Novel nonnucleoside inhibitors of HIV-1 reverse transcriptase. 8. 8- Aryloxymethyl- and 8-arylthiomethyldipyridodiazepinones

Article abstract of DOI:10.1021/jm9707030

Nevirapine (I) is the first human immunodeficiency virus type 1 (HIV-1) nonnucleoside reverse transcriptase (RT) inhibitor to reach regulatory approval. As a result of a second generation program around the tricyclic core system of nevirapine, 2-chloro-5,11-dihydro-11-ethyl-5-methyl-8-(2- (pyridin-4-yl)ethyl)-6H-dipyrido[3,2-b:2',3'-e][1,4]diazepin-6-one (II)^1a and 2-chloro-5,11dihydro-11-ethyl-5-methyl-8-phenylethyl-6H-dipyrido[3-2- b:2',3'-e][1,4]diazepin-6-one (III)^1a were identified as broad spectrum HIV-1 RT inhibitors. A detailed examination of replacing either of the methylenes of the 8-ethyl linker of II or III is presented. It was found that 8-aryloxymethyl and 8-arylthiomethyl are the preferred pattern of substitution for potency against RT. The most potent compounds were further evaluated against a panel of clinically significant mutant RT enzymes (K103N, V106A, G190A, P236L) and in cytotoxicity and in vitro metabolism assays. The most potent compound was 2-chloro-8-phenylthiomethyl analogue 37 which displayed sub-100 nM activity against all HIV-1 RT enzymes tested.

Full text of DOI:10.1021/jm9707030

2972
J . Med. Chem. 1998, 41, 2972-2984
Novel Non n u cleosid e In h ibitor s of HIV-1 Rever se Tr a n scr ip ta se. 8.
8-Ar yloxym eth yl- a n d 8-Ar ylth iom eth yld ip yr id od ia zep in on es1
Charles L. Cywin,*,† J anice M. Klunder,†,2 MaryAnn Hoermann,† J anice R. Brickwood,‡ Eva David,‡,3
Peter M. Grob,‡ Racheline Schwartz,‡ Daniel Pauletti,‡ Kevin J . Barringer,‡ Cheng-Kon Shih,‡
Christopher L. Sorge,§ David A. Erickson,§ David P. J oseph,§ and Susan E. Hattox§
Research and Development Center, Boehringer Ingelheim Pharmaceuticals Inc., 900 Ridgebury Road, P.O. Box 368,
Ridgefield, Connecticut 06877
Received October 16, 1997
Nevirapine (I) is the first human immunodeficiency virus type 1 (HIV-1) nonnucleoside reverse
transcriptase (RT) inhibitor to reach regulatory approval. As a result of a second generation
program around the tricyclic core system of nevirapine, 2-chloro-5,11-dihydro-11-ethyl-5-methyl-
8-(2-(pyridin-4-yl)ethyl)-6H-dipyrido[3,2-b:2′,3′-e][1,4]diazepin-6-one (II)1a and 2-chloro-5,11-
dihydro-11-ethyl-5-methyl-8-phenylethyl-6H-dipyrido[3,2-b:2′,3′-e][1,4]diazepin-6-one (III)1a were
identified as broad spectrum HIV-1 RT inhibitors. A detailed examination of replacing either
of the methylenes of the 8-ethyl linker of II or III is presented. It was found that
8-aryloxymethyl and 8-arylthiomethyl are the preferred pattern of substitution for potency
against RT. The most potent compounds were further evaluated against a panel of clinically
significant mutant RT enzymes (K103N, V106A, G190A, P236L) and in cytotoxicity and in
vitro metabolism assays. The most potent compound was 2-chloro-8-phenylthiomethyl analogue
37 which displayed sub-100 nM activity against all HIV-1 RT enzymes tested.
In tr od u ction
changes and rendering the enzyme incompetent.9 In the
clinic, nevirapine monotherapy results in relatively
rapid drug resistance due to mutation of the RT enzyme.
Especially significant is the Y181C mutation which is
the primary strain of resistant HIV-1 RT found in
clinical isolates of patients on nevirapine monothera-
py.10 Here and in the preceding paper1a we present our
successful design of a second generation inhibitor which
retains nevirapine’s favorable properties of wild-type RT
potency, metabolic stability, good bioavailability and
relatively low toxicity while adding broad spectrum
activity against a variety of clinically relevant mutant
RT enzymes. We found empirically that activity against
wild-type (WT), Y181C, and Y188L enzymes provided
good indication of potential potency against a larger
number of mutants including those which have been
identified in the clinical isolates of patients undergoing
NNRTI monotherapy. As reported in the preceding
paper, 8-arylalkyl substituents improve potency against
several of these clinically significant mutants. The
combination of the 8-substituent with a 2-halo substitu-
ent such as chlorine or fluorine as exemplified in
compounds II and III was particularly effective. Modi-
fications of the 8-ethyl linker of either of these com-
pounds were not, however, fully explored and it was
shown that this linker was a major site of metabolism.1a
The major focuses of this report are the modifications
of this linker in order to improve potency and determin-
ing their effect on metabolic stability. We have found
that replacing one of the carbon atoms of the linker with
a heteroatom, such as N, O, or S, in combination with
changes in the aryl component has a significant impact
on the potency of inhibitors and metabolic stability. We
have identified several compounds with good activity
Nevirapine4 (Viramune, I) was the first nonnucleoside
reverse transcriptase inhibitor (NNRTI) to receive
regulatory approval for the treatment of HIV-1 infection
and is currently used in combination with nucleoside
RT inhibitors such as AZT, 3TC, D4T, and DDI.5 It has
also been shown to have synergistic effects with the
protease inhibitor saquinavir in vitro.6 Clinical trials
examining combinations of nevirapine and other HIV-
protease inhibitors also show great promise.7 Although
combination therapy has become the standard of care,
no single combination has proven completely effective
in all patients and there is a need to develop new
therapeutics with improved profiles.8
Nevirapine binds to an allosteric site on RT close to
the polymerase active site inducing conformational
† Department of Medicinal Chemistry.
‡ Department of Inflammatory Diseases.
§ Department of Drug Metabolism and Pharmacokinetics.
S0022-2623(97)00703-6 CCC: $15.00 © 1998 American Chemical Society
Published on Web 07/11/1998

Inhibitors of HIV-1 Reverse Transcriptase. 8
J ournal of Medicinal Chemistry, 1998, Vol. 41, No. 16 2973
Sch em e 1. Synthesis of 8-Bromo-2-halo-5,11-dihydro-11-ethyl-5-methyl-6H-dipyrido[3,2-b:2′,3′-e][1,4]diazepin-6-one
Starting Materialsa
a
(a) Pyridine, 1,4-dioxane, cyclohexane, 80%; (b) EtNH2, xylenes, 165 °C, 60%; (c) Br2, AcOK, AcOH, 88%; (d) NaHMDS, pyridine, 50
°C, 92%; (e) NaH, MeI, DMF, 50 °C, 88%; (f) p-methoxybenzylamine, 1,4-dioxane, 170 °C, 4 days, 47%; (g) TFA, 58%; (h) HF‚pyridine,
NaNO2, 87%.
against a panel of competent mutant RT enzymes and
improved metabolic stability relative to II or III.
synthetically accessible from the 8-halo compounds X,
XIII, XIV,1a or the 8-amino compound XVII1a utilizing
the methods outlined in Schemes 2-5.
Ch em istr y
The synthesis of analogues containing the amino
linker is shown in Scheme 2. Palladium-mediated cross
coupling of X, XIII, or XIV with vinyltributyltin yielded
the unstable 8-vinyl compounds, which were immedi-
ately subjected to ozonolysis to afford the corresponding
aldehyde XV in good yields (57-81%). Reductive ami-
nation of aldehydes XV in methanol with NaCNBH3 and
acetic acid produced the â-nitrogen linked analogues
XVI.16 A directly analogous procedure was used to
produce the R-nitrogen linked analogues by reacting
8-amino analogue XVII with various benzaldehydes to
yield compounds XVIII.
The oxygen and sulfur linked analogues were syn-
thesized via complementary routes as shown in Scheme
3. Reduction of XV with NaBH4 afforded XIX, which
was converted to the corresponding chloride XX with
SOCl2 in CHCl3. Reaction of XX with various pheno-
lates or thiophenolates in a nonprotic solvent, such as
THF or DMSO, gave the â-oxygen or sulfur compounds
XXI. Compound XXII was produced by Baeyer-Villiger
oxidation of XVa followed by in situ hydrolysis. The
R-oxygen linked compounds XXIII were synthesized
from pyridinol XXII via alkylation with benzyl halides.
There were difficulties with these methods in certain
cases. For instance the key pyridyl analogues XXV
could not be efficiently produced via alkylation chem-
istry. The alkylation of XX with 4-hydroxypyridine
leads predominately to N-substitution, with only trace
amounts of the desired O-alkylated product XXV. Nu-
The synthesis of X, which was used as the starting
material for most analogues reported herein, was ac-
complished from known 3-amino-2,6-dichloropyridine11
(IV) and commercially available 2-chloronicotinyl chlo-
ride12 (V) as outlined in Scheme 1. Condensation of IV
and V in the presence of pyridine afforded VI in good
yield. The selective displacement of the 2′-chloro sub-
stituent of the pyridinecarboxamide ring with ethyl-
amine produced VII which was regioselectively bromi-
nated, a result of the newly incorporated amine
functionality, to give VIII.4b,13 This was a significant
improvement over the synthesis of the 8-iodo compounds
reported in the preceding paper which required the
addition of several steps in order to manipulate a 8-nitro
group, via diazonium chemistry, to desired iodo species.1a
Formation of the diazepinone ring in the presence of
sodium hexamethyldisilazane produced IX. Use of
sodium hydride in this reaction led to debromination
as a significant side reaction.14 Compound IX was
methylated under standard conditions to give the key
8-bromo intermediate X. The 2-fluoro analogue XIII
was synthesized from X by displacement of the chloride
with p-methoxybenzylamine followed by removal of the
amine protecting group to give XII. Diazotization of XII
followed by in situ conversion to the fluoride gave XIII.15
With these intermediates in hand, we turned our
attention to the synthesis of our target compounds. All
of the modifications of the linker reported herein were

2974 J ournal of Medicinal Chemistry, 1998, Vol. 41, No. 16
Sch em e 2. Method A: Reductive Aminationa
Cywin et al.
a
(a) CH2CHSnBu3, (Ph3P)4Pd, DMF; (b) O3, CH2Cl2/MeOH followed by DMS; (c) ArNH2, AcOH, then NaCNBH3, AcOH; (d) ArCHO,
AcOH, NaCNBH3, AcOH.
Sch em e 3. Method B: Alkylationa
a
(a) SOCl2, CHCl3; (b) ArYH, base (NaH, NaHMDS, t-BuOK, etc.), DMSO or THF; (c) MCPBA, CH2Cl2 then MeOH; (d) NaH, ArCH2Br,
THF.
Sch em e 4. Method C: Nucleophilic Aromatic Substitutiona
a
(a) KH, THF, then substituted 4-nitropyridine N-oxides; (b) PCl3, CHCl3.
cleophilic aromatic substitution (Scheme 4) provided a
successful alternative approach to these important
compounds. Thus, reaction of the anion of XIX with
4-nitropyridine N-oxides provided XXIV in good yields.
The parent pyridyl analogues XXV were produced via
reduction with PCl3 in CHCl3 of XXIV followed by basic
workup.
via acylation with benzoyl chloride followed by alkyla-
tion with MeI.
Biologica l Resu lts
The results obtained from testing the analogues
against wild-type (WT) RT along with Y181C and Y188L
mutant RT in a purified enzyme assay are presented
in Table 1. Early on it was decided to focus on
compounds with the 2-chloro substituent which im-
proved mutant RT enzyme potency profiles in the alkyl
linked series. The first question addressed was whether
a heteroatom would be tolerated in the linker at the
8-position. It was found that the â-position is the
The amide linked analogues were synthesized as
described in Scheme 5. Oxidation of XIXa with J ones
reagent gave the starting acid XXVI. Amide 5 was
synthesized in two steps from XXVI by treatment with
oxalyl chloride followed by addition of N-methylaniline
in 65% overall yield. Amide 6 was produced from XVII

