Design, synthesis, and biological evaluation of potent c-Met inhibitors

Article abstract of DOI:10.1021/jm8006189

c-Met is a receptor tyrosine kinase that plays a key role in several cellular processes but has also been found to be overexpressed and mutated in different human cancers. Consequently, targeting this enzyme has become an area of intense research in drug discovery. Our studies began with the design and synthesis of novel pyrimidone 7, which was found to be a potent c-Met inhibitor. Subsequent SAR studies identified 22 as a more potent analog, whereas an X-ray crystal structure of 7 bound to c-Met revealed an unexpected binding conformation. This latter finding led to the development of a new series that featured compounds that were more potent both in vitro and in vivo than 22 and also exhibited different binding conformations to c-Met. Novel c-Met inhibitors have been designed, developed, and found to be potent in vitro and in vivo.

Full text of DOI:10.1021/jm8006189

5766
J. Med. Chem. 2008, 51, 5766–5779
Design, Synthesis, and Biological Evaluation of Potent c-Met Inhibitors
Noel D. D’Angelo,*,† Steven F. Bellon,‡ Shon K. Booker,† Yuan Cheng,† Angela Coxon,§ Celia Dominguez,† Ingrid Fellows,†
Douglas Hoffman,| Randall Hungate,† Paula Kaplan-Lefko,§ Matthew R. Lee,‡ Chun Li, Longbin Liu,† Elizabeth Rainbeau,†
Paul J. Reider,† Karen Rex,§ Aaron Siegmund,† Yaxiong Sun,‡ Andrew S. Tasker,† Ning Xi,† Shimin Xu,† Yajing Yang,§
Yihong Zhang,§ Teresa L. Burgess,§ Isabelle Dussault,§ and Tae-Seong Kim†
Departments of Medicinal Chemistry, Molecular Structure, Oncology Research, Pharmaceutics, and Pharmacokinetics and Drug Metabolism,
Amgen Inc., One Amgen Center DriVe, Thousand Oaks, California 91320-1799
ReceiVed May 23, 2008
c-Met is a receptor tyrosine kinase that plays a key role in several cellular processes but has also been
found to be overexpressed and mutated in different human cancers. Consequently, targeting this enzyme
has become an area of intense research in drug discovery. Our studies began with the design and synthesis
of novel pyrimidone 7, which was found to be a potent c-Met inhibitor. Subsequent SAR studies identified
22 as a more potent analog, whereas an X-ray crystal structure of 7 bound to c-Met revealed an unexpected
binding conformation. This latter finding led to the development of a new series that featured compounds
that were more potent both in vitro and in vivo than 22 and also exhibited different binding conformations
to c-Met. Novel c-Met inhibitors have been designed, developed, and found to be potent in vitro and in
vivo.
Introduction
c-Met is a receptor tyrosine kinase that is normally activated
by binding its natural ligand hepatocyte growth factor, also
known as scatter factor (HGF/SFa). The binding of HGF to
c-Met induces several complex signaling pathways and results
in cell proliferation, motility, migration, and survival.1–3 These
cellular activities are important during normal development and
wound healing but can lead to cancer when the pathway is
deregulated. For example, c-Met has been found to be overex-
pressed or mutated in human cancers, and in many instances,
the overexpression of c-Met has been correlated with advanced
disease stage and poor prognosis.4–7 As a result, c-Met has
attracted considerable attention as a potential target for cancer
treatment.8–10
A variety of approaches have been used to target c-Met. These
include antibody-based therapies,11–14 truncated HGF frag-
ments,15–17 decoy receptors,18 the targeting of the extracellular
c-Met semaphorin domain to prevent dimerization,19 ribozyme-
based treatments,20,21 and small-molecule kinase inhibitors.22–28
Figure 1. Small-molecule c-Met inhibitors and the design of the
Most of the strategies prevent ligand-mediated activation of the
pyrimidone series.
receptor, but small-molecule inhibitors are predicted to inhibit
c-Met activity irrespective of the activation mechanism. This
is significant because it is known that c-Met can be activated
in a ligand-dependent manner as well as in a ligand-independent
manner.6 Therefore, a small-molecule c-Met inhibitor could
benefit a different, and potentially larger, cancer patient
population.
* To whom correspondence should be addressed. Address: One Amgen
Center Drive, Mail Stop 29-2-C, Thousand Oaks, CA 91320-1799. Phone:
805-313-6550. Fax: 805-480-3016. E-mail: dangelo@amgen.com.
†
Department of Medicinal Chemistry.
Department of Molecular Structure.
Department of Oncology Research.
Department of Pharmaceutics.
‡
Several small-molecule c-Met inhibitors have recently been
reported.25 Examples of these include Pfizer’s PF-2341066
(1),26 Sugen’s SU11274 (2),23 and Kirin’s acylthiourea 329
(Figure 1). Compound 3 was of particular interest because
of its reported cellular activity (IC50 ) 8.7 nM in A431 cells).
This led us to consider constrained versions of 3 as possible
c-Met inhibitors. We first examined benzothiazole 4 and
found it to be a potent c-Met inhibitor (c-Met Ki ) 17 nM).
However, its selectivity over other kinases such as kinase
insert domain receptor (KDR), recepteur d’origine nantais
(RON), and insulin-like growth factor receptor (IGFR) was
modest (4- to 13-fold).30 Our replacing the benzothiazole core
with a naphthalene ring system (5) decreased c-Met potency
§
|
Department of Pharmacokinetics and Drug Metabolism.
a Abbreviations: Ac, acetyl; ANOVA, analysis of variance; ATP,
adenosine triphosphate; BSA, bovine serum albumin; DCM, dichlo-
romethane; DMAP, 4-dimethylaminopyridine; DME, 1,2-dimethoxyethane;
DMF, N,N-dimethylformamide; ED, effective dose; HGF, hepatocyte growth
factor; HTRF, homogeneous time-resolved fluorescence; IGFR, insulin-
like growth factor receptor; IP, intraperitoneal injection; iv, intravenous;
KDR, kinase insert domain receptor; LiHMDS, lithium hexamethyldisi-
lazide; NBS, N-bromosuccinimide; PD, pharmacodynamic; PK, pharma-
cokinetic; RON, recepteur d’origine nantais; SAR, structure-activity
relationship; SF, scatter factor; S-Phos, 2-Dicyclohexylphosphino-2′,6′-
dimethoxybiphenyl; TFAA, trifluoroacetic anhydride; TFA, trifluoroacetic
acid; THF, tetrahydrofuran.
10.1021/jm8006189 CCC: $40.75
2008 American Chemical Society
Published on Web 09/03/2008

Potent c-Met Inhibitors
Journal of Medicinal Chemistry, 2008, Vol. 51, No. 18 5767
Scheme 2a
Scheme 1a
a Reagents and conditions: (i) Br2, CHCl3, 0 °C; (ii) 3-fluoro-4-
methoxyphenylboronic acid, Pd(PPh3)4, Na2CO3, DME, H2O, 100 °C, µW;
(iii) HOAc, HBr, 120 °C; (iv) 4-chloro-6,7-dimethoxyquinoline, DMAP,
PhMe, CHCl3, 180 °C; and (v) 2 N NaOH, MeI, 1,4-dioxane, 40 °C.
Scheme 3a
a Reagents and conditions: (i) LiHMDS, DMF, MeI, 0 °C to rt; (ii) Br2,
CHCl3, 0 °C; (iii) 3-fluoro-4-methoxyphenylboronic acid, Pd2(dba)3, S-Phos,
K3PO4, PhMe, 100 °C; (iv) ArylZnCl, Pd(PPh3)4, THF, 60 °C; (v) HOAc,
HBr, 120 °C; (vi) MeSO3H, TFA, reflux; (vii) Cl(CH2)3Br, K2CO3, DMF;
(viii) amine, NaI, K2CO3, DMF, 70 °C; (ix) DMAP, 1,4-dioxane, 110 °C;
(x) pyridine, 1,4-dioxane, 110 °C; (xi) DMAP, 1,4-dioxane, 120 °C, µW;
and (xii) DMAP, pyridine, 1,4-dioxane, 90 °C, µW.
(Ki ) 89 nM) but had little effect on KDR and RON
selectivity (9- and 3-fold, respectively). Greater selectivity,
especially against KDR, was desired to limit potential off-
target toxicity as well as to ensure that any in vivo activity
was a consequence of targeting c-Met. Nevertheless, we were
encouraged by the fact that a conformational restriction of
compound 3 could provide potent c-Met inhibitors.
a Reagents and conditions: (i) NBS, CHCl3; (ii) NaN3, DMF, 0 °C; (iii)
H2, Pd/C, EtOAc, THF; and (iv) RCOCl, Et3N, DCM, 0 °C.
Therefore, we considered an alternative mode of constraining
the acylthiourea moiety of compound 3, which lead to the design
of pyridazine 6 and pyrimidone 7. The former was actually more
potent against KDR (Ki ) 56 nM) and RON (Ki ) 79 nM)
than against c-Met (Ki ) 201 nM) and was therefore not pursued
further. However, 7 was found to inhibit the kinase activity of
c-Met (Ki ) 39 nM) potently. In addition, 7 was selective against
KDR (greater than 30-fold), RON (20-fold), and IGFR (50-
fold). With this promising result, we explored the SAR around
the four main regions of 7 (rings A-D).
Scheme 4a
a Reagents and conditions: (i) Cu, KOH, DMF, pyridine, 110 °C, µW.
Chemistry
Compound 7 served as a convenient intermediate to prepare
analogs that are substituted at the benzylic position. Benzylic
bromination converted 7 into bromide 36, and the subsequent
displacement of this bromide with sodium azide, followed by
hydrogenation, afforded amine 37 as a racemic mixture (Scheme
3). Acylation of this amine under standard conditions afforded
amides 38-40 and urea 41. We prepared two other A-ring
analogs by coupling phenols 12 and 13 to chloride 16 to produce
compounds 42 and 43, with a para-methyl and a para-fluoro
substituent, respectively (Scheme 4).
The synthesis of the N-linked A-ring analogs began with
the demethylation of biaryl 10 to produce phenol 44 (Scheme
5). The displacement of the thiomethyl group under acidic
conditions with different anilines in the microwave produced
phenols 45-47. The coupling of these phenols to either
chloride 16 or 4-chloro-6,7-dimethoxyquinoline produced
compounds 48-51.
The synthesis of the D-ring analogs began with the
alkylation of pyrimidone 831 at the N(3) position to provide
pyrimidone 9 (Scheme 1). Bromination, followed by a Suzuki
coupling with 3-fluoro-4-methoxyphenylboronic acid that
used the palladium-S-Phos complex afforded bicycle 10.32
O-demethylation, followed by the coupling of the methylthi-
opyrimidine moiety to various benzylzinc halides, afforded
phenols 11-13.33 Chlorides 16-21 were prepared in three
routine steps via the debenzylation of quinoline 14,34 the
attachment of the 3-chloropropyl group, and the displacement
of the terminal chloride by the desired amine. Chlorides
16-21 were coupled to phenol 11 in the presence of pyridine
or DMAP to produce analogs 22-27.
The B-ring analogs were prepared next. Bromination of
pyrimidones 28 and 29,35–37 followed by Suzuki coupling to
3-fluoro-4-methoxyphenylboronic acid, afforded methyl ethers
30 and 31 (Scheme 2).38 The removal of the methyl ether under
acidic conditions produced phenols 32 and 33, which were
subjected to SNAr coupling with 4-chloro-6,7-dimethoxyquino-
line to afford analogs 34 and 35. N-methylation of 34 by the
use of sodium hydroxide and methyl iodide afforded compound
7, thereby completing the synthesis of the B-ring set of analogs.
Analogs 55 and 56 were prepared in a slightly different
manner because phenol 44 was first coupled to 4-chloro-6,7-
dimethoxyquinoline to produce intermediate 52 (Scheme 6). The
thiomethyl group was hydrolyzed under oxidative conditions
by the use of urea hydrogen peroxide in acetonitrile and TFA
to produce 53. The resultant hydroxyl moiety was converted to

