J ) 2.1 Hz, 1 H), 7.74 (d, J ) 2.1
Hz, 1 H), 7.61 (d, J ) 2.2 Hz, 1 H), 7.58 (d, J ) 2.2 Hz, 1 H),
6.51 (s, 1 H), 4.01 (s, 6 H), 3.99 (s, 3 H), 3.97 (s, 3 H), 3.89 (s,
3 H); IR (neat) 2949, 1733, 1636, 1475, 1436, 1289, 1255, 1208,
1124, 1081, 1049, 998 cm-1; HRFABMS calcd for C21H21Br2O7
m/z 542.9654, found m/z 542.9661.
evaporated and the residue purified on silica gel (16 g), eluting
with hexanes-ethyl acetate (3:1), to afford the mesylate 8 (270
mg, 77%) as a colorless oil: 1H NMR (CDCl3, 300 MHz) δ 7.55
(m, 2 H), 7.51 (m, 2 H), 6.14 (t, J ) 7.4 Hz, 1 H), 4.30 (t, J )
6.2 Hz, 2 H), 3.99 (s, 3 H), 3.93 (s, 3 H), 3.93 (s, 3 H), 3.92 (s,
3 H), 3.04 (s, 3 H), 2.56 (q, J ) 7.0 Hz, 2 H); IR (neat) 2952,
1732, 1474, 1358, 1265, 1175, 1089, 995 cm-1. Anal. (C23H24
Br2SO9) C, H.
-
4-Azido-3′,3′′-dibr om o-4′,4′′-dim eth oxy-5′,5′′-bis(m eth ox-
yca r bon yl)-1,1-d ip h en yl-1-bu ten e (9). Compound 8 (231
mg, 0.363 mmol) was dissolved in dry N,N-dimethylformamide
(5 mL). Sodium azide (120 mg, 1.82 mmol) was added, and
the mixture was stirred at 35-50 °C for 3 h. The reaction
mixture was allowed to reach ambient temperature, and then
it was diluted with ethyl ether (42 mL). The ethereal solution
was washed with water (2 × 35 mL) and brine (1 × 35 mL)
and dried (MgSO4). The solvent was evaporated, and the
residue was purified on silica gel (16 g), eluting with hexanes-
ethyl acetate (3:1), to give 9 (132 mg, 62%) as a colorless
1
solid: mp 69-70 °C; H NMR (CDCl3, 300 MHz) δ 7.56 (m, 3
H), 7.50 (m, 1 H), 6.05 (m, 1 H), 3.99 (m, 1 H), 3.93 (m, 3 H),
3.40 (m, 2 H), 2.41 (m, 2 H); IR (KBr) 2944, 2105, 1731, 1473,
1436, 1246, 1207, 1085, 999, 959, 806, 726 cm-1
(C22H21Br2N3O6) C, H.
. Anal.
3′,3′′-Dib r om o-4′,4′′-d im et h oxy-5′,5′′-b is(m et h oxyca r -
b on yl)-1,1-d ip h en yl-4-[(ter t-b u t yld ip h en ylsilyl)oxy]-1-
bu ten e (6). [3-(tert-Butyldiphenylsilyloxy)propyl]triphenyl-
phosphonium bromide (595 mg, 0.93 mmol) was suspended in
anhydrous THF (6 mL) and the mixture stirred under Ar on
an ice bath. Sodium bis(trimethylsilyl)amide (1.0 M in THF,
1 mL) was added by syringe. The reaction mixture turned into
a bright orange solution and was stirred in an ice bath for 30
min. A solution of the ketone 10 (320 mg, 0.62 mmol) dissolved
in anhydrous THF (5 mL) was added, and the reaction mixture
was stirred at ambient temperature for 24 h. The mixture
was quenched with saturated ammonium chloride solution (10
mL), followed by ethyl acetate (10 mL). The organic layer was
separated, and the aqueous layer was extracted with ethyl
acetate (3 × 20 mL). The combined organic extracts were
washed with brine (15 mL) and dried (Na2SO4). The solvent
was evaporated and the yellow oily residue purified by flash
chromatography on silica gel (20 g), eluting with hexanes-
ethyl acetate (3:1), to give 6 (284 mg, 58%) as a yellow oil: 1H
NMR (CDCl3, 300 MHz) δ 7.67 (d, J ) 7.7 Hz, 4 H), 7.58 (m,
3 H), 7.51 (d, J ) 2.1 Hz, 1 H), 7.40 (m, 6 H), 6.10 (t, J ) 7.4
Hz, 1 H), 4.03 (s, 3 H), 3.98 (s, 3 H), 3.95 (s, 3 H), 3.93 (s, 3 H)
3.79 (t, J ) 6.1 Hz, 2 H), 2.39 (m, 2 H), 1.09 (s, 9 H); IR (neat)
3′,3′′-Dib r om o-4′,4′′-d im et h oxy-5′,5′′-b is(m et h oxyca r -
bon yl)-1,1-d ip h en yl-1-h ep ten e Ep oxid e (12). Compound
114 (67 mg, 0.116 mmol) was dissolved in dry methylene
chloride (1 mL) and the solution cooled in a freezer for 5 min.
3-Chloroperoxybenzoic acid [minimum 57% (70 mg)] was
dissolved in CH2Cl2 (0.5 mL) and injected into the solution.
The mixture was allowed to reach ambient temperature and
was stirred for 21 h. Solvent was evaporated, and the residue
was purified by flash column chromatography on silica gel (7.5
g), eluting with hexanes-ethyl acetate (20:1 followed by 10:
1), to give the epoxide 12 (43 mg, 62%) as an oil: 1H NMR
(CDCl3, 300 MHz) δ 7.74 (m, 2 H), 7.67 (m, 1 H), 7.65 (m, 1
H), 3.97 (s, 3 H), 3.94 (s, 3 H), 3.93 (s, 3 H), 3.92 (s, 3 H), 3.35
(m, 1 H), 1.45 (m, 4 H) 1.27 (m, 5 H), 0.88 (m, 3 H); IR (neat)
2953, 1732, 1472, 1435, 1260, 1207, 1087, 999, 720 cm -1. Anal.
(C25H28Br2O7) C, H.
2-(Tr im eth ylsilyl)eth yl 3′,3′′-Dich lor o-4′,4′′-d im eth oxy-
5,5′′-bis(m eth oxyca r bon yl)-3,3-d ip h en ylp r op en oa te (13).
A suspension of sodium hydride (0.018 g, 0.750 mmol) in dry
THF (5 mL) was stirred in an ice bath under an argon
atmosphere. Phosphonoacetate 28 (0.21 mL, 0.70 mmol) was
added, and the mixture was stirred at 0 °C for 1 h. The initial
2951, 2860, 1734, 1473, 1265, 1205, 998, 704 cm-1
(C38H40Br2O7Si) C, H.
. Anal.
suspension turned into a clear solution within minutes.
