Synthesis and antimicrobial activities of 7-O-modified genistein derivatives

Article abstract of DOI:10.1016/j.ejmech.2007.09.008

Three series of genistein derivatives with heterocycles were prepared, in which genistein and heterocyclic moieties were separated by 2-carbon, 3-carbon and 4-carbon spacers. Among the 33 compounds we prepared 11 of them (2c and 5a-j) are reported for the

Full text of DOI:10.1016/j.ejmech.2007.09.008

Available online at www.sciencedirect.com
European Journal of Medicinal Chemistry 43 (2008) 1543e1551
http://www.elsevier.com/locate/ejmech
Short communication
Synthesis and antimicrobial activities of 7-O-modified
genistein derivatives
*
Li-Na Zhang, Ping Cao, Shu-Hua Tan, Wen Gu, Lei Shi, Hai-Liang Zhu
School of Life Sciences, Nanjing University, Nanjing 210093, PR China
Received 21 March 2007; received in revised form 30 July 2007; accepted 6 September 2007
Available online 22 September 2007
Abstract
Three series of genistein derivatives with heterocycles were prepared, in which genistein and heterocyclic moieties were separated by 2-car-
bon, 3-carbon and 4-carbon spacers. Among the 33 compounds we prepared 11 of them (2c and 5aej) are reported for the first time, while the
preparation of 2a,b, 3aej and 4aej was reported in our recent paper. All the derivatives were screened for antibacterial (Bacillus subtilis, Staph-
ylococcus aureus, Escherichia coli and Pseudomonas fluorescence) and antifungal (Aspergillus niger, Candida albicans and Trichophyton
rubrum) activities by MTT method. Among the compounds tested, 4a, 4e, 4f, 4h, 5e and 5f exhibited good antibacterial activities while 4a
also showed notable antifungal activity. Especially, 5f exhibited stronger antibacterial activity against B. subtilis and S. aureus comparable to
positive controls.
Ó 2007 Elsevier Masson SAS. All rights reserved.
Keywords: Genistein; Structure modifications; Heterocyclic moieties; Antibacterial activity; Antifungal activity; Structureeactivity relationship
1. Introduction
N-containing heterocyclic moieties have antimicrobial features
[9e11]. Herein, we describe the syntheses of genistein deriv-
atives in which genistein and heterocyclic moieties were
linked by spacers, and our investigation of the effects of the
size of the spacers and substitution patterns of the heterocyclic
moieties.
Our interest in this area is to design and synthesize diverse
biologically active genistein derivatives. In continuation of our
earlier studies [12e14], in this paper we would like to illus-
trate the synthesis and antimicrobial activities of three series
of analogues of genistein. To our knowledge, this is the first
report on the screening of 7-O-modified genistein derivatives
for their antimicrobial activities.
Isoflavonoids are a broad class of polyphenolic secondary
metabolites that are abundant in plants and in various common
foods such as apples, onions, tea, and red wine. Apart from
their important biological roles in nitrogen fixation and chemical
defense, isoflavonoids possess a broad range of pharmacolog-
ical properties, including antioxidant, anticancer and anti-
inflammatory properties [1], and hence received considerable
therapeutic importance.
Genistein (1, shown in Scheme 1), a major metabolite of
soy, is reported to have many biological activities including
antiestrogenic [2], anti-inflammatory [3], antiproliferative
[4], antioxidant [5], antiviral [6], antiallergic [7], antibacterial
effects [8], and so on. The versatile biological activities of
genistein prompted us to prepare a new series of its derivatives
and evaluate their biological significance. Moreover, literature
survey revealed that various types of compounds possessing
2. Chemistry
The synthesis of compounds 3aej and 5aej was acc-
omplished according to the general pathway illustrated in
Scheme 1. Compounds 2aec were the key intermediates for
the synthesis of the compounds investigated. They were
usually prepared from alkylation of 7-OH group by using
* Corresponding author. Tel./fax: þ86 25 8359 2672.
E-mail address: zhuhl@nju.edu.cn (H.-L. Zhu).
0223-5234/$ - see front matter Ó 2007 Elsevier Masson SAS. All rights reserved.
doi:10.1016/j.ejmech.2007.09.008

1544
L.-N. Zhang et al. / European Journal of Medicinal Chemistry 43 (2008) 1543e1551
HO
O
O
3. Biological evaluation and discussion
Br
O
O
n
i
40KHz
OH
All genistein derivatives were screened for their antimicro-
bial activities by MTT method against Bacillus subtilis, Staph-
ylococcus aureus (Gram-positive bacteria), Escherichia coli,
Pseudomonas fluorescence (Gram-negative bacteria), and Tri-
chophyton rubrum, Candida albicans (fungi), which may be
the causal agents of some serious infections in humans. The
minimal inhibitory concentration (MIC) values for the bacteria
and fungi are listed in Table 1. Also included are the activities
of reference compounds kanamycin, penicillin (for bacteria)
and ketoconazole (for fungi).
A few compounds in series 1, which contain 2-carbon
spacer, exhibited moderate activities against S. aureus, B. sub-
tilis and P. fluorescence. In this series, compound 3d showed
pronounced activity against S. aureus and P. fluorescence. In
addition, compound 3a also showed moderate activity against
P. fluorescence.
Several compounds in series 2, which contain 3-carbon
spacer, displayed good activities against the test microorgan-
isms. In this series, compounds 4e, 4f and 4h showed good ac-
tivities against S. aureus, B. subtilis and P. fluorescence.
Among them 4h showed strong activity against S. aureus
with its MIC value (3.4 mg/mL) near to those of positive con-
trols. Notably, compound 4a exhibiting a broad antimicrobial
spectrum against both bacteria and fungi, was the only com-
pound with considerable antifungal activity in this work.
Similarly, several compounds in series 3, which contain
4-carbon spacer, showed good activities against S. aureus,
B. subtilis and P. fluorescence. Among them, compounds 5e
and 5f containing dipropylamine moiety and dibutylamine
moiety, respectively, displayed strong activities against these
three bacteria. Compound 5f exhibited remarkable activities
against S. aureus and B. subtilis with the MICs (1.7 mg/mL
and 3.7 mg/mL, respectively) comparable to that of penicillin.
