Studies on anthracenes. 3. Synthesis, lipid peroxidation and cytotoxic evaluation of 10-substituted 1,5-dichloro-9(10H)-anthracenone derivatives

Article abstract of DOI:10.1248/cpb.49.1288

The synthesis of a series of 1,5-dichloro-9(10H)-anthracenones bearing O-linked and N-linked substituents in the 10-position are described. Previous studies have shown that 9-acyloxy 1,5-dichloroanthracenes and 9-acyloxy 1,8-dichloroanthracenes displayed

Full text of DOI:10.1248/cpb.49.1288

1288
Chem. Pharm. Bull. 49(10) 1288—1291 (2001)
Vol. 49, No. 10
Studies on Anthracenes. 3. Synthesis, Lipid Peroxidation and Cytotoxic
Evaluation of 10-Substituted 1,5-Dichloro-9(10H)-anthracenone
Derivatives
Hsu-Shan HUANG, ,a Pen-Yuan LIN,c Jing-Min HWANG,b Chi-Wei TAO,d Hsien-Chin HSU,a and
*
a
Yu-Liang LAI
School of Pharmacya and Department of Radiation Oncology,b National Defense Medical Center, Taipei Medical
University, School of Pharmacy,c and Cheng-Hsin Medical Center,d Taipei, Taiwan, R.O.C.
Received April 18, 2001; accepted June 6, 2001
The synthesis of a series of 1,5-dichloro-9(10H)-anthracenones bearing O-linked and N-linked substituents
in the 10-position are described. Previous studies have shown that 9-acyloxy 1,5-dichloroanthracenes and 9-acy-
loxy 1,8-dichloroanthracenes displayed a potential cytotoxic effect. These results have encouraged us in further
investigation of potential anthracenone derivatives. Therefore, a series of 10-substituted 1,8-dichloro-9(10H)-an-
thracenone derivatives were synthesized. These compounds were evaluated for their ability to inhibit the growth
of human oral epidermoid carcinoma cells (KB cell line), human cervical carcinoma cells of ME 180 (GBM 8401)
and Chinese hamster ovary (CHO) cells, respectively. Compounds 3c and 4c of this series compare favorably in
the KB cellular assay with mitoxantrone. Compound 4c showed combined inhibitory action against KB, GBM
and CHO cell growth, respectively. In addition, redox property of the compounds for the inhibition of lipid per-
oxidation in model membranes was determined. Compounds 4b and 4d exhibited stronger antioxidant activity
than ascorbic acid, (؉)-a-tocopherol and mitoxantrone, respectively.
Key words anthracenone; anthracene; cytotoxic; lipid peroxidation; bromination; nucleophilic substitution
Anthracenone derivatives display potent and selective anti- address these aspects of cancer. To gain a wider understand-
tumor activity, but their mechanism of action is not yet ing of the involvement of radicals in the action of anthra-
clearly established. Despite structural similarities between cenone-derived agents, several related compounds bearing
the substituents, anthracenone nucleus, and molecules pos- selected characteristic functional groups were designed. The
sessing known antitumor, antiproliferative, antipsoriatic, anti- approach was to develop structure–activity relationships
inflammatory, or antioxidant activity, these agents form a dis- (SARs) of 9(10H)-anthracenone analogs, with redox-active
tinct mechanistic class.1—3) Anthracene and anthracenone de- centers attached to the anthraquinone skeleton through
rivatives have been the subject of extensive research, mainly spacer side chains at position 10, together with substituents
due to their well-recognized biological importance and sig- with DNA-binding affinity. This paper describes the design
nificant biological applications. Although potential drug tar- and synthesis of anthracenones that incorporate in their
gets present only in cancerous cells have surfaced, the de- structure a potential antioxidant component, as well as the re-
sign of a drug which is selectively toxic to a tumor and not to sults of relevant biologic studies.
