Design of non-nucleoside inhibitors of HIV-1 reverse transcriptase with improved drug resistance properties. 2

Article abstract of DOI:10.1021/jm040072r

HIV-1 nonnucleoside reverse transcriptase Inhibitors (NNRTIs) are part of the combination therapy currently used to treat HIV infection. The features of a new NNRTI drug for HIV treatment must include selective potent activity against both wild-type virus as well as against mutant virus that have been selected by use of current antiretroviral treatment regimens. Based on analogy with known HIV-1 NNRTI inhibitors and modeling studies utilizing the X-ray crystal structure of inhibitors bound in the HIV-1 RT, a series of substituted 2-quinolones was synthesized and evaluated as HIV-1 inhibitors.

Full text of DOI:10.1021/jm040072r

J. Med. Chem. 2004, 47, 5923-5936
5923
Design of Non-nucleoside Inhibitors of HIV-1 Reverse Transcriptase with
Improved Drug Resistance Properties. 2.
George A. Freeman,* C. Webster Andrews III, Andrew L. Hopkins,∞,‡ Gina S. Lowell,O Lee T. Schaller,
Jill R. Cowan, Stephen S. Gonzales,X George W. Koszalka,x Richard J. Hazen, Lawrence R. Boone,
Rob G. Ferris, Katrina L. Creech, Grace B. Roberts, Steven A. Short, Kurt Weaver, David J. Reynolds,
John Milton, Jingshan Ren,∆,∞ David I. Stuart,∆,∞ David K. Stammers,∆,∞ and Joseph H. Chan
GlaxoSmithKline Research and Development, 5 Moore Drive, Research Triangle Park, North Carolina 27709,
Division of Structural Biology, The Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive,
Oxford, OX3 7BN, UK, and Oxford Centre for Molecular Sciences, New Chemistry Building, University of Oxford,
South Parks Road, Oxford, OX1 3QT, UK
Received March 25, 2004
HIV-1 nonnucleoside reverse transcriptase inhibitors (NNRTIs) are part of the combination
therapy currently used to treat HIV infection. The features of a new NNRTI drug for HIV
treatment must include selective potent activity against both wild-type virus as well as against
mutant virus that have been selected by use of current antiretroviral treatment regimens.
Based on analogy with known HIV-1 NNRTI inhibitors and modeling studies utilizing the X-ray
crystal structure of inhibitors bound in the HIV-1 RT, a series of substituted 2-quinolones was
synthesized and evaluated as HIV-1 inhibitors.
Introduction
effectiveness in both drug-na¨ıve and drug-experienced
patients. Yet despite favorable antiviral potency against
a range of relevant NNRTI mutants, clinical resistance
to efavirenz eventually develops due primarily to the
K103N mutation. The presence of the K103N mutant
has indeed become its Achilles’ heel; it is the most
observed mutant in AIDS patients who failed treatment
with efavirenz.7-9
In the life cycle of HIV, the causative agent of AIDS,
one of the enzymes required for replication is the virally
encoded human immunodeficiency virus reverse tran-
scriptase (HIV RT). HIV RT converts single-stranded
RNA into double-stranded DNA that is ultimately
incorporated into the human genome.1 The utility of
HIV RT as a therapeutic target has been amply estab-
lished by the availability of drugs aimed at its inhibition.
Six nucleoside inhibitors (AZT, D4T, 3TC, FTC, ddI, ddC
and ABC), the recently FDA-approved nucleotide, teno-
fovir disoproxil fumarate (TDF), and three nonnucleo-
side reverse transcriptase inhibitors (NNRTIs) (nevi-
rapine,2 delavirdine3 and efavirenz4) all FDA-approved
drugs for the treatment of HIV infections, exert their
therapeutic efficacy by inhibiting HIV RT.
NNRTIs bind in a pocket approximately 10 Å away
from the catalytic site where nucleotides bind5 and are
generally specific for HIV-1 RT. Treatment of HIV
infection with NNRTIs has trailed behind nucleosides
because of rapid emergence of resistant strains of virus.
It was only after the success of combination therapy
with nevirapine in sustaining a viral load reduction that
a firm footing for NNRTIs was finally established.6
Efavirenz4 has set the standard for NNRTI therapy,
primarily because of its favorable antiviral profiles and
The ready availability of X-ray crystal structures of
inhibitor-HIV RT complexes, coupled with the abun-
dance of drug resistance data,10 has enabled us to
pursue a de novo approach to drug design. One aim of
the design was to study NNRTI interactions with the
inhibitor binding site and to identify a common phar-
macophore from the array of known structures upon
which a novel chemical structure (template) could be
built. Analogue synthesis would then provide an avenue
for the optimization of contacts with residues around
the binding pocket potentially leading to maximal
effectiveness against the wild-type virus and minimal
loss of potency should mutations occur. Of course, our
additional aim was to identify a template that was
amenable to synthesis so that we could construct a
structure-activity relationship (SAR) around the mol-
ecule. As mentioned in the preceding paper,11 the
common pharmacophore identified was that of structure
A shown in Figure 1. After consideration of several
possible templates, the quinolone as shown by structure
1 was chosen, which allowed for the incorporation of the
pharmacophore. Such a structure had the additional
benefit of feasibility of synthesis and amenability to
substituent variations.
* To whom correspondence should be addressed. Phone: 919-483-
2302. Fax: 919-483-6053. E-mail: Andy.A.Freeman@gsk.com.
∆ The Wellcome Trust Centre for Human Genetics, University of
Oxford.
∞ Oxford Centre for Molecular Sciences, New Chemistry Building,
University of Oxford.
‡ Current address: Molecular Informatics, Structure and Design,
Pfizer Global Research and Development, Sandwich, Kent, CT13 9NJ,
U.K.
We envisaged that an SAR could be established from
modifications of the R, R′ and R′′ groups in 1. Synthesis
of compounds 1a-d and their subsequent antiviral
results suggested that the quinolone scaffold was po-
tentially suitable to test our design hypothesis.11 We
now report the synthesis and SAR studies of additional
O Current address: Rush University, 600 S. Paulina St., Chicago,
IL 60610.
X Current address: Array Biopharma, 3200 Walnut Street, Boulder,
CO 80301
x Current address: Trimeris, Inc., Durham, NC.
10.1021/jm040072r CCC: $27.50 © 2004 American Chemical Society
Published on Web 10/23/2004

5924 Journal of Medicinal Chemistry, 2004, Vol. 47, No. 24
Freeman et al.
Compounds 1i and 1j were prepared according to
procedures shown in Scheme 2. Methyl 5-Chloroanthra-
nilate 5a and methyl 5-fluoroanthranilate 5b were first
acylated with ethoxyacetyl chloride to give intermedi-
ates 6a and 6b.13 Ring closure using potassium hexa-
methyldisilylamide in toluene gave quinolones 4q and
4r. This step was then followed by alkylation with
cyclobutylmethyl bromide using sodium hydride as the
base, resulting in 1i and 1j.
The synthesis of 1k began with isatoic anhydride 7,
which was reacted with ethyl cyanoacetate 8 to give
intermediate 9. Ring closure of 9 gave quinolone 4s,
which was alkylated with cyclobutylmethyl bromide
using sodium hydride as the base to give 1k. The series
of procedures are depicted in Scheme 3.
Figure 1. Common pharmacophore derived from the analysis
of known NNRTIs used as a basis for template design.11
analogues, which culminated in the identification of a
series of compounds that manifest a broad-spectrum
antiviral activity against a panel of clinically relevant
NNRTI resistant strains.
Results and Discussion
Chemistry. Quinolones 1a-h and 1l-aa were pre-
pared according to the procedures shown in Scheme 1.
Appropriately substituted anilines 2 were treated with
an excess of diethyl malonate and heated in diphenyl
ether to 250 °C for 24 h.12a,b Alkylation of the resulting
quinolones 4 with alkyl halides using sodium hydride
in DMF resulted in 1a-h, 1l-aa listed in Table 1.
Compounds 1bb, 1cc, 1ee-hh were prepared accord-
ing to procedures shown in Scheme 4. Quinolones 4c,
4d, 4e-g and 4t were allowed to react with 1-bromo-
2,2,2-trifluoroethane in the presence of sodium hydride
Scheme 1a
a Conditions: (a) (Ph)2O, 250 °C; (b) RX, NaH, DMF, 100 °C.
Scheme 2a
a Conditions: (a) EtOCH2COCl, Et3N, CH2Cl2; (b) KHMBS, toluene; (c) cyclobutylCH2Br, NaH, DMF.

Inhibitors of HIV-1 Reverse Transcriptase
Journal of Medicinal Chemistry, 2004, Vol. 47, No. 24 5925
Table 1. Antiviral Activity of Quinolinones 1a-hh against Wild-Type HIV-1 and Nevirapine-Resistant Strain in the MT4 Assay
IC50 value (nM) vs
compd
R
R′
R′′
HIV-1
Nev-R
CC50/IC50
1a
1b
1c
1d
1e
1f
1g
1h
1i
1j
1k
1l
1m
1n
1o
1p
1q
1r
1s
1t
1u
1v
1w
1x
1y
1z
1aa
1bb
1cc
1dd
1ee
1ff
1gg
1hh
6-Cl
6-Cl
6-F
6-F
6-F
6-Cl
6-F
6-Cl
6-F
6-Cl
H
n-propyl
n-propyl
methyl
cyclopropylCH2
cyclobutyl
1100
470
990
39
8300
2500
3900
230
>40000
>8000
>8000
>8000
>8000
>40000
>500
cyclobutylCH2
cyclobutylCH2
cyclobutylCH2
cyclobutylCH2
cyclobutylCH2
cyclobutylCH2
cyclobutylCH2
cyclobutylCH2
cyclobutylCH2
cyclobutylCH2
cyclobutylCH2
cyclopentyl
ethyl
n-propyl
n-propyl
isopropyl
isopropyl
ethoxy
ethoxy
cyano
n-propyl
n-propyl
n-propyl
n-propyl
n-propyl
n-propyl
ethyl
isobutyl
sec-butyl
n-propyl
n -propyl
n -propyl
n -propyl
n -propyl
isopropyl
n -propyl
ethyl
69
190
72
390
26
230
29
230
>500
470
290
>8000
>8000
1200
380
120
150
96
1070
2090
>8000
>8000
1800
3900
1700
1300
1700
1020
1600
290
>8000
>8000
>8000
>8000
>8000
>40000
>40000
>40000
>40000
>40000
>40000
>40000
>40000
>40000
>40000
>40000
>5000
>40000
>40000
>8000
>8000
>8000
16000
7-OCH3
6-F,5-NO2
H
6-Br
6-F
cyclopentyl
cyclopentyl
6-Cl
cyclopentyl
6-Cl
cyclopentyl
78
6-Cl
cyclopentyl
52
6-Cl
cyclopentyl
9
6-CH3
6-OCH3
6-OCF3
6-CN
6-Cl
cyclopentyl
970
1010
380
120
58
6400
24000
2500
2000
760
cyclopentyl
cyclopentyl
cyclopentyl
cyclohexyl
6-Cl
cyclohexyl
23
5100
25
72
109
29
24
150
17
360
6-Cl
cyclohexylCH2
cyclopropylethynyl
cyclopropylethynyl
cyclopropylethynyl
cyclopropylethynyl
cyclopropylethynyl
cyclopropylethynyl
sec-butylethynyl
1300
15
6-F
6-F
n-propyl
n-propyl
isopropyl
isopropyl
isobutyl
isopropyl
81
6-Cl
120
6-F
25
6-Cl
31
>8000
>8000
>6500
6-F
120
6-F
32
in DMF at 150 °C to give trifluoroethoxy intermediates
10a-e that were then protected with tert-butyldimeth-
ylsilyl chloride in DMF using triethylamine to give
intermediates 11. Reaction with cyclopropylethynyl-
lithium gave alkynes 12.15 Deprotection of 12 was
accomplished with Dowex 50 acidic resin in a mixture
of THF and methanol at room temperature providing
the desired 1bb, 1cc, 1ee-gg. Compound 1hh was
synthesized using the same procedure, except in this
case, the lithium salt of 3-methylpentyne was used.
Finally, compound 1dd was prepared according to
procedures similar to those shown in Scheme 4. As
shown in Scheme 5, compound 10e, which was prepared
according to the procedure described above, was pro-
tected with p-methoxybenzyl chloride.16 The resultant
intermediate 11 was then reacted with cyclopropyleth-
ynyllithium to give compound 12. Deprotection with
ammonium cerium nitrate gave 1dd.17
Biology. We decided, as an initial task, to categorize
the synthesis of the quinolone analogues into four
subgroups where the R′′ moieties were made up of
cyclopropylethynyl, cyclobutylmethyl and cyclopentyl
groups (see Figure 3). As synthesis progressed, ad-
ditional four substituents were investigated, although
in a limited sense, which was designed to extend our
understanding of the binding of these quinolone ana-
logues. These were the cyclohexyl, sec-butylethynyl,
cyclopropylmethyl, cyclobutyl and cyclohexylmethyl.
Within the subgroups consisting of the above substit-
uents, variations were then made around the R and R′
groups in rings A and B, of 1, respectively (Figure 2a).
The R group included mainly the fluoro and chloro
substituents. On the basis of the modeling work, the
NH proton was expected to form a hydrogen bond with
the backbone carbonyl group of the K103 residue,
similar to that of efavirenz. Therefore, differences in the
electron-withdrawing properties of the R substituents
were expected to have an effect on the acidity of the NH
proton and thus the strength of the hydrogen bond. As
shown in Table 1, other R substituents, intended to
answer certain SAR questions, were also included.
As for the R′ group, we focused mainly on the
isopropyl and n-propyl substituents. These were the
groups that were viewed to be the optimal from the
design work. Other substituents were also included,
primarily to confirm our understanding of the activities
of the analogues having the n-propyl and isopropyl
groups. The antiviral and enzyme inhibition data for
all synthesized compounds are summarized in Tables
1 and 2.
The compounds were initially assayed in a MT4 cell
infection model with wild-type HIV-1 and mutant