As shown in Table 1, none of the compounds showed activity
against E. coli with the concentration lower than 50 mg/mL.
From the results it could be deduced that among the com-
pounds those containing alkyl amino side chains showed better
activities against the test bacteria than those containing aro-
matic ring amino side chains. Especially, the derivatives
with diproylamine moiety and dibutylamine moiety were
more active than most of the other analogues. A possible ex-
planation for this result is that the lipophilicity of the genistein
derivatives affected by their side chains played an important
role in their antimicrobial activities.
OH O
OH
OH
1
2a–2c
2a, n = 2
2b, n = 3
2c, n = 4
O
R
O
n
ii
2a–2b
O
OH
OH
(3a–3j), n = 2
(4a–4j), n = 3
(5a–5j), n = 4
N
N(CH CH CH CH )
3 2
(3f–5f); R =
2
2
2
(3a–5a); R =
(3b–5b); R =
(3c–5c); R =
(3d–5d); R =
(3e–5e); R =
N
N CH
3
(3g–5g); R =
N
N
O
NH
O
(3h–5h); R =
(3i–5i); R =
(3j–5j); R =
N
N
H N
N
N
N
N(CH CH CH )
3 2
2
2
Scheme 1. Synthesis of 7-O-heterocycle derivatives of genistein. Reagents and
conditions: (i) BrCH2CH2Br, BrCH2CH2CH2Br or BrCH2CH2CH2CH2Br,
K2CO3, DMF; (ii) R, K2CO3, dioxane, DMF, heating.
1,2-, 1,3- or 1,4-dihaloalkanes in the presence of bases such
as NaOH or K2CO3 in anhydrous acetone [15,16]. However,
to investigate the application of ultrasound in the selective
structure modification of natural polyphenols, ultrasound
was applied hereby for the semisynthesis of genistein
derivatives, and the method [17] we used could, under the
same or similar reaction conditions, remarkably reduce the
reaction time with discernible improvement in the regioselec-
tivity. Thus, derivatives 2aec were prepared through ‘step i’
under ultrasound irradiation by treating 1 with excessive
amounts of 1,2-dibromoethane, 1,3-dibromopropane or 1,4-
dibromobutane. To increase the antimicrobial properties of
genistein, genistein derivatives in which the genistein ring sys-
tem is linked to the alkylamines by different spacers at C-7
position were investigated, with a view to modify their lipophi-
licity. The methods for alkylation of 2aec were well-
documented [18]. The literature survey indicated that the method
reported by Liu et al. [19] is appropriate for N-alkylation of
imidazole or benzimidazole, since the formation of quaternary
imidazolium or benzimidazolium salts, as unwanted side prod-
uct, was usually limited. In this method, 2aec were directly
treated with imidazole or benzimidazole in dioxane to afford
the expected products 3i,j and 4i,j, respectively. Compounds
3aeh and 4aeh were synthesized by a convenient synthetic
route. Reaction of 2aec with different cyclic and noncyclic al-
kylamines yielded 3aeh and 4aeh, respectively.
In conclusion, three series of analogues of genistein were
synthesized in approach of new antimicrobial compounds.
All compounds were examined for their antimicrobial activi-
ties against four bacteria and two fungi, and some struc-
tureeactivity relationships were explored. Compounds in
series 3, which contain 4-carbon spacer between genistein
and the aliphatic amines, displayed a good deal of activities.
These results open the way for investigation of new potential
pharmacophores in the study of antimicrobial agents. The con-
venient syntheses of these compounds make them potential
candidates for further development.
All of the synthetic compounds gave satisfactory analytical
and spectroscopic data, which were in full accordance with
their depicted structures.

L.-N. Zhang et al. / European Journal of Medicinal Chemistry 43 (2008) 1543e1551
1545
Table 1
Antimicrobial activity of the synthesized compounds
Compound
Minimum inhibitory concentrations (mg/mL)
Gram-positive bacteria
Gram-negative bacteria
Fungi
Bacillus
subtilis
Staphylococcus
aureus
Pseudomonas
fluorescence
Escherichia
coli
Trichophyton
rubrum
Candida
albicans
Aspergillus
niger
1
>50
>50
>50
>50
>50
>50
>50
47.5
>50
30.0
>50
>50
>50
>50
48.5
>50
>50
>50
32.0
>50
43.0
12.5
>50
>50
38.5
>50
35.5
15.5
19.5
3.7
>50
>50
>50
>50
49.6
>50
>50
17.5
41.2
32.8
35.5
>50
>50
>50
18.5
>50
>50
40.0
15.3
17.1
>50
3.4
>50
>50
>50
>50
28.5
>50
>50
23.5
47.5
37.0
>50
>50
>50
>50
20.5
>50
>50
>50
45.0
18.5
>50
10.5
>50
>50
23.1
>50
>50
37.5
19.5
13.2
37.4
12.0
>50
>50
>50
>50
>50
>50
>50
>50
>50
>50
>50
>50
>50
>50
>50
>50
>50
>50
>50
>50
>50
>50
>50
>50
>50
>50
>50
>50
>50
>50
>50
>50
>50
>50
>50
>50
>50
>50
>50
>50
>50
>50
>50
>50
>50
>50
>50
>50
>50
>50
21.5
>50
>50
>50
>50
>50
>50
>50
>50
>50
48.5
>50
>50
>50
>50
>50
>50
>50
>50
>50
>50
>50
>50
>50
>50
>50
>50
>50
>50
>50
>50
>50
>50
>50
20.5
>50
>50
>50
>50
>50
>50
>50
>50
>50
>50
>50
>50
>50
>50
>50
>50
>50
>50
>50
>50
>50
>50
>50
39.8
>50
>50
>50
>50
41.6
>50
>50
>50
>50
23.5
>50
>50
>50
>50
>50
>50
45.5
>50
>50
>50
>50
>50
>50
>50
>50
>50
>50
>50
>50
2a
2b
2c
3a
3b
3c
3d
3e
3f
3g
3h
3i
3j
4a
4b
4c
4d
4e
4f
4g
4h
4i
>50
>50
23.7
>50
37.5
20.1
10.5
1.7
4j
5a
5b
5c
5d
5e
5f
5g
5h
5i
30.3
>50
>50
>50
27.2
35.3
>50
21.3
5j
Ketoconazole
Kanamycin
Penicillin
3.9
3.9
7.8
1.0
0.78
1.0
2.0
3.9
3.9
4. Experimental protocols
500 W. The reaction flask was positioned in the maximum-en-
ergy area in the cleaner with water circulated around to control
the temperature of the water bath.