the host organism is still very difficult.4) We have previously
Chemistry The introduction of side chains onto the an-
shown that 9-acyloxy 1,5-dichloroanthracenes5) and 9-acy- thracenone nucleus is usually accomplished by a stepwise
loxy 1,8-dichloroanthracenes6) provide useful templates for procedure via the anthracenedione, because of the chemical
the design of potent antitumor derivatives. In previous pa- instability of many anthracenones. Therefore, the reduction
pers, we described the synthesis, biological evaluation and of 1,5-dichloroanthraquinone and bromination are required
structure–activity relationships for 9-acyloxy derivatives. In in the synthesis of C-10-substituted anthracenones. Although
order to provide further insight into anthracene and the an- several excellent methods are available for the reduction of
thracenone pharmacophore, including the involvement of anthracenediones, many reducing systems do not lead di-
free radicals and antiproliferative activity, we examined the rectly to the anthracene stage.8—10) The traditionally em-
effects of introducing electron-donating 10-oxy and 10-N ployed methods that lead preferentially to the anthracenones
substituents to determine where replacement of the electron- include stannous chloride in acetic acid/hydrochloric
withdrawing carbonyl of the earlier series can provide acid.11,12) Thus, treatment of 5 with bromine provides 6.
analogs with both potent antioxidant and antiproliferative ac- Bromination of anthracenone takes place at the 10-position.
tivities. Despite the extensive and long-standing therapeutic The structure of compound 6 was confirmed by X-ray analy-
utilization of anthracenones, their mechanism of action is sis. The ORTEP plot of 6 is shown in Fig. 2; the bond lengths
still uncertain. A large body of evidence is consistent with a and bond angles for this structure are listed in the experimen-
fundamental role of oxygen radicals in the induction of skin tal section. A series of 10-substituted 1,8-dichloro-9(10H)-
inflammation by anthracenes.7) The mode of action of anthra- anthracenones were synthesized from 6 by nucleophilic sub-
cenones leads to the conclusion that no single mechanism is stitution at C-10 with 1.5—2.0 equivalents of appropriate
predominantly operative, and oxygen radicals play a crucial amines or alcohols in the presence of catalytic amounts of
role in the proinflammatory action. As noted above, cancer is CaCO3, which strongly reduced the reaction time as com-
typically characterized by a hyperproliferative component. pared to the noncatalyzed reaction. The 10-oxy-substituted
There is thus a continuing need for effective compounds that and 10-N-substituted 1,8-dichloro-9(10H)-anthracenones
To whom correspondence should be addressed. e-mail: huanghs@ndmctsgh.edu.tw
© 2001 Pharmaceutical Society of Japan

October 2001
1289
Table 1. In Vitro Cytotoxicity Activity of 10-Substituted 1,5-Dichloro-
9(10H)-anthracenones
IC50 (mM)a)
Compound
X–R
GBMb)
KBc)
CHOd)
3a
3b
3c
3d
3e
3f
3g
4a
OCH3
OCH2CH3
23.5
21.8
11.1
65.4
29.5
43.2
18.5
7.5
8.8
6.1
1.8
21.8
29.5
14.7
93.4
17.2
9.5
2.9
5.8
42.0
15.2
8.0
20.1
24.7
15.0
6.2
OCH2CH2CH3
OCH(CH3)2
OCH2CH2CH2CH3
OCH2CH(CH3)2
OCH2C6H5
Fig. 1
N(CH2CH3)2
4b
4c
4d
NH(C6H4)CH3(m)
NH(C6H4)CH3(o)
NH(C6H4)CH3(p)
11.2
2.4
4.6
3.4
11.3
1.7
3.8
3.0
4.0
Mitoxantrone–HCl
1.5
a) The cytotoxicity tests were replicated 2 times. Each treatment has 3 replications.
IC50, drug concentration inhibiting 50% of cellular growth following 48 h of drug expo-
sure. b) Human cervical carcinoma cells of ME 180 (GBM8401). c) Human oral
epidermoid carcinoma cells (KB cell line). d) Chinese hamster ovary (CHO) cells.
over time as compared to control plates. The results are
shown in Table 1. Our study on the cytotoxicity evaluation of
10-substituted 1,8-dichloro-9(10H)-anthracenone derivatives
revealed that compounds 4a, 4c and 4d exhibited high cyto-
toxicity and significant activity on the GBM in vitro assay;
compounds 3c, 4b and 4c exhibited high cytotoxicity and
significant activity on the KB in vitro assay. Only compounds
3a, 4c and 4d were more toxic in CHO than mitoxantrone.