5926 Journal of Medicinal Chemistry, 2004, Vol. 47, No. 24
Freeman et al.
Scheme 3a
a Conditions: (a) Et3N, DMF, 150 °C; (b) cyclobutylCH2Br, NaH, DMF.
Scheme 4a
a Conditions: (a) BrCH2CF3, NaH, DMF, 150 °C; (b) TBDMSCl, Et3N, DMF, RT; (c) cyclopropylethynyllithium, sec-BuLi, Et2O, -78 °C
to RT; (d) Dowex 50 H+, THF, MeOH, RT.
strains of HIV-1.18 Using an arbitrary IC50 cutoff value
of e300 nM, 24 compounds were found to fall at or below
the cutoff against the wild-type virus and eleven against
the nevirapine resistant strain (Nev-R), which contains
the mutation Y181C in the HIV-1 RT gene. The data
from the list of compounds in Table 1 suggested the
following: for the R group in template 1, fluoro and
chloro groups appeared to be optimal for antiviral
activity. Conversely, moieties such as methyl and meth-
oxy led to compounds (1u and 1v) that showed much
reduced antiviral activity. The C6 position appeared to
be optimal as evidenced from the lack of antiviral
activity of compound 1l (with 7-methoxy group) com-
pared to compound 1v (with 6-methoxy group). For the
R′ group, variations between ethyl, n-propyl, isopropyl
and isobutyl did not appear to have a striking difference
in antiviral activity, provided that the optimal groups
were used in R. Even an ethoxy group was well tolerated
(compounds 1i and 1j), although both compounds were
more active against the wild-type virus than against the
Nev-R strain. This is in direct contrast to what was
found in our modeling work, which suggested that
isopropyl and n-propyl groups would impart optimal
antiviral activities.
The cyclopropylethynyl subgroup had the largest
number of active compounds (1bb-gg). All six com-
pounds within this subgroup showed antiviral activity
against both the wild type and the Nev-R strains that
were much less than the cutoff IC50 value of e300 nM.
Indeed, compounds 1ee and 1ff were two of the most
potent analogues against both strains. Undeniably, the
cyclopropylethynyl moiety imparted the antiviral po-
tency since the corresponding analogues in the other
subgroups (see compounds 1a, 1g, 1h) were less active.
The cyclopropylethynyl motif was favorably exploited
in the 1,4-dihydro-2H-3,1-benzoxazin-2-one work that
culminated in the FDA-approved efavirenz.19 In fact, our
modeling suggested that when quinolone 1ee and
efavirenz were superimposed in the NNRTI binding
pocket, the cyclopropylethynyl moiety for both com-
pounds projected into a common subpocket defined by
the Y181 and Y188 residues. Because the electronic
properties of the fluoro group are markedly different
from the chloro group (σ values of 0.06 and 0.23,

Inhibitors of HIV-1 Reverse Transcriptase
Journal of Medicinal Chemistry, 2004, Vol. 47, No. 24 5927
Scheme 5a
a Conditions: (a) BrCH2CF3, NaH, DMF, 150 °C; (b) ClCH2Ph(p-OMe), Ag2O, DMF; (c) cyclopropylethynyllithium, sec-BuLi, Et2O, -78
°C to RT; (d) (NH4)2Ce(NO3)6, CH3CN, H2O.
to virus strains encoding the K103N and the Y181C
mutations, resistance to nevirapine is also due to strains
encoding the G190A, Y188C and the V106A mutations,
and the P236L mutation in the case of delavirdine.22
Again, using an arbitrary IC50 value cutoff of e300
nM, almost the same number of compounds active
against the wild-type and Y181C strains were identified
as that in the MT4 assay. Twenty-eight compounds were
active against the G190A strain and twenty-seven
against the Y188C mutant. The compounds generally
showed weak activity against the K103N strain with
only two compounds (1d and 1z) showing IC50 values
of <300 nM against the K103N resistant strain. Simi-
Figure 2. (a) Quinolone template incorporating NNRTI
larly, the activity against strains containing two muta-
pharmacophore A. SAR determined from modification of
tions was lacking, except for compounds 1bb, 1dd, 1ee,
1ff and 1hh. Five compounds (1dd, 1ee, 1ff, 1f, and
1q) were active against the V106A strain.
substituents R, R′ and R′′. (b) Initial quinolone leads.11
respectively,20 we expected that the acidity of the NH
proton would be stronger for compound 1ff, and thus
its hydrogen bond capability to the backbone carbonyl
group of the K103 residue, than for compound 1ee.
Nonetheless, compounds 1ff and 1ee showed equipo-
tency against the wild-type virus. In fact, this equipotent
tendency was observed in the rest of the analogues with
similar R′ and R′′ substitutents (see Table 1), suggesting
therefore that antiviral potency was not dependent on
the strength of the hydrogen bond between NH of the
quinolone analogues and the K103 backbone carbonyl
group.
After the initial determination of antiviral activity,
the compounds were further assayed against a panel of
recombinant, isogenic viruses21 containing the wild type
HIV-1 and NNRTI resistant strains encoding the fol-
lowing single and double mutations: K103N, V106A,
G190A, Y188C, V108I, Y181C, K103N/Y181C, K103N/
G190A, V106A/Y181C, K103N/V108I, and V108I/Y181C.
These mutations occur in the binding site where the
NNRTIs come in close contact with and are generally
associated with NNRTI-treatment failures.
As was found in the MT4 assay, the active compounds
came mainly from the cyclopropylethynyl subgroup. In
fact, broad-spectrum activity against the panel of mu-
tants was seen among analogues within this subgroup.
Among them, compound 1bb was the most broad-
spectrum in its antiviral activity, and was then followed
by compounds 1dd, 1ee and 1ff. However, in general,
compounds 1ee and 1ff had higher potency.
As alluded to above, for an NNRTI to be considered
truly effective, particularly among drug-experienced
patients, the compound needs to be able to overcome
the cross-resistance barrier imposed by the K103N and
the Y181C mutations and to be active against mutants
insensitive to currently available drugs. As shown in
the bar diagram of Figure 4, efavirenz was generally
potent against key NNRTI resistant strains listed in
Table 2, which thus makes it currently the most
effective NNRTI in the market. On the other hand,
nevirapine and delavirdine did not generally fare well
against the same set of resistant strains. When com-
pared with nevirapine, delavirdine and efavirenz, a few
of the quinolone analogues such as 1ee and 1ff (see
Figure 4) were more broad-spectrum in their antiviral
activities than nevirapine and delavirdine and were
quite similar to that of efavirenz. Additionally, both
It is now known that the most common mutations
that manifest high cross-resistance to a vast array of
NNRTIs are the K103N and the Y181C while other
mutations are generally compound specific. In addition

5928 Journal of Medicinal Chemistry, 2004, Vol. 47, No. 24
Freeman et al.
Table 2. Antiviral Activity of Quinolones 1a-1hh and Standards against Wild Type HIV-1 and Those Containing NNRTI-Resistance
Mutations in HeLa-CD4 MAGI Assay
K103N/ K103N/ V106A/ K103N/ V108I/
R
R′
R′′
WTRVA
120
K103N V106A G190A Y188C V108I Y181C Y181C G190A Y181C V108I Y181C
1a 6-Cl
n-propyl cyclopropyl-
methyl
>2000
630
49
89
200
210 >2000 >2000 >2000 >2000
1700
1b 6-Cl
1c 6-F
n-propyl cyclobutyl
methyl cyclobutyl-
methyl
300
610
>2000 >2000
>2000 >2000
220
250
290
690
1700 >2000 >2000 >2000 >2000 >2000
>2000 >2000 >2000 >2000 >2000 >2000
840 1700
1d 6-F
1e 6-F
1f 6-Cl
1g 6-F
1h 6-Cl
1I 6-F
1j 6-Cl
ethyl
cyclobutyl-
methyl
89
63
270
1800
980
1700
1700
124
110
46
15
16
9
130
60
250
290
77
390 >2000
1100 >2000 >2000
870
560
600
700
440
n-propyl cyclobutyl-
methyl
n-propyl cyclobutyl-
240 >2000 >2000
1700 >2000
630 >2000
36
16
>2000 >2000
280 >2000
210 >2000
1300
methyl
isopropyl cyclobutyl-
methyl
isopropyl cyclobutyl-
49
1700
560
1900
380
30
440
79
530 >2000 >2000
560 1900 >2000
15
32
methyl
cyclobutyl-
methyl
cyclobutyl-
methyl
cyclobutyl- >2000
methyl
ethoxy
ethoxy
cyano
580
340
>2000 >2000
>2000 >2000
86
170
360 1500
390 890
>2000 >2000 >2000 >2000 >2000 >2000
>2000 >2000 >2000 >2000 >2000 >2000
>2000 >2000 >2000 >2000 >2000 >2000
>2000 >2000 >2000 >2000 >2000 >2000
1k
H
>2000 >2000 >2000 >2000 >2000
>2000 >2000 >2000 >2000 >2000
1l 7-CH3O n-propyl cyclobutyl- >2000
methyl
1m 6-F,
5-NO2
n-propyl cyclobutyl-
1100
>2000 >2000
>2000 >2000
>2000
>2000 >2000
>2000 270
>2000 >2000
>2000 1500
540
250 ∼1000
>2000 >2000 >2000
1000 >2000 >2000
methyl
1n
H
n-propyl cyclopentyl
n-propyl cyclopentyl
n-propyl cyclopentyl
n-propyl cyclopentyl
350
49
150
60
72
150
9.3 (900)
400
420
270
65
32
38
270
32
370
25
12
42
180 1220
630 >2000 >2000 >2000 >2000 >2000
>2000 >2000 >2000 >2000 >2000 520
1800 >2000 >2000 >2000 >2000 >2000
1o 6-Br
1p 6-F
1q 6-Cl
1r 6-Cl
1s 6-Cl
1t 6-Cl
1u CH3
1v 6-CH3O n-propyl cyclopentyl
1w 6-CF3O n-propyl cyclopentyl
1x 6-CN
1y 6-Cl
1z 6-Cl
1aa 6-Cl
430
9
42
31
54
59
120
350
200
260
280
>2000 >2000 >2000 >2000 >2000
>2000
640 ∼1000 >2000
37 >2000 >2000 >2000 >2000
670
780
1100
ethyl
cyclopentyl
6
isobutyl cyclopentyl
sec-butyl cyclopentyl
n-propyl cyclopentyl
970 >2000 ∼2000
670 1100
320 >2000 >2000 ∼2000 >2000 >2000
410 >2000 >2000 >2000 >2000 >2000
710 >2000 >2000 >2000 >2000 >2000
990 >2000 >2000 >2000 >2000 >2000
1700 >2000 >2000 >2000 >2000 >2000
>2000 >2000
>2000 >2000
>2000 >2000
150
710
47
240
160
360
52
710
540
300
240
180
110
n-propyl cyclopentyl
n-propyl cyclohexyl
isopropyl cyclohexyl
n-propyl cyclohexyl-
methyl
>2000
>2000
170
1300
980
1
54
12
470 >2000
1400 >2000
1000
190
1100 ∼2000
900
∼800
1000
1100
27
12
430 >2000
1200
>2000 >2000
260
23 >2000
690 >2000 >2000 >2000 >2000
1bb 6-F
1cc 6-F
1dd 6-Cl
1ee 6-F
1ff 6-Cl
1gg 6-F
1hh 6-F
ethyl
cyclopropyl-
ethynyl
25
66
420
>2000
>2000
400
340
440
220
150
57
6
21
15
5
100
60
160
60
24
1
300
1400
1800
620
68
490
300
100
52
230
240
130
370
230
11
n-propyl cyclopropyl-
ethynyl
n-propyl cyclopropyl-
290
70
380 >2000
38
92
15
39
120
220
120
660
1400
720
ethynyl
isopropyl cyclopropyl-
ethynyl
isopropyl cyclopropyl-
10
23
26
16
320
3
18
36
620
1200
1900
120
240
140
ethynyl
isobutyl cyclopropyl-
ethynyl
isopropyl sec-butyl-
130
28
>2000 >2000
16
21
220
21
230
110
150 >2000 1800
540
420
84
2
640
230
130 >2000
ethynyl
efavirenz
delavirdine
neviripine
1
159
89
23
2651
1
870
7
35
1
124
1.4
97
340 >10000 >50000
43
552
3
74
3
1250 8000
10000
3400
10000
7100 ∼10000 >10000 2200
- >10000 21000 >10000
Figure 4a. We have reported the structures of four RT-
quinolone complexes (RT-2a, RT-2b, RT-5, and RT-6;
Hopkins et al., preceding paper). Comparing the protein
core of 110 residues around the NNRTI site of RT-
GW490745X with those of RT and quinolone analogue
complexes more than 87% of the CA atoms can be
overlapped with rms deviations of 0.56 Å, 0.57 Å, 0.55
Å and 0.56 Å, respectively. The chemical differences
between the inhibitors result in slight alterations in the
binding modes at the NNRTI site, which are accom-
modated by conformational changes in the protein,
mainly in side-chains but also to a lesser extent in the
main-chain (Figure 4b). GW490745X has a cyclopropy-
lethynyl group instead of the cyclohexyloxy or cyclo-
hexylthio of other quinolone analogues (Hopkins et al.,
preceding paper). A result of this differing substituent
is that GW490745X binds in a significantly different
Figure 3. R′′ substituents used in the synthesis of analogues
of 1.
analogues were generally more potent than nevirapine
and delavirdine, but fell short of the potency of efavirenz.
Crystallography. Comparison of RT-GW490-
745X (1ee) with other RT-Quinolone Complexes.
GW490745X bound at the NNRTI site is shown in

