R. E. Sammelson et al. / Bioorg. Med. Chem. Lett. 13 (2003) 2509–2512
2511
we found no activity. However, we hope that further iso-
xazole derivatives synthesized on the basis of this study
may show improved properties against wild type as well
as mutant CFTR.
In conclusion, our work has identified a new class of
CFTR activators; an important result since increasing
the spectrum of CFTR activators is essential in gaining
a comparative perspective and in establishing possible
consensus pharmacophores. This may in turn prove
important in defining the mechanism of activation as
well as in identifying the putative binding site.
Acknowledgements
This study was supported by the National Science
Foundation, the Cystic Fibrosis Foundation, and an
R. Bryan Miller Graduate Fellowship (RES).
References and Notes
1. (a) Hwang, T.-C.; Lu, L.; Zeitlin, P. L.; Gruenert, D. C.;
Huganir, R.; Guggino, W. B. Science 1989, 244, 1351. (b)
Riordan, J. R.; Rommens, J. M.; Kerem, B.; Alon, N.; Roz-
mahel, R.; Grzelczak, Z.; Zielenski, J.; Lok, S.; Plavsic, N.;
Chou, J.-L.; Drumm, M. L.; Iannuzzi, M. C.; Collins, F. S.;
Tsui, L.-C. Science 1989, 245, 1066. (c) Kerem, B.; Rommens,
J. M.; Buchanan, J. A.; Markiewicz, D.; Cox, T. K.; Chakra-
varti, A.; Buchwald, M.; Tsui, L.-C. Science 1989, 245, 1073.
(d) Collins, F. S. Science 2001, 256, 774. (e) Al-Nakkash, L.;
Hu, S.; Li, M.; Hwang, T.-C. J. Pharmacol. Exp. Ther. 1992,
296, 464.
2. Schwiebert, E. M.; Benos, D. J.; Egan, M. E.; Stutts, M. J.;
Guggino, W. B. Physiol. Rev. 1999, 79, S145.
3. Illek, B.; Lizarzaburu, M. E.; Lee, V.; Nantz, M. H.;
Kurth, M. J.; Fischer, H. Am. J. Physiol. 2000, 279,
C1838.
4. Goddard, C. A.; Evans, M. J.; Colledge, W. H.
Am. J. Physiol. 2000, 279, C383.
5. Gribkoff, V. K.; Champigny, G.; Barby, P.; Dworetzky,
S. I.; Meanwell, N. A.; Lazdunski, M. J. Biol. Chem. 1994,
269, 10983.
6. Becq, F.; Metty, Y.; Gray, M. A.; Galietta, L. J. V.; Dor-
mer, R. L.; Merten, M.; Metaye, T.; Chappe, V.; Marvingt-
Mounir, C.; Zegarra-Moran, O.; Tarran, R.; Bulteau, L.;
Derand, R.; Pereira, M. M.; McPherson, M. A.; Rogier, C.;
Joffre, M.; Argent, B. E.; Sarrouilhe, D.; Kammouni, W.;
Figarella, C.; Verrier, B.; Gola, M.; Vierfond, J. M. J. Biol.
Chem. 1999, 274, 27415.
7. Jayaraman, S.; Haggie, P.; Wachter, R. M.; Remington,
S. J.; Verkman, A. S. J. Biol. Chem. 2000, 275, 6047.
8. Galietta, L. J. V.; Springsteel, M. F.; Eda, M.; Niedzinski,
E. J.; By, K.; Haddadin, M. J.; Kurth, M. J.; Nantz, M. H.;
Verkman, A. S. J. Biol. Chem. 2001, 276, 19723.
9. Percent in parenthesis for all figures and Schemes provide
the relative CFTR activation where the activation for genis-
tein, a known activator, is standardized to 100%.
10. Sammelson, R. E.; Miller, R. B.; Kurth, M. J. J. Org.
Chem. 2000, 65, 2225.
11. For literature example of O-alkylation, oxime formation,
and 1,3-dipolar cycloaddition experimental procedure and
characterization see: Sammelson, R. E.; Gurusinghe, C. D.;
Kurth, J. M.; Olmstead, M. M.; Kurth, M. J. J. Org. Chem.
2002, 67, 876.
Figure 4. 3-(2-Benzyloxyphenyl)isoxazoles and 3-(2-benzyloxyphenyl)-
isoxazolines; activity of compounds on CFTR is reported in terms of
half effective concentration (Kd, in mM), Vmax (maximal IÀ influx, in
mM/s), and% of genistein activity at 50 mM. Each Kd and Vmax value
is the mean of three or more experiments and standard deviations (not
shown for simplicity) were less than 10% of the corresponding mean
value.
15 with 27, and consider the very low activity of 26). The
substituents in the benzyloxy ring do not seem to con-
sistently affect the activity (bromine seems to be better
than methoxy in 10 vs 16; however, methoxy is better
than bromine in 9 vs 15). Finally, these compounds were
also tested against CFTR with the G551D mutation, but