Synthesis and structure-activity relationship of N-(2-arylethyl) isoquinoline derivatives as human scavenger receptor CD36 antagonists

Article abstract of DOI:10.1016/j.ejmech.2011.01.022

By using human scavenger receptor CD36 as the target, twenty-five N-(2-arylethyl) isoquinoline derivatives were designed, synthesized and evaluated for their antagonistic activities for CD36-oxidatively low density lipoprotein (oxLDL) binding. The primary analysis of structure-activity relationship (SAR) indicated a methoxyl at the 7-position and a hydroxyl at the 6- or 8-position could afford good activities. Among these analogs, compounds 7e and 7t showed the potential CD36 antagonistic activities with IC₅₀ values of 0.2 and 0.8 μg/mL, respectively. Furthermore, both of them could effectively inhibit oxLDL uptake in insect Sf9 cells overexpressing human CD36, and thus have been selected for further investigation. We consider N-(2-arylethyl) isoquinoline analogs to be a family of novel CD36 antagonists.

Full text of DOI:10.1016/j.ejmech.2011.01.022

European Journal of Medicinal Chemistry 46 (2011) 1066e1073
Contents lists available at ScienceDirect
European Journal of Medicinal Chemistry
journal homepage: http://www.elsevier.com/locate/ejmech
Original article
Synthesis and structureeactivity relationship of N-(2-arylethyl) isoquinoline
derivatives as human scavenger receptor CD36 antagonists
Yan-Xiang Wang 1, Li Wang 1, Yan-Ni Xu, Ying-Hong Li, Jian-Dong Jiang, Shu-Yi Si, Yang-Biao Li, Gang Ren,
**
*
Yong-Qiang Shan, Bin Hong , Dan-Qing Song
Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China
a r t i c l e i n f o
a b s t r a c t
Article history:
By using human scavenger receptor CD36 as the target, twenty-five N-(2-arylethyl) isoquinoline deriv-
atives were designed, synthesized and evaluated for their antagonistic activities for CD36-oxidatively low
density lipoprotein (oxLDL) binding. The primary analysis of structureeactivity relationship (SAR) indi-
cated a methoxyl at the 7-position and a hydroxyl at the 6- or 8-position could afford good activities.
Among these analogs, compounds 7e and 7t showed the potential CD36 antagonistic activities with IC50
Received 16 September 2010
Received in revised form
5 January 2011
Accepted 12 January 2011
Available online 21 January 2011
values of 0.2 and 0.8
mg/mL, respectively. Furthermore, both of them could effectively inhibit oxLDL
uptake in insect Sf9 cells overexpressing human CD36, and thus have been selected for further inves-
tigation. We consider N-(2-arylethyl) isoquinoline analogs to be a family of novel CD36 antagonists.
Ó 2011 Elsevier Masson SAS. All rights reserved.
Keywords:
N-(2-Arylethyl) isoquinoline
CD36 Antagonist
Oxidized low density lipoprotein
Structureeactivity relationship
1. Introduction
CD36 binding and be developed to a novel class of anti-athero-
sclerotic agents. The screening of small molecule CD36 antagonists
Atherosclerosis (AS) is a progressive chronic inflammatory
disease characterized by a gradual thickening and hardening of the
arterial wall and becomes the primary cause of coronary artery and
cerebrovascular disease. Binding and uptake of oxidatively low
density lipoproteins (oxLDL) by macrophages is one of the earliest
steps in the development of atherosclerotic lesions and lipid-laden
foam cells that constitute the atherosclerotic lesion core [1e3].
Monocyte/macrophage CD36, as a scavenger receptor, has been
shown to play a critical role in the development of atherosclerotic
lesions by its capacity to bind and endocytose oxLDL into macro-
phages, which is implicated in the formation of foam cells [4e8].
CD36 is a member of the multi-ligand scavenger receptor class B
family present on the surface of a number of cells such as platelets,
monocytes/macrophages, endothelial and smooth muscle cell
[9,10]. Since CD36 was discovered as a macrophage receptor for
oxLDL, it could played a major role in the initiation of atheroscle-
rotic process and be considered as the target against AS [11,12].
Therefore, CD36 antagonists might be useful in blocking oxLDL-
may be one of the approaches to discover the potential drug
candidates against AS [13].
During the course of synthesis of berberine (BBR, Fig. 1) analogs
as a kind of LDLR mRNA up-regulators [14e16], a new class of
compound, 7-hydroxy-2-{2-[3-(trifluoromethyl)phenyl]ethyl}iso-
quinolinium chloride (1, Fig. 1) was obtained accidently and
identified structurally. However, compound 1 lost its activity on up-
regulatory LDLR expression in comparison with BBR (data not
shown). The factor contributes to the activity loss is presumable the
configurational change of BBR and 1. The planar structure con-
verted into bended one at the carbonecarbon single bond between
the ring A and C. Screened by the models developed in our labo-
ratory, we found that compound 1 showed a potential antagonistic
activity for CD36-oxLDL binding with IC50 value of 1.2
greater than that of positive control hexarelin (Fig. 1) with IC50
value of 46.8 g/mL [17].
mg/mL much
m
The novel biological activity and unique chemical structure of 1
provoked our strong interest to explore the structureeactivity
relationship (SAR) of this kind of compounds for CD36-oxLDL
antagonistic activities. Taking compound 1 as the lead, we initiated
the SAR analysis on the modifications of substituents on the ring D,
A and C, respectively, on which twenty-five new isoquinoline
derivatives were designed, synthesized and evaluated for their
antagonistic activities for CD36-oxLDL binding in the present study.
* Corresponding author. Tel./fax: þ86 10 6316 5268.
** Corresponding author. Tel./fax: þ86 10 6302 8003.
E-mail addresses: binhong69@hotmail.com (B. Hong), songdanqingsdq@
hotmail.com (D.-Q. Song).
1
These authors made equal contributions to the work.
0223-5234/$ e see front matter Ó 2011 Elsevier Masson SAS. All rights reserved.
doi:10.1016/j.ejmech.2011.01.022

Y.-X. Wang et al. / European Journal of Medicinal Chemistry 46 (2011) 1066e1073
1067
Fig. 1. Chemical structures of BBR, 1 and hexarelin.
2. Chemistry
their antagonistic activities for CD36-oxLDL binding with hexarelin
as a positive control are shown in Table 1.
The twenty-five compounds were synthesized through a four-
step process (Scheme 1), using commercially available derivatives
of phenylethylamine (2) and benzaldehyde (3) as starting mate-
rials with the methods reported previously [14e16]. In the inter-
molecular cyclization of the intermediate 5, ring B could not
cyclize without assistance of activating groups (such as hydroxyl,
methyl or methoxyl) at the 30- or 50-position of the ring A
according to PicteteSpengler reaction rule, and subsequently the
key intermediate 6 would be obtained with the yields of 28e53%.
The crude products in 7 series were prepared by the acidification
of intermediate 6. The final products (7aev) were purified via flash
column chromatography using methanol/dichloromethane as the
eluent. In the other hand, the ring B and C might form simulta-
neously while an activating group exists at the same position on
the ring A, thus BBR analogs were synthesized [14e16].
The SAR study was first focused on the substituents on the
aromatic ring A and D of compound 1. Retaining the hydroxyl at the
7-position and replacing trifluoromethyl with a hydrogen, fluoro or
methoxyl at position 20 or 40, respectively, by which three analogs
(7aec) were created. The results showed that all of them lost their
antagonistic activities on CD36 partially or completely. Instead of
the hydroxyl of 7a with a methoxyl at position 7 (7d) afforded
a moderated activity similar to that of 1. It seems that the methoxyl
at position 7 might be beneficial for the activity.
Next, SAR analysis was concentrated on the di-substituted side-
chains of the ring D. Retainment of the methoxyl at position 7 and
introduction of a hydroxyl at the 8-position, with which four
analogs (7eeh) were synthesized. Compound 7e without substit-
uents on the ring A afforded the most potent activity in CD36
antagonism with about 1.6-fold increase over that of 1. Other
compounds (7feh) bearing a methyl, fluoro or methoxyl at the 20-
or 40-position exhibited a partial or complete loss in CD36 antag-
onistic activities.
In another variation, dimethoxy was attached at the 7-, 8-
positions of the ring D, from which four compounds (7iel) were
generated. Compounds 7jek possessing a methyl or fluoro at the
20- or 30-position respectively had activities similar to that of 1.
Compound 7i and 7l showed decreased antagonistic activities on
CD36. Additionally, moving the methoxyl from the 8- to 6-position,
five analogs (7meq) were obtained. The results showed that
movement of the methoxyl from the 8- to 6-position on the ring D
resulted in a partial or complete loss of activity regardless of the
size, position and electronic effect of groups on the ring A.
Furthermore, replacing the methoxyl with a hydroxyl at the
6-position, compounds 7rev bearing a hydrogen, fluoro, chloro or
methoxyl at the 30- or 40-position, respectively, were made
and tested. Compound 7t with 40-methoxyl showed a CD36
In the course of intermolecular cyclization of 5, another key
intermediate 8 was obtained as well, when the amount of the
dehydrating agent-CuSO4 was deduced to half level and the cycli-
zation time was shortened from 5 h to 1 h. The final products
(9aec) were obtained with the same procedures of 7 series with
a good yield.
3. Results and discussion
3.1. SAR analysis for the CD36 antagonistic activity
The high throughput screening (HTS) of enzyme-linked immu-
nosorbent assay (ELISA)-like constructed in our laboratory [17] was
used for initial biological screening at the level of CD36-ligand
binding. The extracellular domain of human CD36 expressed in
Escherichia coli as a His-tagged protein, had been demonstrated to
bind oxLDL specifically. Structures of the twenty-five analogs and

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Y.-X. Wang et al. / European Journal of Medicinal Chemistry 46 (2011) 1066e1073
HCl
CHO
R
R
N
HN
NH2
b
a
+
R
R'
R'
R
R'
5
2
3
4
Cl-
+ COOH-
N+
R
N
c
e
f
R'
R'
7a-v
6
+ COOH-
Cl-
R
R
N+
N
e
d
HO
f
HO
R'
R'
9a-c
8
Scheme 1. Synthesis of the study compounds. Reagents and conditions: (a) 70 ꢀC, 1 h; (b) NaBH4, methanol, reflux, 4 h; (c) glyoxal, formic acid, CuSO4, HCl, 100 ꢀC, 5 h; (d) glyoxal,
formic acid, CuSO4, HCl, 100 ꢀC, 1 h; (e) methanol/H2O, CaO, r.t., 2 h; (f) ethanol/HCl, r.t., 0.5 h.
antagonistic activity greater than 1 did. Also, compound 7u pos-
sessing a fluoro at the same position exhibited a moderated activity
in respect to 1. We therefore deduced that a methoxyl and hydroxyl
at the 7- and 6-position, respectively, was an optimal combination
for the structure in their antagonistic activity on CD36.
The preliminary SAR analysis of ring B was carried out as well.
We retained the active fragment of the ring D, i.e. 7-methoxyl and
8-hydroxyl, and introduced a hydroxyl at the 3-position of the ring
C, with which three compounds (9aec) were designed and
synthesized. The results showed that all of them almost lost their
activities on CD36. We considered the quaternary ammonium ion
at the 2-position to be an important role in binding to speculated
biological targets. The lone pair electrons in hydroxyl at position 3
might form an electrostatic attraction with quaternary ammonium
ion and reduce its electro-positivity, and subsequently interfere
with the bioactivity of the analogs.
3.3. Fluorescence microscopic analysis
Since compounds 7e and 7t afforded the potential CD36
antagonistic activities, and thus their antagonistic effect was
further examined using fluorescence microscopy in Sf9[hCD36]
cells. The amounts of fluorescence in the cells incubated with DiI-
AcLDL (5 mg/mL) plus compounds 7t or 7e (10 mg/mL) were obvi-
ously lower (Fig. 4C,D) than those in the cells with DiI-AcLDL alone
(Fig. 4A), suggesting that both of them could inhibit DiI-AcLDL
uptake in Sf9[hCD36] cells by antagonizing CD36-oxLDL binding.
OxLDL (40 mg/mL) was used as positive control, and there was no
fluorescence uptake (Fig. 4B).
4. Conclusion
In conclusion, we have synthesized twenty-five N-(2-arylethyl)
isoquinoline analogs with different substituents on the ring A, B or
C and studied the biological effect as CD36 antagonists. The results
suggested that the compounds with a methoxyl at position 7 and
a hydroxyl at the 6- or 8-position showed the potent activities. The
hydroxyl at either 6- or 8-position might provide a beneficial
shoring effect for the 7-methoxyl to obtain an optimal steric
conformation. These results are of interest to establish the SAR of N-
(2-arylethyl) isoquinoline analogs, and provide the basis for further
chemical investigation. As compounds 7e and 7t showed the
potential antagonistic activities for CD36-oxLDL binding on both
the molecular and cellular levels, they have been selected for the
next-step evaluation in animal experiments.
Among those analogs, the compounds 7e, 7jek and 7teu
afforded the potential CD36 antagonistic effects in comparison with
1, and thus their dose-dependent competition assays were further
performed. As shown in Fig. 2, the five compounds showed CD36
antagonistic effect with IC50 values ranging from 0.2 to 2.4
Especially, compounds 7e and 7t are the promising CD36 antago-
nists with IC50 values of 0.2 and 0.8 g/mL, respectively.
mg/mL.
m
3.2. The CD36 antagonistic effect at the cellular level
To confirm the effects of the compounds (1, 7e, 7jek, 7teu)
screened from the above HTS assay, the assay for CD36 antagonists
in Spodoptera frugiperda (Sf9) cells overexpressing human CD36
(Sf9[hCD36]) developed in our laboratory [18] was used to examine
5. Experimental section
the activities of the hits. OxLDL (40 mg/mL) was used as a positive
control, and its inhibitory activity was defined as 100%. As shown in
Fig. 3, all of them could inhibit 1, 10-dioctadecyl-3, 3, 30, 30-tet-
ramethylindocarbo cyanine perchlorate labeled acetylated LDL
(DiI-AcLDL) uptake in Sf9[hCD36] cells at different levels, and their
activities were just agreeable with those in CD36-oxLDL binding
assay. The results indicated that the compounds could inhibit
natural ligands binding CD36 at both cellular and molecular levels.
5.1. Chemistry
Unless otherwise noted, all commercial reagents and solvents
were obtained from the commercial provider and used without
further purification. 1H NMR and 13C NMR spectra were recorded on
Varian 400 MHz spectrometers. Chemical shifts were reported rela-
tive to internal tetramethylsilane. Flash column chromatography was

Y.-X. Wang et al. / European Journal of Medicinal Chemistry 46 (2011) 1066e1073
1069
Table 1
CD36 receptor antagonistic effect of study analogs.
R1
R2
+ Cl-
A
N
R3
C
R4
R8
R7
D
R6
Compd
R1
R2 R3
R4 R6
R7
R8
Inhibition rate (%)a
Hexarelinb
1
7a
7b
7c
7d
7e
37.6 ꢃ 1.8
48.4 ꢃ 3.7
<10
21.7 ꢃ 3.8
28.7 ꢃ 4.0
47.4 ꢃ 2.6
77.9 ꢃ 11.5
11.5 ꢃ 6.2
29.6 ꢃ 15.7
<10
H
H
F
H
H
H
CH3
H
H
H
CH3
H
H
H
H
H
H
H
H
H
H
H
H
H
CH3
H
CF3
H
H
H
H
H
H
H
H
H
H
F
H
H
H
OCH3
H
H
H
F
OCH3
H
H
H
Cl
H
H
H
OCH3
Cl
H
H
OCH3
F
Cl
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
OH
OH
OH
OH
H
H
H
H
H
OCH3
OCH3 OH
OCH3 OH
OCH3 OH
OCH3 OH
7f
7g
7h
7i
7j
7k
7l
7m
7n
7o
7p
7q
7r
7s
7t
7u
7v
9a
OCH3 OCH3 <10
OCH3 OCH3 46.6 ꢃ 4.8
OCH3 OCH3 52.1 ꢃ 13.4
OCH3 OCH3 25.4 ꢃ 5.6
H
H
F
OCH3 OCH3
OCH3 OCH3
OCH3 OCH3
OCH3 OCH3
OCH3 OCH3
OH
OH
OH
OH
OH
H
H
H
H
H
H
H
H
H
H
H
H
H
10.0 ꢃ 1.0
20.9 ꢃ 3.3
<10
CF3
H
H
H
Cl
H
H
H
Cl
H
F
28.6 ꢃ 1.2
<10
OCH3
OCH3
OCH3
OCH3
OCH3
OCH3
OCH3
OCH3
31.0 ꢃ 3.0
33.6 ꢃ 9.8
76.3 ꢃ 2.0
42.4 ꢃ 17.6
<10
OH OH
OH OH
OH OH
33.2 ꢃ 7.3
9b
9c
<10
<10
a
OxLDL (5
m
g/mL) was first coated and then blocked with 1% BSA. Later, CD36
M) and study compounds
g/mL) for 2 h. The inhibition of oxLDL binding with CD36 was determined by
Fig. 2. The dose-response curves of the active compounds (10
m
g/mL) for CD36-oxLDL
(30
(10
mg/mL) was added to incubate with hexarelin (10 m
m
antagonistic effect.
OD450 values. The untreated control was defined as 1, and the inhibition of analogs
was calculated with the formulation: inhibition rate (%) ¼ (1 ꢂ OD450 of compounds/
OD450 of untreated control) ꢁ 100. The data shown were mean values of at least 3
added dropwise to adjust PH of the organic layer to 5e6, and
filtered to give the hydrochlorate (5) without further purification.
To a suspension of anhydrous CuSO4 (3.6 equiv) and 5 (1.0 equiv)
in anhydrous formic acid (45 mL) was added glyoxal (40%,
2.0 equiv) at 100 ꢀC. The reaction mixture was stirred at 100 ꢀC for
5 h, concentrated hydrochloric acid (0.8 and 0.6 equiv) was added
at 2 h and 4 h respectively during this process. Upon completion, as
determined by TLC, the mixture was filtered. The filtrate was
concentrated in vacuo. The residue (6) was dissolved in methanol
(500 mL) and water (10 mL), CaO was added portionwise to adjust
PH to 9e10. The suspension was stirred at the r.t. for 2 h, filtered
and concentrated in vacuo. The resulting residues were purified via
flash column chromatography using methanol/dichloromethane as
the eluent, and then acidified by 10% HCl/ethanol to give 7.
separate experiments.
b
The concentration of hexarelin was 10 mM.
performed on 200e400 mesh silica gel. Thin layer chromatography
(TLC) was performed using E. Merck silica gel 60 F254 precoated
plates. Melting points (m.p.) are uncorrected and were recorded on
a Büchi capillary melting point apparatus.
5.1.1. General procedure for N-(2-arylethyl) isoquinolines analogs
(7aev)
A 250 mL round bottom flask was charged with 2 (1.0 equiv)
and 3 (1.0 equiv) at 70 ꢀC, and the mixture was stirred under
vacuum for 1 h. Methanol (100 mL) was added to the residue,
and then NaBH4 (3.0 equiv) was added portionwise at the r.t.
The mixture was refluxed for 4 h. Upon completion, as determined
by TLC, the reaction mixture was concentrated in vacuo. The
residue was dissolved in water (300 mL). The resulting aqueous
phase was extracted with ethyl acetate (3 ꢁ 100 mL) and the
combined organic layers were rinsed with saturated brines
(100 mL) and dried (Na2SO4). Concentrated hydrochloric acid was
5.1.1.1. 7-Hydroxy-2-{2-[3-(trifluoromethyl)phenyl]ethyl}iso-
quinolinium chloride (1). Yield: 42%; mp: 100e102 ꢀC (decomp);
Dark red solid; 1H NMR (DMSO-d6, ppm):
d 11.21 (s, br,1H, OH), 9.73
(s, 1H, 8-CH), 8.54 (d, 1H, J ¼ 6.8 Hz, Ph), 8.44 (d, 1H, J ¼ 6.8 Hz, Ph),
8.20 (d, 1H, J ¼ 8.8 Hz, Ph), 7.77 (d, 1H, J ¼ 8.8 Hz, Ph), 7.54 (m, 5H,
Ph), 4.91 (t, 2H, J ¼ 7.6 Hz, CH2), 3.44 (t, 2H, J ¼ 7.6 Hz, CH2). HRMS-
ESI calcd for C18H15NOF3Cl: 319.1184 [M þ H ꢂ Cl]þ, found 319.1171.

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Y.-X. Wang et al. / European Journal of Medicinal Chemistry 46 (2011) 1066e1073
1
0.8
0.6
0.4
0.2
0
(d, 1H, J ¼ 8.8 Hz, Ph), 7.32 (d, 1H, J ¼ 8.8 Hz, Ph), 7.14 (s, 1H, Ph), 7.12
(s, 1H, Ph), 6.83 (s, 1H, Ph), 6.81 (s, 1H, Ph), 6.70 (s, 1H, OH), 4.67 (t,
2H, J ¼ 6.8 Hz, CH2), 3.68 (s, 3H, OCH3), 3.20 (t, 2H, J ¼ 6.8 Hz, CH2).
HRMS-ESI calcd for C18H18NO2Cl: 280.1338 [M ꢂ Cl]þ, found
280.1343.
5.1.1.4. 2-[2-(2-Fluorophenyl)ethyl]-7-hydroxyisoquinolinium chlo-
ride (7c). Yield: 36%; mp: 97e99 ꢀC (decomp); Brown solid; 1H
NMR (DMSO-d6, ppm): d 11.22 (s, br,1H, OH), 9.70 (s,1H, 8-CH), 8.51
(d, 1H, J ¼ 6.8 Hz, Ph), 8.41 (d, 1H, J ¼ 6.8 Hz, Ph), 8.20 (d, 1H,
J ¼ 7.2 Hz, Ph), 7.77 (d, 1H, J ¼ 7.2 Hz, Ph), 7.52 (s, 1H, Ph), 7.22 (m,
2H, Ph), 7.05 (m, 2H, Ph), 4.89 (t, 2H, J ¼ 7.2 Hz, CH2), 3.31 (t, 2H,
J ¼ 7.2 Hz, CH2). HRMS-ESI calcd for C17H15NOFCl: 268.1138
[M ꢂ Cl]þ, found 268.1140.
oxLDL
1
7e
7j
7k
7t
7u
Compound
Fig. 3. CD36 antagonistic activities of the active compounds in Sf9[hCD36] cells. OxLDL
was used as a positive control. The cellular uptake of DiI-AcLDL was determined in the
treatment of compounds (10 mg/mL). Presented are means and sds.
5.1.1.5. 7-Methoxy-2-(2-phenylethyl)isoquinolinium chloride (7d).
Yield: 43%; Brown oil; 1H NMR (DMSO-d6, ppm):
d 9.80 (s, 1H, 8-
CH), 8.65 (d, 1H, J ¼ 6.4 Hz, Ph), 8.49 (d, 1H, J ¼ 6.4 Hz, Ph), 8.26 (d,
1H, J ¼ 9.2 Hz, Ph), 7.88 (d, 1H, J ¼ 9.2 Hz, Ph), 7.72 (s, 1H, Ph),
7.28e7.21(m, 5H, Ph), 4.96 (t, 2H, J ¼ 7.6 Hz, CH2), 3.98 (s, 3H, OCH3),
3.53 (t, 2H, J ¼ 7.6 Hz, CH2). HRMS-ESI calcd for C18H18NOCl:
264.1388 [M ꢂ Cl]þ, found 264.1379.
5.1.1.2. 7-Hydroxy-2-(2-phenylethyl)isoquinolinium chloride (7a).
Yield: 51%; mp: 124e126 ꢀC (decomp); Orange solid; 1H NMR
(DMSO-d6, ppm):
d 11.50 (s, br, 1H, OH), 9.94 (s, 1H, 8-CH), 8.56 (d,
1H, J ¼ 6.8 Hz, Ph), 8.40 (d, 1H, J ¼ 6.8 Hz, Ph), 8.18 (d, 1H, J ¼ 8.8 Hz,
Ph), 7.80 (d, 1H, J ¼ 8.8 Hz, Ph), 7.63 (s, 1H, Ph), 7.28e7.19 (m, 5H,
Ph), 4.91 (t, 2H, J ¼ 7.2 Hz, CH2), 3.40 (t, 2H, J ¼ 7.2 Hz, CH2). 13C NMR
5.1.1.6. 8-Hydroxy-7-methoxy-2-(2-phenylethyl)isoquinolinium
(DMSO-d6, ppm):
d 172.7, 164.1, 162.2, 157.4, 138.6, 136.6, 132.2,
chloride (7e). Yield: 28%; mp: 78e80 ꢀC; Brown solid; 1H NMR
130.0, 128.7 (2), 128.6 (2), 126.9, 121.3, 114.5, 61.3, 33.2. HRMS-ESI
calcd for C17H16NOCl: 250.1232 [M ꢂ Cl]þ, found 250.1231.
(DMSO-d6, ppm):
d
9.95 (s, 1H, 8-CH), 8.35 (d, 1H, J ¼ 6.8 Hz, Ph),
8.07 (d, 1H, J ¼ 6.8 Hz, Ph), 7.83 (s, 1H, Ph), 7.78 (s, 1H, Ph), 7.31e7.24
(m, 5H, Ph), 6.98 (s, 1H, OH), 4.81 (t, 2H, J ¼ 6.4 Hz, CH2), 3.88 (s, 3H,
5.1.1.3. 7-Hydroxy-2-[2-(4-methoxyphenyl)ethyl]isoquinolinium
chloride (7b). Yield: 43%; mp: 118e120 ꢀC (decomp); Orange solid;
OCH3), 3.03 (t, 2H,
J
¼
6.4 Hz, CH2). HRMS-ESI calcd for
18H18NO2Cl: 280.1338 [M ꢂ Cl]þ, found 280.1357.
1H NMR (DMSO-d6, ppm):
d 9.10 (s, 1H, 8-CH), 7.96 (s, 2H, Ph), 7.50
C
Fig. 4. The Sf9[hCD36] cells were incubated with DiI-AcLDL (5
m
g/mL) and compounds 7t, 7e for 6 h, and then examined by confocal fluorescence microscopy (10ꢁmagnification).

Y.-X. Wang et al. / European Journal of Medicinal Chemistry 46 (2011) 1066e1073
1071
5.1.1.7. 8-Hydroxy-7-methoxy-2-[2-(4-methoxyphenyl)ethyl]iso-
J ¼ 6.8 Hz, Ph), 7.75 (s, 1H, Ph), 7.70 (s, 1H, Ph), 7.28e7.19 (m, 5H, Ph),
4.90 (t, 2H, J ¼ 6.4 Hz, CH2), 4.04 (s, 3H, OCH3), 3.97 (s, 3H, OCH3), 3.32
(t, 2H, J ¼ 6.4 Hz, CH2). HRMS-ESI calcd for C19H20NO2Cl: 294.1494
[M ꢂ Cl]þ, found 294.1485.
quinolinium chloride (7f). Yield: 46%; mp: 145e147 ꢀC (decomp);
Red solid; 1H NMR (DMSO-d6, ppm):
d 9.05 (s, 1H, 8-CH), 7.65 (d, 1H,
J ¼ 6.8 Hz, Ph), 7.51 (d, 1H, J ¼ 6.8 Hz, Ph), 7.26 (s, 1H, Ph), 7.18 (s, 1H,
Ph), 7.16 (s,1H, Ph), 7.14 (s,1H, Ph), 6.84(s,1H, Ph), 6.82(s,1H, Ph), 6.41
(s,1H, OH), 4.49 (t, 2H, J ¼ 7.2 Hz, CH2), 3.73 (s, 3H, OCH3), 3.69 (s, 3H,
OCH3), 3.08 (t, 2H, J ¼ 7.2 Hz, CH2). HRMS-ESI calcd for C19H20NO3Cl:
310.1443 [M ꢂ Cl]þ, found 310.1444.
5.1.1.15. 2-[2-(3-Fluorophenyl)ethyl]-6,7-dimethoxyisoquinolinium
chloride (7n). Yield: 44%; mp: 106e108 ꢀC (decomp); Orange solid;
1H NMR (DMSO-d6, ppm):
d
9.56 (s, 1H, 8-CH), 8.52 (d,1H, J ¼ 6.8 Hz,
Ph), 8.26 (d, 1H, J ¼ 6.8 Hz, Ph), 7.73 (s, 1H, Ph), 7.69 (s, 1H, Ph), 7.29
(dd, 1H, J ¼ 7.6 Hz, J ¼ 14.4 Hz, Ph), 7.15 (d, 1H, J ¼ 10.0 Hz, Ph), 7.06
(t,1H, J ¼ 8.8 Hz, Ph), 7.00 (d,1H, J ¼ 6.4 Hz, Ph), 4.89 (t, 2H, J ¼ 7.2 Hz,
CH2), 4.05(s, 3H, OCH3), 3.99(s, 3H, OCH3), 3.34(t, 2H, J ¼ 7.2 Hz, CH2).
5.1.1.8. 2-[2-(4-Fluorophenyl)ethyl]-8-hydroxy-7-methoxyisoquino-
linium chloride (7g). Yield: 32%; mp: 77e79 ꢀC (decomp); Dark red
solid; 1H NMR (DMSO-d6, ppm):
d 9.54 (s, 1H, 8-CH), 8.24 (d, 1H,
13C NMR (DMSO-d6, ppm):
d 160.9, 157.5, 152.4, 145.0, 139.3, 135.1,
J ¼ 6.8 Hz, Ph), 8.01 (d, 1H, J ¼ 6.8 Hz, Ph), 7.84 (s, 1H, Ph), 7.29 (m,
3H, Ph), 7.13 (m, 3H, Ph), 4.77 (t, 2H, J ¼ 7.2 Hz, CH2), 3.91 (s, 3H,
133.5, 130.5, 125.1, 123.6, 123.1, 115.8, 113.8, 107.0, 105.8, 60.4,
OCH3), 3.22 (t, 2H, J ¼ 7.2 Hz, CH2). 13C NMR (DMSO-d6, ppm):
d
56.8, 56.6, 36.0. HRMS-ESI calcd for
C19H19NO2FCl: 312.1340
[M ꢂ Cl]þ, found 312.1414.
162.4, 160.0, 147.5, 145.9, 132.7, 132.0, 131.0, 126.5, 123.3, 120.2,
119.6, 115.4 (2), 115.2 (2), 56.9, 55.6, 35.6. HRMS-ESI calcd for
C
18H17NO2FCl: 298.1243 [M ꢂ Cl]þ, found 298.1244.
5.1.1.16. 6,7-Dimethoxy-2-{2-[3-(trifluoromethyl)phenyl]ethyl}iso-
quinolinium chloride (7o). Yield: 51%; mp: 196e198 ꢀC (decomp);
5.1.1.9. 8-Hydroxy-7-methoxy-2-[2-(2-methylphenyl)ethyl]isoquino-
Pale white solid; 1H NMR (DMSO-d6, ppm):
d 9.65 (s,1H, 8-CH), 8.60
linium chloride (7h). Yield: 37%; mp: 261e263 ꢀC (decomp); Dark
(d,1H, J ¼ 6.8 Hz, Ph), 8.29 (d,1H, J ¼ 6.8 Hz, Ph), 7.76 (s,1H, Ph), 7.69
red solid; 1H NMR (DMSO-d6, ppm):
d 8.98 (s, 1H, 8-CH), 7.58 (d, 1H,
(s, 1H, Ph), 7.59e7.63 (m, 4H, Ph), 4.92 (t, 2H, J ¼ 7.2 Hz, CH2), 4.06
J ¼ 6.8 Hz, Ph), 7.45 (d, 1H, J ¼ 6.8 Hz, Ph), 7.20 (d, 1H, J ¼ 7.6 Hz, Ph),
7.11e7.14 (m, 5H, Ph), 6.32 (d, 1H, J ¼ 6.8 Hz, Ph), 4.47 (t, 2H,
J ¼ 7.6 Hz, CH2), 3.71 (s, 3H, OCH3), 3.31 (t, 2H, J ¼ 7.6 Hz, CH2), 2.28
(s, 3H, CH3). HRMS-ESI calcd for C19H20NO2Cl: 294.1494 [M ꢂ Cl]þ,
found 294.1499.
(s, 3H, OCH3), 3.99 (s, 3H, OCH3), 3.43 (t, 2H, J ¼ 7.2 Hz, CH2). 13
C
NMR (DMSO-d6, ppm):
d 157.6, 152.5, 145.2, 138.0, 137.2, 135.2,
133.6, 133.2,129.6, 129.1, 125.6, 123.7, 123.2, 118.0, 106.9, 105.8, 60.3,
56.8, 56.3, 36.0. HRMS-ESI calcd for C20H19NO2F3Cl: 362.1368
[M ꢂ Cl]þ, found 362.1353.
5.1.1.10. 7,8-Dimethoxy-2-(2-phenylethyl)isoquinolinium chloride (7i).
Yield: 58%; mp: 90e92 ꢀC; Yellow solid; 1H NMR (DMSO-d6, ppm):
5.1.1.17. 6,7-Dimethoxy-2-[2-(4-methoxyphenyl)ethyl]isoquinoli-
nium chloride (7p). Yield: 53%; mp: 122e124 ꢀC; Light yellow solid;
d
9.68 (s, 1H, 8-CH), 8.66 (d, 1H, J ¼ 7.0 Hz, Ph), 8.10 (d, 1H, J ¼ 7.0 Hz,
1H NMR (DMSO-d6, ppm):
d 9.56 (s, 1H, 8-CH), 8.51 (d, 1H,
Ph), 8.22 (d, 1H, J ¼ 9.0 Hz, Ph), 8.09 (d, 1H, J ¼ 9.0 Hz, Ph), 7.28e7.21
(m, 5H, Ph), 5.02 (t, 2H, J ¼ 7.5 Hz, CH2), 4.05 (s, 3H, OCH3), 3.97 (s, 3H,
OCH3), 3.43 (t, 2H, J ¼ 7.5 Hz, CH2). HRMS-ESI calcd for C19H20NO2Cl:
294.1494 [M ꢂ Cl]þ, found 294.1494.
J ¼ 6.4 Hz, Ph), 8.25 (d, 1H, J ¼ 6.4 Hz, Ph), 7.80 (s, 1H, Ph), 7.77
(s, 1H, Ph), 7.74 (s, 1H, Ph), 7.18 (m, 2H, Ph), 6.94 (s, 1H, Ph), 4.83
(t, 2H, J ¼ 6.4 Hz, CH2), 4.01 (s, 3H, OCH3), 3.94 (s, 3H, OCH3), 3.68
(s, 3H, OCH3), 3.24 (t, 2H, J ¼ 6.4 Hz, CH2). HRMS-ESI calcd for
C
20H22NO3Cl: 324.1560 [M ꢂ Cl]þ, found 324.1589.
5.1.1.11. 7,8-Dimethoxy-2-[2-(2-methylphenyl)ethyl]isoquinolinium
chloride (7j). Yield: 39%; Brown oil; 1H NMR (DMSO-d6, ppm):
5.1.1.18. 2-[2-(4-Chlorophenyl)ethyl]-6,7-dimethoxyisoquinolinium
d
9.60 (s, 1H, 8-CH), 8.61 (d, 1H, J ¼ 6.4 Hz, Ph), 8.49 (d, 1H,
chloride (7q). Yield: 42%; mp: 128e130 ꢀC (decomp); Bright yellow
J ¼ 6.8 Hz, Ph), 8.23 (d, 1H, J ¼ 9.2 Hz, Ph), 8.10 (d, 1H, J ¼ 8.8 Hz, Ph),
7.14 (m, 2H, Ph), 7.01 (m, 2H, Ph), 4.97 (t, 2H, J ¼ 7.2 Hz, CH2), 4.05
(s, 3H, OCH3), 3.94 (s, 3H, OCH3), 3.09 (t, 2H, J ¼ 7.2 Hz, CH2), 2.24
(s, 3H, CH3). HRMS-ESI calcd for C20H22NO2Cl: 309.1729
[M þ H ꢂ Cl]þ, found 309.1720.
solid; 1H NMR (DMSO-d6, ppm):
d 9.59 (s, 1H, 8-CH), 8.52 (d, 1H,
J ¼ 6.8 Hz, Ph), 8.26 (d, 1H, J ¼ 6.8 Hz, Ph), 7.74 (s, 1H, Ph), 7.69 (s, 1H,
Ph), 7.34 (d, 2H, J ¼ 8.4 Hz, Ph), 7.24 (d, 2H, J ¼ 8.4 Hz, Ph), 4.88
(t, 2H, J ¼ 7.2 Hz, CH2), 4.05 (s, 3H, OCH3), 3.99 (s, 3H, OCH3), 3.32
(t, 2H, J ¼ 7.2 Hz, CH2). 13C NMR (DMSO-d6, ppm):
d 157.5, 152.4,
145.2, 135.5, 135.2, 133.6, 131.6, 130.8 (2), 128.5 (2), 123.6, 123.1,
107.0, 105.8, 60.5, 56.8, 56.3, 35.6. HRMS-ESI calcd for
5.1.1.12. 2-[2-(3-Fluorophenyl)ethyl]-7,8-dimethoxyisoquinolinium
chloride (7k). Yield: 46%; Dark brown oil; 1H NMR (DMSO-d6,
C
19H19NO2Cl2: 328.1104 [M ꢂ Cl]þ, found 328.1106.
ppm):
d
9.75 (s, 1H, 8-CH), 8.61 (d, 1H, J ¼ 6.4 Hz, Ph), 8.50 (d, 1H,
J ¼ 6.4 Hz, Ph), 8.23 (d,1H, J ¼ 8.8 Hz, Ph), 8.09 (d,1H, J ¼ 8.8 Hz, Ph),
7.30 (dd, 1H, J ¼ 8.0 Hz, J ¼ 14.4 Hz, Ph), 7.18 (d, 1H, J ¼ 10.0 Hz, Ph),
7.05 (m, 2H, Ph), 5.01 (t, 2H, J ¼ 7.2 Hz, CH2), 4.05 (s, 3H, OCH3), 3.99
(s, 3H, OCH3), 3.35 (t, 2H, J ¼ 7.2 Hz, CH2). HRMS-ESI calcd for
5.1.1.19. 6-Hydroxy-7-methoxy-2-(2-phenylethyl)isoquinolinium
chloride (7r). Yield: 41%; mp: 224e226 ꢀC (decomp); Yellow solid;
1H NMR (DMSO-d6, ppm):
d 11.96 (s, br, 1H, OH), 9.43 (s, 1H, 8-CH),
19H19NO2FCl: 313.1478 [M þ H ꢂ Cl]þ, found 313.1465.
8.43 (d, 1H, J ¼ 6.8 Hz, Ph), 8.17 (d, 1H, J ¼ 6.8 Hz, Ph), 7.58 (s, 1H, Ph),
7.47 (s,1H, Ph), 7.29e7.19(m, 5H, Ph), 4.80 (t, 2H, J ¼ 7.6 Hz, CH2), 3.98
(s, 3H, OCH3), 3.25 (t, 2H, J ¼ 7.6 Hz, CH2). HRMS-ESI calcd for
C
5.1.1.13. 2-[2-(4-Chlorophenyl)ethyl]-7,8-dimethoxyisoquinolinium
chloride (7l). Yield: 43%; Yellow oil; 1H NMR (DMSO-d6, ppm):
9.73
C
18H18NO2Cl: 280.1338 [M ꢂ Cl]þ, found 280.1336.
d
(s,1H, 8-CH), 8.63(d,1H, J ¼ 6.4 Hz, Ph), 8.50 (d,1H, J ¼ 6.4 Hz, Ph), 8.23
(d,1H, J ¼ 8.8 Hz, Ph), 8.10 (d,1H, J ¼ 8.8 Hz, Ph), 7.35 (d, 2H, J ¼ 8.0 Hz,
Ph), 7.27 (d, 2H, J ¼ 8.8 Hz, Ph), 5.00 (t, 2H, J ¼ 7.2 Hz, CH2), 4.01 (s, 3H,
OCH3), 3.99 (s, 3H, OCH3), 3.36 (t, 2H, J ¼ 7.2 Hz, CH2). HRMS-ESI calcd
for C19H19NO2Cl2: 328.1104 [M ꢂ Cl]þ, found 328.1103.
5.1.1.20. 2-[2-(3-Chlorophenyl)ethyl]-6-hydroxy-7-methoxyisoqui-
nolinium chloride (7s). Yield: 45%; mp: 156e158 ꢀC (decomp);
Yellow-green solid; 1H NMR (DMSO-d6, ppm):
d 11.95 (s, br, 1H,
OH), 9.46 (s, 1H, 8-CH), 8.43 (d, 1H, J ¼ 6.8 Hz, Ph), 8.17 (d, 1H,
J ¼ 6.8 Hz, Ph), 7.70 (s, 1H, Ph), 7.48 (s, 1H, Ph), 7.43 (s, 1H, Ph), 7.38
(s, 1H, Ph), 7.31 (m, 2H, Ph), 4.42 (t, 2H, J ¼ 7.2 Hz, CH2), 3.97 (s, 3H,
5.1.1.14. 6,7-Dimethoxy-2-(2-phenylethyl)isoquinolinium chloride (7m).
1
Yield: 53%; mp: 124e126 ꢀC; Light yellow solid; H NMR (DMSO-d6,
OCH3), 3.09 (t, 2H,
C
J
¼
7.2 Hz, CH2). HRMS-ESI calcd for
18H17NO2Cl2: 314.0948 [M ꢂ Cl]þ, found 314.0957.
ppm):
d
9.67 (s, 1H, 8-CH), 8.58 (d, 1H, J ¼ 6.8 Hz, Ph), 8.26 (d, 1H,

1072
Y.-X. Wang et al. / European Journal of Medicinal Chemistry 46 (2011) 1066e1073
5.1.1.21. 6-Hydroxy-7-methoxy-2-[2-(4-methoxyphenyl)ethyl]iso-
7.03 (m, 4H, Ph), 4.68 (t, 2H, J ¼ 7.2 Hz, CH2), 3.97 (s, 3H, OCH3), 3.27
(t, 2H, J ¼ 7.2 Hz, CH2). HRMS-ESI calcd for C18H17NO3FCl: 314.0855
[M ꢂ Cl]þ, found 314.0842.
quinolinium chloride (7t). Yield: 48%; mp: 108e110 ꢀC (decomp);
Brown solid; 1H NMR (DMSO-d6, ppm):
d 8.80 (s, 1H, 8-CH), 7.91 (d,
1H, J ¼ 6.0 Hz, Ph), 7.49 (s, 2H, Ph), 7.19 (s, 1H, Ph), 7.12 (s, 1H, Ph),
7.10 (s, 1H, Ph), 6.84 (s, 1H, Ph), 6.82 (s, 1H, Ph), 6.72 (s, 1H, OH), 4.50
(t, 2H, J ¼ 7.2 Hz, CH2), 3.82 (s, 3H, OCH3), 3.72 (s, 3H, OCH3), 3.12 (t,
2H, J ¼ 7.2 Hz, CH2). HRMS-ESI calcd for C19H20NO3Cl: 311.1521
[M þ H ꢂ Cl]þ, found 311.1509.
5.2. CD36 antagonistic activity
5.2.1. CD36 antagonistic activities on the protein level
Each well of microplates (96-well) was coated with 100
mL
oxLDL (5
m
g/mL) at 4 ꢀC for 8e12 h. After being washed with
5.1.1.22. 2-[2-(4-Fluorophenyl)ethyl]-6-hydroxy-7-methoxyiso-
phosphate-buffered saline (PBS) buffer twice, the oxLDL-coated
wells were blocked with PBS buffer containing 1% bovine serum
albumin (BSA) for 1e2 h at 4 ꢀC. The wells were then washed with
PBST (PBS buffer with 0.1% Tween-20) buffer twice. After being
quinolinium chloride (7u). Yield: 37%; mp: 179e181 ꢀC (decomp);
Brown solid; 1H NMR (DMSO-d6, ppm):
d 9.26 (s,1H, 8-CH), 8.26 (d,
1H, J ¼ 6.4 Hz, Ph), 7.93 (d, 1H, J ¼ 6.4 Hz, Ph), 7.50 (s, 1H, Ph), 8.52
(dd,1H, J ¼ 6.8 Hz, 0.8 Hz, Ph), 8.41 (d,1H, J ¼ 6.8 Hz, Ph), 8.19 (d,1H,
J ¼ 6.8 Hz, Ph), 7.80 (dd, 1H, J ¼ 8.8 Hz, 2.4 Hz, Ph), 7.60 (d, 1H,
J ¼ 2.4 Hz, Ph), 7.26 (m, 2H, Ph), 7.10 (m, 2H, Ph), 4.88 (t, 2H,
J ¼ 7.2 Hz, CH2), 3.35 (t, 2H, J ¼ 7.2 Hz, CH2). HRMS-ESI calcd for
incubated with 100
m
L CD36 (30
m
g/mL) or vector control protein at
4 ꢀC for 1 h, 1
m
L study compounds (10
m
g/mL) or hexarelin (10 M)
m
was added, respectively. Following 2 h incubation, the plate was
washed and incubated with the mouse monoclonal antibody
against His-tag protein at a final dilution of 1:1250. The wells were
washed and incubated with HRP-conjugated goat antimouse IgG
(1:5000 dilution, 4 ꢀC, 1 h). Subsequently, after incubation with
C
18H17NO2FCl: 299.1322 [M þ H ꢂ Cl]þ, found 299.1300.
5.1.1.23. 2-[2-(4-Chlorophenyl)ethyl]-6-hydroxy-7-methoxyiso-
quinolinium chloride (7v). Yield 28%; mp: 235e237 ꢀC (decomp);
100
m
L TMB/H2O2 (mixed immediately before incubation by 1:1
Brown solid; 1H NMR (DMSO-d6, ppm):
d 8.68 (s, 1H, 8-CH), 7.80
[v/v]) for 45 min at 37 ꢀC, 100
mL HCl (1 M) was added to stop the
(d,1H, J ¼ 6.4 Hz, Ph), 7.34 (d, 2H, J ¼ 8.0 Hz, Ph), 7.23 (s,1H, Ph), 7.25
(d, 2H, J ¼ 8.0 Hz, Ph), 7.06 (s, 1H, Ph), 6.52 (s, 1H, Ph), 4.48 (t, 2H,
J ¼ 7.2 Hz, CH2), 3.80 (s, 3H, OCH3), 3.17 (t, 2H, J ¼ 7.2 Hz, CH2). HRMS-
ESI calcd for C18H17NO2Cl2: 314.0948 [M ꢂ Cl]þ, found 314.0964.
reaction. The optical density (OD) value of each well was recorded
using spectrophotometry with the microplate reader (Model 680
microplate reader, Bio-Rad) at 450 nm [17].
5.2.2. CD36 antagonistic activity on the cellular level [18]
5.1.2. General procedure for N-(2-arylethyl) isoquinolines analogs
(9aec)
Sf9 insect cells were grown and maintained in Grace’s medium
(Gibco/Invitrogen) supplemented with 10% heat-inactivated fetal
bovine serum (TNMFH medium, Hyclone) at 27 ꢀC. Sf9 cells were
mLofTNMFHmedium. After6h, the
cells were infected with 100 mL of recombinant or wild-type baculo-
To a suspension of anhydrous CuSO4 (1.8 equiv) and corre-
sponding hydrochlorate (5, 1.0 equiv) in anhydrous formic acid
(45 mL) was added 40% glyoxal solution (2.0 equiv) at 100 ꢀC. The
reaction mixture was stirred at 100 ꢀC for 1 h. Then the mixture was
filtered. The filtrate was concentrated in vacuo. The residue (8) was
acidified and purified to give 9, and the procedures were similar to
those of 7 series.
platedat6.0ꢁ105 cells/wellin100
viruses at a multiplicity of infection (MOI) in Grace’s medium for 1 h
and then refed with 200 L of TNMFH medium. Two days later, the
cells were washed once with Grace medium supplemented with 0.5%
(w/v) BSA (Sigma) and refed with 100 L of BSA. The compounds were
dissolved in DMSO and individually transferred (1.1 L) to the wells to
give a final concentration of 10
g/mL. After 1 h of incubation at 27 ꢀC,
DiI-AcLDL (2 g/mL, Biomedical Technologies) in 8 L of BSA was
m
m
m
5.1.2.1. 2-[2-(3-Chlorophenyl)ethyl]-1,6-dihydroxy-7-methox-
m
yisoquinolinium chloride (9a). Yield 23%; Brown oil; 1H NMR
m
m
(DMSO-d6, ppm): d 11.72 (s, br, 1H, OH), 9.04 (s, 1H, Ph), 7.85 (s, 1H,
Ph), 7.59 (s, 1H, Ph), 7.54 (s, 1H, Ph), 7.36 (s, 1H, Ph), 7.31 (m, 3H, Ph),
added. After 5 h, the fluorescence was measured using a fluorescence
microplate reader. Autofluorescence and quenching were tested
beforeremovingtheincubationmedium. Afterremovingthemedium,
7.16 (s, 1H, Ph), 4.79 (t, 2H, J ¼ 7.2 Hz, CH2), 3.96 (s, 3H, OCH3), 3.25
(t, 2H, J ¼ 7.2 Hz, CH2). 13C NMR (DMSO-d6, ppm):
d 156.3, 153.0,
the cells were fixed in 100
washed three times with 200
AcLDL was then determined in 100
m
L of 4% polyoxymethylene for 15 min and
L of PBS. The cellular uptake of DiI-
L of PBS. The active results were
151.0, 138.7, 136.4, 133.1, 130.3, 129.2, 127.3, 126.9, 123.3, 122.1, 117.0,
107.6, 104.5, 59.6, 55.3, 36.1. HRMS-ESI calcd for C18H17NO3Cl2:
330.0891 [M ꢂ Cl]þ, found 330.0897.
m
m
expressed as the inhibitory percentages of the total DiI fluorescence of
Sf9[hCD36] cells incubated in the absence of the compounds:
ꢀ
ꢁ.