Inhibitors of HIV-1 Reverse Transcriptase
Journal of Medicinal Chemistry, 2004, Vol. 47, No. 24 5929
Figure 4. Stereodiagrams showing the NNRTI binding site. (a) 1ee at the NNRTI site. The CA backbone of the protein is draw
as ribbons and coils and colored in blue, and protein side-chains are shown as red sticks. The inhibitor is shown as ball-and-stick
representation and colored by atoms. The simulated annealing omit electron density map for the inhibitor contoured at 3.5σ is
shown as semi-transparent green surface. The yellow broken stick represent the hydrogen bond between the carbonyl oxygen of
residue K101 and the inhibitor. (b) comparison of the NNRTI sites between RT-1ee and RT-2b complexes. The protein CA
backbones and side-chains are shown as thinner and thicker sticks with RT-1ee and RT-2b colored in orange and blue,
respectively. The inhibitors are shown as ball-and-sticks with 1ee colored in red and 2b in cyan. (c) Comparison of the NNRTI
sites in RT-1ee and RT-efavirenz complexes. The drawing scheme is the same as b) with RT-1ee colored in orange and red,
and RT-efavirenz in blue and cyan.
position and orientation compared with 2b. GW490745X
shifts about 1 Å toward V179, with the quinolone ring
tilted by some 10° and the isopropyl group rotated about
180°. To avoid a clash with the isopropyl group of the
inhibitor the side-chain of V179 is rotated by 120°. The
cyclopropylethynyl group is positioned more distantly
from Y188 and hence has fewer contacts with this
residue. There is a more than 0.5 Å main-chain move-
ment at residues 98-101 such that a similar H-bond
distance from the inhibitor to the carbonyl oxygen is
maintained (2.64 Å, 2a:2.55 Å, 5:2.67 Å, 6:2.81 Å, 2b:
2.78 Å). The position and smaller size of the fluorine
atom of GW490745X (chlorine in the other quinolones)
also introduces changes at the â10-â11 loop whose
flexible nature allows for the NNRTI site to accom-
modate inhibitors very different in size.26,29 The confor-
mation difference of the W229 side-chain can be attrib-
uted to the difference in unit cell for the crystals.30
Comparison of RT-GW490745X and RT-Efavi-
renz Complexes. 92 out of 110 CA atoms of the protein
core around the NNRTI site of RT-GW490745X can be
superimposed on that of RT-efavirenz31 with an rms
deviation of 0.44 Å. The quinolone ring of GW490745X
is tilted by about 10° from the benzoxazin-2-one ring of
efavirenz such that the fluorine end of the quinolone
ring is positioned about 0.5 Å higher and also drags

5930 Journal of Medicinal Chemistry, 2004, Vol. 47, No. 24
Freeman et al.
V106 with it (Figure 4c). The cyclopropyl group of
GW490745X is positioned higher up in the site due to
its extra oxygen atom, thereby making more interac-
tions with W229. The isopropyl group is positioned
closer to V179, about 1.5 Å offset from the structurally
related trifluoromethyl group of efavirenz which oc-
cupies the so-called “Tyrosine 181 trigger” position.26
The H-bond from the ring NH to the carbonyl oxygen
of K101 is shorter (2.64 Å) than that of RT-efavirenz
(2.72 Å). There are also differences in protein side-chain
conformation when comparing the two complexes, for
example at residues V106, V179, Y181 and L234 (47°
difference in the ø2 angle of Y181; 1.6 Å distance
between the CG1 atoms of V179).
Structure and Antiviral Activity Relationship.
The differences in position and orientation between RT-
GW490745X (1ee) and the four other quinolone com-
pounds in the NNRTI pocket can be attributed to the
substitution of the cyclohexyloxy or cyclohexylthio by a
cyclopropylethynyl group in 1ee. Indeed the cyclopro-
pylethynyl group is positioned much closer to cyclopro-
pylpropynyl group of efavirenz. Crystal structures of
complexes of RT with potent NNRTIs invariably have
a substituent that occupies the same volume as filled
by the trifluoromethyl group of efavirenz (Figure 4c).26,32
Interestingly, although the trifluoromethyl is at the
4-position on the benzoxazin-2-one ring of efavirenz and
is perpendicular to the ring plane, for 1ee the isopropyl
group fulfills this role but is in the 3-position of the
quinolone and in the plane of the ring. Thus it is
probably the tendency of the isopropyl group to occupy
the “Tyrosine 181 trigger” volume that tilts the quino-
lone ring compared to the benzoxazin-2-one ring of
efavirenz. Despite this, 1ee has higher spatial overlap
with efavirenz in the NNRTI pocket compared to the
other four quinolone analogues, which explains its
better antiviral activity. There are less hydrophobic
interactions from the smaller cyclopropylethynyl group
of 1ee to Y181 and Y188 compared to the cyclohexyloxy
or cyclohexylthio groups of the four other quinolone
analogues, explaining the smaller reduction of the
antiviral activity due to Y181C or Y188C mutation.
The details of NNRTI binding derived from the crystal
structures of the quinolone analogues correlate well
with the SAR data (Table 1). The isopropyl group of 1ee
forms strong van de Waals interactions with V179.
Replacement of the group with ethyl (1bb) or n-propyl
(1cc) would either reduce the hydrophobic interactions
or introduce structural clashes, therefore weakening the
antiviral activity (Table 2). A larger group such as
isobutyl (1gg) would reposition or reorient the inhibitor
in the NNRTI pocket, resulting in significant loss of
activity. The 6-fluoro group has a close contact (3.3 Å)
with the CB atom of residue L234, a larger Cl substitute
(1ff) would position the quinolone ring closer to the
benzoxazin-2-one ring of efavirenz as well as to V106.
That 1ff has higher activity against the V106A mutant
virus is probably because A106 would be able to move
closer to the inhibitor, partially compensating the loss
of protein-inhibitor interactions in the mutant struc-
ture. 1ee and efavirenz have a very similar spectrum
of activity against V108I, Y181C and Y188C mutant
viruses, which is reflected in the crystal structures
where the two inhibitors have similar interactions with
these residues. The G190A mutant virus is 6-fold less
sensitive to efavirenz, but 2-fold more sensitive to 1ee
compared to wild-type virus. The trifluoromethyl group
of efavirenz makes several hydrophobic contacts with
G190, while 1ee has no interaction with this residue,
the closest approach to the CA atom of G190 is 5.1 Å.
There is enough room for an alanine side-chain between
the quinolone ring and G190, and the G190A mutation
would be predicted to give greater protein-inhibitor
interaction and increase the tightness of inhibitor
binding.
Conclusions
We selected compound 1ee for further evaluation of
its druglike properties. The pharmacokinetic properties
of compound 1ee showed acceptable parameters includ-
ing clearance, half-life and oral bioavailability, 44 mL/
min/kg, 3.7 h, and 34% respectively. The therapeutic
index based on the ratio of the IC50 values of the MT4
cell lines versus the IC50 value against the wild-type
virus and Nev-R was >4000. In the MT4 assay, com-
pound 1ee showed an approximately 8-fold decrease in
wild-type IC50 value in the presence of 45% human
serum and a 2-fold decrease in the presence of 15% fetal
calf serum.
In summary, we have shown that, based on known
crystal structures and resistance data, a quinolone
template was designed, and synthesis led to a group of
analogues with a broad spectrum of activity against both
wild-type HIV-1 and key NNRTI-relevant mutant vi-
ruses. Analogues 1ee and 1ff demonstrated the most
broad-spectrum activity among these analogues and
were more potent than nevirapine and delavirdine
against mutant viruses that generally are insensitive
to currently known NNRTIs. The quinolone class of
NNRTIs, as predicted by their design, have proven to
be effective and potent against a wide range of diverse
drug resistant mutants, far more so than the first
generation NNRTIs. However, in the range of analogues
reported here, we did not improve upon the potency of
efavirenz, particularly in comparison with their activity
against the K103N strain. In conclusion, we believe the
data presented here justifies our initial assumption that
the structural analysis of the binding modes and drug
resistant mechanisms of NNRTIs can lead to valuable
insights to aid the design of the next generation of non-
nucleoside inhibitors of HIV-1 reverse transcriptase.
The principles established in our previous paper11 and
demonstrated here for the quinolone series may also be
applicable to other potential NNRTI templates to guide
the search for inhibitors with improved drug resistance
properties.
Experimental Section
Compound Synthesis. 6-Chloro-4-hydroxy-3-propyl-
2(1H)-quinolinone (4a). 4-Chloroaniline (2b) (10 g, 80 mmol)
and 3a (16 mL, 80 mmol) were combined in phenyl ether (100
mL) and heated to 250° overnight. The reaction was cooled to
50 °C. A precipitate formed and was collected by filtration.
After washing with hexane, 15 g (84%) of 4a was obtained as
a solid, which was used without further purification. 1H NMR
(Me2SO-d6) δ 11.3 (bs, 1H, OH), 10.0 (bs, 1H, NH), 7.82 (s,
1H, ArH), 7.44 (d, 1H, ArH), 7.21 (d, 1H, ArH), 2.5 (m,
overlapping with DMSO), 1.40 (m, 2H, CH2), 0.86 (t, 3H, CH3).
MS (ES+): m/z 238.0 (M + 1).

