Substituted azoloquinolines and -quinazolines as new potent farnesyl protein transferase inhibitors

Article abstract of DOI:10.1016/j.bmcl.2003.08.080

A series of (4-chlorophenyl)-α-(1-methyl-1H-imidazol-5-yl) azoloquinolines and -quinazolines was prepared. These compounds displayed potent Farnesyl Protein Transferase inhibitory activity and tetrazolo[1,5-a] quinazolines are promising agents for oral in vivo inhibition.

Full text of DOI:10.1016/j.bmcl.2003.08.080

Bioorganic & Medicinal Chemistry Letters 13 (2003) 4365–4369
Substituted Azoloquinolines and -quinazolines as New Potent
Farnesyl Protein Transferase Inhibitors
Patrick Angibaud,a,* Xavier Bourdrez,a David W. End,b Eddy Freyne,c Michel Janicot,b
Patricia Lezouret,a Yannick Ligny,a Geert Mannens,d Siegrid Damsch,e
Laurence Mevellec,a Christophe Meyer,a Philippe Muller,a Isabelle Pilatte,a
Virginie Poncelet,a Bruno Roux,a Gerda Smets,b,y Jacky Van Dun,c
Pieter Van Remoortere,e Marc Veneta,{ and Walter Wouterse
aMedicinal Chemistry Department Johnson & Johnson Pharmaceutical Research & Development (J&JPRD),
Campus de Maigremont BP615, 27106 Val de Reuil, France
bOncology Drug Discovery, J&JPRD L.L.C. Welsh and McKean Roads, Spring-House, PA 19477-0776, USA
cOncology Drug Discovery, J&JPRD, Turnhoutseweg 30, B-2340, Belgium
dPreclinical Pharmacokinetics, J&JPRD, Turnhoutseweg 30, B-2340, Belgium
eDrug Evaluation, J&JPRD, Turnhoutseweg 30, B-2340, Belgium
Received 14 May 2003; revised 20 August 2003; accepted 25 August 2003
Abstract—A series of (4-chlorophenyl)-a-(1-methyl-1H-imidazol-5-yl)azoloquinolines and -quinazolines was prepared. These com-
pounds displayed potent Farnesyl Protein Transferase inhibitory activity and tetrazolo[1,5-a]quinazolines are promising agents for
oral in vivo inhibition.
# 2003 Elsevier Ltd. All rights reserved.
The discovery of mutated forms of the Ras protein in
approximately 30% of human cancers resulted in a
growing interest in Farnesyl Protein Transferase (FPT)
as a target for novel anti-cancer agents.1,2 FPT not only
plays a key role in enabling the Ras protein to acquire
full biological activity as a signal transducer,3ꢀ11 but its
substrates also include several other proteins which are
critical intermediates of cell signaling and cytoskeleton
organization.12ꢀ22 Thus the hypothesis that inhibition of
FPT may be beneficial in the treatment of certain can-
cers is currently being clinically tested with some drug
candidates undergoing phase II or phase III
trials.16,18,20,22
the treatment of hematological and solid tumors.23ꢀ27 In
an attempt to prevent some in vivo metabolism occur-
ring at the quinolinone nitrogen, we envisioned the
synthesis of analogues in which this nitrogen would be
incorporated into an heterocycle. As the quinazolinone
analogue of 1 has demonstrated potent in vitro enzy-
matic inhibition,28 we decided to implement the above
modifications not only in the quinoline but also in the
quinazoline series.
Herein, we describe the synthesis and inhibitory profile
of a series of (4-chlorophenyl)-a-(1-methyl-1H-imida-
zol-5-yl) azoloquinolines or quinazolines (Fig. 1),29
TM
comparing their potency with ZARNESTRA .
TM
R115777 1 (ZARNESTRA ) is a 4-phenylquinolinone
that is currently undergoing Phase II clinical trials for
[4-Amino-3-(3-chlorobenzoyl)phenyl]-(4-chlorophenyl)
methanone 228 was reacted with acetic anhydride to give
amide 3 which was cyclized into quinolinone 4 using t-
BuOK as a base (Scheme 1). Then, refluxing 4 in phos-
phorus oxychloride provided the 2-chloroquinoline 5. In
initial attempts we sought to build the azoloquinoline
heterocycle prior to the introduction of the N-methyli-
midazolyl moiety as depicted below. Therefore, 5 was
*Corresponding author. Tel.: +33-2-3261-7457; fax: +33-2-3261-
7298; e-mail: pangibau@prdfr.jnj.com
yCurrent address: Centocor, Medical Affairs Einsteinweg 92, 2333 CD
Leiden, The Netherlands.
{Current address: SERIPHARM, rue Democrite 72000 Le Mans,
France.
0960-894X/$ - see front matter # 2003 Elsevier Ltd. All rights reserved.
doi:10.1016/j.bmcl.2003.08.080