A
3′,3′′-Dib r om o-4-h yd r oxy-4′,4′′-d im e t h oxy-5′,5′′-b is-
(m eth oxyca r bon yl)-1,1-d ip h en yl-1-bu ten e (7). Compound
6 (266 mg, 0.33 mmol) was dissolved in dry THF (7 mL) and
the solution stirred at 0 °C under Ar. A 1.0 M solution of tetra-
n-butylammonium fluoride in THF (0.7 mL, 0.7 mmol) was
added. The solution turned yellow and was stirred at 0 °C
for 5.5 h. Brine (10 mL) was added, and the phases were
separated. The aqueous phase was extracted with ethyl
acetate (3 × 20 mL). The extract was dried (MgSO4), and the
solvent was evaporated. The residue was purified by flash
column chromatography on silica gel, eluting with hexanes-
ethyl acetate (3:1 to 1:1) to give 7 (129 mg, 70%) as a yellowish
oil: 1H NMR (CDCl3, 300 MHz) δ 7.58 (m, 3 H), 7.52 (m, 1 H),
6.14 (t, J ) 7.1 Hz, 1 H), 4.00 (s, 3 H), 3.96 (s, 3 H), 3.94 (s, 3
H), 3.93 (s, 3 H), 3.77 (t, J ) 6.1 Hz, 2 H), 2.41 (q, J ) 6.3 Hz,
2 H), 1.59 (brs, 1 H); IR (neat) 3430 (broad band), 2951, 1732,
1474, 1265, 1208, 998 cm-1. Anal. (C22H22Br2O7) C, H.
3′,3′′-Dibr om o-4-m eth a n esu lfon yloxy-4′,4′′-d im eth oxy-
5′,5′′-bis(m eth oxycar bon yl)-1,1-diph en yl-1-bu ten e (8). Com-
pound 7 (310 mg, 0.55 mmol) and anhydrous triethylamine
(0.23 mL, 1.7 mmol) were dissolved in dry dichloromethane
(7 mL), and the mixture was stirred under Ar at 0 °C. Mesyl
chloride (0.2 mL, 2.56 mmol) was added, and the mixture was
stirred at 0 °C for 3 h. The reaction mixture was diluted with
dichloromethane (10 mL) and washed with 0.5 N HCl (2 × 20
mL), followed by saturated NaHCO3 (20 mL) and brine (20
mL). The organic extract was dried (MgSO4). The solvent was
solution of ketone 11 (0.200 g, 0.469 mmol) in dry THF (4 mL)
was then added dropwise. The ice bath was removed, and the
reaction mixture was stirred at room temperature for 30 h.
The solvent was removed, and the residue was taken up in
cold water (30 mL) and ethyl ether (30 mL). The layers were
separated, and the aqueous one was extracted with ethyl ether
(2 × 30 mL). The combined organic fractions were washed
with brine (30 mL), dried over magnesium sulfate, and filtered.
The solvent was removed in vacuo to give a residue. After
flash chromatography on silica gel (35 g), eluting with hex-
anes-ethyl acetate (5:1), compound 13 (0.216 g, 81.2%) was
obtained as a thick oil: 1H NMR (300 MHz, CDCl3) δ 7.60 (d,
J ) 2.4 Hz, 1 H), 7.53 (d, J ) 2.2 Hz, 1 H), 7.39 (d, J ) 3.1 Hz,
1 H), 7.38 (d, J ) 2.5 Hz, 1 H), 6.31 (s, 1 H), 4.11 (m, J ) 8.7
Hz, 2 H), 3.99 (s, 3 H), 3.95 (s, 3 H), 3.91 (s, 3 H), 3.90 (s, 3 H),
0.89 (m, J ) 8.7 Hz, 2 H), 0.01 (s, 9 H); IR (film) 2952, 1737,
1477, 1251, 1161, 997, 859, 744 cm-1; FABMS m/z 568.8
(MH+). Anal. (C26H30Cl2O8Si) C, H.
3′,3′′-Dich lor o-4′,4′′-d im et h oxy-5′,5′′-b is(m et h oxyca r -
bon yl)-3,3-d ip h en ylp r op en oic Acid (14). A solution of
ester 13 (0.198 g, 0.348 mmol) in dry THF (10 mL) was stirred
under argon in an ice bath. A 1.0 M solution of tetra-n-
butylammonium fluoride (0.7 mL, 0.697 mmol) was added
dropwise and the reaction mixture stirred at 0 °C for 1.5 h.
The mixture turned into a light yellowish solution. Brine (30
mL) was added and the mixture stirred for 10 min. A 1.0 N
solution of HCl (10 mL) was then added, and the product was

2084 J ournal of Medicinal Chemistry, 1998, Vol. 41, No. 12
Cushman et al.
extracted with ethyl ether (3 × 30 mL). The combined organic
extracts were washed with brine (40 mL), dried over magne-
sium sulfate, and filtered, and the solvent was removed. Pure
14 (0.135 g, 83%) was obtained as a colorless crystalline solid
after flash chromatography on silica gel (20 g), using chloro-
form-methanol-formic acid (200:10:0.1 mL) as eluant: mp
60-62 °C; 1H NMR (300 MHz, CDCl3) δ 7.59 (d, J ) 2.4 Hz, 1
H), 7.50 (d, J ) 2.2 Hz, 1 H), 7.37 (d, J ) 2.2 Hz, 1 H), 7.35 (d,
J ) 2.4 Hz, 1 H), 6.29 (s, 1 H), 3.97 (s, 3 H), 3.93 (s, 3 H), 3.89
(s, 3 H), 3.88 (s, 3 H); IR (film) 3400-2900, 2955, 1731, 1477,
1262, 1210, 1164, 994, 743 cm-1; CIMS m/z (relative intensity)
469 (MH+, 25), 451 (MH+ - 18, 100), 437 (MH+ - 32, 23). Anal.
(C21H18Cl2O8‚0.4H2O) C, H.
Meth yl 3′,3′′-Dich lor o-4′,4′′-dim eth oxy-5′,5′′-bis(m eth ox-
yca r bon yl)-3,3-d ip h en ylp r op en oa te (15). A suspension of
sodium hydride (0.012 g, 0.493 mmol) in dry THF (5 mL) was
stirred in an ice bath under an argon atmosphere. Methyl
diethylphosphonoacetate (31) (0.09 mL, 0.469 mmol) was
added, and the mixture was stirred at 0 °C for 1 h. The initial
acetate (10 mL). The phases were separated, and the aqueous
one was extracted with ethyl acetate (3 × 20 mL). The
combined organic extracts were washed with brine (40 mL),
dried over magnesium sulfate, and filtered, and the solvent
was evaporated to give a dark brown oil. Purification by flash
chromatography (silica gel, 30 g, 3 × 14 cm column), eluting
with hexanes-ethyl acetate (3:1), provided 17 (0.26 g, 76%)
as a yellowish oil: 1H NMR (300 MHz, CDCl3) δ 7.63 (dd, J )
1.4 Hz, 4 H), 7.49 (d, J ) 2.3 Hz, 1 H), 7.46 (d, J ) 2.1 Hz, 1
H), 7.31 (d, J ) 2.0 Hz, 1 H), 7.28 (d, J ) 2.3 Hz, 1 H), 7.34
(m, 6 H), 6.10 (t, J ) 7.4 Hz, 1 H), 3.99 (s, 3 H), 3.94 (s, 3 H),
3.90 (s, 3 H), 3.88 (s, 3 H), 3.75 (t, J ) 6.1 Hz, 2 H), 2.36 (t, J
) 6.3 Hz, 1 H), 2.34 (t, J ) 6.4 Hz, 1 H), 1.05 (s, 9 H); IR
(film) 3050, 2951, 1737, 1475, 1428, 1270, 1202, 1093, 999, 910,
702 cm-1. Anal. (C38H40Cl2O7Si) C, H.