Although there were no obvious requirements for potent an-
tiproliferative activity, the inhibitory effects of these com-
pounds appear to be due to some selective cell lines rather
than to nonspecific redox properties. In addition to the redox
properties, other factors such as an appropriate geometry of
the molecules when bound to the active site of the substrate
may be responsible for the cell growth inhibitory activities of
the novel anthracenone and anthracene analogs.
The inhibitory effect on lipid peroxidation of these com-
pounds was evaluated using rat brain phospholipid liposomes
which provide an ideal model system for lipid peroxidation
studies.15) When compared to ascorbic acid, (ϩ)-a-toco-
pherol and mitoxantrone, we found a better inhibitory effect
at 0.5 mM by compounds 4b and 4d (Table 2). Furthermore,
compounds 4b and 4d were significantly more efficient than
ascorbic acid, (ϩ)-a-tocopherol or mitoxantrone at 0.005 mM
(Table 3). Although not a potent inhibitor of lipid peroxida-
tion in itself, can provide a useful template for the design of
potential anticancer agents. Moreover, the results support our
hypothesis that structural modification of 1,5-dichloro-
9(10H)-anthracenone may lead to control of the release of
Fig. 2
(a): Br2, CS2; (b) CaCO3, THF, N2, R-OH or R-NH2. R is defined in Table 1.
Chart 1
were readily synthesized according to Chart 1. The structures
of these compounds were established on the basis of spectro-
scopic analysis. The 1H-NMR spectra of 6 show a singlet at d
6.62 for the C-10 of H, a doublet at d 8.11 for the proton at
position 8 and a dd at d 7.65 for the proton at position 6. Of
particular importance in these series compounds are the one
proton chemical shifts at position 10 between d 5.31 and
6.08, which are different from the range of the 5 possessing
two 10-H protons at d 4.32, and the IR stretching frequency,
which is indicative of a CϭO stretch. Furthermore, the 13C-
NMR spectra of these compounds show the usual carbonyl
absorbance signal in the d 180—190 region.13,14)
Results and Discussion
In previous papers, we described the synthesis and some active oxygen species. In light of these findings, it is sug-
biological evaluation of 9-acyloxy 1,5-dichloroanthracenes gested that cytoyoxicity activity and lipid peroxidation alone
and 9-acyloxy 1,8-dichloro anthracenes, respectively. In gen- is not sufficient for potent antiproliferative action. Whatever
eral, results from these assays did not show a reasonable cor- the molecular mechanism of the antiproliferative action of
relation. We evaluated the ability of the compounds to inhibit anthracenones, and wherever its locus, the results described
the growth of human oral epidermoid carcinoma cells (KB herein indicate that it is sensitive to the slightest modification
cell line), human cervical carcinoma cells of ME 180 in the structure of anthracenone and that active analogs can
(GBM8401) and Chinese hamster ovary (CHO) cells as nor- be made only if the anthracenone moiety itself is retained. In
mal cells, as well as lipid peroxidation in model membranes, conclusion, we have presented 10-substituted 1,8-dichloro-
respectively. The compounds were tested by a cytotoxic ac- 9(10H)-anthracenone derivatives which show potent inhibi-
tivity assay as demonstrated by the reduction in cell number tion of some selective cell lines. In order to understand

1290
Vol. 49, No. 10
Cell constants aϭ7.6092(13), bϭ8.5639(14), and cϭ10.0242(14) Å;
aϭ76.212(11)°; bϭ73.058(12)°; gϭ87.135(12)°; Vϭ606.7(2) Å3; Zϭ2;
m(MoKa)ϭ3.809 cmϪ1; F(000)ϭ336. Cell dimensions were determined
using a Nonious CAD4 Kappa Axis XRD & Siemens Smart CCD XRD dif-
fractometer equipped with a graphite monochromator and molybdenum
source (lϭ7.1073 Å). Data were collected on the same instrument using w
scans with 2q varying from 2—50°. A total of 3090 unique reflections were
determined, of which 1647 were Ͼ2.0s. The structure was solved using di-
rect methods and was refined using standard techniques. A total of 235 para-
meters were varied in the final least-squares. The refinement converged at
Rϭ0.040 and Rwϭ0.040. Residual electron density varied from 0.20 to
Ϫ0.20 e/Å3.