5768 Journal of Medicinal Chemistry, 2008, Vol. 51, No. 18
D’Angelo et al.
Scheme 5a
60. This was converted to phenol 61 in two steps and was then
coupled to chloride 16 to afford 62.
Results and Discussion
SAR and Lead Generation. The enzyme activity of 7
supported our hypothesis that the pyrimidone series could afford
good enzyme potency against c-Met. To facilitate subsequent
SAR studies, we examined the X-ray structure of a cocrystal
of 7 bound to c-Met (Figure 2). This X-ray revealed that 7
occupies the ATP binding site of c-Met. As a result, 7 can be
assumed to be an ATP-competitive inhibitor of c-Met. In
addition, the benzyl moiety of 7 (ring A) fits into a hydrophobic
pocket that is formed by ILE1145 at the back end, which we
refer to as the ILE1145 binding pocket. This pocket could be
probed with different phenyl substituents to improve potency.
Also, the benzyl position is orientated toward a channel in the
c-Met backbone, which suggests that benzyl substituents could
fit into this channel and provide additional interactions with
c-Met.
a Reagents and conditions: (i) HOAc, HBr, 120 °C; (ii) RNH2, concd
HCl, 120 °C, µW; (iii) 4-chloro-6,7-dimethoxyquinoline, DMAP, 1,4-
dioxane, 120 °C, µW; and (iv) 16, Cu, KOH, DMF, pyridine, 110 °C, µW.
Scheme 6a
In terms of the pyrimidone B ring, the X-ray revealed that
the carbonyl is twisted away from the Asp1222 residue and
directly forms a hydrogen bond with Lys1110. As a result, the
polar Asp1222 residue is presented with the hydrophobic C-H
group of the B ring, which suggests a potential energy penalty.
In addition, there is a fairly tight steric environment around the
B and C rings; therefore, we expected SAR opportunities here
to be more limited.
The quinoline portion (ring D) on the left side forms hydrogen
bonds with the Pro1158 and Met1160 residues and also
maintains van der Waals interactions with the c-Met backbone.
In addition, this quinoline system is directed toward a solvent-
exposed area, which provides an opportunity for the introduction
of polar, water-solubilizing groups. We began our optimization
studies of 7 here.
The introduction of a carbon tether, which contains different
tertiary amines, off of the quinoline D-ring was examined first.
A three-carbon tether between these amines and the quinoline
had previously been determined to be the optimal length for
improving the potency; therefore, we examined different amines
at the end of this tether.40,41 All of the amines improved the
c-Met enzyme relative to 7, a finding that can be explained by
the van der Waals interactions that are gained between the
carbon tether and the c-Met backbone (Table 1). Of these
amines, the morpholine (22) and N-methylpyrazine (25) deriva-
tives afforded the greatest increase in potency.
a Reagents and conditions: (i) 4-chloro-6,7-dimethoxyquinoline, DMAP,
pyridine, 1,4-dioxane, 110 °C; (ii) urea hydrogen peroxide, TFA, MeCN, 0
°C; TFAA, 0 °C to rt; (iii) POCl3, N,N-dimethylaniline, 125 °C to rt; and
(iv) RNH2, concd HCl, 1,4-dioxane, 60 °C, µW.
Scheme 7a
Substitutions of the B-ring pyrimidone core were explored
next (Table 2). The removal of the N-methyl group (34) reduced
enzyme potency by about 3-fold, whereas the introduction of a
methyl group at the 6-position (35) lowered the potency by an
additional factor of 5. Overall, these two changes reduced the
potency more than 10-fold, which supports the hypothesis that
this portion of the molecule is sensitive to substitution. In view
of these results, we did not pursue further SAR studies around
the pyrimidone core or on the fluorophenyl C ring.
We conducted SAR studies to explore different substituents
at the benzyl position and on the phenyl A ring. For the former,
the X-ray cocrystal structure of 7 (Figure 2) suggested that
substituents could gain van der Waals interactions with a channel
in the c-Met backbone, thereby improving potency. In addition,
because this channel was solvent accessible, polar substituents
were considered. However, amine 37, amides 38-40, and urea
41 provided little improvement in potency (Table 3). In fact,
41 decreased the potency by about 10-fold. Overall, these results
a Reagents and conditions: (i) NaH, BnBr, DMF, 0 °C to rt; (ii) Pd(PPh3)4,
t-BuOC(O)CH2ZnCl, THF, 60 °C; (iii) TFA, DCM, 0 °C to rt; (iv) (COCl)2,
DCM, DMF; 59, Et3N, 0 °C to greater than rt; (v) 4-fluoroaniline, concd
HCl, 1,4-dioxane, 125 °C; (vi) BBr3, DCM; and (vii) 16, DMAP, pyridine,
1,4-dioxane, 130 °C.
the corresponding chloride 54 by the use of POCl3. The
subsequent displacement of the chloride with different amines,
again under acidic conditions in the microwave, produced
analogs 55 and 56.
We prepared C-ring pyridine analog 62 by beginning with
the protection of commercially available 6-bromopyridin-3-ol
as benzyl ether 57 (Scheme 7). Negishi coupling to 2-tert-
butyoxy-2-oxoethylzinc chloride, followed by TFA hydrolysis,
afforded acid 58.39 The conversion of 58 to the corresponding
acyl chloride, followed by the addition of 59 and Et3N, produced

Potent c-Met Inhibitors
Journal of Medicinal Chemistry, 2008, Vol. 51, No. 18 5769
Figure 2. X-ray cocrystal of 7 bound to c-Met.
Table 1. c-Met Enzyme Activity of Analogs 22-27a
Table 2. c-Met Enzyme Activity of B-Ring Analogs 7, 34, and 35a
compd
R
R′
Ki (nM)b
7
34
35
H
H
Me
Me
H
H
39 ( 6
107 ( 4
489 ( 74
a See the Experimental Section for assay details. b Average of four
experiments.
Table 3. c-Met Enzyme Activity of Benzyl-Substituted A-Ring
Analogsa
compd
R
Ki (nM)b
7
H
NH2
39 ( 6
72 ( 11
30 ( 5
71 ( 14
52 ( 11
368 ( 55
37
38
39
40
41
NH(CO)CH2NMe2
NH(CO)CH2CH3
NH(CO)CH2CH2SCH3
NH(CO)NMe2
a See the Experimental Section for assay details. b Average of four
experiments.
a See the Experimental Section for assay details. b Average of four
experiments.
to improve the potency further, we next considered replacing
the carbon linkage between the A and B rings with a nitrogen
atom. This change would allow for an additional hydrogen bond
to be gained with Phe1223 (adjacent to Asp1222, Figure 2),
potentially via a bridging water molecule, thereby improving
enzyme potency.
To test this hypothesis, N-phenyl analog 48 was synthesized,
and the SAR around the phenyl A ring was explored (Table 5).
Our replacing the carbon linkage with a nitrogen linkage actually
reduced the enzyme potency to a small extent, as a comparison
of compounds 7 and 48 indicates. The introduction of a fluoro
group at the ortho or meta position had a minimal impact on
enzyme potency. However, substitution at the para position
increased the potency because the 4-fluoro derivative (50) has
a binding affinity of 14 nM. Larger groups at this position (e.g.,
suggested that whereas the benzyl substitution could certainly
be tolerated, no obvious benefit was gained from it.
In terms of the phenyl ring SAR, two additional analogs were
made that incorporated different substituents at the para position
(Table 4). These compounds had enzyme potencies that were
similar to that of 22, which suggests that small substituents were
well tolerated at this position. Because these compounds had
enzyme potencies that were similar to that of 22 and also
because SAR studies on the nitrogen-linked A rings (see Table
5) indicated that these substituents provided the best increase
in potency, further SAR studies were not pursued.
N-Phenyl Analogs. To this point, the most potent compounds
exhibited a Ki of around 10 nM in the enzyme assay. However,

5770 Journal of Medicinal Chemistry, 2008, Vol. 51, No. 18
Table 4. c-Met Enzyme Activity of A-Ring Analogs 42 and 43a
D’Angelo et al.
compd
R
Ki (nM)b
22
42
43
H
Me
F
8.9 ( 1.3
9.6 ( 0.7
17 ( 2
a See the Experimental Section for assay details. b Average of four
experiments.
Figure 3. X-ray cocrystal of 50 bound to c-Met.
Table 5. c-Met Enzyme Activity of N-Phenyl A-Ring Analogsa
the formation of an additional hydrogen bond with c-Met. A
comparison of Figures 2 and 3 reveals that the A and C rings
of both compounds adopt the same orientation relative to the
c-Met backbone. Therefore, the conformational preferences of
these two compounds dictate their respective pyrimidone B-ring
orientations and hence their binding conformations to the
protein. The additional hydrogen bond that was gained as a result
of the changed pyrimidone conformation and the introduc-
tion of the para-fluoro substituent are the most plausible
explanations of the increase in potency that was observed with
nitrogen-linked compounds (e.g., 50 and 51) compared with
carbon-linked compounds (e.g., 7). It should be noted that 50,
like 7, binds to c-Met in the ATP pocket which indicates that
50 is an ATP-competitive inhibitor. This conclusion can also
be applied to other pyrimidone molecules such as 22 and 51
because of their structural similarities to 7 and 50, respectively.
The X-ray cocrystal of 50 also provided another clue as to
how enzyme potency could be further improved. The dihedral
angle between the fluorophenyl C ring and the pyrimidone B
ring is 18°. To determine whether this dihedral angle corre-
sponds to an energetically favored conformation, we examined
an energy diagram that used 5-phenylpyrimidone as a surrogate
for the B and C rings (Figure 4, top). As this graph indicates,
a dihedral angle of 18° is about 1.5 kcal/mol above the energy
minimum, which suggests that compounds like 50 and 51 incur
a significant energy penalty to adopt the conformation with
which they bind to c-Met.
a See the Experimental Section for assay details. b Average of four
experiments.
To eliminate this energy barrier, we envisioned replacing the
fluorophenyl C ring with a pyridine ring on the basis of the
energy diagram of pyridin-2-yl pyrimidone (Figure 4, bottom).
This diagram suggests that for a pyridine ring a dihedral angle
of 20° or less provides the lowest energy conformation, which
is in contrast with the phenylpyrimidone systems in which such
a dihedral angle is energetically disfavored. As a result, we
expected analogs with a pyridine B ring to be more potent
because of the low-energy barrier that is required for them to
bind c-Met. On the basis of this reasoning, we examined analog
62 and found it to be one of the most potent analogs of the
series thus far (Ki ) 3.4 ( 0.7 nM). However, the increase in
potency compared with that of 51 (Ki ) 4.9 nM) was virtually
negligible, at least in the enzyme assay. This could be the result
of removing the C-ring fluoro group, a change that could offset
any gain in potency that was obtained by the use of the pyridine
ring.
56) decreased the potency, which suggests that the substitution
at this position is fairly sensitive to a substituent’s steric size.
Having determined that the 4-fluoro group provided the best
potency for the N-phenyl A ring we decided to reintroduce the
morpholine tail off of the quinoline D ring to improve the
potency further. Toward this end, analog 51 was prepared and
was found to be about 3 times more potent than both 50 and
carbon-linked analog 43, which indicates that our changing the
carbon linkage to a nitrogen linkage has a beneficial impact on
enzyme activity.
An X-ray cocrystal structure of 50 provided some insight into
this observation (Figure 3). Surprisingly, the binding conforma-
tion of 50 differed significantly from that of 7. Most notably,
the pyrimidone carbonyl of 50 forms a direct hydrogen bond
with the backbone of Asp1222, whereas C-linked analog 7 has
its carbonyl pointed toward the Lys1110 primary amine (Figure
2). In addition, the N(1) pyrimidone nitrogen of 50 is bridged
to Lys1110 through hydrogen bonding to a crystallographically
resolved water molecule, which indirectly preserves the hydro-
gen bond between the pyrimidone carbonyl of 7 and this amino
acid. Therefore, the different pyrimidone orientation results in
In Vitro Cell Assays. Some of the more potent compounds
that were identified in the enzyme assay were tested for their
ability to inhibit HGF-mediated c-Met phosphorylation in PC3
cells, a human prostate cancer cell line, and CT26 cells, a murine