3′,3′′-Dich lor o-4-h yd r oxy-4′,4′′-d im e t h oxy-5′,5′′-b is-
(m eth oxycar bon yl)- 1,1-diph en yl-1-bu ten e (18). Silyl ether
17 (0.2 g, 0.282 mmol) was dissolved in dry THF (6 mL) and
stirred at 0 °C under argon. A 1.0 M solution of tetra-n-
butylammonium fluoride in THF (0.6 mL, 0.6 mmol) was
added, and the initially yellow solution turned into an orange
solution which was stirred at 0 °C for 5.5 h. Brine (10 mL)
was added, and the phases were separated. The aqueous one
was extracted with ethyl acetate (3 × 20 mL). The combined
organic extracts were washed with brine (40 mL), dried over
magnesium sulfate and filtered, and the solvent was evapo-
rated to give an orange oil. Purification by flash chromatog-
raphy (silica gel, 20 g, 2 × 14 cm column) using hexanes-
ethyl acetate (1:1) as the eluant afforded 1814 (94.5 mg, 71.4%)
as a colorless oil: 1H NMR (300 MHz, CDCl3) δ 7.52 (d, J )
2.4 Hz, 1 H), 7.50 (d, J ) 2.1 Hz, 1 H), 7.37 (d, J ) 2.1 Hz, 1
H), 7.31 (d, J ) 1.8 Hz, 1 H), 6.13 (t, J ) 7.4 Hz, 1 H), 3.99 (s,
3 H), 3.93 (s, 3 H), 3.92 (s, 3 H), 3.91 (s, 3 H), 3.75 (t, J ) 6.3
Hz, 2 H), 2.38 (q, J ) 13.4 and J ) 6.7 Hz, 1 H), 1.66 (bs, 1 H);
IR (film) 3542, 2951, 2874, 1732, 1477, 1428, 1268, 1210, 1093,
suspension turned into a clear solution within minutes.
A
solution of ketone 11 (0.100 g, 0.235 mmol) in dry THF (5 mL)
was added dropwise. The ice bath was removed, and the
reaction mixture was stirred at room temperature for 30 h.
Cold water (15 mL) was added, and the mixture was stirred
for 10 min. The product was extracted with ethyl ether (3 ×
25 mL). The combined organic fractions were washed with
brine (30 mL), dried over magnesium sulfate, and filtered. The
solvent was removed in vacuo to give a residue. After
purification by flash chromatography on silica gel (35 g),
eluting with hexanes-ethyl acetate (2:1), compound 15 (0.0948
g, 83.8%) was obtained as a thick colorless oil: 1H NMR (300
MHz, CDCl3) δ 7.59 (d, J ) 2.4 Hz, 1 H), 7.53 (d, J ) 2.2 Hz,
1 H), 7.37 (d, J ) 2.2 Hz, 1 H), 7.36 (d, J ) 2.4 Hz, 1 H), 6.32
(s, 1 H), 3.99 (s, 3 H), 3.94 (s, 3 H), 3.89 (s, 3 H), 3.88 (s, 3 H),
3.63 (s, 3 H); IR (film) 2951, 1731, 1477, 1435, 1264, 1164,
996 cm-1; CIMS m/z (relative intensity) 483 (MH+, 30) and
451 (MH+ - CH3OH, 100). Anal. (C22H20Cl2O8) C, H.
998, 866, 743 cm-1
.
3′,3′′-Dich lor o-4-m eth a n esu lfon yloxy-4′,4′′-d im eth oxy-
5′,5′′-bis(m eth oxyca r bon yl)-1,1-d ip h en yl-1-bu ten e (19). A
solution of alcohol 18 (0.700 g, 1.491 mmol) and triethylamine
(0.62 mL, 4.473 mmol) in dry dichloromethane (20 mL) was
stirred under argon at 0 °C. Mesyl chloride (0.35 mL, 4.473
mmol) was added, and the mixture was stirred at 0 °C for 3 h.
The reaction mixture was then diluted with dichloromethane
(30 mL) and washed with 0.5 N HCl (2 × 40 mL), followed by
saturated NaHCO3 (40 mL) and brine (40 mL). The organic
extract was dried over magnesium sulfate and filtered, and
the solvent was removed in vacuo to produce a thick yellow
oil (0.77 g). Purification of a fraction of this oil (0.557 g) by
flash chromatography on silica gel (25 g) afforded pure 19
(0.521 g, 88.5%) as a thick oil, which slowly crystallized. The
analytical sample was obtained by recrystallization from
chloroform-methanol: mp 83-85 °C; 1H NMR (300 MHz,
CDCl3) δ 7.49 (d, J ) 2.4 Hz, 1 H), 7.47 (d, J ) 2.2 Hz, 1 H),
7.31 (d, J ) 2.1 Hz, 1 H), 7.29 (d, J ) 2.3 Hz, 1 H), 6.04 (t, J
) 7.4 Hz, 1 H), 4.27 (t, J ) 6.3 Hz, 2 H), 3.97 (s, 3 H), 3.91 (s,
3 H), 3.89 (s, 3 H), 3.88 (s, 3 H), 3.00 (s, 3 H), 2.53 (q, J ) 6.4
Hz and J ) 7.2 Hz, 2 H); IR (film) 2952, 1731, 1479, 1359,
1269, 1174, 995 cm-1; CIMS m/z (relative intensity) 547 (MH+,
46), 515 (100). Anal. (C23H24Cl2O9S) C, H.
4-Azido-3′,3′′-dich lor o-4′,4′′-dim eth oxy-5′,5′′-bis(m eth ox-
yca r bon yl)-1,1-d ip h en yl-1-bu ten e (20). Mesylate 19 (0.215
g, 0.393 mmol) was dissolved in dry DMF (5 mL). Sodium
azide (0.13 g, 1.965 mmol) was added, and the mixture was
stirred at 35-50 °C for 3 h. The mixture was allowed to cool
at room temperature, and then it was diluted with ether (45
mL). The ethereal solution was washed with water (2 × 40
mL) and brine (40 mL) and dried over magnesium sulfate.
After filtration and evaporation of the solvent in vacuo, a
yellowish oil was obtained. Purification by flash chromatog-
raphy on silica gel (16 g), eluting with hexanes-ethyl acetate
(3:1), afforded pure 20 (0.148 g, 76.1%) as an oil which slowly
crystallized. The analytical sample was obtained by recrys-
tallization from chloroform-pentane: mp 70-72 °C; 1H NMR
(300 MHz, CDCl3) δ 7.50 (t, J ) 2.1 Hz, 2 H), 7.34 (d, J ) 2.2
ter t-Bu t yl 3′,3′′-Dich lor o-4′,4′′-d im et h oxy-5′,5′′-b is-
(m eth oxyca r bon yl)-3,3-d ip h en ylp r op en oa te (16). tert-
Butyl diethylphosphonoacetate (32) (0.44 mL, 1.872 mmol) was
dissolved in dry THF (15 mL), and the mixture was stirred
under argon in an ice bath. A 1.0 M solution of sodium bis-
(trimethylsilyl)amide (2.0 mL, 2.01 mmol) was added, and the
solution was stirred at 0 °C for 1 h. At this time, a solution of
the ketone 1141 (0.400 g, 0.936 mmol) in dry THF (12 mL) was
added dropwise, and the resulting mixture was stirred at room
temperature for 24 h. The solvent was evaporated and the
residue partitioned between ethyl ether (40 mL) and water
(60 mL). The layers were separated, and the aqueous one was
extracted with ethyl ether (2 × 40 mL). The combined organic
extracts were dried over magnesium sulfate and filtered, and
the solvent was removed in vacuo to give a yellowish oil.
