5734
J.-A. Kang et al. / Bioorg. Med. Chem. Lett. 21 (2011) 5730–5734
CDCl3) d 8.62 (m, 2H, 7-H, 9-H), 7.15 (dd, 1H, J = 7.6, 4.8 Hz, 8-H), 6.30 (s, 1H,
References and notes
4-H), 4.73 (dd, 1H, J = 10.0, 7.6 Hz, 2-H), 4.12 (s, 3H, NCH3), 3.94 (s, 3H, OCH3),
3.80 (dd, 1H, J = 14.4, 10.0 Hz, 1-Ha), 3.64 (dd, 1H, J = 14.4, 7.6 Hz, 1-Hb), 2.97
(d, 1H, J = 4.8 Hz, 30-Ha), 2.71 (d, 1H, J = 4.8 Hz, 30-Hb), 1.42 (s, 3H, 10-H); 13C
1. Peres, V.; Nagem, T. J.; de Oliveira, F. F. Phytochemistry 2000, 55, 683.
2. Kupchan, S. M.; Streelman, D. R.; Sneden, A. T. J. Nat. Prod. 1980, 43, 296.
3. Cassady, J. M.; Baird, W. M.; Chang, C.-J. J. Nat. Prod. 1990, 53, 23.
4. Svoboda, G. H. Lloydia 1966, 29, 206.
5. Dorr, R. T.; Liddil, J. D.; Von Hoff, D. D.; Soble, M.; Osborne, C. K. Cancer Res.
1989, 49, 340.
6. Costes, N.; Le Deit, H.; Michel, S.; Tillequin, F.; Koch, M.; Pfeiffer, B.; Renard, P.;
Leonce, S.; Guilbaud, N.; Kraus-Berthier, L.; Pierre, A.; Atassi, G. J. Med. Chem.
2000, 43, 2395.
7. Brum-Bousquet, M.; Mitaku, S.; Skaltsounis, A.-L.; Tillequin, F.; Koch, M. Planta
Med. 1988, 54, 470.
NMR (100 MHz, CDCl3)
d 177.46, 165.88, 164.22, 152.15, 151.84, 144.66,
136.60, 119.27, 117.80, 109.82, 102.22, 89.48, 84.90, 57.78, 56.56, 51.24, 35.58,
35.23, 17.17; HRMS (FAB+) calcd for C19H19N2O4 (M+H)+: 339.1345, found:
339.1351.
18. (2R⁄)-5-Methoxy-11-methyl-2-((2S⁄)-2-methyloxiran-2-yl)-1,2-
dihydrobenzofuro[4,5-b][1,8]naphthyridin-6(11H)-one: 1H NMR (400 MHz,
CDCl3) d 8.61 (m, 2H, 7-H, 9-H), 7.15 (dd, 1H, J = 7.2, 4.8 Hz, 8-H), 6.30 (s, 1H,
4-H), 4.70 (dd, 1H, J = 9.6, 7.6 Hz, 2-H), 4.11 (s, 3H, NCH3), 3.93 (s, 3H, OCH3),
3.80 (dd, 1H, J = 14.8, 9.6 Hz, 1-Ha), 3.62 (dd, 1H, J = 14.8, 7.6 Hz, 1-Hb), 2.84 (d,
1H, J = 4.4 Hz, 30-Ha), 2.74 (d, 1H, J = 4.4 Hz, 30-Hb), 1.42 (s, 3H, 10-H); 13C NMR
(100 MHz, CDCl3) d 177.47, 165.58, 164.17, 152.17, 151.81, 144.68, 136.58,
119.24, 117.91, 109.82, 102.56, 89.47, 85.00, 56.90, 56.56, 52.71, 35.59, 34.65,
16.81; HRMS (FAB+) calcd for C19H19N2O4 (M+H)+: 339.1345, found: 339.1336.
19. Cell culture and cytotoxicity test. The human cancer cell lines were purchased
from American Type Culture Collection (Rockville, MD) and maintained in a
humidified atmosphere at 37 °C in 5% CO2. The cells was grown in RPMI-1640
(Gibco, Rockville, MD) media containing 10% heat-inactivated fetal bovine
serum (FBS), 1.25 mM HEPES and 1% penicillin/streptomycin. Cytotoxicity was
determined by the MTT (Promega, Madison, WI) assay according to the
manufacturer’s protocol. Briefly, cells were seeded in 96-well microtiter plates
at a density of 2 ꢀ 103 cells per well. After 48 h incubation, cells were treated
with various concentrations of rac-1 and rac-2, cultured for for 24 and 48 h,
8. Kwok, Y.; Zeng, Q.; Hurley, L. H. Proc. Natl. Acad. Sci. U.S.A. 1998, 95, 13531.
9. David-Cordonnier, M.-H.; Laine, W.; Lansiaux, A.; Kouach, M.; Briand, G.; Pierre,
A.; Hickman, J. A.; Bailly, C. Biochemistry 2002, 41, 9911.