General Procedure for the Preparation of 10-Substituted 1,5-
Dichloro-9(10H)-anthracenones To a solution of 6 (2.0 mmol) and anhy-
drous calcium carbonate (0.5 g) in dry THF (20 ml) was added dropwise a
solution of an appropriate alcohol or amine (3 mmol) in dry THF (10 ml)
under N2. The reaction mixture was stirred at room temperature or refluxed
for several hours. Water (250 ml) was added and then extracted with
dichloromethane. The combined organic extracts were washed with water,
dried (MgSO4), and concentrated. The resulting precipitate was collected by
filtration, washed with water and further purified by crystallization and chro-
matography.
Table 2. Inhibitory Effect of 10-Substituted 1,5-Dichloro-9(10H)-anthra-
cenones of the Invention on Iron-induced Lipid Peroxidation in Rat Brain
Homogenates
Compound
X
R
Inhibition % (0.5 mM)a)
3a
3b
3c
3d
3e
3f
3g
4a
O
O
O
O
O
O
O
N
CH3
CH2CH3
7Ϯ0.1
7Ϯ0.1
29Ϯ2.5
13Ϯ1.3
31Ϯ3.7
38Ϯ3.1
16Ϯ1.5
12Ϯ1.4
100
CH2CH2CH3
CH(CH3)2
CH2CH2CH2CH3
CH2CH(CH3)2
CH2C6H5
(CH2CH3)2
4b
4c
4d
NH
NH
NH
(C6H4)CH3(m)
(C6H4)CH3(o)
(C6H4)CH3(p)
73Ϯ3.5
100
Ascorbic acid
(ϩ)-a-Tocopherol
Mitoxantrone–HCl
87Ϯ3.1
53Ϯ4.4
64Ϯ2.8
a) Relative percentage of inhibition. Inhibition was compared to that of the control
[ascorbic acid, (ϩ)-a-tocopherol and mitoxantrone–HCl], pϽ0.01, meanϮS.E., nϭ4.
Values are the mean percent inhibition at the indicated concentration (mM), and stan-
dard errors.
10-Methoxy 1,5-Dichloro-9(10H)-anthracenone (3a): 90% yield. mp
1
170—171 °C. H-NMR (CDCl3) d: 8.04 (1H, dd, Jϭ0.9, 7.6 Hz), 7.63 (1H,
dd, Jϭ1.0, 7.4 Hz), 7.55 (1H, dd, Jϭ2.3, 6.6 Hz), 7.52 (1H, d, Jϭ2.5 Hz),
7.51 (1H, t, Jϭ7.3 Hz), 7.45 (1H, t, Jϭ7.8 Hz), 5.76 (1H, s), 3.1 (3H, s). 13C-
NMR (CDCl3) d: 183.55, 141.99, 137.13, 135.76, 135.37, 134.94, 134.39,
133.60, 133.36, 130.65, 130.18, 129.28, 126.76, 72.52, 54.67. MS m/z: 292
(Mϩ), 261. IR (KBr) cmϪ1: 1670, 1068. UV lmax (CHCl3) nm (log e): 282
(4.72). Anal. Calcd for C15H10O2Cl2: C, 49.15; H, 3.44. Found: C, 49.41; H,
3.21.