Inhibitors of HIV-1 Reverse Transcriptase. 8
J ournal of Medicinal Chemistry, 1998, Vol. 41, No. 16 2975
Sch em e 5. Method D: Acylationa
electron withdrawing groups such as fluoro ortho or
para substitution is preferred (see compounds 9-14).
Inhibitors with a meta hydrogen bond donor, especially
nitrogen, display improved potency against Y188L
mutant (see compounds 18-20, 24). In the preceding
paper the mutant RT activity profile of the phenyl series
was paralleled in the pyridyl series. However when
pyridyl compound 29 was tested against the Y188L
mutant it showed diminished activity relative to that
of II. In the previously described alkyl linked series the
2-fluoro substituent improved potency vs the Y188L
mutant.1a The 2-fluoro compound 28, however, showed
only marginally improved activity against the Y188L
mutant. This information clearly showed a divergent
SAR of the alkyl linked analogues compared to those
reported here. We further investigated the pyridyl
series with an emphasis on improving the Y188L
activity while maintaining potency against the other RT
enzymes. In the alkyl linked series there was a prefer-
ence for the pyrid-4-yl compound II which was the most
potent of the pyridine isomers. The 3-pyridyl analogue
26, however, showed virtually identical activity against
the Y181C and Y188L mutants. We were able to
improve Y188L mutant RT potency by incorporating
electron donating meta substitution as shown with
2-methylpyridyl compound 30. The trifluoromethyl
analogue 31 and the N-oxides 32-36 displayed reduced
potency against Y188L relative to 30, consistent with a
preference for an electron rich aromatic ring at the
8-position.
Since there was divergent SAR in the â-oxygen linked
series we decided to examine the effect of â-sulfur
substitution on the linker of II. Interestingly, the
phenylthiomethyl compound 37 proved to be among the
most potent nonnucleoside RT inhibitors reported. It
displayed IC50’s of ∼100 nM or less against all mutants
tested. Sulfur oxidation products 38 and 39 showed
reduced activity especially against the Y188L mutant.
The trend of the phenyl moiety being preferred over the
pyridyl ring continued in this series as well with 41
showing weaker activity against the Y188L mutant.
Compounds 42 and 43, however, were quite potent
against Y188L RT. Both compounds have a nitrogen
in the equivalent of the meta position which is consis-
tent with trends of the other series.
a
(a) (COCl)2, CHCl3; (b) N-methylaniline, CH2Cl2; (c) PhCOCl,
DIPEA, CH2Cl2; (d) NaH, MeI, DMF.
preferred site for substitution with heteroatoms on the
linker as demonstrated by compounds 1-4 (Table 1).
The R-amino compound 1 showed no inhibition of
Y188L, and the R-oxygen analogue 3 was a completely
ineffective inhibitor at 1 µM against either of the two
mutants tested. The â-oxygen linked analogue 4 showed
better potency vs Y188L mutant RT than the â-amino
analogue 3. The next question addressed was whether
there could be an improvement in the potency of the
analogues with nitrogen containing linkers by introduc-
ing rigidity either by substitution or by adding oxidation
on the linker. Compounds 5-7 were synthesized to
answer this question. The N-methyl analogue 7 did not
show improvement against Y188L RT and was signifi-
cantly weaker against Y181C. In the preceding paper
it was reported that the cis-olefin geometry of the two
carbon linker was preferred. It was found that second-
ary amides in the 8-position are very weak inhibitors
(<40% inhibition at 1 µM against all three enzymes of
the primary screen).17 The lack of activity was at-
tributed to these amides adopting a transoid geometry
of the aromatic ring at the 8-position relative to the
tricyclic nucleus. The tertiary amides 5 and 6 were
synthesized in order to bias the amide geometry to
mimic the cis-olefin linker. Although these compounds
were an improvement relative to the secondary amides,
none of these amide analogues improved potency against
the Y188L mutant relative the â-oxygen analogue 4.
Secon d a r y Tests
It was clear that â-oxygen analogue 4 was the best of
the first group of compounds tested with submicromolar
activity against all three enzymes. In fact 4 proved to
be slightly more potent against the Y188L mutant (0.64
vs 0.96 µM) than the analogous phenethyl derivative
III.1a We examined the SAR of the phenyl ring of 4.
Compounds 10-25 showed trends very similar to those
reported for the alkyl linked counterparts. The trend
of substitution at the meta position being preferred
continued in this series with compounds 10 and 20
having potencies very comparable to that of 4. One
notable exception was the m-dimethylamino analogue
22. There was a trend in WT-RT activity displayed by
substituted phenyloxymethyl groups at the 8-position
that suggested an electronic component to the phenyl
ring in the pharmacophore of the inhibitor. It was
noticed that with electron donating substituents, such
as hydroxyl, the preferred position is meta while with
Compounds with good profiles in the primary screen-
ing against the WT, Y181C, and Y188L enzymes were
further evaluated for in vitro metabolic stability in
human liver microsomes,18 cytotoxicity,19 and activity
against a panel of mutant RT enzymes.19 Nevirapine
(I) itself has a very slow rate of metabolism in human
liver microsomes (2 (pmol/min)/mg of microsomal pro-
tein) and low cytotoxicity (>500 µM).
The in vitro metabolism data for some representative
examples are shown in Table 2. Compound II, which
served as the benchmark for this work, was metabolized
at a rate of 145 (pmol/min)/mg of microsomal protein.
It should be noted that II was metabolized significantly
faster than nevirapine (I) in this in vitro microsomal
assay. However, the rate in this assay was virtually
identical to delavirdine (U-90152), the only other ap-
proved NNRTI.20 The â-oxygen linked analogues all

2976 J ournal of Medicinal Chemistry, 1998, Vol. 41, No. 16
Ta ble 1. Inhibition of HIV-1 RT
Cywin et al.
IC50 (µM) or % inhibition at 1 µM
no.
R1
R2
method
WT RT
Y181C RT
Y188L RT
II
III
1
2
3
4
5
6
7
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
H
CH2CH2(pyrid-4-yl)
CH2CH2Ph
NHCH2Ph
CH2NHPh
OCH2Ph
0.08
0.05
0.26
0.08
20%
0.11
15%
0.21
0.59
0.06
0.10
0.13
0.21
0.17
24%
0.28
25%
0.70
0.80
0.09
0.13
0.05
0.17
0%
0.10
0.33
0.31
0.19
0.02
0.05
0.07
0.03
0.04
0.21
0.03
0.23
0.10
0.12
0.02
0.07
0.10
0.03
0.02
0.07
0.05
0.12
0.15
0.39
0.37
0%
0.06
20%
22%
18%
0.100
0.35
0.25
27%
0.57
11%
1.66
2%
23%
33%
0.55
0.28
0.10
0.35
0%
0.28
0.71
0.09
0.26
0.14
0.19
0.26
0.03
0.07
1.34
0.30
39%
0.21
0.27
0.01
0.14
0.06
0.06
0.05
0.09
0.07
1.85
0.96
0%
28%
0%
0.64
46%
13%
17%
19%
15%
0.78
21%
13%
16%
16%
2%
A
A
B
B
D
D
B
A
B
B
B
B
B
B
B
B
B
Ba
Bb
Bc
B
B
B
B
B
B
C
C
C
C
C
C
C
C
C
C
B
Bd
Bd
B
B
B
B
CH2OPh
C(O)N(CH3)Ph
N(CH3)C(O)Ph
CH2N(CH3)Ph
CH2NH(Ph-m-NH2)
CH2O(Ph-o-OH)
CH2O(Ph-m-OH)
CH2O(Ph-p-OH)
CH2O(Ph-o-F)
CH2O(Ph-m-F)
CH2O(Ph-p-F)
CH2O(Ph-o-CO2Me)
CH2O(Ph-m-CO2Me)
CH2O(Ph-p-CO2Me)
CH2O(Ph-m-CO2H)
CH2O(Ph-m-CONH2)
CH2O(Ph-m-NH2)
CH2O(Ph-m-NO2)
CH2O(Ph-m-NMe2)
CH2O(Ph-m-OMe)
CH2O(indol-4-yl)
CH2O(indol-5-yl)
CH2O(pyrid-3-yl)
CH2O(pyrid-4-yl)
CH2O(pyrid-4-yl)
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
11%
0%
20%
0.34
0.37
0%
7%
34%
1.36
28%
16%
5.52
30%
17%
0.23
45%
0%
F
Cl
Cl
Cl
H
CH2O(pyrid-4-yl)
CH2O(2-methylpyrid-4-yl)
CH2O(2-trifluoromethylpyrid-4-yl)
CH2O(pyrid-4-yl N-oxide)
CH2O(pyrid-4-yl N-oxide)
CH2O(pyrid-4-yl N-oxide)
CH2O(2-methylpyrid-4-yl N-oxide)
CH2O(2-trifluoromethylpyrid-4-yl N-oxide)
CH2SPh
CH2S(O)Ph
CH2SO2Ph
CH2S(pyrimidin-2-yl)
CH2S(pyrid-4-yl)
CH2S(purin-6-yl)
F
31%
0%
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
4.31
34%
0.03
2.42
11.0
30%
42%
0.13
0.12
CH2S(1H-pyrazolo[3,4-d]pyrimidin-4-yl)
a
b
From 16 by treatment with LiOH. From 18 by treatment with (COCl)2 followed by NH3. c From 21 by treatment with SnCl2/HCl.
d
From 37 by treatment with MCPBA.
showed a reduced rate of metabolism relative to the
analogous previously reported ethyl linked analogues
supporting the initial hypothesis leading to the design
of these compounds. The phenoxymethyl compound 4
showed a rate similar to II and half that of the
phenethyl analogue III,1a while displaying a marginal
improvement in the enzymatic profile. Major metabo-
lites of 4 were identified as phenyl ring hydroxylated
derivatives. The potent m-hydroxyphenyl analogue 10
was unfortunately metabolized nearly twice as fast as
4. The pyridyloxymethyl series, represented by com-
pounds 28 and 29, showed a marked improvement in
their rate of in vitro metabolism. The primary metabo-
lites of 28 and 29 were identified as the N-oxides by
LC-MS and comparison to authentic samples. The
N-oxide 33 was metabolized at a rate approximately 5
times slower than 28. In contrast to the â-oxygen
substitution, the â-sulfur substitution increased the rate
of in vitro metabolism relative to II. Compound 37 was
consumed at rate approximately 3 times faster than 4.
The sulfone 39, which was identified as a metabolite of
37, was metabolized at nearly twice the rate relative to
4. Replacement of the phenyl ring of 37 with hetero-
cycles did not result in a significant improvement in
rates of metabolism (compounds 41-43 vs compound
37).
A few compounds were tested for in vivo metabolism
in rat. The pyridyloxymethyl compounds 28 and 29

Inhibitors of HIV-1 Reverse Transcriptase. 8
J ournal of Medicinal Chemistry, 1998, Vol. 41, No. 16 2977
Ta ble 2. In Vitro Metabolism in Human Liver Microsomes
Ta ble 4. Mutant HIV-1 RT Panel Data
[(pmol/min)/mg of
microsomal protein]
[(pmol/min)/mg of
microsomal protein]
no. K103N (µM) V106A (µM) G190A (µM) P236L (µM)
no.
no.
I
II
III
2
4
18
23
27
28
29
37
1.85
0.12
0.05
0.05
0.02
0.19
0.13
0.05
0.04
0.07
0.03
1.48
0.55
0.84
0.51
0.21
0.16
0.22
0.30
0.13
0.18
0.06
3.93
0.03
0.12
0.80
0.01
0.04
NTa
0.01
0.05
0.12
0.04
0.08
0.11
0.71
0.23
0.08
0.14
0.29
0.08
0.11
0.22
0.05
I
II
III
4
10
12
19
20
24
25
28
2
145
288
171
318
264
292
95a
208
177
41
29
30
31
33
37
39
41
42
43
53
371
206
9
554
322
372
591
336
144
U-90152
a
NT) not tested.
a
Nonlinear rate.
Ta ble 5. Inhibition of HIV-1IIIB Replication in C8166 Cells
Ta ble 3. MTT Toxicity Assay
no.
IC50 (nM)a
IC90 (nM)b
no.
CC30 (µM)
no.
CC30 (µM)
4
20
29
37
50
19
6
113
36
24
2
4
8
10
18
19
20
24
>60
>60
60
∼50
250
130
60
27
28
29
30
37
38
42
43
>256
160
>120
>256
>60
45
5
13
a
Inhibitory concentration of compound producing a 50% reduc-
b
tions in the centers of syncytia. Inhibitory concentration of
compound producing a 90% reductions in the centers of syncytia.
See ref 4a.
25
40
>30
ity. The compound was further investigated in the
Chow and Hirsch protocol which tests the ability of
compounds or mixtures of compounds to eradicate HIV-1
virus from chronically infected peripheral blood mono-
nuclear cell (PBMC) cultures.21 Compound 37 alone,
at 5 µM, effectively suppressed viral replication and p24
levels from the cell cultures fell to or below background
level by the fourth week of treatment. No virus
breakthrough was observed during the 6 weeks follow-
ing drug removal at week 7. Qualitative PCR, which
was able to detect 1 copy of HIV gene per approximately
7600 noninfected cells, showed no HIV-1 specific DNA’s
from these cultures.22
showed a metabolic profile similar to that observed in
the in vitro studies with the N-oxides of the 8-pyridyl
moiety being the predominant metabolite. The bio-
availabilities of 28 and 29 were found to be 69 ( 9%
and 57 ( 6%, respectively, in this system. The bio-
availability of the phenylthiomethyl derivative 37 was
below quantitation limits in this assay. The observed
drop in bioavailability for 37 could be suggested by rate
of in vitro metabolism in rat which was 2831 (pmol/min)/
mg of rat microsomal protein which was approximately
10 times faster than either 28 or 29 (224 and 296 (pmol/
min)/mg for 28 and 29 respectively).
Due to some observations of toxicity associated with
2-substituted analogues all compounds were screened
in an MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltet-
razolium bromide] cellular assay.1b,19 The cytotoxicity
of the 8-substituted series in general is relatively low
with most displaying CC30’s above 60 µM. Compounds
with a m-amino or m-hydroxy aromatic substituent did
exhibit a trend toward increased toxicity (Table 3,
compounds 8, 10, and 20), as did the arylthiomethyl
series. Compounds 42 and 43 which are two of the more
potent compounds were among the most toxic of those
reported here. The purinylthiomethyl analogue 42 was
the most toxic of the compounds reported herein but still
is relatively less toxic than the highly potent but toxic
2-azaindole series reported previously which were ap-
proximately 6 µM in the MTT assay.1b
With a goal to develop a broad spectrum RT inhibitor,
we further evaluated many compounds against a panel
of mutant RT enzymes. Although, in general, the
Y188L was the most resistant of the mutant RT
enzymes tested, some compounds with relatively weak
Y188L activity still displayed good activity against
several other clinically significant mutants (see Table
4). Compounds 4 and 37 showed excellent activity
against all mutants tested and showed no activity
against calf thymus DNA polymerase-R at 50 µg/mL.4a,17
The phenylthiomethyl analogue 37 was the most potent
compound and showed excellent broad spectrum activ-
A select few compounds including 37 were tested for
their ability to inhibit syncytia formation in cell cultures
infected with wild-type HIV-1IIIB virus (Table 5).4a
Activity in cell culture correlated well with the enzyme
data, and all compounds tested showed activity in cell
culture. Compound 37 was again the most potent
among those tested with an IC90 of 13 nM but the
4-pyridyloxymethyl analogue 29 also was quite potent
in this assay with an IC90 of 24 nM.
Con clu sion
The multidrug or cocktail approach for the treatment
of HIV-1 infection has shown great promise.4,5 However
with the emergence of resistance there will be a
continued need for pharmaceuticals with improved
profiles for use in the cocktails of the future. We have
shown that the 2-halo-8-aryloxymethyl- and the 2-halo-
8-arylthiomethyl-5,11-dihydro-11-ethyl-5-methyl-6H-
dipyrido[3,2-b:2′,3′-e][1,4]diazepin-6-ones are effective
inhibitors of wild-type and clinically relevant mutant
RT enzymes. The 8-aryloxymethyl compounds possess
improved activity and metabolic stability relative to the
ethyl linked analogues while maintaining low cytotox-
icity. These attributes are prerequisites to the develop-
ment of new therapeutics and progress in this regard
will be the subject of future reports.