Purification by flash chromatography (silica gel, 30 g), eluting
with hexanes-ethyl acetate (3:1), afforded pure 16 (0.229 g,
46.6%) as a white solid: mp 114-115.5 °C; 1H NMR (300 MHz,
CDCl3) δ 7.57 (d, J ) 2.4 Hz, 1 H), 7.51 (d, J ) 2.3 Hz, 1 H),
7.37 (d, J ) 2.2 Hz, 1 H), 7.35 (d, J ) 2.4 Hz, 1 H), 6.22 (s, 3
H), 3.98 (s, 3 H), 3.94 (s, 3 H), 3.90 (s, 3 H), 3.88 (s, 3 H), 1.29
(s, 3 H); IR (film) 2952, 1731, 1479, 1368, 1258, 1095, 998,
848, 744 cm-1; CIMS m/z (relative intensity) 451 (MH+ - C4H8,
100), 469 (MH+ - C4H9OH, 92), 470 (MH+ - C4H9O, 64). Anal.
(C25H26Cl2O8) C, H.
3′,3′′-Dich lor o-4′,4′′-d im et h oxy-5′,5′′-b is(m et h oxyca r -
b on yl)-1,1-d ip h en yl-4-[(ter t-b u t yld ip h en ylsilyl)oxy]-1-
bu ten e (17). [3-(tert-Butyldiphenylsilyloxy)propyl]triphenyl-
phosphonium bromide (0.45 g, 0.702 mmol) was suspended in
dry THF (5 mL) and stirred under argon. The suspension was
cooled in an ice bath. A 1.0 M solution of NaHMDS (0.75 mL,
0.75 mmol) in THF was added dropwise. The reaction mixture
turned into a bright orange solution and was stirred in the
ice bath for 30 min. A solution of the ketone 11 (0.200 g, 0.468
mmol) in dry THF (2 mL) was added. The solution was stirred
at room temperature for 24 h. A saturated solution of
ammonium chloride (10 mL) was then added, followed by ethyl

New Alkenyldiarylmethanes as Anti-HIV Agents
J ournal of Medicinal Chemistry, 1998, Vol. 41, No. 12 2085
Hz, 1 H), 7.30 (d, J ) 2.4 Hz, 1 H), 6.05 (t, J ) 7.4 Hz, 1 H),
3.99 (s, 3 H), 3.92 (s, 3 H), 3.91 (s, 3 H), 3.90 (s, 3 H), 3.39 (t,
J ) 6.6 Hz, 2 H), 2.39 (q, J ) 6.7 Hz and J ) 7.2 Hz, 2 H); IR
(film) 2952, 2098, 1734, 1477, 1267, 997, 742 cm-1; CIMS m/z
1H NMR (300 MHz, CDCl3) δ 7.64-7.60 (m, 4 H), 7.46 (d, J )
2.4 Hz, 1 H), 7.43 (d, J ) 2.2 Hz, 1 H), 7.39-7.31 (m, 6 H),
7.27 (dd, J ) 2.4 Hz, 2 H), 6.01 (t, J ) 7.5 Hz, 1 H), 3.96 (s, 3
H), 3.91 (s, 3 H), 3.88 (s, 3 H), 3.87 (s, 3 H), 3.61 (t, J ) 5.7
Hz, 1 H), 2.02 (q, J ) 7.1 Hz, 2 H), 1.51 (m, 4 H), 1.01 (s, 9 H):
(relative intensity) 494 (MH+, 100), 496 (70). Anal. (C22H21
-
IR (film): 2934, 1736, 1477, 1260, 1093, 998, 702 cm-1
.
Cl2N3O6‚0.5H2O) C, H.
FABMS m/z (relative intensity) 703 (MH+ - CH3OH, 7) and
4-Am in o-3′,3′′-dich lor o-4′,4′′-dim eth oxy-5′,5′′-bis(m eth ox-
yca r bon yl)-1,1-d ip h en yl-1-bu ten e (21). A solution of azide
20 (0.228 g, 0.462 mmol) and P(OEt)3 (0.24 mL, 1.387 mmol)
in benzene (6 mL) was stirred under argon at room temper-
ature for 24 h. The reaction mixture was then saturated with
dry HCl for 10 min and stirred for 48 h at room temperature.
The solvent was removed, and dry ethyl ether (15 mL) was
added. The solution was placed in the freezer for 48 h. The
precipitated amine hydrochloride was separated by filtration,
washed with cold ethyl ether, and dried under high vacuum
overnight to provide 21 (0.200 g, 86%) as a white solid. The
analytical sample was recrystallized from ethanol-ethyl
ether-pentane: mp 156-158 °C; 1H NMR (300 MHz, CDCl3)
δ 7.49 (t, J ) 2.3 Hz, 2 H), 7.47 (d, J ) 2.2 Hz, 1 H), 7.32 (d,
J ) 2.2 Hz, 1 H), 7.29 (d, J ) 2.4 Hz, 1 H), 6.06 (t, J ) 7.4 Hz,
1 H), 3.96 (s, 3 H), 3.90 (s, 3 H), 3.89 (s, 3 H), 3.88 (s, 3 H),
2.81 (t, J ) 6.6 Hz, 2 H), 2.25 (q, J ) 7.1 Hz, 2 H), 1.90 (bs, 2
H, exchangeable with D2O); IR (film) 2951, 1731, 1476, 1435,
1261, 1208, 997, 742 cm-1; CIMS m/z (relative intensity) 467
(M+, 90), 466 (M+ - 1, 100). Anal. (C22H23Cl2NO6‚HCl) C, H,
N.
677 (M+ - C4H9, 35). Anal. (C40H44Cl2O7Si) C, H.
3′,3′′-Dich lor o-4′,4′′-d im et h oxy-5′,5′′-b is(m et h oxyca r -
bon yl)-1,1-d ip h en yl-1-h exen -6-ol (24). Silyl ether 23 (3.905
g, 5.318 mmol) was dissolved in dry THF (50 mL) and stirred
at 0 °C under an argon atmosphere. A 1.0 M solution of TBAF
in THF (10.6 mL, 10.63 mmol) was added. The reaction
mixture was stirred at 0 °C for 2 h. The ice bath was then
removed, and the mixture was stirred at 25 °C for 2 h. Brine
(60 mL) was added to quench the reaction. The phases were
separated, and the aqueous one was extracted with Et2O (3 ×
50 mL). The organic extracts were combined and washed with
brine (1 × 70 mL), dried over MgSO4, and filtered. Purification
by flash chromatography on silica gel (150 g, column: 5 cm ×
17.5 in.), eluting with hexanes-ethyl acetate (1:1), followed
by ethyl acetate-hexanes (2:1), afforded compound 24 as a
1
white solid in good yield (75%): mp 94-96 °C; H NMR (300
MHz, CDCl3) δ 7.48 (d, J ) 2.3 Hz, 1 H), 7.46 (d, J ) 2.1 Hz,
1 H), 7.30 (d, J ) 2.2 Hz, 1 H), 7.28 (d, J ) 2.2 Hz, 1 H), 6.05
(t, J ) 7.5 Hz, 1 H), 3.98 (s, 3 H), 3.91 (s, 6 H), 3.89 (s, 3 H),
3.60 (t, J ) 5.7 Hz, 1 H), 2.11 (q, J ) 7.0 Hz, 2 H), 1.61-1.50
(m, 4 H); IR (film) 3500-3200, 2936, 1735, 1477, 1258, 998,
743 cm-1. Anal. (C24H26Cl2O7) C, H.