Inhibitors of HIV-1 Reverse Transcriptase
Journal of Medicinal Chemistry, 2004, Vol. 47, No. 24 5931
6-Chloro-4-cyclopropylmethoxy-3-propyl-2(1H)-quino-
linone (1a). Intermediate 4a (0.50 g, 2.1 mmol) was dissolved
in DMF (Aldrich, Sure Seal, 6 mL). Sodium hydride (0.126 g,
3.2 mmol, 1.5 equiv) was added and the solution stirred for
30 min. The reaction was placed in a 100 °C oil bath and
stirred for 5 min. Bromomethylcyclopropane (1 mL, 10.5 mmol,
5 equiv) was added and the reaction heated for 2 h. The
reaction was poured into ice-water (100 mL). The product was
extracted with ethyl acetate (1 vol), dried with magnesium
sulfate and filtered. The crude product was purified by flash
column chromatography on silica gel eluted with hexane/ethyl
acetate (3:1, v/v) followed by recrystallization from ethyl
dropwise via a syringe, followed by the addition of a catalytic
amount of DMF (1 drop). The reaction mixture was allowed
to stir at room temperature for 18 h. When judged complete,
the mixture was concentrated under reduced pressure to
provide ethyl 2-(chlorocarbonyl)butanoate (0.95 g, >100%) as
an orange oil, which was dissolved in CH2Cl2 and added
dropwise via an addition funnel to a solution of 2b (1.9 mL,
2.2 g, 20 mmol) and Et3N (10 mL, 7.3 g, 73 mmol) in CH2Cl2
(100 mL). The resultant mixture was allowed to stir at RT.
When judged complete, the reaction mixture was partitioned
between EtOAc and water. The organic layer was separated,
dried (MgSO4), filtered and concentrated under reduced pres-
sure to afford ethyl 2-[(4-fluoroanilino)carbonyl]butanoate (4.0
g, 80%) as a crystalline solid. This solid was dissolved in
phosphorus pentoxide methanesulfonic acid (PPMA) (70 mL,
(Cho, H.; Matsuki, S. Heterocycles 1996, 43 (1), 127-131) and
heated to 170 °C for 1 h. The mixture was allowed to cool to
room temperature and then poured over ice and filtered. The
filtrate was extracted with EtOAc, dried (MgSO4), filtered, and
concentrated under reduced pressure to a yellow solid. The
crude product was dissolved in 0.5 N NaOH, extracted with
toluene and acidified to pH∼3 using concentrated HCl. The
resulting white precipitate was filtered and dried to provide
1
acetate giving 1a (0.185 g, 30%). H NMR (Me2SO-d6) δ 11.8
(bs, 1H, NH), 7.70 (s, 1H, ArH), 7.53(d, 1H, ArH), 7.33 (d, 1H,
ArH), 3.88 (m, 2H, CH2), 2.53 (overlap DMSO, 2H), 1.5 (m,
2H, CH2), 1.40 (m, 1H, CH), 0.95 (t, 3H, CH3), 0.62 (m, 2H,
CH2), 0.36 (m, 2H, CH2). MS (ES+): m/z 292.0 (M + 1).). Anal.
(C16H18ClNO2) C, H, N, Cl.
6-Chloro-4-(cyclohexyloxy)-3-propyl-2(1H)-quino-
linone (1y). Intermediate 4a (2.50 g, 10.5 mmol), cyclohexyl
bromide (2.6 mL, 21 mmol), potassium carbonate (1.6 g, 46
mmol) and triethylamine (1.05 mL, 14 mmol) were combined
in DMF (Aldrich, Sure Seal, 50 mL) and heated in a 165 °C
oil bath for 36 h. The reaction was poured into ice-water (200
mL). The product was extracted with ethyl acetate (1 vol.),
dried with magnesium sulfate and filtered. The crude product
was purified by chromatography on silica gel eluted with
hexane/ethyl acetate (3:1, v/v) giving 1y (0.03 g, 1%). 1H NMR
(Me2SO-d6) δ 11.8 (bs, 1H, NH), 7.62 (s, 1H, ArH), 7.49 (d,
1H, ArH), 7.28 (d, 1H, ArH), 3.95 (m, 1H, CH), 1.95 (m, 2H,
CH2), 1.70 (m, 2H, CH2), 1.50 (m, 2H, CH2), 1.28-1.20 (m, 10H,
alkyls). MS (ES+): m/z 320.0 (M + 1).
1
4c (1.3 g, 43%) as a white solid. H NMR (Me2SO-d6) δ 11.37
(s, 1H), 7.62 (d, 1H), 7.32 (m, 2H), 2.58 (q, 2H), 1.02 (t, 3H).
4-(Cyclobutylmethoxy)-3-ethyl-6-fluoro-2(1H)-quinoli-
none (1d). To NaH (35 mg of 60% dispersion in oil, 0.87 mmol)
in a round-bottom flask equipped with a stir bar and nitrogen
on demand was added anhydrous DMF (5 mL). A solution of
4c (0.15 g, 0.72 mmol) in anhydrous DMF (1 mL) was added
dropwise, followed by the dropwise addition of (bromomethyl)-
cyclobutane (0.10 g, 0.07 mL, 0.65 mmol), and the reaction was
allowed to stir at room temperature for 48 h. The reaction
mixture was quenched by the dropwise addition of water and
extracted with ethyl acetate. The organic layer was separated,
dried (MgSO4), filtered, and concentrated under reduced
pressure to afford a yellow oil. The crude product was filtered
through a pad of silica gel, eluding with CH2Cl2, and the
filtrate was concentrated in vacuo. The solid was rinsed with
Et2O, and filtered to provide 1d (20 mg, 10%) as a white solid.
1H NMR (Me2SO-d6) δ 11.77 (s, 1H), 7.37 (m, 3H), 4.00 (d, 2H),
2.88 (m, 1H), 2.58 (q, 2H), 2.15 (m, 2H), 1.95 (m, 4H), 1.02 (t,
3H). MS (ES) 274 (M - H)-.
6-Chloro-4-(cyclobutyloxy)-3-propyl-2(1H)-quino-
linone (1b). The title compound was prepared from 4a by the
method used in the synthesis of 1y, except the reaction was
heated in a 70 °C oil bath for 7 h. Sodium hydride (0.04 g)
was then added and the reaction heated in a 120 °C oil bath
for 24 h. 1b (27% yield) was obtained following recrystalliza-
1
tion from ethyl acetate. H NMR (Me2SO-d6) δ 11.8 (bs, 1H,
NH), 7.56 (s, 1H, ArH), 7.53 (d, 1H, ArH), 7.32 (d, 1H, ArH),
4.46 (m, 1H, OCH), 2.5 (m, overlapping with DMSO), 2.3 (m,
3H, alkyls), 1.7 (m, 1H, alkyl), 1.50 (m, 4H, CH2), 0.95 (t, 3H,
CH3). MS (ES+): m/z 292.0 (M + 1). Anal. (C16H18ClNO2) C,
H, N, Cl.
6-Fluoro-4-hydroxy-3-propyl-2(1H)-quinolinone (4d).
The title compound was prepared from 2b and 3a by the
method used in the synthesis of 4a. A 56% yield of 4d was
6-Fluoro-4-hydroxy-3-methyl-2(1H)-quinolinone (4b).
The title compound was prepared according to the procedure
used in the synthesis of 4a starting from 2b (71.6 mmol, 7.95
g) and 3b (164 mmol, 28.54 g) to give 4b (9.8 g, 71%) as a
white solid. 1H NMR (Me2SO-d6) δ 11.38 (s, 1H), 10.19 (s, 1H),
7.55 (dd, 1H, J ) 2.9, 9.9 Hz), 7.39-7.22 (m, 2H), 2.04 (d, 0.5H,
J ) 1.8 Hz), 1.96 (s, 2.5H). MS (ES+): m/z 194 (M +1),
4-Cyclobutylmethoxy-6-fluoro-3-methyl-2(1H)-quino-
linone (1c). The title compound was prepared from 4b by the
method used in the synthesis of 1y except the oil bath
temperature was 70 °C and the reaction time was 24 h. 1c
(9% yield) was isolated by chromatography on silica gel eluted
with CHCl3/MeOH (95/5). 1H NMR (Me2SO-d6) δ 12.3 (bs,1H,
NH), 7.44-7.41 (m, 2H, ArH), 7.24-7.19 (m,1H, ArH), 4.01
(d, 2H, OCH2), 2.9 (m, 1H, CH), 2.2 (m, 5H, alkyls), 2.0 (m,
4H, alkyls). MS (ES+): m/z 262.0 (M + 1). Anal. (C15H16FNO2)
C, H, N, F.
3-Ethyl-6-fluoro-4-hydroxy-2(1H)-quinolinone (4c). To
a round-bottom flask equipped with a stir bar, an addition
funnel and nitrogen on demand was added 3c (5.0 mL, 5.0 g,
27 mmol). A solution of KOH (1.8 g, 32 mmol) in absolute
ethanol (50 mL) was added dropwise via an addition funnel,
and the reaction was allowed to stir at room temperature for
18 h. The reaction mixture was concentrated under reduced
pressure and the resultant crude solid washed with Et2O (30
mL) and concentrated again under reduced pressure to afford
potassium 2-(ethoxycarbonyl)butanoate (1.0 g, 95%) as a white
solid. This butanoate was dissolved in CH2Cl2 in a round-
bottom flask equipped with a stir bar and nitrogen on demand.
Oxalyl chloride (0.44 mL, 0.64 g, 5.0 mmol) was added
1
obtained. H NMR (MesSO-d6) δ 11.3 (bs, 1H, OH), 10.0 (bs,
1H, NH), 7.87 (d, 1H, ArH), 7.42 (dd, 1H, ArH), 7.22 (d, 1H,
ArH), 2.5 (m, overlapping with DMSO), 1.40 (m, 2H, CH2),
0.86 (t, 3H, CH3), MS (ES+): m/z 222.0 (M + 1).
4-Cyclobutylmethoxy-6-fluoro-3-propyl-2(1H)-quinoli-
none (1e). The title compound was prepared from 4d and
cyclobutylmethyl bromide by the method used in the synthesis
of 1y except the oil bath temperature was 60 °C. A 40% yield
of 1e was obtained. 1H NMR (Me2SO-d6) δ 11.8 (bs, 1H, NH),
7.32 (m, 3H, ArH), 4.00 (d, 2H, OCH2), 2.86 (m, 1H, CH), 2.14
(m, 2H, alkyls), 1.95 (m, 4H, alkyls), 1.65 (m, 2H, CH2), 0.95
(t, 3H, CH3). MS (ES+): m/z 290.0 (M + H). Anal. (C17H20-
FNO2) C, H, N, F.
6-Chloro-4-(cyclobutylmethoxy)-3-propyl-2(1H)-quino-
linethione (1f). The title compound was prepared from 4a
and cyclobutylmethyl bromide by the method outlined in the
synthesis of 1y. An 8% yield of 1f was obtained after chroma-
tography on silica gel (4 by 7 cm column) eluted with CHCl3/
MeOH (97:3, v/v, 2 times). 1H NMR (Me2SO-d6) δ 13.6 (bs, 1H,
NH), 7.67 (s, 1H, ArH), 7.62 (s, 2H, ArH), 4.00 (d, 2H, OCH2),
2.83 (t, 3H, alkyls), 2.1 (m, 2H, alkyls), 1.9 (m, 4H, alkyl), 1.55
(m, 2H, alkyls), 0.90 (t, 3H, CH3). MS (ES+): m/z 322.0 (M +
1). Anal. (C17H20ClNO2) C, H, N, Cl.
6-Fluoro-4-hydroxyl-3-isopropyl-2(1H)-quinolinone (4e).
The title compound was prepared from 2b (10 g, 80 mmol) and
3d by the method used in the synthesis of 4a except that the
reaction was run for 5 d. A 40% yield of 4e was obtained.
1H NMR (Me2SO-d6) δ 10.9 (bs, 1H, OH), 10.1 (bs, 1H, NH),