4.1. General
Reactions and the resulted products were monitored by
thin-layer chromatography (TLC) on Merck pre-coated silica
gel F254 plates with separated compounds visualized at
254 nm under a UV lamp. Melting points (uncorrected) were
determined on an XT4 MP apparatus (Taike Corp, Beijing,
China). ESI mass spectra were obtained on a Mariner System
4.2. Chemistry
The reagents (chemicals), all being of A.R. grade, were
purchased from Shanghai Chemical Reagent Company
(Shanghai, China). Genistein (1, >96%) provided by Shanxi
Huike Botanical Development Co. Ltd was further refined
prior to use by its recrystallization from ethanol as pale yellow
needles, mp: 298e299 ꢁC. 1H NMR (DMSO-d6): 6.21 (d,
J ¼ 1.9 Hz, 1H), 6.37 (d, J ¼ 1.9 Hz, 1H), 6.80 (d,
J ¼ 8.5 Hz, 2H), 7.35 (d, J ¼ 8.5 Hz, 2H), 8.32 (s, 1H), 9.64
(s, 1H), 10.94 (s, 1H), 12.96 (s, 1H). ESI-MS C15H10O5
[M ꢂ H]ꢂ 269. Anal. Calcd for C15H10O5: C, 66.67; H, 3.73.
Found: C, 66.68; H, 3.87.
1
5304 mass spectrometer, and H NMR spectra were recorded
in DMSO-d6 on a Bruker DPX500 or DPX300 spectrometer
with solvent signals allotted as internal standard. Elemental
analyses were performed on a CHNeO-Rapid instrument
and were within ꢀ0.4% of the theoretical values. Sonication
was performed in a Kunshan KQ 500E ultrasonic cleaner
(Jiangsu, China) with irradiation delivered at 40 kHz and

1546
L.-N. Zhang et al. / European Journal of Medicinal Chemistry 43 (2008) 1543e1551
The purity of each active compound mentioned in the study
was checked to be >99% through elemental analyses plus
1
HRMS and H NMR spectra.
mixture was filtered, washed with water, dried over Na2SO4
and concentrated. The residue was purified with a silica gel
column and was eluted with CH2Cl2/CH3OH 9:1 to afford
1
3a (0.28 g, 75%), mp: 216e218 ꢁC. H NMR (DMSO-d6):
4.2.1. 7-(2-Bromoethoxy)-5-hydroxy-3-
(4-hydroxyphenyl)-4H-chromen-4-one (2a)
1.91 (br s, 4H), 3.10 (br s, 2H), 3.59 (s, 4H), 4.48 (t, J ¼
5.6 Hz, 2H), 6.49 (d, J ¼ 2.0 Hz, 1H), 6.75 (d, J ¼ 2.0 Hz,
1H), 6.83 (d, J ¼ 8.5 Hz, 1.0 Hz, 2H), 7.39 (d, J ¼ 8.5 Hz,
2H), 8.44 (d, J ¼ 1.0 Hz, 1H), 9.66 (s, 1H), 12.97 (s, 1H).
ESI-MS C21H21NO5 [M þ H]þ 368. Anal. Calcd for
C21H21NO5: C, 68.65; H, 5.76; N, 3.81. Found: C, 68.73; H,
5.62; N, 3.90.
Genistein (0.27 g, 1 mmol), dibromoethane (4.7 g, 25 mmol)
and potassium carbonate (0.07 g, 0.5 mmol) in 60 mL of dry
DMF were sonicated. After the completion of reaction, the
resultant mixture was cooled to room temperature and filtered.
The filtrate was distilled to form yellow solid. Recrystallization
of the solid from 15 mL acetone gave compound 2a (0.33 g,
1
88%) as yellow needles, mp: 175e178 ꢁC. H NMR (DMSO-
4.2.5. 5-Hydroxy-3-(4-hydroxyphenyl)-7-
d6): 4.43 (t, J ¼ 5.5 Hz, 2H), 6.41 (d, J ¼ 2.0 Hz, 1H), 6.67
(d, J ¼ 2.0 Hz, 1H), 6.82 (dd, J ¼ 8.5 Hz, 1.0 Hz, 2H), 7.38
(d, J ¼ 8.5 Hz, 2H), 8.39 (d, J ¼ 1.0 Hz, 1H), 9.64 (s, 1H),
12.95 (s, 1H). ESI-MS C17H13BrO5 [M ꢂ H]ꢂ 375. Anal. Calcd
for C17H13BrO5: C, 54.13; H, 3.47. Found: C, 54.06; H, 3.51.
(2-(piperidin-1-yl)ethoxy)-4H-chromen-4-one (3b)
To a solution of 2a (0.37 g, 1 mmol) in 5 mL of anhydrous
DMF was added piperidine (0.43 g, 5 mmol), followed by
heating at 80 ꢁC for 1 h until the starting material disappeared.
To the reaction mixture was added ice water, dropwise. The
mixture was filtered, washed with water, dried over Na2SO4
and concentrated. The residue was purified with a silica gel
column and was eluted with CH2Cl2/CH3OH 9:1 to afford
3b (0.32 g, 85%), mp: 218e220 ꢁC. The purified product
was dissolved in HCl/water (1:20) and single crystals
4.2.2. 7-(3-Bromopropoxy)-5-hydroxy-3-
(4-hydroxyphenyl)-4H-chromen-4-one (2b)
Genistein (0.27 g, 1 mmol), 1,3-dibromopropane (5.1 g,
25 mmol) and potassium carbonate (0.07 g, 0.5 mmol) in
60 mL of dry DMF were sonicated. After the completion of re-
action, the obtained mixture was cooled to room temperature
and filtered. The filtrate is distilled to give yellow solid. Re-
crystallization of the solid from 15 mL acetone gave com-
pound 2b (0.34 g, 87%) as yellow needles, mp: 124e126 ꢁC.