Meth yl 3′,3′′-Dich lor o-4′,4′′-dim eth oxy-5′,5′′-bis(m eth ox-
yca r bon yl)-6,6-d ip h en ylh exen oa te (22). (4-Methoxycar-
bonylbutyl)triphenylphosphonium bromide (33)42 (0.321 g,
0.704 mmol) was stirred in dry THF (15 mL) under argon at
-78 °C. A 1.0 M solution of NaN(SiMe3)2 in THF (0.78 mL,
0.78 mmol) was then added, and the yellow solution was
stirred in a dry ice-acetone bath for 1 h. A -78 °C solution
of ketone 11 (0.200 g, 0.469 mmol) in dry THF (5 mL) was
added, and the reaction mixture was stirred at -78 °C for 12
h and then at room temperature for 12 h. Saturated NH4Cl
(25 mL) was added and the mixture stirred for 15 min. The
layers were separated, and the aqueous phase was extracted
with ethyl acetate (3 × 30 mL). The combined organic extracts
were washed with brine (40 mL), dried over magnesium sulfate
and filtered, and the solvent was removed in vacuo to give a
thick orange residue. Purification was achieved by flash
chromatography (silica gel, 23 g, 2 × 20.1 cm column), eluting
with hexane-ethyl acetate (3:1), to provide 22 (0.110 g, 44.6%)
as a pale yellow oil: 1H NMR (300 MHz, CDCl3) δ 7.51 (d, J )
2.3 Hz, 1 H), 7.48 (d, J ) 2.2 Hz, 1 H), 7.33 (d, J ) 2.2 Hz, 1
H), 7.30 (d, J ) 2.3 Hz, 1 H), 6.05 (t, J ) 7.5 Hz, 1 H), 4.01 (s,
3 H), 3.95 (s, 3 H), 3.94 (s, 3 H), 3.93 (s, 3 H), 3.65 (s, 3 H),
2.32 (t, J ) 7.4 Hz, 2 H), 2.15 (q, J ) 7.4 Hz, 2 H), 1.80 (m, J
) 7.3 Hz, 2 H); IR (film) 2951, 1736, 1477, 1261, 1208, 1093,
999, 743 cm-1; FABMS m/z (relative intensity) 525 (MH+, 30),
3′,3′′-Dich lor o-4′,4′′-d im et h oxy-5′,5′′-b is(m et h oxyca r -
bon yl)-6,6-d ip h en yl-5-h exen oic Acid (25). A solution of
chromium trioxide (0.101 g, 1.01 mmol) and 0.75 N sulfuric
acid (1.6 mL, 2.323 mmol) was stirred in an ice bath.
A
solution of alcohol 24 (0.100 g, 0.202 mmol) in acetone (10 mL)
was added over 6 h, while the temperature was maintained
below 5 °C. After the addition was finished, the reaction
mixture was stirred at 25 °C for 2 h. It was left overnight
without stirring. The solvent was removed, and the residue
was diluted with water (5 mL). The mixture was extracted
with ethyl acetate (3 × 15 mL). The combined organic extracts
were washed with water (1 × 25 mL) and brine (1 × 25 mL),
dried over magnesium sulfate, and filtered. The solvents were
removed, and the residue was purified by flash chromatogra-
phy on silica gel (30 g, column: 2 cm × 21 cm), eluting with
hexanes-ethyl acetate (1:1). Compound 24 was obtained as
a colorless oil in moderate yield (44 mg, 42.8%): 1H NMR (300
MHz, CDCl3) δ 7.47 (d, J ) 2.3 Hz, 1 H), 7.44 (d, J ) 2.2 Hz,
1 H), 7.29 (d, J ) 2.2 Hz, 1 H), 7.26 (d, J ) 2.3 Hz, 1 H), 6.02
(t, J ) 7.5 Hz, 1 H), 3.96 (s, 3 H), 3.90 (s, 3 H), 3.89 (s, 3 H),
3.88 (s, 3 H), 2.32 (t, J ) 7.3 Hz, 2 H), 2.14 (q, J ) 7.5 Hz, 2
H), 1.76 (qn, J ) 7.4 Hz, 2 H); IR (film) 3400-2500, 2951, 1732,
1477, 1263, 1209, 998. 742 cm-1; FABMS m/z (relative
intensity): 511 (MH+, 20) and 479 (MH+ - CH3OH, 50). Anal.
(C24H24Cl2O8) C, H.
509 (M+ - CH3, 28), 493 (M+ - OCH3, 100). Anal. (C25H26
Cl2O8) C, H.
-
3′,3′′-Dich lor o-4′,4′′-d im et h oxy-5′,5′′-b is(ca r b oxy)-6,6-
d ip h en yl-5-h exen oic Acid (26). Compound 22 (0.403 g,
0.796 mmol) was dissolved in MeOH (6 mL), and 10% aqueous
KOH (10 mL) was added. The mixture was heated at 60 °C
for 24 h. The solvent was removed, and the aqueous residue
was diluted with water (10 mL) and washed with ethyl acetate
(15 mL). It was then acidified with concentrated HCl and
extracted with ethyl acetate (3 × 15 mL). The combined
organic extracts were washed with brine (1 × 20 mL), dried
over magnesium sulfate, and filtered. After evaporation of the
solvent, compound 26 was obtained as an off-white solid (0.34
g, 91.7%): mp 203-206 °C; 1H NMR (300 MHz, acetone-d6) δ
7.58 (dd, J ) 2.4 and J ) 2.1 Hz, 2 H), 7.52 (d, J ) 2.4 Hz, 1
H), 7.50 (d, J ) 2.3 Hz, 1 H), 6.28 (t, J ) 7.5 Hz, 1 H), 3.95 (s,
3 H), 3.89 (s, 3 H), 2.30 (t, J ) 7.2 Hz, 2 H), 2.20 (q, J ) 7.4
Hz, 2 H), 1.78 (qn, J ) 7.3 Hz, 2 H); IR (film) 3500-2500,
2930, 1708, 1477, 1256, 998 cm-1; FABMS m/z (relative
intensity) 483 (MH+, 10) and 465 (MH+ - H2O, 25). Anal.
(C22H20Cl2O8) C, H.
3′,3′′-Dich lor o-4′,4′′-d im et h oxy-5′,5′′-b is(m et h oxyca r -
b on yl)-1,1-d ip h en yl-6-[(ter t-b u t yld ip h en ylsilyl)oxy]-1-
h exen e (23). A suspension of [5-(tert-butyldiphenylsilanyl-
oxy)pentyl]triphenylphosphonium bromide29 (8.66 g, 13.00
mmol) in dry THF (150 mL) was stirred at -78 °C under an
argon atmosphere. A 1.0 M solution of NaN(TMS)2 in THF
(13.9 mL, 13.9 mmol) was added dropwise. The mixture
turned into a bright orange solution and was stirred at -78
°C for 45 min. A solution of benzophenone 11 (3.69 g, 8.66
mmol) in dry THF (50 mL) was then added dropwise. The
reaction mixture was stirred at 0 °C for 1.5 h. The reaction
mixture was then quenched with saturated NH4Cl solution (70
mL). The phases were separated, and the aqueous one was
extracted with Et2O (3 × 50 mL). The combined organic
extracts were washed with brine (1 × 70 mL), dried over
magnesium sulfate, and filtered. The solvent was removed,
and the residue was chromatographed on silica gel (200 g,
column: 5 cm × 10.5 in.), eluting with hexane-ethyl acetate
(6:1) to hexane-ethyl acetate (5:1). Compound 23 was ob-
tained in moderate yield (4.00 g, 63% yield) as a colorless oil.