Potent c-Met Inhibitors
Journal of Medicinal Chemistry, 2008, Vol. 51, No. 18 5771
Table 7. Enzyme Selectivity of Key Compoundsa
c-Met Ki
KDR Ki
Ron Ki
IGFR Ki
compd
(nM)b
(nM)c,d
(nM)e,f
(nM)f
7
39
8.9
17
14
4.9
3.4
>1300
422
>3000
581
195
706
80
28
1.3
1030
1450
860
70
22
51
22
43
50
51
62
382
139
83
a See the Experimental Section for assay details. b Average of four
experiments. c Value is the result of a single measurement, with the exception
of 22, which is the average of two experiments. d Phosphorylated KDR.
e Phosphorylated Ron. f Value is the result of a single experiment.
Figure 4. Torsional profiles of 5-phenyl pyrimidone (top) and pyridin-
2-yl pyrimidone (bottom) for the dihedral angle highlighted in red. The
coplanar structures shown are defined with a dihedral angle of 0°.
Energy profiles were calculated on the basis of gas-phase quantum
mechanic calculations by the use of density functional theory.
Table 6. IC50 Values of Lead Analogs Against PC3 and CT26 Cell
Linesa
Figure 5. Effect of 22 and 51 on HGF-mediated c-Met phosphorylation
at 2 h postdose. Asterisk denotes p < 0.0001 compared with the HGF
group (black bar). Bars represent the mean ( standard deviation (n )
3). Circles represent mean plasma concentration ( standard deviation.
compd
Ki (nM)b
PC3 IC50 (nM)b
CT26 IC50 (nM)b
7
39
17
4.9
3.4
313
161
64
368
196
82
43
51
62
39
59
The selectivities of compounds 22, 51, and 62 were also
examined against a larger panel of tyrosine kinases and serine/
threonine kinases. In this panel, the three compounds exhibited
low selectivity (less than 10-fold) against only a small number
of kinases (LCK, BTK, and cFMS). For most of the other
examined kinases, selectivities were greater than 100-fold.42
In Vivo Studies. Compound 22 from the carbon-linked series
and compounds 51 and 62 from the nitrogen-linked series were
evaluated for their pharmacokinetic (PK) properties and phar-
macodynamic (PD) effects. All three compounds exhibited good
PK profiles when they were given intravenously (iv) to rats,
with half lives that ranged from 2.4 to 4 h, volumes of
distribution that ranged from 3.0 to 5.4 L/kg, and clearances
that ranged from 0.56 to 1.9 L/h/kg. Compound 22 had the
highest bioavailability with a value of 100%, whereas 51 and
62 had values of 34 and 48%, respectively. Given the promising
PK profiles of these compounds, we decided to evaluate all three
compounds in a PD assay.
a See the Experimental Section for assay details. b Average of four
experiments, with the exception of the PC3 and CT26 values for 62, which
are the average of two experiments.
cell line that is derived from a colon carcinoma (Table 6). In
general, the compounds were slightly more potent in PC3 cells
than they were in CT26 cells. In addition, the compounds
generally exhibited a 10-fold shift in potency from enzyme to
cell. Most significantly, the trends observed for enzyme potency
for these compounds correlated with those that were observed
for their cellular activities. Thus, the conversion of 7 to 43
resulted in improved cell potency as well as improved enzyme
potency. Our changing the carbon linkage of 43 to a nitrogen
linkage (51) improved enzyme and cellular potencies by an
additional factor of 3. Finally, our replacing the fluorophenyl
C ring of 51 with a pyridine ring (62) further improved cellular
potency and made 62 the most potent analog that was prepared
in this series.
These compounds were administered to mice by either oral
gavage (PO) or intraperitoneal injection (IP) (10, 30, or 100
mg/kg). Recombinant human HGF was injected iv at 2 h
postdose. Livers were then harvested, and c-Met phosphorylation
was quantified. Treatment with 22, 51, and 62 led to the dose-
dependent inhibition of c-Met phosphorylation (Figures 5 and
6). Compound 22 exhibited an ED90 of approximately 100 mg/
kg (Figure 5). Consistent with the enzyme and cell data, analogs
51 and 62 exhibited increased potencies, with ED90 values of
∼30 mg/kg (Figures 5 and 6).
Enzyme Selectivity. The selectivity of certain compounds
against KDR, RON, and IGFR was examined next, and the
results are outlined in Table 7. A noticeable trend is that the
carbon-linked compounds (7, 22, and 43) were more selective
against these enzymes than were the nitrogen-linked compounds
(50, 51, and 62). This result might be explained by the
differences in binding conformations that are demonstrated by
7 (Figure 2) and 50 (Figure 3). In particular, the different
selectivity profiles most likely are the result of the different
pyrimidone orientations because the A and C rings virtually
occupy the same space in both cases. Whereas the decrease in
selectivity was undesirable, the selectivity, especially that against
KDR, was still high enough for 51 and 62 to justify further in
vivo studies on these compounds, as well as on 22.
Conclusions
Overall, we have developed a novel and potent chemical
series for targeting c-Met in vitro and in vivo. Our initial lead

5772 Journal of Medicinal Chemistry, 2008, Vol. 51, No. 18
D’Angelo et al.
the use of UV detection at 254 nm. High-resolution MS measure-
ments were obtained by the use of electrospray ionization on a
Thermo Scientific linear ion trap (LTQ) Orbitrap spectrometer.
Elemental Analyses (C, H, N) were obtained from Atlantic
Microlab in Norcross, Georgia.
3-Methyl-2-(methylthio)pyrimidin-4(3H)-one (9). Compound
8 (6.29 g, 44.2 mmol) was suspended in DMF (100 mL) and was
cooled to 0 °C, and additional DMF (50 mL) was added. Solid
LiHMDS (9.58 g, 57.3 mmol) was added in one portion, and the
reaction was stirred at 0 °C. MeI (3.6 mL, 57.8 mmol) was added
via syringe, and the reaction was warmed to room temperature and
was stirred for 20.75 h. At this time, it was poured into 300 mL of
H2O and was extracted exhaustively with EtOAc. The organic
extracts were combined, were dried over Na2SO4, were filtered,
were concentrated, and were purified on silica gel (3:1 f 3:2 f
1
1:1 hexanes/EtOAc) to produce 9 (3.79 g, 55%). H NMR (400
MHz, CDCl3, δ): 7.76 (d, J ) 6.4 Hz, 1H), 6.20 (d, J ) 6.4 Hz,
1H), 3.52 (s, 3H), 2.58 (s, 3H). MS (ES) m/z: 157 (M + H+).
5-(3-Fluoro-4-methoxyphenyl)-3-methyl-2-(methylthio)pyri-
midin-4(3H)-one (10). Compound 9 (3.31 g, 21.2 mmol) was
dissolved in chloroform (50 mL) and was cooled to 0 °C under
argon. Bromine (1.25 mL, 25.4 mmol) was added via syringe, and
the reaction was stirred at 0 °C for 35 min, at which time TLC
analysis indicated the complete consumption of starting material.
The reaction was quenched with 40 mL of saturated NaHCO3, was
warmed to room temperature, and was stirred overnight. The
reaction was extracted with DCM (3 × 25 mL), and the organic
extracts were combined, were dried over Na2SO4, were filtered,
and were concentrated to produce 5-bromo-3-methyl-2-(methylthi-
o)pyrimidin-4(3H)-one (4.98 g, 100%), which did not require further
purification. 1H NMR (400 MHz, CDCl3, δ): 8.07 (s, 1H), 3.58 (s,
3H), 2.58 (s, 3H). MS (ES) m/z: 235 (Br79, M + H+), 237 (Br81,
M + H+).
5-Bromo-3-methyl-2-(methylthio)pyrimidin-4(3H)-one (14.77 g,
62.8 mmol), 3-fluoro-4-methoxyphenylboronic acid (20.11 g, 118.3
mmol), Pd2(dba)3 (1.869 g, 2.04 mmol), S-Phos (3.45 g, 8.40 mmol),
and K3PO4 (42.27 g, 199.1 mmol) were suspended in PhMe (200
mL). Argon was bubbled through the solution for 5 min, and the
reaction was then placed in a preheated oil bath (100 °C) and was
stirred for 6.25 h, at which time LCMS analysis indicated a
complete reaction. The reaction was cooled to room temperature
and was allowed to stand overnight. It was then diluted with DCM
(200 mL) and was filtered through a 1in plug of silica gel that was
washed exhaustively with MeOH, EtOAc, and DCM. (Some solid
material that was stuck in the flask had to be taken up in water and
extracted with EtOAc separately). The filtrate (and EtOAc extracts)
were combined and concentrated, which resulted in an orange solid.
This was treated with hexanes and was filtered, and the resultant
light-yellow solid was repeatedly washed with hexanes and was
dried under high vacuum to afford 10 (15.85 g, 90%) as a light-
yellow solid. For analytical purposes, a sample was washed with
EtOAc, and the resultant white solid was dried under vacuum. 1H
NMR (400 MHz, CDCl3, δ): 7.93 (s, 1H), 7.46 (d, J ) 12.8 Hz,
1H), 7.40 (d, J ) 8.8 Hz, 1H), 6.99 (t, J ) 8.8 Hz, 1H), 3.94 (s,
3H), 3.59 (s, 3H), 2.61 (s, 3H). MS (ES) m/z: 281 (M + H+).
General Procedure for the Synthesis of 11-13. 2-Benzyl-5-
(3-fluoro-4-hydroxy-phenyl)-3-methylpyrimidin-4(3H)-one (11).
To a 500 mL three-necked round-bottomed flask that contained 10
(10 g, 36 mmol) and Pd(PPh3)4 (4.5 g, 3.9 mmol) in THF (50 mL)
was added benzylzinc bromide (100 mL, 0.5 M in THF, 42 mmol).
The flask was then placed in a preheated (60 °C) oil bath, and the
reaction was stirred for 2 h and was then allowed to cool to ambient
temperature. The reaction was quenched with saturated NH4Cl,
DCM (300 mL) was added, and the mixture was stirred overnight.
The layers were separated, and the organic phase was collected,
was dried over Na2SO4, was filtered, and was concentrated.
The crude material was put in a 1000 mL three-necked round-
bottomed flask, and acetic acid (140 mL, 31 mmol) and hydrobro-
mic acid (340 mL, 48%, 31 mmol) were added. The flask was fit
with a reflux condensor, and the mixture was stirred at 135 °C for
4 h. The mixture was filtered while it was still hot, and the filtrate
Figure 6. Effect of 62 on HGF-mediated c-Met phosphorylation at
2 h postdose. Asterisk denotes p < 0.0001 compared with the HGF
group (black bar). Bars represent the mean ( standard deviation (n )
3). Circles represent mean plasma concentration ( standard deviation.
compound 7 was found to be a potent c-Met inhibitor and was
subsequently developed into the more potent analog 22.
However, an X-ray crystal structure of 7 bound to c-Met
revealed an unexpected binding conformation. This result led
to the design and synthesis of nitrogen-linked A-ring analogs
50 and 51, which were more potent than 22 both in vitro and
in vivo but were also less selective against other enzymes. The
X-ray crystal structure of 50 revealed a binding conformation
that was different from that of the carbon-linked analogs. This
finding helps explain the potency and enzyme selectivity
differences between the two series. This X-ray structure led to
the design and synthesis of pyridine analog 62 as a means of
minimizing dihedral angle strain between the B and C rings.
As a result, 62 proved to be the most potent compound in this
series both in vitro and in vivo.
Experimental Section
Chemistry. All reactions were conducted on the benchtop and
were run under nitrogen by the use of a Teflon-coated magnetic
stir bar at the indicated temperature. Reactions that were run at an
elevated temperature were run in an oil bath at the indicated
temperature. Microwave reactions were run in a CEM Discover
microwave that was equipped with the PowerMAX feature that used
the settings described below. All solvents and reagents that were
obtained from commercial sources were used without further
purification. The removal of solvents was conducted by the use of
a rotary evaporator, and the residual solvent was removed from
nonvolatile compounds by the use of a vacuum manifold that was
maintained at ∼1 torr. All reported yields are isolated yields.
Analytical TLC was performed with EMD 0.25 mm silica gel
60 plates with a 254 nm fluorescent indicator. Plates were developed
in a covered chamber and were visualized with ultraviolet light.
Flash chromatography refers to column chromatography, as de-
scribed by Still, that uses EMD silica gel 60 (230-400 mesh) as
the stationary phase.43 ISCO purification refers to a Teledyne ISCO
purification system that uses RediSep columns in the size that is
noted as well as the solvent system and gradients that are noted.
1H NMR spectra were obtained on a Bruker BioSpin GmbH
magnetic resonance spectrometer. 1H NMR spectra are reported
as chemical shifts in parts per million (ppm) relative to an internal
solvent reference. Peak multiplicity abbreviations are as follows: s
(singlet), br s (broad singlet), d (doublet), dd (doublet of doublets),
t (triplet), q (quartet), qn (quintet), and m (multiplet).
We conducted analytical HPLC and mass spectroscopy by the
use of a reverse-phase Agilent 1100 series HPLC-MS by using
the methods that are noted for each compound in the Supporting
Information. The retention time (tR) was recorded in minutes by

