Synthesis of (2E)-3-{2-[(substituted benzyl)oxy]phenyl}acrylaldehydes as novel anti-inflammatory agents

Article abstract of DOI:10.1016/j.bmcl.2006.02.005

As part of our continuing effort for development of novel anti-inflammatory agents, the highly potential agent CCY1a, which we reported recently, was selected as lead compound to synthesize a series of its derivatives for evaluation. Most of the newly synthesized compounds exhibited superior inhibitory activity than both the lead compound and the positive control (trifluoperazine) toward fMLP-stimulated neutrophil superoxide formation. (2E)-3-[2-(Benzyloxy)-5-methoxyphenyl]-acrylaldehyde (31) was among the most potent with action mechanism different from CCY1a in that it does not act as cAMP-elevating agent but inhibits the increase in cellular Ca²⁺ with greater potency.

Full text of DOI:10.1016/j.bmcl.2006.02.005

Bioorganic & Medicinal Chemistry Letters 16 (2006) 2742–2747
Synthesis of
(2E)-3-{2-[(substituted benzyl)oxy]phenyl}acrylaldehydes
as novel anti-inflammatory agents
a
a
Li-Jiau Huang,a,* Jih-Pyang Wang,a,b, Yu-Chi Lai and Sheng-Chu Kuo
*
aGraduate Institute of Pharmaceutical Chemistry, China Medical University, Taichung 40402, Taiwan, ROC
bDepartment of Education and Research, Taichung Veterans General Hospital, Taichung 407, Taiwan, ROC
Received 26 September 2005; revised 28 January 2006; accepted 6 February 2006
Available online 28 February 2006
Abstract—As part of our continuing effort for development of novel anti-inflammatory agents, the highly potential agent CCY1a,
which we reported recently, was selected as lead compound to synthesize a series of its derivatives for evaluation. Most of the newly
synthesized compounds exhibited superior inhibitory activity than both the lead compound and the positive control (trifluoperazine)
toward fMLP-stimulated neutrophil superoxide formation. (2E)-3-[2-(Benzyloxy)-5-methoxyphenyl]-acrylaldehyde (31) was among
the most potent with action mechanism different from CCY1a in that it does not act as cAMP-elevating agent but inhibits the
increase in cellular Ca2+ with greater potency.
Ó 2006 Elsevier Ltd. All rights reserved.
In our previous work,1 several regioisomers of benzyl-
oxybenzaldehyde were synthesized and determined to
have significant inhibitory activity toward neutrophil
superoxide anion generation. Among these compounds,
2-benzyloxybenzaldehyde (1, CCY1a) was the most
promising one, which was further identified as an indi-
rect adenylyl cyclase activator,2 through the release of
endogenous adenosine. The inhibition of superoxide
anion generation by CCY1a in neutrophils is attributed
partly to its cAMP-elevating activity, and partly to the
blockade of external Ca2+ entry and phospholipase D
activation via cAMP-independent mechanisms.2–4
when cinnamic aldehyde (2) was reacted with a variety
of substituted benzyl chlorides (3–14) and K2CO3 in
EtOH, the corresponding target compounds (15–26)
were obtained. On the other hand, as illustrated in
Scheme 2, 2-(substituted benzyloxy)-5-methoxybenzal-
dehyde (27–30),5 which was prepared from 2-hydroxy-
5-methoxybenzaldehyde and substituted benzyl chloride
(3–6), was treated with equal mole of acetaldehyde at
low temperature to undergo aldol condensation which
resulted in the formation of (2E)-3-[2-(substituted ben-
zyloxy)-5-methoxyphenyl]acrylaldehyde (31–34). Final-
ly, compounds 31–33 were treated with hydroxylamine
to afford the corresponding oximes 35–37. All the syn-
thetic compounds were characterized by their spectral
characteristics.6
In the present work, CCY1a was selected as lead com-
pound and
a
series of 3-{2-[(substituted ben-
zyl)oxy]phenyl}acrylaldehydes were synthesized and
their effect on neutrophil superoxide formation and
cAMP-elevating activity were evaluated.
Superoxide anion formation was measured in terms of
superoxide dismutase inhibitable cytochrome c reduc-
tion.7 Briefly, the assay mixture contained the cell sus-
pension and 0.5 mg/mL of cytochrome c (DA550), the
reference mixture also received 6.6 lg/mL of superoxide
dismutase. Reaction was initiated by stimulating with
0.3 lM formyl-Met-Leu-Phe (fMLP) or 3 nM phorbol
12-myristate 13-acetate (PMA).