3′,3′′-Dich lor o-4′,4′′-d im et h oxy-5′,5′′-b is(ca r b oxy)-4,4-

2086 J ournal of Medicinal Chemistry, 1998, Vol. 41, No. 12
Cushman et al.
d ip h en yl-3-bu ten oic Acid (27). Chromium trioxide (0.64 g,
6.39 mmol) was dissolved in 1.5 M sulfuric acid (9.3 mL, 13.9
mmol), and the solution was stirred in an ice bath. A solution
of alcohol 18 (0.50 g, 1.06 mmol) in acetone (15 mL) was then
added and the ice bath removed. The reaction mixture was
stirred at room temperature for 7 h. Ethyl ether (50 mL) was
added, and the phases were separated. The organic phase was
washed with water (3 × 40 mL) and then extracted with 3 M
sodium hydroxide (3 × 20 mL). The combined aqueous
extracts were acidified with concentrated hydrochloric acid,
and the cloudy solution was kept in the refrigerator overnight.
Separation of the precipitated solid by filtration, followed by
washing with water, afforded a yellowish solid (0.131 g), which
was purified by recrystallization from ethyl ether-dichlo-
romethane to yield 27 (63 mg, 12.2%) as a pale yellow solid:
n on e (39). A solution of intermediate 38 (0.5 g, 1.8 mmol) in
acetic anhydride (25 mL) was cooled to 0 °C in an ice bath
containing NaCl. Solid chromium(VI) oxide (3 g, 30 mmol) was
added slowly to the solution at 0 °C. After complete addition,
the mixture was stirred at 0 °C for 1 h and then room
temperature for 12 h. The resulting viscous paste was broken
up with ethyl acetate and partitioned between 1 N HCl (200
mL) and ethyl acetate (200 mL). The organic layer was
washed with 1 N HCl (100 mL) and brine (100 mL) and dried
over Na2SO4, and the solvent was removed under reduced
pressure. Trituration of the solid in 1 N HCl and filtering gave
the product 39 (0.12 g, 22%) as an off white solid: mp 142-
144 °C; 1H NMR (acetone-d6) δ 8.14 (d, J ) 2.2 Hz, 2 H), 7.96
(dd, J ) 2.2, 8.7 Hz, 1 H), 7.30 (d, J ) 8.7 Hz, 1 H), 3.99 (s, 3
H), 3.84 (s, 3 H); FTIR (KBr) 2953, 2849, 1735, 1710, 1650,
1
mp 206-207 °C; H NMR (300 MHz, acetone-d6) δ 7.65 (d, J
1603, 1502, 1438, 1406, 1274, 1152, 1081, 1010, 950 cm-1
Anal. (C19H18O7) C, H.
.
) 2.3 Hz, 1 H), 7.62 (d, J ) 2.1 Hz, 1 H), 7.57 (d, J ) 2.1 Hz,
1 H), 7.52 (d, J ) 2.3 Hz, 1 H), 6.42 (t, J ) 7.4 Hz, 1 H), 3.97
(s, 6 H), 3.91 (s, 6 H), 3.20 (d, J ) 7.4 Hz, 2 H); IR (film) 3400-
2800, 2938, 1702, 1478, 1259, 996, 708 cm-1; FABMS m/z
(relative intensity) 454 (M+, 45), 437 (M+ - 17, 100). Anal.
(C20H16Cl2O8‚0.4H2O) C, H.
4′,4′′-Dim e t h oxy-3′,3′′-b is(m e t h oxyca r b on yl)-1,1-d i-
p h en yl-1-h ep ten e (40). n-Hexyltriphenylphosphonium bro-
mide (0.427 g, 1 mmol) was dried by azeotropic distillation
from a benzene solution and then stirred in dry THF (10 mL)
under nitrogen atmosphere. Sodium bis(trimethylsilyl)amide
(1 M in THF, 1 mL, 1 mmol) was added, and the ylide produced
was stirred under nitrogen at 0 °C for 30 min. Intermediate
39 (0.276 g, 0.77 mmol) was added as a solution in THF (10
mL) under nitrogen. The mixture was stirred at room tem-
perature overnight and partitioned between 1 N HCl (100 mL)
and ethyl acetate (100 mL). The organic layer was dried over
sodium sulfate and evaporated to afford an oil which was
chromatographed on silica gel (50 g), eluting with hexanes-
ethyl acetate (4:1) to give the product 40 (0.15 g, 46%) as an
oil: 1H NMR (CDCl3, 300 MHz) δ 7.63 (d, J ) 2.3 Hz, 1 H),
7.56 (d, J ) 2.2 Hz, 1 H), 7.20 (dt, J ) 2.3 Hz, 1 H), 6.94 (d, J
) 8.6 Hz, 1 H), 6.82 (d, J ) 8.7 H, 1 H), 5.96 (t, J ) 7.5 Hz, 1
H), 3.90 (s, 3 H), 3.84 (s, 3 H), 3.83 (s, 6 H), 2.05 (q, J ) 7.3
Hz, 2 H), 1.39 (t, J ) 7.2 Hz, 2 H), 1.22 (m, J ) 1.9 Hz, 2 H),
0.83 (t, J ) 6.7 Hz, 3 H); IR (neat) 2927, 2853, 1732, 1606,
1500, 1435, 1263 cm-1. Anal. (C25H30O6) C, H.
4,4′-Dim et h oxy-3,3′-b is(m et h oxyca r b on yl)-5,5′-d in i-
tr oben zop h en on e (41). A solution of compound 39 (1.07 g,
3 mmol) in acetic anhydride (30 mL) was cooled to 0 °C. Nitric
acid (90%, 20 mL) was added dropwise, and the solution was
stirred overnight while warming to room temperature. The
orange solution was poured onto ice and water and extracted
with ethyl acetate (3 × 100 mL). The organic layer was
washed with 5% KOH solution (3 × 50 mL), dried over MgSO4,
and evaporated. The oil (1.1 g) was flash chromatographed
on silica gel (250 g), eluting with hexanes-ethyl acetate (10:
2), to afford 41 (0.41 g, 32%) as a solid: mp 96-98 °C; 1H NMR
(CDCl3, 300 MHz) δ 8.55 (s, 2 H), 8.41 (s, 2 H), 4.1 (s, 6 H),
3.99 (s, 6 H). Anal. (C19H16H2O11) C, H, N.
3,3′-Dia m in o-5,5′-bis(m eth oxyca r bon yl)-4,4′-d im eth ox-
yben zop h en on e (42). The dinitro compound 41 (0.33 g, 0.9
mmol) was hydrogenated at atmospheric pressure over plati-
num oxide (0.2 g, 0.08 mmol) in ethyl acetate (50 mL). After
TLC (silica gel, hexanes-acetone, 10:2) had shown that all the
starting material was consumed, the catalyst was removed by
filtration and the solvent was removed at reduced pressure to
give an oil. The oil was flash chromatographed on silica gel
(30 g) using ethyl acetate. Evaporation of the solvent gave
the product 42 (0.24 g, 80%) as a glassy solid: 1H NMR (CDCl3,
300 MHz) δ 7.55 (d, J ) 2.1 Hz, 2 H), 7.31 (d, J ) 2.1 Hz, 2
H), 3.91 (s, 6 H), 3.89 (s, 6 H); IR (KBr) 3369, 2945, 2837, 1717,
1616 cm-1. Anal. (C19H20H2O7) C, H, N.