Potent c-Met Inhibitors
Journal of Medicinal Chemistry, 2008, Vol. 51, No. 18 5773
was cooled to ambient temperature. The filtrate was filtered, and
under DMSO peak), 2.04-1.97 (m, 2H), 1.73-1.65 (m, 4H). MS
(ES) m/z: 595 (M + H+). HRMS calcd for C35H36FN4O4 (M +
the solid that was collected was washed with hexanes to afford 11
1
(9.2 g, 82% over two steps) as an off-white solid. H NMR (400
H+), 595.2721; found, 595.2712. Analytical HPLC: 97.9%. tR
)
MHz, CDCl3, δ): 8.05 (s, 1H), 7.52 (dd, J ) 12.1, 2.0 Hz, 1H),
7.40-7.21 (m, 6H), 7.00 (t, J ) 8.8 Hz, 1H), 6.20 (br s, 1H), 4.20
(s, 2H), 3.51 (s, 3H). MS (ES) m/z: 311 (M + H+).
5.47.
5-(4-(7-(3-(1H-1,2,4-Triazol-1-yl)propoxy)-6-methoxyquinolin-
4-yloxy)-3-fluorophenyl)-2-benzyl-3-methylpyrimidin-4(3H)-
one (24). By using chloride 18, we prepared compound 24 by
following the procedure that was used to prepare 22, with the
following modifications: pyridine (2.5 mL) and 1,4-dioxane (1.25
mL) were both used, and the reaction was run in the microwave at
90 °C and 150 W for 10 min. Compound 24 was isolated in 3%
yield as an off-white solid. 1H NMR (400 MHz, d6-DMSO, δ):
8.57 (s, 1H), 8.50 (d, J ) 5.3 Hz, 1H), 8.29 (s, 1H), 7.99 (s, 1H),
7.92 (dd, J ) 12.5, 1.6 Hz, 1H), 7.74 (d, J ) 8.3 Hz, 1H), 7.55 (s,
1H), 7.51 (t, J ) 8.8 Hz, 1H), 7.41-7.25 (m, 6H), 6.52 (d, J ) 5.3
Hz, 1H), 4.41 (t, J ) 6.9 Hz, 2H), 4.28 (s, 2H), 4.18 (t, J ) 6.0
Hz, 2H), 3.97 (s, 3H), 3.52 (s, 3H), 2.41-2.30 (m, 2H). MS (ES)
m/z: 593 (M + H+). HRMS calcd for C33H30FN6O4 (M + H+),
593.2313; found, 593.2299. Analytical HPLC: 96.8%. tR ) 5.22.
2-Benzyl-5-(4-(7-(3-(4-ethylpiperazin-1-yl)-propoxy)-6-meth-
oxyquinolin-4-yloxy)-3-fluorophenyl)-3-methylpyrimidin-4(3H)-
one (26). By using chloride 20, and by following the procedure
that was used to prepare 24, we obtained 26 (10%) as a white solid.
1H NMR (400 MHz, d6-DMSO, δ): 8.50 (d, J ) 5.1 Hz, 1H), 8.29
(s, 1H), 7.92 (d, J ) 12.6 Hz, 1H), 7.74 (d, J ) 8.7 Hz, 1H), 7.53
(s, 1H), 7.50 (t, J ) 12.0 Hz, 1H), 7.42-7.25 (m, 6H), 6.51 (d, J
) 4.7 Hz, 1H), 4.28 (s, 2H), 4.19 (t, J ) 5.8 Hz, 2H), 3.95 (s, 3H),
3.52 (s, 3H), 2.61-2.30 (m, 12H), 2.05-1.90 (m, 2H), 0.99 (t, J
) 7.0 Hz, 3H). MS (ES) m/z: 638 (M + H+). HRMS calcd for
C37H41FN5O4 (M + H+), 638.3143; found, 638.3135. Analytical
HPLC: 97.5%. tR ) 4.70.
4-Chloro-6-methoxyquinolin-7-ol (15). 7-(Benzyloxy)-4-chloro-
6-methoxyquinoline (36 g, 0.11 mol) was dissolved in TFA (200
mL), and CH3SO3H (13.9 mL, 0.214 mol) was added in one portion.
The reaction was heated at reflux for 3 h and was then cooled to
room temperature and concentrated. Aqueous 2.5 N NaOH was
added to raise the pH of the solution to 7, which caused
precipitation. The resultant solid was crushed, was stirred vigorously
for 1 h, and was then filtered. The solid was collected and was
dried under high vacuum to afford 15 (22 g, ∼100%) as a brown
1
solid. H NMR (400 MHz, d6-DMSO, δ): 8.66 (d, J ) 5.0 Hz,
1H), 7.64 (d, J ) 5.0 Hz, 1H), 7.42 (s, 1H), 7.40 (s, 1H), 4.00 (s,
3H), 2.31 (s, 1H). MS (ES) m/z: 210 (M + H+).
General Procedure for the Synthesis of 16-21. 4-Chloro-6-
methoxy-7-(3-morpholino-propoxy)quinoline (16). Compound 15
(11 g, 53 mmol), 3-chloro-1-bromopropane (26 mL, 265 mmol),
and K2CO3 (69 g, 500 mmol) were suspended in DMF (400 mL)
and were stirred at room temperature for 16 h. The suspension was
filtered, and the filtrate was concentrated and diluted with EtOAc
and water. The organic layer was separated, was dried over Na2SO4,
was filtered, and was concentrated to afford a brown solid, which
was directly used in the next step.
This brown solid was diluted with DMF (800 mL) and NaI (11.8
g, 79 mmol), and K2CO3 (36 g, 265 mmol) and morpholine (27.7
mL, 318 mmol) were added. The reaction was heated to 70 °C and
was stirred for 16 h. It was then cooled to room temperature, was
diluted with water (2 L), and was extracted two times with EtOAc.
The organic extracts were combined, were dried over sodium
sulfate, were filtered, and were concentrated to produce a dark-
brown solid. This material was recrystallized in DCM-hexanes to
General Procedure for the Synthesis of 25 and 27. 2-Benzyl-
5-(3-fluoro-4-(6-methoxy-7-(3-(4-methylpiperazin-1-yl)pro-
poxy)quinolin-4-yloxy)phenyl)-3-methylpyrimidin-4(3H)-
one (25). Phenol 11 (258 mg, 0.832 mmol), chloride 19 (350 mg,
0.999 mmol), and DMAP (10 mg, 0.083 mmol) were suspended in
pyridine (4.0 mL) and 1,4-dioxane (1.0 mL) and were heated in an
oil bath at 110 °C over the weekend, at which time the solvent
evaporated. More pyridine and 1,4-dioxane were added, and stirring
was continued until about half of the starting material had been
consumed, according to LCMS analysis. The reaction was cooled
to room temperature, was concentrated, and was purified on silica
gel (0 f 10% 2 M ammonia in MeOH/DCM). The fraction with
product was collected, was concentrated, and was purified by HPLC.
The fraction with product was treated with ammonium hydroxide
and was extracted with 5% MeOH/DCM. The organic extracts were
washed with saturated NaHCO3, were dried over sodium sulfate,
were filtered, and were concentrated to afford 25 (40 mg, 8%) as
1
afford 16 (12 g, 67% over two steps) as a light-brown solid. H
NMR (400 MHz, d6-DMSO, δ): 8.60 (d, J ) 4.5 Hz, 1H), 7.55 (d,
J ) 4.5 Hz, 1H), 7.45 (s, 1H), 7.37 (s, 1H), 4.21 (t, J ) 6.3 Hz,
2H), 3.97 (s, 3H), 3.60-3.55 (m, 4H), 2.46 (t, J ) 7.0 Hz, 2H),
2.41-2.35 (m, 4H), 1.97 (qn, J ) 6.0 Hz, 2H). MS (ES) m/z: 337
(M + H+).
General Procedure for the Synthesis of 22-24 and 26.
2-Benzyl-5-(3-fluoro-4-(6-methoxy-7-(3-morpholinopropoxy)quin-
olin-4-yloxy)phenyl)-3-methylpyrimidin-4(3H)-one (22). Phenol
11 (200 mg, 0.645 mmol), chloride 16 (261 mg, 0.774 mmol), and
DMAP (24 mg, 0.20 mmol) were suspended in 1,4-dioxane in a
microwave vial. The vial was then sealed and was heated in the
microwave to 120 °C at 300 W for 20 min. The reaction was then
concentrated and was purified on prep HPLC (1 f 80% MeCN/
water with 0.1% TFA over 60 min). The fractions with product
were collected, were concentrated, and were diluted with DCM.
MP-carbonate beads were added, and the suspension was stirred
for 10 min and was filtered. The beads were washed with MeOH
and CH2Cl2 three times, and the filtrate was concentrated to afford
22 (154 mg, 39%) as a yellow glass. 1H NMR (400 MHz, CDCl3,
δ): 8.50 (d, J ) 5.3 Hz, 1H), 8.15 (s, 1H), 7.72 (dd, J ) 11.6, 2.0
Hz, 1H), 7.59-7.53 (m, 2H), 7.45 (s, 1H), 7.41-7.25 (m, 6H),
6.49 (dd, J ) 5.3, 0.9 Hz, 1H), 4.28 (t, J ) 6.7 Hz, 2H), 4.23 (s,
2H), 4.04 (s, 3H), 3.75-3.70 (m, 4H), 3.55 (s, 3H), 2.58 (t, J )
7.2 Hz, 2H), 2.53-2.46 (m, 4H), 2.19-2.08 (m, 2H). MS (ES)
m/z: 611 (M + H+). Anal. Calcd for (C35H35FN4O5 ·0.2CH2Cl2):
C, H, N.
2-Benzyl-5-(3-fluoro-4-(6-methoxy-7-(3-(pyrrolidin-1-yl)pro-
poxy)quinolin-4-yloxy)-phenyl)-3-methylpyrimidin-4(3H)-
one (23). By using chloride 17 and by following the procedure
that was used to prepare 22, we obtained 23 (4%) as a white solid.
1H NMR (400 MHz, d6-DMSO, δ): 8.50 (d, J ) 8.0 Hz, 1H), 8.30
(s, 1H), 7.93 (dd, J ) 16.0, 4.0 Hz, 1H), 7.74 (d, J ) 8.0 Hz, 1H),
7.53 (s, 1H), 7.51 (t, J ) 8.0 Hz, 1H), 7.41-7.26 (m, 6H), 6.51 (d,
J ) 8.0 Hz, 1H), 4.29 (s, 2H), 4.21 (t, J ) 8.4 Hz, 2H), 3.96 (s,
3H), 3.52 (s, 3H), 2.62-2.52 (m, 2H), 2.52-2.40 (m, 4H, buried
1
a light-yellow solid. H NMR (400 MHz, d6-DMSO, δ): 8.50 (d,
J ) 5.1 Hz, 1H), 8.29 (s, 1H), 7.92 (dd, J ) 12.5, 2.0 Hz, 1H),
7.74 (d, J ) 12.0 Hz, 1H), 7.53 (s, 1H), 7.50 (t, J ) 12.0 Hz, 1H),
7.41-7.27 (m, 6H), 6.51 (d, J ) 5.3 Hz, 1H), 4.28 (s, 2H), 4.19 (t,
J ) 6.4 Hz, 2H), 3.95 (s, 3H), 3.52 (s, 3H), 2.46 (t, J ) 7.0 Hz,
2H), 2.50-2.25 (m, 8H), 2.15 (s, 3H), 1.97 (qn, J ) 10 Hz, 2H).
MS (ES) m/z: 624 (M + H+). HRMS calcd for C36H39FN5O4 (M
+ H+), 624.2986; found, 624.2962. Analytical HPLC: 98.8%. tR
) 4.91.
2-Benzyl-5-(3-fluoro-4-(7-(3-(4-hydroxy-piperidin-1-yl)propoxy)-
6-methoxyquinolin-4-yloxy)phenyl)-3-methylpyrimidin-4(3H)-
one (27). By using chloride 21, we prepared compound 27 by
following the procedure that was used to prepare 25, except NMP
was used instead of pyridine and was added after the mixture was
stirred overnight. Compound 27 was isolated in 6% yield as an
1
off-white solid as a TFA salt. H NMR (500 MHz, CD3OD, δ):
8.45 (d, J ) 5.5 Hz, 1H), 8.23 (s, 1H), 7.81 (dd, J ) 11.9, 2.1 Hz,
1H), 7.67 (s, 1H), 7.65 (d, J ) 7.1 Hz, 1H), 7.43 (t, J ) 8.4 Hz,
1H), 7.40-7.36 (m, 3H), 7.33-7.28 (m, 3H), 6.58 (d, J ) 5.2 Hz,
1H), 4.31 (s, 2H), 4.28 (t, J ) 5.9 Hz, 2H), 4.03 (s, 3H), 3.77 (br
s, 1H), 3.56 (s, 3H), 3.14-3.05 (m, 2H), 2.93-2.86 (m, 2H),
2.65-2.55 (m, 2H), 2.22 (qn, J ) 7.0 Hz, 2H), 1.99-1.93 (m,

