J. Kim et al. / Bioorg. Med. Chem. Lett. 23 (2013) 153–157
157
loss of activity. It indicated that an aryl group at R1 region is vital to
Acknowledgments
exhibit antiviral activity. Significant variations in potency were ob-
served depending on the substitution patterns on the phenyl ring.
Meta-position on the phenyl ring with an electron-withdrawing
group is the most influential compared to ortho- and para-posi-
tions. Compound 13 with meta-Cl exhibited 4-fold and 18-fold en-
hanced potency compared to ortho-Cl and para-Cl analogues (19,
20). The antiviral activities among halides at meta-position are
chloro- > fluoro- > bromo-analogues in order. Interestingly, the
introduction of an additional chlorine atom at meta-position suf-
fered from 14-fold reduced antiviral activity (compare 13 and
25). Alkoxy analogues (21, 24) were less potent than chloro com-
pound 13. From these results, the optimal substitution for R1 phe-
nyl ring is the mono-substitution with a chlorine atom at meta-
This work was supported by the National Research foundation
of Korea (NRF) grant funded by the Korea government (MEST)
(No.2012-00011), Gyeonggi-do and KISTI.
References and notes
1. (a) Masur, H.; Michelis, M. A.; Greene, J. B.; Onorato, I.; Stouwe, R. A.; Holzman,
R. S.; Wormser, G.; Brettman, L.; Lange, M.; Murray, H. W.; Cunningham-
Rundles, S. N. Engl. J. Med. 1981, 305, 1431; (b) Barresinoussi, F.; Chermann, J.
C.; Rey, F.; Nugeyre, M. T.; Chamaret, S.; Gruest, J.; Dauguet, C.; Axlerblin, C.;
Vezinetbrun, F.; Rouzioux, C.; Rozenbaum, W.; Montagnier, L. Science 1983,
220, 868; (c) Gallo, R. C.; Salahuddin, S. Z.; Popovic, M.; Shearer, G. M.; Kaplan,
M.; Haynes, B. F.; Palker, T. J.; Redfield, R.; Oleske, J.; Safai, B.; White, G.; Foster,
P.; Markham, P. D. Science 1984, 224, 500.
2. UNAIDS Joint United Nations Programme on HIV/AIDS (UNAIDS); World AIDS
Day Report|2011; ISBN: 978-92-9173-904-2|UNAIDS/JC2216E.
3. (a) De Clercq, E. J. Med. Chem. 2010, 53, 1438; (b) Mehellou, Y.; De Clercq, E. J.
Med. Chem. 2010, 53, 521.
4. (a) Cihlar, T.; Ray, A. S. Antiviral Res. 2010, 85, 39; (b) Este, J. A.; Cihlar, T.
Antiviral Res. 2010, 85, 25.
5. (a) Reynolds, C.; de Koning, C. B.; Pelly, S. C.; van Otterlo, W. A.; Bode, M. L.
Chem. Soc. Rev. 2012, 41, 4657; (b) de Bethune, M. P. Antiviral Res. 2010, 85, 75.
6. (a) Wensing, A. M.; van Maarseveen, N. M.; Nijhuis, M. Antiviral Res. 2010, 85,
59; (b) Abbenante, G.; Fairlie, D. P. Med. Chem. 2005, 1, 71.
7. (a) Tan, J. J.; Liu, C.; Sun, X. H.; Cong, X. J.; Hu, L. M.; Wang, C. X.; Liang, X. J. Mini-
Rev. Med. Chem. 2012, 12, 875; (b) McColl, D. J.; Chen, X. Antiviral Res. 2010, 85,
101.
8. (a) Singh, I. P.; Chauthe, S. K. Expert Opin. Ther. Pat. 2011, 21, 227; (b) Tilton, J.
C.; Doms, R. W. Antiviral Res. 2010, 85, 91.
9. (a) Singh, I. P.; Chauthe, S. K. Expert Opin. Ther. Pat. 2011, 21, 399; (b) Qadir, M.
I.; Malik, S. A. Rev. Med. Virol. 2010, 20, 23.
10. (a) Panos, G.; Samonis, G.; Alexiou, V. G.; Kavarnou, G. A.; Charatsis, G.; Falagas,
M. E. Curr. HIV Res. 2008, 6, 257; Mocroft, A.; Ledergerber, B.; Katlama, C.; Kirk,
O.; Reiss, P.; d’Arminio Monforte, A.; Knysz, B.; Dietrich, M.; Phillips, A. N.;
Lundgren, J. D. Lancet 2003, 362, 22.
position (13, EC50 = 0.27 lM).
The effect of linker moiety in TTPMs was evaluated by replacing
the sulfonyl group with its corresponding carbonyl derivatives and
the results were summarized in Table 3. Ester analogue 28 dis-
played moderate inhibitory activity and its corresponding acid 29
showed 6-fold reduced potency, which was presumably due to
its low cell membrane permeability in our cell-based assay system.
