946
S. Mavel et al. / Bioorg. Med. Chem. 10 (2002) 941–946
Enraf-Nonius diffractometer equipped with a graphite
monochromator for ymax=60ꢁ:ꢀ10ꢅhꢅ10, 0ꢅkꢅ11,
ꢀ13ꢅlꢅ13 and a o ꢀ2y scan. Three standard reflec-
tions were used to monitor the data collection and
detect any decrease of intensity (5 1ꢀ9, 3 5ꢀ6, 4 4ꢀ1);
the crystal absorption correction was performed using
the ꢀ scan technique.15 There were 3191 independent
reflections of which 2642 were considered as observed
(Iꢂ2s(I) and Rint=0.029). The crystal structure was
solved and refined by full-matrix anisotropic least-
squares on F2 with using the SHELX97 program.16
Scattering factors were taken from the International
Tables for Crystallography.17 The hydrogen atoms were
introduced in their theoretical positions and allowed to
ride with the atoms to which they are attached. The final
reliability factors are: R=0.038, wR=0.096 and the
goodness of fit on F2 was equal to 1.032. The weight was
equal to: w=1/[s2(Fo2)+(0.0383P)2+0.3458P] where
P=(Fo2 +2Fc2)/3. The minimum and maximum resi-
dual density were:-0.180 and 0.196 e.Aꢀ3, respectively.
zoek (FWO), Vlaanderen and the Geconcerteerde
Onderzoeksacties (GOA), Vlaamse Gemeenschap.
References and Notes
1. Fowler, K. B.; Stagno, S.; Pass, R. F.; Britt, W. J.; Boll,
T. J.; Alford, C. A. N. Engl. J. Med. 1992, 326, 663.
2. Tyms, A. S.; Taylor, D. L.; Parkin, J. M. J. Antimicrob.
Chemother. 1989, 23 (A), 89.
3. Elhakmaoui, A.; Gueiffier, A.; Milhavet, J.-C.; Blache, Y.;
Chapat, J.-P.; Chavignon, O.; Teulade, J.-C.; Snoeck, R.;
Andrei, G.; De Clercq, E. Bioorg. Med. Chem. Lett. 1994, 4,
1937.
4. Gueiffier, A.; Blache, Y.; Chapat, J. P.; Elhakmaoui, A.;
Essassi, E. M.; Andrei, G.; Snoeck, R.; De Clercq, E.; Cha-
vignon, O.; Teulade, J. C.; Fauvelle, F. Nucleosides Nucleo-
tides 1995, 14, 551.
5. Gueiffier, A.; Lhassani, M.; Elhakmaoui, A.; Snoeck, R.;
Andrei, G.; Chavignon, O.; Teulade, J. C.; Kerbal, A.; Essassi,
E. M.; Debouzy, J. C.; Witvrouw, M.; Blache, Y.; Balzarini,
J.; De Clercq, E.; Chapat, J. P. J. Med. Chem. 1996, 39, 2856.
6. Gueiffier, A.; Mavel, S.; Lhassani, M.; Elhakmaoui, A.;
Snoeck, R.; Andrei, G.; Chavignon, O.; Teulade, J. C.; Witv-
rouw, M.; Balzarini, J.; De Clercq, E.; Chapat, J. P. J. Med.
Chem. 1998, 41, 5108.
7. Spek, A. L. Platon99, Program for Drawing Crystal and
Molecular Diagrams 1999.
8. Mavel, S.; Renou, J. L.; Galtier, C.; Snoeck, R.; Andrei,
G.; Balzarini, J.; De Clercq, E.; Gueiffier, A. Arzneim.-Forsch.
(Drug Res.) 2001, 51, 304.
9. Teulade, J. C.; Escale, R.; Rossi, J. C.; Chapat, J. P.;
Grassy, G.; Payard, M. Austr. J. Chem. 1982, 35, 1761.
10. Chezal, J. M.; Delmas, G.; Mavel, S.; Elakmaoui, H.;
Metin, J.; Diez, A.; Blache, Y.; Gueiffier, A.; Rubiralta, M.;
Teulade, J. C.; Chavignon, O. J. Org. Chem. 1997, 62, 4085.