5774 Journal of Medicinal Chemistry, 2008, Vol. 51, No. 18
D’Angelo et al.
2H), 1.73-1.65 (m, 2H). MS (ES) m/z: 625 (M + H+). Analytical
HPLC: 98.9%. tR ) 5.32.
General Procedure for the Synthesis of 32 and 33. 2-Benzyl-
5-(3-fluoro-4-hydroxy-phenyl)pyrimidin-4(3H)-one (32). We bro-
minated 2-benzyl-pyrimidin-4(3H)-one (28) by following the
procedure that was used for the bromination of 9 to afford 2-benzyl-
5-bromopyrimidin-4(3H)-one in 29% yield.
with 0.1% TFA) to afford pure 7. 1H NMR (400 MHz, CDCl3, δ):
8.52 (d, J ) 5.3 Hz, 1H), 8.16 (s, 1H), 7.73 (dd, J ) 11.7, 2.1 Hz,
1H), 7.60 (s, 1H), 7.57 (dd, J ) 9.4, 0.9 Hz, 1H), 7.45 (s, 1H),
7.42-7.25 (m, 6H), 6.51 (dd, J ) 6.8, 0.8 Hz, 1H), 4.23 (s, 2H),
4.08 (s, 3H), 4.07 (s, 3H), 3.56 (s, 3H). MS (ES) m/z: 498 (M +
H+). Anal. Calcd for (C29H24FN3O4 ·0.1CH2Cl2): C, H, N.
2-(Bromo(phenyl)methyl)-5-(4-(6,7-dimethoxyquinolin-4-yloxy)-
3-fluorophenyl)-3-methylpyrimidin-4(3H)-one (36). Compound
7 (300 mg, 0.604 mmol) was diluted with CHCl3, and NBS (0.24
g, 1.3 mmol) was added. The reaction was heated at reflux for 3 h,
and then more NBS (53 mg, 0.30 mmol) was added. After another
2 h, the reaction was cooled to room temperature, was concentrated,
and was purified via column chromatography (0 f 5% MeOH/
DCM). A second column chromatography was necessary that used
EtOAc as the eluent to afford pure 36 (113 mg, 32%) as a tan
2-Benzyl-5-bromopyrimidin-4(3H)-one (100 mg, 0.379 mmol),
3-fluoro-4-methoxyphenylboronic acid (128 mg, 0.756 mmol),
Pd(PPh3)4 (22 mg, 0.019 mmol), and Na2CO3 (1 M in water, 0.5
mL, 0.5 mmol) were suspended in DME (1.5 mL) and were heated
in the CEM microwave to100 °C at 75 W for 10 min. The reaction
was cooled to room temperature and was diluted with water and
DCM. The organic layer was collected, was dried over sodium
sulfate, was filtered through celite, and was concentrated. Purifica-
tion via silica gel chromatography (ISCO column, 12 g, 0 f 5%
MeOH/DCM) afforded 30 (86 mg, 74%) as a white solid.
Finally, we converted 30 to phenol 32 by following the
demethylation procedure (HBr and HOAc) that was used to prepare
1
solid. H NMR (400 MHz, CDCl3, δ): 8.44 (d, J ) 5.3 Hz, 1H),
8.09 (s, 1H), 7.65 (dd, J ) 11.6, 2.0 Hz, 1H), 7.50 (s, 1H),
7.51-7.43 (m, 3H), 7.41 (s, 1H), 7.38-7.28 (m, 3H), 7.25-7.18
(m, 1H), 6.43 (d, J ) 5.3 Hz, 1H), 6.13 (s, 1H), 3.97 (s, 6H), 3.55
(s, 3H). MS (ES) m/z: 576 (Br79, M + H +), 578 (Br81, M +
H+).
1
11. Compound 32 was isolated in 65% yield as a white solid. H
NMR (400 MHz, d6-DMSO, δ): 12.88 (s, 1H), 9.98 (s, 1H), 8.09
(s, 1H), 7.58 (dd, J ) 13.3, 2.3 Hz, 1H), 7.39-7.30 (m, 5H),
7.29-7.22 (m, 1H), 6.95 (t, J ) 8.8 Hz, 1H), 3.89 (s, 2H). MS
(ES) m/z: 297 (M + H+).
2-(Amino(phenyl)methyl)-5-(4-(6,7-dimethoxyquinolin-4-yloxy)-
3-fluorophenyl)-3-methylpyrimidin-4(3H)-one (37). Compound
36 (130 mg, 0.226 mmol) was dissolved in DMF (3 mL) and was
cooled to 0° C. NaN3 (18 mg, 0.28 mmol) was added, and the
reaction was stirred for 1 h. It was then concentrated, treated with
CHCl3 and DCM, washed with water, and dried over sodium sulfate.
The organic phase was decanted and concentrated and was taken
directly to the next step.
2-Benzyl-5-(3-fluoro-4-hydroxyphenyl)-6-methylpyrimidin-
4(3H)-one (33). Compound 33 was prepared from 2-benzyl-6-
methyl-pyrimidin-4(3H)-one (29) with the same three-step sequence
1
that was used to synthesize 32. H NMR (400 MHz, d6-DMSO,
δ): 12.67 (br s, 1H), 9.90 (br s, 1H), 7.39-7.31 (m, 4H), 7.28-7.23
(m, 1H), 7.03 (dd, J ) 12.6, 2.0 Hz, 1H), 6.94 (t, J ) 8.8 Hz, 1H),
6.85 (dd, J ) 8.4, 1.6 Hz, 1H), 3.83 (s, 2H), 2.07 (s, 3H). MS (ES)
m/z: 311 (M + H+).
The crude material was diluted with EtOAc and THF, and Pd-C
(10% by weight, 24 mg) was added. The reaction was then stirred
under a balloon of hydrogen for 4.5 h, was flushed with nitrogen,
and was filtered through a pad of celite. The filtrate was concen-
trated and purified via silica gel chromatography (ISCO amino-
propyl column, 40 g, 0 f 5% MeOH/DCM) to afford 37 (31 mg,
2-Benzyl-5-(4-(6,7-dimethoxyquinolin-4-yloxy)-3-fluorophe-
nyl)pyrimidin-4(3H)-one (34). Compound 32 (100 mg, 0.334
mmol), 4-chloro-6,7-dimethoxyquinoline (113 mg, 0.505 mmol),
and DMAP (41 mg, 0.336 mmol) were suspended in PhMe (2 mL)
and CHCl3 (1 mL) and were heated in the microwave to 180 °C
(with variable power) for 20 min and then for an additional 10
min. The reaction was then cooled to room temperature, was
concentrated, was treated with DCM, and was filtered. The white
solid was collected, and the filtrate was concentrated and purified
via silica gel chromatography (ISCO column, 40 g, 0 f 5% MeOH/
DCM) to afford, after combining with the solid collected earlier,
34 (86 mg, 53%) as a white solid. 1H NMR (400 MHz, CDCl3, δ):
10.77 (br s, 1H), 8.52 (d, J ) 5.3 Hz, 1H), 8.22 (s, 1H), 7.74 (dd,
J ) 11.4 Hz, 2.1 Hz, 1H), 7.59 (s, 1H), 7.60-7.55 (m, 1H), 7.45
(s, 1H), 7.43-7.30 (m, 6H), 6.51 (d, J ) 5.3 Hz, 1H), 4.09 (s,
2H), 4.08 (s, 3H), 4.07 (s, 3H). MS (ES) m/z: 484 (M + H+).
HRMS calcd for C28H23FN3O4 (M + H+), 484.1673; found,
484.1649. Analytical HPLC: 96.9%. tR ) 1.66.
1
27% yield over two steps) as a yellow oil. H NMR (400 MHz,
CDCl3, δ): 8.51 (d, J ) 5.0 Hz, 1H), 8.41 (s, 1H), 7.93 (dd, J )
12.3, 1.8 Hz, 1H), 7.76 (d, J ) 8.5 Hz, 1H), 7.54 (s, 1H), 7.51 (t,
J ) 8.8 Hz, 1H), 7.44-7.34 (m, 5H), 7.32-7.27 (m, 1H), 6.53 (d,
J ) 5.0 Hz, 1H), 5.31 (s, 1H), 3.96 (s, 6H), 3.50 (s, 3H), 2.73 (br
s, 2H). MS (ES) m/z: 513 (M + H+). Anal. Calcd for (C29H25FN4O4 ·
0.5CH2Cl2): C, H, N.
General Procedure for the Synthesis of 38-41. N-((5-(4-(6,7-
Dimethoxyquinolin-4-yl-oxy)-3-fluorophenyl)-1-methyl-6-oxo-
1,6-dihydropyrimidin-2-yl)(phenyl)methyl)-2-(dimethylamino)ac-
etamide) (38). Amine 37 (25 mg, 0.049 mmol) was diluted with
DCM and was cooled in an ice-water bath. Et3N (0.034 mL, 0.25
mmol) and 2-(dimethylamino)acetyl chloride hydrochloride salt (9
mg, 0.06 mmol) were added, and the reaction was stirred at room
temperature until TLC analysis indicated a complete reaction. More
Et3N and 2-(dimethylamino)acetyl chloride hydrochloride salt were
added as needed to afford a complete reaction. Upon completion,
the reaction was concentrated and purified via silica gel chroma-
tography (ISCO column, 12 g, 0 f 5% MeOH/DCM) to afford 38
(14 mg, 48% yield) as a tan solid. 1H NMR (400 MHz, CDCl3, δ):
8.57 (d, J ) 8.3 Hz, 1H), 8.52 (d, J ) 5.3 Hz, 1H), 8.23 (s, 1H),
7.73 (dd, J ) 11.6, 2.0 Hz, 1H), 7.59 (s, 1H), 7.60-7.55 (m, 1H),
7.46 (s, 1H), 7.43-7.35 (m, 5H), 7.32 (t, J ) 8.4 Hz, 1H), 6.51 (d,
J ) 5.3 Hz, 1H), 6.34 (d, J ) 8.3 Hz, 1H), 4.07 (s, 3H), 4.06 (s,
3H), 3.54 (s, 3H), 3.01 (s, 2H), 2.32 (s, 6H). MS (ES) m/z: 598 (M
+ H+). HRMS calcd for C33H33FN5O5 (M + H+), 598.2466; found,
2-Benzyl-5-(4-(6,7-dimethoxyquinolin-4-yl-oxy)-3-fluorophe-
nyl)-6-methylpyrimidin-4(3H)-one (35). By following the proce-
dure that was used to prepare 34, we prepared compound 35 from
phenol 33 in 24% yield as a white solid. 1H NMR (400 MHz,
CDCl3, δ): 8.49 (d, J ) 5.1 Hz, 1H), 7.60 (s, 1H), 7.45 (s, 1H),
7.42-7.26 (m, 8H), 7.19 (d, J ) 8.2 Hz, 1H), 6.53 (d, J ) 5.1 Hz,
1H), 4.07 (s, 3H), 4.06 (s, 3H), 3.96 (s, 2H), 2.34 (s, 3H). MS
(ES) m/z: 498 (M + H+). HRMS calcd for C29H25FN3O4 (M +
H+), 498.1829; found, 498.1812. Analytical HPLC: 95.2%. tR
2.36.
)
2-Benzyl-5-(4-(6,7-dimethoxyquinolin-4-yl-oxy)-3-fluorophe-
nyl)-3-methylpyrimidin-4(3H)-one (7). Compound 34 (25 mg,
0.052 mmol) was dissolved in DMF, and K2CO3 (11 mg, 0.080
mmol) and MeI (0.004 mL, 0.06 mmol) were added. The reaction
was stirred at 43 °C (oil bath temperature) for 2 h, was diluted
with DCM, and was washed with water twice and with brine once.
The organic layer was dried over sodium sulfate, was filtered, was
concentrated, and was purified on silica gel chromatography (ISCO
column, 12 g, 0 f 5% MeOH/DCM) to afford a 6:1 mixture of 7
and the undesired O-methylated isomer (11 mg, 42% total yield).
This mixture was purified via HPLC (70 f 100% MeCN/water
598.2444. Analytical HPLC: 96.9%. t ) 2.43.
R
N-((5-(4-(6,7-Dimethoxyquinolin-4-yloxy)-3-fluorophenyl)-1-
methyl-6-oxo-1,6-dihydropyrimidin-2-yl)(phenyl)methyl)-propi-
onamide (39). By using propionyl chloride, and by following the
procedure that was used to prepare 38, we obtained 39 (51%) as
1
an off-white solid. H NMR (300 MHz, CDCl3, δ): 8.52 (d, J )
5.3 Hz, 1H), 8.18 (s, 1H), 7.71 (dd, J ) 11.6 Hz, 2.0 Hz, 1H),
7.59 (s, 1H), 7.60-7.54 (m, 1H), 7.44 (s, 1H), 7.42-7.31 (m, 6H),
7.30-7.24 (m, 1H), 6.51 (dd, J ) 5.3, 0.7 Hz, 1H), 6.31 (d, J )
7.6 Hz, 1H), 4.07 (s, 3H), 4.06 (s, 3H), 3.52 (s, 3H), 2.31 (dq, J )

