Novel interleukin-5 inhibitors based on hydroxyethylaminomethyl-4H-chromen- 4-one scaffold

Article abstract of DOI:10.1016/j.bmc.2012.08.006

Hydroxyethylaminomethyl-4H-chromenones were previously discovered as fairly strong IL-5 inhibitor. For determination of detail structure activity relationship, N-substituted hydroxyethylaminomethylchromenones 4a-n were prepared and evaluated for their IL-

Full text of DOI:10.1016/j.bmc.2012.08.006

Bioorganic & Medicinal Chemistry 20 (2012) 5757–5762
Contents lists available at SciVerse ScienceDirect
Bioorganic & Medicinal Chemistry
journal homepage: www.elsevier.com/locate/bmc
Novel interleukin-5 inhibitors based on hydroxyethylaminomethyl-
4H-chromen-4-one scaffold
Cheonik Joo a, Eeda Venkateswararao a, Ki-Cheul Lee a, Vinay K. Sharma a, Min-Sik Kyung b,
Youngsoo Kim b, Sang-Hun Jung a,
⇑
a College of Pharmacy and Institute of Drug Research and Development, Chungnam National University, Daejeon 305-764, Republic of Korea
b College of Pharmacy, Chungbuk National University, Cheongu 361-763, Republic of Korea
a r t i c l e i n f o
a b s t r a c t
Article history:
Hydroxyethylaminomethyl-4H-chromenones were previously discovered as fairly strong IL-5 inhibitor.
For determination of detail structure activity relationship, N-substituted hydroxyethylaminomethyl-
chromenones 4a–n were prepared and evaluated for their IL-5 inhibitory activity. Shifting the hydrophobic
group to nitrogen from 1-position of hydroxyethylamino moiety of hydroxyethylaminomethyl-4H-
chromenones enhances the activity. The increment in bulkiness or hydrophobicity of alkyl side chain at
amino group increases the activity. The same level of activity of 5-(cyclohexylmethoxy)-3-(N-benzyl-2-
hydroxyethylaminomethyl)-4H-chromenone analogs regardless of hydrophobic or hydrophilic substitu-
ents at 4th position of phenyl ring might infer the existence of tunnel structure in the putative receptor
for accepting these side chains.
Received 18 July 2012
Revised 7 August 2012
Accepted 8 August 2012
Available online 16 August 2012
Keywords:
Chromenone analogs
Inhibitor
Interleukin-5
Eosinophils
Asthma
Ó 2012 Elsevier Ltd. All rights reserved.
1. Introduction
have been synthesized by the modification of Cys 66 residue in
IL-5 and reported as its antagonists.9 Later, Min et al. had identified
Asthma is the common chronic inflammatory disease of the
airways characterized by reversible airflow blockade and broncho-
spasm, accompanied with symptoms like coughing, wheezing,
shortness of breath or rapid breathing, and chest tightness.1 The
occurrence of asthma has amplified considerably since 1970s.2
naturally occurring sophoricoside (1a, Fig. 1) and its analogs for
their IL-5 inhibitory activity.10 In addition, sophoricoside has also
been identified as differential inhibitor of IL-3 and GM-CSF.11 As
sophoricoside showed promising IL-5 inhibitory activity, various
isoflavonoid analogs of sophoricoside12,13 and chalcone deriva-
tives14,15 were investigated as potent inhibitors of IL-5. For the
SAR studies of these sophoricoside analogs,12 we initially observed
that not only the planar chromen-4-one ring but also phenolic
hydroxyl group at para position of ring B is essential for their
IL-5 inhibitory activity.12,13 In addition, the introduction of hydro-
phobic moiety such as cyclohexylmethoxy group at 5-position of
isoflavone (1b and 1d, Fig. 1) is also required for the good inhibi-
tory activity. Then the role of ring B was explored and accordingly
a number of novel chromenone analogs with insertion of methy-
lene between phenyl and chromenone (2a, 98% inhibition at
Asthma is linked with intrusion of
T cells and eosinophils,
increased levels of pro-inflammatory cytokines such as interleu-
kin-4 (IL-4), IL-5 and IL-13, and shedding of bronchial epithelial
cells (ECs).3 The eosinophils are the major effector cells in allergic
inflammation and are present in increased numbers in the circula-
tion and sputum depending upon the severity of asthma.4 IL-5 is
the primary cytokine which is involved in the production, differen-
tiation, maturation and activation of the eosinophils.5 It is present
in increased amounts in the mucosa of asthmatic airways and the
expression of IL-5 mRNA is directly related to seriousness of the
disease.6,7 Moreover, the inhalation of IL-5 increases the eosinophil
percentage in induced sputum and boosts airway hyper respon-
siveness in asthmatics.8 Thus targeting IL-5 will be quite effective
in the treatment of allergic diseases like asthma.
30
at 30
l
M, IC50 = 3.0
l
M, Fig. 1) or without ring B (2b, 85% inhibition
l
lM, IC50 = 7.6
M, Fig. 1) were prepared and evaluated.16
These variations well retained the level of activity of isoflavones.16
Along this line, novel 5-(cyclohexylmethoxy)-3-(1-alkyl-2-hydrox-
yethylaminomethyl)chromones such as 3a–d17 were investigated
as inhibitors of IL-5 (Fig. 1). Although the chromenone 3a with
2-hydroxyethylaminomethyl group did not show any activity,
introduction of bulky hydrophobic group at 1-position of
2-hydroxyethylamino moiety (3b–d) exhibited fairly strong
For decades, a number of small organic compounds have been
reported for the inhibition of IL-5. Among them isothiazolones
⇑
Corresponding author. Tel.: +82 42 821 5939; fax:+82 42 823 6566.