3,3′-Diiod o-4,4′-d im eth oxy-5,5′-bis(m eth oxyca r bon yl)-
ben zop h en on e (43). A suspension of compound 42 (0.57 g,
1.4 mmol) in water (10 mL) was cooled to 0 °C. Concentrated
HCl (0.6 mL) was added dropwise to give a yellow solution.
After 10 min, sodium nitrite (0.22 g, 3.2 mmol) dissolved in
water (2 mL) was added and the solution was stirred for 30
min at 0 °C. The solution was then poured into a solution of
iodine (1 g, 3.9 mmol) and potassium iodide (1.0 g, 5.9 mmol)
in water (100 mL). The solution was stirred at room temper-
ature for 30 min. Extraction with ethyl acetate (200 mL),
(2-Tr im eth ylsilyl)eth yl Dieth ylph osph on oacetate (28).43
BOP-Cl (2.53 g, 9.95 mmol) was added to a solution of
diethylphosphonoacetic acid (29) (1.6 mL, 10 mmol), 2-(tri-
methylsilyl)ethanol (30) (1.57 mL, 10.9 mmol), and triethyl-
amine (2.77 mL, 19.9 mmol) in dry dichloromethane (25 mL).
The initial suspension turned into a clear solution within
minutes, which was stirred at room temperature under Ar for
1.2 h. A 5% aqueous solution of sodium carbonate (60 mL)
was added, and the phases were separated. The organic phase
was diluted with dichloromethane (2 × 30 mL) and washed
with water (50 mL) and brine (50 mL). The organic phase
was dried over magnesium sulfate and filtered and the solvent
evaporated to give a liquid residue (6.89 g). Purification by
flash chromatography (silica gel, 135 g, 5 × 20.3 cm column),
eluting with hexanes-ethyl acetate (2:1), afforded 28 as a
colorless liquid (2.47 g, 84%): bp 120-122 °C/0.05 mmHg (lit.43
bp 140-145 °C/0.1 mmHg); 1H NMR (300 MHz, CDCl3) δ 4.18
(m, J ) 8.6 Hz, 2 H), 4.14 (m, J ) 7.2 Hz, 4 H), 2.94 (s, 1 H),
2.87 (s, 1 H), 1.31 (t, J ) 7.1 Hz, 6 H), 0.98 (m, J ) 8.7 Hz, 2
H), 0.01 (s, 9 H); IR (film) 2981, 2954, 2904, 1737, 1268, 1027,
969, 838 cm-1. Anal. (C11H25O5PSi) C, H.
1-Br om o-4,4-bis[8′,8′′-d ich lor o-2′,2′,2′′,2′′-tetr a m eth yl-
4′,4′′-d ioxo-6′,6′′-(1,3-ben zod ioxyl)]-3-bu ten e (35). A solu-
tion of alcohol 3430 (0.106 g, 0.215 mmol) and carbon tetra-
bromide (0.09 g, 0.271 mmol) in dry acetonitrile (8.5 mL) was
stirred under argon. A solution of triphenylphosphine (0.08
g, 0.305 mmol) in dry acetonitrile (1.5 mL) was added drop-
wise. The reaction mixture was stirred at reflux for 20 h. The
solvent was removed in vacuo, and the resulting oil was
extracted with ethyl ether (5 × 5 mL). The solvent was
evaporated from the combined organic extracts to give a thick
solid. Purification by flash chromatography on silica gel (25
g), eluting with hexanes-ethyl acetate (5:1), afforded the
product 35 (66 mg, 56%) as a yellowish solid: mp 175-178
1
°C; H NMR (CDCl3, 300 MHz) δ 7.70 (d, J ) 2.0 Hz, 1 H),
7.69 (d, J ) 1.8 Hz, 1 H), 7.45 (d, J ) 2.2 Hz, 1 H), 7.44 (d, J
) 2.1 Hz, 1 H), 6.09 (t, J ) 7.2 Hz, 1 H), 3.45 (t, J ) 6.5 Hz,
2 H), 2.70 (q, J ) 6.7 Hz, 2 H), 1.84 (s, 6 H), 1.80 (s, 6 H); IR
(film) 2999, 1745, 1607, 1483, 1283, 1199, 1063, 874, 756 cm-1
;
CIMS m/z (relative intensity) 555 (MH+, 55), 557 (MH+ + 2,
100), 559 (MH+ + 4, 40). Anal. (C24H21BrCl2O6) C, H.
4,4′-Dim et h oxy-3,3′-b is(m et h oxyca r b on yl)d ip h en yl-
m eth a n e (38). A suspension of 3,3′-dicarboxy-4,4′-dihydroxy-
diphenylmethane (37)33 (0.576 g, 2 mmol), dimethyl sulfate
(2 mL, 12 mmol), and potassium carbonate (2.0 g) in acetone
(20 mL) was heated at reflux for 6 h. The solid mass was
separated by filtration and washed with acetone. Evaporation
of the acetone gave the product 38 (0.51 g, 80%) as a brown
oil: 1H NMR (CDCl3, 300 MHz) δ 7.61 (d, J ) 1.8 Hz, 2 H),
7.25 (dd, J ) 1.8, 8.6 Hz, 2 H), 6.90 (d, J ) 8.5 Hz, 2 H), 3.90
(s, 2 H), 3.87 (s, 6 H). Anal. (C19H20O6) C, H.
4,4′-Dim et h oxy-3,3′-b is(m et h oxyca r b on yl)b en zop h e-

New Alkenyldiarylmethanes as Anti-HIV Agents
J ournal of Medicinal Chemistry, 1998, Vol. 41, No. 12 2087
washing with 10% sodium hydrosulfate solution (100 mL),
drying over MgSO4, and evaporation of the solvent gave the
crude diiodide (0.6 g). Recrystallization from hexanes-meth-
ylene chloride gave the pure product 43 (0.54 g, 63%) as a
Ser-Gln-Asn-Tyr-Pro-Ile-Val-Gln-NH2, Multiple Peptide Sys-
tems, San Diego, CA) were utilized to determine the concen-
tration of test compound required to inhibit protease activity
by 50% (IC50). Briefly, HIV-1 protease (14.2 nM final) was
mixed with various concentrations of test compounds in 250
mM potassium phosphate buffer, pH 6.5, 2.5% (v/v) glycerol,
0.5 mM dithiothreitol, 0.5 mM EDTA, and 375 mM ammonium
sulfate, after which the substrate was added (30 nmol) and
the reaction incubated at 37 °C for 30 min. Reactions were
terminated by the addition of 20 µL of a mixture of 8 M
guanidine-HCl to 10% trifluoroacetic acid (8:1), and the
reaction products were separated by reverse-phase HPLC on
a Nova-Pak C-18 column. Absorbance was measured at 206
nm, peak areas were quantitated, and the percentage conver-
sion to product was used to calculate the percentage of control
cleavage in the presence of inhibitors. The 3′-cleavage and
integration activities of purified HIV-1 integrase were quan-
titated as previously described.46
1
solid: mp 160-161 °C; H NMR (300 MHz, CDCl3) δ 8.37 (d,
J ) 2.5 Hz, 2 H), 8.27 (d, J ) 1.86 Hz, 2 H), 4.07 (s, 6 H), 3.95
(s, 6 H); IR (neat) 3078, 2954, 1734, 1670, 1608, 1540 cm-1
Anal. (C19H16O7I2) C, H.
