Journal of Medicinal Chemistry
Brief Article
given in Hz. Reagents and solvents were purchased from common
commercial suppliers and were used as received. All starting materials
were commercially available unless otherwise indicated.
(9) ECDC/EMEA Joint Working Group. The Bacterial Challenge:
(10) Klevens, R. M.; Morrison, M. A.; Nadle, J.; Petit, S.; Gershman,
K.; Ray, S.; Harrison, L. H.; Lynfield, R.; Dumyati, G.; Townes, J. M.;
Craig, A. S.; Zell, E. R.; Fosheim, G. E.; McDougal, L. K.; Carey, R. B.;
Fridkin, S. K. Invasive methicillin-resistant Staphylococcus aureus
infections in the United States. JAMA, J. Am. Med. Assoc. 2007, 298,
1763−1771.
3-(4-Chlorophenyl)-1-(4-nitrophenyl)-1,4-dihydropyrazolo-
[4,3-c][1,2]benzothiazine 5,5-Dioxide (3g). To a suspension of 2
(4.00 g, 11.92 mmol) in 35 mL of absolute EtOH, a solution of (4-
nitrophenyl)hydrazine hydrochloride (4.52 g, 23.84 mmol) in 35 mL
of absolute EtOH was added dropwise. Then 5 mL of concentrated
H2SO4 was added to the mixture and refluxed for 48 h. The solvent was
evaporated and the solid crushed with 30 mL of a solution of EtOH:H2O
(50:50). After column chromatography eluting with CH2Cl2:MeOH
(99:1), compound 3g (3.20 g) was obtained as an orange solid (yield
(11) Centers for Disease Control and Prevention. Public Health
Dispatch: Vancomycin-Resistant Staphylococcus aureusPennsylvania,
2002. Morbidity Mortality Wkly. Rep., 2002, 51, 902.
1
59%, mp 283.7−284.9 °C). H NMR (DMSO-d6): δ 7.25 (d, J = 6.68
Hz, 1H), 7.64−7.73 (m, 4H), 7.92−7.97 (m, 2H), 8.04−8.11 (m, 3H),
8.48 (d, J = 9.07 Hz, 2H). Anal. (C21H13ClN4O4S) C, H, N.
(12) Patel, D.; Kosmidis, C.; Seo, S. M.; Kaatz, G. W. Ethidium
bromide MIC screening for enhanced efflux pump gene expression or
efflux activity in Staphylococcus aureus. Antimicrob. Agents Chemother.
2010, 54, 5070−5073.
(13) Pao, S. S.; Paulsen, I. T.; Saier, M. H. Jr. Major facilitator
superfamily. Microbiol. Mol. Biol. Rev. 1998, 62, 1−34.
(14) Yoshida, H.; Bogaki, M.; Nakamura, S.; Ubukata, K.; Konno, M.
Nucleotide sequence and characterization of the Staphylococcus aureus
norA gene, which confers resistance to quinolones. J. Bacteriol. 1990,
172, 6942−6949.
(15) Neyfakh, A. A. Mystery of multidrug transporters: the answer
can be simple. Mol. Microbiol. 2002, 44, 1123−1130.
(16) Zhang, L.; Ma, S. Efflux pump inhibitors: a strategy to combat
P-glycoprotein and the NorA multidrug resistance pump. Chem-
MedChem 2010, 5, 811−822.
(17) Brincat, J. P.; Carosati, E.; Sabatini, S.; Manfroni, G.; Fravolini,
A.; Raygada, J. L.; Patel, D.; Kaatz, G. W.; Cruciani, G. Discovery of
Novel Inhibitors of the NorA Multidrug Transporter of Staphylococcus
aureus. J. Med. Chem. 2011, 54, 354−365.
(18) Sabatini, S.; Gosetto, F.; Manfroni, G.; Tabarrini, O.; Kaatz, G.;
Patel, D.; Cecchetti, V. Evolution from a natural flavones nucleus to
obtain 2-(4-propoxyphenyl)quinoline derivatives as potent inhibitors
of the S. aureus NorA efflux pump. J. Med. Chem. 2011, 54, 5722−
5736.
ASSOCIATED CONTENT
* Supporting Information
■
S
Full experimental procedures, analytical data for compounds 1,
2, 3a−f, 3h, 3i and 4a−g, 4i, computational methods, NorA
predicted activity and biological data for the molecules screened
in silico, bacterial strains, microbiologic procedures and
cytotoxicity test method. This material is available free of
AUTHOR INFORMATION
Corresponding Author
■
*Phone: +39 075 5855130. Fax: +39 075 5855115. E-mail:
Notes
The authors declare no competing financial interest.