The (2E)-3-{2-[(substituted benzyl)oxy]phenyl}acrylal-
dehydes (15–26) were synthesized according to the syn-
thetic method of CCY1a.1 As shown in Scheme 1,
Keywords: Anti-inflammatory agents; 3-{2-[(Substituted benzyl)-
oxy]phenyl}-acrylaldehydes.
According to the data in Table 1, converting the
–CHO moiety of lead compound (CCY1a) into
–CH@CH–CHO (15) improved its activity significant-
ly. Moreover, the addition of a Cl atom into the ortho
*
Corresponding authors. Tel.: +886 4 22053366 1007; fax: +886 04
22055105 (L.J.H.); tel.: +886 04 23592525 2043; fax: +886 04
23592705 (J.P.W.); e-mail addresses: ljhuang@mail.cmu.edu.tw;
w1994@vghtc.vghtc.gov.tw
0960-894X/$ - see front matter Ó 2006 Elsevier Ltd. All rights reserved.
doi:10.1016/j.bmcl.2006.02.005

L.-J. Huang et al. / Bioorg. Med. Chem. Lett. 16 (2006) 2742–2747
2743
Scheme 1. Reagents and conditions: (a) K2CO3, KI/ethanol, reflux.
Scheme 2. Reagents and conditions: (a) 20% NaOH/ethanol, 0 °C; (b) NH2OH ÆHCl, CH3COONa/ethanol, reflux.
position of the benzyl group in compound 15 resulted
in compound 16 with further improved activity.
Meanwhile, the placement of the same Cl atom in
the meta position (17) appeared to be functionless,
whereas a Cl atom in para position (18) resulted in re-
duced activity. In order approaches, it was found that
the substitution of the ortho Cl of compound 16, or
the meta Cl of 17 with F atom, resulted in compounds
19 and 20 with a slight improvement in their activity.
Then our attempt to modify compound 15 by adding
a CH3 group onto its para position at benzyl group
resulted in compound 21 with only about half the
activity.
In particular, the IC50 value for compound 31 was deter-
mined as 2.6 lM which is about 6 times more active than
the lead compound CCY1a or the positive control (tri-
fluoperazine). After introduction of a Cl atom onto
the benzyl group of compound 31 at either the ortho-
(32), meta-(33) or para-location (34), only the 3-chloro-
benzyl derivatives (33) maintain significant inhibitory
activity against superoxide formation. Our attempt in
derivatization of compound 31 into an oxime (35) result-
ed in 50% lower activity, whereas similar derivatization
of compound 32 resulted in compound 36 with im-
proved activity in 30 lM concentration. On the other
hand, all the compounds were tested for their inhibitory
activity against PMA-stimulated superoxide anion for-
mation. The result indicated that, unlike the positive
control TFP, none of the tested compounds showed sig-
nificant activity in the test concentration range 1–30 lM.
This seems to suggest that, the action mechanism of the
test compounds differs when tested against superoxide
anion generation by different stimulants.
Results on the effect of all dichlorobenzyl derivatives
(23–26) on neutrophil superoxide anion formation indi-
cated that only 3,4-dichlorobenzyl derivatives (23) dem-
onstrated significant activity. Neither its 2,3-dichloro
(24), 2,4-dichloro (25) nor 2,6-dichloro (26) isomers
show any significant activity. Excitingly, the incorpora-
tion of an OCH3 group into the 4 position at the benzyl-
oxy group (22) and the 5 position at the phenyl group
(31) of compound 15 resulted in significant boost of
activity.