E-mail address: jungshh@cnu.ac.kr (S.-H. Jung).
0968-0896/$ - see front matter Ó 2012 Elsevier Ltd. All rights reserved.
http://dx.doi.org/10.1016/j.bmc.2012.08.006

5758
C. Joo et al. / Bioorg. Med. Chem. 20 (2012) 5757–5762
R3
R1
O
O
O
O
O
R1
R2
1a: Sophoricoside R1,R2 = OH, R3 = OGlu
2a, R1 = C6H5OH
1b
: R1 = benzyloxy, R2 = H, R3 = OH
2b
, R1 = OH
1c: R1 = H, R2 = benzyloxy, R3 = OH
1d: R1 = cyclohexylmethoxy, R2 =H, R3 = OH
O
O
O
R
O
O
OH
OH
N
H
N
R
O
3a-d = substituents are located in Table 1
4a n,
-
R = substituents are located in Table 1
Figure 1. Interleukin-5 inhibitors 1, 2, 3 and amino alcohol chromone analogs 4.
Table 1
reported the design and synthesis of a number of N-substituted
hydroxyethylaminomethylchromenone derivatives (4a–n) and
tested for their IL-5 inhibitory activity.
Structures and C logP values of 4(a–n)
Compd. no.
R
C logPa Compd. no.
R
C logPa
2. Chemistry
3a17
H
2.9143 4f
5.2791
The synthesis of the desired compounds 4a–n was accom-
plished with reductive amination of 516 as outlined in Scheme 1.
Accordingly, 3-formylchromone 516 in 1,2-dichloroethane was
treated with secondary amine 6a–n and sodium triacetoxyborohy-
dride at ambient temperature for 12 h. After purification with flash
column chromatography, compounds 4a–n were obtained with
moderate yields. For the reductive amination, treatment of 5 and
secondary amines 6 with sodium borohydride or sodium cyano-
borohydride in ethanol at reflux did not undergo reaction unlike
reductive amination with primary amines.16 This might be steri-
cally more congested in the iminium intermediate 7 compared to
imines formed from primary amine.18 All these synthesized
compounds (Table 1) were characterized by physical and spectral
analysis data that confirmed their assigned structures.
3b17
3c17
3d17
4a
3.9589 4g
5.8733 4h
4.7913 4i
3.4557 4j
5.4867
6.1057
5.1717
5.6707
–CH3
4b
4c
–CH2CH3
3.9847 4k
4.5137 4l
4.5047
5.0907
OH
O
3. Conformational analysis and alignment
Molecular model of the compounds 3d17 and 4i were con-
structed using SYBYLÒ-X1.3 program package (Tripos Associates
Inc.)19 and their geometry were optimized (Powell conjugate
–
(CH2)2CH3
–
4d
4e
5.0427 4m
4.2937 4n
5.8847
3.6747
(CH2)3CH3
O
O
O
O
Cl
R
OH
O
O
O
N
H
OH
HN
R
+
H
–CH(CH3)2
N
6a-o
5
7
a
C logP values were calculated by Chem. draw version 9.0.
a
activity (Table 1). Thus these results indicated that the ring B of
isoflavone 1a acts as a simple linker between the chromenone
and the hydroxyl function.
As these hydroxyethylaminomethylchromones 3b–d ( Fig. 1,
Table 1) showed fairly good inhibitory activity against IL-5, more
detailed structure–activity relationship studies are needed to get
the potential drug candidate. Therefore, here in this article we have
O
O
O
OH
N
R
4a-n
Scheme 1. Synthesis of choromone analogs 4(a–n). Reagents and conditions: (a)
NaBH(OAc)3, 1,2-dichloroethane, rt. Note = substituents are located in Table 1.

C. Joo et al. / Bioorg. Med. Chem. 20 (2012) 5757–5762
5759
gradient minimization, termination at a gradient of 0.0005 kcal/
mol) using the Tripos standard force field20 and Gasteiger–Hückel
atomic partial charges.21 The 3D structures of the analyzed com-
pounds were aligned according to a chromenone template, which
was assumed to be a bioactive conformation.
indicated that the bulkier cyclohexyl have better activity than
the phenyl one. Thus the bulky hydrophobic group in this region
should be more important than the shape or planarity of the
phenyl ring.
Insertion of a methyl unit between amino group and bulky
substituents slightly decreases the activity as in cyclohexylmethyl
analog 4h (94.7% inhibition at 30
6.1057) and benzyl 4i (94.8% inhibition at 30
l
M, IC50 = 12.4
l
M, C logP =
4. Pharmacology
lM, IC50 = 16.1
lM,
C logP = 5.1717) compared to the corresponding 4f–g. Though
these derivatives showed slightly less inhibition still they are
potent inhibitors of IL-5, which further approves the significance
of hydrophobicity in this region.