5932 Journal of Medicinal Chemistry, 2004, Vol. 47, No. 24
Freeman et al.
7.7 (d, 1H, ArH), 7.4-7.20 (m, 2H, ArH), 3.3 (m, overlap-
ping with DOH), 1.29 (d, 6H, CH3). MS (ES+): m/z 222.0 (M
+ H).
4-(Cyclobutylmethoxy)-6-fluoro-3-isopropyl-2(1H)-quin-
olinone (1g). The title compound was prepared from 4e by
the method used in the synthesis of 1y. A 2% yield of 1g was
obtained. 1H NMR (Me2SO-d6) δ 11.7 (bs, 1H, NH), 7.4-7.3
(m, 3H, ArH), 3.94 (d, 2H, OCH2), 2.9 (m, 1H, CH), 2.1 (m,
2H, alkyls), 1.93 (m, 4H, alkyls), 1.93 (d, 6H, CH3). MS (EI+):
m/z 305.0 (M+). Anal. (C17H20FNO2) C, H, N, F.
6-Fluoro-4-(cyclobutylmethoxy)-3-ethoxy-2(1H)-quino-
linone (1j). The title compound was prepared from 4r and
cyclobutylmethyl bromide by the method used for the synthesis
of 1y except a 60 °C oil bath was used. The reaction time was
48 h. 1j (8% yield) was isolated by chromatography on silica
gel (4 × 7 cm column) eluted with ethyl acetate/hexane (1:1).
1H NMR (CDCl3) δ 11.1 (bs,1H, NH), 7.52 (d, 1H, ArH), 7.24
(m, 1H, ArH), 7.15 (m, 1H, ArH), 4.42 (d, 2H, OCH2), 4.2 (q,
2H, OCH2), 2.81 (m, 1H, CH), 2.2-1.2 (m, alkyls), 0.87 (m,
2H). MS (ES+): m/z 292.0 (M + 1).
6-Chloro-4-hydroxy-3-isopropyl-2(1H)-quinolinone (4f).
The title compound was prepared from 2a and 3d by the
method used in the synthesis of 4a. 1H NMR (Me2SO-d6) δ
11.3 (bs, 1H, OH), 10.0 (bs, 1H, NH), 7.87 (s, 1H, ArH), 7.44
(d, 1H, ArH), 7.22 (d, 1H, ArH), 2.5 (m, overlapping with
DMSO), 1.22 (m, 6H, CH3). MS (ES+): m/z 238.0 (M + H).
6-Chloro-4-cyclobutylmethoxy-3-isopropyl-2(1H)-quin-
olinone (1h). The title compound was prepared from 4f and
cyclobutylmethyl bromide using the method employed for the
synthesis of 1y. A 22% yield of 1h was obtained. 1H NMR
(CDCl3) δ 12.5 (bs, 1H, NH), 7.70 (s, 1H, ArH), 7.40 (d, 1H,
ArH), 7.30 (d, 1H, ArH), 3.94 (d, 2H, OCH2), 3.45 (m, 1H, CH),
2.91 (m, 1H, CH), 2.22 (m, 2H, alkyls), 1.99 (m, 4H, alkyls),
1.45 (d, 6H, CH3). MS (EI+): m/z 305.0 (M+). Anal. (C17H20-
ClNO2) C, H, N, Cl.
4-Hydroxy-7-methoxy-3-propyl-2(1H)-quinolinone (4g).
The title compound was prepared from 2d and 3a by the
method used in the synthesis of 4a. 1H NMR (Me2SO-d6) δ
11.1 (bs, 1H, OH), 9.9 (bs, 1H, NH), 7.8 (d, 1H, ArH), 6.7-6.8
(m, 2H, ArH), 3.8 (s, 3H, MeO), 2.5 (m, overlapping with
DMSO, 2H, CH2), 1.3-1.5 (m, 2H, CH2), 0.9 (t, 3H, CH3).
7-Methoxy-4-(cyclobutylmethoxy)-3-propyl-2(1H)-quin-
olinone (1l). The title compound was prepared from 4g and
cyclobutylmethyl bromide by the method used for the synthesis
of 1y except a 60 °C oil bath was used. The reaction time was
48 h. 1l (22% yield) was isolated by chromatography on silica
gel (4 × 7 cm column) eluted with MeOH/CH2Cl2 (3:97). 1H
NMR (Me2SO-d6) δ 11.5 (bs,1H, NH), 7.5 (d, 1H, ArH), 6.7-
6.8 (m, 2H, ArH), 3.9 (d, 2H, OCH2), 3.8 (s, 3H, OCH3), 2.7-
2.8 (m, 1H, CH), 2.3-2.4 (m,), 2-2.1 (m, 2H, CH2), 1.9-2 (m,
6H, cyclobut), 1.4-1.5 (m, 2H, CH2), 0.9 (t, 3H, CH3).
6-Fluoro 4-hydroxy-5-nitro-3-propyl-2(1H)-quinoli-
none (4h). A mixture of 2e (1.5 g, 4.8 mmol), 3a and Na2CO3
(1.0 g, 9.6 mmol) in H2O (20 mL) was heated to reflux for 1 h.
The reaction mixture was cooled to room temperature and
acidified with 2 N HCl. A precipitate formed and was collected
by filtration and washed repeatedly with water. After drying,
1.24 g of a yellow solid was obtained. The solid was mixed with
polyphosphoric acid (20 mL) and was heated to 120 °C for 4
h. The reaction mixture was cooled to room temperature, 2 N
HCl was added (20 mL). A precipitate formed and was collected
and dried. 4h (0.94 g, 74% yield) was obtained as a light yellow
solid. 1H NMR (Me2SO-d6) δ 11.8 (s, 1H), 11.0 (br s, 1H), 7.72
(t, 1H), 7.48 (dd, 1H), 2.5 (m, overlapping with DMSO), 1.4-
1.5 (m, 2H), 0.92 (t, 3H).
4-(Cyclobutylmethoxy)-6-fluoro-5-nitro-3-propyl-2(1H)-
quinolinone (1m). To a stirred suspension of NaH (0.25 g of
a 50% dispersion in oil, 5.3 mmol) in DMF (10 mL) was added
portionwise 0.94 g of 4h. After stirring for 10 min, cyclobu-
tylmethyl bromide (0.47 mL, 4.2 mmol) was added. The
reaction mixture was stirred for 24 h. The mixture was then
concentrated and dry-packed on silica gel. Flash column
chromatography on silica with 5% MeOH in CH2Cl2 gave 1m
(0.16 g, 14% yield) as a peach-colored solid. 1H NMR (Me2SO-
d6) δ 12.23 (br s, 1H), 7.75 (t, 1H), 7.54 (dd, 1H), 3.8 (d, 2H),
2.6-2.8 (m, 1H), 2.5 (m, overlapping with DMSO), 1.8-2.2 (m,
6H), 1.5-1.7 (m, 2H), 0.95 (t, 3H).
Methyl 5-chloro-2-[(2-ethoxyacetyl)amino]benzoate
(6a). Methyl 2-amino-5-chlorobenzoate, 5a (1.0 g, 5.4 mmol,
Sigma-Aldrich), was dissolved in CH2Cl2 (10 mL). Ethoxyacetyl
chloride (1.0 g, 8.1 mmol) (see footnote for preparation) was
added followed by Et3N (2.2 mL, 16 mmol). The reaction was
stirred at room temperature for 5 min. Water was added, and
the mixture was transferred to a separatory funnel. The
organic layer was washed with saturated ammonium chloride
(2×). The solvent was removed in vacuo, and the product was
isolated by chromatography on silica gel (4 × 15 cm column)
eluted with chloroform/methanol (98:2, v/v-500 mL followed
1
by 95:5, 300 mL) to give a 55% yield of 6a. H NMR (CDCl3)
δ 11.1 (bs, 1H, NH), 8.78 (d, 1H, ArH), 8.01 (s, 1H, ArH), 7.49
(d, 1H, ArH), 4.1 (s, 2H,CH2), 3.95 (s, 3H, OCH3), 3.65 (m, 2H,
CH2), 1.38 (m, 3H, CH3). MS (ES+): m/z 272.0 (M + 1).
6-Chloro-3-ethoxy-4-hydroxy-2(1H)-quinolinone (4q).
6a (0.20 g, 0.74 mmol) was boiled in toluene to remove excess
H2O. The excess toluene was removed in vacuo. The concen-
trate was dissolved in THF (8 mL) and chilled to -78 °C.
Potassium bis(trimethylsilyl)amide (4.4 mL of a 0.5 M solution
in toluene, 2.2 mmol) was added over 5 min. The reaction was
stirred for 5 min and transferred to a 0 °C bath. The reaction
was stirred for 30 min and then allowed to warm to room
temperature and stir overnight. The reaction was poured onto
ice-water (15 mL) and extracted with ethyl acetate (20 mL).
The solvent was removed in vacuo, and 4q (22% yield) was
isolated by filtration through silica gel (10 g) eluted with ethyl
acetate/hexane (1:4, v/v). 1H NMR (CDCl3) δ 11.6 (bs, 1H, NH),
10.6 (bs, 1H, OH), 7.68 (s, 1H, ArH), 7.42 (d, 1H, ArH), 7.22
(d, 1H, ArH), 4.04 (q, 2H, OCH2), 1.22 (t, 2H, CH3). MS
(ES+): m/z 240.0 (M + 1).
4-Hydroxy-3-propyl-2(1H)-quinolinone (4i). The title
compound was prepared from 2f and 3a by the method
1
outlined for the synthesis of 4a in 73% yield. H NMR (Me2-
SO-d6) δ 11.2 (bs, 1H, OH), 9.94 (bs, 1H, NH), 7.82 (d, 1H,
ArH), 7.39 (t, 1H, ArH), 7.19 (d, 1H, ArH), 7.09 (t, 1H, ArH),
2.5 (m, overlapping with DMSO), 1.40 (m, 2H, CH2), 0.86 (t,
3H, CH3). MS (ES+): m/z 204.0 (M + 1).
6-Chloro-4-(cyclobutylmethoxy)-3-ethoxy-2(1H)-quino-
linone (1i). The title compound was prepared from 4q and
cyclobutylmethyl bromide by the method used for the synthesis
of 1y except a 60 °C oil bath was used. The reaction time was
48 h. 1i (11% yield) was isolated by chromatography on silica
gel (4 × 7 cm column) eluted with ethyl acetate/hexane (1:1).
1H NMR (CDCl3) δ 10.4 (bs, 1H, NH), 7.8(s, 1H, ArH), 7.36 (d,
1H, ArH), 7.14 (d, 1H, ArH), 4.42 (d, 2H, OCH2), 4.2 (q, 2H,
OCH2), 2.81 (m, 1H, CH), 2.2-1.2 (m, alkyls), 0.87 (m, 2H).
MS (ES+): m/z 308.0 (M + 1).
Methyl 5-fluoro-2-[(2-ethoxyacetyl)amino]benzoate (6b).
The title compound was prepared from 5b (made from the acid,
Sigma-Aldrich, by esterification in ethanol/toluene with one
drop of concd H2SO4) by the method used for 6a and was used
without chromatography in the synthesis of 1j. 1H NMR
(CDCl3) δ 11.7 (bs, 1H, NH), 8.78 (dd, 1H, ArH), 7.72 (dd, 1H,
ArH), 7.24 (m, 1H, ArH), 4.4 (m, 2H,OCH2), 4.1 (m, 2H, OCH2),
3.7 (s, 2H, OCH2), 1.2 (m, 6H, CH3).
4-Cyclopentyloxy-3-propyl-2(1H)-quinolinone (1n). The
title compound was prepared from 4i using the method
employed for the synthesis of 1y. A 9% yield of 1n was
obtained. 1H NMR (Me2SO-d6) δ 11.6 (bs, 1H, NH), 7.64 (d,
1H, ArH), 7.42 (t, 1H, ArH), 7.25 (d, 1H, ArH), 7.15 (t, 1H,
ArH), 4.70 (s, 1H, OCH), 2.5 (m, overlapping with DMSO), 1.80
(m, 6H, alkyls), 1.60 (m, 2H, CH2), 1.50 (m, 2H, CH2), 0.88 (t,
3H, CH3). MS (ES+): m/z 272.0 (M + 1). Anal. (C17H21NO2)
C, H, N.
6-Bromo-4-hydroxy-3-propyl-2(1H)-quinolinone (4j).
The title compound was prepared from 2c and 3a by the
method outlined for the synthesis of 4a in 58% yield. 1H NMR
(Me2SO-d6) δ 11.4 (bs, 1H, OH), 10.2 (bs, 1H, NH), 7.95 (s,
1H, ArH), 7.54 (d, 1H, ArH), 7.15 (d, 1H, ArH), 2.5 (m,

