New HIV-1 replication inhibitors of the styryquinoline class bearing aroyl/acyl groups at the C-7 position: Synthesis and biological activity

Article abstract of DOI:10.1016/j.bmcl.2005.06.036

Novel variants of HIV-1 replication inhibitors of the styrylquinoline class harboring aroyl/acyl group at the C-7 position have been synthesized. In sharp contrast with styrylquinolines bearing a carboxylic acid group at C-7, these compounds proved to be inactive toward HIV-1 integrase in in vitro assays.

Full text of DOI:10.1016/j.bmcl.2005.06.036

Bioorganic & Medicinal Chemistry Letters 15 (2005) 4019–4022
New HIV-1 replication inhibitors of the styryquinoline class bearing
aroyl/acyl groups at the C-7 position: Synthesis and
biological activity
a
Marie Normand-Bayle, Christophe Benard, Fatima Zouhiri,
a
a,b
´
Jean-Franc¸ois Mouscadet, Herve Leh, Claire-Marie Thomas, Gladys Mbemba,
c
b
b
c
´
Didier Desmae¨lea,* and Jean dÕAngeloa,*
a
´ ´
Unite Associee au CNRS, UMR 8076, Faculte de Pharmacie, 5, rue J.-B. Clement, 92290 Chatenay-Malabry, France
´
´ ´
BioAlliance Pharma SA, 59 bd du General Martial Valin, 75015 Paris, France
´
ˆ
b
c
´ ´ ´
Unite Associee au CNRS, UMR 8113, Ecole Normale Superieure de Cachan, 94235 Cachan, France
Received 18 April 2005; revised 6 June 2005; accepted 7 June 2005
Available online 5 July 2005
Abstract—Novel variants of HIV-1 replication inhibitors of the styrylquinoline class harboring aroyl/acyl group at the C-7 position
have been synthesized. In sharp contrast with styrylquinolines bearing a carboxylic acid group at C-7, these compounds proved to be
inactive toward HIV-1 integrase in in vitro assays.
Ó 2005 Elsevier Ltd. All rights reserved.
1. Introduction
Although the exact mechanism by which drug 1 and
analogs exert their inhibitory potency remains un-
known, it has been recently proposed that such drugs
might act prior to integration by preventing viral
DNA integrase binding.5 Thus, SQLs constitute a un-
ique class of integrase inhibitors, distinct from diketo
acids (illustrated by L 731,988, 2), which affect viral
DNA integration.3a Within the framework of SQLs,
we have identified the salicylic acid moiety at C-7 and
C-8 of the quinoline ring, and the 40-OH of the ancillary
aromatic nucleus as critical pharmacophores for antivi-
ral activity.4b Here, we report the preliminary results of
our expanded SAR investigation of SQLs directed to-
ward the replacement of the carboxylic group at C-7
by a variety of aroyl/acyl moieties as in 3. The new de-
signed SQLs were found to be inactive against HIV-1 in-
tegrase but some of them inhibited the HIV-1 replication
in cell culture. Note that naphthyridine ketones 4, a re-
cent class of HIV-1 replication inhibitors and SQLs of
type 3, belong to the same chemical family (Fig. 1).6
The substantial incidence of resistance observed in ther-
apy-experienced patients and newly acquired HIV-1
infections underscores the need for new antiretroviral
agents. All oral agents licensed to treat HIV-1 diseases
target two of the three essential, virally encoded enzymes,
reverse transcriptase and protease.1 The third enzyme,
integrase, inserts the viral DNA into the cellular genome
through a multi-step process that includes two catalytic
reactions, 30-endonucleolytic processing of the viral
DNA ends, and joining of the viral and cellular DNAs
(strand transfer).2 Although numerous classes of HIV-1
integrase inhibitors have been identified, only a few of
them proved to be active against HIV-1 replication.3
We have reported that polyhydroxylated styrylquino-
lines (SQLs), exemplified by 1, are potent HIV-1 inte-
grase inhibitors in in vitro experiments, block the
replication of HIV-1 in cell culture, and are devoid of
cytotoxicity.4
2. Chemistry
Keywords: Antivirals; Enzyme inhibitors; Metalation; Acylation;
Quinolines.