Table 3. Inhibitory Effects of 4b and 4d on Iron-Induced Lipid Peroxida-
tion in Rat Brain Homogenates
Inhibition (%)a)
Compound
10-Ethoxy 1,5-Dichloro-9(10H)-anthracenone (3b): 95% yield. mp 153—
154 °C. H-NMR (CDCl3) d: 8.03 (1H, dd, Jϭ0.8, 7.6 Hz), 7.61 (1H, dd,
5 mM
0.5 mM
0.05 mM 0.005 mM
1
Jϭ0.8, 7.6 Hz), 7.54 (1H, dd, Jϭ2.1, 6.6 Hz), 7.51(1H, d, Jϭ5.7 Hz), 7.49
(1H, t, Jϭ7.7 Hz), 7.43 (1H, t, Jϭ7.8 Hz), 5.79 (1H, s), 3.32—3.25 (2H, m),
1.04 (3H, t, Jϭ6.9 Hz). 13C-NMR (CDCl3) d: 183.67, 142.67, 137.06,
136.35, 135.26, 134.85, 134.31, 133.52, 133.16, 130.47, 130.07, 129.17,
126.71, 71.66, 62.87, 15.76. MS m/z: 306 (Mϩ), 261. IR (KBr) cmϪ1: 1678,
1069. UV lmax (CHCl3) nm (log e): 280 (4.88). Anal. Calcd for C16H12O2Cl2:
C, 62.54; H, 3.94. Found: C, 62.18; H, 3.85.
10-Propyloxy 1,5-Dichloro-9(10H)-anthracenone (3c): 62% yield. mp
98—99 °C. 1H-NMR (CDCl3) d: 8.04 (1H, dd, Jϭ0.8, 7.6 Hz), 7.62 (1H, dd,
Jϭ0.9, 7.6 Hz), 7.55 (1H, dd, Jϭ2.2, 6.5 Hz), 7.52—7.48 (2H, m), 7.44 (1H,
t, Jϭ7.7, 7.9 Hz), 5.82 (1H, s), 3.14 (2H, t, Jϭ6.4 Hz), 1.44—1.37 (2H, m),
0.73 (3H, t, Jϭ7.2, 7.4 Hz). 13C-NMR (CDCl3) d: 183.65, 142.74, 137.08,
136.33, 135.22, 134.92, 134.35, 133.54, 133.14, 130.46, 130.09, 129.23,
71.60, 68.75, 23.45, 11.07. MS m/z: 320 (Mϩ), 261. IR (KBr) cmϪ1: 1678,
1051. UV lmax (CHCl3) nm (log e): 281 (4.66). Anal. Calcd for C17H14O2Cl2:
C, 63.55; H, 4.39. Found: C, 63.28; H, 4.23.
4b
4d
100
100
100
100
100
100
100
92Ϯ4.1 23Ϯ2.4
94Ϯ3.5 33Ϯ2.7
Ascorbic acid
(ϩ)-a-Tocopherol
Mitoxantrone–HCl
87Ϯ2.5 22Ϯ2.2
53Ϯ1.7
64Ϯ2.1 52Ϯ3.5 10Ϯ1.1
7Ϯ0.5
0
0
a) Relative percentage of inhibition. Inhibition was compared to that of the control
[ascorbic acid, (ϩ)-a-tocopherol and mitoxantrone–HCl], pϽ0.01, meanϮS.E., nϭ4.
Values are mean percent inhibition at the indicated concentration (mM), and standard
errors.
whether these compounds have potent antitumor and biologi-
cal activities, we will examine their effects in other tests and
the results will be reported elsewhere.
Experimental
10-(2-Propyloxy) 1,5-Dichloro-9(10H)-anthracenone (3d): 58% yield. mp
172—173 °C. H-NMR (CDCl3) d: 7.99 (1H, dd, Jϭ0.9, 7.6 Hz), 7.58 (1H,
1
All temperatures are reported in degrees centigrade. Melting points were
determined with a Büchi B-545 melting point apparatus and are uncorrected.
Chromatography refers to column chromatography using silica gel (E.