2978 J ournal of Medicinal Chemistry, 1998, Vol. 41, No. 16
Cywin et al.
was carefully diluted with H2O and filtered, and the solid was
Exp er im en ta l Section
washed with petroleum ether and dried to give X (4.45 g,
Gen er a l Ch em ica l Meth od s. Chromatography was per-
formed on silica gel. Melting points were determined on a
Fisher-J ohns melting point apparatus in celsius (°C) and are
uncorrected. 1H NMR spectra were recorded in CDCl3 at 270
1
88%): mp 190-192; H NMR 8.42 (d, J ) 2.5, 1H), 8.19 (d, J
) 2.5, 1H), 7.44 (d, J ) 8.2, 1H), 7.12 (d, J ) 8.2, 1H), 4.13 (q,
J ) 7.0, 2H), 3.48 (s, 3H), 1.24 (t, J ) 7.0, 3H); CIMS (CH4)
367 (MH+). Anal. (C14H12BrClN4O) C, H, N.
MHz on
a Bruker AC-270 referencing to solvent unless
(f) 8-Br om o-5,11-d ih yd r o-11-eth yl-2-(((4-m eth oxyp h en -
yl)m eth yl)a m in o)-5-m eth yl-6H-d ip yr id o[3,2-b:2′,3′-e][1,4]-
d ia zep in -6-on e (XI). A pressure tube was charged with X
(3.7 g, 10 mmol), p-methoxybenzylamine (3 mL, 23 mmol), and
1,4-dioxane (15 mL), sealed, and heated to 170 °C in a sand
bath. An additional 1 mL of the amine was added each day.
After 4 days the mixture was cooled, diluted with saturated
aqueous NH4Cl and extracted with EtOAc. The organics were
washed with H2O, saturated aqueous NH4Cl and brine, then
dried over MgSO4, and concentrated. The residue was purified
by flash chromatography (EtOAc/hexanes) followed by recrys-
tallization from EtOAc/hexanes to give XI (2.2 g, 47%): mp
151-154; 1H NMR 8.36 (d, J ) 2.3, 1H), 8.15 (d, J ) 2.3, 1H),
7.26 (d, J ) 8.6, 2H), 7.24 (d, J ) 8.7, 1H), 6.87 (d, J ) 8.6,
2H), 6.17 (d, J ) 8.7, 1H), 4.78 (t, J ) 5.5, 1H), 4.41 (d, J )
5.5, 1H), 4.04 (q, J ) 7.0, 1H), 3.80 (s, 3H), 3.41 (s, 3H), 1.20
(t, J ) 7.0, 3H); CIMS (CH4) 468 (MH+). Anal. (C22H22BrN5O2)
C, H, N.
otherwise noted with J values reported in hertz. Mass spectra
were performed by Oneida Laboratories, Oneida, NY. High-
resolution mass spectra were performed by the Department
of Analytical Sciences of Boehringer Ingelheim Pharmaceuti-
cals. Elemental analyses were performed by either Midwest
Microanalytical Laboratories, Indianapolis, IN, or Quantitative
Technologies, Inc., Whitehouse, NJ .
P r ep a r a tion of 2-Ha lo-8-br om o-5,11-d ih yd r o-11-eth yl-
5-m eth yl-6H-d ip yr id o[3,2-b:2′,3′-e][1,4]d ia zep in -6-on e De-
r iva tives X a n d XIII. (a ) N-(2,6-Dich lor o-3-p yr id in yl)-2-
ch lor o-3-p yr id in eca r boxa m id e (VI). 3-Amino-2,6-dichlo-
ropyridine11 (IV) (48.9 g, 0.30 mol) was dissolved in 1,4-dioxane
(170 mL), and cyclohexane (110 mL) and pyridine (24.3 mL,
0.30 mol) were added. The 2-chloronicotinoyl chloride12 (V)
(52.8 g, 0.3 mol) in 1,4-dioxane (85 mL) was then added
dropwise over a 1 h period. The resultant white suspension
was stirred for 16 h and filtered. The solid was washed with
H2O, 1:1 hexanes/EtOAc (200 mL each), suspended in 1:1 CH2-
Cl2/H2O (2 L), stirred for 1 h and refiltered. The CH2Cl2 layer
was separated and concentrated, and the combined solid was
washed with H2O, EtOAc, and hexanes (150 mL each) and
dried in vacuo at 60 °C to afford VI (72.7 g, 80%): mp 197-
198; 1H NMR 8.98 (br s, 1H), 8.90 (d, J ) 8.5, 1H), 8.58 (dd, J
) 4.8, 1.9, 1H), 8.31 (dd, J ) 7.7, 1.9, 1H), 7.46 (dd, J ) 7.7,
4.8, 1H), 7.36 (d, J ) 8.5, 1H); CIMS (CH4) 302 (MH+). Anal.
(C11H6Cl3N3O) C, H, N.
(g) 2-Am in o-8-br om o-5,11-d ih yd r o-11-eth yl-5-m eth yl-
6H-d ip yr id o[3,2-b:2′,3′-e][1,4]d ia zep in -6-on e (XII). Com-
pound XI (2.2 g, 4.7 mmol) was dissolved in TFA (25 mL). The
mixture turned gradually orange and then red. The excess
TFA was removed by rotary evaporation. To the yellow-orange
residue was added 3% aqueous NH4OH, and after 3 h the
mixture was extracted with EtOAc and the organic layer was
washed with brine, dried over MgSO4, and concentrated. The
resulting solid was recrystallized (EtOAc/hexanes) to afford
(b) N-(2,6-Dich lor o-3-p yr id in yl)-2-eth yla m in o-3-p yr i-
d in eca r boxa m id e (VII). A mixture of VI (12.0 g, 39.8 mmol),
ethylamine (3.6 g, 80.7 mmol), and 30 mL of xylenes in a sealed
vessel was heated at 165 °C for 6 h. The reaction mixture
was cooled to room temperature and diluted with H2O, and
the mixture was extracted with EtOAc. The organic layer was
dried over MgSO4 and concentrated, and the resulting solid
was washed with EtOAc and hexanes to give VII (7.4 g, 60%),
1
XII (0.949 g, 58%): mp 204-208; H NMR 8.36 (d, J ) 2.6,
1H), 8.16 (d, J ) 2.6, 1H), 7.27 (d, J ) 8.5, 1H), 6.29 (d, J )
8.7, 1H), 4.39 (br s, 2H), 4.04 (q, J ) 7.0, 1H), 3.43 (s, 3H),
1.22 (t, J ) 7.0, 3H); CIMS (CH4) 348 (MH+). Anal. (C14H14
BrN5O) C, H, N.
-
(h ) 5,11-Dih yd r o-11-eth yl-2-flu or o-8-br om o-5-m eth yl-
6H-dipyr ido[3,2-b:2′,3′-e][1,4]diazepin -6-on e (XIII). A plas-
tic centrifuge tube was charged with XII (0.50 g, 1.4 mmol).
HF‚pyridine (10 mL) was added, and the resulting suspension
was cooled to 0 °C. NaNO2 was added in several portions over
10 min to produce a purple solution. The mixture was then
capped and stirred for 16 h. The reaction mixture was poured
onto ice and 6 N NaOH. EtOAc was added, and the mixture
was filtered. The filtrate was separated, and the organic layer
was washed with brine, dried over MgSO4, and concentrated.
Purification by flash chromatography (EtOAc/hexanes) and
recrystallization (EtOAc/hexanes) afforded XIII (0.44 g,
1
suitable for use in the next reaction: mp 110-112; H NMR
8.76 (d, J ) 8.0, 1H), 8.33 (dd, J ) 4.8, 1.7, 1H), 8.19 (s, 1H),
7.96 (br s, 1H), 7.74 (dd, J ) 7.8, 1.7, 1H), 7.33 (d, J ) 8.0,
1H), 6.58 (dd, J ) 7.8, 4.83, 1H), 3.54 (m, 2H), 1.28 (t, J ) 7.0,
3H); CIMS (CH4) 311 (MH+). Anal. (C13H12Cl2N4O) C, H, N.
(c) N-(2,6-Dich lor o-3-p yr id in yl)-5-br om o-2-eth yla m in o-
3-p yr id in eca r boxa m id e (VIII). To a solution of VII (7.4 g,
24 mmol) and KOAc (2.8 g, 28 mmol) in 90 mL of AcOH was
added Br2 (1.2 mL, 23 mmol). After 15 min, the reaction
mixture was diluted with H2O, and the precipitate was
collected by suction filtration to give VIII (8.2 g, 88%), suitable
for use in the next reaction: mp 195-196; 1H NMR 8.69 (d, J
) 8.5, 1H), 8.33 (d, J ) 2.3, 1H), 8.09 (br s, 1H), 7.89 (br s,
1H), 7.79 (d, J ) 2.3, 1H), 7.34 (d, J ) 8.5, 1H), 3.51 (m, 2H),
1
87%): mp 154-156; H NMR 8.41 (d, J ) 2.3, 1H), 8.20 (d, J
) 2.3, 1H), 7.58 (app. t, J ) 8, 1H), 6.74 (dd, J ) 8.5, 3.8,
1H), 4.11 (q, J ) 7.0, 1H), 3.49 (s, 3H), 1.262 (t, J ) 7.0, 3H);
CIMS (CH4) 351 (MH+). Anal. (C14H12BrFN4O) C, H, N.
1.27 (t, J ) 7.2, 3H); CIMS (CH4) 389 (MH+). Anal. (C13H11
BrCl2N4O) C, H, N.
-
Meth od A. P r ep a r a tion of 2-Ch lor o-5,11-d ih yd r o-11-
et h yl-8-for m yl-5-m et h yl-6H -d ip yr id o[3,2-b:2′,3′-e][1,4]-
d ia zep in -6-on e (XVa , R1 ) Cl). A solution of X (R1 ) Cl, X
) Br) (4.50 g, 12.2 mmol) in DMF (50 mL) was treated with
Pd(PPh3)4 (0.28 g, 24 mmol) followed by vinyltributyltin (3.8
mL, 12.9 mmol) and heated to 90 °C with stirring. After 2.5
h the mixture was poured into H2O and extracted with CH2-
Cl2 (4 × 100 mL) and EtOAc (2 × 100 mL). The combined
organics were washed with 15% aqueous NH4OH (2 × 100 mL)
and brine (2 × 100 mL), then dried over Na2SO4, and
concentrated, and the gross impurities were removed by rapid
flash chromatography (gradient hexanes to EtOAc) to give the
unstable 2-chloro-5,11-dihydro-11-ethyl-5-methyl-8-vinyl-6H-
dipyrido[3,2-b:2′,3′-e][1,4]diazepin-6-one (100%) which was
dissolved in 1:1 CH2Cl2/MeOH (40 mL) and cooled to -78 °C.
This solution was then saturated with ozone, and a stream of
ozone was bubbled through for 10 min more while stirring.
The mixture was warmed to ambient temperatures and
quenched with excess dimethyl sulfide. The mixture was then
concentrated, and the residue was purified by flash chroma-
(d ) 8-Br om o-2-ch lor o-5,11-d ih yd r o-11-eth yl-6H-d ip y-
r id o[3,2-b:2′,3′-e][1,4]d ia zep in -6-on e (IX). To a solution of
VIII (5.9 g, 15 mmol) in 30 mL of pyridine at 50 °C under
argon was added by syringe a 1.0 M solution of sodium
hexamethyldisilazide in THF (31.5 mL, 31.5 mmol). After 10
min, the reaction mixture was diluted with ice water and
allowed to stir for 2 h. The resultant orange-yellow precipitate
was collected by suction filtration and air-dried to give IX (4.9
g, 92%): mp 262-263; 1H NMR 8.48 (d, J ) 2.5, 1H), 8.25 (d,
J ) 2.5, 1H), 8.04 (br s, 1H), 7.25 (d, J ) 8.1, 1H), 7.05 (d, J
) 8.1, 1H), 4.18 (q, J ) 7.0, 2H), 1.24 (t, J ) 7.0, 3H); CIMS
(CH4) 353 (MH+). Anal. (C13H10BrClN4O) C, H, N.
(e) 8-Br om o-2-ch lor o-5,11-d ih yd r o-11-eth yl-5-m eth yl-
6H-d ip yr id o[3,2-b:2′,3′-e][1,4]-d ia zep in -6-on e (X). To a
solution of IX (4.9 g, 14 mmol) in DMF (140 mL) was added
NaH (0.86 g, 18 mmol), and the mixture was heated to 50 °C
for 30 min. The mixture was cooled to room temperature and
treated with MeI (0.90 mL, 15 mmol). After 1.5 h, the mixture