It appeared that a sequence directed to the synthesis of
SQLs substituted at C-7 by aroyl/acyl moieties should
require at the outset the elaboration of 7-bromo-8-
*
Corresponding authors. Tel.: +33 1 46 48 57 53; fax: +33 0 146
83 5752; e-mail addresses: didier.desmaele@cep.u-psud.fr; jean.
dangelo@cep.u-psud.fr
0960-894X/$ - see front matter Ó 2005 Elsevier Ltd. All rights reserved.
doi:10.1016/j.bmcl.2005.06.036

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M. Normand-Bayle et al. / Bioorg. Med. Chem. Lett. 15 (2005) 4019–4022
3. Biological activity of the target molecules
Cellular antiviral IC50 was determined as the drug con-
centration that inhibits 50% of viral particles infectivity
in standard MAGI assay.5b TC50 was the drug concen-
tration that corresponds to 50% of cell survival as deter-
mined by a standard MTT assay.4b The results are
illustrated in Table 1. At first glance, the present mole-
cules can be categorized as inactive, cytotoxic, and ac-
tive. Within the active compound series, five of them
exhibit IC50 values ranging from 2 to 6 lM, with TC val-
ues in the range of 60–100 lM: 3,4-difluorophenyl, para-
hydroxyphenyl, ortho-nitrophenyl, para-nitrophenyl,
and 3-pyridyl derivatives 3b, 3d, 3e, 3g, and 3j, respec-
tively. Although the great structural diversity of the
above molecules rules out the identification of a com-
mon definitive pharmacophore, some comments can be
made, based on the present SAR investigation.
Figure 1.
hydroxyquinaldine 6, starting from readily available
8-hydroxyquinaldine 5.
However, bromination of 5 under standard conditions
proved to be non-regioselective, giving mixtures of 5-
bromo-, 7-bromo-, and 5,7-dibromo-8-hydroxyquinal-
dines. In contrast, when the experimental protocol
developed by Pearson (Br2, t-BuNH2, ꢀ78 °C)7 was ap-
plied, the desired 7-bromo derivative 6 was obtained as a
single product in 74% yield. Perkin-type condensation of
6 with 3,4-dihydroxybenzaldehyde 7 (refluxing Ac2O,
then H2O, pyridine, 100 °C) next furnished styrylquino-
line 8 (66% yield) that was converted into trimethoxy
derivative 9 (K2CO3, MeI, DMF, 40 °C, 62% yield).
At this juncture, we stood ready to proceed to the intro-
duction of the desired aroyl/acyl group at C-7. For that
In this respect, there existed a striking geometrical fit
requirement for antiviral activity versus cytotoxicity.
By way of illustration, replacement of the para-hydroxy-
phenyl moiety of 3d by an ortho-substituted counterpart
(3c) results in dramatic cytotoxicity. Likewise, meta-
nitrophenyl derivative 3f proved to be much more cyto-
toxic than the ortho- and para- substituted analogs 3e
and 3g. In addition, while 3-pyridyl derivative 3j exhibits
no significant cytotoxicity, the corresponding ortho and
para isomers (3i and 3k, respectively) were found to be
moderately to highly cytotoxic. A last remark can be
made, regarding the three isomeric compounds 3o–q,
in which a carboxylic acid is directly linked to the phenyl
moiety: in contrast with the ‘‘unsubstituted’’ derivatives
3a and 3l, they proved to be almost non-cytotoxic. How-
ever, no significant antiviral activity was observed with
these compounds.