Summarizing all the above findings, compound 31 was
found to demonstrate the greatest inhibitory activity
against fMLP-induced superoxide anion formation of

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L.-J. Huang et al. / Bioorg. Med. Chem. Lett. 16 (2006) 2742–2747
Table 1. The inhibitory effects of 15–26 and 31–37 on the neutrophil superoxide formation
Inducer: fMLP (0.3 μM)/cytochalasin B (5 μg/mL)
Inducer: PMA (3 nM)
Animal: Rat (Sprague Dawley)
Compound
R0
Concentration (lM)
Superoxide formation (nmol/106 cells/30 min)
fMLP
% inhibition
PMA
% inhibition
Control
CCY1a
2.89 0.30
1.01 0.19**
0.86 0.20**
0.62 0.07**
7.60 0.36
C6H5
3
10
30
36.1 6.3
40.6 5.9
60.8 1.6
—
—
—
—
—
—
IC50 = 15.6
15
16
17
18
19
20
21
22
23
C6H5
3
10
30
1.96 0.19
1.05 0.16
0.48 0.05
31.8 3.3**
63.7 2.4**
83.2 1.4**
—
8.61 0.50
9.39 0.49
—
ꢀ13.5 6.0
ꢀ23.6 4.8
IC50 = 6.4 0.7
2-Cl-C6H4
3-Cl-C6H4
4-Cl-C6H4
2-F-C6H4
3-F-C6H4
4-CH3-C6H4
3
10
30
1.69 0.13
0.82 0.08
0.29 0.02
40.1 7.5**
71.4 2.3**
89.7 0.7**
—
9.86 0.27
8.39 0.36
—
ꢀ30.1 5.4
ꢀ10.9 7.0
IC50 = 4.4 1.1
3
10
30
2.00 0.26
0.9 90.12
0.34 0.04
31.2 1.8**
65.7 2.6**
88.0 1.5**
—
9.85 0.14
9.06 0.89
—
ꢀ30.1 5.6
ꢀ18.7 7.8
IC50 = 5.9 0.3
3
10
30
2.23 0.20
1.05 0.06
0.37 0.02
22.4 1.3
63.1 2.2**
86.9 1.3**
—
9.41 0.35
9.26 0.31
—
ꢀ23.9 3.1
ꢀ22.0 3.7
IC50 = 7.4 0.3
3
10
30
1.48 0.12
0.72 0.13
0.35 0.05
47.5 7.0**
75.1 2.3**
87.6 2.2**
—
9.45 0.64
9.82 0.51
—
ꢀ24.1 4.3
ꢀ29.4 6.0
IC50 = 3.3 0.8
3
10
30
1.70 .12
0.76 0.06
0.46 0.06
40.3 3.6**
73.0 3.4**
83.9 0.9**
—
8.07 0.26
9.38 0.39
—
ꢀ6.2 2.3
ꢀ23.7 6.5
IC50 = 4.5 0.7
3
10
30
2.24 0.15
1.57 0.11
0.78 0.12
21.9 2.8
45.1 1.9**
73.2 1.2**
—
8.53 0.48
9.51 0.18
—
ꢀ13.2 11.0
ꢀ25.8 7.7
IC50 = 11.0 0.4
4-OCH3-C6H4
3,4-Cl-C6H3
3
10
30
1.58 0.09
0.81 0.02
0.33 0.09
44.6 2.8**
71.3 1.8**
88.2 3.7**
—
9.45 0.51
9.28 0.31
—
ꢀ24.5 6.3
ꢀ22.2 1.9
IC50 = 3.8 0.5
1
3
2.56 0.35
2.03 0.21
0.60 0.20
—
11.7 3.1
29.4 2.4*
79.8 4.4**
—
—
—
—
10
30
7.77 0.29
11.4 0.48
1.9 6.3
ꢀ51.1 8.6*
—
IC50 = 4.3 0.4
24
25
26
31
2,3-Cl-C6H3
2,4-Cl-C6H3
2,6-Cl-C6H3
C6H5
10
30
10
30
10
30
1
2.39 0.27
17.4 0.8
39.9 4.9**
24.4 4.7
39.9 5.5**
40.3 7.5**
46.8 7.6**
26.7 4.1*
52.24 2.4**
81.2 1.0**
—
6.72 0.39
6.29 0.38
9.29 0.06
9.84 0.57
11.4 0.55
12.0 0.14
—
11.2 7.2
17.3 1.2
ꢀ22.7 6.6
ꢀ29.8 8.4
ꢀ50.6 5.3*
ꢀ59.2 7.6**
—
1.75 0.30
2.16 0.17
1.76 0.33
1.71 0.21
1.54 0.27
2.09 0.10
1.37 0.16
0.53 0.03
—
3
—
9.42 0.52
9.19 0.37
—
ꢀ24.0 5.4
ꢀ20.9 2.8
10
30
IC50 = 2.6 0.2

L.-J. Huang et al. / Bioorg. Med. Chem. Lett. 16 (2006) 2742–2747
2745
Table 1 (continued)
Compound
R0
Concentration (lM)
Superoxide formation (nmol/106 cells/30 min)
fMLP
% inhibition
PMA
% inhibition
32
33
2-Cl-C6H4
3-Cl-C6H4
10
30
1
1.89 0.18
1.69 0.13
2.54 0.17
1.82 0.20
0.67 0.22
—
34.3 2.6**
40.9 1.9**
11.4 3.4
36.8 1.4**
77.7 5.6**
—
8.94 0.59
9.63 0.39
—
ꢀ17.5 3.7
ꢀ26.9 5.4
—
3
—
10.3 0.91
9.96 0.67
10
30
ꢀ35.7 8.4
ꢀ31.2 7.7
IC50 = 4.2 0.3
34
35
4-Cl-C6H4
C6H5
10
30
3
2.10 0.21
1.90 0.08
2.03 0.08
1.05 0.08
0.48 0.05
27.1 0.5*
33.4 4.3**
41.9 3.4**
70.0 1.3**
86.0 1.9**
9.39 0.72
9.55 0.66
—
ꢀ23.3 6.0
ꢀ25.5 5.8
—
10
30
4.97 0.88
6.90 0.76
7.6 12.5
ꢀ29.4 8.3
IC50 = 4.3 0.5
36
2-Cl-C6H4
4-Cl-C6H4
3
10