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P. Angibaud et al. / Bioorg. Med. Chem. Lett. 13 (2003) 4365–4369
condensed with either 2,2-dimethoxyethanamine or
hydrazinecarboxaldehyde to cyclize into respectively
imidazo[1,2-a]quinoline 6 or [1,2,4]triazolo[4,3-a]quino-
line 7 in acidic media. By action of n-butyllithium 1-
methylimidazole was first deprotonated at C-2 and the
resulting carbanion silylated. In the same pot, further
deprotonation at C-5 by n-butyllithium and condensa-
tion onto ketones 6 and 7 provided 8 and 9, respectively.
The hydroxyl function was then converted into the cor-
responding chlorine by reaction with thionyl chloride
which was substituted by ammonia to provide 12 and
13, respectively.
Condensation of 5-lithio-2-triethylsilyl-1-methylimid-
azole onto ketone 7 gave only a low yield. This may
have resulted from the poor solubility of 7. Therefore,
we attempted to introduce this moiety sooner in the
synthesis, namely on ketone 5 (Scheme 2). This was
achieved with a better yield (71%) and also provided us
with a common intermediate 14 for subsequent intro-
duction of the triazole (16, 17) and tetrazole (22) rings.
To access the [1,2,3]triazolo[1,5-a]quinoline 30, ortho-
aminobenzophenone 2528 was first reacted with 2-pro-
panone in acidic media to provide the 2-methylquino-
line 26 (Scheme 3). Oxidation of the methyl group with
SeO2 gave aldehyde 27 which was condensed with (para-
tolylsulfonyl)hydrazine and cyclized by heating into 28.
The hydroxyl group was then converted into the amino
moiety in two steps to give 30.
Figure 1. Structure of R115777 1 and the tricyclic analogues envi-
sioned.
The strategy depicted in Scheme 2 was applied to synth-
esis of azoloquinazolines using 2-chloroquinazoline 33 as
central intermediate (Scheme 4). 33 was prepared in two
Scheme 2. Reagents and conditions: (a) (1) 1-methylimidazole,
ClSiEt3, n-BuLi, THF, ꢀ70 ꢁC; (2) n-BuLi, ꢀ70 ꢁC, 71%; (b) H2NNH2
50% in water, dioxane, 70 ꢁC, 76%; (c) 1,1,1-triethoxyethane, n-
BuOH, 100 ꢁC, 53%; (d) triethoxymethylbenzene, n-BuOH, 100 ꢁC,
72%; (e) SOCl2, rt, R=Ph or SOCl2, toluene, R=CH3 ; (f) NH4OH,
THF, rt, 16% R=Ph; (g) NH3/i-PrOH, toluene, 0 ꢁC, 20% R=CH3;
(h) NaN3, DMF, 90 ꢁC, 41%; (i) SOCl2, 40 ꢁC; (j) NH3/i-PrOH, THF,
5 ꢁC, 39%.
Scheme 1. Reagents and conditions: (a) Ac2O, toluene, 110 ꢁC; (b) t-
BuOK, DME, rt, 86%; (c) POCl3, 80 ꢁC; (d) H2NCH2CH(OCH3)2,
120 ꢁC; (e) AcOH, xylene, 140 ꢁC, 56%; (f) hydrazinecarboxaldehyde,
n-BuOH, 120 ꢁC, then HCl 3 N, THF, 60 ꢁC, 34%; (g) (1) 1-methyli-
midazole, ClSiEt3, n-BuLi, THF, ꢀ70 ꢁC; (2) n-BuLi, ꢀ70 ꢁC, 48% 8,
9% 9; (h) SOCl2, 40 ꢁC; (i) (1) NH4OH, THF, rt, 10% 12 or (2) NH3/
i-PrOH, 5 ꢁC, 20% 13.