ꢂ
ꢃ
Inhibition rate of total uptake ¼ Sf9½CD36ꢄcompoundꢂSf9½CD36ꢄOxꢂLDL
Sf9½CD36ꢄ ꢂ Sf9½CD36ꢄOxꢂLDL ꢁ 100%
5.1.2.2. 2-[2-(2-Methylphenyl)ethyl]-1,6-dihydroxy-7-methox-
5.2.3. CD36 antagonistic activity by fluorescence microscopy
yisoquinolinium chloride (9b). Yield 24%; Dark brown oil; 1H NMR
Receptor-mediated endocytosis of DiI-AcLDL by Sf9[hCD36]
(DMSO-d6, ppm):
d
8.78 (s, 1H, Ph), 7.70 (s, 1H, Ph), 7.59 (s, 1H, Ph),
cells untreated or treated with the compounds 7t or 7e (10 mg/mL)
7.53 (s, 1H, Ph), 7.13 (m, 3H, Ph), 7.05 (d, 2H, J ¼ 3.6 Hz, Ph), 4.68 (t,
2H, J ¼ 7.6 Hz, CH2), 4.01 (s, 3H, OCH3), 3.24 (t, 2H, J ¼ 7.6 Hz, CH2),
2.28 (s, 3H, CH3). HRMS-ESI calcd for C19H20NO3Cl: 310.1096
[M ꢂ Cl]þ, found 310.1104.
were detected by fluorescence microscopy. The cells were treated
as described for the Sf9[hCD36] HTS assay and then observed using
the IN Cell Analyzer 1000 (GE. Healthcare).
Acknowledgment
5.1.2.3. 2-[2-(3-Fluorophenyl)ethyl]-1,6-dihydroxy-7-methox-
yisoquinolinium chloride (9c). Yield: 28%; Dark brown oil; 1H NMR
This work was supported by the Research Funds of Peking Union
Medical College for Young Scientists and the National S&T Major
Special Project on Major New Drug Innovation (2009ZX09301-003)
(DMSO-d6, ppm):
d 8.52 (s, 1H, Ph), 7.61 (s, 2H, Ph), 7.44 (s, 1H, Ph),
7.28 (dd, 1H, J ¼ 14.4 Hz, J ¼ 7.2 Hz, Ph), 7.14 (d, 1H, J ¼ 10.0 Hz, Ph),

Y.-X. Wang et al. / European Journal of Medicinal Chemistry 46 (2011) 1066e1073
1073
[8] N. Ruiz-Velasco, A. Dominguez, M.A. Vega, Biochem. Pharmacol. 67 (2004)
303e313.
[9] C.A. Martin, E. Longman, C. Wooding, S.J. Hoosdally, S. Ali, T.J. Aitman,
D.A. Gutmann, P.S. Freemont, B. Byrne, K.J. Linton, Protein Sci. 16 (2007)
2531e2541.
[10] B. Sun, B.B. Boyanovsky, M.A. Connelly, P. Shridas, D.R. van der Westhuyzen,
N.R. Webb, J. Lipid Res. 48 (2007) 2560e2570.
[11] M. Febbraio, E.A. Podrez, J.D. Smith, D.P. Hajjar, S.L. Hazen, H.F. Hoff,
K. Sharma, R.L. Silverstein, J. Clin. Invest. 105 (2000) 1049e1056.
[12] M. Febbraio, E. Guy, R.L. Silverstein, Arterioscler. Thromb. Vasc. Biol. 24 (2004)
2333e2338.
[13] M. Febbraio, R.L. Silverstein, Int. J. Biochem. Cell Biol. 39 (2007) 2012e2030.
[14] P. Yang, D.-Q. Song, Y.-H. Li, W.-J. Kong, Y.-X. Wang, L.-M. Gao, S.-Y. Liu,
R.-Q. Cao, J.-D. Jiang, Bioorg. Med. Chem. Lett. 18 (2008) 4675e4677.
[15] Y.-H. Li, P. Yang, W.-J. Kong, Y.-X. Wang, C.-Q. Hu, Z.-Y. Zuo, Y.-M. Wang,
H. Gao, L.-M. Gao, Y.-C. Feng, N.-N. Du, Y. Liu, D.-Q. Song, J.-D. Jiang, J. Med.
Chem. 52 (2009) 492e501.
[16] Y.-X. Wang, Y.-P. Wang, H. Zhang, W.-J. Kong, Y.-H. Li, F. Liu, R.-M. Gao,
T. Liu, J.-D. Jiang, D.-Q. Song, Bioorg. Med. Chem. Lett. 19 (2009)
6004e6008.
[17] L. Wang, Y. Bao, Y. Yang, Y. Wu, X. Chen, S. Si, B. Hong, J. Biomol. Screen. 15
(2010) 239e250.
[18] Y.-N. Xu, J. Wang, Y. Bao, W. Jiang, L. Zuo, D.-Q. Song, B. Hong, S.-Y. Si, Anal.
Biochem. 400 (2010) 207e212.
and the National Natural Science Foundation of China (90913002
and 90813027).
References
[1] A.C. Nicholson, S. Frieda, A. Pearce, R.L. Silverstein, Arterioscler. Thromb. Vasc.
Biol. 15 (1995) 269e275.
[2] D. Calvo, D. Gómez-Coronado, Y. Suárez, M.A. Lasunción, M.A. Vega, J. Lipid
Res. 39 (1998) 777e788.
[3] E.A. Podrez, E. Poliakov, Z. Shen, R. Zhang, Y. Deng, M. Sun, P.J. Finton, L. Shan,
B. Gugiu, P.L. Fox, H.F. Hoff, R.G. Salomon, S.L. Hazen, J. Biol. Chem. 277 (2002)
38503e38516.
[4] K.J. Moore, V.V. Kunjathoor, S.L. Koehn, J.J. Manning, A.A. Tseng, J.M. Silver,
M. McKee, M.W. Freeman, J. Clin. Invest. 115 (2005) 2192e2201.
[5] J. Han, X. Zhou, T. Yokoyama, D.P. Hajjar, A.M. Gotto, A.C. Nicholson, Circula-
tion 109 (2004) 790e796.
[6] (a) B. Fuhrman, L. Koren, N. Volkova, S. Keidar, T. Hayek, M. Aviram, Athero-
sclerosis 164 (2002) 179e185;
(b) L. Puccetti, T. Sawamura, A.L. Pasqui, M. Pastorelli, A. Auteri, F. Bruni, Eur. J.
Clin. Invest. 35 (2005) 47e51.
[7] F. Bruni, A.L. Pasqui, M. Pastorelli, G. Bova, M. Cercignani, A. Palazzuoli,
T. Sawamura, W.R. Gioffre, A. Auteri, L. Puccetti, Clin. Appl. Thromb. Hemost.
11 (2005) 417e428.