30
2.45 0.30
2.09 0.23
0.78 0.11
29.5 10.5*
40.4 5.8**
77.7 2.9**
—
5.27 0.64
7.62 0.12
—
1.5 7.7
ꢀ44.4 4.7
IC50 = 9.5 1.4
37
10
30
2.53 0.22
2.41 1.4
27.9 4.6*
31.6 7.9**
11.9 0.25
12.1 0.15
ꢀ124 13.7**
ꢀ132 14.4**
TFP
1
3
—
—
5.48 0.13
3.4 0.13
—
27.6 4.2*
55.4 9.4**
—
28.0 0.27
2.1 0.09
0.54 0.22
1.7 6.6
24.2 5.3*
79.5 4.2**
5
10
1.23 0.16
83.3 5.8**
IC50 = 6.6 0.2
IC50 = 2.7 0.6
—, not determined. Trifluoperazine (TFP): positive control.
* P<0.05.
** P<0.01; N = 3.
neutrophil. Therefore, compound 31 was selected for
study of action mechanism.
We also determined the cAMP-elevating activity of
compound 31 in neutrophils by using an enzyme immu-
noassay kit (Amersham) as the previous report.1 Sur-
prisingly, compound 31 only slightly elevated the
cellular cAMP level at 10 lM and then returned to the
baseline at higher concentrations (Fig. 1), unlike
CCY1a, which produced a concentration-dependent in-
crease in cellular cAMP level. We next determined the
effect of compound 31 on intracellular free Ca2+ concen-
tration because the fMLP-induced superoxide anion is a
Ca2+-dependent process and CCY1a also exerts its
effect through the inhibition of Ca2+ entry.2 In this
experiment, neutrophils were loaded with 5 lM fluo-3
AM for 45 min. After being washed, the cells were
resuspended and monitored for the fluorescence change
(488/535 nm). Addition of fMLP to fluo-3-loaded
cells evoked an initial Ca2+ spike, followed by a
plateau phase, in the presence of 1 mM extracellular
Ca2+.8 Interestingly, compound 31 was 2.5-fold more
potent than CCY1a in the inhibition of plateau phase
(Fig. 2).
Figure 1. Effect of CCY1a and compound 31 on cellular cAMP levels.
Cells were treated with DMSO (as basal level), the indicated
concentrations of CCY1a or compound 31 for 10 min. The cAMP
contents were assayed using an enzyme immunoassay kit. Values are
means SD of three experiments.
both their lead compound and the positive control.
The action of the most potent compound 31 is
attributed at least partly to the blockade of intracel-
lular Ca2+ elevation but not to the cAMP-dependent
mechanism.
To sum up, the inhibitory activity for all of the
above CCY1a derivatives against neutrophil superox-
ide formation was found to be far superior than

2746
L.-J. Huang et al. / Bioorg. Med. Chem. Lett. 16 (2006) 2742–2747
1H), 7.77 (dd, J = 7.5, 1.6 Hz, 1H), 7.25–7.56 (m, 5H), 6.99
(d, J = 8.4 Hz, 1H), 6.96 (dd, J = 7.5, 7.5 Hz, 1H,), 6.79 (dd,
J = 16.0, 7.8 Hz, 1H), 5.13 (s, 2H) ppm; 13C NMR
(50 MHz, CDCl3):
d 194.35, 156.93, 147.59, 138.31,
134.64, 132.62, 130.06, 129.13, 128.67, 128.40, 127.37,
125.31, 123.38, 121.45, 112.68, 69.71 ppm; MS (EI) m/z
272 (M+); Anal. Calcd for: C, 70.46; H, 4.80. Found: C,
70.82; H, 5.04. Compound 18: yield, 43%; 1H NMR
(200 MHz, DMSO-d6): d 9.63 (d, J = 7.8 Hz, 1H), 7.90 (d,
J = 16.0 Hz, 1H), 7.72 (d, J = 7.5 Hz, 1H), 7.38–7.52(m,
5H), 7.16 (d, J = 8.4 Hz, 1H), 7.01 (dd, J = 7.5, 7.5 Hz, 1H),
6.83 (dd, J = 16.0, 7.8 Hz, 1H), 5.18 (s, 2H) ppm; 13C NMR
(50 MHz, DMSO-d6): d 194.73, 156.78, 147.63, 135.54,
132.76, 132.65, 129.46, 129.24, 129.01, 128.52, 122.69,
121.13, 113.19, 68.96 ppm; MS (EI) m/z 272 (M+); Anal.
