Naphthamides as novel and potent vascular endothelial growth factor receptor tyrosine kinase inhibitors: Design, synthesis, and evaluation

Article abstract of DOI:10.1021/jm701097z

A series of naphthyl-based compounds were synthesized as potential inhibitors of vascular endothelial growth factor (VEGF) receptors. Investigations of structure-activity relationships led to the identification of a series of naphthamides that are potent inhibitors of the VEGF receptor tyrosine kinase family. Numerous analogues demonstrated low nanomolar inhibition of VEGF-dependent human umbilical vein endothelial cell (HUVEC) proliferation, and of these several compounds possessed favorable pharmacokinetic (PK) profiles. In particular, compound 48 demonstrated significant antitumor efficacy against established HT29 human colon adenocarcinoma xenografts implanted in athymic mice. A full account of the preparation, structure-activity relationships, pharmacokinetic properties, and pharmacology of analogues within this series is presented.

Full text of DOI:10.1021/jm701097z

J. Med. Chem. 2008, 51, 1649–1667
1649
Naphthamides as Novel and Potent Vascular Endothelial Growth Factor Receptor Tyrosine
Kinase Inhibitors: Design, Synthesis, and Evaluation¶
Jean-Christophe Harmange,*,†,∆ Matthew M. Weiss,*,† Julie Germain,† Anthony J. Polverino,‡ George Borg,† James Bready,‡
Danlin Chen,‡ Deborah Choquette,† Angela Coxon,‡ Tom DeMelfi,‡ Lucian DiPietro,† Nicholas Doerr,‡ Juan Estrada,‡
Julie Flynn,# Russell F. Graceffa,† Shawn P. Harriman,# Stephen Kaufman,| Daniel S. La,† Alexander Long,§
Matthew W. Martin,† Sesha Neervannan,×,∞ Vinod F. Patel,† Michele Potashman,† Kelly Regal,# Phillip M. Roveto,†
Michael L. Schrag,# Charlie Starnes,‡ Andrew Tasker,† Yohannes Teffera,# Ling Wang,‡ Ryan D. White,†
Douglas A. Whittington,§ and Roger Zanon×
Department of Medicinal Chemistry, Department of Molecular Structure, and Department of Pharmacokinetics and Drug Metabolism, Amgen
Inc., One Kendall Square, Building 1000, Cambridge, Massachusetts 02139, and Department of Oncology Research, Department of Toxicology,
and Department of Pharmaceutics, Amgen Inc., One Amgen Center DriVe, Thousand Oaks, California 91320
ReceiVed September 4, 2007
A series of naphthyl-based compounds were synthesized as potential inhibitors of vascular endothelial growth
factor (VEGF) receptors. Investigations of structure–activity relationships led to the identification of a series
of naphthamides that are potent inhibitors of the VEGF receptor tyrosine kinase family. Numerous analogues
demonstrated low nanomolar inhibition of VEGF-dependent human umbilical vein endothelial cell (HUVEC)
proliferation, and of these several compounds possessed favorable pharmacokinetic (PK) profiles. In particular,
compound 48 demonstrated significant antitumor efficacy against established HT29 human colon adeno-
carcinoma xenografts implanted in athymic mice. A full account of the preparation, structure–activity
relationships, pharmacokinetic properties, and pharmacology of analogues within this series is presented.
Angiogenesis, the formation of new blood vessels from
existing vasculature, is an important pathway for normal
embryogenesis, growth, and tissue repair.1,2 It is also involved
in a number of pathological processes, including inflammation,3
rheumatoid arthritis,4 ocular neovascularization,5 psoriasis,6
tumor growth,7 and metastasis.8 Vascular endothelial growth
factor (VEGFa) and its receptor tyrosine kinases VEGFR-2 or
kinase insert domain receptor (KDR) and VEGFR-1 are key
regulators of angiogenesis.9 The increased understanding of the
molecular mechanisms involved in the VEGF signaling pathway
has enabled the development of agents that can interfere with
this process. Moreover, the concept of blocking the growth of
a solid tumor by suppressing its blood supply via the inhibition
of the VEGF pathway is now well established.7,10 Several
successful strategies for the inhibition of angiogenesis have been
effectively demonstrated in preclinical and clinical settings.
These approaches include VEGF soluble decoy receptors,11
antibodies directed against VEGF,12 and small molecules that
inhibit KDR.13,14 Bevacizumab, a recombinant humanized
monoclonal antibody directed against VEGF, has now been
approved for first or second line treatment of patients with
metastatic carcinoma of the colon or rectum and for patients
with advanced non-squamous non-small-cell lung cancer.15,16
In addition, two small-molecule inhibitors of KDR, sunitinib
(1)17,18 and sorafenib (2),19,20 have been approved for the
treatment of advanced renal cell carcinoma (Figure 1). We
previously reported the discovery of AMG 706 (N-(3,3-
dimethyl-2,3-dihydro-1H-indol-6-yl)-2-(pyridin-4-ylmethylami-
no)pyridine-3-carboxamide, motesanib diphosphate, compound
3), a potent inhibitor of VEGF receptors 1, 2, and 3 (VEG-
FR1–3).21 This molecule is being evaluated in the clinic for its
ability to inhibit angiogenesis and lymphangiogenesis and is
also under investigation for its potential direct antitumor activity
by targeting platelet-derived growth factor receptor (PDGFR)
and stem cell factor receptor (c-Kit) signaling.
¶
The PDB accession codes for cocrystals of compounds 4, 5, and 48 in
the KDR ATP-binding pocket are 2QU6, 3BE2, and 3B8Q, respectively.
* To whom correspondence should be addressed. For J-C. H.: phone,
617-444-5044; fax, 617-577-9511; e-mail, harmange@amgen.com. For
M.M.W.: phone, 617-444-5188; fax, 617-621-3908; e-mail, mmweiss@
amgen.com.
†
Department of Medicinal Chemistry.
∆
Dedicated to Professor Yoshito Kishi on the occasion of his 70th
Recently, we reported the discovery of 2-aminobenzoxazoles
(Figure 2, 4) as a novel class of potent KDR inhibitors.22
Separately, we also disclosed the discovery of a novel series of
pyridylpyrimidine derivatives as Tie-2 kinase inhibitors (Figure
2, 5).23 Interestingly, in this latter series several compounds were
identified that displayed potent inhibition of KDR (i.e., 5, IC50
KDR ) 2 nM). In an effort to utilize this scaffold as a starting
point to discover a new series of KDR inhibitors, an X-ray
cocrystal structure of 5 bound to KDR was obtained. As
illustrated by the cocrystal structures of 4 and 5 complexed with
KDR (Figure 2), the binding mode of these inhibitors to KDR
is similar (PDB accession codes 2QU6 and 3BE2, respectively).
Of particular interest was the observation that both of these
inhibitors force the protein to adopt a “DFG-out” conformation.
This conformational change in turn enables the inhibitors to
birthday.
‡
Department of Oncology Research.
Department of Pharmacokinetics and Drug Metabolism.
Department of Pathology.
Department of Molecular Structure.
Department of Pharmaceutics.
Present Address: Allergan, 2525 Dupont Drive, Irvine, CA 92623.
#
|
§
×
∞
a Abbreviations: VEGF, vascular endothelial growth factor; KDR, kinase
domain region; HUVEC, human umbilical vein endothelial cells; PDGF,
platelet-derived growth factor; HTRF, homogeneous time-resolved fluo-
rescence; bFGF, basic fibroblast growth factor; FBS, fetal bovine serum;
MRT, mean retention time; DIPEA, diisopropylethyl amine; HATU, O-(7-
azabenzotriazol-1-yl)-N,N,N′,N′-tetramethyluronium hexafluorophosphate;
TBTU, 2-(1H-benzotriazole-1-yl)-1,1,3,3-tetramethyluronium tetrafluorobo-
rate; EDCI, N-ethyl-N′-(3-dimethylaminopropyl)carbodiimide hydrochloride;
NHDF, normal human dermal fibroblast; DPPP, 1,3-bis(diphenylphospino)
propane; HOAt, 1-hydroxy-7-aza-benztriazole.
10.1021/jm701097z CCC: $40.75
2008 American Chemical Society
Published on Web 03/07/2008

1650 Journal of Medicinal Chemistry, 2008, Vol. 51, No. 6
Harmange et al.
Figure 1. Examples of small-molecule KDR inhibitors undergoing clinical trials.
Figure 2. Crystallographic analysis of compounds 4 (left) and 5 (right) in the ATP-binding pocket of KDR. Hydrogen bonds are shown between
the inhibitors and KDR (dotted lines).
project into the extended hydrophobic pocket, a lipophilic pocket
that cannot be accessed when the enzyme is in the “DFG-in”
conformation.
engage Glu 885 and Asp 1046 but could also project a lipophilic
moiety into the extended hydrophobic pocket. It was anticipated
that the resulting naphthamide (i.e., 6) could afford a starting
point for a novel series of potent and selective inhibitors of
KDR with improved properties over those observed for the
parent aminobenzoxazoles (4)24 and pyridylpyrimidines (5).25
Herein, we describe the synthesis, structure–activity relationships
(SAR), and pharmacological characterization of naphthamides,
a new series of potent KDR inhibitors.26
Examination of an overlay of 4 and 5 revealed a number of
similarities that could potentially be exploited (Figure 3). Good
overlap was observed between the pyridine of 4 and the
pyrimidine of 5, with both groups binding to the hinge region
of KDR. The p-chloroaniline of 4 and the m-trifluoromethyla-
niline of 5 occupied similar areas in the extended lipophilic
pocket. In addition, the overlay of the 2-aminobenzoxazole of
4 and the 3-aminobenzamide of 5, both of which occupy the
hydrophobic pocket, suggested that a naphthyl or structurally
similar unit could serve as a scaffold from which to build a
novel series of KDR inhibitors. In order to maintain the critical
interactions with the protein, we hypothesized that the resulting
hybrid structure should retain the pyridine moiety from 4 to
bind to the hinge region of the kinase while also preserving the
amide functionality from 5 which not only would serve to
Chemistry
Our strategy for the construction of the naphthamides
described in this paper is outlined in the retrosynthetic analysis
shown in Scheme 1.26 Naphthamides 7 and related compounds
were prepared via activation of the carboxylic acid 8 and
subsequent reaction with the desired amine R1NH2. Carboxylic
acid 8 was in turn accessed via coupling of 6-hydroxynaphthoic
acid (10) or a related derivative (i.e., 9) with the desired

Naphthamides as Inhibitors
Journal of Medicinal Chemistry, 2008, Vol. 51, No. 6 1651
Figure 3. Overlay of 2-aminobenzoxazole 4 and pyridylpyrimidine 5 (left) and the emergence of a novel naphthamide-based scaffold (right).
Scheme 1. Retrosynthetic Analysis of Naphthamides
Scheme 2. Synthesis of Naphthoic Acid and Related Bicyclic Compoundsa
a Reagents: (a) SOCl2, MeOH, room temp; (b) Selectfluor, MeCN, 85 °C; (c) NaOH, H2O, MeOH, reflux; (d) CO, 50 psi, MeOH, Pd(OAc)2, DPPP, Et3N,
DMF, 70 °C; (e) BBr3, CH2Cl2, 0 °C to room temp; (f) SOCl2; Et3N, 2-bromobenzylamine; H2SO4; (g) Pd(OAc)2, DPPP, Et3N, CO, 30 psi, DMF, MeOH,
100 °C; (h) Tf2O, DIPEA, CH2Cl2, -78 °C; (i) Pd2(dba)3, K3PO4, DME, 2-(dicyclohexylphosphino)biphenyl, benzophenone imine; (j) HCl.
heterocycle. This concise modular route allowed for the efficient
construction of the desired naphthamides and rapid exploration
of the SAR.
The 6-hydroxynaphthoic acid derivatives and related bicyclic
units were either obtained from commercial sources (10) or
prepared (12, 15, 18, and 21) as outlined in Scheme 2. 5-Fluoro-
6-hydroxynaphthoic acid (12) was synthesized in three steps
from 6-hydroxynaphthoic acid (10) starting with the conversion
of the carboxylic acid to the corresponding methyl ester.27
Subsequent fluorination with 1-chloromethyl-4-fluoro-1,4-
diazoniabicyclo[2.2.2]octane bis-tetrafluoroborate proceeded in
a regioselective fashion to afford 11 in modest yield. Hydrolysis
of the methyl ester yielded the desired naphthoic acid 12 in
nearly quantitative yield. 7-Hydroxyquinoline-4-carboxylic acid

1652 Journal of Medicinal Chemistry, 2008, Vol. 51, No. 6
Scheme 3. Synthesis of 4-Chloroquinolinesa
Harmange et al.
ether was achieved utilizing SNAr chemistry (Scheme 4,
reactions 2 and 3). The latter compounds (34a-c), which
encompass an aminopyridine or aminopyrimidine moiety, were
accessed in two steps from the appropriate dichloropyridine or
pyrimidine by treatment with cesium carbonate followed by
reaction with methylamine.
The construction of inhibitors wherein the central naphthyl
ring was modified is illustrated in Scheme 5. Preparation of the
5-fluoro-1-naphthoic acid derivative 36a and the 7-quinoline-
4-carboxylic acid 36c were achieved using the SNAr conditions
described above. The preparation of isoquinoline 36b required
the use of the more reactive 4-fluoro-6,7-dimethoxyquinoline
(27) because low yields were obtained when the less reactive
4-chloro-6,7-dimethoxyquinoline (35) was employed. In the
event, coupling of isoquinoline 18 and 27 in the presence of
cesium carbonate with microwave irradiation afforded the
corresponding biaryl ether which after in situ hydrolysis of the
methyl ester provided acid 36c (Scheme 5, reaction 1).
Construction of the biarylamine core (37a,b) occurred most
smoothly when acidic conditions were employed. Thus, 6-ami-
nonaphthoyl derivative 21 was heated with 6,7-dimethoxyquino-
line (35) and trifluoroacetic acid in isopropanol to afford the
corresponding biarylamine (Scheme 5, reaction 2). The derived
amine could be advanced to aniline 37a by hydrolysis of the
methyl ester. Alternatively, alkylation of the derived aniline by
exposure to sodium hydride and methyl iodide followed by
hydrolysis furnished 37b.
a Reagents: (a) Meldrum’s acid, i-PrOH, 80 °C; (b) Ph2O, 240 °C; (c)
SOCl2, DMF, reflux; (d) NH4OH, 110 °C; (e) n-Bu4PHF2, microwave
heating, 120 °C.
(15) was accessed from 4-chloro-7-methoxyquinoline (13) in
two steps. Palladium-mediated carbonylation of 13 yielded 14
which following exposure to BBr3 gave rise to acid 15.
Isoquinoline 18 was prepared from diethylacetal glyoxalic acid
(16) via coupling with 2-bromobenzylamine followed by in situ
cyclization to afford 8-bromo-3-hydroxyisoquinoline (17) in
good yield. Subsequent palladium-mediated carbonylation yielded
the desired methyl ester 18. Finally, aminonapthyl 21 was
derived from methyl 6-hydroxynaphthoate (19) via triflate 20,
which underwent a palladium-mediated amination with ben-
zophenone immine. Hydrolysis of the derived immine provided
aniline 21.
The heterocycles employed as linker binder elements in our
naphthamides were obtained from commercial sources, prepared
as previously described,28 or prepared by the methods outlined
in Scheme 3 (25, 27). Quinoline 25 was synthesized in four
steps starting with the condensation of methyl 4-amino-2-
methoxybenzoate (22) with Meldrum’s acid in isopropanol to
afford enamide 23. Subsequent heating of 23 at 240 °C triggered
intramolecular cyclization to give quinolone 24, which upon
chlorination of the ketone and aminolysis of the methyl ester
led to the desired chloroquinoline 25. 4-Fluoro-6,7-dimethox-
yquinoline (27) was prepared from commercially available
4-chloroquinoline (26) by nucleophilic aromatic substitution
using tetrabutylphosphonium fluoride hydrofluoride under mi-
crowave (MW) irradiation.
The various building blocks could be combined to form the
desired naphthoic acid intermediates or related compounds as
shown in Schemes 4 and 5. Scheme 4 illustrates the synthesis
of inhibitors centered around an unmodified naphthyl core.
Biaryl ethers 29a-e were obtained by nucleophilic aromatic
substitution (SNAr) of the corresponding heteroaryl chloride
28 with 6-hydroxynaphthoic acid (10) in the presence of cesium
carbonate at 140 °C (Scheme 4, reaction 1). The construction
of 3-fluoroquinoline derivative 29f was achieved by the pal-
ladium-mediated coupling of 6-hydroxynaphthoic acid (10) and
6,7-dimethoxy-3-fluoro-4-chloroquinoline because coupling of
these two partners under standard nucleophilic aromatic sub-
stitution conditions led to unselective addition at the 3 and 4
positions of the quinoline.28 Pyridine and pyrimidine containing
compounds 31a-d and 34a-c were obtained in a manner
similar to that described above wherein formation of the aryl
Scheme 6 outlines the completion of the synthesis of the
naphthamides and related compounds 39. Amide bond construc-
tion was accomplished either by treatment of the appropriate
acid (i.e., 38) with the desired amine in the presence of an
activating agent (i.e., HATU, TBTU, or EDCI) or by conversion
of the acid to the corresponding acid chloride and subsequent
reaction with the desired amine.
Results and Discussion
Structure–Activity Relationships (SAR). The in vitro
enzymatic activity of all compounds was assessed using a
homogeneous time-resolved fluorescence (HTRF) assay with
the catalytic domain of KDR. Potency at the cellular level was
evaluated by determining the inhibition of human umbilical vein
endothelial cell (HUVEC) proliferation induced by VEGF, an
assay that is carried out in the presence of 10% fetal bovine
serum (FBS). As a cellular selectivity screen used to assess
inhibition of basic fibroblast growth factor receptor (bFGFR)
and downstream kinases that participate in the angiogenic
signaling cascade, inhibition of HUVEC proliferation driven by
basic fibroblast growth factor (bFGF) was also measured. While
bFGF is known to be an important growth factor involved in
angiogenesis, the use of a bFGF-driven HUVEC proliferation
assay as a selectivity screen would allow for a more direct
correlation between VEGFR-2 inhibition and the observed
pharmacology.
To test our original hypothesis, compound 6 was evaluated
for enzyme and cell activity. Naphthamide 6 inhibited KDR
with an IC50 of 3 nM and the VEGF driven proliferation of
HUVECs with an IC50 of 210 nM. This enzymatic and cellular
potency was combined with an encouraging selectivity at the
cellular level (bFGF-HUVEC IC50 > 1100 nM). This initial
promising result led us to explore variations of the pyridyl
moiety binding to the hinge region while maintaining the N-4-
chlorophenylnaphthamide functionality. The enzyme potencies
as well as cellular activities are summarized in Table 1.
Within the N-4-chlorophenylnaphthamide series, the enzyme
tolerated the incorporation of a variety of monocyclic (6, 40–44)