1H NMR (DMSO-d6): 2.25 (m, 2H), 3.65 (t, J ¼ 5.5 Hz,
2H), 4.18 (t, J ¼ 5.5 Hz, 2H), 6.42 (s, 1H), 6.67 (s, 1H),
6.82 (d, J ¼ 8.5 Hz, 2H), 7.38 (d, J ¼ 8.5 Hz, 2H), 8.40 (s,
1H), 9.63 (s, 1H), 12.95 (s, 1H). ESI-MS C18H15BrO5
[M ꢂ H]ꢂ 389. Anal. Calcd for C18H15BrO5: C, 55.26; H,
3.86. Found: C, 55.14; H, 3.80.
1
(Fig. 1) were obtained after 6 d. H NMR (DMSO-d6): 1.37
(m, 2H), 1.47e1.50 (m, 4H), 2.08 (br s, 4H), 2.67 (t, J ¼
5.6 Hz, 2H), 4.19 (t, J ¼ 5.6 Hz, 2H), 6.41 (d, J ¼ 2.0 Hz,
1H), 6.67 (d, J ¼ 2.0 Hz, 1H), 6.82 (d, J ¼ 8.5 Hz, 1.0 Hz,
2H), 7.38 (d, J ¼ 8.5 Hz, 2H), 8.39 (d, J ¼ 1.0 Hz, 1H), 9.64
(s, 1H), 12.95 (s, 1H). ESI-MS C22H23NO5 [M þ H]þ 382.
Anal. Calcd for C22H23NO5: C, 69.28; H, 6.08; N, 3.67.
Found: C, 69.31; H, 5.92; N, 3.71.
4.2.6. 5-Hydroxy-3-(4-hydroxyphenyl)-7-
(2-morpholinoethoxy)-4H-chromen-4-one (3c)
To a solution of 2a (0.37 g, 1 mmol) in 5 mL of anhydrous
DMF was added morpholine (0.44 g, 5 mmol), followed by
heating at 80 ꢁC for 1 h until the starting material disappeared.
To the reaction mixture was added ice water, dropwise. The
mixture was filtered, washed with water, dried over Na2SO4
and concentrated. The residue was purified with a silica gel
column and was eluted with CH2Cl2/CH3OH 9:1 to give 3c
4.2.3. 7-(4-Bromobutoxy)-5-hydroxy-3-
(4-hydroxyphenyl)-4H-chromen-4-one (2c)
Genistein (0.27 g, 1 mmol), 1,4-dibromobutane (5.4 g,
25 mmol) and potassium carbonate (0.07 g, 0.5 mmol) in
60 mL of dry DMF were sonicated. After the completion of re-
action, the resultant mixture was cooled to room temperature
and filtered. The filtrate was distilled to form yellow solid. Re-
crystallization of the solid from 15 mL acetone gave com-
pound 2c (0.33 g, 83%) as yellow needles, mp: 130e131 ꢁC.
1H NMR (DMSO-d6): 1.83 (m, 2H), 1.94 (m, 2H), 3.60 (t, J ¼
6.2 Hz, 2H), 4.12 (t, J ¼ 6.4 Hz, 2H), 6.40 (d, J ¼ 2.0 Hz, 1H),
6.65 (d, J ¼ 2.0 Hz, 1H), 6.80 (d, J ¼ 8.5 Hz, 2H), 7.38 (d,
J ¼ 8.5 Hz, 2H), 8.40 (s, 1H), 9.65 (s, 1H), 12.95 (s, 1H).
ESI-MS C19H17BrO5 [M þ H]þ 405. Anal. Calcd for
C19H17BrO5: C, 56.31; H, 4.23. Found: C, 56.28; H, 4.27.
1
(0.31 g, 82%), mp: 174e176 ꢁC. H NMR (DMSO-d6): 2.50
(4H, overlapped with H2O protons’ peak), 2.71 (t, J ¼ 5.6 Hz,
2H), 3.58 (t, J ¼ 5.6 Hz, 4H), 4.22 (t, J ¼ 5.6 Hz, 2H), 6.41 (d,
J ¼ 2.0 Hz, 1H), 6.67 (d, J ¼ 2.0 Hz, 1H), 6.82 (d, J ¼ 8.5 Hz,
1.0 Hz, 2H), 7.38 (d, J ¼ 8.5 Hz, 2H), 8.39 (d, J ¼ 1.0 Hz, 1H),
4.2.4. 5-Hydroxy-3-(4-hydroxyphenyl)-7-
(2-(pyrrolidin-1-yl)ethoxy)-4H-chromen-4-one (3a)
To a solution of 2a (0.37 g, 1 mmol) in 5 mL of anhydrous
DMF was added pyrrolidine (0.36 g, 5 mmol), followed by
heating at 80 ꢁC for 1 h until the starting material disappeared.
To the reaction mixture was added ice water, dropwise. The
Fig. 1. Molecular structure of compound 3b with 30% probability of the
ellipsoids.

L.-N. Zhang et al. / European Journal of Medicinal Chemistry 43 (2008) 1543e1551
1547
9.64 (s, 1H), 12.95 (s, 1H). ESI-MS C21H21NO6 [M þ H]þ
4.2.10. 5-Hydroxy-3-(4-hydroxyphenyl)-7-
384. Anal. Calcd for C21H21NO6: C, 65.79; H, 5.52; N,
3.65. Found: C, 65.83; H, 5.42; N, 3.69.
(2-(4-methylpiperazin-1-yl)ethoxy)-4H-chromen-4-one (3g)
To a solution of 2a (0.37 g, 1 mmol) in 5 mL of anhydrous
DMF was added 1-methyl-piperazine (0.50 g, 5 mmol), fol-
lowed by heating at 80 ꢁC for 1 h until the starting material
disappeared. To the reaction mixture was added ice water,
dropwise. The mixture was filtered, washed with water, dried
over Na2SO4 and concentrated. The residue was purified with
a silica gel column and was eluted with CH2Cl2/CH3OH 9:1 to
4.2.7. 5-Hydroxy-3-(4-hydroxyphenyl)-7-
(2-(piperazin-1-yl)ethoxy)-4H-chromen-4-one (3d)
To a solution of 2a (0.37 g, 1 mmol) in 5 mL of anhydrous
DMF was added piperazine (0.43 g, 5 mmol), followed by
heating at 80 ꢁC for 1 h until the starting material disappeared.