In next set of experiment, the effect of substituents at 4th
position of the phenyl ring of 4i was investigated. Since phenolic
hydroxyl group or electron donating group at 4-position of ring B
of 1a plays an important role for their IL-5 inhibitory activity,
Inhibitory activity of the chromenone analogs (4a–n) against
IL-5 was evaluated using the IL-5-dependent pro-B Y16 cell line
according to previously reported procedure.22 The cells were incu-
bated with 3 units/mL mIL-5 for 48 h, in the presence or absence of
sample, and then measured cell metabolism as an index of prolif-
eration, using 2-(4-iodophenyl)-3-(nitrophenyl)-5-(2,4-disulph-
ophenyl)-2H tetrazolium sodium salt (WST-1). Data were
collected from three independent experiments. The effect of test
compounds on the IL-5 bioassay is represented as per cent inhibi-
methyl (4j,94.3% inhibition at 30
5.6707), hydroxyl (4k, 93.7% inhibition at 30
C logP = 4.5047), methoxy (4l, 94.1% inhibition at 30
IC50 = 9.0
at 30 M, IC50 = 10.3
l
M, IC50 = 9.4
lM, C logP =
lM, IC50 = 9.1
lM,
tion at 30 lM samples and IC50 values were calculated (Table 2).
lM,
l
M, C logP = 5.0907) and chloro (4m, 93.4% inhibition
5. Results and discussion
l
l
M, C logP = 5.8847) substituents were intro-
duced at 4th position of the phenyl ring of 4i. The results indicated
that all these derivatives have potent inhibitory activity regardless
of hydrophobic or hydrophilic nature of these substituents at 4th
position of phenyl ring of 4i. These might infer the existence of tun-
nel structure in the putative receptor for accepting these side
chains. This can be validated by pyridine-4-methyl substituent as
For determining more detail structure–activity relationship
studies of 3-(2-hydroxyethylaminomethyl)chromones, we de-
signed and synthesized a number of analogs of 3a by introduction
of bulky substituents at amino group of 3a and studied them for
their IL-5 inhibitory activity. (Table 2)
In the first set of experiment, methyl analog 4a (56.0% inhibi-
shown in analog 4n (94% inhibition at 30
C logP = 3.6747).
lM, IC50 = 14.2 lM,
tion at 30
inhibitory activity as compared to 3a (13.2% inhibition at 30
IC50 >50
M).17 This suggests that the hydrophobic substitution
lM, IC50 = 30.3
lM, C logP = 3.4557) showed better
lM,
Comparison of the activity (Table 1) of 4f, 4h and 4i to those of
3b, 3c and 3d, respectively, revealed the potentiation of the activity
in compounds 4. This obviously implies that moving the side chain
towards chromenone ring enhances the activity.
l
on amino group of 3a increases the activity of these chromenones.
To further confirm the optimum size of substituent at amino group
of 3a, the ethyl group was introduced. As a result the activity im-
To further investigate the detailed structural requirements for
the potent IL-5 inhibitor we compared the structural sketches of
the compound 3d17 and 4i and observed a dramatic difference in
the region of side chain at 3-position of chromenone scaffold (
Fig. 2). The dihedral angles (\C1–C2–N3–C4 and \C2–N3–C4–C5) of
compound 3d are 198.9°and 161.1°, respectively (Table 3). This
indicates that the hydroxyethylaminomethyl moiety of 3d is
stretched away from chromenone ring. In addition, the distance
from C-1 carbon to hydroxyl group oxygen (6.007 Å, Fig. 2) also
confirms this stretch conformation. Meanwhile the corresponding
angles (\C1–C2–N3–C4 = 307.3° and \C2–N3–C4–C5 = 99.7°, Table
3) of 4i depict that hydroxyl group of hydroxyethylaminomethyl
moiety of 4i is located nearly at right angle position in chromenone
ring plane. The much shorter distance from C-1 carbon to oxygen
of hydroxyl group (4.469 Å, Fig. 2) in 4i than in 3d also implies
the folded conformation of hydroxyethylaminomethyl moiety.
Such conformational change might cause the enhancement of the
activity of analogs 4 compared to those of the corresponding com-
pounds 3. Therefore, the folded conformation as shown in 4i could
proved in analog 4b (79.2% inhibition at 30 lM, IC50 = 19.5 lM,
C logP = 3.9847). This outcome supports that the hydrophobicity
or bulkiness at amino alcohol plays a critical role in inhibitory
activity against IL-5. To prove our point the chain length and bulk-
iness at this position was further increased. The propyl analog 4c
(93.7% inhibition at 30
lM, IC50 = 15.4
lM, C logP = 4.5137) and
butyl analog 4d (94.0% inhibition at 30
l
M, IC50 = 9.2 M,
l
C logP = 5.0427) confirmed our viewpoint that hydrophobicity or
bulkiness is important for the activity. The bulkier isopropyl analog
4e (90.2% inhibition at 30 lM, IC50 = 10.2 lM, C logP = 4.2937)
maintained the activity. Considering C logP values of 4a–d, it was
observed that increment of hydrophobicity by increasing bulky ali-
phatic groups or linear alkyl chain is well correlated with the
activity.
In another set of experiment the planar phenyl derivatives 4f
(94.4% inhibition at 30
lM, IC50 = 14.3
lM, C logP = 5.2791) and
bulky cyclohexyl 4g (94.5% inhibition at 30
l
M, IC50 = 9 M,
l
C logP = 5.4867) on nitrogen of 3a were introduced. The results
Table 2
Interleukin-5 inhibitory activity of 4(a–n)
% Inhibitiona at 30 (
l
M)
IC50
(lM)
Compd. no.