Naphthamides as Inhibitors
Journal of Medicinal Chemistry, 2008, Vol. 51, No. 6 1653
Scheme 4. Preparation of Naphthoic Acid and Related Intermediatesa
a Reagents: (a) Cs2CO3, DMSO, 140 °C; (b) 5 mol % Pd(OAc)2, 10 mol % t-Bu-XPhos, K3PO4, DMF, 100 °C; (c) Cs2CO3, DMSO, 110 °C; (d) MeNH2,
235 °C; (e) MeNH2, THF, 0 °C to room temp.
Scheme 5. Preparation of Naphthoic Acid and Related Intermediatesa
a Reagents: (a) Cs2CO3, DMSO, 140 °C; (b) Cs2CO3, DMF, microwave heating, 120 °C; (c) TFA, i-PrOH, 90 °C; (d) 6 N NaOH, MeOH, room temp;
(e) NaH, MeI, DMF, 0 °C to room temp; 6 N NaOH, MeOH, room temp.
Scheme 6. Preparation of Naphthamides and Related
examined that displayed substantially reduced enzymatic activ-
ity. While pyridine 40 and 2-substituted pyridines 6 and 41
displayed potent inhibition at the enzyme level, these compounds
exhibited a 12- to 70-fold enzyme to cell shift. The 2-substituted
and 5-substituted aminomethylpyrimidine derivatives 43 and 44
were slightly less potent at the enzymatic level but exhibited a
smaller enzyme to cell shift than the corresponding pyridine
(41). The fusion of a second ring obtained by closing the
6-aminomethylpyrimidine 44 to the corresponding 7H-pyr-
rolo[2,3-d]pyrimidine provided 45. This modification led to an
inhibitor with similar inhibition of KDR but improved cellular
potency compared to the 6-aminomethylpyrimidine 44, 37 nM
vs 106 nM. Furthermore, 6,6-fused bicycles 46–48 and 50, 51
afforded single digit nanomolar inhibitors of KDR. Quinoline
derivatives bearing a 6 and/or 7 substituent (s) (47, 48, and 50)
provided compounds that inhibited VEGF-induced proliferation
of HUVEC with IC50 < 10 nM with a high degree of selectivity
(100-fold) over bFGF-induced proliferation. Other modifications
included the 3-F quinoline 49, which resulted in a 40-fold loss
in activity compared with 48, and quinazoline 51, which proved
to be slightly more potent than 48 at the cellular level while
maintaining selectivity.
Compoundsa
a Reagents: (a) amine, HATU, DIPEA, DMF; or amine, TBTU, DIPEA,
DMF; or amine, HOAt, EDCI, DIPEA, DMF; (b) (COCl)2, cat. DMF,
CH2Cl2; amine; or thionyl chloride; amine.
and bicyclic (45–51) heterocycles (Table 1). Removal of the
carboxamide group led to a 6-fold reduction in enzyme potency
(6 vs 40), presumably because of the loss of the hydrogen-bond
interaction between the NH of the carboxamide and the carbonyl
of Cys919 in the hinge region of KDR. The inclusion of a
heterocycle with a suitably placed hydrogen bond donor to
interact with the hinge region of KDR provided improved
potency. This trend is exemplified by 41 and 46, wherein it is
the C8 proton of the quinoline ring in 46 that is engaged with
the carbonyl of Cys919.29 Pyrimidine 42 was the only analogue
Having established the 6,7-dimethoxyquinoline as one of the
more favorable heterocycles to bind to the hinge region of KDR,
we turned our attention toward modifications of the arylamide

1654 Journal of Medicinal Chemistry, 2008, Vol. 51, No. 6
Harmange et al.
Table 1. Structure–Activity Relationship (SAR): Variation of the
Table 2. SAR: Variations of the Naphthamide Moietya
Nitrogen Containing Heterocycle Binding the Hinge Regiona
HUVEC IC50 (nM)b
compd
R1
KDR IC50 (nM) VEGF
bFGF
48
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
4-Cl-Ph
Ph
2-F-Ph
3-F-Ph
4-F-Ph
3-Cl-Ph
4-Me-Ph
3-CF3-Ph
4-CF3-Ph
4-t-Bu-Ph
2,4-Cl-Ph
3,5-Cl-Ph
3-CF3-4-Cl-Ph
2-pyridyl
3-pyridyl
4-pyridyl
2-thiazolyl
3-isoxazole
5-methyl-3- isoxazolyl
3-methyl-5-isoxazolyl
5-tert-butyl-3-isoxazolyl
cyclopropyl
1-methylcyclopropyl
cyclobutyl
0.5
0.2
2
0.6
1
0.3
0.5
0.5
0.5
0.7
2
0.3
1
0.8
0.8
2
0.3
0.2
0.6
1
0.8
0.6
8
0.8
7
3
2
5.1
2
34
16
63
14
28
247
2
2
2
2
0.4
6
7
68
1
70
7
7
>1140
577
>1140
ND
305
ND
548
205
228
944
>1140
742
228
286
1100
>1140
605
ND
250
>1140
190
167
ND
>1140
>1140
>1140
>1140
15
3
9
1.3
5
cyclopentyl
propyl
isopropyl
7
4
a See Experimental Section for the description of the assays. IC50 values
were averaged values determined by at least two independent experiments.
b Human umbilical vein endothelial cells. ND: not determined.
increasing the size and placement of substituents on the
phenylnaphthamide had very little impact on enzyme inhibition.
However, cellular potency was more sensitive to modifications
in this region as is observed by the range of cellular activity
displayed by 53–63 (2-247 nM). While small lipophilic groups
such as chlorine (48, 56) and methyl (57) did not significantly
impact the enzyme to cell shift (2- to 16-fold), larger and/or
more lipophilic groups, such as tert-butyl (60) and trifluoro-
methyl (58, 59) led to decreased cell potency, despite promising
enzyme activity. With the exception of 58–60 and 62, all of
the phenyl substituted naphthamides demonstrated >75 fold
selectivity at the cellular level.
The preparation of a more diverse group of naphthamides
was next pursued, and several heteroaromatic rings (64–71),
cycloalkyl groups (72–75), and small alkyl groups (76, 77) were
incorporated into the inhibitors. The heteroaryl derivatives 64–70
exhibited enzyme and cellular activities comparable to the
substituted phenyl compounds. It is noteworthy that pyridyl
derivatives 64–66 were tolerated in the extended hydrophobic
region of the enzyme. While isoxazole 69 exhibited favorable
cellular activity, erosion of selectivity at the cellular level was
observed; however, 3-methylisoxazolyl derivative 70 demon-
strated potent and selective inhibition at the cellular level.
Cycloalkylamides 72–75 were also well tolerated, though some
loss of potency was observed with methylcyclopropyl 73.
Interestingly, the cyclopropyl derivative 72 achieved remarkable
enzyme and cellular potency.30 Small alkyl groups such as
a IC50 values were averaged values determined by at least two indepen-
dent experiments. b Human umbilical vein endothelial cells. ND: not
determined.
occupying the extended hydrophobic pocket of the enzyme. A
number of alterations were made to explore the effects on
enzyme inhibition, cellular activity, and selectivity; the results
of these studies are detailed in Table 2. Removal of the p-Cl
substituent from 48 provided phenylnaphthamide 52, which
retained its potency against KDR. The incorporation of sub-
stituents on the phenyl ring (53–63) did not significantly impact
the enzyme–inhibitory activity (0.3–2 nM). In this regard,

Naphthamides as Inhibitors
Journal of Medicinal Chemistry, 2008, Vol. 51, No. 6 1655
Table 3. SAR: Variations of the Naphthyl Regiona
Table 5. Pharmacokinetic Parameters for Naphthamides 48, 64–66, 70,
and 78
48
RLM ((µL/min)/mg)a 50
HLM ((µL/min)/mg)a 30
64
90
80
13
>50
65
90
90
2
66
80
30
0.1
0.7
70
40
40
40
78
30
30
Cyp 3A4 IC50 (µM)
Cyp 2D6 IC50 (µM)
>50
>50
>50
17
>50 >50
Rat Pharmacokinetics
Cl ((L/h)/kg)
Vss (L/kg)
t1/2 (h)
MRT (h)
Cmax (ng/mL)
0.2b
7.3b
24b
0.4d
3.1d
6.1d
7.8d
200e
0.9d
1.3d
1.1d
1.4d
5710f
0.6d
1.4d
1.8d
2.5d
1690f
1.3g 0.1h
2.7g 2.4h
2.4g 17h
2.1g 22h
ND 610i
31b
420c
AUC(0–24) (ng·h/mL) 5250c 1240e 27100f 10980f ND 6010i
F (%)
21c
45e
100f
62f
ND 50i
a Rat microsomal clearance (RLM). Human microsomal clearance
(HLM). Compound concentration ) 1 µM. Microsomal protein concentra-
tion ) 1 mg/mL. b iv, 2 mpk, DMSO. c po, 5 mg/kg, OraPlus. d iv, 1 mg/
kg, DMSO. e po, 2 mg/kg, OraPlus. f po, 10 mg/kg, OraPlus. g iv, 0.5 mg/
kg, DMSO; h iv, 0.25 mg/kg, DMSO. i 2 mg/kg, 1% Tween-80, 2% HPMC,
97% water adjusted pH 2.
Table 6. Pharmacokinetic Parameters for 48 (Monomethansulfonic Salt)
in Mouse, Dog, and Cyno
species
Cl ((L/h)/kg)
Vss (L/kg)
t1/2 (h)
MRT (h)
F (%)
mouse
dog
cyno
0.2a
0.1c
0.2c
4.8a
6.7c
4.3c
17a
48c
56c
23a
66c
22c
24b
72b
62b
a iv, 3 mg/kg, propylene glycol. b po, 10 mg/kg, OraPlus. c iv, 1 mg/kg,
propylene glycol.
a IC50 values were averaged values determined by at least two indepen-
dent experiments. b Human umbilical vein endothelial cells.
the corresponding naphthyl derivatives. Isoquinoline 80 dis-
played reduced enzymatic and cellular potency and yet did not
inhibit bFGF-stimulated HUVEC proliferation. These findings
suggest that the lipophilic pocket of KDR is more sensitive and
less tolerant of variation when compared to the extended
lipophilic pocket.
Table 4. SAR: Variations of the Linker Atoma
As summarized in Table 4, a brief examination of modifica-
tions to the tether that serves to link the naphthyl ring and the
heterocycle binding the hinge region revealed that alteration to
this tether has a dramatic effect on KDR inhibition. Replacement
of the ether linkage in 48 with the amine tether in 81 resulted
in less than 2-fold decrease in cell potency but an almost 10-
fold loss in selectivity. Furthermore, methylation of this amine
provided 82, which displayed a further 140-fold reduction of
activity on KDR. The disparity between 81 and 82 may arise
from the methyl group on the amine disrupting the coplanarity
of the quinoline and naphthyl rings by generating a steric clash
between the N-methyl group and the C5 hydrogen on the
quinoline.
HUVEC IC50 (nM)b
compd
X
KDR IC50 (nM)
VEGF
bFGF
48
81
82
O
NH
NMe
0.5
8
>1400
8
14
ND
>1100
115
ND
a IC50 values were averaged values determined by at least two indepen-
dent experiments. b Human umbilical vein endothelial cells. ND: not
determined.
Pharmacokinetic Profiles. After the features necessary for
potent and selective KDR inhibitors were established, the
pharmacokinetic profiles of several compounds were evaluated
(Table 5). Compounds 48, 64–66, 70, and 78 all exhibited low
to moderate intrinsic clearance in rat (RLM) and human (HLM)
liver microsomes. Given the propensity of nitrogen containing
heterocycles to bind to the heme of cytochrome P450, this set
of compounds was screened against the 3A4 and 2D6 isoforms.
With the exception of the pyridyl-containing compounds
(64–66), no significant levels of Cyp inhibition were observed.
However, the 4-pyridyl derivative 66 strongly inhibited both
3A4 and 2D6 Cyp isoenzymes with estimated IC50 values of
100 and 700 nM, respectively. The position of the nitrogen in
the ring had a dramatic effect on the inhibitory activity at the
3A4 and 2D6 isoforms, and the 2-pyridyl derivative 64 had a
favorable profile with IC50 values above 10 µM.
n-propyl and isopropyl were also well tolerated, as demonstrated
by the enzyme and cellular potency of compounds 76 and 77.
Cognizant of the inherent metabolic activation liabilities
potentially associated with the naphthyl residue, modifications
of the central bicyclic aromatic core were explored (Table 3).
Inclusion of a fluorine at the 5-position of the naphthoyl moiety
afforded 78, a potent KDR inhibitor with impressive cellular
potency and selectivity. An alternative approach involved the
incorporation of a heteroatom into the naphthyl ring and led to
quinoline 79 and isoquinoline 80. While quinoline 79 was 40-
fold less potent than 48 at the enzymatic level, it exhibited no
enzyme to cell shift and retained cellular potency. The selectivity
of 79 at the cellular level was decreased in comparison with

1656 Journal of Medicinal Chemistry, 2008, Vol. 51, No. 6
Harmange et al.
Figure 4. Selectivity profile of compound 48.
Table 7. Enzyme and Cellular Selectivity Profile for Compound 48
enzyme
KDR
c-FMS
PDGFR-ꢀ
FGFR-2
Lck
IC50 (nM)
cell
functional readouta IC50 (nM)
0.5
20
<1
55
38
18
HUVEC
Balb/c3T3
NHDF
HUVEC
T cell
proliferationb
proliferationc
proliferationd
proliferatione
proliferationf
histone H3
phosphorylation
Erk
8
25
25
>1140
>20000
1100
Aurora B
Hela cell
b-Raf V600E
40
A375
>1000
(melanoma) phosphorylation
a Stimulation. b VEGF. c CSF-1. d PDGF. e FGF. f Anti-CD3.
Figure 7. Effect of 48 on VEGF-induced vascular permeability in mice.
HEK 293 cells transfected with murine VEGF or vector were mixed
with Matrigel and injected subcutaneously into CD-1 nu/nu mice. A
single dose of compound was given and vascular permeability in the
skin overlying the Matrigel plug assessed 6 h later. Data represent the
mean ( standard error (n ) 5 animals per group): (/) P e 0.0001.
Figure 5. X-ray crystal structure of compound 48 bound to KDR.
Figure 8. Inhibition of VEGF-induced angiogenesis in the rat corneal
model by 48. Angiogenesis was induced by implanting a VEGF-soaked
or BSA-soaked (control) nylon disk into the corneal stroma. The number
of blood vessels intersecting the midpoint between the disk and the
limbus was measured. Data represent the mean ( standard error (n )
8 animals per group): (/) P e 0.001.
reflection of the low clearance (0.1–0.2 (L/h)/kg) and moderate
to high Vss (2.4–7.3 L/kg) exhibited by these two compounds.
To assess the potential for metabolic activation of the
naphthamide moiety of 48, 14C labeled 48 was synthesized and
incubated with human liver microsomes.32,33 No significant
levels of covalent binding were observed (<100 (pM/mg)/h).
On the basis of its impressive in vitro profile and rat
pharmacokinetics, an expanded PK profile of compound 48
across species was obtained. As illustrated in Table 6, compound
48 demonstrated low clearance and acceptable oral bioavail-
ability in mouse, dog, and monkey (cynomolgous). Analogous
to the pharmacokinetics that compound 48 exhibited in rats,
the low clearance and high volume of distribution were observed
across all species and in turn gave rise to extended MRTs (22–66
h). The measured plasma protein binding of compound 48 in
rat, mouse, dog, and human was 98.0%, 98.6%, 97.4%, and
99.3%, respectively.
Figure 6. Inhibition of murine KDR (Flk-1) phosphorylation in lungs
by compound 48 (n ) 3 animals per group): (/) P e 0.0001.
Consistent with their low in vitro metabolic turnover in RLM,
the naphthamides examined were cleared at low to moderate
rates after dosing to male Sprague–Dawley rats. The highest
rates of clearance were observed for 3-pyridyl 65 and 3-methyl-
5-isoxazolyl 70 at 0.9 and 1.3 (L/h)/kg, respectively. All of the
compounds examined demonstrated acceptable bioavailability
and suitable half-lives.31 The extended mean retention time
(MRT) exhibited by compounds 48 and 78 (24 and 17 h) is a