To the reaction mixture was added ice water, dropwise. The
mixture was filtered, washed with water, dried over Na2SO4
and concentrated. The residue was purified with a silica gel
column and was eluted with CH2Cl2/CH3OH 9:1 to afford
1
afford 3g (0.36 g, 91%), mp: 114e115 ꢁC. H NMR (DMSO-
d6): 2.14 (s, 3H), 2.32 (br s, 8H), 2.69 (t, J ¼ 5.5 Hz, 2H), 6.40
(s, 1H), 6.67 (s, 1H), 6.82 (d, J ¼ 8.4 Hz, 2H), 7.39 (d,
J ¼ 8.4 Hz, 2H), 8.40 (s, 1H), 9.61 (s, 1H), 12.94 (s, 1H).
ESI-MS C22H24N2O5 [M þ H]þ 367. Anal. Calcd for
C22H24N2O5: C, 66.65; H, 6.10; N, 7.07. Found: C, 65.89;
H, 6.02; N, 7.76.
1
3d (0.30 g, 78%), mp: 225e226 ꢁC. H NMR (DMSO-d6):
2.10 (s, 1H), 2.40 (br s, 4H), 2.67e2.72 (m, 6H), 4.19 (t,
J ¼ 9.0 Hz, 2H), 6.41 (s, 1H), 6.68 (s, 1H), 6.82 (d,
J ¼ 8.5 Hz, 2H), 7.38 (d, J ¼ 8.5 Hz, 2H), 8.40 (s, 1H), 9.61
(s, 1H), 12.94 (s, 1H). ESI-MS C21H22N2O5 [M þ H]þ 383.
Anal. Calcd for C21H22N2O5: C, 65.96; H, 5.80; N, 7.33.
Found: C, 65.87; H, 5.86; N, 7.28.
4.2.11. 7-(2-(Furan-2-yl-methylamino)ethoxy)-5-
hydroxy-3-(4-hydroxyphenyl)-4H-chromen-4-one (3h)
To a solution of 2a (0.37 g, 1 mmol) in 5 mL of anhydrous
DMF was added 2-furan-2-yl-methylamine (0.49 g, 5 mmol),
followed by heating at 80 ꢁC for 1 h until the starting material
disappeared. To the reaction mixture was added ice water,
dropwise. The mixture was filtered, washed with water, dried
over Na2SO4 and concentrated. The residue was purified with
a silica gel column and was eluted with CH2Cl2/CH3OH 9:1 to
4.2.8. 7-(2-(Dipropylamino)ethoxy)-5-hydroxy-3-
(4-hydroxyphenyl)-4H-chromen-4-one (3e)
To a solution of 2a (0.37 g, 1 mmol) in 5 mL of anhydrous
DMF was added dipropylamine (0.51 g, 5 mmol), followed by
heating at 80 ꢁC for 1 h until the starting material disappeared.
To the reaction mixture was added ice water, dropwise. The
mixture was filtered, washed with water, dried over Na2SO4
and concentrated. The residue was purified with a silica gel
column and was eluted with CH2Cl2/CH3OH 9:1 to afford
1
afford 3h (0.31 g, 79%), mp: 211e212 ꢁC. H NMR (DMSO-
d6): 3.23 (br s, 2H), 4.18 (s, 2H), 4.32 (s, 2H), 6.45 (s, 1H),
6.51 (m, 1H), 6.56 (m, 1H), 6.70 (s, 1H), 6.83 (d,
J ¼ 8.0 Hz, 2H), 7.39 (d, J ¼ 8.0 Hz, 2H), 7.73 (m, 1H), 8.44
(s, 1H), 9.65 (s, 1H), 12.98 (s, 1H). ESI-MS C22H19NO6
[M þ H]þ 394. Anal. Calcd for C22H19NO6: C, 67.17; H,
4.87; N, 3.56. Found: C, 67.10; H, 4.76; N, 3.61.
1
3e (0.33 g, 82%), mp: 223e224 ꢁC. H NMR (DMSO-d6):
0.84 (t, J ¼ 7.2 Hz, 6H), 1.39e1.42 (m, 4H), 2.42 (t,
J ¼ 7.1 Hz, 4H), 2.78 (t, J ¼ 5.6 Hz, 2H), 4.13 (t, J ¼ 5.6 Hz,
2H), 6.37 (d, J ¼ 2.0 Hz, 1H), 6.64 (d, J ¼ 2.0 Hz, 1H), 6.83
(d, J ¼ 8.5 Hz, 1.0 Hz, 2H), 7.39 (d, J ¼ 8.5 Hz, 2H), 8.40
(d, J ¼ 1.0 Hz, 1H), 9.60 (s, 1H), 12.92 (s, 1H). ESI-MS
C21H21NO5 [M þ H]þ 398. Anal. Calcd for C21H21NO5: C,
69.50; H, 6.85; N, 3.52. Found: C, 69.62; H, 6.78; N, 3.59.
4.2.12. 7-(2-(1H-Imidazol-1-yl)ethoxy)-5-
hydroxy-3-(4-hydroxyphenyl)-4H-chromen-4-one (3i)
To a solution of 2a (0.37 g, 1 mmol) in 20 mL of dioxane
was added imidazole (0.41 g, 6 mmol), followed by heating
at reflux for 12 h until the starting material disappeared. To
the reaction mixture was added ice water, dropwise. The mix-
ture was filtered, washed with water, dried over Na2SO4 and
concentrated. The residue was purified with a silica gel col-
umn and was eluted with CH2Cl2/CH3OH 9:1 to afford 3i
4.2.9. 7-(2-(Dibutylamino)ethoxy)-5-hydroxy-3-
(4-hydroxyphenyl)-4H-chromen-4-one (3f)
To a solution of 2a (0.37 g, 1 mmol) in 5 mL of anhydrous
DMF was added dibutylamine (0.65 g, 5 mmol), followed by
heating at 80 ꢁC for 1 h until the starting material disappeared.