Calcd for C16H13O2Cl: C, 70.46; H, 4.80. Found: C, 69.88 ;
H, 4.56. Compound 19: yield, 33%; 1H NMR (200 MHz,
DMSO-d6): d 9.60 (d, J = 7.8 Hz, 1H), 7.85 (d, J = 16.0 Hz,
1H), 7.75 (dd, J = 7.6, 1.4 Hz, 1H), 7.59 (ddd, J = 7.6, 7.6,
1.4 Hz, 1H), 7.41–7.47 (m, 2H), 7.21–7.32 (m, 3H), 7.04
(dd, J = 7.6, 7.6 Hz, 1H), 6.81 (dd, J = 16.0, 7.8 Hz, 1H),
5.28 (s, 2H) ppm; 13C NMR (50 MHz, DMSO-d6): d
195.17, 160.72, 157.10, 148.02, 133.15, 130.97, 130.89,
129.56, 124.85, 123.52, 122.97, 121.61, 115.73, 113.54,
64.56 ppm; MS (EI) m/z 256 (M+); Anal. Calcd for
C16H13O2F: C, 74.99; H, 5.11. Found: C, 73.56; H, 4.88.
Figure 2. Effect of compound 31 on the fMLP-stimulated elevation of
intracellular free Ca2+ in neutrophils. Fluo 3-loaded cells in HBSS
containing 1 mM Ca2+ were pretreated with the indicated concentra-
tions of compound 31 at 37 °C for 1 min before stimulation with
0.3 lM fMLP. The data presented are representative of three
independent experiments with similar results.
Acknowledgments
1
Compound 20: yield, 34%; H NMR (200 MHz, CDCl3): d
9.70 (d, J = 7.8 Hz, 1H), 7.91 (d, J = 16.0 Hz, 1H), 7.06 (dd,
J = 8.0, 1.6 Hz, 1H), 7.33–7.44 (m, 2H), 6.95–7.27 (m, 5H),
6.78 (dd, J = 16.0, 7.8 Hz, 1H), 5.17 (s, 2H) ppm; 13C NMR
(50 MHz, CDCl3): d 194.18, 156.78, 147.43, 138.54, 132.40,
130.15, 128.95, 128.49, 122.45, 122.31, 121.22, 114.95,
113.97, 112.47, 69.51 ppm; MS (EI) m/z 256 (M+); Anal.
Calcd for C16H13O2F: C, 74.99; H, 5.11. Found: C, 75.65;
H, 4.89. Compound 21: yield, 31%; 1H NMR (200 MHz,
CDCl3): d 9.67 (d, J = 7.8 Hz, 1H), 7.89 (d, J = 16.0 Hz,
1H), 7.58 (dd, J = 8.0, 1.8 Hz, 1H), 7.20–7.43 (m, 4H),
6.97–7.05 (m,2H), 6.77 (dd, J = 16.0, 7.8 Hz, 1H), 5.13 (s,
2H), 2.38 (s, 3H) ppm; 13C NMR (50 MHz, CDCl3): d
194.52, 157.45, 147.41, 138.09, 133.21, 132.61, 129.41,
128.98, 128.66, 127.54, 123.36, 121.09, 112.82, 70.54,
21.20 ppm; MS (EI) m/z 252 (M+); Anal. Calcd for
C17H16O2: C, 80.93; H, 6.39. Found: C, 79.88; H, 6.54.
This work was supported by research grants from the
National Science Council of the Republic of China
(NSC91-2320-B-039-039) and in part by China Medical
University (CMC90-PC-03) awarded to L. J. Huang.
References and notes
1. Chang, C. Y.; Kuo, S. C.; Lin, Y. L.; Wang, J. P.; Huang,
L. J. Bioorg. Med. Chem. Lett. 2001, 11, 1971.
2. Wang, J. P.; Chang, L. C.; Lin, Y. L.; Hsu, M. F.; Chang,
C. Y.; Huang, L. J.; Kuo, S. C. Biochem. Pharmacol. 2003,
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3. Wang, J. P.; Chang, L. C.; Kuan, Y. H.; Tsao, L. T.;
Huang, L. J.; Kuo, S. C. Naunyn-Schmiedeberg’s Arch.