% Inhibitiona at 30 (
l
M)
IC50
(lM)
a
Compd. no.
3a17
13.2
88.0
93.4
72.4
56.0
79.2
93.7
94.0
90.2
79.1
>50
4f
4g
4h
4i
4j
4k
4l
4m
94.4
94.5
94.7
94.8
94.3
93.7
94.1
93.4
94.0
55.3
14.3
9.0
12.4
16.1
9.4
9.1
9.0
10.3
14.2
27.1
3b17
18.5
17.3
25.7
30.3
19.5
15.4
9.2
3c17
3d17
4a
4b
4c
4d
4e
10.2
10.6
4n
Sophoricoside
Budesonide
a
% Inhibition and IC50 values are taken as a mean from 3 experiments.

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C. Joo et al. / Bioorg. Med. Chem. 20 (2012) 5757–5762
standard procedures prior to use.23 Thin layer chromatography
8
10
12
was performed on E Mercksilica gel GF-254 precoated plates
and the identification was done with UV light and colorization
with spray 10% phosphomolybdic acid followed by heating. Flash
column chromatography was performed with E Merck silica gel
(230–400 mesh). Infra red spectrum was recorded by using sam-
ple as such on FT-IR spectrum with Nicolet—380 models. NMR
spectra were measured against the peak of tetramethylsilane by
JEOL JNM-EX90 NMR (89.45 MHz) and Varain Unity Inova 400
NMR (400 MHz) spectrometers. High resolution mass spectra
(HRMS) were measured by using Shimadzu LCMS-IT-TOF
spectrometer.
12
10
11
9
11
9
O
O
O
O
O
O
7
6
OH
6
3
3
1
OH
1
5
4
2
4
2
N
N
5
H
7
8
3d17
4i
7.1.1. Procedure for the preparation of compound 4a–n
To a solution of 3-formylchromone 5 (1 equiv) in 1,2-dichloro-
ethane was added secondary amine 6a–o (1.2 equiv) and sodium
triacetoxyborohydride (1.5 equiv). After stirring at room tempera-
ture for 12 h, the reaction mixture was quenched with H2O and ex-
tracted with CH2Cl2. The combined organic layers were washed
with brine, dried over Na2SO4, and concentrated in vacuo. The res-
idue was purified by flash silica gel chromatography to obtained
4a–n.
Figure 2. Alignment of compound 3d17 (18.0114 kcals/mol) and 4i (17.5547 kcals/
mol). Cyan color (3d17), Green color (4i).
Table 3
Torsion angle(°) of compounds 3d17 and 4i
Compound 3d17
Compound 4i
\C1–C2–N3–C4
\C2–N3–C4–C5
\N3–C4–C5–C6
\C2–N3–C4–C7
\N3–C4–C7–O8
\C9–O10–C11–C12
198.9°
161.1°
189.8°
284.8°
178.3°
56.2°
\C1–C2–N3–C4
\C2–N3–C4–C5
\N3–C4–C5–C6
\C1–C2–N3–C7
\C2–N3–C7–O8
\C9–O10–C11–C12
307.3°
99.7°
178.7°
102.0°
157.5°
58.3°
7.1.1.1.
amino)methyl)-4H-chromen-4-one (4a).
oil; Rf: 0.32 (MeOH:CH2Cl2 = 1:15); IR (KBr) 3407, 2920, 1743,
1650, 1269, 1065 cmÀ1 1H NMR (CDCl3) d 1.05–2.05 (m, 11H),
2.30 (s, 3H), 2.64 (t, J = 5.2 Hz, 2H), 3.43 (s, 2H), 3.71 (t, J = 5.2 Hz,
2H), 3.85 (d, J = 6.0 Hz, 2H), 6.76 (d, J = 8.0 Hz, 1H), 6.96 (d,
J = 8.4 Hz, 1H), 7.49 (t, J = 8.4 Hz, 1H), 7.75 (s, 1H); 13C NMR (CDCl3)
d 177.36, 159.86, 158.63, 152.44, 133.72, 121.39, 114.86, 109.62,
107.22, 74.82, 58.74, 58.70, 51.39, 42.12, 37.35, 29.75, 26.46,
5-(Cyclohexylmethoxy)-3-(((2-hydroxyethyl)(methyl)
Yield 37%; yellow
;
C1–12 and N3 atoms of 3d and 4i are mentioned in Figure 2.
be much closer to the effective conformation for binding to the
putative receptor.
25.173; HRMS: calcd. for
345.1935.
C20H27NO4: m/z 345.1940, found:
6. Conclusion
7.1.1.2.
no)methyl)-4H-chromen-4-one (4b).