Inhibitors of HIV-1 Reverse Transcriptase. 8
J ournal of Medicinal Chemistry, 1998, Vol. 41, No. 16 2979
tography (gradient of hexanes to 1:1 hexanes/EtOAc) to give
XVa (1.9 g, 81%): mp 199-201; H NMR 10.00 (s, 1H), 8.84
(d, J ) 2.3, 1H), 8.56 (d, J ) 2.3, 1H), 7.48 (d, J ) 8.3, 1H),
7.18 (d, J ) 8.3, 1H), 4.29 (q, J ) 7.0, 2H), 3.49 (s, 3H), 1.31
(t, J ) 7.0, 3H); CIMS (CH4) 317 (MH+). Anal.(C15H13ClN4O2)
C, H, N.
5,11-Dih yd r o-11-eth yl-2-flu or o-8-for m yl-5-m eth yl-6H-
d ip yr id o[3,2-b:2′,3′-e][1,4]-d ia zep in -6-on e (XVb, R1 ) F ).
Starting from XIII by a procedure analogous to that used for
preparation of XVa : 72%; mp 133-134; 1H NMR 10.00 (s, 1H),
8.84 (d, J ) 2.3, 1H), 8.57 (d, J ) 2.3, 1H), 7.63 (dd, J ) 8.5,
7.0, 1H), 6.80 (dd, J ) 8.5, 3.9, 1H), 4.26 (q, J ) 7.0, 2H), 3.50
(s, 3H), 1.32 (t, J ) 7.0, 3H); CIMS (CH4) 301 (MH+). Anal.
(C15H13FN4O2) C, H, N.
mmol) was dissolved in CH2Cl2 (10 mL) and treated with
MCPBA (80 wt %, 1.04 g, 4.83 mmol). The mixture was stirred
for 16 h, then treated with MeOH, and stirred for 8 h more.
The mixture was diluted with saturated aqueous NaHCO3 (20
mL) and extracted with CH2Cl2 (3 × 25 mL). The combined
organics were washed with saturated aqueous NaHCO3 (2 ×
20 mL), dried over Na2SO4, and concentrated, and the residue
was purified by flash chromatography (hexanes to EtOAc
gradient) to give XXII (0.37 g, 38%). The product was
recrystallized from hexanes/EtOAc: mp 236-237; 1H NMR
8.09 (d, J ) 3.1, 1H), 7.73 (d, J ) 3.1, 1H), 7.42 (d, J ) 8.3,
1H), 7.08 (d, J ) 8.3, 1H), 6.22 (br s, 1H), 4.10 (q, J ) 7.0,
2H), 3.49 (s, 3H), 1.23 (t, J ) 7.0, 3H); CIMS (CH4) 305 (MH+).
Anal. (C14H13ClN4O2) C, H, N.
1
2-Chloro-5,11-dihydro-11-ethyl-5-methyl-8-phenylmethoxy-6H-
d ip yr id o[3,2-b:2′,3′-e][1,4]d ia zep in -6-on e (3). Compound
XXII (52 mg, 0.17 mmol) was dissolved in THF and treated
with excess NaH (60 wt %) followed by benzyl bromide (40
µL, 0.34 mmol). After 24 h of stirring, the mixture was cooled
to 0 °C, and the excess NaH was quenched by the dropwise
addition of H2O, and the resulting solution was extracted with
CH2Cl2 (3 × 20 mL) The combined organics were dried over
MgSO4 and concentrated, and the residue was purified by
chromatography (hexanes to 1:1 hexanes/EtOAc gradient)
followed by crystallization from hexanes to give 3 (35 mg,
P r ep a r a tion of Com p ou n d s XVI. 2-Chloro-5,11-dihydro-
11-ethyl-5-methyl-8-(phenylamino)methyl-6H-dipyrido[3,2-b:
2′,3′-e][1,4]diazepin-6-one (2) (R1 ) Cl, Ar ) Ph). Compound
XVa (50 mg, 0.16 mmol) was dissolved/suspended in MeOH
(2 mL) and treated with NaBH3CN (30 mg, 0.47 mmol)
followed by aniline (43 µL, 4.7 mmol). The mixture was stirred
for 5 min, and then AcOH (20 µL, 0.35 mmol) was added. After
an additional 3 h at room temperature the mixture was made
alkaline with 15% aqueous NaOH, and the white suspension
was extracted with CH2Cl2 (3 × 10 mL). The combined
organics were washed with brine, dried over Na2SO4, and
concentrated. The residue was purified by column chroma-
tography (hexanes to 1:1 hexanes/EtOAc gradient) to give 2
(31 mg, 50%): mp 79-80; 1H NMR 8.40 (d, J ) 2.4, 1H), 8.09
(d, J ) 2.4, 1H), 7.41 (d, J ) 8.3, 1H), 7.15 (dd, J ) 7.7, 7.5,
2H), 7.08 (d, J ) 8.3, 1H), 6.72 (t, J ) 7.5, 1H), 6.59 (d, J )
7.7, 2H), 4.31 (s, 2H), 4.16 (q, J ) 7.0, 2H), 3.47 (s, 3H), 1.57
(br s, 1H), 1.26 (t, J ) 7.0, 3H); CIMS (CH4) 394 (MH+). Anal.
(C21H20ClN5O) C, H, N.
1
52%): mp 159-160; H NMR 8.17 (d, J ) 3.1, 1H), 7.70 (d, J
) 3.1, 1H), 7.42-7.32 (m, 6H), 7.07 (d, J ) 8.2, 1H), 5.07 (s,
2H), 4.10 (q, J ) 7.1, 2H), 3.48 (s, 3H), 1.23 (t, J ) 7.1, 3H);
CIMS (CH4) 395 (MH+). Anal. (C21H19ClN4O2) C, H, N.
2-Chloro-5,11-dihydro-11-ethyl-8-hydroxymethyl-5-methyl-6H-
d ip yr id o[3,2-b:2′,3′-e][1,4]d ia zep in -6-on e XIXa (R1 ) Cl).
To a solution of XVa (582 mg, 1.84 mmol) in THF (20 mL)
was added H2O (0.1 mL) followed by NaBH4 (70 mg, 1.84
mmol). The mixture was stirred for 0.5 h, then diluted with
brine (20 mL), and extracted with CH2Cl2 (3 × 30 mL). The
combined organics were dried and concentrated, and the
residue was purified by flash chromatography (gradient hex-
anes to EtOAc) to yield XIXa (R1 ) Cl) (520 mg, 89%): mp
166-168; 1H NMR 8.40 (d, J ) 2.1, 1H), 8.10 (d, J ) 2.1, 1H),
7.43 (d, J ) 8.2, 1H), 7.11 (d, J ) 8.2, 1H), 4.68 (d, J ) 5.8,
2H), 4.17 (q, J ) 7.0, 2H), 3.49 (s, 3H), 1.78 (t, J ) 5.8, 1H),
8-(3-Am in oph en ylam in o)m eth yl-2-ch lor o-5,11-dih ydr o-
11-eth yl-5-m eth yl-6H-d ip yr id o[3,2-b:2′,3′-e][1,4]d ia zep in -
6-on e (8). Compound XVa (50 mg, 0.16 mmol) was suspended
in MeOH (3 mL) and treated with m-phenylenediamine (170
mg, 1.6 mmol). The resulting solution was stirred and treated
with NaBH3CN (50 mg 0.79 mmol) followed by the dropwise
addition of AcOH (20 µL, 0.35 mmol). After an additional 2.5
h at room temperature the mixture was made alkaline with
15% aqueous NaOH and extracted with CH2Cl2 (4 × 25 mL).
The combined organics were dried over Na2SO4 and concen-
trated. The residue was purified by column chromatography
(hexanes to 1:1 hexanes/EtOAc gradient), then chromatotron
(10 to 50% 2-propanol/hexanes gradient), and finally recrys-
tallization from CH2Cl2/petroleum ether to give 8 (20 mg,
1.26 (t, J ) 7.0, 3H); CIMS (CH4) 319 (MH+). Anal. (C15H15
ClN4O2) C, H, N.
-
5,11-Dihydro-11-ethyl-2-fluoro-8-hydroxymethyl-5-methyl-6H-
d ip yr id o[3,2-b:2′,3′-e][1,4]d ia zep in -6-on e (XIXb, R1 ) F ).
By a procedure analogous to that reported for XIXa from
1
XVb: 100%; mp 77-80; H NMR 8.39 (d, J ) 2.4, 1H), 8.11
1
31%): mp 88-90; H NMR 8.39 (d, J ) 2.4, 1H), 8.08 (d, J )
(d, J ) 2.4, 1H), 7.57 (dd, J ) 8.5, 7.2, 1H), 6.71 (dd, J ) 8.5,
3.9, 1H), 4.68 (br s, 2H), 4.14 (q, J ) 7.1, 2H), 3.49 (s, 3H),
1.84 (br s, 1H), 1.27 (t, J ) 7.0, 3H); CIMS (CH4) 302 (M+).
Anal. (C15H15FN4O2) C, H, N.
2.4, 1H), 7.41 (d, J ) 8.2, 1H), 7.09 (d, J ) 8.2, 1H), 6.93 (t, J
) 8.0, 1H), 6.09-6.02 (m, 2H), 5.91 (t, J ) 1.6, 1H), 4.27 (s,
2H), 4.16 (q, J ) 7.1, 2H), 3.47 (s, 3H), 1.25 (t, J ) 7.1, 3H);
CIMS (CH4) 409 (MH+); HRMS (MH+, C21H22ClN6O) calcd
409.1544, found 438.1564. Anal. (C21H21ClN6O) C, H; N:
calcd, 20.55; found 19.44.
5,11-Dih yd r o-11-eth yl-8-h yd r oxym eth yl-5-m eth yl-6H-
d ip yr id o[3,2-b:2′,3′-e][1,4]d ia zep in -6-on e (XIXc, R1 ) H).
By a procedure analogous to that reported for XIXa from
1
P r ep a r a tion of Com p ou n d XVIII. 8-((P h en ylm eth yl)-
a m in o)m eth yl-2-ch lor o-5,11-d ih yd r o-11-eth yl-5-m eth yl-
6H -d ip yr id o[3,2-b:2′,3′-e][1,4]d ia zep in -6-on e (1). Com-
pound XVII1a (27 mg, 0.09 mmol) was suspended in MeOH (2
mL) and AcOH (10 µL, 0.18 mmol), and benzaldehyde (9 µL,
0.09 mmol) was added. The resulting solution was stirred and
treated with NaBH3CN (50 mg, 0.79 mmol) followed by the
dropwise addition of AcOH (20 µL, 0.35 mmol). The mixture
was stirred and extracted with EtOAc. The combined organics
were washed with brine, dried over MgSO4, and concentrated.
The residue was purified by column chromatography (hexanes
to 1:1 hexanes/EtOAc gradient) and recrystallization from
Et2O/petroleum ether to give 1 (18 mg, 51%): mp 141; 1H NMR
7.85 (d, J ) 3.1, 1H), 7.39-7.26 (m, 2H), 7.03 (d, J ) 8.2, 1H),
4.32 (d, J ) 5.5, 2H), 4.10-4.03 (m, 3H), 3.46 (s, 3H), 1.22 (t,
J ) 7.0, 3H); CIMS (CH4) 394 (MH+). Anal. (C21H20ClN5O)
C, H, N.
XVc: 100%; mp 129-131; H NMR (250 MHz, DMSO) 8.36
(d, J ) 2.0, 1H), 8.21 (dd, J ) 5.0, 1.5, 1H), 7.98 (d, J ) 2.0,
1H), 7.84 (dd, J ) 8.0, 1.5, 1H), 7.26 (dd, J ) 8.0, 5.0, 1H),
5.29 (t, J ) 5.7, 1H), 4.47 (d, J ) 5.7, 2H), 4.07 (q, J ) 7.0,
1H), 3.43 (s, 3H), 1.17 (t, J ) 7.0, 3H); CIMS (CH4) 285 (MH+).
Anal. (C15H16N4O2) C, H, N.
2-Ch lor o-8-ch lor om eth yl-5,11-dih ydr o-11-eth yl-5-m eth -
yl-6H-d ip yr id o[3,2-b:2′,3′-e][1,4]d ia zep in -6-on e XXa (R1 )
Cl). Compound XIXa (R1 ) Cl) (0.52 g, 1.6 mmol) was
dissolved in CHCl3 (10 mL) and treated with SOCl2 (0.12 mL,
1.6 mmol) followed by Et3N (0.23 mL, 1.6 mmol). After 0.5 h
of stirring, the mixture was made alkaline with 15% aqueous
NaOH and diluted with brine (10 mL), and the organic layer
was separated. The aqueous layer was then extracted with
CH2Cl2 (2 × 20 mL). The combined organics were dried over
Na2SO4, filtered, and concentrated, and the residue was
purified by flash chromatography (gradient hexanes to 1:1
1
Gen er a l Meth od B. Syn th esis of 2-ch lor o-5,11-d ih y-
d r o-11-eth yl-8-h yd r oxy-5-m eth yl-6H-d ip yr id o[3,2-b:2′,3′-
e][1,4]d ia zep in -6-on e (XXII). Compound XVa (1.02 g, 3.22
hexanes/EtOAc) to give XXa (0.51 g, 93%): mp 133-134; H
NMR 8.40 (d, J ) 2.5, 1H), 8.13 (d, J ) 2.5, 1H), 7.44 (d, J )
8.3, 1H), 7.12 (d, J ) 8.3, 1H), 4.56 (s, 2H), 4.18 (q, J ) 7.0,