Merck, 70—230 mesh). 1H-NMR spectra were recorded with a Varian
GEMR-H-300 (300 MHz); d values are in ppm relative to a tetramethylsi-
lane internal standard. Fourier-transform IR spectra (KBr) were recorded on
a Perkin-Elmer 983G spectrometer. Mass spectra (EI, 70 eV, unless other-
wise stated) were obtained on a Finnigan MAT TSQ-46 and Finnigan MAT
TSQ-700. UV spectra were recorded on a Shimadzu UV-160.
dd, Jϭ1.0, 7.6 Hz), 7.50 (1H, dd, Jϭ2.6, 7.0 Hz), 7.48—7.44 (2H, m), 7.41
(1H, t, Jϭ7.8 Hz), 5.83 (1H, s), 3.6 (1H, m), 1.06—0.88 (6H, dd, Jϭ6.0,
6.1 Hz). 13C-NMR (CDCl3) d: 84.19, 143.29, 137.43, 137.22, 134.19,
134.42, 134.06, 133.23, 133.02, 130.39, 129.05, 126.84, 69.64, 68.81, 23.61,
22.80. MS m/z: 320 (Mϩ), 261. IR (KBr) cmϪ1: 1679, 1016. UV lmax
(CHCl3) nm (log e): 287 (4.77). Anal. Calcd for C17H14O2Cl2: C, 62.54; H,
3.94. Found: C, 62.32; H, 3.73.
10-(Butyloxy) 1,5-Dichloro-9(10H)-anthracenone (3e): 50% yield. mp
10-Bromo 1,5-Dichloro-9(10H)-anthracenone (6)11) To a solution of
1,5-dichloro-9(10H)-anthracenone5) (16.0 mmol) in CS2 (30 ml) was added
dropwise a solution of bromine (20.0 mmol) in CS2 (5 ml). The reaction
mixture was refluxed for 1 h. The reaction mixture was allowed to cool, fil-
tered, and the filtrate was evaporated to dryness. The remaining crude prod-
uct was dissolved in dichloromethane. The combined organic extracts were
washed with water and dried (MgSO4), and the solution was concentrated.
The resulting precipitate was collected by filtration, and further purified by
crystallization and chromatography to give the corresponding product: 95%
1
117—118 °C. H-NMR (CDCl3) d: 8.04 (1H, dd, Jϭ0.9, 7.7 Hz), 7.61 (1H,
dd, Jϭ1.0, 7.7 Hz), 7.55 (1H, dd, Jϭ2.2, 6.5 Hz), 7.52—7.48 (2H, m), 7.44
(1H, t, Jϭ7.8 Hz), 5.81 (1H, s), 3.18 (2H, t, Jϭ6.3 Hz), 1.36 (2H, m), 1.17
(2H, m), 0.72 (3H, t, Jϭ7.4 Hz). 13C-NMR (CDCl3) d: 183.66, 142.78,
137.12, 136.34, 135.24, 134.91, 134.33, 133.50, 133.13, 130.44, 130.13,
129.20, 126.67, 71.58, 66.63, 32.24, 19.66, 14.14. MS m/z: 334 (Mϩ), 261.
IR (KBr) cmϪ1: 1678, 1060. UV lmax (CHCl3) nm (log e): 280 (4.84). Anal.
Calcd for C18H16O2Cl2: C, 64.48; H, 4.81. Found: C, 64.21; H, 4.89.
10-(iso-Butyloxy) 1,5-Dichloro-9(10H)-anthracenone (3f): 65% yield. mp
1
1
yield. mp 201—202 °C. H-NMR (CDCl3) d: 8.11 (1H, d, Jϭ7.1 Hz), 7.65
146—147 °C. H-NMR (CDCl3) d: 8.04 (1H, dd, Jϭ0.8, 7.9 Hz), 7.62 (1H,
(1H, dd, Jϭ1.2, 8.0 Hz), 7.61—7.46 (4H, m), 6.62 (1H, s). MS m/z: 341
(Mϩ), 261. UV lmax (CHCl3) nm (log e): 295 (4.57). IR (KBr) cmϪ1: 1670.
X-Ray Crystal Structure of 6: C14H7BrCl2O, Mtϭ342.01. A needle of the
approximate dimensions 0.5ϫ0.4ϫ0.12 mm was mounted to glass fiber
along its longest axis. The crystal system was triclinic, space group P-1.
dd, Jϭ0.9, 7.6 Hz), 7.55 (1H, dd, Jϭ2.4, 6.3 Hz), 7.53 (1H, d, Jϭ6.1 Hz),
7.50 (1H, t, Jϭ6.5 Hz), 7.44 (1H, t, Jϭ7.8 Hz), 5.83 (1H, s), 2.92—2.87
(2H, m), 1.66—1.54 (1H, m), 0.70 (6H, t, Jϭ6.8, 6.7 Hz). 13C-NMR
(CDCl3) d: 183.62, 142.78, 137.07, 136.29, 135.18, 134.95, 134.36, 133.54,
133.11, 130.43, 130.09, 129.26, 126.61, 73.50, 71.52, 29.03, 19.84, 19.79.