10. Yang, Z.; Kang, J.-A.; Kim, W. H.; Park, A.-Y.; Kim, H. S.; Kim, J.; Kim, J.-A.; Gong,
P.; Jeong, L. S.; Moon, H. R. Bull. Korean Chem. Soc. 2009, 30, 1463.
11. Kim, M.-Y.; Na, Y.; Vankayalapati, H.; Gleason-Guzman, M.; Hurley, L. H. J. Med.
Chem. 2003, 46, 2958.
12. 1H NMR (500 MHz, CDCl3) d 8.66–8.62 (m, 2H), 7.17 (dd, 1H, J = 4.5, 7.5 Hz),
6.35 (s, 1H), 5.24 (t, 1H, J = 9.0 Hz), 5.13 (s, 1H), 4.98 (s, 1H), 4.12 (s, 3H), 3.97 (s,
3H), 3.93 (dd, 1H, J = 9.5, 14.5 Hz), 3.55 (dd, 1H, J = 8.0, 14.5 Hz), 1.81 (s, 3H);
13C NMR (100 MHz, CDCl3) d 177.46, 166.11, 164.14, 152.10, 152.07, 143.38,
141.12, 136.57, 117.81, 113.78, 113.16, 109.64, 102.91, 89.49, 86.40, 56.53,
38.11, 35.62, 17.34.
respectively. At the end of the treatment period, 15
reagent was added to each well. After 4 h incubation at 37 °C, the supernatant
was aspirated, and formazan crystals were dissolved in 100 L DMSO at 37 °C
lL of the MTT (5 mg/mL)
13. 1H NMR (400 MHz, CDCl3) d 8.68 (dd, 1H, J = 2.0, 7.2 Hz), 7.77 (dd, 1H, J = 1.6,
6.4 Hz), 6.54 (t, 1H, J = 6.8 Hz), 6.24 (s, 1H), 5.28 (t, 1H, J = 8.8 Hz), 5.08 (s, 1H),
4.89 (s, 1H), 3.92 (s, 3H), 3.89 (s, 3H), 3.43 (dd, 1H, J = 10.0, 15.2 Hz), 3.41 (dd,
1H, J = 8.0, 15.2 Hz), 1.77 (s, 3H); 13C NMR (100 MHz, CDCl3) d 176.57, 164.70,
163.77, 150.99, 149.69, 144.38, 143.24, 143.19, 141.49, 123.62, 112.04, 111.37,
108.45, 88.43, 87.74, 56.33, 40.52, 33.24, 17.43.
l
for 10 min with gentle agitation. The absorbance per well was measured at
540 nm with a VERS Amax Microplate Reader (Molecular Devices Corp.). Assay
was done in triplicate. The IC50 values were then determined for each drugs
from a plot of log (drug concentration) versus percentage of loss of viability.
20. Flow cytometry. Cancer cells were exposed to rac-1 and rac-2 for 48 h. Total
number of cells was collected, washed, and suspended in cold PBS. The cells
were fixed in chilled 75% methanol and stained with propidium iodine (PI)
14. Reisch, J.; Mester, I.; El-Moghazy Aly, S. M. J. Chem. Soc., Perkin Trans. 1 1983,
219.
15. Fellows, I. M.; Schwaebe, M.; Dexheimer, T. S.; Vankayalapati, H.; Gleason-
Guzman, M.; Whitten, J. P.; Hurley, L. H. Mol. Cancer Ther. 2005, 4, 1729.
16. Habib, A. M.; Ho, D. K.; Masuda, S.; McCloud, T.; Reddy, K. S.; Aboushoer, M.;
McKenzie, A.; Byrn, S. R.; Chang, C.-J.; Cassady, J. M. J. Org. Chem. 1987, 52, 412.
17. (2R⁄)-5-Methoxy-11-methyl-2-((2R⁄)-2-methyloxiran-2-yl)-1,2-
dihydrobenzofuro[4,5-b][1,8]naphthyridin-6(11H)-one: 1H NMR (400 MHz,
solution (100 lg/mL RNase and 10 lg/mL PI in PBS). Data acquisition and
analysis was performed using a flow cytometry system (Becton Dickinson, San
Jose, CA).