Potent c-Met Inhibitors
Journal of Medicinal Chemistry, 2008, Vol. 51, No. 18 5775
7.8, 1.5 Hz, 2H), 1.18 (t, J ) 7.5 Hz, 3H). MS (ES) m/z: 569 (M
+ H+). Anal. Calcd for (C32H29FN4O5 ·0.2CH2Cl2): C, H, N.
N-((5-(4-(6,7-Dimethoxyquinolin-4-yloxy)-3-fluorophenyl)-1-
methyl-6-oxo-1,6-dihydropyrimidin-2-yl)(phenyl)methyl)-3-(me-
thylthio)propanamide (40). By using 3-(methylthio)propanoyl
chloride, and by following the procedure that was used to prepare
38, we obtained 40 (47%) as an off-white solid. 1H NMR (300
MHz, CDCl3, δ): 8.53 (d, J ) 5.3 Hz, 1H), 8.18 (s, 1H), 7.72 (dd,
J ) 11.6 Hz, 2.1, 1H), 7.59 (s, 1H), 7.59-7.54 (m, 1H), 7.53-7.47
(m, 1H), 7.48 (s, 1H), 7.42-7.37 (m, 5H), 7.32 (t, J ) 8.3 Hz,
1H), 6.51 (d, J ) 5.3 Hz, 1H), 6.30 (d, J ) 7.5 Hz, 1H), 4.07 (s,
3H), 4.06 (s, 3H), 3.52 (s, 3H), 2.84-2.77 (m, 2H), 2.61-2.55
(m, 2H), 2.09 (s, 3H). MS (ES) m/z: 615 (M + H+). HRMS calcd
for C33H32FN4O5S (M + H+), 615.2077; found, 615.2067. Analyti-
cal HPLC: 96.2%. tR ) 1.87.
3-((5-(4-(6,7-Dimethoxyquinolin-4-yloxy)-3-fluorophenyl)-1-
methyl-6-oxo-1,6-dihydro-pyrimidin-2-yl)(phenyl)methyl)-1,1-
dimethyl-urea (41). By using dimethylcarbamic chloride, and by
following the procedure that was used to prepare 38, we obtained
41 as an off-white solid. 1H NMR (300 MHz, CDCl3, δ): 8.53 (d,
J ) 5.1 Hz, 1H), 8.19 (s, 1H), 7.72 (dd, J ) 11.6 Hz, 2.0, 1H),
7.59 (s, 1H), 7.60-7.55 (m, 1H), 7.45 (s, 1H), 7.42-7.36 (m, 5H),
7.31 (t, J ) 8.3 Hz, 1H), 6.51 (d, J ) 5.1 Hz, 1H), 6.26-6.22 (m,
1H), 6.19-6.14 (m, 1H), 4.08 (s, 3H), 4.06 (s, 3H), 3.54 (s, 3H),
2.96 (s, 6H). MS (ES) m/z: 584 (M + H+). Anal. Calcd for
(C32H30FN5O5 ·0.3CH2Cl2): C, H, N.
General Procedure for the Synthesis of 42, 43, and 51.
2-(4-Methylbenzyl)-5-(3-fluoro-4-(6-methoxy-7-(3-morpholino-
propoxy)-quinolin-4-yloxy)phenyl)-3-methylpyrimidin-4(3H)-
one (42). 4-Chloro-6-methoxy-7-(3-morpholinopropoxy)quinoline
(16, 116.7 mg, 0.346 mmol), 2-(4-methylbenzyl)-5-(3-fluoro-4-
hydroxyphenyl)-3-methylpyrimidin-4(3H)-one (12, 120.6 mg, 0.372
mmol), copper powder (9.8 mg, 0.15 mmol), and solid KOH (56.1
mg, 1.0 mmol) were suspended in DMF (1 mL) and pyridine (1
mL) and were heated in the CEM microwave to 110 °C at 110 W
for 18 min. The reaction was cooled to room temperature. We ran
five more reactions in the microwave by using the same reagents
in approximately the same amounts. For all six runs, the total
amounts of 16 and 12 used were 1.164 g (3.457 mmol) and 1.417
g (4.370 mmol), respectively. Once completed, all six reactions
were combined and were poured into 1 N NaOH (39 mL), which
was then diluted with DCM. The layers were separated, and the
aqueous phase was extracted repeatedly with DCM. The organic
phases were combined, were dried over sodium sulfate, were
filtered, were concentrated, and were purified on HPLC (1 f 70%
MeCN/water with 0.1% TFA over 55 -65 min). The fractions with
product were collected, were concentrated, and were repurified on
HPLC (10 f 95% MeCN/water with 0.1% TFA). The fractions
with product were collected, were concentrated, were diluted with
DCM (∼5 mL), and were treated with polymer-supported carbonate
(560 mg, MP-carbonate, Argonaut Aquatics, 2.75 mmol/g). The
suspension was stirred for 75 min and was then filtered. The filtrate
was concentrated and was dried under high vacuum to afford 42
(115.0 mg, 5%) as a rust-colored solid. 1H NMR (400 MHz, CDCl3,
δ): 8.53 (d, J ) 5.5 Hz, 1H), 8.16 (s, 1H), 7.74 (dd, J ) 9.6, 2.0
Hz, 1H), 7.60 (s, 1H), 7.60-7.52 (m, 2H), 7.32 (t, J ) 8.3 Hz,
1H), 7.21-7.13 (m, 4H), 6.54 (d, J ) 5.5 Hz, 1H), 4.30 (t, J ) 6.5
Hz, 2H), 4.19 (s, 2H), 4.06 (s, 3H), 3.83-3.78 (m, 4H), 3.56 (s,
3H), 2.80-2.60 (m, 6H), 2.36 (s, 3H), 2.25-2.17 (m, 2H). MS
(ES) m/z: 625 (M + H+). Anal. Calcd for (C36H37FN4O5 ·
0.6CH2Cl2): C, H, N.
2.42-2.37 (m, 4H), 1.98 (qn, J ) 6.0 Hz, 2H). MS (ES) m/z: 629
(M + H+). Anal. Calcd for (C35H34F2N4O5 ·0.2CH2Cl2) C, H, N:
Found, 65.90; Calcd, 65.48.
5-(3-Fluoro-4-(6-methoxy-7-(3-morpholino-propoxy)quinolin-
4-yloxy)phenyl)-2-(4-fluorophenylamino)-3-methylpyrimidin-
4(3H)-one (51). By using phenol 47, and by following the procedure
that was used to prepare 42, we obtained 51 (6%) as a tan solid.
1H NMR (400 MHz, d6-DMSO, δ): 9.06 (s, 1H), 8.49 (d, J ) 5.3
Hz, 1H), 8.09 (s, 1H), 7.87 (dd, J ) 12.8, 1.7 Hz, 1H), 7.67 (d, J
) 8.8 Hz, 1H), 7.57-7.51 (m, 3H), 7.46-7.39 (m, 2H), 7.22 (t, J
) 8.8 Hz, 2H), 6.49 (d, J ) 5.1 Hz, 1H), 4.21 (t, J ) 5.7 Hz, 2H),
3.95 (s, 3H), 3.63-3.57 (m, 4H), 3.57 (s, 3H), 2.50-2.35 (m, 6H),
2.06-1.93 (m, 2H). MS (ES) m/z: 630 (M + H+). Anal. Calcd for
(C34H33F2N5O5 ·0.4CH2Cl2): C, H, N.
5-(3-Fluoro-4-hydroxyphenyl)-3-methyl-2-(methylthio)pyri-
midin-4(3H)-one (44). Compound 10 (10.0 g, 35.8 mmol) was
dissolved in HOAc (60 mL) and 48% aqueous HBr (240 mL). The
flask was equipped with a reflux condenser and was placed in a
preheated oil bath (115-120 °C) and was stirred for 3 h. The
reaction was then cooled to room temperature and was poured into
a 2 L Erlenmeyer flask. Saturated NaHCO3 (1.3 L) was added in
portions over 1 h, and the solution was stirred overnight at room
temperature. Then, 5 N NaOH (100 mL) was added, and stirring
was continued for 20 min. The suspension was filtered, and the
solid was collected and dried under high vacuum at 60 °C to afford
1
44 (9.8 g, ∼100%) as a white solid. H NMR (400 MHz, CDCl3,
δ): 7.95 (s, 1H) 7.51 (dd, J ) 11.9, 2.0 Hz, 1H), 7.30-7.25 (m,
1H), 7.02 (t, J ) 8.8 Hz, 1H), 5.33 (br s, 1H), 3.61 (s, 3H), 2.65
(s, 3H). MS (ES) m/z: 267 (M + H+).
General Procedure for the Synthesis of 48-50. 5-(4-(6,7-
Dimethoxyquinolin-4-yloxy)-3-fluorophenyl)-3-methyl-2-(phe-
nylamino)-pyrimidin-4(3H)-one (48). Phenol 44 (508.1 mg, 1.908
mmol) was suspended in aniline (4.5 mL), and concentrated HCl
(3 drops) was added. The suspension was sealed in a microwave
vial and was heated in the CEM microwave to120 °C at 100 W for
10 min. The reaction was diluted with EtOAc (∼100 mL) and was
washed with 1 N NaOH (3 × 25 mL). The aqueous washings were
combined and were extracted with EtOAc (10 mL). This EtOAc
extraction was washed with 1 N NaOH (20 and 10 mL). Finally,
all of the aqueous extractions were combined, were washed with
Et2O (3 × 15 mL), and were treated with 1 N HCl to lower the pH
to about 8. The aqueous phase was extracted with EtOAc, and these
organic extracts were combined and were washed with water (3 ×
10 mL) and 1 N NaOH. The pH of these aqueous washings was
adjusted with to be around 6 by concentrated HCl and then 1 N
NaOH, and this aqueous phase was extracted with EtOAc and Et2O.
These organic extracts were combined, were dried over sodium
sulfate, were filtered, were concentrated, and were dried under high
vacuum to afford phenol 45 (466.1 mg, 78%).
Phenol 45 (210.3 mg, 0.6756 mmol), 4-chloro-6,7-dimethoxy-
uinoline (247.2 mg, 1.106 mmol, and DMAP (29.8 mg, 0.244
mmol) were suspended in 1,4-dioxane (4.0 mL) and were heated
in the CEM microwave to 120 °C at 300 W for 20 min. The reaction
was briefly cooled and was then reheated under the same conditions
for 15 min. The reaction was cooled to room temperature once
more, was concentrated, and was purified via HPLC (10 f 95%
MeCN/water with 0.1% TFA). The fractions with product were
collected, were concentrated, and were filtered through a plug of
silica gel with EtOAc and then with 5% MeOH/EtOAc. The filtrate
was concentrated and was again filtered through silica gel with
EtOAc. Fractions with product were collected, were concentrated,
and were dried under high vacuum to afford 48 (20.9 mg, 6%).
For analytical purposes, a 4 mg aliquot was purified on a pipet
silica gel column (50:1 f 25:1 DCM/MeOH) to afford analytically
2-(4-Fluorobenzyl)-5-(3-fluoro-4-(6-methoxy-7-(3-morpholi-
nopropoxy)quinolin-4-yloxy)phenyl)-3-methylpyrimidin-4(3H)-
one (43). By using phenol 13, and by following the procedure that
was used to prepare 42, we obtained 43 (1%) as a rust-colored
1
1
solid. H NMR (400 MHz, d6-DMSO, δ): 8.50 (d, J ) 5.3 Hz,
pure material. H NMR (400 MHz, CDCl3, δ): 8.50 (d, J ) 5.3
1H), 8.27 (s, 1H), 7.91 (dd, J ) 12.5, 2.0 Hz, 1H), 7.73 (d, J ) 8.4
Hz, 1H), 7.53 (s, 1H), 7.50 (t, J ) 8.6 Hz, 1H), 7.42 (s, 1H), 7.34
(dd, J ) 8.5, 5.8 Hz, 2H), 7.19 (t, J ) 8.9 Hz, 2H), 6.51 (d, J )
5.3 Hz, 1H), 4.27 (s, 2H), 4.21 (t, J ) 6.5 Hz, 2H), 3.95 (s, 3H),
3.59 (t, J ) 4.5 Hz, 4H), 3.54 (s, 3H), 2.50-2.44 (m, 2H),
Hz, 1H), 7.97 (s, 1H), 7.66 (dd, J ) 11.9, 2.0 Hz, 1H), 7.60 (s,
1H), 7.52-7.38 (m, 7H), 7.25-7.20 (m, 2H), 6.51 (dd, J ) 5.3,
1.0 Hz, 1H), 4.07 (s, 3H), 4.05 (s, 3H), 3.69 (s, 3H). MS (ES) m/z:
499 (M + H+). HRMS calcd for C28H24FN4O4 (M + H+),
499.1782; found, 499.1767. Analytical HPLC: 96.6%. tR ) 1.74.