Naphthamides as Inhibitors
Journal of Medicinal Chemistry, 2008, Vol. 51, No. 6 1657
Pharmacodynamic Profile. The in vivo inhibitory activity
of compound 48 for the VEGF RTK was assessed by measuring
the inhibition of murine KDR (Flk-1) phosphorylation in mouse
lungs. In addition, the in vivo pharmacological properties of
compound 48 were evaluated in a VEGF-induced vascular
permeability assay, a VEGF-induced rat corneal angiogenesis
model, and a tumor xenograft disease model. Results of these
in vivo studies are described below.
Murine KDR (Flk-1) Lung Phosphorylation Assay. Balb/c
female mice were dosed orally with compound 48 at 3, 10, and
30 mpk. Two hours after dosing with 48, 3 µg of murine VEGF
was injected intravenously, and after 5 min the mice were
sacrificed and the lungs were immediately dissected. Levels of
phosphorylated Flk-1 were subsequently determined by Delphia
assay. As shown in Figure 6, a dose dependent inhibition of
Flk-1 phosphorylation was observed with significant inhibition
seen at all doses tested (P < 0.0001). At the three doses
examined, terminal plasma levels of compound 48 were
measured to be 0.16, 0.49, and 1.5 µM.
Figure 9. Antitumor activity upon treatment with 48 or vehicle in an
HT29 colon cancer xenograft in CD-1 nu/nu mice (n ) 10 animals per
group): (/) P e 0.0001.
Matrigel Plug Assay. Vascular permeability was induced in
female CD-1 nu/nu mice by subcutaneous implantation of a
Matrigel plug containing HEK293 cells overexpressing recom-
binant murine VEGF. After 22 h, a single dose of compound
48 was administered orally at 10, 30, and 100 mg/kg. After an
additional 6 h, an iv injection of 0.1 mL 1% Evans blue dye
was administered. Vascular permeability was quantified by the
amount of extravasated dye in a 1 cm2 piece of skin overlying
the plug. A dose dependent inhibition of vascular permeability
was observed with statistically significant effects being seen at
doses of 30 and 100 mg/kg (Figure 7). At the active doses of
30 and 100 mg/kg, the plasma concentrations of 48 at t ) 6 h
were 4.0 and 10.3 µM, respectively.
Rat Corneal Assay. Compound 48 was also evaluated in
the rat corneal angiogenesis model (Figure 8). Female Spra-
gue–Dawley rats were implanted with a VEGF- or BSA-soaked
disk into the corneal stroma. Compound 48 was administered
once daily (QD) for 7 days, at which point the corneas were
photographed and the number of blood vessels was measured.
A dose dependent decrease in the number of blood vessels was
observed with an estimated ED50 of 0.1 mg/kg. Pharmacokinetic
analysis determined the corresponding AUC and Cmax to be 1.3
µM·h and 0.2 µM, respectively.
Tumor Xenograft Model. The antitumor activity of 48 was
measured in a human colon adenocarcinoma (HT29) xenograft
model in female CD-1 nu/nu mice (Figure 9). Mice bearing
tumors staged at approximately the same size (300 mm3) were
dosed orally with vehicle or 48 once a day for 14 days. The
tumor volume was determined twice per week by caliper
measurements and recorded along with body weights as an
indicator of gross toxicity. Significant inhibition of tumor growth
was observed at doses of 3, 10, and 30 mg/kg, and significant
tumor regression was observed at doses of 10 and 30 mg/kg
after 7 and 10 days, respectively (Table 8). These strong
pharmacological effects were observed without any significant
weight loss.
Table 8. In Vivo Antitumor Activity of 48 against Established Human
HT29 Colon Cancer Xenografts Implanted Subcutaneously in CD-1
Nu/Nu Micea
dose (mg/kg)b
effect
AUC0–24 (µM·h)
Cmax (µM)
3
10
30
74% inhibition
regression
regression
6.2
24.1
48.4
0.5
2.2
3.9
a n ) 10 animals per group. b The freebase was dosed po as a suspension
in OraPlus.
Selectivity Profile. Prior to an in vivo pharmacological
evaluation of compound 48, the kinase selectivity profile was
examined. As shown by the heat map in Figure 4, 48 was a
pan VEGFR inhibitor displaying an IC50 value of 0.5 nM for
VEGFR-1 (Flt-1) and 2.0 nM for VEGFR-3 (Flt-4). Compound
48 exhibited selectivity over a variety of tyrosine and serine/
threonine kinases (∼500-fold: IGF-1R, CDK1, CDK5, JNK,
BTK, etc.).34 More importantly, compound 48 was selective
against numerous receptor tyrosine kinases implicated in an-
giogenic processes. Toward this end, compound 48 was highly
selective against FGFR1, c-Met, and Tie-2 while it showed
modest activity against PDGFR-ꢀ. Consistent with the kinome,
48 strongly inhibited the VEGF-related kinases PDGFR-ꢀ, c-Kit,
and c-Fms. The implication of the potency of 48 against other
kinases was further examined at the cellular level (Table 7). In
addition to VEGF driven HUVEC proliferation, 48 inhibited
the proliferation of Balb/c3T3 cells stimulated with CSF-1 and
of NHDF cells stimulated with PDGF, in agreement with its
inhibitory activity on c-FMS and PDGFR, respectively. How-
ever, inhibition of FGFR-2, Lck, Aurora B (Aurora 1), and b-Raf
did not translate into any significant cellular activity.
X-Ray Structural Analysis. In an effort to confirm the
binding elements responsible for the observed potency and to
substantiate our original design hypothesis, an X-ray cocrystal
structure of KDR with naphthamide 48 was obtained. As
illustrated in Figure 5, 48 bound to the ATP binding site of
KDR and forced the protein to adopt a “DFG-out” conformation,
enabling the p-chlorophenyl ring to penetrate into the extended
hydrophobic pocket (PDB accession code 3B8Q). A highly
conserved hydrogen-bond interaction between the backbone
amide-NH of Cys919 and the nitrogen of the quinoline ring
anchors the inhibitor to the hinge region of the binding pocket
and orients the naphthyl ring into the hydrophobic pocket. The
carbonyl and NH groups of the amide form critical hydrogen
bonds with the backbone NH of Asp1046 and the side chain of
Glu885, respectively.
Conclusions
Guided by the X-ray structures of two inhibitors bound to
the VEGF receptor tyrosine kinase, a novel series of potent
inhibitors, naphthamides, were designed and evaluated. Through
modification of the different units of this scaffold, we identified
several potent and selective compounds. Among them, 48
demonstrated good pharmacokinetics across species and robust
pharmacological activity that included in vivo inhibition of

1658 Journal of Medicinal Chemistry, 2008, Vol. 51, No. 6
Harmange et al.
was purged with carbon monoxide for 10 min and then placed under
50 psi of CO. The reaction vessel was sealed and heated at 70 °C.
After heating for 6 h, additional Pd(OAc)2 (134 mg, 0.60 mmol)
and 1,3-bis(diphenylphosphino)propane (370 mg, 0.90 mmol) were
added. The mixture was again purged with carbon monoxide for
10 min, placed under 50 psi of CO, then sealed and heated at 70
°C for 16 h. The mixture was allowed to cool to room temperature
and was passed through a plug of Celite before being concentrated
and purified by silica gel chromatography to provide the title
angiogenesis and regression of established HT29 tumors in
female CD-1 nu/nu mice. Further optimization of this series of
KDR inhibitors toward the selection of a clinical candidate will
be reported in due course.
Experimental Section
Unless otherwise noted, all materials were obtained from
commercial suppliers and used without further purification. Anhy-
drous solvents were purchased from Aldrich packaged under
nitrogen in Sure/Seal bottles. Purity of final compounds was
measured using Agilent 1100 series high-performance liquid
chromatography (HPLC) systems with UV detection at 254 nm
(system A consisting of Agilent Zorbax Eclipse XDB-C8 4.6 mm
× 150 mm, 5 µm, 5–100% CH3CN in H2O with 0.1% TFA for 15
min at 1.5 mL/min; system B consisting of Phenomenex Gemini,
3.0 mm × 50 mm, 5 µm, 5–95% CH3CN in H2O with 0.1% FA
for 3 min at 1.5 mL/min); system C consisting of Waters Xterra
4.6 mm × 150 mm, 3.5 µm, 5–95% CH3CN in H2O with 0.1%
1
compound (400 mg, 59%) as a white solid. H NMR (400 MHz,
DMSO-d6) δ ppm 8.97 (d, J ) 4.44 Hz, 1 H), 8.52 (d, J ) 9.60
Hz, 1 H), 7.77 (d, J ) 4.45 Hz, 1 H), 7.50 (s, 1 H), 7.39 (t, J )
9.70 Hz, 1 H), 3.97 (s, 3 H), 3.95 (s, 3 H). MS, m/z (C12H11NO3):
calcd, 217.1; found, 218.0 (MH).
7-Hydroxyquinoline-4-carboxylic Acid (15). To a solution of
methyl 7-methoxyquinoline-4-carboxylate (14, 378 mg, 1.74 mmol)
in 25 mL of CH2Cl2 at 0 °C was added boron tribromide (1.0 M in
CH2Cl2, 9.0 mL). The mixture was allowed to warm to room
temperature over 3 h and maintained at ambient temperature for
an additional 48 h. The reaction was quenched with ice (50 g),
which resulted in the formation of a yellow solid. The derived solid
was filtered and washed with ether to provide the title compound
(233 mg, 60%) as a yellow solid. 1H NMR (400 MHz, DMSO-d6)
δ ppm 9.10 (d, J ) 4.51 Hz, 1 H), 8.50 (d, J ) 9.50 Hz, 1 H), 7.60
(d, J ) 4.54 Hz, 1 H), 7.55 (s, 1 H), 7.37 (t, J ) 9.72 Hz, 2 H).
MS, m/z (C10H7NO3): calcd, 189.1; found, 190.1 (MH).
8-Bromoisoquinolin-3-ol (17). To a solution of 2,2-diethoxy-
acetic acid (16.8 g, 113.5 mmol) in 90 mL of ether was added
sulfuryl dichloride (8.259 mL, 113.5 mmol). After being stirred at
10 °C for 10 min, the mixture was heated to reflux for 30 min and
then cooled to room temperature. The derived acid chloride was
used immediately in the next step. To a solution of the derived
acid chloride (18.91 g, 113.5 mmol) in Et2O (90 mL) was added a
solution of (2-bromophenyl)methanamine (21.11 g, 113.5 mmol)
in 60 mL of toluene and 35 mL of pyridine. The mixture was heated
to reflux for 30 min before being cooled to room temperature and
partitioned between toluene (100 mL) and ice–water (250 mL). The
layers were separated, and the aqueous layer was extracted with
toluene (3 × 100 mL). The combined organic extracts were washed
with 2% HCl and water and concentrated in vacuo. The resulting
residue was purified by silica gel chromatography to provide N-(2-
bromobenzyl)-2,2-diethoxyacetamide (22.8) as a light-yellow oil.
MS, m/z (C13H18BrNO3): calcd, 315.0; found, 316.2 (MH).
To concentrated sulfuric acid (100 g) at 10 °C was added the
derived N-(2-bromobenzyl)-2,2-diethoxyacetamide (22.8 g, 72.1
mmol). The resulting solution was allowed to warm to room
temperature and was stirred for 24 h. The mixture was poured into
ice–water (250 mL) and filtered, and the filtrate was neutralized
with 33% ammonium hydroxide. The resulting solid was filtered
to provide the title compound (15.9 g, 62%) as a bright-yellow
solid. MS, m/z (C9H6BrNO): calcd, 223.0; found, 224.1 (MH).
Methyl 3-Hydroxyisoquinoline-8-carboxylate (18). To a pres-
sure vessel was added 8-bromoisoquinolin-3-ol (17, 5.00 g, 22.3
mmol), 1,3-bis(diphenylphosphino)propane (552 mg, 1.34 mmol),
and Pd(OAc)2 (200 mg, 0.893 mmol) followed by 15 mL of DMF,
25 mL of methanol, and triethylamine (7.76 mL, 55.8 mmol). The
vessel was purged three times with carbon monoxide, pressurized
to 30 psi, and heated to 100 °C for 12 h. The mixture was
concentrated in vacuo, and the residue was partitioned between ethyl
acetate (50 mL) and water (50 mL). The organic layer was separated
and washed successively with water and brine. Purification by silica
gel chromatography provided the title compound (0.960 g, 21%
yield) as a yellow solid. MS, m/z (C11H9NO3): calcd, 203.1; found,
204.1 (MH).
1
TFA for 12 min at 1.0 mL/min. H NMR spectra were recorded
on a Bruker AV-4000 (400 MHz) spectrometer at ambient tem-
perature. Chemical shifts are reported in ppm from the solvent
resonance (DMSO-d6, 2.50 ppm; CDCl3, 7.27 ppm). Data are
reported as follows: chemical shift, multiplicity (s ) singlet, d )
doublet, t ) triplet, q ) quartet, br ) broad, m ) multiplet),
coupling constants, and number of protons. Low-resolution mass
spectral (MS) data were determined on an Agilent 1100 series
LCMS with UV detection at 254 nm and a low-resonance
electrospray mode (ESI). High-resolution mass spectra were
obtained on a high-resonance electrospray time-of-flight mass
spectrometer. Combustion analysis was performed by Galbraith
Laboratories, Inc., Knoxville, TN, and were within 0.4% of
calculated mass unless otherwise noted.
Methyl 5-Fluoro-6-hydroxy-1-naphthoate (11). To a solution
of 6-hydroxy-1-naphthoic acid (10, 10.00 g, 53.1 mmol) in 500
mL of methanol at 0 °C was added thionyl chloride (6.28 g, 53.1
mmol). The mixture was allowed to warm to ambient temperature
and was stirred for 12 h before being concentrated to provide the
corresponding methyl ester (10.53 g, 98%) as a colorless oil. To a
solution of the derived ester (7.00 g, 34.6 mmol) in 60 mL of
CH3CN was added Selectfluor (12.3 g, 34.6 mmol). The mixture
was heated at 85 °C for 24 h before being allowed to cool to room
temperature. The mixture was diluted with ethyl acetate (500 mL)
and sequentially washed with water (250 mL) and brine. Drying
over sodium sulfate followed by filtration and concentration
provided a residue that was purified by silica gel chromatography
(100% CH2Cl2) to provide the title compound (3.81 g, 50%) as a
1
yellow solid. H NMR (400 MHz, DMSO-d6) δ ppm 10.32 (s, 1
H), 8.40 (d, J ) 8.88 Hz, 1 H), 8.14 (d, J ) 8.44 Hz, 1 H), 7.96
(d, J ) 8.43 Hz, 1 H), 7.59 (t, J ) 8.43 Hz, 1 H), 7.37 (t, J ) 9.88
Hz, 1 H), 3.90 (s, 3 H). MS, m/z (C12H9FO3): calcd, 220.1; found,
221.0 (MH).
Methyl-5-fluoro-6-hydroxy-1-naphthoic Acid (12). To a solu-
tion of methyl 5-fluoro-6-hydroxy-1-naphthoate (11, 3.70 g, 16.8
mmol) in 100 mL of methanol was added a solution of NaOH (50.4
g, 1.26 mol) in 30 mL of water. After heating at 80 °C for 20 h,
the mixture was allowed to cool to room temperature and was
poured into 200 mL of 1 N HCl, resulting in the formation of a
slightly yellow precipitate. HCl (6 N) was slowly added until the
formation of no additional precipitate was observed. The solid was
filtered and washed with water to provide the title compound (3.20
1
g, 92%) as a slightly yellow solid. H NMR (400 MHz, DMSO-
d6) δ ppm 10.27 (s, 1 H), 8.51 (d, J ) 9.63 Hz, 1 H), 8.10 (d, J )
7.63 Hz, 1 H), 7.96 (d, J ) 7.18 Hz, 1 H), 7.57 (t, J ) 8.03 Hz, 1
H), 7.35 (t, J ) 9.18 Hz, 1 H). MS, m/z (C12H7FO3): calcd, 206.1;
found, 207.3 (MH).
Methyl 7-Methoxyquinoline-4-carboxylate (14). A 25 mL
sealable tube was charged with 4-chloro-7-methoxyquinoline (13,
0.60 g, 3.10 mmol), Pd(OAc)2 (67 mg, 0.30 mmol), 1,3-bis(diphe-
nylphosphino)propane (185 mg, 0.45 mmol), triethylamine (0.87
mL, 6.20 mmol), MeOH (1 mL), and DMF (5 mL). The mixture
Methyl 6-(Trifluoromethylsulfonyloxy)-1-naphthoate (20). To
a solution of methyl 6-hydroxy-1-naphthoate (19, 1.50 g, 7.40
mmol) in 100 mL of CH2Cl2 at -78 °C was added DIPEA (3.80
mL, 22.0 mmol) and triflic anhydride (1.55 mL, 9.25 mmol).
Stirring was continued at this temperature for 1 h at which point
the mixture was poured into saturated NH4Cl (50 mL). The layers
were separated, and the aqueous layer was extracted with CH2Cl2