October 2001
1291
MS m/z: 334 (Mϩ), 261. IR (KBr) cmϪ1: 1681, 1056. UV lmax (CHCl3) nm
(log e): 281 (4.55). Anal. Calcd for C18H16O2Cl2: C, 64.48; H, 4.81. Found:
C, 64.23; H, 4.75.
Cytotoxic Activity Test Human oral epidermoid carcinoma cells (KB
cell line), human cervical carcinoma cells of ME 180 (GBM8401) and Chi-
nese hamster ovary (CHO) cells grown in plateau phase were cultivated, and
the cell proliferation assay was performed as previously described.6) Inhibi-
tion of cellular growth was calculated by comparison of the mean values of
the test compound (nϭ3) with the control (nϭ6—8) activity: (1Ϫtest com-
pound/control)ϫ100.
Assay of Lipid Peroxidation Rat brain homogenate was prepared from
the brains of freshly killed Wistar rats, and its peroxidation in the presence
of iron ions was measured by the thiobarbituric acid (TBA) method as previ-
ously described.5,15) The extent of lipid peroxidation was estimated as thio-
barbituric acid-reactive substances and was read at 532 nm in a spectropho-
tometer (Shimadzu UV-160). The results of this assay are provided in Tables
2 and 3.
10-Benzyloxy 1,5-Dichloro-9(10H)-anthracenone (3g): 75% yield. mp
150—151 °C. 1H-NMR (CDCl3) d: 8.05 (1H, d, Jϭ7.6 Hz), 7.62 (1H, d,
Jϭ8.0 Hz), 7.57 (1H, d, Jϭ6.9 Hz), 7.55—7.51 (2H, m), 7.45 (1H, t,
Jϭ7.8 Hz), 7.23—7.14 (5H, m), 5.96 (1H, s), 4.27 (2H, dd, Jϭ6.5, 10.9 Hz).
13C-NMR (CDCl3) d: 183.56, 142.32, 137.96, 137.21, 136.09, 135.41,
134.91, 134.43, 133.64, 133.38, 130.69, 130.20, 129.38, 128.85, 128.43,
128.34, 126.83, 71.57, 69.29. MS m/z: 368 (Mϩ), 261. IR (KBr) cmϪ1: 1676,
1047. UV lmax (CHCl3) nm (log e): 280 (4.83). Anal. Calcd for C21H14O2Cl2:
C, 68.29; H, 3.82. Found: C, 68.18; H, 3.68.
10-Diethylamino 1,5-Dichloro-9(10H)-anthracenone (4a): 64% yield. mp
1
192—193 °C. H-NMR (CDCl3) d: 8.07 (1H, dd, Jϭ1.9, 7.7 Hz), 7.59 (1H,
dd, Jϭ1.0, 7.8 Hz), 7.47—7.31 (4H, m), 5.31 (1H, s), 2.59—2.20 (4H, m),
0.92 (6H, t, Jϭ7.0 Hz). 13C-NMR (CDCl3) d: 184.67, 142.83, 138.91,
138.00, 134.96, 134.25, 132.71, 131.96, 130.79, 129.30, 128.56, 125.91
58.04, 44.06, 14.13. MS m/z: 333 (Mϩ), 261. IR (KBr) cmϪ1: 1674, 1299.
UV lmax (CHCl3) nm (log e): 275 (4.97). Anal. Calcd for C18H17NOCl2: C,
64.67; H, 5.12. Found: C, 64.48; H, 5.35.
Acknowledgment This research was supported by grants from NDMC.
The authors are indebted to Dr. K. K. Mayer (University of Regensburg,
Germany) for the mass spectrometry analytical determination.