To the reaction mixture was added ice water, dropwise. The
mixture was filtered, washed with water, dried over Na2SO4
and concentrated. The residue was purified with a silica gel
column and was eluted with CH2Cl2/CH3OH 9:1 to afford 3f
1
(0.41 g, 68%), mp: 210e212 ꢁC. H NMR (DMSO-d6): 4.39
(s, 4H), 6.42 (d, J ¼ 1.98 Hz, 1H), 6.67 (d, J ¼ 1.98 Hz, 1H),
6.82 (d, J ¼ 8.5 Hz, 2H), 6.90 (s, 1H), 7.25 (s, 1H), 7.38 (d,
J ¼ 8.5 Hz, 2H), 7.69 (s, 1H), 8.40 (s, 1H), 9.59 (s, 1H),
12.95 (s, 1H). ESI-MS C20H16N2O5 [M þ H]þ 365. Anal.
Calcd for C20H16N2O5: C, 65.93; H, 4.43; N, 7.69. Found:
C, 65.97; H, 4.41; N, 7.68.
1
(0.34 g, 81%), mp: 120e121 ꢁC. H NMR (DMSO-d6): 0.87
(t, J ¼ 7.1 Hz, 6H), 1.28 (m, 4H), 1.38 (m, 4H), 2.50 (4H,
overlapped with H2O protons’ peak), 2.81 (br s, 2H), 4.15
(br s, 2H), 6.37 (d, J ¼ 2.0 Hz, 1H), 6.64 (d, J ¼ 2.0 Hz, 1H),
6.83 (d, J ¼ 8.5 Hz, 1.0 Hz, 2H), 7.39 (d, J ¼ 8.5 Hz, 2H), 8.40
(d, J ¼ 1.0 Hz, 1H), 9.60 (s, 1H), 12.95 (s, 1H). ESI-MS
C25H31NO5 [M þ H]þ 426. Anal. Calcd for C25H31NO5: C,
70.57; H, 7.34; N, 3.29. Found: C, 70.49; H, 7.26; N, 3.32.
4.2.13. 7-(2-(1H-benzimidazolium-1-yl)ethoxy)-5-
hydroxy-3-(4-hydroxyphenyl)-4H-chromen-4-one (3j)
To a solution of 2a (0.37 g, 1 mmol) in 20 mL of dioxane
was added benzimidazole (0.71 g, 6 mmol), followed by heat-
ing at reflux for 24 h until the starting material disappeared. To
the reaction mixture was added ice water, dropwise. The

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L.-N. Zhang et al. / European Journal of Medicinal Chemistry 43 (2008) 1543e1551
mixture was filtered, washed with water, dried over Na2SO4
and concentrated. The residue was purified with a silica gel
column and was eluted with CH2Cl2/CH3OH 9:1 to afford 3j
(m, 2H), 2.36e2.37 (m, 4H), 2.41 (t, J ¼ 7.0 Hz, 2H), 3.56e
3.57 (m, 4H), 4.14 (t, J ¼ 6.0 Hz, 2H), 6.39 (s, 1H), 6.65 (s,
1H), 6.82 (d, J ¼ 8.5 Hz, 2H), 7.40 (d, J ¼ 8.5 Hz, 2H), 8.40
(s, 1H), 9.59 (s, 1H), 12.94 (s, 1H). ESI-MS C22H23NO6
[M þ H]þ 398. Anal. Calcd for C22H23NO6: C, 66.49; H,
5.83; N, 3.52. Found: C, 66.51; H, 5.76; N, 3.47.
1
(0.27 g, 86%), mp: 230e232 ꢁC. H NMR (DMSO-d6): 4.47
(br s, 2H), 4.69 (br s, 2H), 6.34 (s, 1H), 6.59 (s, 1H), 6.82
(d, J ¼ 7.8 Hz, 2H), 7.21 (t, J ¼ 7.1 Hz, 1H), 7.29 (t,
J ¼ 7.1 Hz, 1H), 7.36 (d, J ¼ 7.8 Hz, 2H), 7.64 (d, J ¼ 7.9
Hz, 1H), 7.70 (d, J ¼ 7.9 Hz, 1H), 8.28 (s, 1H), 8.37 (s, 1H),
9.62 (s, 1H), 12.96 (s, 1H). ESI-MS C24H18N2O5 [M þ H]þ
415. Anal. Calcd for C24H18N2O5: C, 69.56; H, 4.38; N,
6.76. Found: C, 69.57; H, 4.30; N, 6.77.
4.2.17. 5-Hydroxy-3-(4-hydroxyphenyl)-7-
(3-(piperazin-1-yl)propoxy)-4H-chromen-4-one (4d)
To a solution of 2b (0.37 g, 1 mmol) in 5 mL of anhydrous
DMF was added piperazine (0.43 g, 5 mmol), followed by
heating at 80 ꢁC for 1 h until the starting material disappeared.
To the reaction mixture was added ice water, dropwise. The
mixture was filtered, washed with water, dried over Na2SO4
and concentrated. The residue was purified with a silica gel
column and was eluted with CH2Cl2/CH3OH 9:1 to afford
4.2.14. 5-Hydroxy-3-(4-hydroxyphenyl)-7-
(3-(pyrrolidin-1-yl)propoxy)-4H-chromen-4-one (4a)
To a solution of 2b (0.37 g, 1 mmol) in 5 mL of anhydrous
DMF was added pyrrolidine (0.36 g, 5 mmol), followed by
heating at 80 ꢁC for 1 h until the starting material disappeared.