2980 J ournal of Medicinal Chemistry, 1998, Vol. 41, No. 16
Cywin et al.
2H), 3.49 (s, 3H), 1.27 (t, J ) 7.0, 3H); CIMS (CH4) 337 (MH+).
Anal. (C15H14Cl2N4O) C, H, N.
7.26-7.18 (m, 1H), 7.11 (d, J ) 8.3, 1H), 6.73-6.63 (m, 3H),
5.00 (s, 2H), 4.19 (q, J ) 7.0, 2H), 3.49 (s, 3H), 1.27 (t, J ) 7.0,
3H); CIMS (CH4) 413 (MH+). Anal. (C21H18ClFN4O2) C, H,
N.
2-Ch lor o-5,11-d ih yd r o-11-eth yl-8-(4-flu or op h en yloxy)-
m eth yl-5-m eth yl-6H-d ip yr id o[3,2-b:2′,3′-e][1,4]d ia zep in -
6-on e (14): 4-fluorophenol; 57%, mp 143-144; 1H NMR 8.44
(d, J ) 2.2, 1H), 8.17 (d, J ) 2.2, 1H), 7.43 (d, J ) 8.3, 1H),
7.10 (d, J ) 8.3, 1H), 7.00-6.84 (m, 4H), 4.97 (s, 2H), 4.18 (q,
J ) 7.0, 2H), 3.49 (s, 3H), 1.27 (t, J ) 7.0, 3H); CIMS (CH4)
413 (MH+). Anal. (C21H18ClFN4O2) C, H, N.
2-Ch lor o-5,11-dih ydr o-11-eth yl-5-m eth yl-8-(ph en yloxy)-
m eth yl-6H-d ip yr id o[3,2-b:2′,3′-e][1,4]d ia zep in -6-on e (4).
Phenol (18 mg, 0.19 mmol) in DMSO (4 mL) was treated with
sodium bis(trimethylsilyl)amide (1.0 M in THF, 0.19 mL, 0.19
mmol). After 10 min of stirring at ambient temperature,
compound XXa (60 mg, 0.18 mmol) was added and the mixture
was stirred for an additional hour. The mixture was quenched
with brine (5 mL) and made alkaline with 15% aqueous NaOH.
The mixture was extracted with CH2Cl2 (3 × 15 mL), the
organics were dried over Na2SO4 and concentrated, and the
residue was purified by flash chromatography (hexanes to
EtOAc gradient) to give 4 (55 mg, 78%): mp 140-141; 1H NMR
8.46 (d, J ) 2.4, 1H), 8.19 (d, J ) 2.4, 1H), 7.43 (d, J ) 8.2,
1H), 7.32-7.26 (m, 2H), 7.10 (d, J ) 8.2, 1H), 6.99-6.92 (m,
3H), 5.02 (s, 2H), 4.19 (q, J ) 7.1, 2H), 3.49 (s, 3H), 1.27 (t, J
) 7.1, 3H); CIMS (CH4) 395 (MH+). Anal. (C21H19ClN4O2) C,
H, N.
2-Ch lor o-5,11-d ih yd r o-11-et h yl-5-m et h yl-8-(N-m et h yl
p h e n y la m in o )m e t h y l-6H -d ip y r id o [3,2-b :2′,3′-e][1,4]-
d ia zep in -6-on e (7). Compound XXa (50 mg, 0.15 mmol) was
dissolved in N-methylaniline (1 mL) and stirred for 3 days.
The mixture was purified by column chromatography (hexanes
to EtOAc gradient) to give 7 (25 mg, 41%): mp foam, 55-57;
1H NMR 8.28 (d, J ) 2.4, 1H), 7.97 (d, J ) 2.4, 1H), 7.40 (d, J
) 8.3, 1H), 7.20 (br t, J ) 8.0, 2H), 7.08 (d, J ) 8.3, 1H), 6.74-
6.70 (m, 3H), 4.47 (s, 2H), 4.14 (q, J ) 7.0, 2H), 3.46 (s, 3H),
2.99 (s, 3H), 1.25 (t, J ) 7.0 3H); CIMS (CH4) 408 (MH+). Anal.
(C22H22ClN5O) C, H, N.
2-Ch lor o-5,11-dih ydr o-11-eth yl-8-(2-h ydr oxyph en yloxy)-
m eth yl-5-m eth yl-6H-d ip yr id o[3,2-b:2′,3′-e][1,4]d ia zep in -
6-on e (9). Catechol (82 mg, 0.74 mmol) in DMSO (1 mL) was
treated with t-BuOK (1.0 M in THF, 0.16 mL, 0.16 mmol). The
resulting stirred solution was treated with XXa (50 mg, 0.14
mmol), and the mixture was stirred an additional 24 h. The
mixture was diluted with EtOAc (20 mL) and washed with
brine (3 × 10 mL). The organics were dried over Na2SO4 and
concentrated, and the residue was purified by flash chroma-
tography (hexanes to EtOAc gradient) followed crystallization
from hexanes/EtOAc to give 9 (35 mg, 58%): mp 172-173; 1H
NMR 8.46 (d, J ) 2.3, 1H), 8.18 (d, J ) 2.3, 1H), 7.45 (d, J )
8.3, 1H), 7.12 (d, J ) 8.3, 1H), 6.95-6.80 (m, 4H), 5.07 (s, 2H),
4.20 (q, J ) 7.0, 2H), 3.49 (s, 3H), 1.28 (t, J ) 7.0, 3H); CIMS
(CH4) 411 (MH+). Anal. (C21H19ClN4O3) C, H, N.
2-Ch lor o-5,11-d ih yd r o-11-eth yl-8-(2-(m eth oxyca r bon -
yl)p h en yloxy)m eth yl-5-m eth yl-6H-d ip yr id o[3,2-b:2′,3′-e]-
[1,4]d ia zep in -6-on e (15): methyl salicylate; 57%; mp 196-
197; 1H NMR 8.53 (d, J ) 2.4, 1H), 8.25 (d, J ) 2.4, 1H), 7.83
(dd, J ) 7.7, 1.7, 1H), 7.49-7.42 (m, 1H), 7.43 (d, J ) 8.3,
1H), 7.11 (d, J ) 8.3, 1H), 7.05-6.99 (m, 2H), 5.12 (s, 2H),
4.19 (q, J ) 7.0, 2H), 3.91 (s, 3H), 3.49 (s, 3H), 1.27 (t, J ) 7.0,
3H); CIMS (CH4) 453 (MH+). Anal. (C23H21ClN4O4) C, H, N.
2-Ch lor o-5,11-d ih yd r o-11-eth yl-8-((3-(m eth oxyca r bon -
yl)p h en yloxy)m eth yl-5-m eth yl-6H-d ip yr id o[3,2-b:2′,3′-e]-
[1,4]d ia zep in -6-on e (16): methyl 3-hydroxybenzoate; 90%;
1
mp 163-164; H NMR 8.47 (d, J ) 2.4, 1H), 8.20 (d, J ) 2.4,
1H), 7.68-7.61 (m, 2H), 7.44 (d, J ) 8.2, 1H), 7.35 (t, J ) 7.9,
1H), 7.15-7.09 (m, 1H), 7.11 (d, J ) 8.2, 1H), 5.06 (s, 2H),
4.19 (q, J ) 7.0, 2H), 3.91 (s, 3H), 3.49 (s, 3H), 1.28 (t, J ) 7.0,
3H); CIMS (CH4) 453 (MH+). Anal. (C23H21ClN4O4) C, H, N.
2-ch lor o-5,11-dih ydr o-11-eth yl-8-(4-(m eth oxycar bon yl)-
ph en yloxy)m eth yl-5-m eth yl-6H-dipyr ido[3,2-b:2′,3′-e][1,4]-
d ia zep in -6-on e (17): methyl 4-hydroxybenzoate; 45%; mp
196-197; 1H NMR 8.46 (d, J ) 2.4, 1H), 8.18 (d, J ) 2.4, 1H),
7.99 (d, J ) 8.9, 2H), 7.43 (d, J ) 8.3, 1H), 7.11 (d, J ) 8.3,
1H), 6.95 (d, J ) 8.9, 2H), 5.07 (s, 2H), 4.19 (q, J ) 7.1, 2H),
3.88 (s, 3H), 3.49 (s, 3H), 1.27 (t, J ) 7.1, 3H); CIMS (CH4)
453 (MH+). Anal. (C23H21ClN4O4) C, H, N.
2-Ch lor o-5,11-dih ydr o-11-eth yl-5-m eth yl-8-(3-n itr oph en -
yla m in o)m eth yl-6H-d ip yr id o[3,2-b:2′,3′-e][1,4]d ia zep in -6-
on e (21): 3-nitrophenol; 95%; mp 171-172; 1H NMR 8.47 (d,
J ) 2.4, 1H), 8.20 (d, J ) 2.4, 1H), 7.86 (ddd, J ) 8.1, 1.9, 0.8,
1H), 7.79 (app t, J ) 2.3, 1H), 7.45 (t, J ) 8.1, 1H), 7.45 (d, J
) 8.3, 1H), 7.26 (ddd, J ) 8.1, 2.6, 0.8, 1H), 7.12 (d, J ) 8.3,
1H), 5.09 (s, 2H), 4.20 (q, J ) 7.1, 2H), 3.50 (s, 3H), 1.28 (t, J
) 7.1, 3H); CIMS (CH4) 440 (MH+). Anal. (C21H18ClN5O4) C,
H, N.
2-Ch lor o-5,11-d ih yd r o-11-eth yl-8-(3-(N,N-d im eth yla m i-
n o)p h en yloxy)m eth yl-5-m eth yl-6H-d ip yr id o[3,2-b:2′,3′-e]-
[1,4]d ia zep in -6-on e (22): 3-dimethylaminophenol; 65%; mp
132-133; 1H NMR 8.46 (d, J ) 2.4, 1H), 8.19 (d, J ) 2.4, 1H),
7.43 (d, J ) 8.3, 1H), 7.13 (t, J ) 8.4, 1H), 7.10 (d, J ) 8.3,
1H), 6.39-6.30 (m, 3H), 5.01 (s, 2H), 4.18 (q, J ) 7.0, 2H),
3.49 (s, 3H), 2.92 (s, 6H), 1.27 (t, J ) 7.0 3H); CIMS (CH4) 438
(MH+). Anal. (C23H24ClN5O2) C, H, N.
Com p ou n d s 10-17, 21-26, 40, 42, a n d 43 w er e p r e-
p a r ed in a n a n a logou s fa sh ion fr om th e in d ica ted
sta r tin g m a ter ia l a n d XXa .
2-Ch lor o-5,11-d ih yd r o-11-et h yl-8-(3-h yd r oxyp h en yl)-
m eth yl-5-m eth yl-6H-d ip yr id o[3,2-b:2′,3′-e][1,4]d ia zep in -6-
on e (10): resorcinol; 51%; mp 219-220; 1H NMR 8.45 (d, J )
2.3, 1H), 8.16 (d, J ) 2.3, 1H), 7.43 (d, J ) 8.3, 1H), 7.15-7.09
(m, 1H), 7.11 (d, J ) 8.3, 1H), 6.53-6.43 (m, 3H), 5.21 (s, 1H),
4.97 (s, 2H), 4.18 (q, J ) 7.0, 2H), 3.49(s, 3H), 1.26 (t, J ) 7.0,
3H); CIMS (CH4) 411 (MH+). Anal. (C21H19ClN4O3) C, H, N.
2-Ch lor o-5,11-dih ydr o-11-eth yl-8-(4-h ydr oxyph en yloxy)-
m eth yl-5-m eth yl-6H-d ip yr id o[3,2-b:2′,3′-e][1,4]d ia zep in -
2-Ch lor o-5,11-dih ydr o-11-eth yl-8-(3-m eth oxyph en yloxy)-
m eth yl-5-m eth yl-6H-d ip yr id o[3,2-b:2′,3′-e][1,4]d ia zep in -
6-on e (23): 3-methoxyphenol; 54%; mp 95-97; 1H NMR 8.46
(d, J ) 2.4, 1H), 8.18 (d, J ) 2.4, 1H), 7.43 (d, J ) 8.3, 1H),
7.18 (t, J ) 8.1, 1H), 7.10 (d, J ) 8.3, 1H), 6.55-6.48 (m, 3H),
5.00 (s, 2H), 4.18 (q, J ) 7.0, 2H), 3.78 (m, 3H), 3.49 (s, 3H),
1
6-on e (11): hydroquinone; 67%; mp 199-200; H NMR 8.44
1.27 (t, J ) 7.0, 3H); CIMS (CH4) 425 (MH+). Anal. (C22H21
ClN4O3) C, H, N.
-
(d, J ) 2.4, 1H), 8.16 (d, J ) 2.4, 1H), 7.43 (d, J ) 8.3, 1H),
7.10 (d, J ) 8.3, 1H), 6.78 (ab, ∆υ ) 13.2, J ) 9.2, 4H), 6.71 (s,
1H), 4.93 (s, 2H), 4.18 (q, J ) 7.1, 2H), 3.49 (s, 3H), 1.27 (t, J
) 7.1, 3H); CIMS (CH4) 411 (MH+). Anal. (C21H19ClN4O3) C,
H, N.
2-Ch lor o-5,11-dih ydr o-11-eth yl-8-(4-in dolyloxy)m eth yl-
5-m e t h yl-6H -d ip yr id o[3,2-b:2′,3′-e][1,4]d ia ze p in -6-on e
(24): 4-hydroxyindole; 14%; mp 183-185; 1H NMR 8.55 (d, J
) 2.4, 1H), 8.24 (d, J ) 2.4, 1H), 8.19 (br s, 1H), 7.43 (d, J )
8.3, 1H), 7.12-7.02 (m, 3H), 7.10 (d, J ) 8.3, 1H), 6.65 (t, J )
2.6, 1H), 6.56 (dd, J ) 7.1, 1.2, 1H), 5.18 (s, 2H), 4.17 (q, J )
7.1, 2H), 3.49 (s, 3H), 1.28 (t, J ) 7.1, 3H); CIMS (CH4) 434
(MH+). Anal. (C23H20ClN5O2) C, H, N.
2-Ch lor o-5,11-dih ydr o-11-eth yl-8-(5-in dolyloxy)m eth yl-
5-m e t h yl-6H -d ip yr id o[3,2-b:2′,3′-e][1,4]d ia ze p in -6-on e
(25): 5-hydroxyindole; 22%; mp 176-178; 1H NMR 8.49 (d, J
) 2.3, 1H), 8.21 (d, J ) 2.3, 1H), 7.42 (d, J ) 8.3, 1H), 7.28 (d,
J ) 8.8, 1H), 7.18 (t, J ) 2.7, 1H), 7.14 (d, J ) 2.3, 1H), 7.09
(d, J ) 8.3, 1H), 6.88 (dd, J ) 8.8, 2.3, 1H), 6.47 (d, J ) 2.7,
2-Ch lor o-5,11-d ih yd r o-11-eth yl-8-(2-flu or op h en yloxy)-
m eth yl-5-m eth yl-6H-d ip yr id o[3,2-b:2′,3′-e][1,4]d ia zep in -
6-on e (12): 2-fluorophenol; 52%; mp 109-110; 1H NMR 8.47
(d, J ) 2.2, 1H), 8.19 (d, J ) 2.2, 1H), 7.43 (d, J ) 8.4, 1H),
7.11 (d, J ) 8.4, 1H), 7.07-6.89 (m, 4H), 5.08 (s, 2H), 4.18 (q,
J ) 7.0, 2H), 3.49 (s, 3H), 1.27 (t, J ) 7.0, 3H); CIMS (CH4)
413 (MH+). Anal. (C21H18ClFN4O2) C, H, N.
2-Ch lor o-5,11-dih ydr o-11-eth yl-8-(3-flu or oph en yl)m eth -
yl-5-m e t h yl-6H -d ip yr id o[3,2-b:2′,3′-e][1,4]d ia ze p in -6-
on e (13): 3-fluorophenol; 70%; mp 104-105; 1H NMR 8.45
(d, J ) 2.2, 1H), 8.17 (d, J ) 2.2, 1H), 7.43 (d, J ) 8.3, 1H),