P. Angibaud et al. / Bioorg. Med. Chem. Lett. 13 (2003) 4365–4369
4367
Scheme 3. Reagents and conditions: (a) 2-propanone, H2SO4, AcOH,
100 ꢁC, 60%; (b) SeO2, dioxane, H2O, 100 ꢁC; (c) (para-tolylsulfonyl)
hydrazine, MeOH, 60 ꢁC, 21%; (d) SOCl2, rt; (e) NH3/i-PrOH, THF,
0 ꢁC, 13%.
Scheme 4. Reagents and conditions: (a) POCl3, 80 ꢁC; (b) (1) 1-
methylimidazole, ClSiEt3, n-BuLi, THF, ꢀ70 ꢁC; (2) n-BuLi, ꢀ70 ꢁC,
61%; (c) H2NCH2CH(OCH3)2, 120 ꢁC; (d) HCl (concd), toluene,
110 ꢁC, 6.5%; (e) hydrazinecarboxaldehyde, 80 ꢁC, 14%; (f) NaN3,
DMA, 50 ꢁC, 75%.
steps by chlorination of quinazolinone 3128 to provide
32 and then introduction of the N-methylimidazol-5-yl
moiety as in Scheme 2 with still a good yield. Imidazole
35, triazoles 36, 39 and tetrazole 37 were obtained by
following the experimental procedures depicted in
Schemes 1 and 2.
tion of the isolated FPT enzyme compared to R115777
but were 16–50 times less potent in the cellular assay.
[1,2,4]Triazoloquinoline 13 or quinazoline 41 were not
sufficiently active either in the isolated enzyme assay
(13) or in the cellular assay (41) to be further studied
(Table 2). Permuting a nitrogen and a carbon atom to
get [1,2,3]triazoloquinoline 30 did not improve its
potency.
The hydroxy substituent was also converted in two steps
into the amino (Scheme 5).
These compounds were evaluated for inhibition of FPT
in vitro and compared to 1. The structure activity rela-
tionships are presented in Tables 1–3 (Figs 2–4).
Interestingly adding a methyl substituent on the triazole
ring provided a compound with promising inhibitory
profile (20) whereas a phenyl group (21) was not better
than the hydrogen analogue 13.
Imidazoloquinoline 12 or imidazoloquinazoline 39
showed slight decreases in in vitro potency for inhibi-
We moved to tetrazoloquinoline 24 (Table 3), a com-
pound which still showed excellent enzymatic inhibition
and maintained activity in the cellular assay. It also
showed a moderate enzymatic inhibition of the enzyme
Figure 2.
Table 1. Comparison of FPT inhibition for imidazoloquinolines,
-quinazolines and R115777
Compd
X
FPT (enz) IC50, nMa
Cell proliferation IC50, nMb
1
12
39
—
C
N
0.9
7
5
1.7
28
88
aThe concentration required for a 50% reduction of the FPT-catalyzed
incorporation of [3H]-farnesylpyrophosphate into
laminB peptide.
bSee ref 28.
a biotinylated
Scheme 5. Reagents and conditions: (a) SOCl2; (b) NH3/i-PrOH, tol-
uene, 5 ꢁC, 16%, 41; (c) NH3/i-PrOH, 5 ꢁC, 22%, 39; (d) sulfonylurea,
160 ꢁC, 26%, 43.