purpose, 9 was submitted to Br/Li exchange according
8
´
to the Queguiner procedure (PhLi, Et2O, ꢀ78 °C),
and the resulting lithio derivative was condensed with
electrophiles 10a–q9 giving either alcohols 11a–n (45–
80% yield) or ketones 12o–q (20–25% yield). Alcohols
11a–n were further oxidized (MnO2) into corresponding
ketones 12a–n with a 50–90% yield. Finally, treatment of
12a–n with BBr3 in CH2Cl2 at 20 °C or 12o–q with 48%
aqueous HBr at reflux delivered our goals 3a–q (35–60%
yield) (Scheme 1).10
To precise the nature of ex vivo interacting target(s) of
the above ÔactiveÕ molecules, their in vitro anti-HIV-1 in-
tegrase potency was evaluated next. Surprisingly, in
Scheme 1. Synthesis of compounds 3a–q, reagents and conditions: (a) Br2, t-BuNH2, toluene, ꢀ78 to 20 °C, 74%; (b) 2 equiv 7, Ac2O, 140 °C, 18 h;
(c) H2O, pyridine, 100 °C, 2 h, 66%; (d) K2CO3, 10 equiv CH3I, acetone, DMF, 70 °C, 12 h, 62%; (e) i—2.5 equiv PhLi, cyclohexane, Et2O, ꢀ78 °C,
ii—1.25 equiv 10a–n, THF, HMPA, ꢀ78 to 20 °C; (f) i—2.5 equiv PhLi, cyclohexane, Et2O, ꢀ78 °C, ii—1.25 equiv 10o–q, THF, HMPA, ꢀ78 to
20 °C; (g) 10 equiv MnO2, ClCH2CH2Cl, 70 °C, 8 h; (h) 48% aqueous HBr, 120 °C, 12 h for 12o–q or BBr3, CH2Cl2, ꢀ78 to 20 °C, 8 h for 12a–n.

M. Normand-Bayle et al. / Bioorg. Med. Chem. Lett. 15 (2005) 4019–4022
Table 2. In vitro activity of C-7-modified styrylquinolines (lM)a
4021
Table 1. Antiviral activity and toxicity of C-7-modified styrylquino-
lines (lM)
Compound
1
Compound
Biological activity IC50
30-processing
Strand transfer
R
IC50
1
TC50
>100
1
2
>100
>100
>100
100
1
>100
>100
70
3b
3d
3e
3g
3j
3a
3b
3c
NRa
3
63
1
>100
>100
4
>100
a Drug concentration that inhibits 50% of the recombinant integrase
activity in standard 30-processing and strand transfer assays.
NR
in ex vivo experiments (Table 2). The mode of action of
this new class of antiretroviral agents is currently under
investigation.
3d
3e
3f
6
87
70
4
Acknowledgment
M. N.-B. thanks ANRS (France) for the award of a
fellowship.
0,5
2
1,5
60
3g
3h
3i
References and notes
1. De Clercq, E. Med. Res. Rev 2002, 22, 531.
2. Brown, P. O. Curr. Top. Microbiol. Immunol. 1990, 157,
19.
60
NR
2
90
3. (a) Espeseth, A. S.; Felock, P.; Wolfe, A.; Witmer, M.;
Grobler, J.; Anthony, N.; Egbertson, M.; Melamed, J. Y.;
Young, S.; Hamill, T.; Cole, J. L.; Hazuda, D. J. Proc.
Natl. Acad. Sci. U.S.A. 2000, 97, 11244; (b) Hazuda, D. J.;
Anthony, N. J.; Gomez, R. P.; Jolly, S. M.; Wai, J. S.;
Zhuang, L.; Fisher, T. E.; Embrey, M.; Guare, J. P., Jr.;
Egbertson, M. S.; Vacca, J. P.; Huff, J. R.; Felock, P. J.;
Witmer, M. V.; Stillmock, K. A.; Danovich, R.; Grobler,
J.; Miller, M. D.; Espeseth, A. S.; Jin, L.; Chen, I.-W.; Lin,
J. H.; Kassahun, K.; Ellis, J. D.; Wong, B. K.; Xu, W.;
Pearson, P. G.; Schlief, W. A.; Cortese, R.; Emini, E.;
Summal, V.; Holloway, M. K.; Young, S. D. Proc. Natl.