To the reaction mixture was added ice water, dropwise. The
mixture was filtered, washed with water, dried over Na2SO4
and concentrated. The residue was purified with a silica gel
column and was eluted with CH2Cl2/CH3OH 9:1 to afford
1
4d (0.30 g, 76%), mp: 210e211 ꢁC. H NMR (DMSO-d6):
1.87 (m, 2H), 2.10 (s, 1H), 2.30 (br s, 4H), 2.37 (t,
J ¼ 7.0 Hz, 2H), 2.68 (br s, 4H), 4.12 (t, J ¼ 6.2 Hz, 2H),
6.40 (s, 1H), 6.64 (s, 1H), 6.82 (d, J ¼ 8.5 Hz, 2H), 7.40 (d,
J ¼ 8.5 Hz, 2H), 8.40 (s, 1H), 9.59 (s, 1H), 12.94 (s, 1H).
ESI-MS C22H24N2O5 [M þ H]þ 397. Anal. Calcd for
C22H24N2O5: C, 66.65; H, 6.10; N, 7.07. Found: C, 66.71;
H, 6.02; N, 7.13.
1
4a (0.30 g, 80%), mp: 180e181 ꢁC. H NMR (DMSO-d6):
1.68 (br s, 4H), 1.89 (m, 2H), 2.43 (br s, 4H), 2.52 (t,
J ¼ 7.2 Hz, 2H), 4.13 (t, J ¼ 6.25 Hz, 2H), 6.38 (s, 1H), 6.64
(s, 1H), 6.82 (d, J ¼ 8.5 Hz, 2H), 7.38 (d, J ¼ 8.5 Hz, 2H),
8.40 (s, 1H), 9.59 (s, 1H), 12.92 (s, 1H). ESI-MS
C22H23NO5 [M þ H]þ 382. Anal. Calcd for C22H23NO5: C,
69.28; H, 6.08; N, 3.67. Found: C, 69.32; H, 6.01; N, 3.73.
4.2.18. 7-(3-(Dipropylamino)propoxy)-5-
hydroxy-3-(4-hydroxyphenyl)-4H-chromen-4-one (4e)
To a solution of 2b (0.37 g, 1 mmol) in 5 mL of anhydrous
DMF was added dipropylamine (0.51 g, 5 mmol), followed
by heating at 80 ꢁC for 1 h until the starting material disap-
peared. To the reaction mixture was added ice water, dropwise.
The mixture was filtered, washed with water, dried over
Na2SO4 and concentrated. The residue was purified with a silica
gel column and was eluted with CH2Cl2/CH3OH 9:1 to afford
4.2.15. 5-Hydroxy-3-(4-hydroxyphenyl)-7-
(3-(piperidin-1-yl)propoxy)-4H-chromen-4-one (4b)
To a solution of 2b (0.37 g, 1 mmol) in 5 mL of anhydrous
DMF was added piperidine (0.43 g, 5 mmol), followed by
heating at 80 ꢁC for 1 h until the starting material disappeared.
To the reaction mixture was added ice water, dropwise. The
mixture was filtered, washed with water, dried over Na2SO4
and concentrated. The residue was purified with a silica gel
column and was eluted with CH2Cl2/CH3OH 9:1 to afford
1
4e (0.35 g, 86%), mp: 218e220 ꢁC. H NMR (DMSO-d6):
0.92 (t, J ¼ 7.3 Hz, 6H), 1.66 (m, 4H), 2.13 (m, 2H), 3.06 (br
s, 4H), 3.23 (br s, 2H), 4.20 (t, J ¼ 5.7 Hz, 2H), 6.43 (s, 1H),
6.67 (s, 1H), 6.82 (d, J ¼ 8.5 Hz, 2H), 7.40 (d, J ¼ 8.5 Hz,
2H), 8.43 (s, 1H), 9.60 (s, 1H), 12.97 (s, 1H). ESI-MS
C24H29NO5 [M þ H]þ 412. Anal. Calcd for C24H29NO5: C,
70.05; H, 7.10; N, 3.40. Found: C, 69.93; H, 7.08; N, 3.47.
1
4b (0.34 g, 86%), mp: 192e194 ꢁC. H NMR (DMSO-d6):
1.37 (br s, 2H), 1.48e1.49 (m, 4H), 1.87 (m, 2H), 2.32e
2.34 (m, 4H), 2.37 (t, J ¼ 7.1 Hz, 2H), 4.12 (t, J ¼ 6.0 Hz,
2H), 6.39 (s, 1H), 6.65 (s, 1H), 6.82 (d, J ¼ 8.5 Hz, 2H),
7.40 (d, J ¼ 8.5 Hz, 2H), 8.40 (s, 1H), 9.59 (s, 1H), 12.92 (s,
1H). ESI-MS C23H25NO5 [M þ H]þ 396. Anal. Calcd for
C23H25NO5: C, 69.86; H, 6.37; N, 3.54. Found: C, 68.91; H,
6.32; N, 3.61.
4.2.19. 7-(3-(Dibutylamino)propoxy)-5-
hydroxy-3-(4-hydroxyphenyl)-4H-chromen-4-one (4f)
To a solution of 2b (0.37 g, 1 mmol) in 5 mL of anhydrous
DMF was added dibutylamine (0.65 g, 5 mmol), followed by
heating at 80 ꢁC for 1 h until the starting material disappeared.
To the reaction mixture was added ice water, dropwise. The
mixture was filtered, washed with water, dried over Na2SO4
and concentrated. The residue was purified with a silica gel
column and was eluted with CH2Cl2/CH3OH 9:1 to afford 4f
4.2.16. 5-Hydroxy-3-(4-hydroxyphenyl)-7-
(3-morpholinopropoxy)-4H-chromen-4-one (4c)
To a solution of 2b (0.37 g, 1 mmol) in 5 mL of anhydrous
DMF was added morpholine (0.44 g, 5 mmol), followed by
heating at 80 ꢁC for 1 h until the starting material disappeared.
To the reaction mixture was added ice water, dropwise. The
mixture was filtered, washed with water, dried over Na2SO4
and concentrated. The residue was purified with a silica gel
column and was eluted with CH2Cl2/CH3OH 9:1 to afford
1
(0.37 g, 85%), mp: 176e178 ꢁC. H NMR (DMSO-d6): 0.90
(t, J ¼ 7.1 Hz, 6H), 1.32 (m, 4H), 1.55 (m, 4H), 2.08 (m,
2H), 2.87 (t, J ¼ 7.8 Hz, 2H), 3.11 (br s, 2H), 4.20 (t,
J ¼ 5.6 Hz, 2H), 6.42 (s, 1H), 6.66 (s, 1H), 6.82 (d,
J ¼ 8.5 Hz, 2H), 7.40 (d, J ¼ 8.5 Hz, 2H), 8.43 (s, 1H), 9.60
(s, 1H), 12.96 (s, 1H). ESI-MS C26H33NO5 [M þ H]þ 440.