.
3′,3′′-Diiodo-4′,4′′-dim eth oxy-5′,5′′-bis(m eth oxycar bon yl)-
1,1-d ip h en yl-1-h ep ten e (44). NaN(TMS)2 (1 mL, 1 mmol)
was added to an ice cold suspension of hexyltriphenylphos-
phonium bromide (0.427 g, 1 mmol) in THF (20 mL), and the
solution was stirred for 30 min at 0 °C. A solution of the
benzophenone 43 (0.2 g, 0.33 mmol) in THF (5 mL) was added
to the preformed ylide, and the solution was stirred at room
temperature overnight. The mixture was partitioned between
1 N HCl (100 mL) and ethyl acetate (100 mL). The organic
layer was evaporated and flash chromatographed on silica gel
(50.0 g), eluting with hexanes-ethyl acetate (5:1). The frac-
tions which contained the product were pooled, evaporated,
and rechromatographed on silica gel (20 g), eluting with
hexanes-ethyl acetate (5:1), to give the product 44 (0.022 g,
9%) as an oil: 1H NMR (CDCl3, 300 MHz) δ 7.69 (s, 2 H), 7.54
(d, J ) 2.0 Hz,1 H), 7.52 (d, J ) 2 Hz, 1 H), 6.01 (t, J ) 7.6
Hz, 1 H), 3.93 (s, 3 H), 3.89 (s, 3 H), 3.88 (s, 3 H), 3.85 (s, 3 H),
2.05 (q, J ) 7.3 Hz, 2 H), 1.42 (m, 2 H), 1.25 (m, 2 H), 0.85 (t,
J ) 6.7 Hz, 3 H); IR (neat) 2953, 2929, 1742, 1738, 1731, 1713
cm-1; HRFABMS calcd for C25H28I2O6 m/z 677.9975 (M+), found
m/z 677.9954. Anal. (C25H28I2O6‚0.5EtOAc) C, H.
In Vitr o An ti-HIV Assa y. Anti-HIV screening of test
compounds against various viral isolates and cell lines was
performed as previously described.39 This cell-based microtiter
assay quantitates the drug-induced protection from the cyto-
pathic effect of HIV-1. Data are presented as the percent
control of XTT values for the uninfected, drug-free control.
EC50 values reflect the drug concentration that provides 50%
protection from the cytopathic effect of HIV-1 in infected
cultures, while the CC50 reflects the concentration of drug that
causes 50% cell death in the uninfected cultures. XTT-based
results were confirmed by measurement of cell-free superna-
tant reverse transcriptase and p24 levels. All XTT cytopro-
tection data were derived from triplicate tests on each plate,
with two separate sister plates. Thus, the EC50 value from
each plate represents the average of triplicates, and the two
EC50 values from sister plates were averaged. The variation
from the mean averaged less than 10%.
Mech a n istic Assa ys. The effects of inhibitors on the in
vitro activity of purified RT (kind gift of Steve Hughes, NCI-
FCRDC, Frederick, MD) were determined by measurement of
incorporation of [32P]TTP into the poly(rA)‚oligo(dT) (rAdT)
homopolymer or [32P]GTP into the poly(rC)‚oligo(dG) (rCdG)
template primer systems. After termination of reactions with
ice cold 10% trichloroacetate, samples were filtered through a
GF/C membrane under vacuum. Filters were then washed
with ethanol, and the level of radiolabel incorporation was
quantitated by Cernkov counting on a Packard Matrix 9600
direct beta counter. 3′-Azido-2′,3′-dideoxythymidine-5′-tri-
phosphate (AZTTP) and nevirapine served as positive controls
for inhibition of RT.
To determine if compounds affected the HIV-1 nucleocapsid
protein zinc fingers, fluorescence measurements of the Trp37
residue in the C-terminal zinc finger of the HIV-1 nucleocapsid
protein were performed as previously described.34,44 Recom-
binant nucleocapsid protein was prepared at 20 µg/mL in 10
mM sodium phosphate buffer (pH 7.0), treated with 25 µM of
test compound, then after indicated time intervals the samples
were diluted 1/10 in 10 mM sodium phosphate buffer (pH 7.0),
and the fluorescence intensity was measured. The excitation
and emission wavelengths utilized with the Shimadzu RF5000
spectrofluorimeter were 280 and 351 nm, respectively. The
analytical procedure employed to determine the reagent-
induced inhibition of HIV-1 protease activity has been previ-
ously described.45 Recombinant HIV-1 protease (Bachem
BioScience Inc., King of Prussia, PA) and the substrate (Val-
The attachment/fusion assay was performed as described
by Ciminale47 with modification. Briefly, HIV-1 envelope-
expressing, Tat-producing HL2/3 cells and CXCR-4 expressing,
LTR-â-Gal-containing MAGI cells (obtained from the AIDS
Research and Reference Program, National Institute of Allergy
and Infectious Disease, NIH, Bethesda, MD) were preincu-
bated separately with test compound for 1 h at 37 °C, followed
by admixture of the two cell lines at a cell ratio of 1:1.
Incubations were then continued for 16 h. The cells were then
fixed and stained for the expression of â-Gal with indolyl-â-
D-galactopyranoside (X-Gal) as described previously.48 The
number of blue cells (indicating completion of attachment and
fusion of membranes) were counted by light microscopy.
Tim e Cou r se Exp er im en ts. To identify the stage(s) of
HIV infection affected by ADAM II (22), the compound was
evaluated in a high MOI acute phase time of addition assay.
CEM-SS cells (105) were preincubated with HIVIIIB (MOI )
1.0) at 0-4 °C for 1 h to allow attachment of virus to cells but
not fusion or reverse transcription. Samples were then washed
three times with ice cold media to remove unbound virus, after
which the samples were rapidly warmed to 37 °C (at time zero,
to), allowing the infectious cycle to proceed. ADAM II (22) was
added to samples at to or at various times after warming to
37 °C (t ) 0.5, 1, 2, 4, 8, or 24 h postwarming). Dextran sulfate
(100 µg/mL) and nevirapine (1 µM) served as controls for
inhibitors of virus attachment and reverse transcriptase,
respectively. After a 24 h incubation, 5 × 103 cells from each
sample were placed in culture and analyzed after 48 additional
h for virion production by p24 antigen capture, as described
previously.39
Scr een in g Aga in st HIV-1 Vir u ses Con ta in in g NNRTI
Resista n ce Mu ta tion s. These studies were performed as
previously described.49
Ack n ow led gm en t. This investigation was made
possible by Grant RO1-AI-36624 and Contract NO1-CM-
17513, awarded by the National Institutes of Health,
DHHS. A.C.-G. wishes to thank Consejo Nacional de
Ciencia y Tecnologia (Mexico) for a scholarship and
Cytel Corporation for financial support. This research
was supported in part by the National Cancer Institute,
Contract NO1-C0-56000. The content of this publication
does not necessarily reflect the views or policies of the
Department of Health and Human Services, nor does
its mention of trade names, commercial products or
organizations imply endorsement by the U.S. Govern-
ment.
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