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1
Compound 22: yield, 32%; H NMR (200 MHz, CDCl3): d
9.66 (d, J = 7.8 Hz, 1H), 7.88 (d, J = 16.0 Hz, 1H), 7.58 (dd,
J = 8.0, 1.8 Hz, 1H), 7.34–7.40 (m, 3H), 6.92–7.05 (m, 4H),
6.73 (dd, J = 16.0, 7.8 Hz, 1H), 5.10 (s, 2H), 3.83 (s,
3H) ppm; 13C NMR (50 MHz, CDCl3): d 194.54, 159.66,
157.49, 148.08, 132.62, 123.39, 121.11, 114.15, 112.87,
70.44, 55.33 ppm; MS (EI) m/z 268 (M+); Anal. Calcd for
C17H16O3: C, 76.10; H, 6.01. Found: C, 76.58; H, 5.98.
Compound 23: yield, 22%; 1H NMR (200 MHz, DMSO-
d6): d 9.64 (d, J = 7.8 Hz, 1H), 7.92 (d, J = 16.0 Hz, 1H),
7.75–7.77 (m, 2H), 7.66 (d, J = 8.3 Hz, 1H), 7.41–7.50 (m,
2H), 7.17 (d, J = 8.4 Hz, 1H), 7.03 (dd, J = 7.5, 7.5 Hz, 1H),
6.83 (dd, J = 16.0, 7.8 Hz, 1H), 5.25 (s, 2H) ppm; 13C NMR
(50 MHz, DMSO-d6): d 194.92, 156.59, 147.65, 137.83,
132.89, 131.20, 130.84, 130.63, 129.68, 129.29, 129.13,
127.97, 122.76, 121.37, 113.30, 68.29 ppm; MS (EI) m/z
306 (M+); Anal. Calcd for C16H12O2Cl2: C, 62.56; H, 3.94.
Found: C, 63.51; H, 4.05. Compound 24: yield, 24%; 1H
NMR (200 MHz, CDCl3): d 9.71 (d, J = 7.8 Hz, 1H), 7.93
(d, J = 16.0 Hz, 1H), 7.61 (dd, J = 7.5, 1.4Hz, 1H), 7.36–
7.49 (m, 3H), 7.22–7.29 (m, 1H), 7.05 (d, J = 7.5, 7.5 Hz,
1H), 6.95 (d, J = 8.4 Hz, 1H), 6.78 (dd, J = 16.0, 7.8 Hz,
1H), 5.28 (s, 2H) ppm; 13C NMR (50 MHz, CDCl3): d
194.31, 156.66, 147.50, 136.22, 133.31, 132.68, 130.75,
129.97, 129.10, 128.59, 127.56, 126.61, 123.35, 121.62,
112.72, 67.98 ppm; MS (EI) m/z 306 (M+); Anal. Calcd
4. Wang, J. P.; Chang, L. C.; Hsu, M. F.; Huang, L. J.; Kuo,
S. C. Biochim. Biophys. Acta 2002, 1573, 26.
5. Lin, C. F.; Yang, J. S.; Chang, C. Y.; Kuo, S. C.; Lee, M.
R.; Huang, L. J. Bioorg. Med. Chem. 2005, 13, 1537.
6. Spectral characteristics for compounds: Compound 15:
yield, 42%; 1H NMR (200 MHz, DMSO-d6): d 9.63 (d,
J = 7.8 Hz, 1H), 7.90 (d, J = 16.0 Hz, 1H), 7.73 (d,
J = 7.5 Hz, 1H), 7.29–7.50 (m, 6H), 7.19 (d, J = 8.4 Hz,
1H), 7.02 (dd, J = 7.5, 7.5 Hz, 1H), 6.75 (dd, J = 16.0,
7.8 Hz, 1H), 5.23 (s, 2H) ppm; 13C NMR (50 MHz, DMSO-
d6): d 194.80, 157.02, 147.79, 136.56, 133.26, 132.80, 129.35,
129.03, 128.54, 127.98, 127.65, 122.68, 121.04, 69.81 ppm;
MS (EI) m/z 238 (M+); Anal. Calcd for C16H14O2: C, 80.65;
H, 5.92. Found: C, 79.98; H, 5.86. Compound 16: yield,
35%; 1H NMR (200 MHz, DMSO-d6):
d 9.62 (d,
J = 7.8 Hz, 1H), 7.89 (d, J = 16.0 Hz, 1H), 7.70 (d,
J = 7.5, 1.2 Hz, 1H,), 7.37–7.65 (m, 5H), 7.23 (d,
J = 7.2 Hz, 1H), 7.05 (dd, J = 7.5, 7.5 Hz, 1H), 6.82 (dd,
J = 16.0, 7.8 Hz, 1H), 5.29 (s, 2H) ppm; 13C NMR
(50 MHz, DMSO-d6): d 194.82, 156.78, 147.58, 133.80,
133.32, 132.90, 130.38, 129.54, 129.32, 129.12, 127.48,
121.38, 120.13, 67.62 ppm; MS (EI) m/z 272 (M+); Anal.