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P. Angibaud et al. / Bioorg. Med. Chem. Lett. 13 (2003) 4365–4369
Table 4. Comparison of in vivo results for compounds 1, 20, 24b
and 43a
Compd
In vivoa % inhibition
Metabolismb
(%)
1
20
24b
43a
37%
66%
nt
nt
80%
Not significant
Not significant
97%
Figure 3.
nt, not tested.
Table 2. Comparison of FPT inhibition for triazoloquinolines,
-quinazolines and R115777
aIn vivo screening at 25 mg/kg in mice injected with T24 NIH 3T3
cells, percentage of tumor weight inhibition.28 Compounds were
administered orally once daily starting 2 days after tumor inoculation
and tumor growth inhibition was measured 17 days after administra-
tion.
Compd X4 X3 X1
R
FPT (enz)
IC50, nMa
Cell proliferation
IC50, nMb
bPercentage of parent drug remaining after 120 min incubation with
human liver microsomes.28
1
—
C
N
C
C
C
—
N
N
N
N
C
—
C
C
C
C
N
—
H
H
CH3
0.9
65% inh. @ 0.1 mM
1.7
nt
186
17.5
304
nt
13
41
20
21
30
3
1.5
Ph 60% inh. @ 0.1 mM
68% inh. @ 0.1 mM
—
Interestingly, the corresponding quinazoline 43 showed
a slightly better in vitro FTI potency but was less active
on GGPTase I inhibition. Again, one enantiomer 43a
proved to be more potent than the other one.
nt, not tested.
aThe concentration required for a 50% reduction of the FPT-cata-
lyzed incorporation of [3H]-farnesylpyrophosphate into a biotinylated
laminB peptide.
bSee ref 28.
20, 24b and 43a were in the same range of activity than
R115777. This prompted us to perform preliminary in
vivo experiments on these three compounds (Table 4).
The compounds 20 and 24b did not show any significant
inhibition of tumor growth when given orally at a dose
of 25 mg/kg
a day. However 43a demonstrated
improved in vivo antitumoral activity in murine xeno-
grafts and was also slightly more stable to metabolism
by human microsomes than was R115777. It also
showed selectivity for FPT over GGPTase I. Our atten-
tion is now focused on further evaluation of this com-
pound.
Figure 4.
Table 3. Comparison of FPT inhibition for tetrazoloquinolines,
-quinazolines and R115777
Compd X
FPT (enz)
IC50, nMa
Cell proliferation
IC50, nMb
GGPT
IC50, nMc
We have examined a number of azoloquinolines and
-quinazolines for inhibition of FPT in vitro and we have
identified compounds that are in the same range of
potency as R115777. Moreover, the tetrazolo[1,5-a]qui-
nazoline template offers a promising avenue towards
potent FTIs with improved in vivo potency.
1
24
—
C
0.9
3.5
2.5
1.7
55
12
>0.5 mM
20
10
10,000
176
461
43
N
24ad
24be
43af
43bg
C 36% inh. @ 0.1 mM
55% inh. @ 10 mM
C
N
N
1.7
0.6
22
81
>1000
nt
108
Acknowledgements
nt, not tested.
aThe concentration required for a 50% reduction of the FPT-catalyzed
incorporation of [3H]-farnesylpyrophosphate into
laminB peptide.
bSee ref 28.
a biotinylated
The authors are grateful to G. Goussot and J. M.
Argoullon for chromatographical and analytical sup-
port.
cThe concentration required for a 50% reduction of the Geranylger-
anylprotein transferase-I (GGPTase-I) catalyzed incorporation of [3H]-
geranylgeranylpyrophosphate into a biotinYRASNRSCAILpeptide.
dee>99%.30
eee=94%.30
fee>99%.31
gee=92%.31
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30. 24 (4 g) was separated into its enantiomers by column
chromatography over Chiralcel OD1 (eluent: EtOH 100%).
Two pure fractions were collected and the solvent was evapo-
rated. Fraction 1 was converted into the ethanedioic salt (1:1)
and crystallized from ethanol. The precipitate was filtered off
and dried, yielding 1.59 g (34%) of (A)-5-(3-chlorophenyl)-a-
(4-chlorophenyl)-a-(1-methyl-1H-imidazol-5-yl)-tetrazolo[1,5-
a]quinoline-7-methanamine ethanedioate (1:1) 24a (ee>99%
measured by HPLC). Fraction 2 was converted into the etha-
nedioic salt (1:1) and crystallized from ethanol. The precipitate
was filtered off and dried, yielding 1.85 g (39%) of (B)-5-(3-
chlorophenyl)-a-(4-chlorophenyl)-a-(1-methyl-1H-imidazol-5-
yl)-tetrazolo[1,5-a]quinoline-7-methanamine
ethanedioate
(1:1) 24b. This compound contains 3% of the (A) enantiomer
as measured by HPLC.
31. 43 (7.5 g) was separated into its enantiomers and purified
by column chromatography over Chiralpak AD1 (eluent:
hexane/EtOH 50/50; 15–35 mm). The pure first (A) fractions
were collected and the solvent was evaporated yielding 3.3 g of
residue which was crystallized from CH3CN/DIPE. The pre-
cipitate was filtered off and dried, yielding 2.55 g of (ꢀ)-5-(3-
chlorophenyl)-a-(4-chlorophenyl)-a-(1-methyl-1H-imidazol-5-
yl)-tetrazolo[1,5-a]quinazoline-7-methanamine 43a. This com-
pound contains less than 0.5% of the (+) enantiomer as
measured by HPLC. The second (B) fractions were collected
and evaporated yielding 3.3 g of residue which was crystallized
from CH3CN/DIPE. The precipitate was filtered off and dried
yielding 2.6 g of (+)-5-(3-chlorophenyl)-a-(4-chlorophenyl)-a-
(1-methyl-1H-imidazol-5-yl)-tetrazolo[1,5-a]quinazoline-7-
methanamine 43b. This compound contains 4% of the (ꢀ)
enantiomer as measured by HPLC.
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