Inhibitors of HIV-1 Reverse Transcriptase
Journal of Medicinal Chemistry, 2004, Vol. 47, No. 24 5933
overlapping with DMSO), 1.40 (m, 2H, CH2), 0.86 (t, 3H, CH3).
MS (ES+): m/z 284.0 (M + 1).
(m, 8H, CH2), 1.60 (m, 2H, CH2), 1.25 (d, 3H, CH3), 0.73 (t,
3H, CH3). MS (ES+): m/z 320.0 (M + 1).
6-Bromo-4-(cyclopentyloxy)-3-propyl-2(1H)-quinoli-
none (1o). The title compound was prepared from 4j using
the method employed in the synthesis of 1y. A 7% yield of 1o
4-Hydroxy-6-methyl-3-propyl-2(1H)-quinolinone (4n).
The title compound was prepared from 2g and 3a by the
method outlined for the synthesis of 4a in 75% yield. 1H NMR
(Me2SO-d6) δ 11.3 (bs, 1H, OH), 9.8 (bs, 1H, NH), 7.62 (s, 1H,
ArH), 7.21 (d, 1H, ArH), 7.09 (d, 1H, ArH), 2.5 (m, overlapping
with DMSO), 2.31 (s, 3H, CH3), 1.40 (m, 2H, CH2), 0.86 (t, 3H,
CH3). MS (ES+): m/z 218.0 (M + 1).
4-Cyclopentyloxy-6-methyl-3-propyl-2(1H)-quinoli-
none (1u). The title compound was prepared from 4n using
the method employed for the synthesis of 1y except the
reaction was heated for 2 h and a second portion of NaH (0.025
g, 0.50 eq) was added. The reaction was heated overnight. NaH
(0.025 g, 0.50 equiv) was added again and heating at 60 °C
was continued another 4 h. Purification was accomplished by
chromatography on silica gel eluted with CHCl3/MeOH (98:2,
v/v) resulting in 1u (2% yield). 1H NMR (Me2SO-d6) δ 11.5 (bs,
1H, NH), 7.41 (s, 1H, ArH), 7.24 (d, 1H, ArH), 7.15 (d, 1H,
ArH), 4.70 (m, 1H, OCH), 2.5 (m, overlapping with DMSO),
2.32 (s, 3H, CH3), 1.9-1.2 (m, 12H, CH2s), 0.88 (t, 3H, CH3).
MS (ES+): m/z 286.0 (M + 1).
4-Hydroxy-6-methoxy-3-propyl-2(1H)-quinolinone (4o).
The title compound was prepared from 2h and 3a by the
method outlined for the synthesis of 4a in 72% yield. 1H NMR
(Me2SO-d6) δ 11.2 (bs, 1H, OH), 9.9 (bs, 1H, NH), 7.38(s, 1H,
ArH), 7.19 (d, 1H, ArH), 7.1 (d, 1H, ArH), 3,80 (s, 3H, OCH3),
2.5 (m, overlapping with DMSO), 1.40 (m, 2H, CH2), 0.92 (t,
3H, CH3). MS (ES+): m/z 234.0 (M + 1).
4-Cyclopentyloxy-6-methoxy-3-propyl-2(1H)-quinoli-
none (1v). The title compound was prepared from 4o using
the method employed for the synthesis of 1y except the
reaction was heated in a 100 °C oil bath for 24 h. A 16% yield
of 1v was obtained. 1H NMR (Me2SO-d6) δ 11.5 (bs, 1H, NH),
7.20 (s, 1H, ArH), 7.10 (d, 1H, ArH), 7.06 (d, 1H, ArH), 4.70
(m, 1H, OCH), 3.75 (s, 3H, OCH3), 2.5 (m, overlapping with
DMSO), 1.80 (m, 6H, CH2s), 1.60 (m, 2H, CH2s), 1.50 (m, 2H,
CH2), 0.88 (t, 3H, CH3). MS (ES+): m/z 302.0 (M + 1).). Anal.
(C18H23NO3) C, H, N.
4-Hydroxy-3-propyl-6-trifluoromethoxy-2(1H)-quino-
linone (4p). The title compound was prepared from 2i and
3a by the method outlined for the synthesis of 4a in 40% yield.
1H NMR (Me2SO-d6) δ 11.5 (bs, 1H, OH), 10.3 (bs, 1H, NH),
7.8 (s, 1H, ArH), 7.5 (d, 1H, ArH), 7.3 (d, 1H, ArH), 2.5 (m,
overlapping with DMSO), 1.40 (m, 2H, CH2), 0.92 (t, 3H, CH3).
MS (ES+): m/z 288.0 (M + 1).
4-(Cyclopentyloxy)-3-propyl-6-trifluoromethoxy-2(1H)-
quinolinone (1w). The title compound was prepared from 4p
using the method employed in the synthesis of 1y. 1w was
obtained in 9% yield. 1H NMR (Me2SO-d6) δ 11.8 (bs, 1H, NH),
7.50 (s, 1H, ArH), 7.46 (d, 1H, ArH), 7.34 (d, 1H, ArH), 4.68
(m, 1H, OCH), 2.5 (m, overlapping with DMSO), 1.80 (m, 6H,
CH2s), 1.60 (m, 2H, CH2s), 1.50 (m, 2H, CH2), 0.88 (t, 3H, CH3).
MS (ES+): m/z 356.0 (M + 1). Anal. (C18H20F3NO3‚0.05CHCl3)
C, H, N, F.
4-Hydroxy-2-oxo-3-propyl-1,2-dihydro-6-quinolinecar-
bonitrile (4q). The title compound was prepared from 2j and
3a by the method outlined for the synthesis of 4a in 77% yield.
1H NMR (Me2SO-d6) δ 11.7 (bs, 1H, OH), 10.5 (bs, 1H, NH),
8.23 (s, 1H, ArH), 7.77 (d, 1H, ArH), 7.33 (d, 1H, ArH), 2.5
(m, overlapping with DMSO), 1.4 (m, 2H, CH2), 0.87 (t, 3H,
CH3). MS (ES+): m/z 229.0 (M + 1).
1
was obtained. H NMR (Me2SO-d6) δ 11.8 (bs, 1H, NH), 7.70
(s, 1H, ArH), 7.60 (d, 1H, ArH), 7.21 (d, 1H, ArH), 4.69 (m,
1H, OCH), 2.5 (m, overlapping with DMSO), 1.80 (m, 6H,
alkyls), 1.60 (m, 2H, CH2), 1.50 (m, 2H, CH2), 0.88 (t, 3H, CH3).
MS (ES+): m/z 352.0 (M + 1). Anal. (C17H20BrNO2‚0.25C6H14)
C, H, N.
4-Cyclopentyloxy-6-fluoro-3-propyl-2(1H)-quinoli-
none (1p). The title compound was prepared from 4d and
cyclopentyl bromide by the method used in the synthesis of
1y except the oil bath temperature was 50 °C. A 22% yield of
1p was obtained. 1H NMR (Me2SO-d6) δ 11.7 (bs, 1H, NH),
7.32 (m, 3H, ArH), 4.70 (m, 1H, OCH), 2.5 (m, overlapping
with DMSO), 1.80 (m, 6H, alkyls), 1.60 (m, 2H, CH2s), 1.50
(m, 2H, CH2), 0.88 (t, 3H, CH3). MS (ES+): m/z 290.0 (M +
1).
6-Chloro-4-(cyclopentyloxy)-3-propyl-2(1H)-quinoli-
none (1q). Starting from 4a and using the procedure described
for the synthesis of 1y, compound 1q (20% yield) was obtained
after chromatography on silica gel (4 by 7 cm column) eluted
with hexane/EtOAc (2:1, v/v). 1H NMR (Me2SO-d6) δ 11.8 (bs,
1H, NH), 7.56 (s, 1H, ArH), 7.49 (d, 1H, ArH), 7.28 (d, 1H,
ArH), 4.70 (m, 1H, OCH), 2.5 (m, overlapping with DMSO),
1.80 (m, 6H, alkyls), 1.60 (m, 2H, CH2s), 1.50 (m, 2H, CH2),
0.88 (t, 3H, CH3). MS (ES+): m/z 306.0 (M + 1). Anal. (C17H20-
ClNO2) C, H, N, Cl.
6-Chloro-3-ethyl-4-hydroxyl-2(1H)-quinolinone (4k). The
title compound was prepared from 2a and 3c by the method
1
outlined for the synthesis of 4a in 69% yield. H NMR (Me2-
SO-d6) δ 11.4 (bs, 1H, OH), 10.2 (bs, 1H, NH), 7.82 (s, 1H,
ArH), 7.44 (d, 1H, ArH), 7.21 (d, 1H, ArH), 2.5 (m, overlapping
with DMSO), 0.97 (t, 3H, CH3). MS (ES+): m/z 224.0 (M +
1).
6-Chloro-4-(cyclopentyloxy)-3-ethyl-2(1H)-quinoli-
none (1r). The title compound was prepared from 4k and
cyclopentyl bromide using the method employed for the
synthesis of 1y. A 12% yield of 1r was obtained. 1H NMR (Me2-
SO-d6) δ 11.8 (bs, 1H, NH), 7.62 (s, 1H, ArH), 7.5 (d, 1H, ArH),
7.33 (d, 1H, ArH), 4.8 (m, 1H, OCH), 2.5 (m, overlapping with
DMSO), 1.9 (m, 6H, alkyls), 1.60 (m, 2H, CH2s), 1.12 (t, 3H,
CH3). MS (ES+): m/z 292.0 (M + 1).
6-Chloro-4-hydroxyl-3-isobutyl-2(1H)-quinolinone (4l).
The title compound was prepared from 2a and 3e by the
method outlined for the synthesis of 4a except the reaction
was run for 72 h. A 51% yield of 4l was obtained. 1H NMR
(Me2SO-d6) δ 11.4 (bs, 1H, OH), 10.1 (bs, 1H, NH), 7.83 (s,
1H, ArH), 7.44 (d, 1H, ArH), 7.22 (d, 1H, ArH), 2.5 (m,
overlapping with DMSO), 1.86 (m, 1H, CH), 0.82 (m, 6H, CH3).
MS (ES+): m/z 252.0 (M + H).
6-Chloro-4-(cyclopentyloxy)-3-isobutyl-2(1H)-quinoli-
none (1s). The title compound was prepared from 4l using
the method employed for the synthesis of 1y. A 13% yield of
1
1s was obtained. H NMR (CDCl3) δ 10.4 (bs, 1H, NH), 7.70
(s, 1H, ArH), 7.35 (d, 1H, ArH), 7.15 (d, 1H, ArH), 4.73 (m,
1H, OCH), 2.60 (d, 2H, CH2), 2.08-1.54 (m, 9H, alkyls), 0.90
(t, 6H, CH3). MS (ES+): m/z 320.0 (M + 1). Anal. (C18H22-
ClNO2‚0.05CHCl3) C, H, N.
3-(sec-Butyl)-6-chloro-4-hydroxyl-2(1H)-quinolinone
(4m). The title compound was prepared from 2a and 3f by
4-Cyclopentyloxy-2-oxo-3-propyl-1,2-dihydro-6-quino-
linecarbonitrile (1x). The title compound was prepared from
4q using the method employed in the synthesis of 1y. A 15%
1
the method outlined for the synthesis of 4a in 35% yield. H
NMR (Me2SO-d6) δ 11.3 (bs, 1H, OH), 10.0 (bs, 1H, NH), 7.87
(s, 1H, ArH), 7.44 (d, 1H, ArH), 7.22 (d, 1H, ArH), 3.12 (m,
1H, CH), 1.87 (m, 1H, CH), 1.6 (m, 1H, CH), 1.2 (d, 3H, CH3),
0.7 (m, 3H, CH3). MS (ES+): m/z 252.0 (M + H).
1
yield of 1x was obtained. H NMR (Me2SO-d6) δ 12.0 (bs,1H,
NH), 8.00 (s, 1H, ArH), 7.82 (d, 1H, ArH), 7.37 (d, 1H, ArH),
4.74 (m, 1H, OCH), 2.5 (m, overlapping with DMSO), 1.80 (m,
6H, CH2s), 1.60 (m, 2H, CH2s), 1.50 (m, 2H, CH2), 0.88 (t, 3H,
CH3). MS (APCH-): m/z 295.0 (M-1). Anal. (C18H20N2O2) C,
H, N.
3-(sec-Butyl)-6-chloro-4-(cyclopentyloxy)-2(1H)-quino-
linone (1t). The title compound was prepared from 4m and
cyclopentyl bromide using the method employed for the
synthesis of 1y. A 2% yield of 1t was obtained. 1H NMR (Me2-
SO-d6) δ 11.6 (bs, 1H, NH), 7.56 (s, 1H, ArH), 7.49 (d, 1H, ArH),
7.28 (d, 1H, ArH), 4.60 (m, 1H, OCH), 3.0 (m, 1H, CH), 1.80
6-Chloro-4-(cyclohexyloxy)-3-isopropyl-2(1H)-quinoli-
none (1z). The title compound was prepared from 4f by the
method outlined for the synthesis of 1y. 1H NMR (Me2SO-d6)