Rf: 0.33 (MeOH:CH2Cl2 = 1:15); IR (KBr) 3442, 2923, 1656, 1269,
1068 cmÀ1 1H NMR (CDCl3) d 1.05 (t, J = 6.4 Hz, 3H), 1.09–2.05
(m, 11H), 2.61 (q, J = 6.8 Hz, 2H), 2.69 (t, J = 5.0 Hz, 2H), 3.53 (s,
2H), 3.67 (t, J = 5.4 Hz, 2H), 3.86 (d, J = 6.4 Hz, 2H), 6.76 (d,
J = 8.4 Hz, 1H), 6.96 (d, J = 8.8 Hz, 1H), 7.49 (t, J = 8.4 Hz, 1H), 7.78
(s, 1H); 13C NMR (CDCl3) d 177.29, 159.80, 158.57, 153.29,
133.80, 120.87, 114.74, 109.70, 107.32, 74.85, 58.65, 54.80, 48.01,
47.85, 37.31, 29.73, 26.44, 25.71, 10.82; HRMS: calcd. for
5-(Cyclohexylmethoxy)-3-((ethyl(2-hydroxyethyl)ami
For determination of detailed structure activity relationship of
hydroxyethylaminomethylchromenones as IL-5 inhibitor, N-
substituted analogs 4a–n were prepared and evaluated for their
IL-5 inhibitory activity. Among these derivatives compounds 4d,
4g and 4j–l showed the most potent inhibitory activity. The results
indicated that increment in bulkiness or hydrophobicity at amino
group increases the activity. The same level of activity of benzyl
analogs 4i–m regardless of hydrophobic or hydrophilic substitu-
ents at para position of phenyl ring of 4i might conclude the exis-
tence of tunnel structure in the putative receptor for accepting
these side chains. Based on the conformational analysis, introduc-
tion of hydrophobic group on nitrogen seems to enforce the more
effective conformation of hydroxyethylaminomethyl side chain of
analogs 4 and thus increase in activity compared to analogs 3.
Thus the structural requirement of these chromenone analogs
possessing the inhibitory activity against IL-5 could be summa-
rized as: (i) importance of hydrophobic group, such as cyclohexyl-
methoxy at position 5 of ring A, (ii) planarity of the chromen-4-one
ring, (iii) hydrophobicity in the ring B region, especially bulky and
hydrophobic substituents on nitrogen of hydroxyethylamino
moiety as the critical motif for IL-5 inhibitory activity of 3-(hydrox-
yethylaminomethyl)-4H-chromenones.
Yield 42%; yellow oil;
;
C21H29NO4: m/z 359.2097, found: 359.2090.
7.1.1.3. 5-(Cyclohexylmethoxy)-3-(((2-hydroxyethyl)(propyl)am
ino)methyl)-4H-chromen-4-one (4c). Yield 31%; yellow oil;
Rf: 0.34 (MeOH:CH2Cl2 = 1:15); IR (KBr) 3390, 2922, 1734, 1657,
1268, 1061 cmÀ1 1H NMR (CDCl3) d 0.85 (t, J = 7.4 Hz, 3H), 1.05–
;
2.05 (m, 13H), 2.48 (t, J = 7.4 Hz, 2H), 2.69 (t, J = 5.0 Hz, 2H), 3.54
(s, 2H), 3.67 (t, J = 5.2 Hz, 2H), 3.86 (d, J = 6.0 Hz, 2H), 6.76 (d,
J = 8.4 Hz, 1H), 6.96 (d, J = 8.0 Hz, 1H), 7.49 (t, J = 8.4 Hz, 1H), 7.80
(s, 1H); 13C NMR (CDCl3) d 177.45, 159.82, 158.60, 152.04,
133.59, 122.24, 114.82, 109.62, 107.19, 74.83, 59.17, 56.01, 55.61,
48.86, 37.35, 29.72, 26.44, 25.72, 19.80, 11.60; HRMS: calcd. for
C22H31NO4: m/z 373.2253, found: 373.2248.
7. Materials and methods
7.1. Chemistry
7.1.1.4. 3-((Butyl(2-hydroxyethyl)amino)methyl)-5-(cyclohexyl-
methoxy)-4H-chromen-4-one (4d). Yield 39%; yellow oil; Rf:
0.34 (MeOH:CH2Cl2 = 1:15); IR (KBr) 3446, 2922, 1732, 1657, 1268,
1061 cmÀ1; 1H NMR (CDCl3) d 0.87 (t, J = 7.4 Hz, 3H), 1.09–2.21 (m,
15H), 2.51 (t, J = 7.4 Hz, 2H), 2.68 (t, J = 5.2 Hz, 2H), 3.53 (s, 2H),
3.67 (t, J = 5.4 Hz, 2H), 3.86 (d, J = 6.0 Hz, 2H), 6.76 (d, J = 8.4 Hz,
1H), 6.96 (d, J = 8.4 Hz, 1H), 7.49 (t, J = 8.4 Hz, 1H), 7.79 (s, 1H);
Melting points were determined on Electro thermal 1A 9100
MK2 apparatus and are uncorrected. All commercial chemicals
were used as obtained and all solvents were purified by the

C. Joo et al. / Bioorg. Med. Chem. 20 (2012) 5757–5762
5761
13C NMR (CDCl3) d 177.44, 159.82, 158.60, 152.14, 133.61, 122.14,
114.81, 109.65, 107.21, 74.84, 59.12, 55.59, 53.84, 48.84, 37.37,
29.73, 28.72, 26.46, 25.73, 20.39, 13.88; HRMS: calcd. for
7.1.1.10. 5-(Cyclohexylmethoxy)-3-(((2-hydroxyethyl)(4-meth-
ylbenzyl)amino)methyl)-4H-chromen-4-one (4j). Yield
37%; yellow solid; Rf: 0.21 (MeOH:CH2Cl2 = 1:30); IR (KBr) 3479,
2904, 1658, 1280, 1066 cmÀ1 1H NMR (CDCl3) d 1.07–2.06 (m,
C23H33NO4: m/z 387.2410, found: 387.2404.
