H. T. Nguyen Thi et al. / Bioorg. Med. Chem. 16 (2008) 6737–6746
6745
2H), 7.44 (d, J = 10.3, 1H), 7.98 (d, J = 8.9, 1H), 8.07 (d, J = 9.0, 1H),
8.17 (s, 1H). MS (ESI, MeOH) m/z [M+] 433.2.
Bio, France), a primary antibody against a human PrP fragment
(amino acids 142–160), followed by an alkaline phosphatase-con-
jugated secondary antibody (anti-mouse IgG H&L, 1:20,000; Pro-
mega). Immunoreactive signals were visualized with CDP-Star
detection reagent (Amersham) and were analyzed densitometric-
ally with the ImageJ program (National Institute of Health, Bethes-
da, USA). Three independent assays were performed for each
concentration of test compound.
6.1.10. 6-Chloro-2-methoxy-N-(4-(4-methylpiperazin-1-
yl)phenyl)acridin-9-amine (15)
6,9-Dichloro-2-methoxyacridine and 4-(4-methylpiperazin-1-
yl)aniline (obtained from reduction of 1-methyl-4-(4-nitro-
phenyl)piperazine) were reacted in ethanol to give 15 as a yellow
solid in 65% yield. Mp 190.9–192.2 °C. 1H NMR (CDCl3) d 2.33 (s,
3H), 2.56 (t, J = 4.8, 4H), 3.12 (t, J = 4.6, 4H), 3.66 (s, 3H), 6.82 (b,
4H), 7.08 (s, 1H), 7.15 (d, J = 9.1, 1H), 7.32 (d, J = 9.4, 1H), 7.85 (d,
J = 9.2, 1H), 7.94 (d, J = 9.0, 1H), 8.02 (s, 1H). MS (ESI, MeOH) m/z
[M+] 431.9.
6.3. Statistical analysis
EC50 and its 95% confidence intervals were obtained by nonlin-
ear regression using the sigmoidal dose–response equation from
GraphPad Prism 4.03.
6.1.11. 6-Chloro-2-methoxyacridin-9-amine dihydrochloride (19)
6,9-Dichloro-2-methoxyacridine (0.028 g, 0.1 mol) was dis-
solved in 200 ml of methanol and refluxed for 2 h with a solution
of sodium methoxide, prepared by dissolving sodium (0.003 g,
0.12 mol) in 50 ml of methanol. The precipitated sodium chloride
was removed by filtration and the filtrate treated with water to
precipitate the desired product. 1H NMR (300 MHz, CDCl3) d 4.01
(s, 3H) 4.21 (s, 3H) 7.38 (d, J = 2.7, 1H) 7.47 (m, 2H) 8.09 (d,
J = 9.5, 1H) 8.19 (m, 2H). The product, 6-chloro-2,9-dimethoxyacri-
dine, was dissolved in 20 ml of alcohol and treated with ammo-
nium chloride (0.64 g, 0.12 mol) dissolved in 2 ml of water. The
mixture was maintained at 60–70 °C for 2 h. Compound 19 was ob-
tained as a yellow solid by filtration. (85% yield). Mp 341 °C. 1H
NMR (300 MHz, CD3OH) d 8.71–7.20 (m, 6H), 3.96 (s, 3H). MS
(ESI, MeOH) m/z [M]+ 258.1.
Acknowledgments
This work was supported by National University of Singapore
Academic Research Fund R148000064112 to GML and OWY, and
Japanese Ministry of Health, Labor and Welfare Research Grant
H19-nanji-006 to KD. Nguyen Thi Hanh Thuy gratefully acknowl-
edged financial support (Research Scholarship) from Ministry of
Education, Republic of Singapore and National University of Singa-
pore for her graduate studies. We thank Fumi Toshioka and Keiko
Nishizawa for technical assistances.
Supplementary data
Experimental procedures and analytical data for compounds 2–
5, 9, 18, 6, 7, 10–13, 16. Determination of purity of final compounds
5–8, 10–20 by HPLC. Supplementary data associated with this arti-
6.1.12. N1-(Acridin-9-yl)-N4,N4-diethylbenzene-1,4-diamine (20)
6,9-Dichloro-2-methoxyacridine and N1,N1-diethylbenzene-
1,4-diamine were reacted in ethanol as described in the general
procedure. Product was obtained as a brownish red solid in 88%
yield. Mp 227–228 °C. 1H NMR (CDCl3) d 1.09 (t, J = 6 Hz, 6H)
3.25 (q, J = 6 Hz, 4H) 6.56 (d, J = 9 Hz, 2H) 6.84 (d, J = 9 Hz, 2H)
7.21–7.16 (m, 2H) 7.57 (t, J = 9 Hz, 2H) 7.94 (t, J = 9 Hz, 4H). MS
(ESI, MeOH) m/z [M+] 341.2.
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l
l
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