Similar preference for meta-chloro substitution on phenyl ring was
also observed with amide analogues. Amide analogue 31 with m-Cl
showed 9-fold and 43-fold higher potency than other amide ana-
logues with o-Cl 30 and p-Cl 32, respectively. Ketone derivative
37 showed comparable activity. Based on these results, other linker
moieties could be further utilized to improve antiviral activities
and drug-like properties of TTPM derivatives.
After the preliminary SAR with R1, R2 and linker modification,
we further investigated the R2 region with substituted phenyl
derivatives 38–48 as shown in Table 4. Unsubstituted phenyl ana-
logue 38 exhibited equipotent antiviral activity compared to com-
pound 13 with morpholine. Although no significant variations in
activities were observed on the analogues containing electron-
withdrawing group (40, 41, and 42), the derivatives with elec-
tron-donating group (43, 44, and 45), clearly displayed the impact
of substitutions on the phenyl ring. para-Methoxy analogue 45
exhibited 21-fold and 5-fold enhanced potency compared to the
corresponding ortho- and meta-methoxy analogues (43, 44),
respectively. Increasing the size of alkyl group from methoxy 45
to ethoxy 46 led to 8-fold reduction in activity. In case of hydroxy
analogue 47, it suffered from increased cytotoxicity. Surprisingly,
compound 48 with para-dimethylamino group showed greatly re-
duced inhibitory activity, indicating para-methoxy substitution is
optimal for phenyl ring to obtain significant activity with accept-
able therapeutic index.
11. (a) Paredes, R.; Clotet, B. Antiviral Res. 2010, 85, 245; (b) Kiertiburanakul, S.;
Sungkanuparph, S. Curr. HIV Res. 2009, 7, 273.
12. (a) Esplugues, J. V.; Blas-Garcia, A.; Apostolova, N. Curr. Med. Chem. 2011, 18,
2186; (b) Hawkins, T. Antiviral Res. 2010, 85, 201; (c) Montessori, V.; Press, N.;
Harris, M.; Akagi, L.; Montaner, J. S. G. Can. Med. Assoc. J. 2004, 170, 229.
13. Kim, H. J.; Doddareddy, M. R.; Choo, H.; Cho, Y. S.; No, K. T.; Park, W. K.; Pae, A.
N. J. Chem. Inf. Model. 2008, 48, 197.
14. Ivachtchenko, A. V.; Golovina, E. S.; Kadieva, M. G.; Koryakova, A. G.;
Kovalenko, S. M.; Mitkin, O. D.; Okun, I. M.; Ravnyeyko, I. M.; Tkachenko, S.
E.; Zaremba, O. V. Bioorg. Med. Chem. 2010, 18, 5282.
15. Anderson, M. O.; Zhang, J.; Liu, Y.; Yao, C.; Phuan, P.-W.; Verkman, A. S. J. Med.
Chem. 2012, 55, 5942.
16. El-Osaily, Y. A.; Sarhan, A. A. O.; El-Dean, A. M. K. Phosphorus, Sulfur Silicon Relat.
Elem. 2007, 182, 121.
17. Curti, C.; Laget, M.; Carle, A. O.; Gellis, A.; Vanelle, P. Eur. J. Med. Chem. 2007, 42,
880.
18. Zadorozny, A. V.; Kovtunenko, V. A. Chem. Heterocycl. Compd. 2009, 45, 489.
19. Lared, M.; Moberg, C.; Hallberg, A. Acc. Chem. Res. 2002, 35, 717.
20. HIV full replication assay: CEMx174-LTR-GFP cells (clone CG8) were seeded
with a microplate dispenser (WellMate; Thermo Scientific Matrix; USA) at a
density of 4000 cells/well into 384-well glass plates (Evotec; Hamburg,
In summary, a series of TTPM derivatives was synthesized and
evaluated as HIV-1 replication inhibitors in vitro. From preliminary
SAR in a cell-based full replication assay, we discovered aryl-
substituted TTPM derivatives (38, 44, and 45), which exhibited sig-
nificant inhibitory activity along with acceptable safety margins.
Mode of action and further optimization of this novel class of
anti-HIV agents is currently under investigation.
Germany) pre-dispensed with 10 lL of compound diluted in DMSO and
incubated for 1 h at 37 °C, 5% CO2. Then cells were infected with HIV-1LAI at a
multiplicity of infection (MOI) of 3 and incubated for 5 days at 37 °C, 5% CO2.
Fluorescence intensities were then measured using a multilabel plate reader
(Victor3; PerkinElmer, Inc.; USA). And see Sommer, P.; Vartanian, J. P.;
Wachsmuth, M.; Henry, M.; Guetard, D.; Wain-Hobson, S. J. Mol. Biol. 2004,
344, 11.