5934 Journal of Medicinal Chemistry, 2004, Vol. 47, No. 24
Freeman et al.
δ 11.6 (bs, 1H, NH), 7.59 (s, 1H, ArH), 7.46 (d, 1H, ArH), 7.25
(d, 1H, ArH), 3.95 (m, 1H, CH), 1.95 (m, 1H, CH), 1.60 (d, 6H,
CH3), 1.28-1.20 (m, 10H, alkyls). MS (ES+): m/z 320.0 (M +
1).
NH), 7.90 (s, 1H, ArH), 7.69 (d, 1H, ArH), 7.45 (d, 1H, ArH),
2.81 (m, 2H, CH2), 1.67 (m, 2H, CH2), 1.2 (m, 1H, CH), 1.0 (m,
3H, CH3), 0.65 (m, 2H, CH2), 0.55 (m, 2H, CH2). MS (ES+):
m/z 302.0 (M + 1).
6-Chloro-4-(cyclohexylmethoxy)-3-propyl-2(1H)-quino-
linone (1aa). The title compound was prepared from 4a by
the same method used in the synthesis of 1y except the
reaction was heated in a 50 °C oil bath for 9 h followed by
heating in a 75 °C oil bath for 4 h. Following chromatography
on silica gel (4 by 7 cm column) eluted with CHCl3/MeOH (97:
6-Fluoro-3-isopropyl-4-(2,2,2-trifluoroethoxy)-2(1H)-
quinolinone (10c). The title compound was prepared from
4e using the method described for the synthesis of 10g. 1H
NMR (CDCl3) δ 12.6 (bs, 1H, NH), 7.42-7.35 (m, 2H, ArH),
7.28-7.23 (m, 1H, ArH), 4.31 (q, 2H, CH2), 3.4 (m, 1H, CH),
1.4 (d, 6H, CH3). MS (ES+): m/z 304.0 (M + 1).
1
3, v/v), 1aa (10% yield) was obtained. H NMR (Me2SO-d6) δ
2-[tert-Butyl(dimethyl)silyl]oxy-6-fluoro-3-isopropyl-
4-(2,2,2-trifluoroethoxy)quinoline (11c). 10c (0.92 g, 3.0
mmol) was dissolved in DMF (30 mL). tert-butyldimethylsilyl
chloride (0.95 g, 6.0 mmol) was added followed by Et3N (1.6
mL, 10.5 mmol). The reaction was stirred at room temperature
for 2.5 h. The mixture was poured into ice-water (250 mL).
The product was extracted with ether. The solution was dried
with MgSO4, filtered, and the solvent removed in vacuo to give
11.8 (bs, 1H, NH), 7.61 (s, 1H, ArH), 7.53 (d, 1H, ArH), 7.34
(d, 1H, ArH), 3.80 (m, 2H, OCH2), 2.5 (m, overlapping with
DMSO), 2.0-0.9 (m, 17H, alkyls). MS (ES+): m/z 334.0 (M +
1).
6-Chloro-3-propyl-4-(2,2,2-trifluoroethoxy)-2(1H)-quin-
olinone (10g). 4a (1.5 g, 6.3 mmol) was dissolved in DMF
(12 mL) and treated with NaH (0.55 g of a 60% oil dispersion,
13 mmol, 2.1 equiv) at room temperature for 5 min. 2-Bromo-
1,1,1-trifluoroethane (1.8 mL, 19.8 mmol) was added and the
reaction heated in a 150 °C oil bath for 48 h. The solution was
cooled to room temperature and poured onto ice-water (70
mL). The resulting precipitate was collected by filtration. The
product was isolated by filtration through silica gel (50 g)
eluted with EtOAc/hexane (3:7, v/v). The solvents were re-
moved in vacuo and the residue slurried in Et2O to give 10g
(0.5 g, 25%). 1H NMR (Me2SO-d6) δ 11.4 (bs, 1H, NH), 7.70 (s,
1H, ArH), 7.45 (d, 1H, ArH), 7.26 (d, 1H, ArH), 4.35 (q, 2H,
CH2), 2.66 (m, 2H, CH2), 1.66 (m, 2H, CH2), 1.01 (t, 3H, CH3).
MS (ES-): m/z 318.0 (M -1).
6-Chloro-2-[(4-methoxybenzyl)oxy]-3-propyl-4-quino-
linyl 2,2,2-trifluoroethyl Ether (13). 10g (0.26 g, 0.80 mmol)
was dissolved in DMF (3 mL). Silver(I) oxide (0.20 g, 0.86
mmol) was added followed by 4-methoxybenzyl chloride (0.135
mL,1.0 mmol) The reaction was heated in a 100 °C oil bath
overnight. The oil bath temperature was raised to 145 °C for
1 h. Silver(I) oxide (0.1 g, 0.4 mmol) and 4-methoxybenzyl
chloride (0.050 mL, 0.37 mmol) were added, the oil bath
temperature was adjusted to 110 °C and the reaction was
heated for 4 h. Silver(I) oxide (0.1 g, 0.4 mmol) and 4-meth-
oxybenzyl chloride (0.050 mL, 0.37 mmol) were again added
and the reaction was heated in the 145 °C oil bath for an
additional 1.5 h. The reaction was cooled to room temperature
and filtered. The filtrate was poured into water (25 mL), and
the resulting precipitate was collected by filtration. Following
filtration through silica gel (40 g) eluted with neat CHCl3, 13
was obtained as white solid in 47% yield. GCMS (EI): m/z 439
(M+), one peak.
6-Chloro-4-[(2-cyclopropylethynyl)oxy]-2-[(4-methoxy-
benzyl)oxy]-3-propylquinoline (14). 13 (0.14 g, 0.33 mmol)
was dissolved in ether (5 mL) and chilled to -78 °C. A solution
of cyclopropyllithium was prepared by the reaction of cyclo-
propyl bromide (0.93 mL, 12 mmol) with lithium wire (0.16 g,
23 mmol) in ether (10 mL) in a 0 °C bath for 1.5 h. Cyclopro-
pyllithium solution (4.0 mL, 2.3 mmol) was added at -78 °C,
and the reaction was allowed to warm to room temperature
overnight. The reaction was washed with sat. NH4Cl. The
organic phase was dried with MgSO4 and filtered and the
solvent removed in vacuo. Following purification by chroma-
tography on silica gel (4 × 7 cm column) eluted with CHCl3/
c-hexane (1:4, v/v), 14 was obtained in 32% yield. 1H NMR
(CDCl3) δ 8.06 (s, 1H, ArH), 7.78 (d, 1H, ArH), 7.55 (d, 1H,
ArH), 7.43 (d, 2H, ArH), 6.91 (d, 2H, ArH), 5.47 (s, 2H, CH2),
3.82 (s, 3H, OCH3), 2.84 (m, 2H, CH2), 1.60 (m, 2H, CH2), 1.15
(m, 1H, CH), 0.97 (t, 3H, CH3), 0.65 (m, 2H, CH2), 0.55 (m,
2H, CH2). GCMS (CI+): m/z 439.0 (M + NH4).
1
11c (1 g, 80%). H NMR (CDCl3) δ 7.70 (dd, 1H, ArH), 7.48
(dd, 1H, ArH), 7.32 (dd, 1H, ArH), 4.33 (q, 2H, CH2), 3.55 (m,
1H, CH), 1.4 (d, 6H, CH3), 1.06 (s, 9H, Si-t-Bu), 0.43 (s, 6H,
Si-CH3). MS (CI+): m/z 418.0 (M + 1).
4-[(2-Cyclopropylethynyl)oxy]-6-fluoro-3-(isopropyl)-
2(1H)-quinolinone (1ee). 11c (0.30 g, 0.75 mmol) was
dissolved in EtOAc/CH3CN (10 mL, 1:1, v/v). tert-butylammo-
nium fluoride hydrate (0.20 g, 1.1 mmol) was added. The
reaction was stirred at room temperature for 5 min. Sat. NaCl
solution was added and the product extracted with EtOAc. The
product was isolated by chromatography on silica gel (4 × 7
cm column) eluted with EtOAc/hexane (1:2, v/v). Final puri-
fication was accomplished by chromatography on C18 (Water’s
Symmetry C18 column, 19 × 150 mm) eluted with MeOH/
water (3:2, v/v) to give 1ee (0.043 g, 20%). 1H NMR (CDCl3) δ
11.6 (bs, 1H, NH), 7.61 (d, 1H, ArH), 7.58-7.22 (m, 2H, ArH),
3.60 (m, 1H, CH), 1.4 (d, 6H, CH3), 1.15 (m, 1H, CH), 0.68 (m,
2H, CH2), 0.56 (m, 2H, CH2). MS (ES+): m/z 286.0 (M + 1).
Anal. (C17H16FNO2‚0.25 H2O) C, H, N, F.
4-[(2-Cyclopropylethynyl)oxy]-6-fluoro-3-propyl-2(1H)-
quinolinone (1cc). The title compound was prepared from
1
4d according to the method described for compound 1ee. H
NMR (CDCl3) δ 10.9 (bs, 1H, NH), 7.59 (d, 1H, ArH), 7.25 (m,
2H, ArH), 2,78 (m, 2H, CH2), 1.66 (m, 2H, CH2), 1.19 (m, 1H,
CH), 1.04 (t, 3H, CH3), 0.68 (m, 2H, CH2), 0.56 (m, 2H, CH2).
MS (ES+): m/z 286.0 (M + 1).). Anal. (C17H16FNO2) C, H, N.
4-[(2-Cyclopropylethynyl)oxy]-3-ethyl-6-fluoro-2(1H)-
quinolinone (1bb). In a round-bottom flask equipped with a
stir bar and nitrogen on demand, 12a (0.2 g, 0.5 mmol) was
dissolved in anhydrous Et2O (6 mL) and cooled to -78 °C by
means of a dry ice/acetone bath. Cyclopropyllithium (3.5 mL
of a 0.50M solution in Et2O, 1.76 mmol) was added dropwise,
and the mixture was allowed to stir at -78 °C for 1h and was
then allowed to warm to room temperature. When judged to
be complete, the reaction mixture was quenched with sat. NH4-
Cl, and the layers were separated. The organic layer was dried
over Na2SO4, filtered and concentrated under reduced pres-
sure. The remaining residue was dissolved in THF and acidic
resin (BioRad, AG 50W-X4, 200-400 mesh, hydrogen form)
was added to the mixture. When the deprotection was judged
to be complete, the reaction was filtered and concentrated in
vacuo. The crude material was purified by column chroma-
tography, eluding with 3:1 hexanes/EtOAc to afford 1bb (18
mg, 10%) as a white solid. 1H NMR (Me2SO-d6) δ 12.11 (s, 1H),
7.41 (m, 3H), 2.68 (q, 2H), 1.25 (m, 1H), 1.15 (t, 3H), 0.76 (m,
2H), 0.55 (m, 2H). MS (ES) 270 (M-H). Anal. (C16H14FNO2)
C, H, N.
6-Chloro-4-[(2-Cyclopropylethynyl)oxy]-3-isopropyl-
2(1H)-quinolinone (1ff). 10d (108 mg, 0.25 mmol), prepared
from 4f by the method used to make 10g, was treated as
previously described in examples 1bb to give the crude
product. Purification was accomplished by flash chromatog-
raphy on silica gel (20% EtOAc/hexanes) to give 1ff (10 mg,
6-Chloro-4-[(2-cyclopropylethynyl)oxy]-3-propyl-2(1H)-
quinolinone (1dd). 12 (0.04 g, 0.1 mmol) was dissolved in
CH3CN (20 mL). A 10-mL aqueous solution of ammonium
cerium(IV) nitrate (0.055 g, 0.10 mmol) was then added to the
mixture. An immediate precipitate formed. Acetonitrile (20
mL) was added, along with ammonium cerium(IV) nitrate
(0.005 g, 0.01 mmol). 1dd (0.006 g, 20%) precipitated out and
was collected by filtration. 1H NMR (CDCl3) δ 11.9 (bs, 1H,
1
9%) as a white solid. H NMR (CDCl3, 400 MHz) δ 12.47 (s,
1H), 7.92 (d, 1H), 7.47 (m, 1H), 7.33 (d, 1H), 3.64 (m, 1H), 1.45

Inhibitors of HIV-1 Reverse Transcriptase
Journal of Medicinal Chemistry, 2004, Vol. 47, No. 24 5935
Table 3. Statistics for Crystallographic Structure
Determination of the RT-GW490745X Complex
(d, 6H), 1.18 (m, 1H), 0.71 (m, 2H), 0.59 (m, 2H). MS (ES-)
300 (M - H)-.
6-Fluoro-4-hydroxy-3-isobutyl-2(1H)-quinolone (4r). The
title compound was prepared according to the method of Cai
et al. (Cai, S. X.; Zhou, Z.; Haung, J.; Whittemore, E. R.;
Egbuwoku, Z. O.; Lu, Y.; Hawkinson, J. E.; Woodward, R. M.;
Weber, E.; Keana, J. F. W. J. Med. Chem. 1996, 39, 3248-
3255): 2b (15.87 g, 143 mmol) and 3e (71.06 g, 329 mmol)
were heated to 180 °C. The EtOH produced was collected in a
Dean-Stark trap (∼ 5 mL). After 6 h, the solution was cooled
to room temperature and a precipitate formed. The mixture
was combined with MeOH (80 mL), water (400 mL), and Na2-
CO3 (52 g) and heated to reflux for 1 h. Incomplete hydrolysis
was observed. The mix was neutralized with 2 N HCl and
filtered. The resulting solid was treated with 2 N LiOH (200
mL) and THF (200 mL) with stirring for 48 h. The THF was
removed in vacuo, and a precipitate was observed. The solid
was filtered, the filtrate was acidified to pH 1 with concen-
trated HCl and the resulting solid filtered. The solid was
treated with polyphosphoric acid (300 mL) at 140 °C for 3 h
and then cooled to room temperature. Aqueous HCl (1 N, 400
mL) was added and stirred for 4 h. The pH was adjusted to 4
with 20% NaOH. The resulting solid was filtered and dried in
data collection site
detector
PF BL-6A
Fuji BAS III
1.000
wavelength (Å)
unit cell dimensions (a, b, c in Å)
resolution range (Å)
observations
138.2, 109.7, 72.8
30.0-2.85
112938
unique reflections
completeness (%)
average I/σ(I)
26233
99.1
6.4
a
Rmerge
0.163
Outer Resolution Shell
resolution range (Å)
unique reflections
completeness (%)
average I/σ(I)
2.95-2.85
2527
98.0
0.9
Refinement Statistics
Resolution range (Å)
30.0-2.85
24824/1260
0.220/0.285
0.213
7725/21
0.0077
1.42
No. of reflections(working/test)
R-factorb (Rwork/Rfree
R-factorb (all data)
)
no. atoms (protein/inhibitor)
rms bond length deviation (Å)
rms bond angle deviation (deg)
mean B-factor (Å2)c
1
vacuo overnight to give 4r (21 g, 62%). H NMR (Me2SO-d6,
400 MHz) δ 11.30 (s, 1H), 7.58 (q, 1H), 7.30 (m, 1H), 7.22 (m,
1H), 2.43 (d, 2H), 1.87 (m, 1H), 0.83 (d, 6H). MS (ES-) 234
(M-H)-.
66/71/46
3.8
rms backbone B-factor deviation (Å2)
a Rmerge ) ∑|I - I |/∑ I ; b R-factor ) ∑|Fo- Fc|/∑Fo; c Mean B
6-Fluoro-3-isobutyl-4-(2,2,2-trifluoroethyl)-2(1H)-qui-
nolone (10e). 6-Fluoro-4-hydroxy-3-isobutyl-2(1H)-quinolone
(4r) (5 g, 21 mmol) was alkylated according to the procedure
described for the synthesis of 10g to give 10e (634 mg, 9.5%)
factor for main-chain, side-chain and inhibitor.
Crystallization, Data Collection and Structure Deter-
mination. Crystals of the RT-GW490745 complex were
grown from solutions containing RT at 26 mg/mL with a 1:1.1
molar ratio of compound, 6% PEG 3400, buffered with citrate/
phosphate, pH 5.0, using the sitting-drop method as described
previously.23 The crystals were partially dehydrated by in-
creasing the PEG concentration to 50% over 3 days prior to
data collection. X-ray data were collected at the Photon
Factory, KEK, Japan, at 100 K using a Weissenberg camera.24
Data frames of 3.5° with a coupling constant 1.5°/mm were
collected with an exposure time of 210 s. Indexing and
integration of data images were carried out with DENZO, and
data were merged with SCALEPACK.25
The orientation and position of the RT molecule in the cell
were determined using rigid-body refinement with an initial
model of RT-MKC442 (PDB code 1rt1,).26 Rounds of positional,
simulated annealing and individual B-factor refinement with
bulk solvent correction and model rebuilding resulted in the
current structure with R-factor of 0.213 for all the data and
rms deviations of 0.008 Å and 1.4° from ideality for bond
lengths and bond angles, respectively. Both the bound inhibitor
as well as the protein residues around it, have well-defined
electron density (Figure 4a). Due to the limited reflections-to-
parameters ratio, atoms distal to the NNRTI site (defined as
>20 Å from the CR of Y188) were tightly restrained to their
positions after domain-wise rigid-body refinement. Refinement
and model rebuilding were carried out with programs CNS27
and O.28 Table 3 shows the X-ray data and crystallographic
refinement statistics.
1
as a white powder. H NMR (CDCl3) δ 7.30 (m, 3H), 4.36 (q,
2H), 2.61 (d, 2H), 2.13 (m, 1H), 0.97 (d, 6H). MS (ES+) 318
(M + H)+.
4-[(2-Cyclopropylethynyl)oxy]-6-fluoro-3-isobutyl-2(1H)-
quinolinone (1gg). Compound 10e was protected according
to the procedure described for 11a to give 11e as a partially
pure oil after flash chromatography (2% EtOAc/hexane, neu-
tral alumina). Without further purification, 10e was converted
to 1gg following the procedure described for the synthesis of
1ee. Flash chromatography (20% EtOAc/hexane, neutral
alumina), afforded compound 1gg (17 mg, 10%) as a white
solid. 1H NMR (CDCl3) δ12.45 (s, 1H), 7.65 (dd, 1H), 7.40 (dd,
1H), 7.29 (m, 1H), 2.76 (d, 2H), 2.13 (quint, 1H), 1.18 (m, 1H),
1.00 (d, 6H), 0.71 (m, 2H), 0.59 (m, 2H). MS (ES+) 300 (M +
H)+. (C18H18FNO2‚0.3H2O) C, H, N, F.
6-Fluoro-3-isopropyl-4-[(3-methylpent-1-ynyl)oxy]-
2(1H)-quinolinone (1hh). Starting with 4e and following the
procedure described for the synthesis of 1ee, compound 1hh
1
was obtained. H NMR (CDCl3) δ 12.1 (bs, 1H, NH), 7.68 (d,
1H, ArH), 7.38-7.26 (m, 2H, ArH), 3.68 (m, 1H, CH), 2.33 (m,
1H), 1.4 (m, 8H), 1.12 (m, 3H, CH3), 0.92 (m, 3H, CH3). MS
(ES+): m/z 302.0 (M + 1).
3-Cyano-4-hydroxy-2(1H)-quinolone (4s). Isatoic anhy-
dride (7) (1.63 g, 10 mmol), ethyl cyanoacetate (8) (1 mL, 10
mmol) and Et3N (3 mL, 20 mmol) were mixed and heated in
20 mL of DMF at 150 °C for 18 h. The reaction mixture was
concentrated in vacuo followed by the addition of 1 N HCl.
Precipitate was collected by filtration, washed with H2O and
1
dried. This resulted in 4s (1.52 g, 82%). H NMR (Me2SO-d6)
δ 11.7 (s, 1H, OH), 8 (d, 1H, ArH), 7.6 (t, 1H, ArH), 7.25 (d,
1H, ArH), 7.2 (t, 1H). MS (ES) 185 (M - H).
References
(1) Baltimore, D. RNA-dependent DNA polymerase in virions of
RNA tumor viruses. Nature 1970, 226, 1209-1211.
3-Cyano-4-(cyclobutylmethoxy)-2(1H)-quinolinone (1k).
The title compound was prepared from 4s by the method used
in the synthesis of 1y. 1k (5% yield) was isolated by chroma-
tography on silica gel eluted with MeOH/EtOAc (1:9). 1H NMR
(Me2SO-d6) δ 7.9 (d, 1H, ArH), 7.4 (t, 1H, ArH), 7.2 (d, 1H,
ArH), 6.95(t, 1H), 4.1 (d, 2H, CH2), 2.5-2.7 (m, 1H, CH), 1.6-
1.9 (m, 6H, cyclobutyl). MS (ES) 185 (M-H).
(2) Merluzzi, V. J.; Hargrave, K. D.; Labadia, M.; Grozinger, K.;
Skoog, M.; Wu, J. C.; Shih, C. K.; Eckner, K.; Hattox, S.; Adams,
J. Inhibition of HIV-1 replication by a nonnucleoside reverse
transcriptase inhibitor. Science 1990, 250 (4986), 1411-1413.
(3) Freimuth, W. W. Delavirdine mesylate, a potent nonnucleoside
HIV-1 reverse transcriptase inhibitor. Adv. Exp. Med. Biol. 1996,
394, 279-289.
(4) Young, S. D.; Britcher, S. F.; Tran, L. O.; Payne, L. S.; Lumma,
W. C.; Lyle, T. A.; Huff, J. R.; Anderson, P. S.; Olsen, D. B.;
Carroll, S. S.; Pettibone, D. J.; O’Brien, J. A.; Ball, R. G.; Balani,
S. K.; Lin, J. H.; Chen, I.-W.; Schleif, W. A.; Sardana, V. V.; Long,
W. J.; Byrnes, V. W.; Emini, E. A. L-743,726 (DMP-266): a Novel
Highly Potent Nonnucleoside Inhibitor of the Human Immuno-
Preparation of Ethoxyacetyl Chloride. Ethoxyacetic
acid was reacted neat with thionyl chloride, 1.7 equiv, at room
temperature for 1 h followed by heating in a 70 °C oil bath for
30 min. The product was purified by distillation at 120 °C at
room pressure from a 180 °C oil bath.