Calcd for C16H13O2Cl: C, 70.46; H, 4.80. Found: C, 70.32;
H, 4.68. Compound 17: yield, 31%; 1H NMR (200 MHz,
CDCl3): d 9.62 (d, J = 7.8 Hz, 1H), 7.88 (d, J = 16.0 Hz,

L.-J. Huang et al. / Bioorg. Med. Chem. Lett. 16 (2006) 2742–2747
2747
for C16H12O2Cl2: C, 62.56; H, 3.94. Found: C, 63.21; H,
4.01. Compound 25: yield, 42%; 1H NMR (200 MHz,
DMSO-d6): d 9.62 (d, J = 7.8 Hz, 1H), 7.89 (d, J = 16.0 Hz,
1H), 7.77 (d, J = 7.5 Hz, 1H), 7.71 (d, 1H), 7.63 (m, 1H),
7.47–7.51 (m, 2H), 7.05 (d, J = 8.4 Hz, 1H), 6.95 (dd,
J = 7.5, 7.5 Hz, 1H), 6.78 (dd, J = 16.0, 7.8 Hz, 1H), 5.27 (s,
2H) ppm; 13C NMR (50 MHz, DMSO-d6): d 194.90,
156.63, 147.52, 133.87, 133.05, 132.95, 131.72, 129.29,
129.14, 127.70, 122.84, 121.53, 113.36, 67.06 ppm; MS
(EI) m/z 306 (M+); Anal. Calcd for C16H12O2Cl2: C, 62.56;
H, 3.94. Found: C, 62.54; H, 3.88. Compound 26: yield,
1H NMR (200 MHz, DMSO-d6): d 9.64 (d, J = 7.8 Hz, 1H),
7.89 (d, J = 16.0 Hz, 1H), 7.31–7.48 (m, 6H), 7.13 (d,
J = 9.1 Hz, 1H), 7.01 (dd, J = 9.1, 3.0 Hz, 1H), 6.90 (dd,
J = 16.0, 7.8 Hz, 1H), 5.16 (s, 2H), 3.74 (s, 3H) ppm; 13C
NMR (50 MHz, DMSO-d6): d 194.89, 153.39, 151.30,
147.47, 136.81, 129.24, 128.52, 127.94, 127.66, 123.43,
118.83, 114.93, 112.97, 70.41, 55.59 ppm; MS (EI) m/z 268
(M+); Anal. Calcd for C17H16O3: C, 76.10; H, 6.01. Found:
C, 76.01; H, 6.11. Compound 32: yield, 55%; 1H NMR
(200 MHz, DMSO-d6): d 9.62 (d, J = 7.8 Hz, 1H), 7.87 (d,
J = 16.0 Hz, 1H), 7.35–7.61 (m, 4H), 7.31 (d, J = 3.0 Hz,
1H), 7.16 (d, J = 9.1 Hz, 1H), 7.03 (dd, J = 9.1, 3.0 Hz, 1H),
6.88 (dd, J = 16.0, 7.8 Hz, 1H), 5.21 (s, 2H), 3.75 (s,
3H) ppm; 13C NMR (50 MHz, DMSO-d6): d 194.73,
153.63, 151.02, 147.20, 134.01, 132.73, 130.284, 129.99,
129.46, 129.23, 127.40, 123.65, 118.83, 115.04, 112.81,
68.26, 55.57 ppm; MS (EI) m/z 276 (M+); Anal. Calcd for
C17H15O3Cl: C, 67.44; H, 4.99. Found: C, 66.99; H, 5.01.