Naphthamides as Inhibitors
Journal of Medicinal Chemistry, 2008, Vol. 51, No. 6 1659
(3 × 50 mL). The combined organic layers were washed with brine,
dried over sodium sulfate, filtered, and concentrated. Purification
by silica gel chromatography provided the title compound (2.21 g,
89%) as a light-brown solid. MS, m/z (C13H9F3O5S): calcd, 334.0;
found, 335.1 (MH).
over Na2SO4, concentrated in vacuo, and purified by reverse-phase
chromatography to provide the title compound (0.032 g, 17%) as
a white solid. MS, m/z (C11H10FNO2): calcd, 207.1; found, 208.1
(MH).
6-(2-(Methylcarbamoyl)pyridin-4-yloxy)-1-naphthoic Acid (31c).
To a solution of 6-hydroxynaphthoic acid (10, 1.50 g, 7.98 mmol)
in 20 mL of DMSO was added cesium carbonate (7.80 g, 24.0
mmol). After the mixture was stirred for 5 min, 4-chloro-N-
methylpicolinamide (1.36 g, 7.98 mmol) was added and the resulting
slurry was heated to 140 °C for 16 h. The mixture was allowed to
cool to room temperature and was purified by silica gel chroma-
tography (0–10% CH3OH in CH2Cl2) to provide a pink oil. The
derived oil was taken up in 400 mL of ethyl acetate and was washed
with water (3 × 150 mL). The organics were washed with brine,
dried over sodium sulfate, and filtered. Concentration to 10% of
the original volume provided a purple mixture that was placed in
the refrigerator overnight. The resulting precipitate was filtered and
washed with ethyl acetate (2 × 50 mL) to provide the title
Methyl 6-Amino-1-naphthoate (21). In a 250 mL sealable tube
were added Pd2(dba)3 (55 mg, 0.06 mmol), (biphenyl)dicyclohexyl-
phosphine (84 mg, 0.23 mmol), potassium phosphate (1.90 g, 8.90
mmol), and dimethoxyethane (10 mL). The mixture was degassed
for 10 min at which point methyl 6-(trifluoromethylsulfonyloxy)-
1-naphthoate (20, 2.00 g, 6.0 mmol) and benzophenone imine (1.25
mL, 7.5 mmol) were added. The flask was sealed and heated at 90
°C for 8 h. The mixture was allowed to cool to room temperature,
and 4 mL of 2 N HCl was added. After the mixture was stirred for
30 min, 50 mL of ethyl acetate was added and the pH was adjusted
to 10 with 6 N NaOH. The layers were separated, and the aqueous
layer was extracted with ethyl acetate (3 × 50 mL). The combined
organic layers were washed with brine, dried over sodium sulfate,
filtered, and concentrated. The derived residue was purified by silica
gel chromatography (0–30% ethyl acetate in hexanes) to provide
21 (1.15 g, 95%) as a light-brown oil that was used immediately
in the next step. MS, m/z (C12H11N2O2): calcd, 201.1; found, 202.1
(MH).
Methyl 4-((2,2-Dimethyl-4,6-dioxo-1,3-dioxan-5-ylidene)methyl-
amino)-2-methoxybenzoate (23). A suspension of methyl 4-amino-
2-methoxybenzoate (22, 10.00 g, 55.19 mmol) in 200 mL of
isopropanol was heated at 50 °C for 10 min at which point
5-(methoxymethylene)-2,2-dimethyl-1,3-dioxane-4,6-dione (9.64 g,
51.78 mmol) was added. The resulting suspension was heated at
80 °C for 1 h before being cooled to room temperature. The solid
was filtered, washed well with ether, and dried in vacuo to provide
the title compound (23, 15.25 g, 82%) as a brown solid that was
immediately used in the next step.
Methyl 7-Methoxy-4-oxo-1,4-dihydroquinoline-6-carboxylate
(24). A suspension of methyl 4-((2,2-dimethyl-4,6-dioxo-1,3-dioxan-
5-ylidene)methylamino)-2-methoxybenzoate (23, 15.00 g, 53.96
mmol) in 135 mL of diphenyl ether was heated at 240 °C for 8 h.
The mixture was cooled to room temperature and filtered. The
resulting brown solid was washed with ether and dried in vacuo to
provide methyl 7-methoxy-4-oxo-1,4-dihydroquinoline-6-carboxy-
late (24, 9.60 g, 76%) as a brown solid that was used without further
purification.
4-Chloro-7-methoxyquinoline-6-carboxamide (25). Methyl
7-methoxy-4-oxo-1,4-dihydroquinoline-6-carboxylate (24, 5.00 g,
21.46 mmol) was added to 20 mL of thionyl chloride. Three drops
of DMF were added, and the mixture was heated at 125 °C for
3 h. The mixture was cooled to room temperature, and the solvent
was removed in vacuo. The derived solid was taken up in CH2Cl2
(250 mL) and poured into saturated NaHCO3 (500 mL). The layers
were separated, and the aqueous layer was extracted with CH2Cl2
(250 mL). The combined organic layers were washed with brine,
dried over sodium sulfate, filtered, and concentrated to provide a
tan solid. Trituration of the solid with ether/hexanes provided methyl
4-chloro-7-methoxyquinoline-6-carboxylate (4.70 g, 87%) as a tan
solid. The derived ester (1.00 g, 3.97 mmol) was added to
ammonium hydroxide (20 mL), and the mixture was heated at 110
°C for 8 h before being cooled to room temperature. The mixture
was filtered and the resulting solid was washed sequentially with
water and ether to provide the title compound (852 mg, 91%) as a
tan solid. 1H NMR (400 MHz, DMSO-d6) δ ppm 8.82 (d, J )
4.80 Hz, 1 H), 8.49 (s, 1 H), 7.90 (br s, 1 H), 7.80 (br s, 1 H), 7.65
(d, J ) 4.80 Hz, 1 H), 7.59 (s, 1 H), 4.03 (s, 3 H). MS, m/z
(C11H9ClN2O2): calcd, 236.0; found, 237.1 (MH).
1
compound (1.75 g, 68%) as a slightly pink solid. H NMR (400
MHz, DMSO-d6) δ ppm 13.29 (s, 1 H), 9.03 (d, J ) 9.35 Hz, 1
H), 8.80 (d, J ) 4.93 Hz, 1 H), 8.56 (d, J ) 5.56 Hz, 1 H),
8.14–8.22 (m, 2 H), 7.89 (d, J ) 2.53 Hz, 1 H), 7.62–7.70 (m, 1
H), 7.55 (dd, J ) 9.35, 2.53 Hz, 1 H), 7.48 (d, J ) 2.65 Hz, 1 H),
7.26 (dd, J ) 5.56, 2.53 Hz, 1 H), 2.79 (d, J ) 4.80 Hz, 3 H). MS,
m/z (C18H14N2O4): calcd, 322.1; found, 323.1 (MH).
6-(6,7-Dimethoxyquinolin-4-yloxy)-1-naphthoic Acid (29a).
The title compound was prepared from 6-hydroxy-1-naphthoic acid
(10) using a method analogous to the preparation of compound
1
31c. Yield: 24.2 g, 85%. H NMR (400 MHz, DMSO-d6) δ ppm
13.29 (s, 1 H), 9.05 (d, J ) 9.35 Hz, 1 H), 8.56 (d, J ) 5.43 Hz,
1 H), 8.13–8.23 (m, 2 H), 7.95 (d, J ) 2.53 Hz, 1 H), 7.62–7.70
(m, 2 H), 7.61 (s, 1 H), 7.48 (s, 1 H), 6.67 (d, J ) 5.56 Hz, 1 H),
3.99 (s, 3 H), 3.97 (s, 3 H). MS, m/z (C22H17NO5): calcd, 375.1;
found, 376.3 (MH).
6-(Quinolin-4-yloxy)-1-naphthoic Acid (29b). The title com-
pound was prepared from 6-hydroxy-1-naphthoic acid (10) using
a method analogous to the preparation of compound 31c. Yield:
10.4 g, 87%. 1H NMR (400 MHz, DMSO-d6) δ ppm 9.03 (d, J )
9.17 Hz, 1 H), 8.70 (d, J ) 5.13 Hz, 1 H), 8.35 (d, J ) 8.43 Hz,
1 H), 8.13–8.16 (m, 2 H), 8.05 (d, J ) 8.04 Hz, 1 H), 7.91 (d, J )
2.19 Hz, 1 H), 7.84 (t, J ) 7.33 Hz, 1 H), 7.60–7.69 (m, 3 H),
6.72 (d, J ) 5.13 Hz, 1 H). MS, m/z (C20H13NO3): calcd, 315.3;
found, 316.3 (MH).
6-(7-Methoxyquinolin-4-yloxy)-1-naphthoic Acid (29c). The
title compound was prepared from 6-hydroxy-1-naphthoic acid (10)
using a method analogous to the preparation of compound 31c.
Yield: 807 mg, 82%. 1H NMR (400 MHz, DMSO-d6) δ ppm 9.00
(d, J ) 8.72 Hz, 1 H), 8.61 (d, J ) 4.13 Hz, 1 H), 8.22 (d, J )
9.10 Hz, 1 H), 8.15 (d, J ) 4.85 Hz, 1 H), 7.88 (s, 1 H), 7.48–7.52
(m, 3 H), 7.42 (s, 1 H), 7.29 (d, J ) 9.10 Hz, 1 H), 6.58 (d, J )
5.20 Hz, 1 H), 3.93 (s, 3 H). MS, m/z (C21H15NO4): calcd, 345.1;
found, 346.3 (MH).
6-(6,7-Dimethoxyquinazolin-4-yloxy)-1-naphthoic Acid (29d).
The title compound was prepared from 6-hydroxy-1-naphthoic acid
(10) using a method analogous to the preparation of compound
31c. Yield: 900 mg, 68%. 1H NMR (400 MHz, DMSO-d6) δ ppm
9.06 (d, J ) 9.17 Hz, 1 H), 8.51 (s, 1 H), 7.63–7.68 (m, 2 H), 7.68
(d, J ) 7.29 Hz, 1 H), 7.41 (s, 1 H), 7.38–7.40 (m, 2 H), 7.33 (d,
J ) 9.18 Hz, 1 H), 3.98 (s, 6 H). MS, m/z (C21H16N2O5): calcd,
376.1; found, 377.3 (MH).
6-(6-Carbamoyl-7-methoxyquinolin-4-yloxy)-1-naphthoic Acid
(29e). The title compound was prepared from 6-hydroxy-1-
naphthoic acid (10) using a method analogous to the preparation
of compound 31c. Yield: 623 mg, 46%. 1H NMR (400 MHz,
DMSO-d6) δ ppm 9.07 (d, J ) 9.35 Hz, 1 H), 8.70–8.78 (m, 2 H),
8.20 (d, J ) 7.58 Hz, 2 H), 7.99 (d, J ) 2.40 Hz, 1 H), 7.93 (br s,
1 H), 7.80 (br s, 1 H), 7.63–7.71 (m, 2 H), 7.60 (s, 1 H), 6.71 (d,
J ) 5.43 Hz, 1 H), 4.07 (s, 3 H). MS, m/z (C22H16N2O5): calcd,
388.1; found, 389.1 (MH).
4-Fluoro-6,7-dimethoxyquinoline (27). A mixture of 4-chloro-
6,7-dimethoxyquinoline (26, 0.200 g, 0.89 mmol) and tetrabu-
tylphosphonium fluoride hydrofluoride (1.9 g, 6.3 mmol) was heated
to 120 °C in a resealable tube. After 1 h, additional tetrabutylphos-
phonium fluoride hydrofluoride (0.95 g, 3.1 mmol) was added and
the solution was heated at 120 °C for an additional 48 h. The
solution was cooled to room temperature, diluted with ethyl acetate,
and washed with water and brine. The organic fraction was dried

1660 Journal of Medicinal Chemistry, 2008, Vol. 51, No. 6
Harmange et al.
6-(3-Fluoro-6,7-dimethoxyquinolin-4-yloxy)-1-naphthoic Acid
(29f). A resealable tube was charged with 4-chloro-3-fluoro-6,7-
dimethoxyquinoline (0.610 g, 2.52 mmol), 6-hydroxy-1-naphthoic
acid (10, 0.474 g, 2.52 mmol), palladium acetate (0.023 g, 0.101
mmol), 2-di-tert-butylphosphino-2′,4′,6′-triisopropyl-1,1′-biphenyl
(0.086 g, 0.202 mmol), potassium phosphate (2.14 g, 10.08 mmol),
and DMF (13 mL). The system was flushed with argon, and the
tube was sealed. The mixture was stirred at 100 °C for 19 h and
then cooled to room temperature. Water (13 mL) was added, and
the pH was adjusted to 6–7 with aqueous 6 N HCl. The resulting
precipitate was filtered, washed with water, and then purified by
column chromatography on silica gel to afford the title compound
(0.301 g, 30%) as an off-white solid. 1H NMR (400 MHz, DMSO-
d6) δ ppm 8.97 (d, J ) 9.7 Hz, 1 H), 8.85 (s, 1 H), 7.89–8.08 (m,
2 H), 7.48–7.63 (m, 3 H), 7.41 (d, J ) 3.2 Hz, 1 H), 7.26 (s, 1 H),
3.96 (s, 3 H), 3.81 (s, 3 H). MS, m/z (C22H16FNO5): calcd, 393.1;
found, 394.0 (MH).
for 8 h. Concentration and purification by silica gel chromatography
provided 34c (517 mg, 52%) as a tan solid. H NMR (400 MHz,
1
DMSO-d6) δ ppm 8.89 (d, J ) 9.16 Hz, 1 H), 8.20 (m, 1 H), 8.12
(t, J ) 8.06 Hz, 2 H), 7.82 (s, 1 H), 7.59 (t, J ) 7.70 Hz, 1 H),
7.49 (s, 1 H), 6.95 (s, 1 H), 6.21 (s, 1 H), 3.32 (s, 3 H). MS, m/z
(C16H13N3O3): calcd, 295.1; found, 296.1 (MH).
6-(6,7-Dimethoxyquinolin-4-yloxy)-5-fluoro-1-naphthoic Acid
(36a). The title compound was prepared from 5-fluoro-6-hydroxy-
1-naphthoic acid (12) using a method analogous to the preparation
of compound 31c. Yield: 2.06 g, 56%. 1H NMR (400 MHz, CDCl3-
d) δ ppm 8.83 (d, J ) 6.63 Hz, 1 H), 8.44 (d, J ) 5.13 Hz, 1 H),
8.30 (d, J ) 8.43 Hz, 1 H), 8.23 (d, J ) 6.96 Hz, 1 H), 7.63–7.70
(m, 2H), 7.59 (s, 1H), 7.42 (s, 1H), 6.51 (d, J ) 5.15 Hz, 1 H),
3.95 (s, 6H). MS, m/z (C22H16FNO5): calcd, 393.1; found, 394.2
(MH).
3-(6,7-Dimethoxyquinolin-4-yloxy)isoquinoline-8-carboxylic
Acid (36b). A mixture of 4-fluoro-6,7-dimethoxyquinoline (27,
0.150 g, 0.724 mmol), methyl 3-hydroxyisoquinoline-8-carboxylate
(18, 0.294 g, 1.45 mmol), and cesium carbonate (0.590 g, 1.81
mmol) in DMF (3.0 mL) was combined in a sealable tube. The
mixture was exposed to microwave radiation at 120 °C for 3 h at
which point additional cesium carbonate (0.295 g, 0.90 mmol) was
added and the whole was exposed to microwave irradiation at 120
°C for an additional 4 h. The mixture was cooled to room
temperature, diluted with water (4 mL), and acidified to pH 3 with
1 N HCl. The resulting brown precipitate was filtered and washed
with water to give the title compound (0.172 g, 0.45 mmol, 63%
yield) as a brown solid. MS, m/z (C21H16N2O5): calcd, 376.1; found,
377.0 (MH).
7-(6,7-Dimethoxyquinolin-4-yloxy)quinoline-4-carboxylic Acid
(36c). The title compound was prepared from 7-hydroxyquinoline-
4-carboxylic acid (15) using a method analogous to the preparation
of compound 31c. Yield: 138 mg, 30%. 1H NMR (400 MHz,
DMSO-d6) δ ppm 8.86 (d, J ) 4.43 Hz, 1 H), 8.82 (d, J ) 9.23
Hz, 1 H), 8.48 (d, J ) 4.83 Hz, 1 H), 7.70 (s, 1 H), 7.61 (d, J )
4.00 Hz, 1 H), 7.51–7.54 (m, 2H), 7.41 (s, 1H), 6.63 (d, J ) 4.85
Hz, 1 H), 3.94 (s, 3H), 3.90 (s, 3H). MS, m/z (C22H16FNO5): calcd,
393.1; found, 394.2 (MH). MS, m/z (C21H16N2O5): calcd, 376.1;
found, 377.3 (MH).
6-(6,7-Dimethoxyquinolin-4-ylamino)-1-naphthoic Acid (37a).
A solution of methyl 6-amino-1-naphthoate (21, 300 mg, 1.50
mmol) and 4-chloro-6,7-dimethoxyquinoline (35, 416 mg, 1.80
mmol) in 6 mL of isopropyl alcohol was treated with trifluoroacetic
acid (287 µL, 3.70 mmol). After the mixture was heated at 90 °C
for 15 min, another 6 mL of isopropyl alcohol was added and the
mixture was heated at 90 °C for 8 h. The mixture was allowed to
cool to room temperature and placed in the refrigerator overnight.
The resulting precipitate was filtered and washed with methanol to
provide methyl 6-(6,7-dimethoxyquinolin-4-ylamino)-1-naphthoate
(550 mg, 95%) as a yellow solid. 1H NMR (400 MHz, DMSO-d6)
δ ppm 8.91 (d, J ) 9.22 Hz, 1 H), 8.38 (d, J ) 6.95 Hz, 1 H), 8.26
(d, J ) 8.21 Hz, 1 H), 8.23 (s, 1 H), 8.19 (d, J ) 7.20 Hz, 1 H),
8.16 (d, J ) 2.02 Hz, 1 H), 7.80 (dd, J ) 9.16, 2.21 Hz, 1 H),
7.65–7.73 (m, 1 H), 7.49 (s, 1 H), 6.92 (d, J ) 6.95 Hz, 1 H), 4.04
(s, 3 H), 4.00 (s, 3 H), 3.98 (s, 3 H). MS, m/z (C23H20N2O4): calcd,
388.1; found, 389.1 (MH). A solution of the derived ester (275
mg, 0.71 mmol) in 5 mL of methanol was treated with 1.5 mL of
6 N NaOH. After the mixture was stirred for 8 h, the organics were
removed in vacuo, the white mixture was diluted with 5 mL of
water, and the pH was adjusted to 3–4 with 1 N HCl. The resulting
solid was filtered and washed with ether to provide the title
compound (256 mg, 94%) as a slightly green solid that was used
immediately in the next step. MS, m/z (C22H18N2O4): calcd, 374.1;
found, 375.1 (MH).
6-(Pyridin-4-yloxy)-1-naphthoic Acid (31a). The title com-
pound was prepared from 6-hydroxy-1-naphthoic acid (10) using
a method analogous to the preparation of compound 31c. Yield:
1
1.09 g, 32%. H NMR (400 MHz, DMSO-d6) δ ppm 13.26 (s, 1
H), 9.00 (d, J ) 9.35 Hz, 1 H), 8.48–8.53 (m, 2 H), 8.14–8.20 (m,
2 H), 7.83 (d, J ) 2.53 Hz, 1 H), 7.61–7.68 (m, 1 H), 7.52 (dd, J
) 9.41, 2.59 Hz, 1 H), 7.04 (dd, J ) 4.80, 1.52 Hz, 2 H). MS, m/z
(C16H11NO3): calcd, 265.1; found, 266.1 (MH).
6-(7H-Pyrrolo[2,3-d]pyrimidin-4-yloxy)-1-naphthoic Acid (31b).
The title compound was prepared from 6-hydroxy-1-naphthoic acid
(10) using a method analogous to the preparation of compound
31c. Yield: 3.32 g, 38%. MS, m/z (C17H11N3O3): calcd, 305.1; found,
306.1 (MH).
6-(Pyrimidin-4-yloxy)-1-naphthoic Acid (31d). The title com-
pound was prepared from 6-hydroxy-1-naphthoic acid (10) using
a method analogous to the preparation of compound 31c. Yield:
5.92 g, 87%. MS, m/z (C15H10N2O3): calcd, 266.1; found, 267.1
(MH).
6-(2-(Methylamino)pyridin-4-yloxy)-1-naphthoic Acid (34a).
Carboxylic acid 33a was prepared from 6-hydroxy-1-naphthoic acid
(10) using a method analogous to the preparation of compound
31c. This procedure furnished 6-(pyridin-4-yloxy)-1-naphthoic acid
(33a, 2.55 g, 68%) as an off-white solid. Acid 33a (6.60 g, 22.0
mmol) was added to a melt of N-methylamine hydrochloride (73.6
g, 109 mmol) at 235 °C in one portion. The mixture was maintained
at this temperature for 3 min at which point it was removed from
the oil bath and allowed to cool to room temperature. To the
resulting brown oil were added water (100 mL) and ethyl acetate
(100 mL). After the mixture was stirred for 30 min, the resulting
white precipitate was filtered and washed with ethyl acetate.
Purification of this residue by silica gel chromatography (5%
CH3OH in CH2Cl2) provided the title compound (4.90 g, 76%) as
a white solid. MS, m/z (C17H14N2O3): calcd, 294.1; found, 295.3
(MH).
6-(6-(Methylamino)pyrimidin-4-yloxy)-1-naphthoic Acid (34b).
Carboxylic acid 33b was prepared from 6-hydroxy-1-naphthoic acid
(10) using a method analogous to the preparation of compound
31c. This procedure furnished 6-(6-chloropyrimidin-4-yloxy)-1-
naphthoic acid (33b, 1.55 g, 38%) as an off-white solid. The title
compound was prepared from 33b using a method analogous to
1
the preparation of 33a. Yield: 1.50 g, 98%. H NMR (400 MHz,
DMSO-d6) δ ppm 8.90 (d, J ) 9.17 Hz, 1 H), 8.11–8.12 (m, 3 H),
7.76 (s, 1 H), 7.59 (t, J ) 7.33 Hz, 1 H), 7.43 (d, J ) 9.16 Hz, 1
H), 7.34 (s, 1 H), 5.84 (s, 1 H), 2.76 (s, 3 H). MS, m/z (C16H13N3O3):
calcd, 295.1; found, 296.1 (MH).
6-(2-(Methylamino)pyrimidin-4-yloxy)-1-naphthoic Acid (34c).
The title compound was prepared from 6-hydroxy-1-naphthoic acid
(10) using a method analogous to the preparation of compound
31c. This procedure furnished 6-(2-chloropyrimidin-4-yloxy)-1-
naphthoic acid (33c, 6.00 g, 88%) as a white solid. The derived
acid 33c (1.00 g, 3.33 mmol) was taken up in 20 mL of THF and
cooled to 0 °C at which point N-methylamine (16.6 mL, 2 M in
THF) was added. The reaction vessel was sealed, and the solution
was allowed to warm to room temperature where it was maintained
6-((6,7-Dimethoxyquinolin-4-yl)(methyl)amino)-1-naphtho-
ic Acid (37b). To a suspension of methyl 6-(6,7-dimethoxyquinolin-
4-ylamino)-1-naphthoate (125 mg, 0.32 mmol) in 3 mL of DMF at
0 °C was added sodium hydride (20 mg, 0.48 mmol). The resulting
mixture was allowed to warm to room temperature for 30 min
before being cooled to 0 °C at which point methyl iodide (30 µL,
0.48 mmol) was introduced. After warming to room temperature