1
4c (0.32 g, 86%), mp: 218e219 ꢁC. H NMR (DMSO-d6): 1.88

L.-N. Zhang et al. / European Journal of Medicinal Chemistry 43 (2008) 1543e1551
1549
Anal. Calcd for C26H33NO5: C, 71.05; H, 7.57; N, 3.19.
Found: C, 71.12; H, 7.40; N, 3.18.
heating at reflux for 24 h until the starting material 2b disap-
peared. To the reaction mixture was added ice water, dropwise.
The mixture was filtered, washed with water, dried over
Na2SO4 and concentrated. The residue was purified with a sil-
ica gel column and was eluted with CH2Cl2/CH3OH 9:1 to af-
ford 4j (0.28 g, 66%), mp: 268e270 ꢁC. 1H NMR (DMSO-d6):
2.29 (m, 2H), 4.06 (t, J ¼ 5.4 Hz, 2H), 4.44 (t, J ¼ 6.5 Hz, 2H),
6.38 (s, 1H), 6.60 (s, 1H), 6.82 (d, J ¼ 8.5 Hz, 2H), 7.19 (t, J ¼
6.8 Hz, 1H), 7.24 (t, J ¼ 7.1 Hz, 1H), 7.40 (d, J ¼ 8.5 Hz, 2H),
7.62 (d, J ¼ 7.9 Hz, 1H), 7.65 (d, J ¼ 7.9 Hz, 1H), 8.23 (s, 1H),
8.40 (s, 1H), 9.60 (s, 1H), 12.95 (s, 1H). ESI-MS C25H20N2O5
[M þ H]þ 429. Anal. Calcd for C25H20N2O5: C, 70.08; H, 4.71;
N, 6.54. Found: C, 70.15; H, 4.64; N, 6.50.
4.2.20. 5-Hydroxy-3-(4-hydroxyphenyl)-7-
(3-(4-methylpiperazin-1-yl)propoxy)-4H-chromen-4-one (4g)
To a solution of 2b (0.37 g, 1 mmol) in 5 mL of anhydrous
DMF was added 1-methyl-piperazine (0.50 g, 5 mmol), fol-
lowed by heating at 80 ꢁC for 1 h until the starting material
disappeared. To the reaction mixture was added ice water,
dropwise. The mixture was filtered, washed with water, dried
over Na2SO4 and concentrated. The residue was purified with
a silica gel column and was eluted with CH2Cl2/CH3OH 9:1 to
1
afford 4g (0.37 g, 90%), mp: 110e111 ꢁC. H NMR (DMSO-
d6): 1.87 (br s, 2H), 2.15 (s, 3H), 2.40 (br s, 8H), 4.12 (br s,
2H), 6.39 (s, 1H), 6.64 (s, 1H), 6.82 (d, J ¼ 8.4 Hz, 2H),
7.38 (d, J ¼ 8.4 Hz, 2H), 8.40 (s, 1H), 9.61 (s, 1H), 12.94 (s,
1H). ESI-MS C23H26N2O5 [M þ H]þ 411. Anal. Calcd for
C23H26N2O5: C, 67.30; H, 6.38; N, 6.82. Found: C, 67.21;
H, 6.43; N, 6.75.
4.2.24. 5-Hydroxy-3-(4-hydroxyphenyl)-7-
(4-(pyrrolidin-1-yl)butoxy)-4H-chromen-4-one (5a)
To a solution of 2c (0.40 g, 1 mmol) in 5 mL of anhydrous
DMF was added pyrrolidine (0.36 g, 5 mmol), followed by
heating at 80 ꢁC for 1 h until the starting material disappeared.
To the reaction mixture was added ice water, dropwise. The
mixture was filtered, washed with water, dried over Na2SO4
and concentrated. The residue was purified with a silica gel
column and was eluted with CH2Cl2/CH3OH 9:1 to afford
4.2.21. 7-(3-(Furan-2-yl-methylamino)propoxy)-5-
hydroxy-3-(4-hydroxyphenyl)-4H-chromen-4-one (4h)
To a solution of 2b (0.37 g, 1 mmol) in 5 mL of anhydrous
DMF was added 2-furan-2-yl-methylamine (0.49 g, 5 mmol),
followed by heating at 80 ꢁC for 1 h until the starting material
disappeared. To the reaction mixture was added ice water,
dropwise. The mixture was filtered, washed with water, dried
over Na2SO4 and concentrated. The residue was purified with
a silica gel column and was eluted with CH2Cl2/CH3OH 9:1 to
1
5a (0.28 g, 70%), mp: 190 ꢁC. H NMR (DMSO-d6): 1.74e
1.89 (m, 8H), 2.87e2.96 (m, 6H), 4.10 (t, J ¼ 6.3 Hz, 2H),
6.40 (d, J ¼ 2.0 Hz, 1H), 6.65 (d, J ¼ 2.0 Hz, 1H), 6.81 (d,
J ¼ 8.5 Hz, 2H), 7.38 (d, J ¼ 8.5 Hz, 2H), 8.39 (s, 1H), 9.65
(s, 1H), 12.95 (s, 1H). ESI-MS C23H25NO5 [M þ H]þ 396.
Anal. Calcd for C23H25NO5: C, 69.86; H, 6.37; N, 3.54.
Found: C, 69.80; H, 6.31; N, 3.61.
1
afford 4h (0.29 g, 70%), mp: 209e210 ꢁC. H NMR (DMSO-
d6): 2.10 (br s, 2H), 3.05 (br s, 2H), 4.18 (s, 2H), 4.25 (s, 2H),
6.40 (s, 1H), 6.51 (m, 1H), 6.64 (m, 2H), 6.83 (d, J ