Design, synthesis, and evaluation of 3,4-dihydro-2H-[1,4]diazepino[6,7,1- hi]indol-1-ones as inhibitors of poly(ADP-ribose) polymerase

Article abstract of DOI:10.1021/jm030513r

The design, synthesis, and biological evaluation of potent inhibitors of poly(ADP-ribose) polymerase-1 (PARP-1) are reported. A novel series of 3,4-dihydro-2H-[1,4]diazepino[6,7,1-hi]indol-1-ones were designed using a combination of protein structure-base

Full text of DOI:10.1021/jm030513r

J . Med. Chem. 2004, 47, 5467-5481
5467
Design , Syn th esis, a n d Eva lu a tion of
3,4-Dih yd r o-2H-[1,4]d ia zep in o[6,7,1-h i]in d ol-1-on es a s In h ibitor s of
P oly(ADP -Ribose) P olym er a se
J ayashree G. Tikhe,*,† Stephen E. Webber,‡ Zdenek Hostomsky,† Karen A. Maegley,† Anne Ekkers,† J ianke Li,†
Xiao-Hong Yu,† Robert J . Almassy,§ Robert A. Kumpf,† Theodore J . Boritzki,† Cathy Zhang,† Chris R. Calabrese,|
Nicola J . Curtin,| Suzanne Kyle,| Huw D. Thomas,| Lan-Zhen Wang,| A. Hilary Calvert,| Bernard T. Golding,|
Roger J . Griffin,| and David R. Newell|
Pfizer Global R&DsLa J olla Laboratories, 10770 Science Center Drive, San Diego, California 92121,
Anadys Pharmaceuticals, 3115 Merryfield Row, San Diego, California 92121, Quorex Pharmaceuticals,
1890 Rutherford Road, #200, Carlsbad, California 92008, and University of Newcastle,
Newcastle upon Tyne NE2 4HH, United Kingdom
Received October 10, 2003
The design, synthesis, and biological evaluation of potent inhibitors of poly(ADP-ribose)
polymerase-1 (PARP-1) are reported. A novel series of 3,4-dihydro-2H-[1,4]diazepino[6,7,1-hi]-
indol-1-ones were designed using a combination of protein structure-based drug design,
molecular modeling, and structure-activity relationships (SAR). These novel submicromolar
inhibitors possess a tricyclic ring system conformationally restricting the benzamide in the
preferred cis orientation. The compounds were designed to optimize space-filling and atomic
interactions within the NAD+ binding site of PARP-1. Previously described and newly adapted
methods were applied to syntheses of these tricyclic inhibitors. Various modifications were
made to the diazepinoindolones at the 6- and 7-positions in order to study this region of the
active site and optimize noncovalent interactions. The electron density of derivative 28 bound
to chicken PARP-1 revealed that the oxime makes a tight hydrogen bond with the catalytic
γ-carboxylate of glutamic acid (Glu) 988 in accordance with our original designs and models.
Most of the compounds have been evaluated for inhibition of human PARP-1. Selected inhibitors
were also tested for the ability to potentiate the cytotoxic effect of the DNA-damaging agent
Topotecan.
In tr od u ction
many PARP inhibitors potentiate the effects of ionizing
radiation or cytotoxic agents and, therefore, may serve
as effective adjunct cancer chemotherapeutics.15-20
PARP-1 has also been implicated in several other
disease states. In addition to anticancer therapies,
inhibitors may have utility against myocardial infarc-
tion, neurotoxicity consequent to stroke, head trauma,
neurodegenerative diseases, insulin-dependent diabetes
mellitus, and arthritis and inflammation.10,21-25
Many PARP inhibitors, designed as nicotinamide
mimics, have been reported. Representative examples
are shown in Figure 1. 3-Aminobenzamide, I, has been
widely used in numerous studies; however, this simple
compound lacks the potency and efficacy required to
make it therapeutically useful.26,27 Second-generation
nicotinamide-based molecules made use of tetrahydro-
isoquinolin-2-one to restrict the amide in its cis confor-
mation. PD128763, II, was shown to be approximately
50-fold more active than 3-aminobenzamide; however,
development of this compound was discontinued.15,28
Other constricted carboxamide-like examples include
imides such as III27 and quinazolinones such as IV.17
More recently, a class of potent benzimidazole PARP
inhibitors, V, was developed at the University of New-
castle.29 The requisite cis amide geometry is locked in
place through an eloquent design of an intramolecular
hydrogen bond between the -NH2 and the lone pair
electrons of N-3.
Poly(ADP-ribose) polymerases (PARPs), nuclear en-
zymes found in almost all eukaryotic cells, catalyze the
transfer of ADP-ribose units from nicotinamide adenine
dinucleotide (NAD+) to nuclear acceptor proteins and
are responsible for the formation of protein-bound linear
and branched homo-ADP-ribose polymers.1-8 The acti-
vation of PARP and the formation of poly(ADP-ribose)
are the result of DNA strand breaks induced from
exposure to certain chemotherapeutics, ionizing radia-
tion, oxygen free radicals, or nitric oxide.9,10 The accep-
tor proteins of poly(ADP-ribose), including histones,
topoisomerases, DNA and RNA polymerases, DNA
ligases, and metal-dependent endonucleases, are in-
volved in maintaining DNA integrity.7,11-14
The cellular ADP-ribose transfer process may “indi-
rectly” contribute to the resistance that often develops
to various types of cancer therapies through its role in
repairing DNA strand breaks caused by radiotherapy
or chemotherapy. Consequently, inhibition of PARP-1
(EC 2.4.2.30), the most abundant form of the PARPs,
may retard intracellular DNA repair and thereby en-
hance and prolong the antitumor effects of certain
anticancer therapies. In vitro and in vivo data show that
* To whom correspondence should be addressed. Tel: 858-622-3172.
Fax: 858-678-8156. E-mail: jayashree.tikhe@pfizer.com.
† Pfizer Global R&DsLa J olla Laboratories.
‡ Anadys Pharmaceuticals.
Our group has recently reported three novel classes
§ Quorex Pharmaceuticals.
| University of Newcastle.
of tricyclic PARP-1 inhibitors, shown in Figure 2.20,30,31
10.1021/jm030513r CCC: $27.50 © 2004 American Chemical Society
Published on Web 09/29/2004

5468 J ournal of Medicinal Chemistry, 2004, Vol. 47, No. 22
Tikhe et al.
F igu r e 4.
F igu r e 1.
F igu r e 2.
F igu r e 3.
Models of structure IX in the PARP-1 active site also
show C-7 to be in close proximity to the catalytically
relevant γ-carboxylic acid of Glu-988. Glu-988 functions
in the polymerization reaction by forming a crucial
hydrogen bond with the 2′-hydroxyl of the growing poly-
(ADP-ribose) chain, thus activating this hydroxyl for
nucleophilic attack of carbon in the nicotinamide-ribose
bond of the donor NAD+ molecule.32-34 In addition to
activation, the hydrogen bond to the donor ribose
hydroxyl stabilizes an oxocarbenium-like transition
state.34-36
From crystallographic data, a water molecule is often
observed situated between the nitrogen atom of the
inhibitor and the γ-carboxylate of Glu-988, forming
hydrogen bonds that “bridge” the ligand to the en-
zyme.30,31 Figure 4 illustrates a schematic depiction of
crystallographically observed atomic interactions be-
tween inhibitors of type VII and the active site residues
of chicken PARP-1.30
We became very interested in the design of inhibitors
that would possibly interact directly with Glu-988.
Other research groups have also explored this region
of the active site. Through crystallographic studies, Ruf
et al. provided evidence that the 4-amino group of III
forms a hydrogen bond with the γ-carboxylate of Glu-
988.37 Watson et al. designed electrophilic benzamide
and isoquinolinone derivatives in an attempt to test
whether Glu-988 would act as a nucleophile to form a
covalent bond in a mechanism-based fashion.38
Our initial molecular modeling and design indicated
that H2O-52 could be displaced by other hydrogen bond
donors, in particular the NOH of an E-carboxaldehyde
oxime. A number of C-7-substituted diazepinoindolones
were designed and prepared in order to determine
whether direct interactions to Glu-988 would enhance
inhibition of PARP-1 and to test the limitations of H2O-
52 displacement or reorientation.
From our previous studies, we also learned that aryl
groups at C-2 of tricylic compounds VII and VIII were
advantageous to binding.30,31 Aryl rings occupy hydro-
phobic space in this region of the active site, predomi-
nantly interacting with the side chains of Tyr-889 and
Tyr-896. Capitalizing on the structure-activity rela-
tionship (SAR) information learned from the published
series, several 6-substituted diazepinoindolones were
The conception of these unique tricyclic inhibitors was
based on the combination of reported information and
protein-ligand structure-based design. As a continua-
tion of our research, we have expanded this series to
include 3,4-dihydro-2H-[1,4]diazepino[6,7,1-hi]indol-1-
ones.
Molecu la r Design
In preceding publications, our group has described the
design and syntheses of tricyclic PARP-1 inhibitors.30,31
Incorporation of the seven-membered ring in VII and
VIII not only locks the critical amide in the required
cis geometry but also better disrupts the planarity of
the tricyclic core, thereby filling more hydrophobic space
while conceivably enhancing the overall physical prop-
erties of the molecule. Close examination of cocrystal
structures of chicken PARP-1 complexed with inhibitors
of type V or VII revealed a region adjacent to N-1
accessible for further modification.29,30 It was previously
shown that N-1 methylation of 2-phenyl-1,3,4,5-tetrahy-
droazepino[5,4,3-cd]indol-6-one (VIIa ) is well-tolerated
and not detrimental to binding.30 We envisaged the
tricyclic 3,4-dihydro-2H-[1,4]diazepino[6,7,1-hi]indol-1-
one IX (Figure 3) to be an attractive alternative scaffold
since synthetic modifications at C-7 would allow us to
readily probe this scantily explored region of the active
site.

3,4-Dihydro-2H-[1,4]diazepino[6,7,1-hi]indol-1-ones
J ournal of Medicinal Chemistry, 2004, Vol. 47, No. 22 5469
Sch em e 1. Synthesis of 7-Methyl-3,4-dihydro-2H-[1,4]diazepino[6,7,1-hi]indol-1-ones (Method A)a
a
Conditions and reagents: (a) DDQ, Ph-H. (b) ex POCl3, DMF. (c) NaBH4, EtOH. (d) AcOAc, pyr, DMAP. (e) 10% Pd/C, H2, AcOH,
MeOH. (f) I2, (CF3CO2)2IC6H5, CH2Cl2. (g) R2-B(OH)2, catalytic (Ph3P)4Pd, LiCl, Na2CO3, DMF, H2O.
Sch em e 2. Synthesis of 6-Substituted 3,4-Dihydro-2H-[1,4]diazepino[6,7,1-hi]indol-1-ones (Method B)a
a
Conditions and reagents: (a) â-Propiolactone, CH3CN, reflux. (b) P2O5, CH3SO3H, room temperature-65 °C. (c) NaN3, CH3SO3H. (d)
R2-≡-H, catalytic (Ph3P)4Pd, CuI, Et2NH, DMF. (e) Catalytic PdCl2, CH3CN, 60-70 °C.
therefore prepared and tested. The meta- and para-
substituted N-alkylaminomethyl and N,N-dialkylamino-
methyl phenyl analogues were designed with the pri-
mary intent to improve the aqueous solubility of the
compounds. These substituents were previously ex-
ploited in tricyclic series VI-VIII.30,31 The aminometh-
ylene groups are generally well-accommodated in the
enzyme active site. Molecular modeling of these func-
tional groups and crystallographic data for a related
inhibitor31 suggest that the positively charged amino
group participates in favorable electrostatic interactions
to the side chains of Gln-763,39 Asp-766, and Tyr-896.
Finally, we were curious to learn whether 6,7-disub-
stituted derivatives would have additive effects on
PARP inhibition. The 3,4-dihydro-2H-[1,4]diazepino-
[6,7,1-hi]indol-1-one tricycle is an ideal ring system that
readily allowed us to concurrently access both active site
regions of interest via disubstitutions at the 6- and
7-positions.
preparation of 7-methyl-3,4-dihydro-2H-[1,4]diazepino-
[6,7,1-hi]indol-1-one 5 by the catalytic deoxygenation of
the acetate of 4. Iodide 6, generated in moderate yield
from 5, was used as a common intermediate in Suzuki
type41 palladium-catalyzed coupling of arylboronic acids
to prepare the 6-aryl-7-methyl analogues 7-9 listed in
Table 3.
Achieving monosubstitution at C-6 and disubstitution
at C-6 and C-7 with greater diversity turned out not to
be very convenient using 2 as a starting material.
Because of synthetic limitations, an alternative synthe-
sis of 3,4-dihydro-2H-[1,4]diazepino[6,7,1-hi]indol-1-ones
was investigated as outlined in Scheme 2 (method B).
Our new strategy relied on indole ring formation in the
final step of the construction of the tricyclic core.
Starting from 2-iodoaniline, compound 10 was prepared
following a literature procedure.42 In the same report,
however, the authors were unsuccessful in their at-
tempts to convert 10 to 8-iodo-tetrahydro-quinolin-4-one
11 using polyphosphoric acid and only observed position
scrambling of iodine and dehalogenation during cycliza-
tion.42 We were able to circumvent this problem and
thus transform 10 to 11 in good yields when Eaton’s
reagent (P2O5/CH3SO3H)43 was used. Ring expansion
under Schmidt44 reaction conditions gave iodo-diazepi-
none 12 in very good yield. Intermediate 12 was then
subjected to tandem palladium-catalyzed acetylene
coupling and indole cyclization to afford the tricyclic
lactams 14-19.45,46 This new route also proved to be a
more efficient method to prepare compound 2. The 6-
Ch em istr y
We initially considered the unsubstituted 3,4-dihydro-
2H-[1,4]diazepino[6,7,1-hi]indol-1-one 2 to be a versatile
intermediate. It was synthesized from 1 using reported
procedures.40 Formylation or iodination via electrophilic
aromatic substitution of 2 at C-7 allowed for the
preparation of several derivatives as shown in Schemes
1 and 3. Scheme 1 (method A) depicts the syntheses of
key intermediates 2 and 3 and further describes the

5470 J ournal of Medicinal Chemistry, 2004, Vol. 47, No. 22
Tikhe et al.
Sch em e 3. Synthetic Modifications to the 7-Position of 3,4-Dihydro-2H-[1,4]diazepino[6,7,1-hi]indol-1-onesa
a
Conditions and reagents: (a) I2, DMF, KOH. (b) CO, Et3N, catalytic (Ph3P)2PdCl2, DMF, MeOH. (c) NH2OH‚HCl, H2O, NaOH, EtOH.
(d) NH2OMe-HCl, pyr., EtOH. (e) RLi, THF. (f) o-Iodooxybenzoic acid, DMSO. (g) NH2OH‚HCl, pyr.
Ta ble 1. 7-Substituted
substituted 3,4-dihydro-2H-[1,4]diazepino[6,7,1-hi]indol-
3,4-Dihydro-2H-[1,4]diazepino[6,7,1-hi]indol-1-ones
1-ones prepared are listed in Table 2.
The syntheses of 7-substituted derivatives via the
highly versatile 7-formyl or 7-iodo intermediates 3 and
26, respectively, are described in Scheme 3. Intermedi-
ate 3 was directly converted to oximes 28-30, while a
three-step sequence was used to synthesize keto-oximes
33 and 36. Table 1 lists all 7-substituted diazopino-
Ki
indolones synthesized.
no.
R1
mp (°C)
formulaa
(nM)b,c
Next, we focused our efforts on the synthesis of 6,7-
disubstituted 3,4-dihydro-2H-[1,4]diazepino[6,7,1-hi]-
indol-1-ones. Schemes 4 and 5 describe the synthesis of
6,7-disubstituted compounds with functional groups at
the C-7 other than methyl and capable of displacing or
hydrogen bonding to H2O-52. As shown in Scheme 4,
oximes 38 and 40 were readily prepared from aldehydes
37 and 39, respectively. Oxime 40 was dehydrated with
thiocarbonyldiimidazole to give nitrile 41, a common
intermediate used to prepare amide 42 and thioamide
43. The methyl thiouronium salt 44 was readily pre-
pared from 43 and further converted to N-hydroxy-
amidine 45 with hydroxylamine or N-aminoamidine 46
with hydrazine. Scheme 5 describes the synthesis of
7-acetyl-diazepinoindolone 48 from the corresponding
iodide 47. Acetyl 48 is used to prepare keto-oxime 49
and pyrrazole 51. The data for the 6,7-disubstituted 3,4-
dihydro-2H-[1,4]diazepino[6,7,1-hi]indol-1-ones prepared
are listed in Table 3.
2
3
4
5
H
165-167
238-240
C
C
11H10N2O‚0.05H2O
12H10N2O2‚0.1H2O
105
176
79
122
304
CHO
CH2OH
CH3
I
180-182 C12H12N2O2‚0.20H2O
135-137
188-190
259-261
262-264
173-175
210-212
295-297
285-287
C
C
C
C
C
C
C
C
12H12N2O
26
11H9N2OIa
27 COOCH3
13H12N2O3‚0.25H2O 900
12H11N3O2
28 CHdNOH
29 (E)-CHdNOMe
30 (Z)-CHdNOMe
31 CH(OH)CH3
32 COCH3
33 C(CH3)dNOH
34 C(OH)C6H5
35 COC6H5
9.4
13H13N3O2‚0.25H2O 809
13H13N3O2‚0.1H2Oa 121
13H14N2O2
13H12N2O2
692
606
39
238-240 C13H13N3O2
178-180
229-230
263-265
C
C
C
18H16N2O2‚0.25H2O 380
18H14N2O2
18H15N3O2‚0.1H2O
337
38
36 (E) and (Z)-
C(C6H5)dNOH
a
Compounds were analyzed for C, H, and N; the results are in
agreement to within (0.4% of the theoretical values except for
26: C, calcd, 42.33; found, 42.81. Compound 30: analysis passed
only with 0.1EtOAc. Human PARP-1 enzyme inhibition; values
b
are an average of at least two independent experiments; % error
e (20%. c See Experimental Section for conditions.
The last sets of compounds, meta- and para-arylamino-
methylene derivatives 20-25, were derived under re-
ductive amination conditions of the appropriate alde-
hyde. As exemplified in Scheme 6, the meta-dimethyl-
aminomethylene analogue 20 was prepared using method
C. This route was developed and chosen over method B
since it provided a more convenient and higher yielding
synthesis of the penultimate aldehydes from common
intermediate 53 and commercially available iodo-
benzaldehydes.
En zym e In h ibition a n d Cr ysta llogr a p h ic An a ly-
sis. Data for the synthesized diazepinoindolinones are
reported in Tables 1-3. Enzyme inhibition constants
were determined using a previously reported method
as described in the Experimental Section.30,31,33 Oxime

3,4-Dihydro-2H-[1,4]diazepino[6,7,1-hi]indol-1-ones
J ournal of Medicinal Chemistry, 2004, Vol. 47, No. 22 5471
Sch em e 4. Synthesis of 6,7-Disubstituted 3,4-Dihydro-2H-[1,4]diazepino[6,7,1-hi]indol-1-onesa
a
Conditions and reagents: (a) ex POCl3, DMF. (b) NH2OH‚HCl, pyr. (c) Thiocarbonyldiimidazole, THF. (d) 85% H3PO4, 90-100 °C. (e)
H2S, pyr., Et3N, 0 °C. (f) CH3I, THF. (g) NH2NH2, CH3CN, then HCl/MeOH.
Sch em e 5. Synthesis of 6,7-Disubstituted 3,4-Dihydro-2H-[1,4]diazepino[6,7,1-hi]indol-1-onesa
a
Conditions and reagents: (a) I2, DMF, KOH. (b) H2CdC(OEt)SnBu3, (Ph3P)4Pd, 2,6-di-tBu-4-Me-phenol, 1,4-dioxane, DMF. (c)
NH2OH‚HCl, pyr. (d) (CH3)2NCH(OCH3)2, DMF, 110-120 °C. (e) NH2NH2‚H2O, THF.
derivatives were the best enzyme inhibitors of all of the
C-7 monosubstituted diazapinoindolinones (Table 1).
The simplest trans-oxime, compound 28, a 9.8 nM
inhibitor of PARP-1, was the most potent derivative in
this series with a Ki value 11 times lower than the
parent compound 2.
Compound 28 was cocrystallized with the C-terminal
catalytic domain of chicken PARP-1 protein, and a 2.8
Å structure was solved (Figures 5 and 6). As anticipated
from previous studies, the tricyclic core is wedged
between the side chains of Tyr-896 and Tyr-907, while
three key hydrogen bonds between the ligand amide and
the protein are made.30,31 The C-1 lactam carbonyl forms
two hydrogen bonds, one to the side chain hydroxyl of
Ser-904 and the other to the backbone amide of Gly-
863. The N-2 lactam NH hydrogen bonds to the back-
bone carbonyl of Gly-863. The three-dimensional struc-
ture also confirmed our modeling. The E-oxime displaced
a water molecule, and the -OH formed a very tight
H-bond to the catalytic γ-carboxylic acid of Glu-988.
The important role this interaction has on binding
was confirmed by the loss of affinity upon O-methylation
of the oxime group. The corresponding trans-O-methyl
analogue 29 has a Ki value 86 times greater than 2,
whereas the cis-O-methyl oxime 30 has a Ki about 13
times higher. Models of either 29 or 30 into the
crystallographic complex of 28 and PARP-1 suggest that
neither compound can be situated in the active site as
well as 28, especially since the O-methyl group prevents
a direct interaction to Glu-988.
Oximes 33 and 36, derived from methyl ketone 32 and
phenyl ketone 35, respectively, have Ki values four times

5472 J ournal of Medicinal Chemistry, 2004, Vol. 47, No. 22
Tikhe et al.
Sch em e 6. Synthesis of 6-[3-(CH2NMe2)phenyl]-3,4-dihydro-2H-[1,4]diazepino[6,7,1-hi]indol-1-ones (Method C)a
a
Conditions and reagents: (a) Trimethylsilylacetylene, catalytic (Ph3P)4Pd, CuI, Et2NH, DMF. (b) Catalytic K2CO3, MeOH. (c)
4-Iodobenzaldehyde, catalytic (Ph3P)4Pd, CuI, Et2NH, DMF. (d) PdCl2, CH3CN, 70-80 °C. (e) HN(CH3)2, MeOH, NaBH3CN, HCl, H2O.
F igu r e 5. Electron density for compound 28 bound to chicken
PARP-1. The initial 2.8 Å 2Fo-Fc electron density contoured
at 1σ and phased with the PARP-1 protein and solvent model
from a previous cocrystal structure.29
greater than 28. Models of both compounds into the
cocrystal structure suggest that there is inadequate
F igu r e 6. X-ray structure complex of 28 and chicken PARP-1
space in the active site to accommodate either the
methyl or the phenyl substituents, forcing the tricyclic
ring to shift, thereby perturbing the optimal binding
orientation observed with 28. Hydroxymethyl derivative
4 was the only compound other than the oximes with a
Ki value less than parent compound 2.
Next, we focused our attention on C-6 monosubsti-
tuted diazepinoindolinones. As expected, the addition
of various aryl groups at C-6 markedly enhances
PARP-1 inhibition. Previous studies also established
that potency could be enhanced with meta- or para-
aminomethylene groups while improving aqueous solu-
bility.30,31 In general, para-aminomethylene derivatives
23-25 were indeed three of the most potent enzyme
inhibitors prepared. The inhibition data for the C-6
monosubstituted diazepinoindolinones are listed in
Table 2.
highlighting key protein residues and hydrogen bonds. Or-
dered water molecules are represented as red crosses, and the
solvent-exposed surface of the PARP-1 active site is drawn
with white dots.
hibitor of PARP-1 reported by Canan Koch et al.30
However, when comparing their inhibitory activities
against PARP-1, 7 has a Ki value of 41 nM, ap-
proximately six times higher than VIIa . Modeling
results imply that the reduction in potency may be due,
at least in part, to the loss of a weak hydrogen bond to
Tyr-907 (CH3N- - -H-O) and a less favorable electro-
static interaction with the aromatic ring of Tyr-907.
We postulated that a 6,7-disubstituted diazepino-
indolone combining the carboxaldeoxime of 28 and the
4-fluorophenyl of 17 might provide a significant boost
in activity against PARP-1. Analogue 40 is a 6.0 nM
inhibitor of PARP-1, only marginally better than either
28 or 17. Of interest is the 6,7-disubstituted diazepino-
indolone analogue 49, a combination of the methyl keto-
oxime of 33 and the 4-fluorophenyl of 17. Compound
49, a 9.1 nM enzyme inhibitor, has a Ki about four times
less than 33, but when compared to 17, 28, or 40, the
Examples of 6,7-disubstituted diazepinoindolones are
shown in Table 3. Compound 7, 7-methyl-6-phenyl-3,4-
dihydro-2H-[1,4]diazepino[6,7,1-hi]indol-1-one, is closely
related structurally to N-1-methyl-2-phenyl-1,3,4,5-tetra-
hydroazepino[5,4,3-cd]indol-6-one (VIIa ), a 7 nM in-

3,4-Dihydro-2H-[1,4]diazepino[6,7,1-hi]indol-1-ones
J ournal of Medicinal Chemistry, 2004, Vol. 47, No. 22 5473
Ta ble 2. 6-Substituted
3,4-Dihydro-2H-[1,4]diazepino[6,7,1-hi]indol-1-ones
their possible use as resistance-modifying agents, se-
lected 3,4-dihydro-2H-[1,4]diazepino[6,7,1-hi]indol-1-one
PARP-1 inhibitors were evaluated for potentiation of
topoisomerase I inhibitor TP cytotoxicity against human
lung carcinoma A549 cells. Alone, diazepinoindolone
PARP-1 inhibitors did not inhibit A549 cell growth at
400 nM, the standard concentration selected to inves-
tigate the potentiation of TP. This concentration is well
below the IC50 values of those compounds tested, except
for compound 40, where the single agent IC50 was less
than twice the standard concentration used in the
potentiation assay. The potentiation factor is reported
as a PF50. PARP-1 inhibitors with a PF50 value >1
increase the growth inhibitory effects of TP to that
degree, while inhibitors with values ) 1 have no
effect.30,31 As learned from previous studies, a correla-
tion between the Ki and the PF50 value does not exist;
however, low nanomolar inhibition of PARP-1 is un-
doubtedly required for potentiation. Of the inhibitors
tested, compound 23 provided the best enhancement,
reducing the IC50 of TP by a factor of 1.9. The data are
listed in Table 4.
In summary, 3,4-dihydro-2H-[1,4]diazepino[6,7,1-hi]-
indol-1-ones (IX), a third generation of novel 5,6,7-
tricyclic PARP-1 inhibitors with structural homology to
the 3,4,5,6-tetrahydro-1H-azepino[5,4,3-cd]indol-6-ones
(VII) and 8,9-dihydro-7H-2,7,9a-triaza-benzo[cd]azulen-
6-ones (VIII), were designed with the aid of protein
structure-based drug design, molecular modeling, and
SAR. An efficient synthesis was developed to prepare
various C-7-substituted molecules that allowed us to
study additional intermolecular interactions within the
catalytic site, particularly with Glu-988. The C-7 car-
boxaldeoxime derivatives are some of the most potent
PARP-1 inhibitors reported to date. The cocrystal
structure of compound 28 bound to the PARP-1 vali-
dated our design process. The combination of an oxime
Ki
R2
mp (°C)
formulaa
(nM)b,c
14 C6H5
15 4-Cl-C6H4
16 4-MeO-C6H4
17 4-F-C6H4
18 (CH2)2C6H4
19 2-pyridyl
20 3-[CH2N(CH3)2]-C6H4
21 3-[CH2NHCH3]-C6H4
22 3-[CH2N-pyrrolyl]-C6H4 158-160
23 4-[CH2N(CH3)2]-C6H4
24 4-[CH2NHCH3]-C6H4
165-167
238-240
188-190
198-200
188-190
185-187
98-100
C
C
C
C
C
C
C
C
C
C
C
C
C
17H14N2O‚0.1H2O
17H13N2OCl
18H16N2O2‚0.1H2O
17H13N2OF
14.3
11
8.2
11
27
68
9.1
6.9
12.5
6.4
3.8
6.8
ND
19H18N2O
16H13N3O‚0.8H2O
20H21N3O‚0.25H2O
19H19N3O‚0.6H2O
22H23N3O‚0.4H2O
20H21N3O‚0.3H2O
19H19N3O‚0.1H2O
22H23N3O‚0.25H2O
18H14N2O2‚0.25H2O
128-130
140-142
178-180
25 4-[CH2N-pyrrolyl]-C6H4 146-148
55 3-CHO-C6H4
192-194
a
Compounds were analyzed for C, H, and N; the results are in
b
agreement to within (0.4% of the theoretical values. Human
PARP-1 enzyme inhibition; values are an average of at least two
independent experiments; % error e (20%. c See Experimental
Section for conditions.
Ki values are relatively equal. Other 6-aryl-diazepino-
indolones with various functional groups at the 7-posi-
tion capable of forming H-bonds directly to Glu-988, or
via the mobile bridging water molecule, were investi-
gated. None of these, including amide 42, N-hydroxy-
amidine 45, and N-aminoamidine 46, showed enhanced
binding to PARP-1 when compared to oximes 38, 40,
and 49 or to the simpler 6-aryl- or 7-carboxaldeoxime
monosubstituted diazepinoindolones.
In Vitr o Cellu la r Gr ow th In h ibition ; En h a n ce-
m en t of Top oteca n (TP ) Cytotoxicity. To evaluate
Ta ble 3. 6,7-Disubstituted 3,4-Dihydro-2H-[1,4]diazepino[6,7,1-hi]indol-1-ones
Ki
no.
R1
R2
C6H5
mp (°C)
formulaa
(nM)b,c
7
8
9
CH3
CH3
CH3
CHO
278-280
270-272
258-260
278-279
249-251
268-270
277-279
248-250
287-289
238-240
257-259
272-274
283-285
275-276
248-250
173-175
C
C
C
C
C
C
C
C
C
C
C
C
C
C
C
C
18H16N2O‚0.4H2O
18H15N2OF‚0.1H2O
41
22
79
4-F-C6H4
3-CF3-C6H4
4-Cl-C6H4
4-Cl-C6H4
4-F-C6H4
4-F-C6H4
4-F-C6H4
4-F-C6H4
4-F-C6H4
4-F-C6H4
4-F-C6H4
4-F-C6H4
4-F-C6H4
4-F-C6H4
4-F-C6H4
d
19H15N2OF3
37
38
39
40
41
42
43
45
46
47
48
49
51
18H13N2O2Cl‚0.25H2O
43
CHdNOH
CHO
CHdNOH
CN
CONH2
CSNH2
CHdNOHNH2
CHdNHNHNH2
I
COCH3
C(CH3)dNOH
2-pyrazolyl
18H14N3O2Cla
7.5
ND
6
18H13N2O2Fe
18H14N3O2F‚0.3H2Oa
18H12N3OF‚0.1H2O
18H14N3O2F‚0.5H2O
18H14N3OSF‚0.4H2O
18H15N4O2F‚0.5H2O
18H16N5OF‚1H2Oa
17H12NOIF
54
200
219
87
57
ND
306
9.1
249
19H15N2O2Ff
19H16N3O2F‚0.1H2O
20H15N4OFa
a
Compounds were analyzed for C, H, and N; the results are in agreement to within (0.4% of the theoretical values except for 38:
analysis passed only with 0.75CH2Cl2. Compound 40: N, calcd, 12.78; found, 12.32. Compound 46: analysis passed only with 4.5HCl.
b
Compound 51: analysis passed only with 1.0MeOH. Human PARP-1 enzyme inhibition; values are an average of at least two independent
experiments; % error e (20%. c See Experimental Section for method. 90% pure by HPLC. e 99% pure by HPLC. f 98% pure by HPLC.
d

5474 J ournal of Medicinal Chemistry, 2004, Vol. 47, No. 22
Tikhe et al.
Ta ble 4. Potentiation of TP-Induced Growth Inhibition by
6,7-Disubstituted 3,4-Dihydro-2H-
[1,4]diazepino[6,7,1-hi]indol-1-ones in A549 Cells
NH4OAc, 10% CH3CN up to 2 min, then reaching 100% CH3CN
after 22 min, was used. Flow rate ) 25 mL/min. Flash column
chromatography was performed using silica gel 60 (Merck Art
9385). Thin layer chromatographs were performed on pre-
coated sheets of silica 60 F254 (Merck Art 5719). Melting points
were determined on a Mel-Temp apparatus and are uncor-
rected. All commercial solvents were reagent grade or better
and used as supplied. All reactions were performed in septum-
sealed flasks under a slight positive pressure of argon, unless
otherwise noted.
P ARP En zym e In h ibition Assa y. The PARP enzyme-
inhibiting activities of the compounds were assayed as de-
scribed by Simonin et al.47 and Marsischky et al.33 with minor
modifications as follows. Samples (50 µL) containing 20 nM
purified PARP protein, 10 µg/mL DNAse I-activated calf
thymus DNA (sigma), 500 µM NAD+, 0.5 µCi [32P]NAD+, 2%
DMSO, and various concentrations of test compounds were
incubated in sample buffer [50 mM Tris, pH 8.0, 10 mM MgCl2,
and 1 mM tris(carboxyethyl)phosphine HCl] at 25 °C for 4 min.
Under these conditions, the reaction rate was linear up to 10
min. The reaction was stopped by the addition of an equal
volume of ice-cold 40% trichloroacetic acid. The samples were
then incubated on ice for 15 min, transferred to a Bio-Dot
microfiltration apparatus (Biorad), and filtered through What-
man GF/C glass-fiber filter paper. Filters were washed three
times with 150 µL of wash buffer (5% trichloroacetic acid and
1% inorganic pyrophosphate) and dried. [32P]ADP-ribose in-
corporation into the acid insoluble material was quantified
using a PhosphorImager (Molecular Dynamics) and Image-
Quant software. Inhibition constants (Ki) were calculated by
nonlinear regression analyses using the velocity equation for
competitive inhibition.48 In the case of tight-binding inhibitors,
5 nM enzyme was used and the reaction was incubated at 25
°C for 15 min. Ki values for tight-binding inhibitors were
calculated using the equation described by Sculley et al.49
IC50
(alone) (+TP)
(nM)a (nM)b (nM)c PF50
IC50
Ki
d
no.
R1
R2
8
CH3
H
4-F-C6H4
22
11
11
6000
3000
8000
21.8
13.3
13.3
15.0
12.6
18.5
20.0
1.1
1.8
1.8
1.6
1.9
1.3
1.2
15
17
20
23
4-Cl-C6H4
H
H
H
4-F-C6H4
3-[CH2N(CH3)2]C6H4
4-[CH2N(CH3)2]C6H4
H
9.1 11000
6.4
9.4
6
7000
8000
<800
24
28 CHdNOH
40 CHdNOH 4-F-C6H5
TP
a
Human PARP-1 enzyme inhibition; values are an average of
b
at least two independent experiments; % error e (20%. Cytox-
icity of single agent. c Cytotoxicity of TP plus 0.4 µM corresponding
d
PARP-1 inhibitor. PF50 ) (IC50 of TP)/(IC50 of TP + 0.4 µM
a-d
PARP-1 inhibitor).
See Experimental Section for methods.
at C-6 and an aryl group at C-7 did not produce a
substantial increase in PARP-1 binding potency or in
vitro potentiation of TP cytotoxicity. Further crystal-
lographic studies may help lead to the design of an
improved class of 3,4-dihydro-2H-[1,4]diazepino[6,7,1-
hi]indol-1-one PARP-1 inhibitors with better cytotoxic
potentiation.
P oten tia tion of TP Gr ow th In h ibition Assa y. A549 cells
(ATCC, Rockville, MD) were seeded into 96 well cell culture
plates (Falcon brand, Fisher Scientific, Pittsburgh, PA) 16-
24 h before experimental manipulation. The cells were then
Exp er im en ta l Section
treated with
a test compound (or a combination of test
Proton magnetic resonance spectra (NMR) were determined
using a Bruker Avance 300DPX or 500DRX spectrometer
operating at a field strength of 300 and 500 MHz, respectively.
Chemical shifts are reported in parts per million (δ) with
references set such that in CDCl3 the CHCl3 is at 7.26 ppm,
in acetone-d6 the acetone is at 2.02 ppm, and in DMSO-d6 the
DMSO is at 2.49 ppm. Standard and peak multiplicities are
designated as follows: s, singlet; doublet; dd, doublet of
doublets; t, triplet; q, quartet; br s, broad singlet; and m;
multiplet. Mass spectra were determined at the University of
California, Riverside, or Scripps Research Institute, San Diego,
CA, Mass Spectrometry Facilities. Infrared absorption (IR)
spectra were taken on a MIDAC Corp. FTIR or a Perkin-Elmer
1600 series FTIR spectrometer. Elemental microanalyses were
performed by Atlantic Microlab Inc. (Norcoss, GA) and gave
results for the elements stated with (0.4% of the theoretical
values. Analytical HPLC was performed using a Hewlett-
Packard (HP) Series 1100 Quaternary system, equipped with
a HP 1100 variable wavelength detector set at 254 nm;
sensitivity, 0.02-50 AUFS. A Pheomenex Prodigy 5 ODS (3)
column (250 mm × 4.6 mm; 5 µm) was used. Typically, a
gradient mobile phase starting with 90% H2O with 0.1% TFA,
10% CH3CN with 0.1% TFA up to 20 min (min), then 35% H2O
with 0.1% TFA, 65% CH3CN with 0.1% TFA up to 25 min,
then 10% H2O with 0.1% TFA, 90% CH3CN with 0.1% TFA
thereafter was used. Flow rate ) 1 mL/min. Preparative HPLC
was performed using Gilson model 806 Manometric module,
equipped with a Gilson 811c dynamic mixer, two Gilson model
306 pumps, a Gilson 215 liquid handler, and a Gilson model
119 UV/visible detector set at 2145 or 220 and 254 nm;
sensitivity, 0.02-50 AUFS. A Metasil AQ C18 column (250
mm × 212 mm; 10 µm) was used. Typically, a gradient mobile
phase starting with 90% H2O with 0.1% TFA, 10% CH3CN
with 0.1% TFA up to 2 min, then reaching 35% H2O with 0.1%
TFA, 65% CH3CN with 0.1% TFA after 22 min or 90% 0.1M
compounds where indicated) each at a concentration of 0.4 µM
for either 3 or 5 days. At the end of treatments, the relative
cell number was determined by either MTT assay or SRB
assay. For the MTT assay, 0.2 µg/µL of MTT [3-(4,5-dimethyl-
thiazol-2-yl)-2,5-diphenyltetrazolium bromide] (Sigma Chemi-
cal Co., St. Louis, MO) was added to each well of a plate, and
the plate was incubated in a cell culture incubator for 4 h.
Metabolized MTT in each well was solubilized in 159 µL of
DMSO (Sigma Chemical Co.) with shaking and quantified with
a Wallac 1420 Victor plate reader (EG&G Wallad, Gaithers-
burg, MD) at 540 nm. For the SRB assay, the cells were fixed
with 10% trichloroacetic acid (Sigma Chemical Co.) for an hour
at 4 °C. After they were extensively washed, fixed cells were
stained for 30 min with 0.4% sulforhodamine B (SRB, Sigma
Chemical Co.) in 1% acetic acid (Sigma Chemical Co.). Un-
bound SRB was washed away with 1% acetic acid. Then, the
cultures were air-dried, and bound dye was solubilized with
10 mM unbuffered Tris base (Sigma Chemical Co.) with
shaking. The bound dye was measured photometrically with
the Wallac Victor plate reader at 515 nm. The ratio of the OD
(optical density) value of a compound-treated culture to the
OD value of a mock-treated culture, expressed in percentage,
was used to quantify the cytotoxicity of a compound. The
concentration at which a compound causes 50% cytotoxicity
is referred to as IC50. To quantify the potentiation of the
cytotoxicity of TP by test compounds, a dimensionless param-
eter PF50 is used and defined as the ratio of the IC50 of TP
alone to the IC50 of TP in combination with a test compound.
Cr ysta llogr a p h ic Meth od s. Purified protein and cocrys-
tals for the C-terminal catalytic domain of chicken PARP-1
were obtained using procedures similar to those previously
described. In this study, 100 mM Tris, pH 8.5, 16-32% PEG-
600, and 8% isopropyl alcohol were used as a precipitant. X-ray
diffraction data were collected with a MAR345 image plate to

3,4-Dihydro-2H-[1,4]diazepino[6,7,1-hi]indol-1-ones
J ournal of Medicinal Chemistry, 2004, Vol. 47, No. 22 5475
2.8 Å resolution. The space group is P212121, with a ) 59.31
Å, b ) 63.80 Å, and c ) 96.93 Å. The 19100 observations were
scaled and merged into 8942 unique reflections using DENZO
and SCALEPACK. The overall R-merge was 6.0%, the ratio
I/ σ(I) was 14.2, and the data were 94% complete. Correspond-
ing values for the high-resolution data shell (2.9-2.8 Å) were
16.4, 4.7, and 91.3%, respectively. The structure of 28 bound
to chicken PARP-1 was solved and refined using these data,
the program CNX,50 and the 2.2 Å protein and solvent model.29
The conventional and free R-factors for the refined model are
16.5 and 24%. The rms deviations between model and ideal
bond distances, bond angles, dihedral angels, and improper
angels are 0.007 Å, 1.3°, 22.7°, and 0.8°.
7-Meth yl-3,4-d ih yd r o-2H-[1,4]d ia zep in o[6,7,1-h i]in d ol-
1-on e (5). Acetate 4a (0.508 g, 1.97 mmol) was dissolved in
MeOH (70 mL) and glacial acetic acid (30 mL). Pd/C (10%)
(0.076 g) was added, and the suspension was stirred under an
atmosphere of H2 for 4.5 h at room temperature. The black
suspension was filtered, and the filtrate was concentrated to
give a white solid, which was purified by flash silica gel
chromatography eluting with a gradient of 0-1% MeOH in
CHCl3 to give 0.296 g (75%) of the product; mp 135-137 °C.
1H NMR (DMSO-d6): δ 2.52 (s, 3H), 3.51-3.54 (m, 2H), 4.27-
4.28 (m, 2H), 7.11 (t, 1H, J ) 7.5 Hz), 7.15 (s, 1H), 7.69 (d,
1H, J ) 7.5 Hz), 7.81 (d, 1H, J ) 7.5 Hz), 8.22-8.24 (m, 1H).
HRMS calcd for
C
12H12N2O (M+), 200.0950; found (M+),
200.0955. Anal. (C12H12N2O) C, H, N.
Com p u ta tion a l Meth od s. Molecular modeling of inhibi-
tors with a chimeric human PARP-1 model was performed with
Macromodel version 5.5.51 The model was created from the
X-ray structure of compound 28 complexed with chicken
PARP-1; however, residue 763 was changed from a glutamine
to a glutamate. A Monte Carlo conformational search of the
Glu-763 side chain was performed using the Amber* force field.
6-Iod o-7-m et h yl-3,4-d ih yd r o-2H -[1,4]d ia zep in o[6,7,1-
h i]in d ol-1-on e (6). To a solution of 5 (0.030 g, 0.150 mmol)
in CH2Cl2 (5 mL) was added iodine (0.038 g, 0.150 mmol) and
bistrifluoroacetoxyiodobenzene (0.077 g, 0.180 mmol). The
reaction mixture was stirred at room temperature for 5 min,
diluted with CH2Cl2, and washed with 10% Na2S2O3. The
organic layer was dried over anhydrous MgSO4 and concen-
trated. The residue was purified by flash silica gel chroma-
tography eluting with a gradient of 0-1% MeOH in CHCl3 to
give 0.026 g (53%) of the desired product. 1H NMR (DMSO-
d6): δ 2.20 (s, 3H), 3.33-3.35 (br s, 2H), 4.32-4.35 (br s, 2H),
7.10 (t, 1H, J ) 7.5 Hz), 7.60 (d, 1H, J ) 7.5 Hz), 7.80 (d, 1H,
J ) 7.5 Hz), 8.30 (br s, 1H).
7-Meth yl-6-p h en yl-3,4-d ih yd r o-2H-[1,4]d ia zep in o[6,7,1-
h i]in d ol-1-on e (7). To a solution of the iodide 6 (0.024 g, 0.736
mmol) in DMF (3 mL) was added phenylboronic acid (0.010 g,
0.0810 mmol), Na2CO3 (0.020 g, 0.184 mmol) dissolved in
minimum H2O, LiCl (0.010 g, 0.221 mmol), and tetrakistri-
phenylphosphine palladium (5.0 mg, 0.0037 mmol) at room
temperature. The reaction mixture was stirred at 80-90 °C
for 19 h, and then, the solvent evaporated. The residue was
taken up in H2O and extracted with EtOAc several times. The
combined organic layers were dried over anhydrous MgSO4
and concentrated to give a brown solid. The crude mixture was
purified by flash silica gel chromatography eluting with a
gradient of 0-1% MeOH in CHCl3 to give 0.014 g (70%) of the
product; mp 278-280 °C. 1H NMR (DMSO-d6): δ 2.23 (s, 3H),
3.46 (br s, 2H), 4.13 (br s, 2H), 7.17 (t, 1H, J ) 7.5 Hz), 7.45-
7.56 (m, 5H), 7.76 (d, 1H, J ) 7.5 Hz), 7.84 (d, 1H, J ) 7.5
Hz), 8.29-8.31 (m, 1H). LRMS (M+) 276. Anal. (C18H16N2O‚
0.4 H2O) C, H, N.
Meth od A. 3,4,6,7-Tetr a h yd r o-2H-[1,4]d ia zep in o[6,7,1-
h i]in d ol-1-on e (1).40 1H NMR (DMSO-d6): δ 2.92 (t, 2H, J )
7.5 Hz), 3.29-3.31 (m, 4H), 3.47 (t, 2H, J ) 7.5 Hz), 6.49 (t.
1H, J ) 7.5 Hz), 7.04 (d, 1H, J ) 7.5 Hz), 7.49 (d, 1H J ) 7.5
Hz), 7.86 (br s, 1H). HRMS calcd for C11H12N2O (M+), 188.0950;
found (M+), 188.0957. Anal. (C11H12N20) C, H, N.
3,4-Dih ydr o-2H-[1,4]diazepin o[6,7,1-h i]in dol-1-on e (2).40
mp 165-167 °C. 1H NMR (DMSO-d6): δ 3.52-3.56 (m, 2H),
4.31-4.36 (m, 2H), 6.53 (d, 1H J ) 3.0 Hz), 7.11 (t, 1H J )
6.0 Hz), 7.38 (d, 1H, J ) 3.0 Hz), 7.70 (d, 1H, J ) 6.0 Hz),
7.80 (d, 1H, J ) 6.0 Hz), 8.30 (br s, 1H). LRMS (M+) 186. Anal.
(C11H10N2O‚0.05H2O) C, H, N.
1-Oxo-1,2,3,4-tetr a h yd r o[1,4]d ia zep in o[6,7,1-h i]in d ole-
7-ca r ba ld eh yd e (3). POCl3 (16.37 g, 106.76 mmol) was slowly
added to DMF (225 mL) at 0 °C. The mixture was stirred for
15 min and then was treated with a solution of 2 (1.46 g, 7.85
mmol) in DMF (10 mL). The reaction mixture was warmed to
room temperature and stirred for 17 h. After all of the solvent
was removed, the residue was taken up in H2O, made basic
(pH 12) using 20% aqueous NaOH, and extracted with EtOAc
several times. The organic layer was dried over anhydrous
MgSO4 and concentrated to give a pale yellow solid, which was
used without further purification; mp 238-240 °C. 1H NMR
(DMSO-d6): δ 3.58-3.61 (m, 2H), 4.48 (br s, 2H), 7.37 (t, 1H,
J ) 7.5 Hz), 7.97 (d, 1H, J ) 7.5 Hz), 8.33-8.35 (m, 2H), 8.43-
8.45 (m, 1H), 9.95 (s, 1H). HRMS calcd for C12H10N2O2 (M+),
214.0742; found (M+), 214.0737. Anal. (C12H10 N2O2‚0.1H2O)
C, H, N.
Compounds 8 and 9 were prepared from 6 using method A.
6-(4-Flu or o-ph en yl)-7-m eth yl-3,4-dih ydr o-2H-[1,4]diaze-
p in o[6,7,1-h i]in d ol-1-on e (8). White solid (73%); mp 270-
1
272 °C. H NMR (DMSO-d6): δ 2.77 (s, 3H), 3.74 (br s, 2H),
7-Hyd r oxym eth yl-3,4-d ih yd r o-2H-[1,4]d ia zep in o[6,7,1-
h i]in d ol-1-on e (4). Sodium borohydride (0.018 g, 0.466 mmol)
was added to a suspension of 3 (0.050 g, 0.233 mmol) in 15
mL EtOH. The reaction mixture was refluxed for 1.5 h and
cooled, and the solvent was evaporated. The residue was
partitioned between 1% aqueous NaOH and EtOAc. The
organic extract was dried over anhydrous MgSO4 and evapo-
rated to give a pale yellow solid (88%); mp 180-182 °C. 1H
NMR (DMSO-d6): δ 3.52-3.55 (m, 2H), 4.31 (br s, 2H), 4.63
(d, 2H, J ) 5 Hz), 4.84 (t, 1H, J ) 5 Hz), 7.12 (t, 1H, J ) 7.5
Hz), 7.29 (s, 1H), 7.80-7.83 (m, 2H), 8.24-8.26 (m, 1H). HRMS
calcd for C12H12N2O2 (M+), 216.0899; found (M+), 216.0908;
Anal. (C12H12N2O2‚0.2H2O) C, H, N.
3.39-4.37 (m, 2H), 7.45 (t, 1H, J ) 7.5 Hz), 7.63-7.67 (m, 2H),
7.81-7.83 (m, 2H), 8.04 (d, 1H, J ) 7.5 Hz), 8.12 (d, 1H, J )
7.5 Hz), 8.57-8.59 (m, 1H). HRMS calcd for C18H15N2OF (M+),
294.1168; found (M+), 294.1175. Anal. (C18H15N2OF‚0.1H2O)
C, H, N.
7-Meth yl-6-(3-tr iflu or om eth yl-p h en yl)-3,4-d ih yd r o-2H-
[1,4]d ia zep in o[6,7,1-h i]in d ol-1-on e (9). White solid (81%);
mp 258-260 °C. 1H NMR (DMSO-d6): δ 2.25 (s, 3H), 3.44-
3.48 (m, 2H), 4.13-4.16 (m, 2H), 7.19 (t, 1H, J ) 7.5 Hz), 7.77-
7.88 (m, 6H), 8.32-8.36 (m, 1H). HRMS calcd for C19H15N2OF3
(M+), 344.136; found (M+), 344.1136. Anal. HPLC Rt ) 14.9
min. Purification done using preparative HPLC. A gradient
mobile phase, starting with 90% 0.1 M NH4OAc, 10% CH3CN
up to 2 min, then reaching 100% CH3CN after 22 min, was
used. Rt ) 17.59 min.
Meth od B. 8-Iod o-2,3-d ih yd r o-1H-qu in olin -4-on e (11).
A mixture of the acid 3-(2-iodo-phenylamino)propionaldehyde
carboxylic acid 1042 (0.103 g, 0.354 mmol) in 7% P2O5:CH3SO3H
(Eaton’s reagent)43 (2 mL) was heated at 60-70 °C for 3 h.
Ice-cold water was added to the reaction mixture, made basic
(pH 12) with 50 wt % NaOH, and extracted with EtOAc several
times. The combined organic extracts were dried over anhy-
Acet ic Acid 1-Oxo-1,2,3,4-t et r a h yd r o[1,4]d ia zep in o-
[6,7,1-h i]in d ol-7-ylm eth yl Ester (4a ). 4-(Dimethylamino)-
pyridine (0.057 g, 0.466 mmol) was added to a solution of the
alcohol 4 (1.007 g, 4.66 mmol) in a mixture of acetic anhydride
(1.1 mL, 11.65 mmol) and pyridine (25 mL). The mixture was
stirred for 15 h at room temperature, and then, the solvent
evaporated. The residue was purified by flash silica gel
chromatography eluting with a gradient of 0-3% MeOH in
1
CHCl3 to give 0.925 g (77%) of the acetate. H NMR (DMSO-
d6): δ 2.0 (s, 3H), 3.42-3.44 (br s, 2H), 4.23-4.25 (br s, 2H),
5.30 (s, 2H), 9.10 (t, 1H, J ) 7.5 Hz), 7.50 (s, 1H), 7.75 (d, 1H,
J ) 7.5 Hz), 7.85 (d, 1H, J ) 7.5 Hz), 8.30 (m, 1H).
drous MgSO4 and concentrated to give 0.070 g (72%) of the
product as orange oil. The product was used without further
purification. 1H NMR (CDCl3): δ 2.71 (t, 2H, J ) 6.0 Hz), 3.65

5476 J ournal of Medicinal Chemistry, 2004, Vol. 47, No. 22
Tikhe et al.
(t, 2H, J ) 6.0 Hz), 4.86 (br s, 1H), 6.50 (t, 1H, J ) 9.0 Hz),
7.79 (d, 1H, J ) 9.0 Hz), 7.85 (d, 1H, J ) 9.0 Hz). LRMS (M
+ H) 272.
7.29 (m, 5H), 7.65 (d, 1H, J ) 6.0 HZ), 7.74 (d, 1H, J ) 6.0
Hz), 8.26 (t, 1H, J ) 6.0 Hz). HRMS calcd for C19H18N2O (M+),
290.1419; found (M+), 290.1421. Anal. (C19H18N2O) C, H, N.
9-Iod o-1,2,3,4-t e t r a h yd r o-b e n zo[e][1,4]d ia ze p in -5-
on e (12). To a solution of 11 (3.47 g, 0.0127 mmol) in CH3SO3H
(50 mL) was added NaN3 (1.074 g, 0.0165 mmol) slowly at room
temperature. The reaction mixture was stirred at room tem-
perature for 0.5 h. Upon consumption of starting material by
TLC, ice-cold water was added to the reaction mixture and
made basic (pH 13) using 50 wt % NaOH whereupon the
product (3.05 g, 83%) precipitates. The solids were filtered,
washed with water, and dried; mp 182-184 °C. 1H NMR
(DMSO-d6): δ 3.25-3.27 (m, 2H), 3.48 (br s, 2H), 5.43 (br s,
1H), 6.41 (t, 1H, J ) 6.0 Hz), 7.73 (d, 1H, J ) 6.0 Hz), 7.80 (d,
1H, J ) 6.0 Hz), 8.15 (br s, 1H). LRMS (M+) 288.
6-P yr id in -2-yl-3,4-d ih yd r o-2H-[1,4]d ia zep in o[6,7,1-h i]-
in d ol-1-on e (19). To a solution of 9-pyridin-2-ylethynyl-
1,2,3,4-tetrahydro-benzo[e][1,4]diazepin-5-one (0.050 g, 0.190
mmol) in DMF (6 mL) were added CuI (0.003 g, 0.012 mmol)
and PdCl2 (5.0 mg, 0.029 mmol) at room temperature. The
reaction mixture was heated at 80-85 °C for 4 h. Upon
completion, the solvent was evaporated to dryness. The crude
residue was purified by flash silica gel chromatography eluting
with a gradient of 0-3% MeOH in CHCl3 to give 0.010 g (20%)
of the product. 1H NMR (DMSO-d6): δ 3.38-3.55 (m, 2H), 4.64
(br s, 2H), 7.06 (s, 1H), 7.19 (t, 1H, J ) 9.0 Hz), 7.37-7.41 (m,
1H), 7.82-7.96 (m, 4H), 8.38 (t, 1H, J ) 6.0 Hz), 8.70 (d, 1H,
J ) 3.0 Hz). HRMS calcd for C16H13N3O (M+), 263.1059; found
(M+), 263.1062. Anal. (C16H13N3O‚0.8 H2O) C, H, N.
Meth od C. 9-Tr im eth ylsila n yleth yn yl-1,2,3,4-tetr a h y-
d r o-ben zo[e][1,4]d ia zep in -5-on e (52). A mixture of 12 (1.0
g, 3.47 mmol), TMS acetylene (5.0 mL, 34.70 mmol), tetrakis-
triphenylphosphine palladium chloride (0.040 g, 0.0347 mmol),
CuI (0.013 g, 0.0694 mmol) in diethylamine (10 mL), and DMF
(10 mL) was stirred at room temperature for 5 h. The solvent
was evaporated, and the residue was taken up in H2O and
extracted with EtOAc several times. The combined organic
layers were dried over anhydrous MgSO4 and concentrated.
The crude mixture was purified by flash silica gel chromatog-
raphy eluting with a gradient of 0-5% MeOH in CHCl3 to give
0.733 g (82%) of a brown solid; mp 180-182 °C. 1H NMR
(DMSO-d6): δ 0.25 (s, 9H), 3.25-3.33 (m, 2H), 3.51-3.55 (m,
2H), 5.90 (br s, 1H), 6.57 (t, 1H, J ) 6.0 Hz), 7.35 (d, 1H, J )
6.0 Hz), 7.78 (d, 1H, J ) 6.0 Hz), 8.13 (t, 1H, J ) 6.0 Hz).
LRMS (M+) 258.
9-Eth yn yl-1,2,3,4-tetr a h yd r o-ben zo[e][1,4]d ia zep in -5-
on e (53). A mixture of 52 (0.712 g, 2.76 mmol) and K2CO3
(0.038 g, 0.276 mmol) in MeOH (35 mL) was stirred at room
temperature for 2.5 h. The solvent was evaporated, and the
residue taken up in H2O and extracted with EtOAc several
times. The combined organic extracts were dried over anhy-
drous MgSO4 and concentrated to give 0.504 g (98%) of a brown
solid. The solid was used without further purification; mp 146-
148 °C. 1H NMR (DMSO-d6): δ 3.15-3.23 (m, 2H), 3.48-3.52
(m, 2H), 4.50 (s, 1H), 6.13 (br s, 1H), 6.57 (t, 1H, J ) 9.0 Hz),
7.37 (d, 1H, J ) 9.0 Hz), 7.79 (d, 1H, J ) 9.0 Hz), 8.10 (t, 1H,
J ) 6.0 Hz). LRMS (M+) 186.
3-(5-Oxo-2,3,4,5-tetr a h yd r o-1H-ben zo[e][1,4]d ia zep in -
9-yleth yn yl)ben za ld eh yd e (54). Using the procedure de-
scribed for the preparation of 13, 3-iodobenzaldehyde and 53
were used to synthesize 54 in 62% yield as a yellow solid; mp
176-178 °C. 1H NMR (DMSO-d6): δ 3.30-3.33 (m, 2H), 3.54-
3.57 (m, 2H), 6.40 (br s, 1H), 6.63 (t, 1H, J ) 6.0 Hz), 7.49 (d,
1H, J ) 6.0 Hz), 7.66 (t, 1H, J ) 9.0 Hz), 7.83 (d, 1H, J ) 6.0
Hz), 7.90-7.97 (m, 2H), 8.15 (br s, 1H), 8.31 (s, 1H), 10.03 (s,
1H). LRMS (M++ H) 291.
9-P h en yleth yn yl-1,2,3,4-tetr a h yd r o-ben zo[e][1,4]d ia ze-
p in -5-on e (13a ). A mixture of 12 (0.144 g, 0.5 mmol),
phenylacetylene (0.055 mL, 0.5 mmol), tetrakistriphenylphos-
phine palladium chloride (6 mg, 0.005 mmol), CuI (2 mg, 0.01
mmol) in diethylamine (4 mL), and DMF (2 mL) was stirred
at room temperature for 2 h. The solvent was evaporated to
dryness, and the residue was taken in water and extracted
with EtOAc. The organic extract was dried over anhydrous
MgSO4 and concentrated. The crude mixture was purified by
flash silica gel chromatography eluting with a gradient of
0-3% MeOH in CHCl3 to give 0.102 g (78%) of the desired
product. 1H NMR (DMSO-d6): δ 3.27-3.29 (m, 2H), 3.53-3.56
(m, 2H), 6.26 (t, 1H, J ) 6.0 Hz), 6.61 (t, 1H, J ) 6.0 Hz),
7.40-7.47 (m, 4H), 7.62-7.65 (m, 2H), 7.80 (d, 1H, J ) 6.0
Hz), 8.13 (t, 1H, J ) 6.0 Hz). LRMS (M+) 262. IR (KBr) 3400,
3190, 3051, 1641, 1589, 1518, 1446, 1250, 756, 690 cm-1
.
6-P h en yl-3,4-d ih yd r o-2H-[1,4]d ia zep in o[6,7,1-h i]in d ol-
1-on e (14). To a clear solution of 13a (0.08 g, 0.305 mmol) in
CH3CN (10 mL) was added PdCl2 (3.0 mg, 0.0153 mmol) at
room temperature. The reaction mixture was heated at 70-
80 °C for 3.5 h. Upon consumption of starting material (TLC),
the solvent was evaporated and the crude residue was purified
by flash silica gel chromatography eluting with a gradient of
0-3% MeOH in CHCl3 to give 0.058 g (73%) of the desired
product; mp 165-167 °C. 1H NMR (DMSO-d6): δ 3.46-3.51
(m, 2H), 4.31-4.33 (m, 2H), 6.71 (s, 1H), 7.17 (t, 1H, J ) 9.0
Hz), 7.42-7.55 (m, 3H), 7.60-7.63 (m, 2H), 7.78 (d, 1H, J )
9.0 Hz), 7.82 (d, 1H, J ) 9.0 Hz), 8.38 (t, 1H, J ) 6.0 Hz).
HRMS calcd for
C
17H14N2O (M+), 262.1106; found (M+),
262.1109. Anal. (C17H14N2O‚0.1H2O) C, H, N.
Compounds 15-18 were made using method B.
6-(4-Ch lor o-ph en yl)-3,4-dih ydr o-2H-[1,4]diazepin o[6,7,1-
h i]in d ol-1-on e (15). Pale yellow solid (69%); mp 238-240 °C.
1H NMR (DMSO-d6): δ 3.47-3.50 (m, 2H), 4.29-4.32 (m, 2H),
6.74 (s, 1H), 7.18 (t, 1H, J ) 9.0 Hz), 7.58 (d, 2H, 9.0 Hz), 7.65
(d, 2H, J ) 9.0 Hz), 7.80 (d, 2H, J ) 9.0 Hz), 7.83 (d, 2H, J )
9.0 Hz), 8.39 (t, 1H, J ) 4.5 Hz). HRMS calcd for C17H13N2-
OCl (M+), 296.0716; found (M+), 296.0715. Anal. (C17H13N2-
OCl) C, H, N.
6-(4-Met h oxy-p h en yl)-3,4-d ih yd r o-2H -[1,4]d ia zep in o-
[6,7,1-h i]in d ol-1-on e (16). Pale yellow solid (84%); mp 188-
190 °C. 1H NMR (DMSO-d6): δ 3.48-3.50 (m, 2H), 4.27-4.30
(m, 2H), 6.60 (s, 1H), 7.07 (d, 2H, J ) 9.0 Hz), 7.15 (t, 1H, J
) 6.0 Hz), 7.54 (d, 2H, J ) 9.0 Hz), 7.75 (d, 1H, J ) 6.0 HZ),
7.79 (d, 1H, J ) 6.0 Hz), 8.36 (t, 1H, J ) 6.0 Hz). HRMS calcd
for C18H16N2O2 (M+), 292.1212; found (M+), 292.1218. Anal.
(C18H16N2O2‚0.1H2O) C, H, N.
3-(1-Oxo-1,2,3,4-tetr ah ydr o[1,4]diazepin o[6,7,1-h i]in dol-
6-yl)ben za ld eh yd e (55). Using the procedure described for
the preparation of 14, compound 54 was converted to 55 in
66% yield as a pale yellow solid; mp 192-194 °C. 1H NMR
(DMSO-d6): δ 3.49-3.51 (m, 2H), 4.33-4.36 (m, 2H), 6.83 (s,
1H), 7.19 (t, 1H, J ) 6.0 Hz), 7.75 (t, 1H, J ) 9.0 Hz), 7.80-
7.86 (m, 2H), 7.96 (d, 2H, J ) 6.0 Hz), 8.15 (s, 1H), 8.41 (t,
1H, J ) 6.0 Hz), 10.11 (s, 1H). LRMS (M+) 290.
6-(4-Flu or o-ph en yl)-3,4-dih ydr o-2H-[1,4]diazepin o[6,7,1-
h i]in d ol-1-on e (17). Pale yellow solid (79%); mp 198-200 °C.
1H NMR (DMSO-d6): δ 3.48-3.50 (m, 2H), 4.28-4.30 (m, 2H),
6.70 (s, 1H), 7.15 (t, 1H, J ) 6.0 Hz), 7.33-7.39 (m, 2H), 7.65
(d, 1H, J ) 6.0 Hz), 7.68 (d, 1H, J ) 6.0 Hz), 7.78 (d, 1H, J )
6.0 Hz), 7.82 (d, 1H, J ) 6.0 Hz), 8.38 (t, 1H, J ) 6.0 Hz).
HRMS calcd for C17H13N2OF (M+), 280.1012; found (M+),
280.1002. Anal. (C17H13N2OF) C, H, N.
6-P h en et h yl-3,4-d ih yd r o-2H -[1,4]d ia zep in o[6,7,1-h i]-
in d ol-1-on e (18). Pale yellow solid (70%); mp 188-190 °C.
1H NMR (DMSO-d6): δ 2.96-3.06 (m, 4H), 3.49-3.50 (m, 2H),
4.21 (br s, 2H), 6.37 (s, 1H), 7.07 (t, 1H, J ) 6.0 Hz), 7.18-
6-(3-Dim et h yla m in om et h yl-p h en yl)-3,4-d ih yd r o-2H -
[1,4]d ia zep in o[6,7,1-h i]in d ol-1-on e (20). Dimethylamine (2
M) in methanol (16.34 mmol, 8.2 mL) was added to a suspen-
sion of 55 (1.90 mmol, 0.55 g) in MeOH (110 mL) at room
temperature. The reaction mixture was heated to reflux until
the suspended solids went into solution. The reaction mixture
was cooled to room temperature, and a solution of NaCNBH3
(2.09 mmol, 0.131 g) and ZnCl2 (1.05 mmol, 0.143 g) in MeOH
(55 mL) was slowly added. The pH of the reaction was adjusted
to 3-4 using 2 M methanolic HCl. The reaction mixture was
stirred at room temperature for 2.5 h. Upon completion (TLC),
concentrated HCl was added (pH 1) and the solvent was

3,4-Dihydro-2H-[1,4]diazepino[6,7,1-hi]indol-1-ones
J ournal of Medicinal Chemistry, 2004, Vol. 47, No. 22 5477
removed in vacuo. The residue was diluted with H2O, made
basic (pH 12-14) with 50% aqueous NaOH, and extracted with
EtOAc several times. The combined organic layers were dried
over anhydrous MgSO4 and concentrated. The crude mixture
was purified by flash silica gel chromatography eluting with
a gradient of 0-7% MeOH in CHCl3 followed by 3-7% MeOH/
NH3 in CHCl3 to give 0.527 g (87%) of a white solid; mp 98-
mL, 0.747 mmol) was added to a mixture of 26 (0.074 g, 0.37
mmol) and bistriphenylphosphine palladium chloride (8.4 mg,
0.012 mmol) in 8 mL of MeOH and 3 mL of DMF at room
temperature. The reaction mixture was heated at 50-55 °C
for 18 h under a CO atmosphere (balloon). The solvent was
removed under vacuo, and the residue was taken up in EtOAc
and washed with water. The organic layer was dried over
anhydrous MgSO4 and concentrated to give a yellow solid,
which was purified by flash silica gel chromatography eluting
with a gradient of 0-3% MeOH in CHCl3 to give 0.025 g of
the methyl ester; mp 259-261 °C. 1H NMR (DMSO-d6): δ
3.34-3.60 (m, 2H), 3.83 (s, 3H), 4.46 (br s, 2H), 7.36 (t, 1H, J
) 7.5 Hz), 7.95 (d, 1H, J ) 7.5 Hz), 8.23 (s, 1H), 8.27 (d, 1H,
J ) 7.5 Hz), 8.40-8.50 (m 1H). HRMS calcd for C13H12N2O3
(M+), 244.0848; found (M+), 244.0850. Anal. (C13H12N2O3‚0.25
H2O) C, H, N.
1
100 °C. H NMR (DMSO-d6): δ 2.18 (s, 6H), 3.47 (br s, 4H),
4.30-4.32 (m, 2H), 6.70 (s, 1H), 7.17 (t, 1H, J ) 6.0 Hz), 7.35-
7.37 (m, 1H), 7.43-7.50 (m, 3H), 7.78 (d, 1H, J ) 6.0 Hz), 7.81
(d, 1H, J ) 6.0 Hz), 8.38 (t, 1H, J ) 6.0 Hz). HRMS calcd for
C
20H21N3O (M+), 319.1685; found (M+), 319.1682; Anal.
(C20H21N3O‚ 0.25 H2O) C, H, N.
Compounds 21-25 were made using method C.
6-(3-Meth yla m in om eth yl-p h en yl)-3,4-d ih yd r o-2H-[1,4]-
d ia zep in o[6,7,1-h i]in d ol-1-on e (21). Pale yellow solid (94%);
1
1-Oxo-1,2,3,4-tetr a h yd r o[1,4]d ia zep in o[6,7,1-h i]in d ole-
7-ca r ba ld eh yd e Oxim e (28). To a mixture of 3 (0.050 g, 0.233
mmol) in EtOH (5 mL) and H2O (0.5 mL) were added
NH2OH‚HCl (0.041 g, 0.583 mmol) and NaOH (0.024 g, 0.583
mmol) at room temperature. The reaction mixture was heated
at 80-85 °C for 2 days. The resulting suspension was filtered,
and the white solid (0.047 g) was washed with water and dried;
mp 128-130 °C. H NMR (DMSO-d6): δ 2.29 (s, 3H), 3.48 (br
s, 2H), 3.71 (s, 2H), 4.30-4.33 (m, 2H), 6.69 (s, 1H), 7.17 (t,
1H, J ) 9.0 Hz), 7.38-7.39 (m, 1H), 7.44-7.46 (m, 2H), 7.54
(s, 1H), 7.80 (t, 2H, J ) 9.0 Hz), 8.39 (t, 1H, J ) 6.0 Hz). HRMS
calcd for C19H19N3O (M+), 305.3828; found (M+), 305.1520.
Anal. (C19H19N3O‚0.6 H2O) C, H, N.
6-(3-P yr r olidin -1-ylm eth yl-ph en yl)-3,4-dih ydr o-2H-[1,4]-
1
mp 262-264 °C. H NMR (DMSO-d6): δ 3.56 (br s, 2H), 4.36
d ia zep in o[6,7,1-h i]in d ol-1-on e (22). Pale yellow solid (92%);
1
(br s, 2H), 7.23 (t, 1H, J ) 7.5 Hz), 7.68 (s, 1H), 7.90 (d, 1H, J
) 7.5 Hz), 8.21 (d, 1H, J ) 7.5 Hz), 8.26 (s, 1H), 8.33-8.35
(m, 1H), 10.66 (s, 1H). HRMS calcd for C12H11N3O2 (M+),
229.0851; found (M+), 229.0843. Anal. (C12H11N3O2) C, H, N.
mp 158-160 °C. H NMR (DMSO-d6): δ 1.71 (br s, 4H), 2.49
(br s, 4H), 3.49 (br s, 2H), 3.68 (br s, 2H), 4.30-4.33 (m, 2H),
6.70 (s, 1H), 7.17 (t, 1H, J ) 9.0 Hz), 7.38-7.52 (m, 4H), 7.79
(d, 1H, J ) 9.0 Hz), 7.82 (d, 1H, J ) 9.0 Hz), 8.38 (t, 1H, J )
6.0 Hz). HRMS calcd for C22H23N3O (M+), 345.1841; found
(M+), 345.1848. Anal. (C22H23N3O‚0.4 H2O) C, H, N.
1-Oxo-1,2,3,4-tetr a h yd r o[1,4]d ia zep in o[6,7,1-h i]in d ole-
7-ca r ba ld eh yd e O-Meth yl-oxim e (29 a n d 30). A solution
3 (0.050 g, 0.234 mmol) and MeONH2‚HCl (0.020 g, 0.242
mmol) in EtOH (5 mL) and pyridine (5 mL) was refluxed for
20 h. The reaction mixture was then evaporated to dryness.
The residue was taken up in H2O and extracted with EtOAc
several times. The combined organic layers were dried over
anhydrous MgSO4 and concentrated. The crude was purified
by flash silica gel chromatography eluting with a gradient of
0-1% MeOH in CHCl3 to give 0.036 g of the (E) and 0.013 g
of the (Z) isomer.
6-(4-Dim et h yla m in om et h yl-p h en yl)-3,4-d ih yd r o-2H -
[1,4]d ia zep in o[6,7,1-h i]in d ol-1-on e (23). Pale yellow solid
1
(86%); mp 140-142 °C. H NMR (DMSO-d6): δ 2.18 (s, 6H),
3.45 (s, 2H), 3.47-3.50 (m, 2H), 4.32 (m, 2H), 6.69 (s, 1H), 7.16
(t, 1H, J ) 10.0 Hz), 7.42 (d, 2H, J ) 10 Hz), 7.56 (d, 2H, J )
10 Hz), 7.77 (d, 1H, J ) 10 Hz), 7.81 (d, 1H, J ) 10.0 Hz),
8.36 (t, 1H, J ) 5.0 Hz). HRMS calcd for C20H21N3O (M+),
319.1685; found (M+), 319.1678. Anal. (C20H21N3O‚0.3 H2O) C,
H, N.
Com p ou n d 29. (E) isomer: mp 173-175 °C. 1H NMR
(DMSO-d6): δ 3.55 (br s, 2H), 3.87 (s, 3H), 4.37 (br s, 2H),
7.27 (t, 1H, J ) 7.5 Hz), 7.75 (s, 1H), 7.91 (d, 1H, J ) 7.5 Hz),
8.24 (d, 1H, J ) 7.5 Hz), 8.34-8.38 (m, 2H). HRMS calcd for
6-(4-Meth yla m in om eth yl-p h en yl)-3,4-d ih yd r o-2H-[1,4]-
d ia zep in o[6,7,1-h i]in d ol-1-on e (24). Pale yellow solid (71%);
1
mp 178-180 °C. H NMR (DMSO-d6): δ 2.29 (s, 3H), 3.48 (br
s, 2H), 3.70 (s, 2H), 4.30-4.33 (m, 2H), 6.68 (s, 1H), 7.16 (t,
1H, J ) 9.0 Hz), 7.45 (d, 2H, J ) 9.0 Hz), 7.55 (d, 2H, J ) 9.0
Hz), 7.77 (d, 1H, J ) 9.0 Hz), 7.80 (d, 1H, J ) 9.0 Hz), 8.38 (t,
1H, J ) 6.0 Hz). HRMS calcd for C19H19N3O (M+), 305.3828;
found (M+), 305.1536. Anal. (C19H19N3O‚0.1H2O) C, H, N.
6-(4-P yr r olidin -1-ylm eth yl-ph en yl)-3,4-dih ydr o-2H-[1,4]-
d ia zep in o[6,7,1-h i]in d ol-1-on e (25). Pale yellow solid (76%);
C
13H13N3O2 (M+), 243.1008; found (M+), 243.1016. Anal.
(C13H13N3O2‚0.25 H2O) C, H, N.
Com p ou n d 30. (Z) isomer: mp 210-212 °C. 1H NMR
(DMSO-d6): δ 3.54-3.58 (m, 2H), 3.96 (s, 3H), 4.43 (br s, 2H),
7.27 (t, 1H, J ) 9.0 Hz), 7.89-7.92 (m, 2H), 8.14 (d, 1H, J )
9.0 Hz), 8.21 (s, 1H), 8.35-8.39 (m, 1H). HRMS calcd for
C
13H13N3O2 (M+), 243.1008; found (M+), 243.1020. Anal.
1
mp 146-148 °C. H NMR (DMSO-d6): δ 1.71 (br s, 4H), 2.49
(C13H13N3O2‚0.1H2O‚0.1EtOAc) C, H, N.
(br s, 4H), 3.48 (br s, 2H), 3.64 (br s, 2H), 4.30-4.33 (m, 2H),
6.69 (s, 1H), 7.16 (t, 1H, J ) 9.0 Hz), 7.43 (d, 2H, J ) 9.0 Hz),
7.55 (d, 2H, J ) 9.0 Hz), 7.77 (d, 1H, J ) 9.0 Hz), 7.80 (d, 1H,
7-(1-Hydr oxy-eth yl)-3,4-dih ydr o-2H-[1,4]diazepin o[6,7,1-
h i]in d ol-1-on e (31). MeLi (1.5 M) (3.744 mmol, 2.5 mL) was
added to a solution of 3 (1.17 mmol, 0.250 g) in 100 mL of
THF at -78 °C. The reaction mixture was warmed to room
temperature and stirred for 5-10 min. Upon consumption of
3 as indicated by TLC, the reaction was quenched with H2O
and then extracted with EtOAc several times. The combined
organic extracts were dried over anhydrous MgSO4 and
concentrated to give a yellow solid. The solid was purified by
flash silica gel chromatography eluting with a gradient of
0-5% MeOH in CHCl3 to give 0.222 g (69%) of a pale yellow
J
C
) 9.0 Hz), 8.38 (t, 1H, J ) 6.0 Hz). HRMS calcd for
22H23N3O (M+), 345.1841; found (M+), 345.1835. Anal.
(C22H23N3O‚0.25 H2O) C, H, N.
7-Iod o-3,4-d ih yd r o-2H-[1,4]d ia zep in o[6,7,1-h i]in d ol-1-
on e (26). To a pale yellow solution 2 (0.051 g, 0.274 mmol) in
5 mL of DMF were added KOH (0.058 g, 1.03 mmol) and iodine
(0.139 g, 0.548 mmol) at room temperature. The reaction
mixture was stirred at room temperature overnight. The
solvent was removed in vacuo, and the residue was taken up
in EtOAc and washed with 0.1% sodium bisulfite, H2O, and
brine. The organic layer was dried over anhydrous MgSO4 and
concentrated to give 0.078 g (92%) of a pale yellow solid, which
was used without further purification; mp 188-190 °C. 1H
NMR (DMSO-d6): δ 3.56-3.59 (m, 2H), 4.40 (m, 2H), 7.26 (t,
1H, J ) 7.5 Hz), 7.52 (d, 1H, J ) 7.5 Hz), 7.67 (s, 1H), 7.93 (d,
1H, J ) 7.5 Hz), 8.37 (t, 1H, J ) 5.3 Hz). HRMS calcd for
1
solid; mp 295-297 °C. H NMR (DMSO-d6): δ 1.47 (d, 3H, J
) 6.0 Hz), 3.50-3.55 (m, 2H), 4.29-4.31 (m, 2H), 4.95 (d, 1H,
J ) 6.0 Hz), 4.97-5.03 (m, 1H), 7.10 (t, 1H, J ) 6.0 Hz), 7.25
(s, 1H), 7.81 (d, 1H, J ) 6.0 Hz), 7.86 (d, 1H, J ) 6.0 Hz), 8.25
(t, 1H, J ) 6.0 Hz). HRMS calcd for C13H14N2O2 (M+), 231.1134;
found (M+), 231.1143. Anal. (C13H14N2O2) C, H, N.
7-Acetyl-3,4-d ih yd r o-2H-[1,4]d ia zep in o[6,7,1-h i]in d ol-
1-on e (32). o-Iodooxybenzoic acid (2.217 mmol, 0.621 g) was
added to a solution of 31 (0.739 mmol, 0.170 g) in DMSO (8
mL) at room temperature, and the mixture was stirred at for
2.5 h. The solvent was removed in vacuo, and the residue was
taken up in EtOAc and washed with 5% Na2S2O3/5% NaHCO3,
C
11H9N2OI (M+), 311.9761; found (M+), 311.9776. Anal. calcd
for C11H9N2O2I: % C, 42.33; % H, 2.91; % N, 8.98. Found: %
C, 42.81; % H, 2.98; % N, 8.85.
1-Oxo-1,2,3,4-tetr a h yd r o[1,4]d ia zep in o[6,7,1-h i]in d ole-
7-ca r boxylic Acid Meth yl Ester (27). Triethylamine (0.11

5478 J ournal of Medicinal Chemistry, 2004, Vol. 47, No. 22
Tikhe et al.
H2O, and brine. The organic layer was dried over anhydrous
MgSO4 and concentrated to give an orange solid. The solid was
purified by flash silica gel chromatography eluting with a
gradient of 0-5% MeOH in CHCl3 to give 0.094 g (75%) of a
EtOH (5 mL) and H2O (0.5 mL). After the reaction mixture
was heated at 80-85 °C for 3 h, it was evaporated to dryness.
The residue was taken up in ice-cold H2O when a pale yellow
solid formed. The solid was filtered, washed with H2O, and
then purified by flash silica gel chromatography eluting with
a gradient of 0-5% MeOH in CHCl3 to give 0.035 g (67%) of
the oxime; mp 249-251 °C. 1H NMR (DMSO-d6): δ 3.40 (br s,
2H), 4.0-4.1 (m, 2H), 7.30 (t, 1H, J ) 9.0 Hz), 7.55 (d, 2H, 9.0
Hz), 7.64 (d, 2H, J ) 9.0 Hz), 7.90 (s, 1H), 7.94 (d, 1H, J ) 9.0
Hz), 8.34 (d, 1H, J ) 9.0 Hz), 8.41 (t, 1H, J ) 6.0 Hz), 10.83
(s, 1H). HRMS calcd for C18H14N3O2Cl (M+ + H), 340.0853;
found (M+ + H), 340.0862. Anal. (C18H14N3O2Cl‚0.75CH2Cl2)
C, H, N.
1
pale pink solid; mp 285-287 °C. H NMR (DMSO-d6): δ 2.42
(s, 3H), 3.56-3.61 (m, 2H), 4.44 (br s, 2H), 7.32 (t, 1H, J ) 6.0
Hz), 7.92 (d, 1H, J ) 6.0 Hz), 8.40-8.44 (m, 3H). HRMS calcd
for C13H12N2O2 (M+), 228.0899; found (M+), 228.0890. Anal.
(C13H12N2O2) C, H, N.
7-(1-H yd r oxyim in o-et h yl)-3,4-d ih yd r o-2H -[1,4]d ia ze-
p in o[6,7,1-h i]in d ol-1-on e (33). NH2OH‚HCl (1.928 mmol,
0.134 g) was added to a solution of 32 (0.241 mmol, 0.055 g)
in pyridine (6 mL) at room temperature. The reaction mixture
was heated at 70-80 °C for 5 h. The solvent was removed,
and ice-cold H2O was added to the residue, whereupon a
precipitate formed, which was then filtered, washed with H2O,
and dried to give 0.040 g (68%) of a pale yellow solid; mp 238-
6-(4-F lu or o-p h en yl)-1-oxo-1,2,3,4-tetr a h yd r o[1,4]d ia ze-
p in o[6,7,1-h i]in d ole-7-ca r ba ld eh yd e (39). Using the pro-
cedure described for the preparation of 37, 17 was transformed
1
to 39 in 94% yield as a white solid; mp 268-270 °C. H NMR
1
240 °C. H NMR (DMSO-d6): δ 2.16 (s, 3H), 3.56 (br s, 2H),
(DMSO-d6): δ 3.52-3.54 (m, 2H), 4.19-4.22 (m, 2H), 7.40-
7.50 (m, 3H), 7.75 (d, 1H, J ) 6.0 Hz), 7.78 (d, 1H, J ) 6.0
Hz), 8.46 (d, 1H, J ) 6.0 Hz), 8.52 (t, 1H, J ) 6.0 Hz), 9.64 (s,
1H). LRMS (M+ + H) 309. HPLC Rt ) 3.522 min.
4.36 (br s, 2H), 7.19 (t, 1H, J ) 6.0 Hz), 7.77 (s, 1H), 7.87 (d,
1H, J ) 6.0 Hz), 8.33 (t, 1H, J ) 6.0 Hz), 8.38 (d, 1H, J ) 6.0
Hz), 10.67 (s, 1H). HRMS calcd for C13H13N3O2 (M+), 243.1008;
found (M+), 243.0997. Anal. (C13H13N3O2) C, H, N.
6-(4-F lu or o-p h en yl)-1-oxo-1,2,3,4-tetr a h yd r o[1,4]d ia ze-
p in o[6,7,1-h i]in d ole-7-ca r ba ld eh yd e Oxim e (40). NH2OH‚
HCl (0.325 mmol, 0.100 g) was added to a solution of 39 (0.813
mmol, 0.056 g) in pyridine (10 mL) at room temperature. The
reaction mixture was stirred at room temperature for 20 h.
Upon completion of the reaction, the solvent was removed in
vacuo. The residue was taken up in 2 N HCl and extracted
with EtOAc several times. The combined organic extracts were
dried over anhydrous MgSO4 and concentrated to give 0.097
g (92%) of a pale yellow solid, which was used without further
purification; mp 277-279 °C. 1H NMR (DMSO-d6): δ 3.50 (br
s, 2H), 4.12-4.14 (m, 2H), 7.30 (t, 1H, J ) 6.0 Hz), 7.43 (t,
2H, J ) 9.0 Hz), 7.57-7.62 (m, 2H), 7.89 (s, 1H), 7.94 (d, 1H,
J ) 9.0 Hz), 8.33 (d, 1H, J ) 6.0 Hz), 8.41 (t, 1H, J ) 6.0 Hz),
10.80 (s, 1H). HRMS calcd for C18H14N3O2F (M+), 323.1070;
found (M+), 323.1066. Anal. calcd for C18H14N3O2F‚0.3H2O: %
C, 65.76; % H, 4.48; % N, 12.78. Found: % C, 66.06; % H, 4.51;
% N, 12.32.
7-(1-H yd r oxy-1-p h en yl-m et h yl)-3,4-d ih yd r o-2H -[1,4]-
d ia zep in o[6,7,1-h i]in d ol-1-on e (34). Using the procedure
described for the preparation of 31, 3 was exposed to phenyl-
lithium yielding 74% of 34 as a yellow solid; mp 178-180 °C.
1H NMR (DMSO-d6): δ 3.51-3.52 (m, 2H), 4.28-4.29 (m, 2H),
5.70 (d, 1H, J ) 6.0 Hz), 5.96 (d, 1H, J ) 6.0 Hz), 7.05 (t, 1H,
J ) 6.0 Hz), 7.14 (s, 1H), 7.17-7.22 (m, 1H), 7.30 (t, 2H, J )
6.0 Hz), 7.45 (d, 2H, J ) 6.0 Hz), 7.72 (d, 1H, J ) 6.0 Hz),
7.79 (d, 1H, J ) 6.0 Hz), 8.24 (t, 1H, J ) 6.0 Hz). HRMS calcd
for C18H16N2O2 (M+), 292.1212; found (M+), 292.1202. Anal.
(C18H16N2O2‚0.25 H2O) C, H, N.
7-(1-P h en yl-m eth an oyl)-3,4-dih ydr o-2H-[1,4]diazepin o-
[6,7,1-h i]in d ol-1-on e (35). Using the procedure described for
the preparation of 32, o-iodooxybenzoic acid and 34 were used
to synthesize 35 in 80% yield as a pale yellow solid; mp 229-
1
230 °C. H NMR (DMSO-d6): δ 3.58-3.61 (m, 2H), 4.47 (br s,
2H), 7.40 (t, 1H, J ) 6.0 Hz), 7.52-7.65 (m, 3H), 7.79-7.82
(m, 2H), 7.98 (d, 1H, J ) 6.0 Hz), 8.08 (s, 1H), 8.44 (t, 1H, J
) 6.0 Hz), 8.51 (d, 1H, J ) 6.0 Hz). HRMS calcd for C18H14N2O2
(M+), 290.1055; found (M+), 290.1042. Anal. (C18H14N2O2) C,
H, N.
6-(4-F lu or o-p h en yl)-1-oxo-1,2,3,4-tetr a h yd r o[1,4]d ia ze-
p in o[6,7,1-h i]in d ole-7-ca r bon itr ile (41). Thiocarbonyldi-
imidazole (2.33 mmol, 0.415 g) was added to a solution of 40
(0.932 mmol, 0.301 g) in THF (70 mL) at room temperature.
The reaction mixture was stirred at room temperature for 4
h. Upon consumption of 40, the solvent was removed in vacuo.
The residue was dissolved in EtOAc and washed with 10% HCl
and then with saturated NaHCO3. The organic layer was dried
over anhydrous MgSO4 and concentrated to give a yellow oil,
which was purified by flash silica gel chromatography eluting
with a gradient of 0-3% MeOH in CHCl3 to give 0.268 g (94%)
7-(1-Hyd r oxyim in o-1-p h en yl-m eth yl)-3,4-d ih yd r o-2H-
[1,4]d ia zep in o[6,7,1-h i]in d ol-1-on e (36). Using the proce-
dure described for the preparation of 33, NH2OH‚HCl and 35
were used to synthesize 36 in 76% yield as a pale yellow solid;
mp 263-265 °C (mixture of syn and anti oximes). 1H NMR
(DMSO-d6): δ 3.51 (br s, 2H), 3.60 (br s, 2H), 4.29 (br s, 2H),
4.45 (br s, 2H), 6.97-7.04 (m, 3H), 7.24 (t, 1H, J ) 6.0 Hz),
7.34-7.46 (m, 10H), 7.82 (d, 1H, J ) 6.0 Hz), 7.89-7.93 (m,
2H), 8.31-8.36 (m, 3H), 10.74 (s, 1H), 11.37 (s, 1H). HRMS
calcd for C18H15N3O2 (M+), 305.1164; found (M+), 305.1177.
Anal. (C18H15N3O2‚0.1 H2O) C, H, N.
1
of a pale yellow solid; mp 248-250 °C. H NMR (DMSO-d6):
δ 3.52 (br s, 2H), 4.29-4.31 (m, 2H), 7.41-7.53 (m, 3H), 7.77
(d, 1H, J ) 6.0 Hz), 7.80 (d, 1H, J ) 6.0 Hz), 7.90 (d, 1H, J )
6.0 Hz), 8.01 (d, 1H, J ) 6.0 Hz), 8.55 (t, 1H, J ) 6.0 Hz).
HRMS calcd for C18H12N3OF (M+), 305.0964; found (M+),
305.0951. Anal. (C18H12N3OF‚0.1H2O) C, H, N.
6-(4-Ch lor o-p h en yl)-1-oxo-1,2,3,4-tetr a h yd r o[1,4]d ia ze-
p in o[6,7,1-h i]in d ole-7-ca r ba ld eh yd e (37). POCl3 (0.3 mL,
3.19 mmol) was slowly added to DMF (3 mL) at 0 °C. The
reaction mixture was stirred for 15 min and then was treated
with a solution of 15 (0.070 g, 0.236 mmol) in DMF (2 mL)
and warmed to room temperature for 4 h. After all solvent
was removed, the residue was taken up in H2O and made basic
(pH 12-14) using 50% aqueous NaOH whereupon solids
formed. The product was filtered, washed with water several
6-(4-F lu or o-p h en yl)-1-oxo-1,2,3,4-tetr a h yd r o[1,4]d ia ze-
p in o[6,7,1-h i]in d ole-7-ca r boxylic Acid Am id e (42). A sus-
pension of 41 (0.164 mmol, 0.050 g) in 85% H3PO4 (7 mL) was
heated at 90-100 °C for 22 h. Upon completion (as indicated
by TLC), the reaction mixture was poured into cold H2O and
extracted with EtOAc several times. The combined organic
extracts were dried over anhydrous MgSO4 and concentrated
to give a pink oil, which was purified by flash silica gel
chromatography eluting with a gradient of 0-5% MeOH in
CHCl3 to give 0.042 g (79%) of a pale yellow solid; mp 287-
1
times, and dried (0.077 g); mp 278-279 °C. H NMR (DMSO-
d6): δ 3.41-3.52 (m, 2H), 4.20-4.22 (m, 2H), 7.43 (t, 1H, J )
9.0 Hz), 7.68 (d, 2H, J ) 9.0 Hz), 7.74 (d, 2H, J ) 9.0 Hz),
8.00 (d, 1H, J ) 6.0 Hz), 8.47 (d, 1H, J ) 6.0 Hz), 8.51 (t, 1H,
J ) 6.0 Hz), 9.65 (s, 1H). HRMS calcd for C18H13N2O2Cl (M+),
324.0665; found (M+), 324.0668. Anal. (C18H13N2O2Cl‚0.25H2O)
C, H, N.
1
289 °C. H NMR (DMSO-d6): δ 3.47 (br s,2H), 3.98-4.06 (m,
2H), 6.46 (br s, 1H), 7.09 (br s, 1H), 7.28 (t, 1H, J ) 6.0 Hz),
7.38 (t, 2H, J ) 9.0 Hz), 7.56 (d, 1H, J ) 6.0 Hz), 7.60 (d, 1H,
J ) 6.0 Hz), 7.90 (d, 1H, J ) 6.0 Hz), 8.15 (d, 1H, J ) 6.0 Hz),
8.40 (t, 1H, J ) 6.0 Hz). HRMS calcd for C18H14N3O2F (M+),
323.1070; found (M+), 323.1063. Anal. (C18H14N3O2F‚0.5H2O)
C, H, N.
6-(4-Ch lor o-p h en yl)-1-oxo-1,2,3,4-tetr a h yd r o[1,4]d ia ze-
p in o[6,7,1-h i]in d ole-7-ca r ba ld eh yd e oxim e (38). NH2OH‚
HCl (0.027 g, 0.385 mmol) and NaOH (0.016 g, 0.385 mmol)
were added to a suspension of 37 (0.050 g, 0.154 mmol) in