Naphthamides as Inhibitors
Journal of Medicinal Chemistry, 2008, Vol. 51, No. 6 1661
and being stirred for 30 min, the orange mixture was recooled to
0 °C and additional sodium hydride (20 mg, 0.48 mmol) was added.
After the mixture was stirred at 0 °C for 10 min, additional methyl
iodide (30 µL, 0.48 mmol) was added to the reaction mixture. The
mixture was allowed to warm to room temperature and was stirred
for 1 h before being quenched with 10 mL of saturated NH4Cl.
Ethyl acetate (10 mL) was added, and the layers were separated.
The aqueous layer was extracted with ethyl acetate (2 × 10 mL),
and the combined organics were washed sequentially with water
and brine before being dried over sodium sulfate. The mixture was
filtered and concentrated to provide an orange residue. Purification
by silica gel chromatography (0–10% CH3OH in CH2Cl2) provided
methyl 6-((6,7-dimethoxyquinolin-4-yl)(methyl)amino)-1-naph-
thoate (40 mg, 31%, two steps) as a yellow solid that was used
immediately in the next step. MS, m/z (C24H22N2O4): calcd, 402.2;
found, 403.3 (MH).
N-(4-Chlorophenyl)-6-(pyrimidin-4-yloxy)-1-naphtha-
mide (42). To a solution of 6-(pyrimidin-4-yloxy)-1-naphthoic acid
(31d, 100 mg, 0.37 mmol), diisopropylethylamine (102 µL, 0.75
mmol), 1-hydroxy-7-azabenztriazole (HOAt) (51 mg, 0.37 mmol),
and N-ethyl-N′-(3-dimethylaminopropyl)carbodiimide hydrochloride
(EDCI) (108 mg, 0.56 mmol) in 0.5 mL of CH2Cl2 and 100 mL of
DMF was added 4-chloroaniline. After being stirred for 4 h, the
mixture was concentrated and purified by HPLC to provide the
title compound (41 mg, 29%) as a white solid. HPLC purity: 99%
1
(system A). H NMR (400 MHz, DMSO-d6) δ ppm 10.76 (s, 1
H), 8.78 (s, 1 H), 8.74 (d, J ) 5.81 Hz, 1 H), 8.27 (d, J ) 9.09 Hz,
1 H), 8.10 (d, J ) 7.83 Hz, 1 H), 7.91 (d, J ) 2.15 Hz, 1 H), 7.87
(s, 1 H), 7.85 (s, 1 H), 7.80 (d, J ) 6.95 Hz, 1 H), 7.67 (t, J ) 7.71
Hz, 1 H), 7.43–7.53 (m, 3 H), 7.26 (d, J ) 5.81 Hz, 1 H). HRMS
(C21H15ClN3O2)+: calcd, 376.084 73; found, 376.085 13. Anal.
(C21H14ClN3O2) C, H, N.
N-(4-Chlorophenyl)-6-(2-(methylamino)pyrimidin-4-yloxy)-1-
naphthamide (43). The title compound was prepared from 6-(2-
(methylamino)pyrimidin-4-yloxy)-1-naphthoic acid (34c) using a
method analogous to the preparation of compound 6. Yield: 30 mg,
4-(5-((4-Chlorophenyl)carbamoyl)naphthalen-2-yloxy)-N-me-
thylpicolinamide (6). To a suspension of 6-(2-(methylcarbam-
oyl)pyridin-4-yloxy)-1-naphthoic acid 31c (50 mg, 0.15 mmol) in
2 mL of CH2Cl2 was added oxalyl chloride (28 µL, 0.31 mmol)
followed by 1 µL of DMF. After being stirred for 45 min, the
resulting suspension was concentrated to provide the corresponding
acid chloride as a yellow solid. The derived solid was taken up in
2 mL of CH2Cl2 at which point triethylamine (108 mL, 0.77 mmol)
and 4-chloroaniline (20 mg, 0.15 mmol) were added. After being
stirred for 1 h, the mixture was concentrated and purified by silica
gel chromatography (50% acetone in hexanes) to provide 4-(5-((4-
chlorophenyl)carbamoyl)naphthalen-2-yloxy)-N-methylpicolina-
mide (6) (42 mg, 63%) as an off-white solid. HPLC purity: 99%
1
22%. HPLC purity: 96% (system A); 97% (system B). H NMR
(400 MHz, DMSO-d6) δ ppm 10.74 (s, 1 H), 8.24 (s, 1 H), 8.22 (s,
1 H), 8.09 (d, J ) 8.21 Hz, 1 H), 7.83–7.89 (m, 4 H), 7.77 (d, J )
6.82 Hz, 1 H), 7.61–7.68 (m, 1 H), 7.42–7.48 (m, 4 H), 3.33 (s, 3
H). HRMS (C22H18ClN4O2)+: calcd, 405.111 28; found, 405.112
05.
N-(4-Chlorophenyl)-6-(6-(methylamino)pyrimidin-4-yloxy)-1-
naphthamide (44). The title compound was prepared from 6-(6-
(methylamino)pyrimidin-4-yloxy)-1-naphthoic acid (34b) using a
method analogous to the preparation of compound 42. Yield: 53
1
1
(system A); 96% (system C). H NMR (400 MHz, DMSO-d6) δ
mg, 68%. HPLC purity: 99% (system A); 100% (system B). H
ppm 10.78 (s, 1 H), 8.81 (d, J ) 4.93 Hz, 1 H), 8.57 (d, J ) 5.56
Hz, 1 H), 8.32 (d, J ) 9.22 Hz, 1 H), 8.12 (d, J ) 8.46 Hz, 1 H),
7.91 (d, J ) 2.53 Hz, 1 H), 7.83–7.88 (m, 2 H), 7.81 (d, J ) 6.57
Hz, 1 H), 7.65–7.72 (m, 1 H), 7.51 (dd, J ) 9.22, 2.53 Hz, 1 H),
7.43–7.48 (m, 3 H), 7.28 (dd, J ) 5.62, 2.59 Hz, 1 H), 2.79 (d, J
) 4.93 Hz, 3 H). HRMS (C24H19ClN3O3)+: calcd, 432.110 95;
found, 432.111 05.
NMR (400 MHz, DMSO-d6) δ ppm 10.75 (s, 1 H), 8.23 (d, J )
9.22 Hz, 1 H), 8.10–8.19 (m, 1 H), 8.08 (d, J ) 8.21 Hz, 1 H),
7.87 (s, 1 H), 7.85 (s, 1 H), 7.79 (d, J ) 2.40 Hz, 1 H), 7.76 (d, J
) 6.82 Hz, 1 H), 7.61–7.67 (m, 1 H), 7.39–7.48 (m, 3 H), 7.31–7.39
(m, 1 H), 5.89 (s, 1 H), 2.79 (s, 3H). HRMS (C22H18ClN4O2)+:
calcd, 405.111 28; found, 405.111 78.
6-(7H-Pyrrolo[2,3-d]pyrimidin-4-yloxy)-N-(4-chlorophenyl)-
1-naphthamide (45). The title compound was prepared from (31b)
using a method analogous to the preparation of compound 6. Yield:
N-(4-Chlorophenyl)-6-(pyridin-4-yloxy)-1-naphthamide (40).
The title compound was prepared from 6-(pyridin-4-yloxy)-1-
naphthoic acid (31a) using a method analogous to the preparation
of compound 6. Yield: 55 mg, 56%. HPLC purity: 99% (system
A). 1H NMR (400 MHz, DMSO-d6) δ ppm 10.75 (s, 1 H), 8.51 (d,
J ) 6.19 Hz, 2 H), 8.31 (d, J ) 9.22 Hz, 1 H), 8.10 (d, J ) 8.34
Hz, 1 H), 7.81–7.89 (m, 3 H), 7.79 (d, J ) 6.82 Hz, 1 H), 7.63–7.70
(m, 1 H), 7.41–7.51 (m, 3 H), 7.03 (dd, J ) 4.80, 1.52 Hz, 2 H).
HRMS (C22H16ClN2O2)+: calcd, 375.089 48; found, 375.089 33.
Anal. (C22H15ClN2O2) C, H, N.
1
53 mg, 48%. HPLC purity: 99% (system A); 99% (system B). H
NMR (400 MHz, DMSO-d6) δ ppm 12.28 (s, 1 H), 10.79 (s, 1 H),
8.31 (s, 1 H), 8.26 (d, J ) 9.29 Hz, 1 H), 8.10 (d, J ) 8.02 Hz, 1
H), 7.94 (d, J ) 2.45 Hz, 1 H), 7.87 (d, J ) 8.80 Hz, 2 H), 7.79
(d, J ) 6.16 Hz, 1 H), 7.63–7.69 (m, 1 H), 7.55 (dd, J ) 9.24,
2.49 Hz, 1 H), 7.52 (d, J ) 3.52 Hz, 1 H), 7.42–7.48 (m, 2 H),
6.56 (d, J ) 3.42 Hz, 1 H). HRMS (C23H16ClN4O2)+: calcd,
415.095 63; found, 415 095 93.
N-(4-Chlorophenyl)-6-(quinolin-4-yloxy)-1-naphthamide (46).
The title compound was prepared from 6-(quinolin-4-yloxy)-1-
naphthoic acid (29b) using a method analogous to the preparation
of compound 6. Yield: 160 mg, 62%. HPLC purity: 99% (system
A); 99% (system B). 1H NMR (400 MHz, DMSO-d6) δ ppm 10.78
(s, 1 H), 8.74 (d, J ) 5.05 Hz, 1 H), 8.34–8.39 (m, 2 H), 8.12 (d,
J ) 8.21 Hz, 1 H), 8.08 (d, J ) 8.46 Hz, 1 H), 7.95 (d, J ) 2.53
Hz, 1 H), 7.79-7.90 (m, 4 H), 7.66–7.73 (m, 2 H), 7.60 (dd, J )
9.09, 2.53 Hz, 1 H), 7.46 (d, J ) 8.84 Hz, 2 H), 6.75 (d, J ) 5.05
Hz, 1 H). HRMS (C26H18ClN2O2)+: calcd, 425.105 13; found,
425.106 01. Anal. Calcd (C26H17ClN2O3) C, 73.50; H, 4.03; N, 6.59.
Found: C, 70.91; H, 4.34; N, 6.21.
N-(4-Chlorophenyl)-6-(7-methoxyquinolin-4-yloxy)-1-naph-
thamide (47). The title compound was prepared from 6-(7-
methoxyquinolin-4-yloxy)-1-naphthoic acid (29c) using a method
analogous to the preparation of compound 6 modified such that
NaHCO3 (5 equiv) was employed as the base. Yield: 69 mg, 55%.
HPLC purity: 99% (system A). 1H NMR (400 MHz, DMSO-d6) δ
ppm 10.77 (s, 1 H), 8.66 (d, J ) 5.18 Hz, 1 H), 8.34 (d, J ) 9.22
Hz, 1 H), 8.25 (d, J ) 9.09 Hz, 1 H), 8.11 (d, J ) 8.34 Hz, 1 H),
7.92 (d, J ) 2.40 Hz, 1 H), 7.87 (d, J ) 8.84 Hz, 2 H), 7.81 (d, J
) 6.44 Hz, 1 H), 7.64–7.71 (m, 1 H), 7.58 (dd, J ) 9.16, 2.46 Hz,
1 H), 7.42–7.48 (m, 3 H), 7.32 (dd, J ) 9.16, 2.46 Hz, 1 H), 6.61
N-(4-Chlorophenyl)-6-(2-(methylamino)pyridin-4-yloxy)-1-
naphthamide (41). To a solution of 6-(2-(methylamino)pyridin-
4-yloxy)-1-naphthoic acid (34a, 170 mg, 0.58 mmol) and DIPEA
(201 µL, 1.5 mmol) in 3 mL of DMF were added 2-(1H-
benzotriazole-1-yl)-1,1,3,3-tetramethyluronium tetrafluoroborate
(TBTU) (223 mg, 0.69 mmol) and 4-chloroaniline (110 mg, 0.86).
After the mixture was stirred for 5 h, the reaction was quenched
with 1 mL of 1 N HCl. The pH was adjusted to 7 with 1 N NaOH,
and the aqueous layer was extracted with ethyl acetate (3 × 15
mL). The combined organic layers were washed sequentially with
water and brine before being dried over sodium sulfate and filtered.
Concentration provided a residue that was purified by silica gel
chromatography (0–10% CH3OH in CH2Cl2) to provide the title
compound (125 mg, 54%) as a white solid. HPLC purity: 91%
1
(system A); 94% (system B). H NMR (400 MHz, DMSO-d6) δ
ppm 10.76 (s, 1 H), 8.53 (s, 1 H), 8.22–8.29 (m, 1 H), 8.07 (d, J
) 8.08 Hz, 1 H), 7.92 (d, J ) 6.69 Hz, 1 H), 7.85 (d, J ) 8.21 Hz,
2 H), 7.75 (s, 2 H), 7.60–7.67 (m, 1 H), 7.37–7.48 (m, 2 H),
6.44–6.54 (m, 1 H), 6.21 (d, J ) 3.66 Hz, 1 H), 5.91 (s, 1 H), 2.71
(s, 3 H). HRMS (C23H19ClN3O2)+: calcd, 404.116 03; found,
404.11796. Anal. Calcd for C23H18ClN3O2: C, 68.40; H, 4.49; N,
10.40. Found: C, 69.10; H, 4.51; N, 10.20.

1662 Journal of Medicinal Chemistry, 2008, Vol. 51, No. 6
Harmange et al.
(d, J ) 5.18 Hz, 1 H), 3.96 (s, 3 H). HRMS (C27H20ClN2O3)+:
calcd, 455.115 70; found, 455.118 57. Anal. (C27H19ClN2O3) C,
H, N.
6-(6,7-Dimethoxyquinolin-4-yloxy)-N-phenyl-1-naphtha-
mide (52). The title compound was prepared from 6-(6,7-dimethoxy-
quinolin-4-yloxy)-1-naphthoic acid (29a) using a method analogous
to the preparation of compound 48. Yield: 326 mg, 34%. HPLC
N-(4-Chlorophenyl)-6-(6,7-dimethoxyquinolin-4-yloxy)-1-naph-
thamide (48). To a solution of 6-(6,7-dimethoxyquinolin-4-yloxy)-
1-naphthoic acid (29a, 19.0 g, 50.6 mmol) in 127 mL of DMF
were sequentially added triethylamine (35.3 mL, 253 mmol) and
O-(7-azabenzotriazol-1-yl)-N,N,N′,N′-tetramethyluronium hexafluo-
rophosphate (HATU) (25.0 g, 65.8 mmol). After the mixture was
stirred for 2 h, 4-chloroaniline (12.9 g, 101 mmol) was added and
stirring was continued for 8 h. The mixture was diluted with 500
mL of ethyl acetate and washed sequentially with saturated
NaHCO3, water and brine before being dried over sodium sulfate.
Filtration and concentration provided a solid that was passed through
silica gel (10% CH3OH in CH2Cl2) to provide a solid that was then
recrystallized to provide the title compound (12.5 g, 51%) as a light-
yellow solid. Yield: 12.5 g, 51%. HPLC purity: 99% (system A).
1H NMR (400 MHz, DMSO-d6) δ ppm 10.77 (s, 1 H), 8.50 (d, J
) 5.18 Hz, 1 H), 8.33 (d, J ) 9.35 Hz, 1 H), 8.10 (d, J ) 7.96 Hz,
1 H), 7.92 (s, 1 H), 7.83–7.90 (m, 2 H), 7.79 (d, J ) 6.06 Hz, 1
H), 7.63–7.71 (m, 1 H), 7.53–7.60 (m, 2 H), 7.40–7.50 (m, 3 H),
6.58 (d, J ) 5.18 Hz, 1 H), 3.96 (s, 3 H), 3.93 (s, 3 H). HRMS
(C28H22ClN2O4)+: calcd, 485.126 26; found, 485.127 69. Anal.
(C28H21ClN2O4 ·CH3OH) C, H, N.
N-(4-Chlorophenyl)-6-(3-fluoro-6,7-dimethoxyquinolin-4-yloxy)-
1-naphthamide (49). The title compound was prepared from 6-(3-
fluoro-6,7-dimethoxyquinolin-4-yloxy)-1-naphthoic acid (29f) using
a method analogous to the preparation of compound 42. Yield: 16
mg, 26%. HPLC purity: 90% (system A); 93% (system B). 1H NMR
(400 MHz, DMSO-d6) δ ppm 10.74 (s, 1 H), 8.86 (d, J ) 2.2 Hz,
1 H), 8.25 (d, J ) 9.5 Hz, 1 H), 7.97 (d, J ) 8.1 Hz, 1 H), 7.84 (d,
J ) 8.8 Hz, 2 H), 7.70 (d, J ) 6.2 Hz, 1 H), 7.55–7.61 (m, 2 H),
7.51 (s, 1 H), 7.44–7.47 (m, 1 H), 7.44 (d, J ) 8.8 Hz, 2 H), 7.26
(s, 1 H), 3.96 (s, 3 H), 3.82 (s, 3 H). MS (ESI, positive ion) m/z:
503.0 (M + H). Mass calcd for C28H20ClFN2O4: 502.1. HRMS
(C28H21ClFN2O4)+: calcd, 503.116 84; found, 503.117 23.
1
purity: 95% (system A). H NMR (400 MHz, DMSO-d6) δ ppm
10.65 (s, 1 H), 8.51 (s, 1 H), 8.36 (d, J ) 8.46 Hz, 1 H), 8.11 (d,
J ) 7.45 Hz, 1 H), 7.92 (s, 1 H), 7.74–7.86 (m, 3 H), 7.68 (t, J )
6.06 Hz, 1 H), 7.52–7.60 (m, 2 H), 7.44 (s, 1 H), 7.39 (t, J ) 6.82
Hz, 2 H), 7.14 (t, J ) 6.88 Hz, 1 H), 6.58 (s, 1 H), 3.97 (s, 3 H),
3.95 (s, 3 H). HRMS (C28H23N2O4)+: calcd, 451.165 23; found,
451.166 44. Anal. (C28H22N2O4 ·CH3OH) C, H, N.
6-(6,7-Dimethoxyquinolin-4-yloxy)-N-(2-fluorophenyl)-1-naph-
thamide (53). The title compound was prepared from 6-(6,7-
dimethoxyquinolin-4-yloxy)-1-naphthoic acid (29a) using a method
analogous to the preparation of compound 6. Yield: 147 mg, 34%.
HPLC purity: 95% (system A). 1H NMR (400 MHz, DMSO-d6) δ
ppm 10.42 (s, 1 H), 8.51 (d, J ) 5.18 Hz, 1 H), 8.42 (d, J ) 9.22
Hz, 1 H), 8.11 (d, J ) 8.08 Hz, 1 H), 7.92 (d, J ) 2.40 Hz, 1 H),
7.74–7.86 (m, 2 H), 7.67 (t, J ) 7.71 Hz, 1 H), 7.54-7.63 (m, 2
H), 7.44 (s, 1 H), 7.20–7.38 (m, 3 H), 6.59 (d, J ) 5.18 Hz, 1 H),
3.97 (s, 3 H), 3.95 (s, 3 H). HRMS (C28H22FN2O4)+: calcd,
469.155 81; found, 469.156 19. Anal. (C28H21FN2O4) C, H, N.
6-(6,7-Dimethoxyquinolin-4-yloxy)-N-(3-fluorophenyl)-1-naph-
thamide (54). The title compound was prepared from 6-(6,7-
dimethoxyquinolin-4-yloxy)-1-naphthoic acid (29a) using a method
analogous to the preparation of compound 6. Yield: 236 mg, 56%.
1
HPLC purity: 99% (system A); 99% (system B). H NMR (400
MHz, DMSO-d6) δ ppm 10.87 (s, 1 H), 8.52 (d, J ) 5.18 Hz, 1
H), 8.35 (d, J ) 9.22 Hz, 1 H), 8.12 (d, J ) 8.21 Hz, 1 H), 7.93
(d, J ) 2.53 Hz, 1 H), 7.84 (s, 1 H), 7.81 (d, J ) 6.19 Hz, 1 H),
7.68 (t, J ) 7.64 Hz, 1 H), 7.54–7.61 (m, 3 H), 7.37–7.47 (m, 2
H), 6.93–7.02 (m, 1 H), 6.59 (d, J ) 5.18 Hz, 1 H), 3.97 (s, 3 H),
3.95 (s, 3 H). HRMS (C28H22FN2O4)+: calcd, 469.155 81; found,
469.156 91.
6-(6,7-Dimethoxyquinolin-4-yloxy)-N-(4-fluorophenyl)-1-naph-
thamide (55). The title compound was prepared from 6-(6,7-
dimethoxyquinolin-4-yloxy)-1-naphthoic acid (29a) using a method
analogous to the preparation of compound 6. Yield: 237 mg, 55%.
HPLC purity: 95% (system A). 1H NMR (400 MHz, DMSO-d6) δ
ppm 10.68 (s, 1 H), 8.51 (d, J ) 5.18 Hz, 1 H), 8.35 (d, J ) 9.22
Hz, 1 H), 8.10 (d, J ) 8.08 Hz, 1 H), 7.91 (s, 1 H), 7.81–7.88 (m,
2 H), 7.79 (d, J ) 7.20 Hz, 1 H), 7.67 (t, J ) 7.58 Hz, 1 H),
7.53-7.60 (m, 2 H), 7.44 (s, 1 H), 7.26–7.22 (m, 2 H), 6.58 (d, J
) 5.18 Hz, 1 H), 3.98 (s, 3 H), 3.94 (s, 3 H). HRMS
(C28H22FN2O4)+: calcd, 469.155 81; found, 469.155 30. Anal.
(C28H21FN2O4 ·CH3OH) C, H, N.
N-(3-Chlorophenyl)-6-(6,7-dimethoxyquinolin-4-yloxy)-1-naph-
thamide (56). The title compound was prepared from 6-(6,7-
dimethoxyquinolin-4-yloxy)-1-naphthoic acid (29a) using a method
analogous to the preparation of compound 48. Yield: 260 mg, 39%.
HPLC purity: 95% (system A). 1H NMR (400 MHz, DMSO-d6) δ
ppm 10.82 (s, 1 H), 8.52 (d, J ) 5.18 Hz, 1 H), 8.36 (d, J ) 9.22
Hz, 1 H), 8.12 (d, J ) 8.08 Hz, 1 H), 8.05 (s, 1 H), 7.92 (d, J )
2.53 Hz, 1 H), 7.79–7.84 (m, 1 H), 7.65–7.73 (m, 2 H), 7.55–7.60
(m, 2 H), 7.39–7.46 (m, 2 H), 7.18–7.24 (m, 1 H), 6.60 (d, J )
5.18 Hz, 1 H), 3.97 (s, 3 H), 3.95 (s, 3 H). HRMS (C28H22ClN2O4)+:
calcd, 485.126 26; found, 485.126 99. Anal. (C28H22ClN2O4 ·
1.6H2O) C, H, N.
4-(5-((4-Chlorophenyl)carbamoyl)naphthalen-2-yloxy)-7-meth-
oxyquinoline-6-carboxamide (50). A 10 mL flask was charged
with 6-(6-carbamoyl-7-methoxyquinolin-4-yloxy)-1-naphthoic acid
(29e, 1.00 g, 2.58 mmol). Thionyl chloride (10 mL) was added,
and the mixture was heated at 60 °C for 1 h before being cooled to
room temperature. Concentration under reduced pressure provided
the acid chloride as a brown solid that was used immediately in
the next step. A solution of the derived acid chloride (200 mg,
0.49 mmol) was taken up in 3 mL of pyridine and treated with
4-chloroaniline (55 mg, 0.59 mmol). After being stirred for 8 h,
the mixture was concentrated and purified by silica gel chroma-
tography (10% CH3OH in CH2Cl2) to provide the title compound
(189 mg, 80%) as a white solid. HPLC purity: 100% (system A).
1H NMR (400 MHz, DMSO-d6) δ ppm 10.78 (s, 1 H), 8.73 (s, 1
H), 8.71 (d, J ) 5.18 Hz, 1 H), 8.35 (d, J ) 9.09 Hz, 1 H),
8.10–8.15 (m, 1 H), 7.96 (d, J ) 2.65 Hz, 1 H), 7.84–7.89 (m, 3
H), 7.82 (d, J ) 5.94 Hz, 1 H), 7.76 (s, 1 H), 7.66–7.72 (m, 1 H),
7.60 (dd, J ) 9.16, 2.59 Hz, 1 H), 7.57 (s, 1 H), 7.47 (s, 1 H), 7.45
(s, 1 H), 6.63 (d, J ) 5.31 Hz, 1 H), 4.06 (s, 3 H). HRMS
(C28H21ClN3O4)+: calcd, 498.121 51; found, 498.123 35. Anal.
(C28H20ClN3O4 ·CH3OH) C, H, N.
N-(4-Chlorophenyl)-6-(6,7-dimethoxyquinazolin-4-yloxy)-1-
naphthamide (51). The title compound was prepared from 6-(6,7-
dimethoxyquinazolin-4-yloxy)-1-naphthoic acid (29d) using a
method analogous to the preparation of compound 42. Yield: 38
mg, 49%. HPLC purity: 99% (system A). 1H NMR (400 MHz,
DMSO-d6) δ ppm 10.78 (s, 1 H), 8.55 (s, 1 H), 8.29 (d, J ) 9.35
Hz, 1 H), 8.12 (d, J ) 8.21 Hz, 1 H), 8.00 (d, J ) 2.27 Hz, 1 H),
7.87 (d, J ) 8.97 Hz, 2 H), 7.81 (d, J ) 6.82 Hz, 1 H), 7.63–7.71
(m, 2 H), 7.61 (dd, J ) 9.16, 2.34 Hz, 1 H), 7.47 (s, 1 H), 7.45 (s,
1 H), 7.43 (s, 1 H), 4.01 (s, 6 H). HRMS (C27H21ClN3O4)+: calcd,
486.121 51; found, 486.122 95. Anal. Calcd for (C27H20ClN3O4):
C, 66.74; H, 4.15; N, 8.65. Found: C, 66.11; H, 4.28; N, 8.66.
6-(6,7-Dimethoxyquinolin-4-yloxy)-N-p-tolyl-1-naphtha-
mide (57). The title compound was prepared from 6-(6,7-dimethox-
yquinolin-4-yloxy)-1-naphthoic acid (29a) using a method analo-
gous to the preparation of compound 48. Yield: 325 mg, 86%.
HPLC purity: 95% (system A). 1H NMR (400 MHz, DMSO-d6) δ
ppm 10.84 (s, 1 H), 8.53 (d, J ) 5.16 Hz, 1 H), 8.32 (d, J ) 9.22
Hz, 1 H), 8.09 (d, J ) 8.30 Hz, 1 H), 7.90 (d, J ) 2.62 Hz, 1 H),
7.74–7.89 (m, 2 H), 7.65 (t, J ) 7.70 Hz, 1 H), 7.51–7.61 (m, 3
H), 7.31–7.44 (m, 2 H), 6.91–7.00 (m, 1 H), 6.63 (d, J ) 5.21 Hz,
1 H), 3.98 (s, 3 H), 3.93 (s, 3 H), 2.40 (s, 3 H). HRMS
(C29H25N2O4)+: calcd, 465.180 88; found, 465.181 10. Anal.
(C29H24N2O4) C, H, N.