Acad. Sci. U.S.A. 2004, 101, 11233; (c) Costi, R.; Di
Santo, R.; Artico, M.; Massa, S.; Ragno, R.; Loddo, R.;
La Colla, M.; Tramontano, E.; La Colla, P.; Pani, A.
Bioorg. Med. Chem. 2004, 12, 199; (d) Middleton, T.; Lim,
H. B.; Montgomery, D.; Rockway, T.; Tang, H.; Cheng,
X.; Lu, L.; Mo, H.; Kohlbrenner, W. E.; Molla, A.; Kati,
W. M. Antiviral Res. 2004, 64, 35; (e) Pommier, Y.;
Johnson, A. A.; Marchand, C. Nat. Rev. 2005, 236,
March.
15
3j
>100
4
3k
NR
3l
NR
2
1
7
3m
3n
3o
3p
3q
n-C8H17
-
5
10
4. (a) Mekouar, K.; Mouscadet, J.-F.; Desmae¨le, D.; Subra,
´
35
63
40
>100
>100
80
F.; Leh, H.; Savoure, D.; Auclair, C.; dÕAngelo, J. J. Med.
Chem. 1998, 41, 2846; (b) Zouhiri, F.; Mouscadet, J.-F.;
´
Mekouar, K.; Desmae¨le, D.; Savoure, D.; Leh, H.; Subra,
F.; Le Bret, M.; Auclair, C.; dÕAngelo, C. J. Med. Chem.
2000, 43, 1533; (c) Ouali, M.; Laboulais, C.; Leh, H.; Gill,
D.; Desmae¨le, D.; Mekouar, K.; Zouhiri, F.; dÕAngelo, J.;
Auclair, C.; Mouscadet, J.-F.; Le Bret, M. J. Med. Chem.
2000, 43, 1949; (d) F. Zouhiri, F.; Desmae¨le, D.; dÕAngelo,
J.; Ourevitch, M.; Mouscadet, J.-F.; Leh, H.; Le Bret, M.
Tetrahedron Lett. 2001, 42, 8189; (e) Polanski, J.; Zouhiri,
F.; Jeanson, L.; Desmae¨le, D.; dÕAngelo, J.; Mouscadet,
J.-F.; Gieleciak, R.; Gasteiger, J.; Le Bret, M. J. Med.
a NR, IC50 not reached.
sharp contrast with SQLs of type 1 harboring a carbox-
ylic acid group at C-7, compounds 3b, 3d, 3e, 3g, and 3j
proved to be inactive in both 30-processing and strand
transfer assays, ruling out integration as the step target
´
Chem. 2002, 45, 4647; (f) Benard, C.; Zouhiri, F.;
Normand-Bayle, M.; Danet, M.; Desmae¨le, D.; Leh, H.;
Mouscadet, J.-F.; Mbemba, G.; Thomas, C.-M.; Bonnen-
fant, S.; Le Bret, M.; dÕAngelo, J. Bioorg. Med. Chem.