References
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Y., Lai Y. L., Chem. Pharm. Bull., 49, 1346—1348 (2001).
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(1996).
10-(m-Toluidino) 1,5-Dichloro-9(10H)-anthracenone (4b): 66% yield. mp
186—188 °C. H-NMR (CDCl3) d: 8.08 (1H, dd, Jϭ1.0, 7.7 Hz), 7.65 (1H,
1
dd, Jϭ1.2, 7.8 Hz), 7.50—7.33 (4H, m), 7.07 (1H, t, Jϭ7.8 Hz), 6.61 (1H,
s), 6.63 (1H, s), 6.56 (1H, s), 6.05 (1H, s), 3.72 (1H, s), 2.26 (3H, s). 13C-
NMR (CDCl3) d: 183.56, 146.28, 145.88, 139.73, 138.20, 136.22, 135.35,
134.71, 134.55, 133.92, 132.50, 129.87, 129.76, 128.41, 127.54, 126.85,
121.14, 117.38, 113.30, 52.63, 22.12. MS m/z: 367 (Mϩ), 261. IR (KBr)
cmϪ1: 3359, 1664. UV lmax (CHCl3) nm (log e): 272 (5.17). Anal. Calcd for
C21H15NOCl2: C, 68.48; H, 4.10. Found: C, 68.27; H, 4.35.
10-(o-Toluidino) 1,5-Dichloro-9(10H)-anthracenone (4c): 58% yield. mp
1
193—195 °C. H-NMR (CDCl3) d: 8.12 (1H, dd, Jϭ0.8, 8.4 Hz), 7.66 (1H,
dd, Jϭ1.3, 7.9 Hz), 7.50—7.26 (4H, m), 7.16 (1H, d, Jϭ4.1 Hz), 7.01 (1H, d,
Jϭ7.4 Hz), 6.77—6.72 (2H, m), 6.08 (1H, s), 3.68 (1H, s), 1.87 (3H, s). 13C-
NMR (CDCl3) d: 183.56, 146.02, 144.37, 138.31, 136.31, 135.39, 134.79,
134.63, 133.89, 132.52, 131.30, 129.96, 127.62, 127.34, 126.94, 125.21,
119.97, 114.76, 114.72, 52.89, 17.98. MS m/z: 367 (Mϩ), 261. IR (KBr)
cmϪ1: 3402, 1658. UV lmax (CHCl3) nm (log e): 276 (5.24). Anal. Calcd for
C21H15NOCl2: C, 68.48; H, 4.10. Found: C, 68.19; H, 4.26.
10-(p-Toluidino) 1,5-Dichloro-9(10H)-anthracenone (4d): 73% yield. mp
1
189—191 °C. H-NMR (CDCl3) d: 8.06 (1H, dd, Jϭ1.0, 7.8 Hz), 7.65 (1H,
dd, Jϭ1.2, 7.9 Hz), 7.46—7.40 (3H, m), 7.35 (1H, t, Jϭ7.2 Hz), 6.97 (2H, d,
Jϭ8.0 Hz), 6.65 (2H, d, Jϭ8.3 Hz), 5.97 (1H, s), 3.69 (1H, s), 2.23 (3H, s).
13C-NMR (CDCl3) d: 183.54, 145.79, 143.76, 138.25, 136.24, 135.33,
134.69, 134.47, 133.82, 132.46, 130.43, 129.92, 129.84, 128.47, 127.66,
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H. E., Phytochemistry, 16, 735 (1977).
14) Bhawal B. M., Khanapure S. P., Zhang H., Biehl E. R., J. Org. Chem.,
56, 2846—2849 (1991).
126.85, 117.24, 53.44, 21.07. MS m/z: 367 (Mϩ), 261. IR (KBr) cmϪ1
:
15) Teng C. M., Hsiao G., Ko F. N., Lin D. T., Lee S. S., Eur. J. Pharma-
col., 303, 129—139 (1996).
3381, 1658. UV lmax (CHCl3) nm (log e): 275 (5.09). Anal. Calcd for
C21H15NOCl2: C, 68.48; H, 4.10. Found: C, 68.56; H, 4.23.