ACKNOWLEDGMENTS
We thank Dr. F. Modarelli for helpful discussions and
R. Bianconi and C. Moriconi for their technical support.
■
(19) Wright, G. D. Resisting resistance: new chemical strategies for
battling superbugs. Chem. Biol. 2000, 7, R127−R132.
(20) Kalle, A. M.; Rizvi, A. Inhibition of bacterial multidrug resistance
by celecoxib, a cyclooxygenase-2 inhibitor. Antimicrob. Agents Chemo-
ther. 2011, 55, 439−442.
(21) Baroni, M.; Cruciani, G.; Sciabola, S.; Perruccio, F.; Mason, J. S.
A common reference framework for analyzing/comparing proteins and
ligands. Fingerprints for Ligands and Proteins (FLAP): theory and
application. J. Chem. Inf. Model 2007, 47, 279−294.
(22) Kaatz, G. W.; Seo, S. M. Mechanisms of fluoroquinolone
resistance in genetically related strains of Staphylococcus aureus.
Antimicrob. Agents Chemother. 1997, 41, 2733−2737.
(23) Eliopoulos, G. M.; Moellering, R. C. J. Antimicrobial
combinations. In Antibiotics in Laboratory Medicine; Lorian, V., Ed.;
Williams and Wilkins: Baltimore, MD, 1991; pp 432−492.
(24) Wang, Q.; Lucien, E.; Hashimoto, A.; Pais, G. C.; Nelson,
D. M.; Song, Y.; Thanassi, J. A.; Marlor, C. W.; Thoma, C. L.; Cheng,
J.; Podos, S. D.; Ou, Y.; Deshpande, M.; Pucci, M. J.; Buechter, D. D.;
Bradbury, B. J.; Wiles, J. A. Isothiazoloquinolones with enhanced
antistaphylococcal activities against multidrug-resistant strains: effects
of structural modifications at the 6-, 7-, and 8-positions. J. Med. Chem.
2007, 50, 199−210.
ABBREVIATIONS USED
■
EPI, efflux pump inhibitor; COX-2, cyclooxygenase-2; MDR,
multidrug resistance; MRSA, methicillin-resistant S. aureus;
HAI, healthcare-associated infection; MFS, major facilitator
superfamily; SAR, structure−activity relationship; MDR1 or
P-gp1, multidrug resistance protein 1; EtBr, ethidium bromide;
CPX, ciprofloxacin; FLAP, fingerprints for ligands and proteins
REFERENCES
■
(1) Prabhavathi, F. Antibacterial discovery and developmentthe
failure of success? Nature Biotechnol. 2006, 24, 1497−1503.
(2) Bush, K.; Miller, G. H. Bacterial enzymatic resistance: beta-
lactamases and aminoglycoside-modifying enzymes. Curr. Opin.
Microbiol. 1998, 1, 509−515.
(3) Ruiz, J. Mechanisms of resistance to quinolones: target
alterations, decreased accumulation and DNA gyrase protection.
J. Antimicrob. Chemother. 2003, 51, 1109−1117.
(4) Nikaido, H. Molecular basis of bacterial outer membrane
permeability revisited. Microbiol. Mol. Biol. Rev. 2003, 67, 593−656.
(5) Li, X. Z.; Nikaido, H. Efflux-mediated drug resistance in bacteria:
an update. Drugs 2009, 69, 1555−1623.
(6) Kohler, T.; Pechere, J. C.; Plesiat, P. Bacterial antibiotic efflux
systems of medical importance. Cell. Mol. Life Sci. 1999, 56, 771−778.
(7) Mahamoud, A.; Chevalier, J.; Alibert-Franco, S.; Kern, W. V.;
Pages, J. M. Antibiotic efflux pumps in Gram-negative bacteria: the
inhibitor response strategy. J. Antimicrob. Chemother. 2007, 59, 1223−
1229.
(8) Poole, K.; Lomovskaya, O. Can efflux inhibitors really counter
resistance? Drug Discovery Today: Ther. Strategies 2006, 3, 145−152.
3572
dx.doi.org/10.1021/jm201446h | J. Med. Chem. 2012, 55, 3568−3572