5776 Journal of Medicinal Chemistry, 2008, Vol. 51, No. 18
D’Angelo et al.
5-(4-(6,7-Dimethoxyquinolin-4-yloxy)-3-fluorophenyl)-2-(2-
fluorophenylamino)-3-methylpyrimidin-4(3H)-one (49). By using
phenol 46 (prepared in the same manner as 45 above) and 4-chloro-
6,7-dimethoxyquinoline, and by following the procedure that was
used to prepare 48, we obtained 49 (1%) as an off-white solid. 1H
NMR (400 MHz, d6-DMSO, δ): 9.12 (s, 1H), 8.57 (s, 1H), 8.05 (s,
1H), 7.87 (d, J ) 12.5 Hz, 1H), 7.73-7.22 (m, 8 H), 6.61 (s, 1H),
3.97 (s, 6H), 3.58 (s, 3H). MS (ES) m/z: 517 (M + H+). HRMS
calcd for C28H23F2N4O4 (M + H+), 517.1687; found, 517.1667.
Analytical HPLC: 98.1%. tR ) 2.27.
5-(4-(6,7-Dimethoxyquinolin-4-yloxy)-3-fluorophenyl)-2-(4-
fluorophenylamino)-3-methylpyrimidin-4(3H)-one (50). By using
phenol 47 (prepared in the same manner as 45 above) and 4-chloro-
6,7-dimethoxyquinoline, and by following the procedure that was
used to prepare 48, we obtained 50 (6%) as an off-white solid. 1H
NMR (400 MHz, d6-DMSO, δ): 9.06 (s, 1H), 8.66 (s, 1H), 8.12 (s,
1H), 7.92 (d, J ) 13.1 Hz, 1H), 7.73 (d, J ) 9.8 Hz, 1H), 7.68-7.63
(m, 1H), 7.53-7.47 (m, 3H), 7.51-7.47 (m, 1H), 7.23 (t, J ) 8.9
Hz, 2H), 6.74 (m, 1H), 4.00 (s, 6H), 3.57 (s, 3H). MS (ES) m/z:
517 (M + H+). HRMS calcd for C28H23F2N4O4 (M + H+),
517.1687; found, 517.1670. Analytical HPLC: 95.1%. tR ) 2.24.
5-(4-(6,7-Dimethoxyquinolin-4-yloxy)-3-fluorophenyl)-3-meth-
yl-2-(methylthio)-pyrimidin-4(3H)-one (52). Phenol 44 (2.82 g,
10.6 mmol), 4-chloro-6,7-dimethoxyquinoline (2.10 g, 9.40 mmol),
and DMAP (110.1 mg, 0.901 mmol) were suspended in pyridine
(30 mL) and 1,4-dioxane (15 mL), and the reaction flask was heated
in an oil bath (110 °C) while the reaction was stirred under argon
overnight. The reaction was cooled to room temperature, was diluted
with water (75 mL), and was filtered. The solid was washed with
water and was dried under high vacuum to afford 52 (2.50 g, 59%).
1H NMR (400 MHz, d6-DMSO, δ): 8.50 (d, J ) 5.1 Hz, 1H), 8.29
(s, 1H), 7.90 (dd, J ) 12.4, 1.7 Hz, 1H), 7.72 (d, J ) 8.8 Hz, 1H),
7.54 (s, 1H), 7.50 (t, J ) 8.6 Hz, 1H), 7.42 (s, 1H), 6.52 (d, J )
5.3 Hz, 1H), 3.95 (s, 6H), 3.52 (s, 3H), 2.62 (s, 3H). MS (ES) m/z:
454 (M + H+).
through a plug of silica gel (EtOAc, 2:1 EtOAc/MeOH f 3:2
MeOH/EtOAc). The filtrate was concentrated and was purified on
HPLC (10 f 95% MeCN/water with 0.1% TFA). The fractions
with product were collected, were concentrated, and were purified
two times on a silica gel plug (EtOAc f 1% MeOH/EtOAc the
first time, EtOAc the second time) to afford 55 (14.4 mg) as a light-
yellow solid. 1H NMR (400 MHz, d6-DMSO, δ): 9.14 (s, 1H), 8.59
(d, J ) 5.5 Hz, 1H), 8.17 (s, 1H), 7.91 (d, J ) 13.6 Hz, 1H), 7.72
(d, J ) 8.5 Hz, 1H), 7.60 (s, 1H), 7.60-7.53 (m, 1H), 7.51-7.38
(m, 4H), 7.00-6.94 (m, 1H), 6.63 (d, J ) 5.0 Hz, 1H), 3.96 (s,
6H), 3.59 (s, 3H). MS (ES) m/z: 517 (M + H+). HRMS calcd for
C28H23F2N2O4 (M + H+), 517.1687; found, 517.1672. Analytical
HPLC: 95.0%. tR ) 6.37.
5-(4-(6,7-Dimethoxyquinolin-4-yloxy)-3-fluorophenyl)-3-meth-
yl-2-(4-(trifluoro-methyl)phenylamino)pyrimidin-4(3H)-one (56).
By using 5 mL of the same solution of crude chloride 54, and by
following the procedure that was used to prepare 55, we obtained
56 (12.8 mg) as a light-yellow solid. 1H NMR (400 MHz,
d6-DMSO, δ): 9.30 (s, 1H), 8.50 (d, J ) 5.5 Hz, 1H), 8.15 (s, 1H),
7.93-7.82 (m, 3H), 7.75-7.68 (m, 3H), 7.54 (s, 1H), 7.46 (t, J )
8.5 Hz, 1H), 7.42 (s, 1H), 6.52 (d, J ) 5.0 Hz, 1H), 3.96 (s, 6H),
3.61 (s, 3H). MS (ES) m/z: 567 (M + H+). HRMS calcd for
C29H23F4N4O4 (M + H+), 567.1655; found, 567.1638. Analytical
HPLC: 95.5%. tR ) 6.96.
5-(Benzyloxy)-2-bromopyridine (57). A suspension of sodium
hydride (3.808 g, Aldrich 60%, 95.20 mmol) and DMF (25 mL)
was cooled in an ice-water bath under nitrogen, and 2-bromo-5-
hydroxypyridine (14.28 g, 82.07 mmol) was added via syringe as
a solution in DMF (120 mL) over 35 min. The reaction was warmed
to room temperature, was stirred under nitrogen for 40 min, and
was then cooled again in an ice-water bath. Benzyl bromide (12.0
mL, 98 mmol) was added via syringe, and the reaction was warmed
to room temperature and was stirred for 90 min. It was then poured
into 2.5% aqueous HCl (400 mL), and the pH of the aqueous layer
was raised to 14 with 5 N NaOH and was then lowered to 12 with
concentrated HCl, which caused precipitation. The solution was
decanted, and the decanted liquid was extracted with EtOAc (3 ×
300 mL). Organic extracts were combined, were dried over sodium
sulfate, were filtered, and were concentrated. The concentrate and
the precipitate were combined, were diluted with EtOAc (∼400
mL), and were washed with water (3 × 150 mL). The organic phase
was dried over sodium sulfate, was filtered, was concentrated, and
was filtered through a 2in silica gel with EtOAc. The filtrate was
concentrated and was dried under high vacuum to afford 57 (22.9
g). 1H NMR (400 MHz, CDCl3, δ): 8.14 (d, J ) 3.1 Hz, 1H),
7,43-7.35 (m, 6H), 7.16 (dd, J ) 8.6, 3.1 Hz, 1H), 5.10 (s, 2H).
MS (ES) m/z: 264 (Br79, M + H+), 266 (Br81, M + H+).
2-(5-(Benzyloxy)pyridin-2-yl)acetic Acid (58). 57 (22.9 g, 86.7
mmol) and Pd(PPh3)4 (11.3 g, 9.78 mmol) were dissolved in THF
(100 mL). Argon was bubbled through for 5 min, and then 2-tert-
butoxy-2-oxoethylzinc chloride (199 mL, 0.5 M in Et2O, 99.5
mmol) was added via syringe. The flask was equipped with a reflux
condensor and was placed in a preheated oil bath (60 °C) and was
stirred under argon. After 4 h, more Pd(PPh3)4 (0.62 g, 0.54 mmol)
was added. Stirring was continued at reflux for 1 h, and then the
reaction was cooled to room temperature and was quenched with
250 mL of a 1:1 solution of saturated ammonium chloride and
saturated EDTA (disodium salt). The layers were separated, and
the aqueous phase was extracted with EtOAc (200 mL). The organic
extracts were combined, were dried over sodium sulfate, were
filtered, and were concentrated. After the mixture sat at room
temperature overnight, a precipitate formed, so the suspension was
refiltered, and the filtrate was concentrated and was filtered through
a 2in silica gel with 5:1 f 2:1 hexanes/EtOAc f EtOAc.
The filtrate was concentrated, was dissolved in DCM (250 mL),
and was cooled to 0 °C in an ice-water bath under argon. TFA (30
mL, 404 mmol) was added via syringe, and the reaction was allowed
to warm to room temperature while being stirring overnight.
The next morning, an additional 30 mL of TFA was added, and
stirring was continued at room temperature. After 5 h, the reaction
was concentrated, was poured into 10% aqueous sodium carbonate
5-(4-(6,7-Dimethoxyquinolin-4-yloxy)-3-fluorophenyl)-2-hy-
droxy-3-methylpyrimidin-4(3H)-one (53). Compound 52 (8.90 g,
19.6 mmol) was dissolved in a solution of MeCN (288 mL) and
TFA (32 mL), which was then cooled to -5 °C in a dilute dry-
ice/acetone bath. Urea hydrogen peroxide (7.37 g, 78.4 mmol) was
added, and the reaction was stirred for 5 min. TFAA (10.90 mL,
78.40 mmol) was added dropwise via a dropping funnel while the
temperature was maintained at -5° C. The reaction was stirred at
this temperature for 30 min and was then allowed to warm up to
room temperature, where it was stirred for 3 h. The reaction was
then diluted with DCM and H2O, and the layers were separated.
The aqueous phase was extracted with DCM, and the organic phases
were combined, were dried over sodium sulfate, were filtered, were
concentrated, and were dried in vacuo at 100 °C over the weekend
1
to afford 53 (10.00 g, 95% yield) as a beige solid. H NMR (300
MHz, CDCl3, δ): 10.50 (d, J ) 5.4 Hz, 1H), 8.70 (d, J ) 6.6 Hz,
1H), 7.86 (s, 1H), 7.69 (s, 1H), 7.69-7.55 (m, 2H), 7.49 (d, J )
8.5 Hz, 1H), 7.36 (t, J ) 8.3 Hz, 1H), 6.80 (d, J ) 6.1 Hz, 1H),
4.15 (s, 3H), 4.13 (s, 3H), 3.42 (s, 3H). MS (ES) m/z: 424 (M +
H+).
General Procedure for the Synthesis of 55 and 56. 5-(4-(6,7-
Dimethoxyquinolin-4-yloxy)-3-fluorophenyl)-2-(3-fluorophenyl-
amino)-3-methylpyrimidin-4(3H)-one (55). Compound 53 (∼240
mg, 0.57 mmol) was dissolved in POCl3 (16 mL) and N,N-
dimethylaniline (1.6 mL). The reaction was heated to 125 °C for
8.5 h and was then cooled to room temperature and was stirred
overnight. It was then concentrated and diluted with DCM (∼125
mL). The organic phase was washed with saturated sodium
bicarbonate (25 and 17 mL), was dried over sodium sulfate, was
filtered, and was concentrated. Crude chloride 54 was dissolved in
1,4-dioxane (15 mL) and was used for the next step.
This solution (5 mL) was put in a microwave vial, and
3-fluoroaniline (0.2 mL, 2 mmol) and concentrated HCl (1 drop)
were added. The vial was sealed and was heated in the CEM
microwave to 60 °C at 60 W for 5 min. The reaction was then
cooled to room temperature, was concentrated, and was filtered