11. Kaye, I. A.; Klein, H. C.; Burlant, W. J.; Kogon, I. C. J.
Amer. Chem. Soc. 1952, 74, 3676.
Antiviral activity assays
Human cytomegalovirus (HCMV) (AD-169, Davis)
strains were exposed to human embryonic lung HEL
cell cultures. Briefly, confluent cell cultures in microtiter
trays were inoculated with 100 plaque forming units
(PFU). After 1 h virus adsorption, residual virus was
removed, and the cell cultures were incubated in the
presence of varying concentrations (400, 200, 100, . . .mg/
mL) of the test compounds. Viral cytopathicity was
recorded as soon as it reached completion in the control
virus-infected cell cultures. Inhibition of HCMV by the
test compounds was compared with cidofovir and gan-
ciclovir as the reference compounds. Antiviral activity is
expressed as the compound concentration required to
inhibit viral cytopathicity by 50% (IC50).
12. Deady, L. W.; Stanborough, M. S. Aust. J. Chem. 1981,
34, 1295.
13. Barlin, G. B.; Davies, L. P.; Ireland, S. J.; Ngu, M. M. L.
Aust. J. Chem. 1989, 42, 1735.
14. Semple, G.; Ryder, H.; Kendrick, D. A.; Szelke, M.; Ohta,
M.; Satoh, M.; Nishida, A.; Akuzawa, S.; Miyata, K. Bioorg.
Med. Chem. Lett. 1996, 6, 51.
15. North, A. C. T.; Phillips, D. C.; Matthews, F. S. Acta
Cryst. A24 1968, 351.
16. Sheldrick, G. M. SHELX97, Program for the Determina-
tion and the Refinement of Crystal Structures; University of
Gottingen: Gottingen, Germany, 1997.
17. International Tables for X-Ray Crystallography. Kynoch:
Birmingham, 1989; Vol. C.
18. De Clercq, E.; Descamps, J.; Verhelst, G.; Walker, R. T.;
Jones, A. S.; Torrence, P. F.; Shugar, D. J. Infect. Dis. 1980,
141, 563.
19. De Clercq, E.; Holy, A.; Rosenberg, I.; Sakuma, T.; Bal-
zarini, J.; Maudgal, P. C. Nature 1986, 323, 464.
20. Balzarini, J.; Naesens, L.; Slachmuylders, J.; Niphuis, H.;
Rosenberg, I.; Holy, A.; Schellekens, H.; De Clercq, E. Aids
1991, 5, 21.
Cytostatic activity assays
The cytostatic assays were performed as previously
described.18ꢀ20 Briefly, 100-mL aliquots of HEL cell sus-
pensions were added to the wells of a 96-well microtiter
plate containing 100 mL of varying concentrations of the
test compounds. After 3-days incubation period at 37ꢁC
in a humidified CO2-controled incubator, the number of
viable cells was determined using a Coulter Counter.
Cytostatic activity is expressed as the compound con-
centration that reduced the number of viable cells by 50%
(CC50). The cytotoxicity measurements were based on
microscopically visible morphological alterations of the
HEL cell culture: cytotoxicity was defined as the mini-
mum cytotoxic concentration (MCC) required to cause a
microscopically detectable alteration of cell morphology.
21. Buu-Hoi, N. P.; Hoan, N. Recl. Trav. Chim. P. B 1949, 68,
441.
22. Loiseau, P. R.; Payard, M.; Grassy, G.; Dornelles Pinto,
Z.; Advenier, C.; Gnassounou, J. P.; Adam, Y. Eur. J. Med.
Chem. 1987, 22, 457.
23. Buu-Hoi, N. P.; Hoan, Ng.; Rayer, R. Bull. Soc. Chim. Fr
1950, 489.
24. Abignente, E.; De Caprariis, P.; Patscot, R.; Sacchi, A. J.
Heterocyclic Chem. 1986, 23, 1031.
Acknowledgements
We thank Anita Campsand Lies Vandenheurck for
excellent technical assistance and Doctor J. C. Debouzy
(CRSSA, La Tronche, France) for performing 400 MHz
spectra of 1c. These investigations were supported by
grants from the Fonds voor Wetenschappelijk Onder-