;
11H), 2.29 (s, 3H), 2.68 (t, J = 5.4 Hz, 2H), 3.55 (s, 2H), 3.62 (s,
2H), 3.67 (t, J = 5.2 Hz, 2H), 3.87 (d, J = 6.0 Hz, 2H), 6.76 (d,
J = 8.4 Hz, 1H), 6.93 (d, J = 8.4 Hz, 1H), 7.07 (d,, J = 7.6 Hz, 2H),
7.17 (d,, J = 8.0 Hz, 2H), 7.22 (s, 4H), 7.48 (t, J = 8.4 Hz, 1H), 7.75
(s, 1H); 13C NMR (CDCl3) d 177.51, 159.82, 158.56, 151.92,
136.69, 135.79, 133.55, 129.06, 128.73, 122.41, 114.89, 109.57,
107.21, 74.86, 59.43, 58.27, 55.40, 48.65, 37.37, 29.72, 26.46,
25.75, 20.97; HRMS: calcd. for C27H33NO4: m/z 435.2410, found:
435.2405.
7.1.1.5. 5-(Cyclohexylmethoxy)-3-(((2-hydroxyethyl)(isopropyl)
amino)methyl)-4H-chromen-4-one (4e). Yield 41%; yellow
oil; Rf: 0.33 (MeOH:CH2Cl2 = 1:15); IR (KBr) 3478, 2922, 1737,
1650, 1267, 1061 cmÀ1 1H NMR (CDCl3) d 1.05 (d, J = 6.4 Hz, 6H),
1.07–2.05 (m, 11H), 2.65 (t, J = 4.8 Hz, 2H), 2.69 (m, 1H), 3.56 (s,
2H), 3.60 (t, J = 5.2 Hz, 2H), 3.86 (d, J = 6.0 Hz, 2H), 6.76 (d,
J = 8.4 Hz, 1H), 6.96 (d, J = 8.0 Hz, 1H), 7.49 (t, J = 8.4 Hz, 1H), 7.80
(s, 1H); 13C NMR (CDCl3) d 177.67, 159.92, 158.74, 152.17,
133.70, 120.96, 122.98, 114.83, 109.80, 107.24, 74.96, 59.46,
50.62, 50.32, 45.59, 37.49, 29.88, 26.58, 25.85, 17.88; HRMS: calcd.
for C22H31NO4: m/z 373.2253, found: 373.2249.
;
7.1.1.11. 5-(Cyclohexylmethoxy)-3-(((4-hydroxybenzyl)(2-hydr
oxyethyl)amino)methyl)-4H-chromen-4-one
32%; yellow solid; Rf: 0.37 (MeOH:CH2Cl2 = 1:15); IR (KBr) 3470,
2928, 1733, 1650, 1272, 1066 cmÀ1 1H NMR (CDCl3) d 1.07–2.02
(4k).
Yield
7.1.1.6.
amino)methyl)-4H-chromen-4-one (4f).
solid; Rf: 0.27 (MeOH:CH2Cl2 = 1:30); IR (KBr) 3447, 2904, 1644,
1273, 1081 cmÀ1 1H NMR (CDCl3) d 1.06–2.07 (m, 11H), 2.69 (m,
5-(Cyclohexylmethoxy)-3-(((2-hydroxyethyl)(phenyl)
;
Yield 35%; yellow
(m, 11H), 2.65 (t, J = 5.0 Hz, 2H), 3.53 (s, 2H), 3.57 (s, 2H), 3.68 (t,
J = 5.2 Hz, 2H), 3.86 (d, J = 6.4 Hz, 2H), 6.71 (d, J = 8.4 Hz, 2H),
6.77 (d, J = 8.0 Hz, 1H), 6.94 (d, J = 8.4 Hz, 1H), 7.11 (d, J = 8.0 Hz,
2H), 7.49 (t, J = 8.4 Hz, 1H), 7.75 (s, 1H); 13C NMR (CDCl3+DMSO-
d6) d 177.58, 159.73, 158.60, 156.44, 152.26, 133.65, 129.97,
129.52, 122.64, 115.36, 114.77, 109.74, 107.24, 74.80, 59.60,
58.22, 55.67, 48.71, 37.42, 29.72, 26.47, 25.78; HRMS: calcd. for
;
2H), 3.59 (t, J = 5.6 Hz, 2H), 3.84–3.91 (m, 4H), 4.49 (s, 2H), 6.71–
6.78 (m, 4H), 6.92 (d, J = 8.4 Hz, 1H), 7.19 (d, J = 7.2 Hz, 1H), 7.21
(d, J = 7.2 Hz, 1H), 7.46–7.51 (m, 2H); 13C NMR (CDCl3) d 177.97,
159.67, 158.70, 150.95, 148.11, 133.67, 129.41, 120.39, 117.27,
114.49, 112.81, 109.86, 106.93, 74.75, 60.36, 53.74, 47.48, 37.40,
29.79, 26.46, 25.74; HRMS: calcd. for C25H29NO4: m/z 407.2097,
found: 407.2091.
C26H31NO5: m/z 437.2202, found: 437.2196.