Naphthamides as Inhibitors
Journal of Medicinal Chemistry, 2008, Vol. 51, No. 6 1663
6-(6,7-Dimethoxyquinolin-4-yloxy)-N-(3-(trifluoromethyl)phe-
nyl)-1-naphthamide (58). The title compound was prepared from
6-(6,7-dimethoxyquinolin-4-yloxy)-1-naphthoic acid (29a) using a
method analogous to the preparation of compound 6. Yield: 36 mg,
60%. HPLC purity: 100% (system A); 100% (system B). 1H NMR
(400 MHz, DMSO-d6) δ ppm 10.97 (s, 1 H), 8.0 (d, J ) 5.45 Hz,
1 H), 8.38 (d, J ) 9.37 Hz, 1 H), 8.10 (d, J ) 8.71 Hz, 1 H),
8.06–8.08 (m, 2 H), 7.97 (d, J ) 2.30 Hz, 1 H), 7.81 (d, J ) 6.30
Hz, 1 H), 7.78 (s, 1 H), 7.77 (s, 1 H), 7.66–7.69 (m, 1 H), 7.51–7.62
(m, 2 H), 7.44 (s, 1 H), 6.65 (d, J ) 5.34 Hz, 1 H) 3.96 (s, 3 H),
3.95 (s, 3 H). HRMS (C29H22F3N2O4)+: calcd, 519.152 62; found,
519.153 73.
553.113 65; found, 553.113 00. Anal. Calcd for C29H20ClF3N2O4:
C, 62.99; H, 3.65; N, 5.07. Found: C, 63.45; H, 3.75; N, 5.10.
6-(6,7-Dimethoxyquinolin-4-yloxy)-N-(pyridin-2-yl)-1-naph-
thamide (64). The title compound was prepared from 6-(6,7-
dimethoxyquinolin-4-yloxy)-1-naphthoic acid (29a) using a method
analogous to the preparation of compound 6. Yield: 113 mg, 31%.
HPLC purity: 99% (system A). 1H NMR (400 MHz, DMSO-d6) δ
ppm 11.10 (s, 1 H), 8.51 (d, J ) 5.18 Hz, 1 H), 8.40 (d, J ) 3.79
Hz, 1 H), 8.37 (d, J ) 9.47 Hz, 1 H), 8.32 (d, J ) 8.34 Hz, 1 H),
8.10 (d, J ) 8.21 Hz, 1 H), 7.87–7.93 (m, 3 H), 7.81 (d, J ) 6.69
Hz, 1 H), 7.62–7.68 (m, 1 H), 7.55–7.60 (m, 2 H), 7.44 (s, 1 H),
7.19–7.23 (m, 1 H), 3.97 (s, 3 H), 3.95 (s, 3 H). HRMS
(C27H22N3O4)+: calcd, 452.160 48; found, 452.160 62. Anal.
(C27H21N3O4 ·0.6H2O) C, H, N.
6-(6,7-Dimethoxyquinolin-4-yloxy)-N-(pyridin-3-yl)-1-naph-
thamide (65). The title compound was prepared from 6-(6,7-
dimethoxyquinolin-4-yloxy)-1-naphthoic acid (29a) using a method
analogous to the preparation of compound 6. Yield: 264 mg, 32%.
HPLC purity: 95% (system A). 1H NMR (400 MHz, DMSO-d6) δ
ppm 10.85 (s, 1 H), 8.97 (d, J ) 2.40 Hz, 1 H), 8.52 (d, J ) 5.18
Hz, 1 H), 8.39 (d, J ) 9.22 Hz, 1 H), 8.36 (dd, J ) 4.61, 1.20 Hz,
1 H), 8.28 (d, J ) 9.35 Hz, 1 H), 8.13 (d, J ) 8.34 Hz, 1 H), 7.93
(d, J ) 2.53 Hz, 1 H), 7.85 (d, J ) 6.95 Hz, 1 H), 7.65–7.73 (m,
1 H), 7.55–7.62 (m, 2 H), 7.40–7.48 (m, 2 H), 6.60 (d, J ) 5.18
Hz, 1 H), 3.97 (s, 3 H), 3.95 (s, 3 H). HRMS (C27H22N3O4)+: calcd,
452.160 48; found, 452.160 77. Anal. (C27H21N3O4) C, H, N.
6-(6,7-Dimethoxyquinolin-4-yloxy)-N-(pyridin-4-yl)-1-naph-
thamide (66). The title compound was prepared from 6-(6,7-
dimethoxyquinolin-4-yloxy)-1-naphthoic acid (29a) using a method
analogous to the preparation of compound 49. Yield: 225 mg, 53%.
HPLC purity: 97% (system A). 1H NMR (400 MHz, DMSO-d6) δ
ppm 11.19 (s, 1 H), 8.51–8.62 (m, 3 H), 8.37 (d, J ) 9.35 Hz, 1
H), 8.16 (d, J ) 8.08 Hz, 1 H), 7.96 (d, J ) 2.40 Hz, 1 H),
7.84–7.92 (m, 3 H), 7.71 (t, 1 H), 7.53–7.63 (m, 2 H), 7.46 (s, 1
H), 6.64 (d, J ) 5.30 Hz, 1 H), 3.98 (s, 3 H), 3.96 (s, 3 H). HRMS
(C27H22N3O4)+: calcd, 452.160 48; found, 455.160 52. Anal.
(C27H22N3O4 ·1.6H2O) C, H, N.
6-(6,7-Dimethoxyquinolin-4-yloxy)-N-(4-(trifluoromethyl)phe-
nyl)-1-naphthamide (59). The title compound was prepared from
6-(6,7-dimethoxyquinolin-4-yloxy)-1-naphthoic acid (29a) using a
method analogous to the preparation of compound 48. Yield: 39
mg, 66%. HPLC purity: 95% (system A). 1H NMR (400 MHz,
DMSO-d6) δ ppm 11.00 (s, 1 H), 8.52 (d, J ) 5.30 Hz, 1 H), 8.36
(d, J ) 9.47 Hz, 1 H), 8.13 (d, J ) 8.21 Hz, 1 H), 8.06 (s, 1 H)
8.04 (s, 1 H), 7.93 (d, J ) 2.40 Hz, 1 H), 7.84 (d, J ) 6.69 Hz, 1
H), 7.78 (s, 1 H), 7.76 (s, 1 H), 7.65–7.72 (m, 1 H), 7.53-7.62 (m,
2 H), 7.44 (s, 1 H), 6.60 (d, J ) 5.18 Hz, 1 H), 3.97 (s, 3 H), 3.95
(s, 3 H). HRMS (C29H22F3N2O4)+: calcd, 519.152 62; found,
519.152 02 Anal. (C29H21F3N2O4 ·0.5CH3OH) C, H, N.
N-(4-tert-Butylphenyl)-6-(6,7-dimethoxyquinolin-4-yloxy)-1-
naphthamide (60). The title compound was prepared from 6-(6,7-
dimethoxyquinolin-4-yloxy)-1-naphthoic acid (29a) using a method
analogous to the preparation of compound 6. Yield: 27 mg, 46%.
1
HPLC purity: 100% (system A); 99% (system B). H NMR (400
MHz, DMSO-d6) δ ppm 10.55 (s, 1 H), 8.52 (d, J ) 5.18 Hz, 1
H), 8.35 (d, J ) 9.47 Hz, 1 H), 8.10 (d, J ) 7.83 Hz, 1 H), 7.91
(d, J ) 2.40 Hz, 1 H), 7.72–7.79 (m, 3 H), 7.64–7.70 (m, 1 H),
7.54–7.59 (m, 2 H), 7.44 (s, 1 H), 7.41 (s, 1 H), 7.39 (s, 1 H), 6.59
(d, J ) 5.31 Hz, 1 H), 3.97 (s, 3 H), 3.95 (s, 3 H), 1.30 (s, 9 H).
HRMS (C32H31N2O4)+: calcd, 507.227 83; found, 507.226 91.
N-(2,4-Dichlorophenyl)-6-(6,7-dimethoxyquinolin-4-yloxy)-1-
naphthamide (61). The title compound was prepared from 6-(6,7-
dimethoxyquinolin-4-yloxy)-1-naphthoic acid (29a) using a method
analogous to the preparation of compound 48. Yield: 95 mg, 26%.
6-(6,7-Dimethoxyquinolin-4-yloxy)-N-(thiazol-2-yl)-1-naph-
thamide (67). The title compound was prepared from 6-(6,7-
dimethoxyquinolin-4-yloxy)-1-naphthoic acid (29a) using a method
analogous to the preparation of compound 6. Yield: 240 mg, 51%.
HPLC purity: 97% (system A). 1H NMR (400 MHz, DMSO-d6) δ
ppm 12.85 (s, 1 H), 8.51 (d, J ) 5.31 Hz, 1 H), 8.41 (d, J ) 9.47
Hz, 1 H), 8.15 (d, J ) 8.21 Hz, 1 H), 7.93 (d, J ) 2.53 Hz, 1 H),
7.90 (d, J ) 7.20 Hz, 1 H), 7.64–7.71 (m, 1 H), 7.58–7.63 (m, 2
H), 7.57 (s, 1 H), 7.44 (s, 1 H), 7.35 (d, J ) 3.54 Hz, 1 H), 6.61
(d, J ) 5.31 Hz, 1 H), 3.97 (s, 3 H), 3.95 (s, 3 H). HRMS
(C25H20N3O4S)+: calcd, 458.116 90; found, 458.119 48. Anal.
(C25H19N3O4S·0.6H2O) C, H, N.
1
HPLC purity: 100% (system A). H NMR (400 MHz, DMSO-d6)
δ ppm 10.42 (s, 1 H), 8.51 (d, J ) 5.18 Hz, 1 H), 8.49 (d, J )
9.22 Hz, 1 H), 8.12 (d, J ) 8.08 Hz, 1 H), 7.92 (d, J ) 2.40 Hz,
1 H), 7.88 (d, J ) 6.44 Hz, 1 H), 7.74–7.81 (m, 2 H), 7.69 (t, J )
7.58 Hz, 1 H), 7.60 (dd, J ) 9.22, 2.53 Hz, 1 H), 7.57 (s, 1 H),
7.54 (dd, J ) 8.59, 2.15 Hz, 1 H), 7.44 (s, 1 H), 6.60 (d, J ) 5.31
Hz, 1 H), 3.97 (s, 3 H), 3.95 (s, 3 H). HRMS (C28H21Cl2N2O4)+:
calcd, 519.087 29; found, 519.088 78. Anal. (C28H20Cl2N2O4 ·
1.5CH3OH) C, H, N.
N-(3,5-Dichlorophenyl)-6-(6,7-dimethoxyquinolin-4-yloxy)-1-
naphthamide (62). The title compound was prepared from 6-(6,7-
dimethoxyquinolin-4-yloxy)-1-naphthoic acid (29a) using a method
analogous to the preparation of compound 48. Yield: 160 mg, 39%.
HPLC purity: 99% (system A). 1H NMR (400 MHz, DMSO-d6) δ
ppm 10.96 (s, 1 H), 8.52 (d, J ) 5.18 Hz, 1 H), 8.36 (d, J ) 8.84
Hz, 1 H), 8.14 (d, J ) 9.09 Hz, 1 H), 7.93 (t, J ) 2.21 Hz, 3 H),
7.84 (d, J ) 6.82 Hz, 1 H), 7.66–7.73 (m, 1 H), 7.55–7.61 (m, 2
H), 7.44 (s, 1 H), 7.39 (t, J ) 1.89 Hz, 1 H), 6.60 (d, J ) 5.05 Hz,
1 H), 3.97 (s, 3 H), 3.95 (s, 3 H). HRMS (C28H21Cl2N2O4)+: calcd,
519.087 29; found, 519. 090 80. Anal. (C28H20Cl2N2O4) C, H, N.
6-(6,7-Dimethoxyquinolin-4-yloxy)-N-(isoxazol-3-yl)-1-naph-
thamide (68). The title compound was prepared from 6-(6,7-
dimethoxyquinolin-4-yloxy)-1-naphthoic acid (29a) using a method
analogous to the preparation of compound 6. Yield: 77 mg, 22%.
HPLC purity: 95% (system A). 1H NMR (400 MHz, DMSO-d6) δ
ppm 11.71 (s, 1 H), 8.87-8.94 (m, 1 H), 8.51 (d, J ) 5.18 Hz, 1
H), 8.38 (d, J ) 9.35 Hz, 1 H), 8.13 (d, J ) 8.34 Hz, 1 H), 7.92
(d, J ) 2.40 Hz, 1 H), 7.82–7.88 (m, 1 H), 7.63–7.70 (m, 1 H),
7.54–7.61 (m, 2 H), 7.44 (s, 1 H), 7.15 (s, 1 H), 6.60 (d, J ) 5.18
Hz, 1 H), 3.97 (s, 3 H), 3.95 (s, 3 H). HRMS (C25H20N3O5)+: calcd,
442.139 75; found, 442.139 81. Anal. (C25H19N3O5 ·0.6CH3OH) C,
H, N.
N-(4-Chloro-3-(trifluoromethyl)phenyl)-6-(6,7-dimethoxyquin-
olin-4-yloxy)-1-naphthamide (63). The title compound was pre-
pared from 6-(6,7-dimethoxyquinolin-4-yloxy)-1-naphthoic acid
(29a) using a method analogous to the preparation of compound
6-(6,7-Dimethoxyquinolin-4-yloxy)-N-(5-methylisoxazol-3-yl)-
1-naphthamide (69). The title compound was prepared from 6-(6,7-
dimethoxyquinolin-4-yloxy)-1-naphthoic acid (29a) using a method
analogous to the preparation of compound 6. Yield: 50 mg, 30%.
1
48. Yield: 39 mg, 61%. HPLC purity: 95% (system A). H NMR
1
(400 MHz, DMSO-d6) δ ppm 10.96 (s, 1 H), 8.52 (d, J ) 5.18 Hz,
1 H), 8.38 (d, J ) 9.22 Hz, 1 H), 8.35 (s, 1 H), 8.13 (d, J ) 8.21
Hz, 1 H), 8.04 (d, J ) 8.08 Hz, 1 H), 7.93 (d, J ) 2.53 Hz, 1 H),
7.85 (d, 1 H), 7.61–7.72 (m, 2 H), 7.55–7.60 (m, 2 H), 7.51 (d, J
) 8.08 Hz, 1 H), 7.44 (s, 1 H), 6.60 (d, J ) 5.18 Hz, 1 H), 3.97
(s, 3 H), 3.95 (s, 3 H). HRMS (C29H21ClF3N2O4)+: calcd,
HPLC purity: 100% (system A). H NMR (400 MHz, DMSO-d6)
δ ppm 11.51 (s, 1 H), 8.46 (d, J ) 5.18 Hz, 1 H), 8.31 (d, J )
9.22 Hz, 1 H), 8.07 (d, J ) 8.46 Hz, 1 H), 7.86 (d, J ) 2.40 Hz,
1 H), 7.77 (d, J ) 6.82 Hz, 1 H), 7.60 (d, J ) 15.41 Hz, 1 H),
7.48–7.55 (m, 2 H), 7.39 (s, 1 H), 6.80 (s, 1 H), 6.54 (d, J ) 5.18
Hz, 1 H), 3.92 (s, 3 H), 3.90 (s, 3 H), 2.52 (s, 3 H). HRMS

1664 Journal of Medicinal Chemistry, 2008, Vol. 51, No. 6
Harmange et al.
(C26H22N3O5)+: calcd, 456.155 40; found, 456.155 48. Anal.
(C26H21N3O5 ·0.5CH3OH) C, H, N.
were separated, and the organic layer was washed with brine, dried
over sodium sulfate, filtered, and concentrated. Purification by silica
gel chromatography (CH3OH in CH2Cl2) or reverse-phase HPLC
provided the title compound (175 mg, 40%) as a white solid. HPLC
6-(6,7-Dimethoxyquinolin-4-yloxy)-N-(3-methylisoxazol-5-yl)-
1-naphthamide (70). The title compound was prepared from 6-(6,7-
dimethoxyquinolin-4-yloxy)-1-naphthoic acid (29a) using a method
analogous to the preparation of compound 6. Yield: 28 mg, 45%.
1
purity: 99% (system A). H NMR (400 MHz, DMSO-d6) δ ppm
8.84 (d, J ) 7.83 Hz, 1 H), 8.51 (d, J ) 5.18 Hz, 1 H), 8.33 (d, J
) 9.22 Hz, 1 H), 8.03 (dd, J ) 6.76, 2.84 Hz, 1 H), 7.87 (d, J )
2.65 Hz, 1 H), 7.56–7.64 (m, 3 H), 7.54 (dd, J ) 9.16, 2.46 Hz, 1
H), 7.44 (s, 1 H), 6.56 (d, J ) 5.18 Hz, 1 H), 4.41–4.61 (m, 1 H),
3.97 (s, 3 H), 3.95 (s, 3 H), 2.22–2.36 (m, 2 H), 2.08 (t, J ) 9.28
Hz, 2 H), 1.60-1.78 (m, 2 H). HRMS (C26H25N2O4)+: calcd,
429.180 88; found, 429.180 33. Anal. (C26H24N2O4 ·H2O) C, H, N.
1
HPLC purity: 95% (system A); 97% (system B). H NMR (400
MHz, DMSO-d6) δ ppm 11.49 (s, 1 H), 8.52 (d, J ) 5.28 Hz, 1
H), 8.37 (d, J ) 9.42 Hz, 1 H), 8.10 (d, J ) 8.33 Hz, 1 H), 7.90
(d, J ) 2.43 Hz, 1 H), 7.72 (d, J ) 6.78 Hz, 1 H), 7.62 (d, J )
14.2 Hz, 1 H), 7.37–7.52 (m, 2 H), 7.41 (s, 1 H), 6.89 (s, 1 H),
6.58 (d, J ) 5.11 Hz, 1 H), 3.95 (s, 3 H), 3.91 (s, 3 H), 2.47 (s, 3
H). HRMS (C26H22N3O5)+: calcd, 456.155 40; found, 456.155 52.
Anal. Calcd for C26H21N3O5: C, 68.56; H, 4.65; N, 9.23. Found:
C, 69.00; H, 4.71; N, 9.13.
N-(5-tert-Butylisoxazol-3-yl)-6-(6,7-dimethoxyquinolin-4-yloxy)-
1-naphthamide (71). The title compound was prepared from 6-(6,7-
dimethoxyquinolin-4-yloxy)-1-naphthoic acid (29a) using a method
analogous to the preparation of compound 6. Yield: 200 mg, 43%.
HPLC purity: 99% (system A). 1H NMR (400 MHz, DMSO-d6) δ
ppm 11.62 (s, 1 H), 8.52 (d, J ) 5.18 Hz, 1 H), 8.37 (d, J ) 9.35
Hz, 1 H), 8.12 (d, J ) 8.46 Hz, 1 H), 7.92 (d, J ) 2.53 Hz, 1 H),
7.82 (d, J ) 6.44 Hz, 1 H), 7.62–7.69 (m, 1 H), 7.55-7.61 (m, 2
H), 7.45 (s, 1 H), 6.83 (s, 1 H), 6.61 (d, J ) 5.43 Hz, 1 H), 3.98
(s, 3 H), 3.95 (s, 3 H), 1.45 (s, 9 H). HRMS (C29H27N3O5Na)+:
calcd, 520.184 29; found, 520.186 63. Anal. (C29H27N3O5) C,
H, N.
N-Cyclopentyl-6-(6,7-dimethoxyquinolin-4-yloxy)-1-naphtha-
mide (75). The title compound was prepared from 6-(6,7-dimethoxy-
quinolin-4-yloxy)-1-naphthoic acid (29a) using a method analogous
to the preparation of compound 6. Yield: 113 mg, 24%. HPLC
purity: 95% (system A); 99% (system C). 1H NMR (400 MHz,
DMSO-d6) δ ppm 8.57 (d, J ) 6.95 Hz, 1 H), 8.51 (d, J ) 4.93
Hz, 1 H), 8.33 (d, J ) 9.09 Hz, 1 H), 7.98–8.05 (m, 1 H), 7.86 (s,
1 H), 7.50–7.65 (m, 4 H), 7.44 (s, 1 H), 6.56 (d, J ) 4.80 Hz, 1
H), 4.26–4.40 (m, 1 H), 3.97 (s, 3 H), 3.95 (s, 3 H), 1.90–2.03 (m,
2 H), 1.50-1.77 (m, 6 H). HRMS (C27H27N2O4)+: calcd, 443.196 53;
found, 443.196 10.
6-(6,7-Dimethoxyquinolin-4-yloxy)-N-propyl-1-naphtha-
mide (76). The title compound was prepared from 6-(6,7-dimethoxy-
quinolin-4-yloxy)-1-naphthoic acid (29a) using a method analogous
to the preparation of compound 6. Yield: 190 mg, 43%. HPLC
N-Cyclopropyl-6-(6,7-dimethoxyquinolin-4-yloxy)-1-naphtha-
mide (72). The title compound was prepared from 6-(6,7-dimethox-
yquinolin-4-yloxy)-1-naphthoic acid (29a) using a method analo-
gous to the preparation of compound 6. The derived amine was
taken up in ethanol and treated with 1 equiv of HCl (1 M in ether)
to provide the hydrochloride salt as a white solid. HPLC purity:
1
purity: 95% (system A). H NMR (400 MHz, DMSO-d6) δ ppm
8.78 (d, J ) 6.44 Hz, 1 H), 8.63 (t, J ) 5.62 Hz, 1 H), 8.44 (d, J
) 9.22 Hz, 1 H), 8.08 (d, J ) 6.06 Hz, 1 H), 8.05 (d, J ) 2.27 Hz,
1 H), 7.81 (s, 1 H), 7.59–7.71 (m, 4 H), 6.90 (d, J ) 6.44 Hz, 1
H), 4.05 (s, 3 H), 4.05 (s, 3 H), 3.31 (q, J ) 6.61 Hz, 2 H),
1.52–1.66 (m, 2 H), 0.96 (t, J ) 7.39 Hz, 3 H). HRMS
(C25H25N2O4)+: calcd, 417.180 88; found, 417.181 36. Anal.
(C25H24N2O4 ·3.5H2O) C, H, N.
1
99% (system A). H NMR (400 MHz, DMSO-d6) δ ppm 8.79 (d,
J ) 6.57 Hz, 1 H), 8.68 (d, J ) 4.29 Hz, 1 H), 8.45 (d, J ) 9.22
Hz, 1 H), 8.07 (d, 2 H), 7.82 (s, 1 H), 7.55–7.71 (m, 4 H), 6.90 (d,
J ) 6.44 Hz, 1 H), 4.06 (s, 6 H), 2.88–3.02 (m, 1 H), 0.69–0.81
(m, 2 H), 0.55–0.65 (m, 2 H). HRMS (C25H23N2O4)+: calcd,
415.165 23; found, 415.164 66. Anal. (C25H22N2O4 ·HCl) C, H, N.
N-(Cyclopropylmethyl)-6-(6,7-dimethoxyquinolin-4-yloxy)-1-
naphthamide (73). To a solution of the acid chloride derived from
acid 29a (120 mg, 0.305 mmol) and NaHCO3 (76.8 mg, 0.914
mmol) in 5 mL of CH2Cl2 was added cyclopropylmethylamine
(0.048 µL, 0.549 mmol). Upon complete consumption of starting
material the reaction was quenched with saturated NaHCO3 (25
mL). The layers were separated, and the aqueous layer was extracted
with CH2Cl2 (2 × 10 mL). The combined organic layers were
washed with brine, dried over sodium sulfate, and filtered.
Concentration in vacuo and purification by silica gel chromatog-
raphy (CH3OH in CH2Cl2) provided the title compound (66 mg,
51% yield) as an off-white solid. HPLC purity: 100% (system A).
1H NMR (400 MHz, DMSO-d6) δ ppm 8.63–8.75 (m, 1 H), 8.49
(d, J ) 5.18 Hz, 1 H), 8.37 (d, J ) 9.22 Hz, 1 H), 7.95–8.10 (m,
1 H), 7.86 (d, J ) 2.40 Hz, 1 H), 7.49–7.65 (m, 4 H), 7.43 (s, 1
H), 6.55 (d, J ) 5.18 Hz, 1 H), 3.96 (s, 3 H), 3.94 (s, 3 H), 3.24
(t, J ) 6.19 Hz, 2 H), 1.03–1.17 (m, 1 H), 0.41–0.53 (m, 2 H),
0.23–0.35 (m, 2 H). HRMS (C26H25N2O4)+: calcd, 429.180 88;
found, 429.181 22. Anal. Calcd for C26H24N2O4: C, 72.88; H, 5.65;
N, 6.54. Found: C, 73.37; H, 5.91; N, 6.40.
6-(6,7-Dimethoxyquinolin-4-yloxy)-N-isopropyl-1-naphtha-
mide (77). The title compound was prepared from 6-(6,7-dimethoxy-
quinolin-4-yloxy)-1-naphthoic acid (29a) using a method analogous
to the preparation of compound 6. Yield: 287 mg, 54%. HPLC
1
purity: 99% (system A). H NMR (400 MHz, DMSO-d6) δ ppm
8.49 (d, J ) 5.18 Hz, 1 H), 8.46 (d, J ) 7.58 Hz, 1 H), 8.33 (d, J
) 9.22 Hz, 1 H), 8.01 (dd, J ) 6.44, 3.16 Hz, 1 H), 7.86 (d, J )
2.53 Hz, 1 H), 7.55–7.62 (m, 3 H), 7.53 (dd, J ) 9.28, 2.59 Hz, 1
H), 7.43 (s, 1 H), 6.54 (d, J ) 5.31 Hz, 1 H), 4.10–4.24 (m, 1 H),
3.96 (s, 3 H), 3.94 (s, 3 H), 1.23 (s, 3 H), 1.21 (s, 3 H). HRMS
(C25H25N2O4)+: calcd, 417.180 88; found, 417.181 32. Anal.
(C25H24N2O4) C, H, N.
N-(4-Chlorophenyl)-6-(6,7-dimethoxyquinolin-4-yloxy)-5-fluoro-
1-naphthamide (78). The title compound was prepared from 6-(6,7-
dimethoxyquinolin-4-yloxy)-5-fluoro-1-naphthoic acid (36a) using
a method analogous to the preparation of compound 42. Yield: 14
mg, 27%. HPLC purity: 99% (system A). 1H NMR (400 MHz,
DMSO-d6) δ ppm 10.83 (s, 1 H), 8.48 (d, J ) 5.18 Hz, 1 H), 8.28
(d, J ) 8.21 Hz, 1 H), 8.17 (d, J ) 8.97 Hz, 1 H), 7.93 (d, J )
6.82 Hz, 1 H), 7.78–7.88 (m, 3 H), 7.65–7.73 (m, 1 H), 7.61 (s, 1
H), 7.47 (s, 1 H), 7.44 (s, 2 H), 6.52 (d, J ) 5.31 Hz, 1 H), 3.97
(d, J ) 1.26 Hz, 6 H). HRMS (C28H21ClFN2O4)+: calcd, 503.116 84;
found, 503.117 04. Anal. (C28H20ClFN2O4 ·0.6CH3OH) C, H, N.
N-Cyclobutyl-6-(6,7-dimethoxyquinolin-4-yloxy)-1-naphtha-
mide (74). Thionyl chloride (10 mL) was added to acid 29a (1.00
mg, 2.67 mmol), and the whole was heated at reflux for 1 h at
which point the mixture was concentrated. The derived solid was
azeotroped with benzene (20 mL) to provide the hydrochloride salt
of the corresponding acid chloride (1.14 g, 100%) as a tan solid
that was used without further purification. To a portion of the
derived acid chloride (400 mg, 0.930 mmol) in 2.5 mL of CH2Cl2
were added DIPEA (810 µL, 4.65 mmol), cyclobutylamine (159
µL, 1.86 mmol), and a crystal of 4-dimethylaminopyridine. Stirring
was continued for 24 h at which point the mixture was diluted with
10 mL of dichloromethane and poured into 1 N NaOH. The layers
N-(4-Chlorophenyl)-7-(6,7-dimethoxyquinolin-4-yloxy)quino-
line-4-carboxamide (79). The title compound was prepared from
7-(6,7-dimethoxyquinolin-4-yloxy)quinoline-4-carboxylic acid (36c)
using a method analogous to the preparation of compound 42. Yield:
1
15 mg, 28%. HPLC purity: 98% (system A); 99% (system B). H
NMR (400 MHz, DMSO-d6) δ ppm 10.95 (s, 1 H), 9.05 (d, J )
3.85 Hz, 1 H), 8.52 (d, J ) 5.05 Hz, 1 H), 8.27 (d, J ) 9.05 Hz,
1 H), 7.77–7.82 (m, 4 H), 7.75 (d, J ) 3.92 Hz, 1 H), 7.62 (d, J )
9.10 Hz, 1 H), 7.48 (d, J ) 8.99 Hz, 1 H), 7.43 (s, 2 H), 6.68 (d,
J ) 4.96 Hz, 1 H), 3.94 (s, 3H), 3.90 (s, 3H). HRMS
(C27H21ClN3O4)+: calcd, 486.121 51; found, 486.121 61.