Inhibitors of HIV-1 Reverse Transcriptase. 8
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1H), 5.06 (s, 2H), 4.18 (q, J ) 7.0, 2H), 3.49 (s, 3H), 1.27 (t, J
) 7.0 3H); CIMS (CH4) 434 (MH+). Anal. (C23H20ClN5O2‚0.25
EtOAc) C, H, N.
7.39 (t, J ) 7.7, 1H), 7.18 (dd, J ) 7.7, 2.5, 1H), 7.11 (d, J )
8.3, 1H), 5.07 (s, 2H), 4.19 (q, J ) 7.0, 2H), 3.50 (s, 3H), 1.28
(t, J ) 7.0, 3H); CIMS (CH4) 439 (MH+). Anal. (C22H19ClN4O4)
C, H, N.
2-Ch lor o-5,11-d ih yd r o-11-eth yl-5-m eth yl-8-(3-p yr id yl-
oxy)m e t h yl-6H -d ip yr id o[3,2-b:2′,3′-e][1,4]d ia ze p in -6-
on e (26): 3-hydroxypyridine; 72%; mp 183-184; 1H NMR 8.46
(d, J ) 2.3, 1H), 8.37 (br s, 1H), 8.27 (br s, 1H), 8.19 (d, J )
2.3, 1H), 7.44 (d, J ) 8.3, 1H), 7.35 (br s, 1H), 7.12 (d, J ) 8.3,
1H), 5.09 (s, 2H), 4.19 (q, J ) 7.0, 2H), 3.49 (s, 3H), 1.28 (t, J
) 7.0, 3H); CIMS (CH4) 396 (MH+). Anal. (C20H18ClN5O2) C,
H, N.
2-Ch lor o-5,11-d ih yd r o-11-eth yl-5-m eth yl-8-(2-p yr im id i-
n ylth io)m eth yl-6H-d ip yr id o[3,2-b:2′,3′-e][1,4]d ia zep in -6-
on e (40): 6-mercaptopyrimidine; 69%; mp 163-164; 1H NMR
8.51 (d, J ) 4.8, 2H), 8.48 (d, J ) 2.5, 1H), 8.16 (d, J ) 2.5,
1H), 7.40 (d, J ) 8.3, 1H), 7.07 (d, J ) 8.3, 1H), 6.96 (t, J )
4.8, 1H), 4.32 (s, 2H), 4.13 (q, J ) 7.0, 2H), 3.46 (s, 3H), 1.24
(t, J ) 7.0, 3H); CIMS (CH4) 413 (MH+). Anal. (C19H17ClN6-
OS) C, H, N.
2-Ch lor o-5,11-d ih yd r o-11-et h yl-5-m et h yl-8-(p u r in -6-
ylt h io)m et h yl-6H -d ip yr id o[3,2-b:2′,3′-e][1,4]d ia zep in -6-
on e (42): 6-mercaptopurine; 67%; mp 148-151; 1H NMR 8.74
(s, 1H), 8.52 (d, J ) 2.5, 1H), 8.21 (d, J ) 2.5, 1H), 8.08 (s,
1H), 7.39 (d, J ) 8.2, 1H), 7.06 (d, J ) 8.2, 1H), 4.59 (s, 2H),
4.13 (q, J ) 7.1, 2H), 3.45 (s, 3H), 1.23 (t, J ) 7.0, 3H); CIMS
(CH4) 453 (MH+). Anal. (C20H17ClN8OS‚0.25 EtOAc) C, H,
N.
2-Ch lor o-5,11-dih ydr o-11-eth yl-5-m eth yl-8-(1H-pyr azolo-
[3,4-d ]p yr im id in -4-ylth io)m eth yl-6H-d ip yr id o[3,2-b:2′,3′-
e][1,4]d ia zep in -6-on e (43): 3-mercapto-1H-pyrazolo[3,4-d]-
pyrimidine; 75%; mp 128-130; 1H NMR 8.80 (s, 1H), 8.52 (d,
J ) 2.5, 1H), 8.22 (d, J ) 2.5, 1H), 8.06 (s, 1H), 7.40 (d, J )
8.3, 1H), 7.07 (d, J ) 8.3, 1H), 4.59 (s, 2H), 4.15 (q, J ) 7.0,
2H), 3.47 (s, 3H), 1.24 (t, J ) 7.0, 3H); CIMS (CH4) 453 (MH+).
Anal. (C20H17ClN8OS‚0.125DMSO) C, H, N.
8-(3-(Am in oca r bon yl)p h en yloxy)m eth yl-2-ch lor o-5,11-
d ih yd r o-11-eth yl-5-m eth yl-6H-d ip yr id o[3,2-b:2′,3′-e][1,4]-
d ia zep in -6-on e (19). Compound 16 (33 mg, 0.073 mmol) was
dissolved in THF (5 mL) and treated with aqueous LiOH
(1.0M, 73 µL, 0.073 mmol). After 16 h the mixture was diluted
with saturated aqueous NH4Cl (15 mL), extracted with EtOAc
(2 × 20 mL), dried over Na2SO4, and concentrated. The
residue was azeotropically dried with benzene (50 mL) and
used directly. The residue was dissolved in CH2Cl2 (10 mL)
and treated with oxalyl chloride (0.063 mL, 0.72 mmol)
followed by a catalytic amount of DMF (4 µL). The mixture
was stirred for 0.5 h and then concentrated in vacuo, and the
residue was dissolved in CH2Cl2 (10 mL), treated with NH3-
(g), and stirred for 5 min more. The mixture was then diluted
with EtOAc (15 mL), washed with brine (2 × 10 mL), dried
over Na2SO4, and concentrated, and the residue was purified
by chromatography (hexanes to EtOAc gradient) to give 19
(25 mg, 79%): mp 96-98; 1H NMR 8.46 (d, J ) 2.3, 1H), 8.19
(d, J ) 2.3, 1H), 7.45-7.34 (m, 3H), 7.43 (d, J ) 8.3, 1H), 7.12-
7.09 (m, 1H), 7.11 (d, J ) 8.3, 1H), 5.07 (s, 2H), 4.19 (q, J )
6.9, 2H), 3.49 (s, 3H), 1.27 (t, J ) 6.9, 3H); CIMS (CH4) 438
(MH+). Anal. (C22H20ClN5O3) C, H, N.
8-(3-Am in op h en yloxy)m et h yl-2-ch lor o-5,11-d ih yd r o-
11-eth yl-5-m eth yl-6H-d ip yr id o[3,2-b:2′,3′-e][1,4]d ia zep in -
6-on e (20). Compound 21 (80 mg, 0.18 mmol) was dissolved
in AcOH (5 mL) and treated with a solution of SnCl2‚2H2O
(154 mg, 0.68 mmol) in concentrated HCl (2 mL). After 17 h
of stirring, for the resulting mixture was made alkaline with
50% aqueous NaOH and extracted with CH2Cl2 (8 × 20 mL).
The combined organics were dried over Na2SO4, and concen-
trated, and the residue was purified by flash chromatography
(hexanes to 1:1 hexanes/EtOAc gradient) to give 20 (46 mg,
2-Ch lor o-5,11-dih ydr o-11-eth yl-5-m eth yl-8-(ph en ylth io)-
m eth yl-6H-d ip yr id o[3,2-b:2′,3′-e][1,4]d ia zep in -6-on e (37).
A solution of thiophenol (0.16 mL, 1.6 mmol) in DMF (15 mL)
was treated with NaH (60 wt %, 62 mg, 1.6 mmol). After 15
min of stirring, compound XXa (0.50 g, 1.5 mmol) was added,
and the mixture was stirred for an additional 18 h. The excess
thiolate was quenched with MeOH, and the mixture was
diluted with aqueous NaHCO3 and extracted with CH2Cl2. The
organics were dried over Na2SO4, filtered, and concentrated,
and the residue was purified by flash chromatography (hex-
anes/ethyl acetate) and recrystallization from hexanes/EtOAc
1
62%): mp 148-149; H NMR 8.44 (d, J ) 2.3, 1H), 8.16 (d, J
) 2.3, 1H), 7.43 (d, J ) 8.3, 1H), 7.10 (d, J ) 8.3, 1H), 7.04 (t,
J ) 8.0, 1H), 6.36-6.25 (d, J ) 8.3, 3H), 4.97 (s, 2H), 4.18 (q,
J ) 7.0, 2H), 3.65 (br s, 2H), 3.48 (s, 3H), 1.27 (t, J ) 7.0, 3H);
CIMS (CH4) 410 (MH+). Anal. (C21H20ClN5O2) C, H, N.
2-Chloro-5,11-dihydro-11-ethyl-5-methyl-8-(phenylsulfinyl)-
m eth yl-6H-d ip yr id o[3,2-b:2′,3′-e][1,4]d ia zep in -6-on e (38)
a n d 2-Ch lor o-5,11-d ih yd r o-11-eth yl-5-m eth yl-8-(p h en yl-
su lfon yl)m et h yl-6H -d ip yr id o[3,2-b:2′,3′-e][1,4]d ia zep in -
6-on e (39). Compound 37 (70 mg, 0.17 mmol) was dissolved
in CH2Cl2 (2.5 mL), cooled to 0 °C, and treated with MCPBA
(60 wt %, 59 mg, 0.21 mmol). After 1 h the mixture was
diluted with CH2Cl2 (20 mL) and washed with saturated
aqueous NaHCO3. The organic phase was dried and concen-
trated, and the resulting residue was purified by preparative
TLC to give 38 (8 mg, 11%) and 39 (29 mg, 39%). Data for
38: mp 96-98; 1H NMR 7.89 (br s, 1H), 7.79 (br s, 1H), 7.48-
7.38 (m, 6H), 7.13 (d, J ) 8.3, 1H), 4.14 (q, J ) 7.0, 2H), 4.26
(ab, ∆υ ) 45, J ) 13, 2H), 3.46 (s, 3H), 1.24 (t, J ) 7.1, 3H);
CIMS (CH4) 427 (MH+); HRMS (MH+, C21H20ClN4O2S) calcd
427.0995, found 427.1007. Anal. (C21H19ClN4O2S) C, H; N:
calcd, 13.12; found, 12.58. Data for 39: mp 98-100; 1H NMR
8.05 (d, J ) 2.4, 1H), 7.95 (d, J ) 2.4, 1H), 7.72-7.63 (m, 2H),
7.53-7.35 (m, 3H), 7.44 (d, J ) 8.3, 1H), 7.14 (d, J ) 8.3, 1H),
4.26 (s, 2H), 4.16 (q, J ) 7.1, 2H), 3.46 (s, 3H), 1.24 (t, J ) 7.1,
3H); CIMS (CH4) 443 (MH+). Anal. (C21H19ClN4O3S) C, H,
N.
Meth od C. Syn th esis of Com p ou n d s XXIV. 5,11-Di-
h ydr o-11-eth yl-5-m eth yl-8-((1-oxo-pyr idin -4-yl)oxy)m eth yl-
6H-d ip yr id o[3,2-b:2′,3′-e][1,4]d ia zep in -6-on e (32). Com-
pound XIXc (142 mg, 0.499 mmol) was dissolved in THF (5
mL) and was treated with excess KH followed by 4-nitropy-
ridine N-oxide (0.105 g, 0.749 mmol). The reaction mixture
was stirred for 18 h, then diluted with CH2Cl2 (20 mL), and
quenched with brine (dropwise). The organic layer was
separated, and the aqueous was extracted with CH2Cl2 (3 ×
15 mL). The combined organics were dried over Na2SO4,
filtered, and concentrated. The residue was purified by
1
to give 37 (0.378 g, 62%): mp 92-93; H NMR 8.23 (d, J )
2.4, 1H), 8.04 (d, J ) 2.4, 1H), 7.41 (d, J ) 8.3, 1H), 7.30-7.18
(m, 5H), 7.08 (d, J ) 8.3, 1H), 4.14 (q, J ) 7.0, 2H), 4.04 (s,
2H), 3.46 (s, 3H), 1.23 (t, J ) 7.0, 3H); CIMS (CH4) 411 (MH+).
Anal. (C21H19ClN4OS) C, H, N.
2-Ch lor o-5,11-d ih yd r o-11-eth yl-5-m eth yl-8-(p yr id in yl-
t h io)m e t h yl-6H -d ip yr id o[3,2-b:2′,3′-e][1,4]d ia ze p in -6-
on e (41). By a procedure analogous to that used for the
preparation of 37, and starting from XXa and 4-mercaptopy-
ridin, compound 41 was produced in 79% yield: mp 140-142;
1H NMR 8.40 (d, J ) 2.5, 1H), 8.38 (d, J ) 6.2, 2H), 8.13 (d, J
) 2.5, 1H), 7.43 (d, J ) 8.2, 1H), 7.11 (d, J ) 8.2, 1H), 7.09 (d,
J ) 6.2, 2H), 4.16 (q, J ) 7.0, 2H), 4.16 (s, 2H), 3.48 (s, 3H),
1.26 (t, J ) 7.0, 3H); CIMS (CH4) 412 (MH+). Anal. (C20H18
ClN5OS‚0.50H2O) C, H, N.
-
Mod ifica tion s to com p ou n d s syn th esized by m eth od
B: 2-Ch lor o-5,11-d ih yd r o-11-eth yl-8-(3-(ca r boxy)p h en yl-
o x y )m e t h y l-5-m e t h y l-6H -d ip y r id o [3,2-b :2′,3′-e][1,4]-
d ia zep in -6-on e (18). Compound 16 23 mg, 0.051 mmol)
was dissolved in THF (1 mL) and treated with aqueous LiOH
(1M, 2 mL, 2 mmol). The reaction was stirred until no starting
material was detected by TLC. The mixture was then acidified
to pH ) 6 with saturated aqueous NH4Cl and extracted with
CH2Cl2 (3 × 20 mL). The combined organics were dried over
Na2SO4 and concentrated, and the residue was recrystallized
from hexanes/EtOAc to give 18 (15 mg, 67%): mp 181-182;
1H NMR 8.48 (d, J ) 2.4, 1H), 8.21 (d, J ) 2.4, 1H), 7.72 (br
d, J ) 7.7, 1H), 7.66 (d, J ) 2.5, 1H), 7.44 (d, J ) 8.3, 1H),