Potent c-Met Inhibitors
Journal of Medicinal Chemistry, 2008, Vol. 51, No. 18 5777
(200 mL), and was diluted with DCM (150 mL). More 10% aqueous
sodium carbonate (100 mL) was added, and the layers were
separated. The aqueous layer was washed with DCM (2 × 150
mL), and the organic extracts were then extracted with 10% aqueous
sodium carbonate (100 mL) and 1 N NaOH (50 mL). All aqueous
phases and extractions were combined, and the pH was lowered to
about 8 by concentrated HCl, which caused precipitation. This
suspension was filtered, and the pH of the filtrate was lowered to
about 4 by concentrated HCl, which caused more precipitation. This
suspension was also filtered, and the solid was allowed to dry in
the air for ∼3 days and was then dried under high vacuum at 60
°C to afford 58 (11.323 g, 57% over 3 steps). 1H NMR (400 MHz,
d6-DMSO, δ): 12.50-12.21 (br s, 1H), 8.24 (d, J ) 3.0 Hz, 1H),
7.48-7.30 (m, 6H), 7.27 (d, J ) 8.5 Hz, 1H), 5.17 (s, 2H), 3.66
(s, 2H). MS (ES) m/z: 244 (M + H+).
Phenol 61 (574 mg, 1.84 mmol), chloride 16 (458.9 mg, 1.36
mmol), and DMAP (20.9 mg, 0.18 mmol) were dissolved in
pyridine (4.6 mL) and 1,4-dioxane (2.3 mL) in a 50 mL round-
bottomed flask. The flask was fit with a reflux condenser, was placed
in a preheated oil bath (130-135 °C), and was stirred under nitrogen
for 5 h.
The reaction was cooled to room temperature, was poured into
1 N NaOH (17 mL), and was extracted with DCM (4 × 30 mL, 2
× 50 mL). The organic extracts were combined, were dried over
magnesium sulfate, were filtered, were concentrated, and were
filtered through silica gel (2 in, 10:1 f 5:1 DCM/MeOH f 5:1
DCM/2 N ammonia in MeOH). The filtrate was concentrated and
was purified on silica gel (20:1 f 10:1 DCM/2 N ammonia in
MeOH). It was repurified on silica gel (10:1 DCM/2 N ammonia
in MeOH) to afford 62 (106.8 mg, 13%) as a light-orange solid.
1H NMR (400 MHz, CDCl3, δ): 8.75 (s, 1H), 8.54-8.51 (m, 2H),
8.47 (d, J ) 8.8 Hz, 1H), 7.55 (s, 1H), 7.55-7.51 (m, 1H),
7.50-7.45 (m, 3H), 7.13 (t, J ) 8.6 Hz, 2H), 6.54 (d, J ) 5.3 Hz,
1H), 6.46 (s, 1H), 4.29 (t, J ) 6.7 Hz, 2H), 4.04 (s, 3H), 3.75-3.72
(m, 4H), 3.71 (s, 3H), 2.59 (t, J ) 7.1 Hz, 2H), 2.53-2.47 (m,
4H), 2.15 (qn, J ) 6.8 Hz, 2H). MS (ES) m/z: 613 (M + H+).
Anal. Calcd for (C33H33FN6O5 ·0.4CH2Cl2): C, H, N.
c-Met and KDR Enzyme Assays. Ki values for specific
compounds were derived from IC50 measurements versus the c-Met
and KDR kinases that were determined by the use of homogeneous
time-resolved fluorescence (HTRF) assays, as previously de-
scribed.44 We tested molecules in a 10-point serial dilution by using
an ATP concentration of two-thirds the Km value that was
determined experimentally and was calculated by the use of the
Eadie-Hofstee and Lineweaver-Burke methods.
Cell-Based Assays. According to ref 27, PC3 and CT26 cells
were obtained from the American Type Culture Collection (ATCC,
Rockville, MD). Cells were grown as monolayers by the use of
standard cell culture conditions. IC50 measurements of compound
activities on HGF-mediated c-Met autophosphorylation were de-
termined in serum-starved PC3 (human) or CT26 (mouse) cells by
the use of a quantitative electrochemiluminescent immunoassay.
Cells were plated at a density of 20 000 cells/well in 96-well plates.
After plating (24 h), cells were starved in media that contained
0.1% BSA for 18 to 20 h. Cells were then treated with a 10-point
serial dilution of each tested compound for 1 h at 37 °C, followed
by stimulation with optimal concentrations of recombinant human
HGF for 10 min at 37 °C. Cells were washed once with PBS and
were lysed (1% Triton X-100, 50 mM Tris pH 8.0, 100 mM NaCl,
300 µM Na3OV4 and protease inhibitors). Cell lysates were
incubated with a biotin-labeled goat-anti-c-Met antibody (BAF358
for human and c-Met and BAF527 for mouse, R&D Systems,
Minneapolis, MN) for capture, followed by a mouse antiphospho-
tyrosine antibody 4G10 (Upstate, Charlottesville, VA) and a BV-
tag-labeled antimouse IgG (BioVeris, Gaithersburg, MD) as the
detection antibody. Levels of c-Met phosphorylation were then
measured on a BioVeris M-series instrument. The IC50 values are
calculated by the use of the Xlfit4-parameter equation.
Pharmacodynamic Assay. According to ref 27, the effect of
22, 51, and 62 on HGF-mediated c-Met phosphorylation in vivo
was evaluated in the liver of female BALB/c mice. Compounds
were administered by either PO or IP at 10, 30, or 100 mg/kg.
After a single dose (2 h), 12 µg human HGF was injected iv to
phosphorylate c-Met in the liver. After HGF injection (5 min), the
livers were harvested, and levels of phosphorylated c-Met were
determined by a quantitative electrochemiluminescent assay. c-Met
phosphorylation that was measured in livers from mice that were
injected with BSA and were treated with vehicle served as a
negative control and indicated the background level. Livers from
mice that were injected with HGF and were treated with vehicle
established the maximal level of c-Met phosphorylation in the liver.
Statistical significance was evaluated by analysis of variance
(ANOVA), followed by the Bonferroni/Dunn post hoc test by the
use of StatView software v5.0.1. Data represent the mean (n ) 3)
( standard deviation.
5-(5-(Benzyloxy)pyridin-2-yl)-3-methyl-2-(methylthio)pyrimi-
din-4(3H)-one (60). Acid 58 (11.323 g, 46.55 mmol) was sus-
pended in DCM (200 mL), and DMF (0.25 mL) was added. Then,
(COCl)2 (4.5 mL, 52 mmol) was added dropwise via syringe over
25 min, which caused vigorous gas evolution. The reaction was
stirred at room temperature for about 10 min, and salt 59 (15.71 g,
54.74 mmol) was added. The suspension was cooled to 0 °C,
triethylamine (23.0 mL, 165 mmol) was added via syringe, and
DCM (3.5 mL) was added to rinse the sides of the flask. The
solution was allowed to warm to room temperature and was stirred
for 41 h. The reaction was then quenched with water (175 mL),
and the layers were separated. The aqueous phase was extracted
with DCM (2 × 150 mL), and the organic extracts and phases were
combined, were dried over MgSO4, were filtered, were concentrated,
and were filtered through silica gel (∼2 in) with DCM f 100:1 f
10:1 DCM/MeOH. The fractions with product were collected, were
concentrated, and were filtered again through silica gel with DCM
f 100:1 f 10:1 DCM/MeOH. We repeated this process one last
time by using an eluent system of DCM f 100:1 f 50:1 DCM/
MeoH. Fractions with product were collected and concentrated, and
the solid was washed with hexanes, Et2O, and EtOAc and was
filtered. The solid was collected and was set aside as batch no. 1.
The filtrate was collected, concentrated, and refiltered, and the solid
was washed with DCM. This filtrate was purified on silica gel (∼2
in, DCM f 50:1 f 10:1 f 5:1 DCM/MeOH), and the fractions
with product were combined with the solid that was set aside earlier
(batch no. 1), were concentrated, and were dried under high vacuum
to afford 60 (5.21 g, 69% purity, 23% yield). For characterization
purposes, a small amount of 60 (prepared separately) was washed
1
with MeOH and acetone and was dried in vacuo. H NMR (400
MHz, CDCl3, δ): 8.69 (s, 1H), 8.41 (d, J ) 2.8 Hz, 1H), 8.32 (d,
J ) 8.9 Hz, 1H), 7.48-7.28 (m, 6H), 5.15 (s, 2H), 3.62 (s, 3H),
2.64 (s, 3H). MS (ES) m/z: 340 (M + H+).
2-(4-Fluorophenylamino)-5-(5-(6-methoxy-7-(3-morpholino-
propoxy)quinolin-4-yloxy)-pyridin-2-yl)-3-methylpyrimidin-
4(3H)-one (62). A 100 mL round-bottomed flask was charged with
60 (1.05 g, 3.09 mmol) and 1,4-dioxane (25 mL). Then, 4-fluo-
roaniline (1.5 mL, 16 mmol) and concentrated HCl (0.04 mL, 1
mmol) were added, and the flask was fit with a reflux condenser,
was put in a preheated oil bath (120-125 °C), and was stirred under
nitrogen. After 1 day, 1.5 mL of 4-fluoroaniline was added, and
stirring was continued at reflux for 1 week total. The reaction was
then cooled to room temperature, was concentrated, and was filtered
through 2 in of silica gel with DCM f 20:1 DCM/MeOH. Fractions
with product were collected, were concentrated, and were taken to
the next step.
The material was diluted with DCM (20 mL) and BBr3 (4.0 mL,
1.0 M in DCM, 4.0 mmol) was added via syringe, which caused
precipitation to occur. The flask was placed in a water bath, was
stirred under argon for 45 min, and was then quenched with
saturated NaHCO3 (40 mL). The aqueous phase was extracted with
10:1 DCM/MeOH (4 × 100 mL, 50 mL) and 4:1 DCM/MeOH (2
× 150 mL, 50 mL, 150 mL), and the organic extracts were
combined, were dried over sodium sulfate and magnesium sulfate,
were filtered, and were concentrated to afford phenol 61 (1.157 g,
53% purity, 63% yield over 2 steps).

5778 Journal of Medicinal Chemistry, 2008, Vol. 51, No. 18
D’Angelo et al.
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HGF/NK4 is a Specific Antagonist for Pleiotrophic Actions of
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Crystallography. Crystals of c-Met were grown as previously
described.27 Compounds were dissolved in DMSO to a final
concentration of 20 mM and were then mixed with c-Met protein
to a final DMSO concentration of 4% prior to crystallization.
Crystals were grown from 12% PEG 6K, 1.0 M LiCl2, and 0.1 M
sodium citrate, pH 5.0. Large crystals that were suitable for data
collection were obtained by microseeding. Data were collected on
a FRE that was equipped with an RaxisII++ and were scaled by
the use of the Denzo/Scalepack programs. We solved the structures
by molecular replacement by using the published c-Met structure
1R1W as a search model and the program AMORE. The structures
were built and refined by the use of COOT and REFMAC. All
Figures were prepared by the use of PyMOL.
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Acknowledgment. We thank Jean-Christophe Harmange,
Ron Hermenau, and Mark Norman for their assistance in
preparing this manuscript. We also thank Howie Yu for his
assistance in retrieving and compiling analytical data.
Supporting Information Available: Elemental analyses and
HPLC methods for key compounds and X-ray data for 7 and 50.
This material is available free of charge via the Internet at http://
pubs.acs.org.
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