Naphthamides as Inhibitors
Journal of Medicinal Chemistry, 2008, Vol. 51, No. 6 1665
N-(4-Chlorophenyl)-3-(6,7-dimethoxyquinolin-4-yloxy)iso-
quinoline-8-carboxamide (80). The title compound was prepared
from 3-(6,7-dimethoxyquinolin-4-yloxy)isoquinoline-8-carboxylic
acid (36b) using a method analogous to the preparation of
compound 42. Yield: 14 mg, 27%. HPLC purity: 100% (system
A). 1H NMR (400 MHz, DMSO-d6) δ ppm 10.70 (s, 1 H), 9.28 (s,
1 H), 8.39 (d, J ) 5.05 Hz, 1 H), 7.97–8.05 (m, 1 H), 7.72–7.80
(m, 2 H), 7.65–7.72 (m, 3 H), 7.31 (d, J ) 5.56 Hz, 2 H), 7.28 (d,
J ) 1.39 Hz, 2 H), 6.63 (d, J ) 5.18 Hz, 1 H), 3.80 (s, 3 H), 3.74
(s, 3 H). HRMS (C27H21ClN3O4)+: calcd, 486.121 51; found,
486.121 54. Anal. (C27H20ClN3O4 ·2H2O) C, H, N.
N-(4-Chlorophenyl)-6-(6,7-dimethoxyquinolin-4-ylamino)-1-
naphthamide (81). The title compound was prepared from 6-(6,7-
dimethoxyquinolin-4-ylamino)-1-naphthoic acid (37a) using a
method analogous to the preparation of compound 42. Yield: 94
mg, 49%. HPLC purity: 97% (system A). 1H NMR (400 MHz,
DMSO-d6) δ ppm 10.72 (s, 1 H), 8.98 (s, 1 H), 8.34 (d, J ) 5.35
Hz, 1 H), 8.19 (d, J ) 8.50 Hz, 1 H), 8.01 (d, J ) 8.15 Hz, 1 H),
7.82–8.88 (m, 3 H), 7.70 (s, 1 H), 7.52–7.65 (m, 3 H), 7.40–7.45
(m, 2 H), 7.28 (s, 1 H), 7.01 (d, J ) 5.48 Hz, 1 H), 3.92 (s, 3 H),
3.90 (s, 3 H). HRMS (C28H23ClN3O3)+: calcd, 484.142 25; found,
484.142 97. Anal. (C28H22ClN3O3 ·H2O) C, H, N.
N-(4-Chlorophenyl)-6-((6,7-dimethoxyquinolin-4-yl)(methyl)
amino)-1-naphthamide (82). The title compound was prepared
from 6-((6,7-dimethoxyquinolin-4-yl)(methyl)amino)-1-naphthoic
acid (37b) using a method analogous to the preparation of
compound 6. Yield: 37 mg, 47%. HPLC purity: 96% (system A).
1H NMR (300 MHz, CDCl3) δ ppm 8.62 (s, 1 H), 8.22 (d, J )
5.45 Hz, 1 H), 7.81 (s, 1 H), 7.77 (d, J ) 5.70 Hz, 1 H), 7.58–7.62
(m, 2 H), 7.43 (s, 1 H), 7.41 (t, J ) 4.15 Hz, 1 H), 7.37 (s, 1 H),
7.35 (s, 1 H), 7.29 (s, 1 H), 7.20 (s, 1 H), 7.15–7.19 (m, 2 H), 6.99
(s, 1 H), 4.01 (s, 3 H), 3.64 (s, 3 H), 3.57 (s, 3 H). HRMS
(C29H25ClN3O3)+: calcd, 498.157 90; found, 498.160 01. Anal.
(C29H24ClN3O3 ·H2O) C, H, N.
3500g for 15 min and analyzed on a liquid chromatography tandem
mass spectrometry system consisting of 2 Shimadzu LC-10AD
HPLC pumps and a DGU-14A degasser (Shimadzu, Columbia,
MD), CTC PAL autoinjector (Leap Technologies, Carrboro, NC)
and a API3000 LC-MSMS system. Chromatography was con-
ducted on a Sprite Armor C18 (20 mm × 2.1 mm, 10µm) analytical
column (Analytical Sales and Products, Pompton Plains, NJ) with
a 0.5 µm PEEK guard filter, using the following mobile phase
gradient program: MPA ) H2O with 0.1% formic acid; MPB )
acetonitrile with 0.1% formic acid; 0 min ) 98% MPA, 2% MPB;
0.3 min ) 98% MPA, 2% MPB; 0.7 min ) 5% MPA, 95% MPB;
1.3 min ) 5% MPA, 95% MPB; 1.4 min ) 98% MPA, 2% MPB;
1.7 min ) end of run; approximately 2 min between sample
injections. For each compound, peak areas at each time point
were converted to the natural log of the percentage remaining
relative to the 0 min samples.35 The resulting slope of these values
relative to time (k) was converted to in vitro T1/2 where T1/2
-0.693/k. CLint was calculated using the following relationship:
CLint ) (0.693/T1/2)(1/0.25 mg/mL).
)
Murine KDR (Flk-1) Lung Phosphorylation Assay. Balb/c
female mice were dosed orally with compound 48 at the indicated
doses. Two hours after dosing with 48, 3 µg of murine VEGF was
injected intravenously, and after 5 min the mice were sacrificed
and the lungs were immediately dissected. Blood samples were
collected to determine plasma drug concentrations. Levels of
phosphorylated Flk-1 were subsequently determined by Delphia
assay. Data represent the mean ( standard error. Statistical analysis
was performed by analysis of variance (ANOVA) followed by
Bonferroni-Dunn post hoc test.
In Vivo Vascular Permeability Assay. Vascular permeability
was induced using a modified Miles assay36 and was conducted as
previously described.21
Rat Corneal Angiogenesis Model. Corneal angiogenesis was
evaluated in adult female Sprague–Dawley rats as previously
described.37
Pharmacokinetic Studies. Male Sprague–Dawley rats were
dosed via femoral vein (intravenous, DMSO solution, dose 1 mg/
kg) or via oral gavage (suspensions in OraPlus, pH adjusted to a
range of 2.0–2.2 using methanesulfonic acid, dose 10 mg/kg).
Concentrations of all formulations were selected to allow for dose
volumes in accordance with the highest scientific, humane, and
ethical principals as defined by IACUC (Institutional Animal Care
and Use Committees). Serial blood samples were collected from
jugular vein into heparized tubes over a 12–24 h period. Plasma
was separated by centrifugation, and the sample was prepared for
analysis by protein precipitation with acetonitrile. Quantitation of
the test compounds was accomplished by reverse-phase liquid
chromatography with mass spectral detection in multiple reaction
monitoring mode, with an appropriate internal standard. Pharma-
cokinetic parameters such as clearance, volume of distribution, and
terminal half-life were calculated by a noncompartmental method.
Tumor Xenograft Model. The HT29 cell line was originally
obtained from ATCC. The cells were maintained at 37 °C in DMEM
high glucose/5% FBS, 1× NEAA, 2 mM L-glutamine (Gibco/BRL,
Grand Island, NY) under standard tissue culture conditions. CD1
nu/nu mice within approximately 4–8 weeks of age were challenged
with subcutaneous implants of cultured HT29 human colon cancer
cells (1 × 107 cells per mouse). Eleven days later when tumors
had reached approximately 300 mm3, animals began continuous
daily treatment with compound 48 administered po, qd at the
indicated dose levels. Tumor volumes as established by caliper
measurements were recorded twice per week, along with body
weights as an index of toxicity. Data are expressed as mean values
( standard errors as a function of time. Statistical significance of
observed differences was evaluated by repeated measures analysis
of variance (RMANOVA) followed by Scheffé post hoc testing
for multiple comparisons.
VEGFR-2 Kinase Assay.21 In a 96-well plate, 5 nM/L of either
the phosphorylated or nonphosphorylated form of the VEGFR-2
kinase domain was incubated with compound (10-point titration
ranging from 3 µM to 0.15 nM), 1 µM/L gastrin substrate, 20 mM/L
Tris-HCl, pH 7.5, 10 mM/L MgCl2, 100 mM/L NaCl, 1.5 mM/L
EGTA, 1 mM/L DTT, 0.2 mM/L sodium orthovanadate, and 20
µg/mL BSA for 30 min at 25 °C. ATP was added at a final
concentration of 11.8 µM and incubated for 60 min at room
temperature. Eu-labeled antiphosphotyrosine pT66 antibody (Perkin-
Elmer) was then used for detection.
HUVEC Proliferation Assay.21 Cells were cultured in endot-
helial growth medium-2 (Cambrex). HUVECs were seeded into
flat-bottom, 96-well plates (BD Falcon) at 3000 cells per well in
Dulbecco’s modified Eagle’s medium (DMEM) with 10% fetal
bovine serum (FBS), penicillin, and streptomycin. After culture for
22 h, media were removed and cells were preincubated for 2 h
with serial dilutions of compound diluted 1:400 in DMEM with
10% FBS plus penicillin/streptomycin. HUVECs were then chal-
lenged with 50 ng/mL VEGF or 20 ng/ml bFGF and incubated for
72 h at 37 °C, 5% CO2. Cells were washed twice with Dulbecco’s
phosphate buffered saline (DPBS), and plates were frozen at -70
°C for 24 h. Plates were thawed, incubated with CyQuant dye
(Molecular Probes), and read on a Victor 1420 workstation (Perkin-
Elmer Corporation). IC50 data were calculated using the Levenburg-
Marquardt algorithm in a four-parameter logistic equation (ID
Business Solutions Ltd., Alameda, CA).
In Vitro Metabolism and CLint Calculations. The in vitro
intrinsic clearances, CLint, of the test compounds were determined
by incubations with human and rat liver microsomes purchased from
BD Biosciences (San Jose, CA). The 400 µL incubations contained
0.25 mg of microsomal protein/mL, 1 mM NADPH, 2 mM MgCl2
in 50 mM potassium phosphate buffer, pH 7.4. Test compounds
were added to the prewarmed (37 °C) incubation mixtures at the
final concentration of 1 µM. At 0, 10, 20, 30, and 40 min following
addition of test compound, aliquots of the incubation mixture (35
µL) were collected into an equal volume of acetonitrile + internal
standard (1 µM tolbutamide). The samples were centrifuged at
Covalent Binding Studies. Human and rat liver microsomes (20
mg/mL) were purchased from Xenotech, LLC (Lenexa, KS).
NADPH and glutathione were purchased from Sigma-Aldrich
Chemical Co. (St. Louis, MO). H218O was ordered from Cambridge

1666 Journal of Medicinal Chemistry, 2008, Vol. 51, No. 6
Harmange et al.
Isotope Laboratories Inc. (Andover, MA), and SOLVABLE was
purchased from Perkin-Elmer Life Sciences (Boston, MA).
Supporting Information Available: Tables of elemental analy-
sis, HPLC anlysis, and X-ray data. This material is available free
of charge via the Internet at http://pubs.acs.org.
Microsomal Incubations. 14C compound (10 µM) and liver
microsomes (1 mg/mL) were mixed with 0.1 M potassium
phosphate buffer (pH 7.4) for a final volume of 0.5 mL. The samples
were preincubated at 37 °C for 3 min, and then 1 mM NADPH
was added. The incubations were quenched with 1.0 mL of ice-
cold acetonitrile after 60 min followed by vortex mixing and
centrifugation. The supernatant was dried under a steady stream of
N2 and reconstituted in the initial mobile phase described below.
A 50 µL injection was made using the LCMS method described
below.
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In Vitro Covalent Binding Assay. 14C compound (10 µM) was
again incubated with liver microsomes (1 mg/mL), (()-glutathione
(1 mM), 0.1 M potassium phosphate buffer (pH 7.4), and NADPH
(1 mM) in a final volume of 0.2 mL. The incubations were quenched
with 0.4 mL of ice-cold acetonitrile after 60 min followed by vortex
mixing, centrifugation, and removal of the supernatant. The pellet
was washed three times with 80% methanol, twice with 3:1 ethanol/
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final supernatant was determined by liquid scintillation counting
and was not more than background. The pellet was dried overnight
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scintillation counting.
LCMS Assay. HPLC analyses were carried out on an Agilent
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flow rate of 1 mL/min. The mobile phase consisted of 0.1% formic
acid in water (A) and 0.1% formic acid in acetonitrile (B). The
gradient started at 95% A and linearly ramped to 50% A over 30
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(analyte peak area/IS peak area) versus the theoretical concentrations
of the calibration standards. The percent of binding was calculated
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(concentration of the centrifuged plasma sample) ⁄
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Acknowledgment. We thank our colleagues Loren Berry
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of compound 71, William Buckner for the preparation of
compounds 69 and 70, and Jasmine Lin for helpful discussions
regarding this manuscript.

Naphthamides as Inhibitors
Journal of Medicinal Chemistry, 2008, Vol. 51, No. 6 1667
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