2982 J ournal of Medicinal Chemistry, 1998, Vol. 41, No. 16
Cywin et al.
1
preparative TLC (10% MeOH/CH2Cl2), the resulting white
foam was stirred vigorously with petroleum ether for 24 h,
and the resulting white solid was collected by filtration to give
32 (115 mg, 61%): mp 218-219; 1H NMR 8.43 (d, J ) 2.4,
1H), 8.22 (dd, J ) 4.7, 1.6, 1H), 8.16 (d, J ) 2.4, 1H), 8.15 (d,
J ) 7.6, 2H), 7.51 (dd, J ) 8.0, 1.6, 1H), 7.13 (dd, J ) 8.0, 4.7,
1H), 6.85 (d, J ) 7.6, 2H), 5.05 (s, 2H), 4.22 (q, J ) 7.1, 2H),
3.52 (s, 3H), 1.28 (t, J ) 7.1, 3H); CIMS (CH4) 378 (MH+). Anal.
(C20H19N5O3) C, H, N.
5,11-Dih ydr o-11-eth yl-2-flu or o-5-m eth yl-8-((1-oxo-4-pyr -
id in yl)oxy)m eth yl-6H-d ip yr id o[3,2-b:2′,3′-e][1,4]d ia zep in -
6-on e (33). By a procedure analogous to that used for the
preparation of 32, and starting from XIXb and 4-nitropyridine
N-oxide, compound 33 was produced in 69% yield: mp 194-
196; 1H NMR 8.43 (d, J ) 2.4, 1H), 8.16 (d, J ) 2.4, 1H), 8.12
(br d, J ) 6.9, 2H), 7.59 (dd, J ) 8.4, 7.1, 1H), 6.84 (br d, J )
6.9, 2H), 6.74 (dd, J ) 8.4, 3.9, 1H), 5.05 (s, 2H), 4.16 (q, J )
7.0, 2H), 3.50 (s, 3H), 1.28 (t, J ) 7.0, 3H); CIMS (CH4) 380
(MH+ - O). Anal. (C20H18FN5O3‚0.25H2O) C, H, N.
164-165; H NMR 8.44 (br d, J ) 2.4, 3H overlaps broad s),
8.21 (dd, J ) 4.7, 1.6, 1H), 8.17 (d, J ) 2.4, 1H), 7.50 (dd, J )
8.0, 1.6, 1H), 7.12 (dd, J ) 7.9, 4.7, 1H), 6.85 (d, J ) 6.3, 2H),
5.06 (s, 2H), 4.21 (q, J ) 7.0, 2H), 3.52 (s, 3H), 1.27 (t, J ) 7.0,
3H); CIMS (CH4) 362 (MH+). Anal. (C20H19N5O2) C, H, N.
5,11-Dih yd r o-11-eth yl-2-flu or o-5-m eth yl-8-(4-pyr id in yl-
oxy)m e t h yl-6H -d ip yr id o[3,2-b:2′,3′-e][1,4]d ia ze p in -6-
on e (28). By a procedure analogous to that used for the
preparation of 27, and starting from 33, compound 28 was
produced in 81% yield: mp 146-148; 1H NMR 8.45-8.44 (m,
3H), 8.18 (d, J ) 2.3, 1H), 7.58 (dd, J ) 8.5, 7.1, 1H), 6.85 (br
d, J ) 5.0, 2H), 6.73 (dd, J ) 8.5, 3.9, 1H), 5.07 (s, 2H), 4.16
(q, J ) 7.0, 2H), 3.50 (s, 3H), 1.28 (t, J ) 7.0, 3H); CIMS (CH4)
380 (MH+). Anal. (C20H18FN5O2‚0.25H2O) C, H, N.
2-Ch lor o-5,11-d ih yd r o-11-eth yl-5-m eth yl-8-(4-p yr id yl-
oxy)m e t h yl-6H -d ip yr id o[3,2-b:2′,3′-e][1,4]d ia ze p in -6-
on e (29). By a procedure analogous to that used for the
preparation of 27, and starting from 34, compound 29 was
1
produced in 100% yield: mp 169-170; H NMR 8.45 (d, J )
2-Chloro-5,11-dihydro-11-ethyl-5-methyl-8-((1-oxo-4-pyridinyl)-
oxy)m e t h yl-6H -d ip yr id o[3,2-b:2′,3′-e][1,4]d ia ze p in -6-
on e (34). By a procedure analogous to that used for the
preparation of 32, and starting from XIXa and 4-nitropyridine
N-oxide, compound 34 was produced in 86% yield: mp 208-
210; 1H NMR 8.44 (d, J ) 2.3, 1H), 8.16 (d, J ) 2.3, 1H), 8.15
(d, J ) 7.3, 2H), 7.45 (d, J ) 8.3, 1H), 7.13 (d, J ) 8.3, 1H),
6.85 (d, J ) 7.3, 2H), 5.05 (s, 2H), 4.20 (q, J ) 7.1, 2H), 3.49
(s, 3H), 1.28 (t, J ) 7.1 3H); CIMS (CH4) 412 (MH+), 396 (MH+
- O). Anal. (C20H18ClN5O3) C, H, N.
2-Ch lor o-5,11-d ih yd r o-11-eth yl-5-m eth yl-8-((4-(2-m eth -
yl-1-oxo-p yr id in yl))oxy)m eth yl-6H-d ip yr id o[3,2-b:2′,3′-e]-
[1,4]d ia zep in -6-on e (35). By a procedure analogous to that
used for the preparation of 32, and starting from XIXa and
4-nitro-2-picoline N-oxide, compound 35 was produced in 41%
yield: mp 190-192; 1H NMR 8.43 (d, J ) 2.4, 1H), 8.16 (br s,
1H), 8.15 (d, J ) 2.4, 1H), 7.45 (d, J ) 8.3, 1H), 7.13 (d, J )
8.3, 1H), 6.84 (br s, 1H), 6.74 (br s, 1H), 5.03 (s, 2H), 4.20 (q,
J ) 7.0, 2H), 3.49 (s, 3H), 2.54 (br s, 3H), 1.26 (t, J ) 7.0, 3H);
CIMS (CH4) 426 (MH+); HRMS (MH+, C21H21ClN5O3) calcd
426.1328, found 438.1330. Anal. (C21H20ClN5O3‚0.5H2O) C,
H; N: calcd, 16.10; found, 15.21.
2-Ch lor o-5,11-d ih yd r o-11-eth yl-5-m eth yl-8-((2-tr iflu o-
r om eth yl-1-oxo-pyr idin -4-yl)oxy)m eth yl-6H-dipyr ido[3,2-
b:2′,3′-e][1,4]d ia zep in -6-on e (36). By a procedure analogous
to that used for the preparation of 32, and starting from XIXa
and 4-nitro-2-trifluoromethylpyridine N-oxide, compound 36
was produced in 36% yield: mp 105-108; 1H NMR 8.43 (d, J
) 2.4, 1H), 8.20 (d, J ) 7.3, 1H), 8.15 (d, J ) 2.4, 1H), 7.44 (d,
J ) 8.3, 1H), 7.25 (d, J ) 3.4, 1H), 7.12 (d, J ) 8.3, 1H), 7.00
(dd, J ) 7.3, 3.4, 1H), 5.08 (s, 2H), 4.19 (q, J ) 7.0, 2H), 3.48
(s, 3H), 1.27 (t, J ) 7.0, 3H); CIMS (CH4) 480 (MH+). Anal.
(C21H17ClF3N5O3) C, H, N.
2-Ch lor o-5,11-dih ydr o-11-eth yl-8-(2-m eth yl-4-pyr idin yl-
oxy)methyl-5-methyl-6H-dipyrido[3,2-b:2′,3′-e][1,4]diazepin-
6-on e (30). By a procedure analogous to that used for the
preparation of 32, and starting from XIXa and 4-nitro-2-
picoline, compound 30 was produced in 69% yield: mp 163-
164; 1H NMR 8.44 (d, J ) 2.4, 1H), 8.32 (d, J ) 5.8, 1H), 8.17
(d, J ) 2.4, 1H), 7.44 (d, J ) 8.3, 2H), 7.12 (d, J ) 8.3, 1H),
6.71 (d, J ) 2.3, 1H), 6.68 (dd, J ) 5.8, 2.3, 1H), 5.05 (s, 2H),
4.19 (q, J ) 7.0, 2H), 3.49 (s, 3H), 2.52 (s, 3H), 1.28 (t, J ) 7.0,
3H); CIMS (CH4) 410 (MH+). Anal. (C21H20ClN5O2‚0.25H2O)
C, H, N.
2.5, 1H), 8.45 (br s, 1H), 8.18 (d, J ) 2.5, 1H), 7.44 (d, J ) 8.3,
1H), 7.12 (d, J ) 8.3, 1H), 6.85 (d, J ) 6.2, 2H), 5.06 (s, 2H),
4.19 (q, J ) 7.0, 2H), 3.49 (s, 3H), 1.27 (t, J ) 7.0, 3H); CIMS
(CH4) 396 (MH+). Anal. (C20H18ClN5O2) C, H, N.
2-C h lo r o -5,11-d ih y d r o -11-e t h y l-5-m e t h y l-8-((2-t r i-
flu o r o m e t h y lp y r id in -4-y l)o x y )m e t h y l-6H -d ip y r id o -
[3,2-b:2′,3′-e][1,4]d ia zep in -6-on e (31). By a procedure analo-
gous to that used for the preparation of 27, and starting from
36, compound 31 was produced in 67% yield: mp 170-171;
1H NMR 8.55 (d, J ) 5.6, 1H), 8.46 (d, J ) 2.5, 1H), 8.18 (d, J
) 2.5, 1H), 7.45 (d, J ) 8.3, 1H), 7.24 (d, J ) 2.4, 1H), 7.12 (d,
J ) 8.3, 1H), 6.99 (dd, J ) 5.6, 2.4, 1H), 5.11 (s, 2H), 4.20 (q,
J ) 7.0, 2H), 3.49 (s, 3H), 1.28 (t, J ) 7.0, 3H); CIMS (CH4)
464 (MH+). Anal. (C21H17ClF3N5O2) C, H, N.
Meth od D. 2-Ch lor o-5,11-d ih yd r o-11-eth yl-5-m eth yl-
8-(N-m et h yl-N-p h en yl)ca r b oxa m id o-6H -d ip yr id o[3,2-b:
2′,3′-e][1,4]d ia zep in -6-on e (5). Compound XIXa (68 mg, 0.22
mmol) was dissolved in acetone (2.5 mL) and was treated with
J ones reagent (2.5M, 174 µL, 0.435 mmol). The reaction
mixture was stirred for 10 min. Then, 50% aqueous NaOH (2
mL) and saturated aqueous NaHCO3 (20 mL) were added, and
the mixture was extracted with CH2Cl2 (2 × 15 mL). The
aqueous phase was then acidified to pH ) 5 (1.2 M aqueous
HCl), extracted with EtOAc (3 × 20 mL), dried over Na2SO4,
and concentrated to give crude XXVI. The resulting residue
was dissolved in CH2Cl2 (10 mL) and treated with oxalyl
chloride (112 µL, 1.28 mmol) followed by a catalytic amount
of DMF (5 µL). After 15 min the solvent and excess oxalyl
chloride were removed in vacuo. The acid chloride was
redissolved in CH2Cl2 (9 mL) and treated with N-methylaniline
(47 µL, 0.43 mmol). After 15 min of stirring, the reaction
mixture was quenched with aqueous NaOH and extracted with
EtOAc (3 × 20 mL). The organic layer was dried over Na2-
SO4, and concentrated, and the residue was purified by flash
chromatography (1:1 hexanes/EtOAc to EtOAc gradient) fol-
lowed by recrystallization from hexanes to give 5 (59 mg,
1
65%): mp 165-167; H NMR 8.29 (d, J ) 2.1, 1H), 8.05 (d, J
) 2.1, 1H), 7.39 (d, J ) 8.3, 1H), 7.30-7.06 (m, 6H), 4.11 (q,
J ) 7.0, 2H), 3.48 (s, 3H), 3.41 (s, 3H), 1.18 (t, J ) 7.1, 3H);
CIMS (CH4) 422 (MH+). Anal. (C22H20ClN5O2) C, H, N.
2-Ch lor o-5,11-d ih ydr o-11-eth yl-5-m eth yl-8-(N-ben zen e-
ca r bon yl-N-m eth yla m in o-6H-d ip yr id o[3,2-b:2′,3′-e][1,4]-
d ia zep in -6-on e (6). To a cooled solution of XVII1a (41 mg,
0.13 mmol) in CH2Cl2 and N,N-diisopropylethylamine (35 µL,
0.2 mmol) was added benzoyl chloride (16 µL, 0.14 mmol). After
being warmed to ambient temperature, the mixture was
diluted with EtOAc and washed with H2O. The organics were
dried over MgSO4 and concentrated. The residue was dis-
solved in DMF (2 mL) and treated with NaH (8 mg, 0.17
mmol). After 15 min, MeI (12 µL, 0.19 mmol) was added. The
mixture was worked up by quenching with ice and extracting
with EtOAc. The organics were washed with brine, dried over
MgSO4, and concentrated. The residue was purified by column
chromatography (EtOAc/Hex) and recrystallization (EtOAc/
Hex) to afford 6 (24 mg, 43%): mp 166-169; 1H NMR 8.03 (d,
5,11-Dih ydr o-11-eth yl-5-m eth yl-8-(4-pyr idin yloxy)eth yl-
6H-d ip yr id o[3,2-b:2′,3′-e]-[1,4]d ia zep in -6-on e (27). A solu-
tion of 32 (72 mg, 0.190 mmol) in CHCl3 (5 mL) was treated
with PCl3 (24 µL, 0.28 mmol). After 3 h of stirring at ambient
temperature, the mixture was made alkaline with 15% aque-
ous NaOH and the organic layer was separated. The aqueous
layer was then extracted with CH2Cl2 (2 × 15 mL). The
combined organics were dried over Na2SO4, filtered, and
concentrated, and the residue was purified by preparative TLC
(10% MeOH/CH2Cl2) and further purified by precipitation from
EtOAc solution with hexanes to give 27 (57 mg, 83%): mp