7.1.1.12. 5-(Cyclohexylmethoxy)-3-(((2-hydroxyethyl)(4-metho
xybenzyl)amino)methyl)-4H-chromen-4-one (4l). Yield
34%; yellow solid; Rf: 0.39 (MeOH:CH2Cl2 = 1:15); IR (KBr) 3452,
2918, 1734, 1651, 1278, 1067 cmÀ1 1H NMR (CDCl3) d 1.07–2.02
7.1.1.7. 3-((Cyclohexyl(2-hydroxyethyl)amino)methyl)-5-(cyclo-
hexylmethoxy)-4H-chromen-4-one (4g).
solid; Rf: 0.29 (MeOH:CH2Cl2 = 1:30); IR (KBr) 3444, 2934, 1735,
1651, 1274, 1061 cmÀ1 1H NMR (CDCl3) d 1.03–2.09 (m, 21H),
Yield 32%; yellow
;
(m, 11H), 2.67 (t, J = 5.4 Hz, 2H), 3.54 (s, 2H), 3.60 (s, 2H), 3.67 (t,
J = 5.2 Hz, 2H), 3.76 (s, 3H), 3.87 (d, J = 6.0 Hz, 2H), 6.76 (d,
J = 8.0 Hz, 1H), 6.81 (d, J = 8.4 Hz, 2H), 6.93 (d, J = 8.4 Hz, 1H),
7.20 (d, J = 8.4 Hz, 2H), 7.48 (t, J = 8.4 Hz, 1H), 7.74 (s, 1H); 13C
NMR (CDCl3) d 177.51, 159.84, 158.74, 158.57, 151.93, 133.58,
130.86, 129.93, 122.42, 114.90, 113.74, 109.58, 107.23, 74.87,
59.41, 57.93, 55.32, 55.18, 48.62, 37.38, 29.73, 26.46, 25.75; HRMS:
calcd. for C27H33NO5: m/z 451.2359, found: 451.2355.
;
2.70 (t, J = 5.0 Hz, 2H), 3.57 (t, J = 5.2 Hz, 2H), 3.60 (s, 2H), 3.86
(d, J = 6.4 Hz, 2H), 6.76 (d, J = 8.0 Hz, 1H), 6.96 (d, J = 8.4 Hz, 1H),
7.49 (t, J = 8.2 Hz, 1H), 7.77 (s, 1H); 13C NMR (CDCl3) d 177.45,
159.85, 158.59, 151.83, 133.83, 122.45, 114.86, 109.62, 107.26,
74.87, 61.37, 59.21, 56.15, 49.56, 37.40, 35.63, 31.59, 29.70,
26.62, 26.45, 25.94, 25.75; HRMS: calcd. for C25H35NO4: m/z
413.2566, found: 413.2561.
7.1.1.13. 3-(((4-Chlorobenzyl)(2-hydroxyethyl)amino)methyl)-
7.1.1.8. 5-(Cyclohexylmethoxy)-3-(((cyclohexylmethyl)(2-hydr
5-(cyclohexylmethoxy)-4H-chromen-4-one
40%; yellow oil; Rf: 0.30 (MeOH:CH2Cl2 = 1:30); IR (KBr) 3439,
2922, 1735, 1657, 1268, 1062 cmÀ1 1H NMR (CDCl3) d 1.07–2.06
(m, 11H), 2.65 (t, J = 5.0 Hz, 2H), 3.53 (s, 2H), 3.62 (s, 2H), 3.70 (t,
J = 4.8 Hz, 2H), 3.88 (d, J = 6.0 Hz, 2H), 6.77 (d, J = 8.4 Hz, 1H),
6.94 (d, J = 8.4 Hz, 1H), 7.22 (s, 4H), 7.49 (t, J = 8.4 Hz, 1H), 7.72
(s, 1H); 13C NMR (CDCl3) d 177.60, 159.96, 158.69, 152.01,
133.80, 133.82, 132.81, 130.13, 128.59, 122.37, 115.02, 109.68,
107.44, 74.99, 59.62, 58.07, 55.58, 49.03, 37.52, 29.84, 26.58,
(4m).
Yield
oxyethyl)amino)methyl)-4H-chromen-4-one
29%; yellow oil; Rf: 0.30 (MeOH:CH2Cl2 = 1:30); IR (KBr) 3461,
2927, 1730, 1649, 1273, 1061 cmÀ1 1H NMR (CDCl3) d 1.05–2.06
(4h).
Yield
;
;
(m, 22H), 2.25 (d, J = 6.4 Hz, 2H), 2.63 (t, J = 4.8 Hz, 1H), 3.47 (s,
2H), 3.67 (t, J = 5.2 Hz, 2H), 3.86 (d, J = 6.4 Hz, 2H), 6.76 (d,
J = 8.4 Hz, 1H), 6.95 (d, J = 8.8 Hz, 1H), 7.49 (t, J = 8.6 Hz, 1H), 7.77
(s, 1H); 13C NMR (CDCl3) d 177.72, 159.92, 158.74, 151.89,
133.66, 114.86, 114.83, 109.80, 107.17, 74.92, 59.70, 59.60, 51.71,
45.82, 37.50, 29.88, 28.79, 26.58, 26.24, 26.11, 25.86; HRMS: calcd.
for C26H37NO4: m/z 427.2723, found: 427.2717.
25.88; HRMS: calcd. for
455.1859.