4022
M. Normand-Bayle et al. / Bioorg. Med. Chem. Lett. 15 (2005) 4019–4022
´
Lett. 2004, 14, 2473; (g) Zouhiri, F.; Danet, M.; Benard,
d 194.7 (CO), 156.1 (C), 153.3 (dd, JCF = 253 Hz, 13 Hz,
CF), 153.2 (C), 150.3 (dd, JCF = 235 Hz, 14 Hz, CF), 147.8
(C), 146.5 (C), 139.1 (C), 137.4 (CH), 136.9 (CH), 136.5
(dd, J = 4.9 Hz, 3.7 Hz, C), 129.9 (CH), 128.9 (C), 128.1
(dd, JCF = 7.8 Hz, 2.9 Hz, CH), 126.8 (CH), 124.8 (C),
123.7 (CH), 121.0 (C); 120.8 (CH), 119.3–118.5 (3CH)
116.8 (CH), 115.0 (CH): Anal. Calcd. for C24H15F2NO4.-
H2O: C, 65.90; H, 3.92; N, 3.20. Found C, 65.75; H, 4.10;
N, 3.41. 3d: red solid, mp 245 °C; IR (neat, cmꢀ1) m 3600–
C.; Normand-Bayle, M.; Mouscadet, J.-F.; Leh, H.;
Thomas, C.-M.; Mbemba, G.; dÕAngelo, J.; Desmae¨le,
D. Tetrahedron Lett. 2005, 46, 2201.
5. (a) Deprez, E.; Barbe, S.; Kolaski, M.; Leh, H.; Zouhiri,
F.; Auclair, C.; Brochon, J.-C.; Le Bret, M.; Mouscadet,
J.-F. Mol. Pharmacol. 2004, 65, 85; (b) Bonnenfant, S.;
Thomas, M.-C.; Vita, C.; Subra, F.; Deprez, E.; Zouhiri,
F.; Desmae¨le, D.; dÕAngelo, J.; Mouscadet, J.-F.; Leh, H.
J. Virol. 2004, 78, 5728.
1
2500, 1580, 1509; H NMR (DMSO-d6, 200 MHz) d 8.60
6. Zhuang, L.; Wai, J. S.; Embrey, M. W.; Fisher, T. E.;
Egbertson, M. S.; Payne, L. . S.; Guare, J. P., Jr.; Vacca, J.
P.; Hazuda, D. J.; Felock, P. J.; Wolfe, A. L.; Stillmock,
K. A.; Witmer, M. V.; Moyer, G.; Schleif, W. A.;
Gabryelski, L. J.; Leonard, Y. M.; Lynch, J. J., Jr.;
Michelson, S. R. J. Med. Chem. 2003, 46, 453.
(d, J = 8.7 Hz, 1H), 8.14 (d, J = 8.7 Hz, 1H), 8.13 (d,
J = 16.4 Hz, 1H), 7.75 (d, J = 8.6 Hz, 2H), 7.60 (d,
J = 8.7 Hz, 1H), 7.51 (d, J = 8.6 Hz, 1H), 7.45 (d,
J = 16.4 Hz, 1H), 7.18 (d, J = 1.5 Hz, 1H), 7.09 (dd,
J = 8.0 Hz, 1.5 Hz, 1H), 6.92 (d, J = 8.7 Hz, 2H), 6.88 (d,
J = 8.0 Hz, 1H). 3e: brown solid, mp 188 °C; IR (neat,
1
7. Pearson, D. E.; Wysong, R. D.; Breder, C. V. . J. Org.
Chem. 1967, 32, 2358.
cmꢀ1) m 3500–2500, 1617, 1598, 1522; H NMR (DMSO-
d6, 200 MHz)
d 8.35 (d, J = 8.6 Hz, 1H), 8.33 (d,
´
´
8. Trecourt, F.; Mallet, M.; Mongin, F.; Queguiner, G.
J = 8.0 Hz, 1H), 8.11 (d, J = 16.1 Hz, 1H), 8.00–7.80 (m,
4H), 7.68 (d, J = 7.3 Hz, 1H), 7.47 (d, J = 8.7 Hz, 1H),
7.16 (d, J = 16.1 Hz, 1H), 7.12 (br s, 1H), 7.01 (d,
J = 8.1 Hz, 1H), 6.81 (d, J = 8.1 Hz, 1H); 13C NMR
(DMSO-d6, 50 MHz) d 192.9 (CO), 156.5 (C), 155.9 (C),
147.8 (C), 146.6 (C), 146.4 (C), 139.8 (C), 139.3 (C), 136.7
(CH), 136.5 (CH), 135.7 (CH), 131.2 (CH), 130.9 (C),
128.9 (CH), 128.8 (C), 126.1 (CH), 124.9 (CH), 124.7
(CH), 124.1 (CH), 120.8 (CH), 118.6 (C),118.4 (CH), 116.7
(CH), 114.8 (CH). 3g: red solid, mp 153 °C; IR (neat,
Synthesis 1995, 1159.