5936 Journal of Medicinal Chemistry, 2004, Vol. 47, No. 24
Freeman et al.
deficiency Virus Type 1 Reverse Transcriptase. Antimicrob.
Agents Chemother. 1995, 39, 2602-2605.
(21) Kellam, P.; Larder, B. A. Recombinant virus assay: a rapid,
phenotypic assay for assessment of drug susceptibility of human
immunodeficiency virus type 1 isolates. Antimicrob Agents
Chemother. 1994, Jan; 38 (1), 23-30.
(22) Gerondelis, P.; Archer, R. H.; Palaniappan, Chockalingam;
Reichman, Richard C.; Fay, Philip J.; Bambara, Robert A.;
Demeter, Lisa M. The P236L delavirdine-resistant human
immunodeficiency virus type 1 mutant is replication defective
and demonstrates alterations in both RNA 5′-end- and DNA 3′-
end-directed RNase H activities. J. Virol. 1999, 73 (7), 5803-
5813.
(23) Stammers, D. K.; Somers, D. O. N.; Ross, C. K.; Kirby, I.; Ray,
P. H.; Wilson, J. E.; Norman, M.; Ren, J. S.; Esnouf, R. M.;
Garman, E. F.; Jones, E. Y.; Stuart, D. I. Crystals of HIV-1
Reverse Transcriptase Diffracting to 2‚2 Å Resolution. J. Mol.
Biol. 1994, 242, 586-588.
(24) Sakabe, N. X-ray diffraction data collection system for modern
protein crystallography with a Weissenberg camera and an
imaging plate using synchrotron radiation. Nucl. Instr. Methods
Phys. Res. 1991, 303, 448-463.
(25) Otwinowski, Z.; Minor, W. Processing of X-ray diffraction data
collected in oscillation mode. Methods Enzymol. 1997, 276, 307-
326.
(26) Hopkins, A. L.; Ren, J.; Esnouf, R. M.; Willcox, B. E.; Jones, E.
Y.; Ross, C.; Miyasaka, T.; Walker, R. T.; Tanaka, H.; Stammers,
D. K.; Stuart, D. I. Complexes of HIV-1 Reverse Transcriptase
with Inhibitors of the HEPT Series Reveal Conformational
Changes Relevant to the Design of Potent Non-Nucleoside
Inhibitors. J. Med. Chem. 1996, 39, 1589-1600.
(27) Brunger, A. T.; Adams, P. D.; Clore, G. M.; Delano, W. L.; Gros,
P.; Grosse, K. R. W.; Jiang, J. S.; Kuszewski, J.; Nilges, M.;
Pannu, N. S.; Read, R. J.; Rice, L. M.; Simonson, T.; Warren, G.
L. Crystallography & NMR System: A New Software Suite for
Macromolecular Structure Determination. Acta Crystallogr.
1998, D54, 905-921.
(28) Jones, T. A.; Zou, J. Y.; Cowan, S. W.; Kjeldgaard, M. Improved
methods for building protein models in electron density maps
and the location of errors in these models. Acta Crystallogr. 1991,
A47, 110-119.
(5) Esnouf, R. M.; Ren, J.; Hopkins, A. L.; Ross, C. K.; Jones, E. Y.;
Stammers, D. K. Stuart, D. I. Unique features in the structure
of the complex between HIV-1 reverse transcriptase and the bis-
(heteroaryl)piperazine (BHAP) U-90152 explain resistance mu-
tations for this nonnucleoside inhibitor. Proc Natl. Acad. Sci.
U.S.A. 1997, 94, 3984-3989.
(6) Montaner, J. S. G.; Reiss, P.; Cooper, D.; Vella, S.; Harris, M.;
Conway, B.; Wainberg, M. A.; Smith, D.; Robinson, P.; Hall, D.;
Myers, M.; Lange, J. M. A. for the INCAS Study Group. A
Randomized, Double-blind Trial Comparing Combinations of
Nevirapine, Didanosine, and Zidovudine for HIV-Infected Pa-
tients The INCAS Trial. J. Am. Med. Assoc. 1998, 279, 930-
937.
(7) Bacheler, L. T.; Anton, E. D.; Kudish, P.; Baker, D.; Bunville,
J.; Krakowski, K.; Bolling, L.; Aujay, M.; Wang, X. V.; Ellis, D.;
Becker, M. F.; Lasut, A. L.; George, H. J.; Spalding, D. R.; Hollis,
G.; Abremski, K. Human immunodeficiency virus type 1 muta-
tions selected in patients failing efavirenz combination therapy.
Antimicrob. Agents Chemother. 2000, 44, 2475-2484.
(8) Adkins, J. C.; Noble, S. Efavirenz. Drugs 1998, 56, 1055-1066.
(9) Graul, A.; Rabasseda, J.; Castaner, J. Efavirenz. Drugs Future
1998, 23, 133-141.
(10) Schinazi, R. F.; Larder, B. A.; Mellors, J. W. Mutations in
retroviral genes associated with drug resistance: 2000-2001
update. Int. Antiviral News 2000, 8, 65-91.
(11) Hopkins, A. L.; Chan, J. H.; Freeman, G. A.; Andrews, C. W.,
III; Milton, J.; Stammers, D. K.; Stuart, D. I. Design of
nonnucleoside inhibitors of HIV-1 reverse transcriptase with
improved Drug Resistance Properties. Part I. J. Med. Chem.
(12) Rugheimer, L. Berichte 1884, 17, 734. (b) Osbourne, A. G.; Buley,
J. M.; Clarke, H.; Dakin, R. C. H.; Price, P. I. 2,4-dihalogeno-
quinolines. Synthesis, orientation effects and 1H and 13C NMR
spectral studies. J. Chem. Soc., Perkins Trans. 1 1993, 22, 2747-
2755.
(13) Andrews, C. W., III; Freeman, G. A.; Hopkins, A. L. Quinolone
compounds for use in treating viral infections, particularly AIDS.
PCT Int. Appl. WO 0146150 A2 20010628, 2001.
(14) Khalifa, M. A. E.; Zayed, E. M.; Mohamed, M. H.; Elnagdi, M.
H. Activated nitriles in heterocyclic synthesis: reaction of ethyl
cyanoacetate with anthranilic acid. Indian J. Chem., Sect. B:
Org. Chem. Incl. Med. Chem. 1983, 22B (6), 552-554.
(15) Longone, D. T.; Wright, W. D. Tetrahedron Letters 1969, 33,
2859-2862.
(16) Youngdale, G. A.; Oglia, T. F. J. Med. Chem. 1985, 28, 1790-
1796.
(17) Thompson, A. S.; Corley, E. G.; Grabowski, E. J. J.; Yasuda, N.
Asymmetric synthesis of (-)-6-chloro-4-cyclopropylethynyl-4-
trifluoromethyl-1,4-dihydro-2H-3,1-benzoxazin-2-one as HIV re-
verse transcription inhibitor. PCT Int. Appl. WO 9637457 A1
1996112, 1996.
(29) Esnouf, R. M.; Ren, J.; Hopkins, A. L.; Ross, C. K.; Jones, E. Y.;
Stammers, D. K.; Stuart, D. I. Unique features in the structure
of the complex between HIV-1 reverse transcriptase and the bis-
(heteroaryl)piperazine (BHAP) U-90152 explain resistance mu-
tations for this nonnucleoside inhibitor. Proc. Natl. Acad. Sci.
U.S.A. 1997, 94, 3984-3989.
(30) Ren, J.; Esnouf, R. M.; Hopkins, A. L.; Warren, J.; Balzarini, J.;
Stuart, D. I.; Stammers, D. K.Crystal Structures of HIV-1
Reverse Transcriptase in Complex with Carboxanilide Deriva-
tives. Biochemistry 1998, 37, 14394-14403.
(31) Ren, J.; Milton, J.; Weaver, K. L.; Short, S. A.; Stuart, D. I.;
Stammers, D. K. Structural basis for the resilience of efavirenz
(DMP-266) to drug resistance mutations in HIV-1 reverse
transcriptase. Structure Fold. Des. 2000, 8, 1089-1094.
(32) Ren, J.; Esnouf, R.; Hopkins, A.; Ross, C.; Jones, Y.; Stammers,
D.; Stuart, D. The structure of HIV-1 reverse transcriptase
complexed with 9-chloro-TIBO: lessons for inhibitor design.
Structure 1995, 3, 915-926.
(18) Hazen, R.; Lanier, E. Relative anti-HIV-1 efficacy of lamivudine
and emtricitabine in vitro is dependent on cell type. J. Acquired
Immune Defic. Syndr. 2003, 32, 255-258.
(19) Young, Steven D.; Britcher, Susan F.; Tran, Lee O.; Payne, Linda
S.; Lumma, William C.; Lyle, Terry A.; Huff, Joel R.; Anderson,
Paul S.; Olsen, David B.; et al. L-743, 726 (DMP-266): a novel,
highly potent nonnucleoside inhibitor of the human immuno-
deficiency virus type 1 reverse transcriptase. Antimicrob. Agents
Chemother. 1995, 39 (12), 2602-2605.
(20) Hansch, C.; Leo, A.; Hoekman, D. Exploring QSAR; American
Chemical Society: Washington, DC, 1995.
JM040072R