Compound 33: yield, 39%; 1H NMR (200 MHz, DMSO-
d6): d 9.65 (d, J = 7.8 Hz, 1H), 7.90 (d, J = 16.0 Hz, 1H),
7.52 (s, 1H), 7.31–7.44 (m, 3H),7.31 (d, J = 2.7 Hz, 1H),
7.12 (d, J = 9.1 Hz, 1H), 7.03 (dd, J = 9.1, 2.7 Hz, 1H), 6.89
(dd, J = 16.0, 7.8 Hz, 1H), 5.19 (s, 2H), 3.74 (s, 3H) ppm;
13C NMR (50 MHz, DMSO-d6): d 194.95, 153.54, 151.00,
147.38, 139.44, 133.18, 130.51, 129.33, 127.92, 127.44,
126.27, 123.53, 118.86, 114.97, 112.93, 69.51, 55.61 ppm;
MS (EI) m/z 302 (M+); Anal. Calcd forC17H15O3Cl: C,
67.44; H, 4.99. Found: C, 66.99; H, 5.01. Compound 34:
yield, 32%; 1H NMR (200 MHz, DMSO-d6): d 9.60 (d,
J = 7.8 Hz, 1H), 7.89 (d, J = 16.0 Hz, 1H), 7.42–7.52 (m,
4H), 7.31 (d, J = 2.9 Hz, 1H), 7.13 (d, J = 9.1 Hz, 1H), 7.02
(dd, J = 9.1, 2.9 Hz, 1H), 6.88 (dd, J = 16.0, 7.8 Hz, 1H),
5.18 (s, 2H), 3.74 (s, 3H) ppm; 13C NMR (50 MHz, DMSO-
d6):d 194.93, 153.50, 151.08, 147.36, 135.88, 132.55, 129.57,
129.28, 128.54, 123.49, 118.85, 114.96, 112.93, 69.58,
55.61 ppm; MS (EI) m/z 302 (M+); Anal. Calcd for-
C17H15O3Cl: C, 67.44; H, 4.99. Found: C, 67.32; H, 5.02.
7. Wang, J. P.; Raung, S. L.; Kuo, Y. H.; Teng, C. M. Eur. J.
Pharmacol. 1995, 288, 341.
27%; 1H NMR (200 MHz, DMSO-d6):
d 9.52 (d,
J = 7.8 Hz, 1H), 7.73 (d, J = 16.0 Hz, 1H), 7.72 (d,
J = 1.2 Hz, 1H), 7.35–7.60 (m, 5H), 7.08 (dd, J = 7.5,
7.5 Hz, 1H), 6.73 (dd, J = 16.0, 7.8 Hz, 1H), 5.34 (s,
2H) ppm; 13C NMR (50 MHz, DMSO-d6): d 194.92,
157.35, 147.65, 136.32, 133.18, 132.00, 131.45, 129.74,
129.41, 129.12, 123.14, 121.94, 113.83,66.11 ppm; MS (EI)
m/z 306 (M+); Anal. Calcd for C16H12O2Cl2: C, 62.56; H,
3.94. Found: C, 61.22; H, 4.02. Compound 28: yield, 79%;
1H NMR (200 MHz, DMSO-d6): d 10.30 (s, 1H), 7.26–7.38
(m, 4H), 7.25 (d, J = 2.8Hz, 1H), 7.15 (d, J = 2.8Hz, 1H),
5.23 (s, 2H), 3.72 (s, 3H) ppm; 13C NMR (50 MHz, DMSO-
d6): d 189.14, 155.13, 153.78, 134.00, 132.87, 130.31, 129.67,
127.64, 125.36, 123.24, 116.53, 110.57, 68.69, 55.75 ppm;
MS (EI) m/z 276(M+); Anal. Calcd for C15H13O3Cl: C,
65.11; H, 4.74. Found: C, 64.99; H, 5.02. Compound 29:
yield, 73%; 1H NMR (200 MHz, DMSO-d6): d 10.37 (s,
1H), 7.52 (s, 1H), 7.35–7.41 (m, 3H), 7.18 (m, 3H), 5.17 (s,
2H), 3.17 (s, 3H) ppm; 13C NMR (50 MHz, DMSO-d6): d
188.91, 155.03, 153.63, 139.33, 133.50, 130.49, 128.04,
127.40, 126.15, 125.15, 122.96, 115.91, 110.65, 69.74,
55.60 ppm; MS (EI) m/z 276(M+); Anal. Calcd for
C15H13O3Cl: C, 65.11; H, 4.74. Found: C, 65.32; H, 4.74.
Compound 30: yield, 63%; 1H NMR (200 MHz, DMSO-
d6): d 10.36, (s, 1H), 7.39–7.51 (m, 4H), 7.16–7.21 (m, 3H),
5.19 (s, 2H), 3.72 (s, 3H) ppm; 13C NMR (50 MHz, DMSO-
d6): d 188.79, 154.89, 153.38, 135.62, 132.54, 129.37, 128.45,
124.94, 122.88, 115.98, 110.30, 69.63, 55.47 ppm; MS (EI)
m/z 276 (M+); Anal. Calcd for C15H13O3Cl: C, 65.11; H,
4.74. Found: C, 65.21; H, 4.69. Compound 31: yield, 35%;
8. Merritt, J. E.; McCarthy, S. A.; Davies, M. P.; Morres, K.
E. Biochem. J. 1990, 269, 513.