9. 10a: benzaldehyde; 10b: 3,4-difluorobenzaldehyde; 10c: 2-
methoxybenzaldehyde; 10d: 4-methoxybenzaldehyde; 10e:
2-nitrobenzaldehyde; 10f: 3-nitrobenzaldehyde; 10g: 4-
nitrobenzaldehyde; 10h: 4-methyl-3-nitrobenzaldehyde;
10i: 2-pyridine-carboxaldehyde; 10j: 3-pyridinecarboxal-
dehyde; 10k: 4-pyridinecarboxaldehyde; 10l: 1-naphtha-
ldehyde; 10m: dihydrocinnamaldehyde; 10n: nonanal; 10o:
phthalic anhydride; 10p: 3-cyano-N-methoxy-N-methyl-
benzamide (prepared through condensation of 3-cya-
nobenzoyl chloride with N,O-dimethyl-hydroxylamine in
the presence of pyridine); 10q: 4-cyano-N-methoxy-N-
methyl-benzamide (prepared by analogy with 10p, starting
from 4-cyanobenzoyl chloride).
10. Characterization data for compounds 3b, 3d, 3e, 3g and 3j.
3b: greenish solid, mp 178 °C; IR (neat, cmꢀ1) m 3600–
2500, 1617, 1588, 1544; 1H NMR (DMSO-d6, 200 MHz) d
8.345 (d, J = 8.8 Hz, 1H), 8.08 (d, J = 16.2 Hz, 1H), 7.95-
7.80 (m, 2H), 7.75–7.42 (m, 4H), 7.21 (d, J = 16.2 Hz, 1H),
7.17 (br s, 1H), 7.05 (br d, J = 7.9 Hz, 1H), 6.85 (d,
J = 7.9 Hz, 1H); 19F NMR (CDCl3, 188 MHz) d ꢀ130.2
(m, 1F), ꢀ136.1 (m, 1F), 13C NMR (DMSO-d6, 50 MHz)
1
cmꢀ1) m 3500–2500, 1612, 1592, 1512; H NMR (DMSO-
d6, 200 MHz) d 8.45-8.35 (m, 3H), 8.15-8.04 (m, 3H), 7.91
(d, J = 8.6 Hz, 1H), 7.60 (d, J = 8.9 Hz, 1H), 7.49 (d,
J = 8.9 Hz, 1H), 7.21 (d, J = 16.0 Hz, 1H), 7.15 (br s, 1H),
7.03 (br d, J = 8.2 Hz, 1H), 6.83 (d, J = 8.2 Hz, 1H). 3j:
brown solid, mp 241 °C; IR (neat, cmꢀ1) m 3200–2200,
1605, 1588, 1509, 1416; 1H NMR (DMSO-d6, 200 MHz) d
9.29 (br s, 1OH), 9.08 (br s, 1OH), 8.96 (s, 1H), 8.84 (d,
J = 3.7 Hz, 1H), 8.36 (d, J = 8.6 Hz, 1H), 8.20 (d,
J = 8.1 Hz, 1H), 8.07 (d, J = 16.1 Hz, 1H), 7.88 (d,
J = 8.6 Hz, 1H), 7.62–7.45 (m, 3H), 7.20 (d, J = 16.1 Hz,
1H), 7.10 (br s, 1H), 6.99 (br d, J = 8.5 Hz, 1H), 6.79 (d,
J = 8.5 Hz, 1H).