Inhibitors of HIV-1 Reverse Transcriptase. 8
J ournal of Medicinal Chemistry, 1998, Vol. 41, No. 16 2983
J ) 2.7, 1H), 7.92 (d, J ) 2.7, 1H), 7.42 (d, J ) 8.2, 1H), 7.33-
7.19 (m, 5H), 7.12 (d, J ) 8.2, 1H), 4.09 (q, J ) 7.0, 2H), 3.46
(s, 3H), 3.45 (s, 3H), 1.19 (t, J ) 7.0, 3H); CIMS (CH4) 422
(MH+). Anal. (C22H20ClN5O2) C, H, N.
Ack n ow led gm en t. J ohn R. Proudfoot is gratefully
acknowledged for his development of the selective
bromination and ring closure conditions utilized in the
synthetic scheme leading to the synthesis of X. Helga
Silverstein, J oseph McDevitt, Bill Adams, and Peter
Kinkade are acknowledged for contributions to the in
vivo metabolism studies. J ohn L. Sullivan and Frank
Brewster of the University of Massachusetts are ac-
knowledged for performing the HIV-1 syncytia assay.
The authors thank Walter Davidson for performing the
HRMS analyses and Roger Dinallo for mass spectral
analysis of metabolites. J ohn Proudfoot, Leah Frye,
Daniel McNeil, and Karl Hargrave are acknowledged
for very helpful discussions and critical reading of the
manuscript. Additionally J ulian Adams, Usha Patel,
Suresh Kapadia, Terence Kelly, and Vittorio Farina are
acknowledged for their critical input as members of the
second generation NNRTI chemistry program.
Gen er a l Biologica l Meth od s. The procedures for the
reverse transcriptase wild-type and mutant enzyme, inhibition
of HIV-1IIIB replication in C8166 cells, and MTT toxicity assays
have appeared elsewhere.1b,4
In Vitr o Meta bolism Assa y. Male Sprague-Dawley rats
were obtained from either Taconic Farms (Germantown, NY,
strain Tac:N(SD)fBR). Human liver was received frozen (-80
°C) from the Department of Pharmacology and Toxicology of
the Medical College of Wisconsin (Milwaukee, WI) and was
collected according to their protocol from organ donors. The
tissue was stored frozen at -80 °C until the microsomes were
prepared.
P r ep a r a tion of Micr osom es. Animal and liver weights
were recorded. Subsequently, the livers were processed into
microsomes using a modification of the method of Guengerich.18b
Modifications included centrifugation at 145 000g at 4 °C for
60 min, rather than 100 000g and suspension of the mi-
crosomes for storage in 66 mM Tris buffer (pH 7.4, containing
250 mM sucrose and 5.4 mM EDTA). The microsomal suspen-
sions were stored in liquid nitrogen as 1 mL aliquots. Mi-
crosomal total protein concentration was determined by the
method of Lowry et al.,18c using bovine serum albumin as a
standard.
Refer en ces
(1) For previous papers in this series, see: (a) Klunder, J . M.;
Hoermann, M.; Cywin, C. L.; David, E.; Brickwood, J . R.;
Schwartz, R.; Barringer, K. J .; Pauletti, D.; Shih, C.-K.; Erickson,
D. A.; Sorge, C. L.; J oseph, D. P.; Hattox, S. E.; Adams, J .; Grob,
P. M. Novel Nonnucleoside Inhibitors of HIV-1 Reverse Tran-
scriptase. 7. 8-Arylethyldipyridodiazepinones as Potent Broad-
Spectrum Inhibitors of Wild-Type and Mutant Enzymes. J . Med.
Chem. 1998, 41, 2960-2971. (b) Kelly, T. A.; McNeil, D. W.; Rose,
J . M.; David, E.; Shih, C.-K.; Grob, P. M Novel Non-Nucleoside
Inhibitors of HIV-1 Reverse Transcriptase. 6. 2-Indol-3-yl and
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compound, 1 or 2 mg of microsomal protein (rat and human,
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nated by addition of 100 µL of 1 N aqueous NaOH. Test
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nitrogen at 40 °C. The dried residue was taken up into 200
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diode-array detector set to monitor UV absorbance between
200 and 400 nm and record a chromatogram at 240 nm. The
HPLC column was a Waters (Milford, MA) NovaPac C18 (300
× 3.9 mm) that was maintained at 40 °C in a column oven.
The flow rate was 1.0 mL/min with an isocratic mobile phase
of 17/83 acetonitrile/0.05 M phosphate buffer (pH 4.6) contain-
ing 0.1% triethylamine (v/v). Test compounds and their
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In Vivo Ra t Meta bolism . Five male rats were fasted for
12-16 h prior to oral or intravenous administrations of test
compounds. Two animals received test compound via in-
tavenous injection in a 1.0 mg/mL solution (30% DMA, 0.9%
NaCl in H2O) at 1.0 mg/kg. Three animals received test
compounds by gavage as 0.5 mg/mL suspensions (0.5% Me-
thocel, 0.3% Tween 80) at 5 mg/kg. Blood samples were
obtained from interdwelling jugular cannulas at 0.08 (iv
treatment only), 0.25, 0.5, 1, 1.5, 2, 3, 4, 6, 8, 24 h after dosing.
Plasma was recovered and frozen (-20 °C) until analysis.
Assa y P r oced u r e. Plasma samples (400 µL) were alka-
linized with 50 µL of 3.3 N NaOH and were shaken for 20 min
with 5 mL of EtOAc. The EtOAc extracts were transferred to
16 × 100 mm glass tubes and evaporated to dryness under N2
at 45 °C. The residues were dissolved in 200 µL of 40 mM
KH2PO4, pH 4.5:AcCN (68:32) and centrifuged at 14 000g.
Aliquots (100 µL) of the supernatants were injected onto the
following HPLC system: column, C18 MetaChem Intersil 5 µ
cm, 4.6 × 150 mm; mobile phase, 40 mM KH2PO4, pH 4.5:
AcCN (68:32); flow rate, 1.2 mL/min; column temp, 40 °C;
detector, UV set to monitor 236 nm. Test compounds and their
metabolites were quantitated with calibration curves that were
constructed using authentic standards.

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J M9707030