3,4-Dihydro-2H-[1,4]diazepino[6,7,1-hi]indol-1-ones
J ournal of Medicinal Chemistry, 2004, Vol. 47, No. 22 5479
6-(4-F lu or o-p h en yl)-1-oxo-1,2,3,4-tetr a h yd r o[1,4]d ia ze-
p in o[6,7,1-h i]in d ole-7-ca r both ioic Acid Am id e (43). In an
opened sealed tube apparatus, H2S gas was bubbled into a
solution of 41 (0.5 mmol, 0.153 g) in Et3N (1 mL) and pyridine
(2.4 mL) at 0 °C for 1 h until saturated. The tube was then
carefully sealed, allowed to warm to room temperature, and
stirred at room temperature for 4 days. The tube was cooled
to 0 °C and carefully vented, and the remaining H2S was
purged with argon. The dark green solution was diluted with
EtOAc and washed with 2 N HCl and then with H2O. The
organic layer was dried over anhydrous MgSO4 and concen-
trated to give a yellow solid, which was purified by flash silica
gel chromatography eluting with a gradient of 0-3% MeOH
in CHCl3 to give 0.107 g (63%) of a yellow solid; mp 238-240
°C. 1H NMR (DMSO-d6): δ 3.47 (br s, 2H), 4.01-4.11 (m, 2H),
7.27 (t, 1H, J ) 9.0 Hz), 7.37 (t, 2H, J ) 9.0 Hz), 7.54-7.58
(m, 2H), 7.88 (d, 1H, J ) 9.0 Hz), 8.19 (d, 1H, J ) 9.0 Hz),
8.42 (t, 1H, J ) 6.0 Hz), 8.63 (br s, 1H), 9.50 (br s, 1H). HRMS
calcd for C18H14N3OSF (M+), 339.084162; found (M+), 339.0833.
Anal. (C18H14N3OSF‚0.3H2O‚0.3 MeOH) C, H, N.
7-Acetyl-6-(4-flu or o-p h en yl)-3,4-d ih yd r o-2H-[1,4]d ia ze-
p in o[6,7,1-h i]in d ol-1-on e (48). A solution of the 47 (0.246
mmol, 0.100 g), ethoxyvinyl tributyltin (0.320 mmol, 0.11 mL),
tetrakistriphenyl phosphine palladium (0.0123 mmol, 0.014
g), and ∼1.0 mg of 2,6-di-tert-butyl-4-methyl phenol in 1,4-
dioxane (20 mL) and DMF (1 mL) was heated at 90-95 °C for
20 h. After it was cooled to ambient temperature, the solvent
was evaporated to dryness and the residue was taken up in 1
N HCl and extracted with EtOAc several times. The combined
organic layers were dried over anhydrous MgSO4 and concen-
trated to give a yellow oil, which was purified by flash silica
gel chromatography eluting with a gradient of 0-3% MeOH
in CHCl3 to yield 0.049 g (64% crude) of a yellow solid. Further
purification by preparative HPLC yielded 26% of 98% pure
product using gradient solvent system of:
time (min)
H2O w/ 0.1% TFA
CH3CN w/ 0.1% TFA
0
2
22
90
90
35
10
10
65
6-(4-F lu or o-p h en yl)-1-oxo-1,2,3,4-tetr a h yd r o[1,4]d ia ze-
p in o[6,7,1-h i]in d ole-7-ca r boxim id oth ioic Acid Meth yl
Ester (44). Iodomethane (3.218 mmol, 0.2 mL) was added to
a solution of the 43 (0.354 mmol, 0.120 g) in 50 mL of THF at
room temperature and stirred for 18 h. The solvent was
removed to give a yellow solid (0.130 g), which was used
mp 275-276 °C. 1H NMR (DMSO-d6): δ 1.86 (s, 3H),
3.45-3.52 (m, 2H), 3.96-3.98 (m, 2H), 7.37 (t, 1H, J ) 6.0
Hz), 7.45 (t, 2H, J ) 9.0 Hz) 7.64 (d, 1H, J ) 6.0 Hz), 7.67
(d, 1H, J ) 6.0 Hz), 7.96 (d, 1H, J ) 6.0 Hz), 8.42 (t, 1H,
1
J
C
) 6.0 Hz), 8.55 (d, 1H, J ) 6.0 Hz). HRMS calcd for
without further purification. H NMR (DMSO-d6): δ 2.63 (s,
19H15N2O2F (M+), 322.1117; found (M+), 322.1131. HPLC Rt
3H), 3.51 (br s, 2H), 4.01-4.05 (m, 2H), 7.42-7.53 (m, 3H),
7.62 (d, 1H, J ) 6.0 Hz), 7.65 (d, 1H, J ) 6.0 Hz), 8.02 (d, 1H,
J ) 3.0 Hz), 8.05 (d, 1H, J ) 3.0 Hz), 8.57 (t, 1H, J ) 6.0 Hz).
) 10.608 min.
6-(4-F lu or o-p h en yl)-7-((E)-2-h yd r oxy-1-m eth yl-vin yl)-
3,4-d ih yd r o-2H-[1,4]d ia zep in o[6,7,1-h i]in d ol-1-on e (49).
NH2OH‚HCl (0.93 mmol, 0.066 g) was added to a solution of
the 48 (0.124 mmol, 0.040 g) in 4 mL of pyridine at room
temperature. The reaction mixture was stirred for 24 h
whereupon the reaction mixture was evaporated to dryness.
The residue was taken up in 2 N HCl and extracted with
EtOAc several times. The combined organic layers were dried
over anhydrous MgSO4 and concentrated to give a pale yellow
solid, which was purified by flash silica gel chromatography
eluting with a gradient of 0-3% MeOH in CHCl3 to give 0.025
g (60%) of a white solid; mp 248-250 °C. 1H NMR (DMSO-
d6): δ 1.70 (s, 3H), 3.49 (br s, 2H), 4.07-4.09 (m, 2H), 7.21 (t,
1H, J ) 6.0 Hz), 7.37 (t, 2H, J ) 9.0 Hz), 7.51 (d, 1H, J ) 6.0
Hz), 7.55 (d, 1H, J ) 6.0 Hz), 7.89 (d, 1H, J ) 6.0 Hz), 8.09 (d,
1H, J ) 6.0 Hz), 8.37 (t, 1H, J ) 6.0 Hz), 10 93 (s, 1H). HRMS
calcd for C19H16N3O2F (M+), 337.1226; found (M+), 337.1230.
Anal. for (C19H16N3O2F‚0.1H2O) C, H, N.
6-(4-Flu or o-ph en yl)-N-h ydr oxy-1-oxo-1,2,3,4-tetr ah ydr o-
[1,4]d ia zep in o[6,7,1-h i]in d ole-7-ca r b oxa m id in e
(45).
NH2OH‚HCl (0.852 mmol, 0.059 g) was added to a solution of
the 44 (0.142 mmol, 0.05 g) in 5 mL of pyridine at room
temperature and the mixture was stirred for 15 min. The
solvent was removed to give an oil, which was purified by flash
silica gel chromatography eluting with a gradient of 0-5%
MeOH in CHCl3 initially, followed by 2-10% MeOH/NH3 in
CHCl3 to give 0.025 g (52%) of a pale yellow solid; mp 257-
259 °C. 1H NMR (DMSO-d6): δ 3.45-3.47 (m, 2H), 4.10-4.12
(m, 2H), 5.41 (br s, 2H), 7.23 (t, 1H, J ) 6.0 Hz), 7.34 (t, 2H,
J ) 9.0 Hz), 7.57 (d, 1H, J ) 6.0 Hz), 7.59 (d, 1H, J ) 6.0 Hz),
7.88 (d, 1H, J ) 9.0 Hz), 7.93 (d, 1H, J ) 9.0 Hz), 8.39 (br s,
1H), 9.33 (br s, 1H). HRMS calcd for C18H15N4O2F (M+),
338.1179; found (M+), 338.1182. Anal. (C18H15N4O2F‚0.5 H2O)
C, H, N.
6-(4-F lu or o-p h en yl)-N-a m in o-1-oxo-1,2,3,4-tetr a h yd r o-
[1,4]d ia zep in o[6,7,1-h i]in d ole-7-ca r boxa m id in e Hyd r o-
ch lor id e (46). Anhydrous hydrazine (2.92 mmol, 0.092 mL)
was added to a solution of the 44 (0.139 mmol, 0.049 g) in 25
mL of acetonitrile at room temperature. The reaction mixture
was stirred for 48 h, and the solvent was removed to give an
oil, which was purified by flash silica gel chromatography
eluting with a gradient of 0-10% MeOH in CHCl3 initially,
followed by 2-10% MeOH/NH3 in CHCl3 yielding 0.028 g (64%)
of a white crystalline solid. This solid was dissolved in MeOH
saturated with HCl gas and stirred at room temperature for
30 min. Diethyl ether was added to the solution, and the
solvent was then evaporated to give an orange solid (9 mg);
mp 272-274 °C. 1H NMR (DMSO-d6): δ 3.58 (br s, 2H), 4.22-
4.23 (m, 2H), 5.18 (br s, 2H), 7.37-7.46 (m, 3H), 7.54-7.58
(m, 2H), 7.82 (d, 1H, J ) 6.0 Hz), 8.00 (d, 1H, J ) 6.0 Hz),
8.55 (t, 1H, J ) 6.0 Hz), 8.79 (br s, 1H), 9.08 (br s, 1H), 10.60
(br s, 1H). HRMS calcd for C18H16N5OF (M+), 337.1339; found
(M+), 337.1326. Anal. (C18H16N5OF‚1.0H2O‚4.5HCl) C, H, N.
7-((E)-3-Dim eth yla m in o-a cr yloyl)-6-(4-flu or o-p h en yl)-
3,4-d ih yd r o-2H-[1,4]d ia zep in o[6,7,1-h i]in d ol-1-on e (50).
N,N′-Dimethylformamide dimethyl acetal (13.88 mmol, 2 mL)
was added to a solution of 48 (0.217 mmol, 0.070 g) in DMF (1
mL) at room temperature. The reaction mixture was stirred
at 110-120 °C for 18 h. Upon completion of the reaction as
indicated by TLC, the solvent was removed in vacuo to give
0.101 g (quantitative yield) of an orange solid, which was used
1
without further purification. H NMR (DMSO-d6): δ 3.30 (s,
6H), 3.50 (br s, 2H), 3.98-4.05 (m, 2H), 4.61 (d, 1H, J ) 12.0
Hz), 7.26 (t, 1H, J ) 6.0 Hz), 7.35-7.43 (m, 3H), 7.54-7.58
(m, 2H), 7.89 (d, 1H, J ) 6.0 Hz), 8.37-8.43 (m, 2H). LC mass
(M+ + H) 378.
6-(4-F lu or o-p h en yl)-7-(2H -p yr a zol-3-yl)-3,4-d ih yd r o-
2H-[1,4]diazepin o[6,7,1-h i]in dol-1-on e (51). Hydrazine mono-
hydrate (5.14 mmol, 0.26 mL) was added to a solution of 50
(0.257 mmol, 0.097 g) in 10 mL of THF at room temperature.
The reaction mixture was stirred at room temperature for 42
h and then evaporated to dryness. The residue was taken up
in 2 N HCl and extracted with EtOAc several times. The
combined organic layers were dried over anhydrous MgSO4
and concentrated to give a yellow oil, which was purified by
flash silica gel chromatography eluting with a gradient of
0-3% MeOH in CHCl3 to give 0.020 g (23%) of a yellow solid;
mp 173-175 °C. 1H NMR (DMSO-d6): δ 3.45-3.52 (m, 2H),
4.03-4.08 (m, 2H), 5.64 (br s, 1H), 7.23 (t, 1H, J ) 6.0 Hz),
7.32 (t, 2H, J ) 9.0 Hz), 7.38-7.55 (m, 3H), 7.88 (d, 1H, J )
6-(4-F lu or o-p h en yl)-7-iod o-3,4-d ih yd r o-2H-[1,4]d ia ze-
p in o[6,7,1-h i]in d ol-1-on e (47). Using the procedure de-
scribed for the preparation of 26, 17 was converted with I2
and KOH to 47 in 78% yield as a pale yellow solid; mp 283-
1
285 °C. H NMR (DMSO-d6): δ 3.48 (br s, 2H), 4.15-4.18 (m,
2H), 7.29 (t, 1H, J ) 6.0 Hz), 7.41 (t, 2H, J ) 9.0 Hz), 7.58-
7.64 (m, 3H), 7.94 (d, 1H, J ) 6.0 Hz), 8.41 (t, 1H, J ) 6.0
Hz). LRMS (M+ + H) 407.

5480 J ournal of Medicinal Chemistry, 2004, Vol. 47, No. 22
6.0 Hz), 8.36-8.43 (m, 2H), 12.67(br s, 1H). HRMS calcd for
Tikhe et al.
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C
20H15N4OF (M+), 346.1221; found (M+), 346.1225. Anal. for
(C20H15N4OF‚1.0MeOH) C, H, N.
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