C26H30ClNO4: m/z 455.1863, found:
7.1.1.9. 3-((Benzyl(2-hydroxyethyl)amino)methyl)-5-(cyclohex
7.1.1.14. 5-(Cyclohexylmethoxy)-3-(((2-hydroxyethyl)(pyridin-
4-ylmethyl)amino)methyl)-4H-chromen-4-one (4n). Yield
35%; yellow oil; Rf: 0.29 (MeOH:CH2Cl2 = 1:15); IR (KBr) 3408,
2921, 1744, 1657, 1268, 1064 cmÀ1 1H NMR (CDCl3) d 1.07–2.06
ylmethoxy)-4H-chromen-4-one (4i).
Rf: 0.28 (MeOH:CH2Cl2 = 1:30); IR (KBr) 3412, 2923, 1730, 1657,
1269, 1066 cmÀ1 1H NMR (CDCl3) d 1.07–2.06 (m, 11H), 2.25 (d,
Yield 27%; yellow oil;
;
;
J = 6.4 Hz, 2H), 2.69 (t, J = 4.0 Hz, 1H), 3.56 (s, 2H), 3.68 (s, 2H),
3.69 (t, J = 4.4 Hz, 2H), 3.87 (d, J = 6.4 Hz, 2H), 6.76 (d, J = 8.0 Hz,
1H), 6.93 (d, J = 8.4 Hz, 1H), 7.34–7.19 (m, 5H), 7.48 (t, J = 8.2 Hz,
1H), 7.75 (s, 1H); 13C NMR (CDCl3) d 177.61, 159.96, 158.69,
152.46, 133.78, 129.00, 128.56, 127.36, 115.01, 110.86, 109.73,
107.44, 75.01, 59.47, 58.70, 55.63, 48.94, 37.49, 29.84, 26.58,
(m, 11H), 2.67 (t, J = 4.8 Hz, 2H), 3.56 (s, 2H), 3.67 (s, 2H), 3.75 (t,
J = 5.2 Hz, 2H), 3.93 (d, J = 5.6 Hz, 2H), 6.78 (d, J = 8.4 Hz, 1H),
6.94 (d, J = 8.8 Hz, 1H), 7.25 (d, J = 6.4 Hz, 2H), 7.50 (t, J = 8.4 Hz,
1H), 7.73 (s, 1H), 8.47 (d, J = 6.4 Hz, 2H); 13C NMR (CDCl3) d
177.49, 159.86, 158.57, 151.89, 149.79, 148.71, 132.82, 123.50,
122.01, 114.87, 109.53, 107.40, 74.87, 59.53, 57.60, 55.76, 49.09,
37.40, 29.68, 26.43, 25.75; HRMS: calcd. for C25H30N2O4: m/z
422.2206, found: 422.2200.
25.86; HRMS: calcd. for
421.2246.
C26H31NO4: m/z 421.2253, found:

5762
C. Joo et al. / Bioorg. Med. Chem. 20 (2012) 5757–5762
9. Devos, R.; Guisez, Y.; Plaetinck, G.; Cornelis, S.; Traverier, J.; Van der Heyden, J.;
Acknowledgment
Florey, C. H.; Scheffler, J. E. Eur. J. Biochem. 1994, 225, 635.
10. Min, B.; Oh, S. H.; Lee, H. K.; Takatsu, K.; Chang, I. M.; Min, K. R.; Kim, Y. Planta
Med. 1999, 65, 408.
11. Yun, J.; Lee, C. K.; Chang, I. M.; Takatsu, K.; Hirano, T.; Min, K. R.; Lee, M. K.; Kim,
Y. Life Sci. 2000, 67, 2855.
12. Jung, S.-H.; Cho, S. H.; Dang, T. H.; Lee, J. H.; Ju, J. H.; Kim, M. K.; Lee, S. H.; Ryu, J.
C.; Kim, Y. Eur. J. Med. Chem. 2003, 38, 537.
13. Yang, H. M.; Shin, H. R.; Bang, S. C.; Lee, K. C.; Hoang, L. T. A.; Lee, I. J.; Kim, Y.;
Jung, S.-H. Arch. Pharm. Res. 2007, 30, 950.
This work was supported by Basic Science Research Program
(2011-0014889) and Priority Research Centers Program (2009-
0093815) through the National Research Foundation of Korea
(NRF) funded by the Ministry of Education, Science and
Technology.
14. Yang, H. M.; Shin, H. R.; Cho, S. H.; Song, G. Y.; Lee, I. J.; Kim, M. K.; Lee, S. H.;
Ryu, J. C.; Kim, Y.; Jung, S.-H. Arch. Pharm. Res. 2006, 29, 969.
15. Yang, H. M.; Shin, H. R.; Cho, S. H.; Song, G. Y.; Lee, I. J.; Kim, M. K.; Lee, S. H.;
Ryu, J. C.; Kim, Y.; Jung, S.-H. Bioorg. Med. Chem. 2007, 15, 104.
16. Thanigaimalai, P.; Hoang, T. A-. L.; Lee, K. –C; Sharma, V. K.; Bang, S.-C.; Yun, J.
H.; Roh, E.; Kim, Y.; Jung, S.-H. Eur. J. Med. Chem. 2010, 45, 2531.
17. Thanigaimalai, P.; Lee, K.-C.; Sharma, V. K.; Yun, J. –H.; Kim, Y.; Jung, S.-H.
Bioorg. Med. Chem. 2010, 18, 4625.
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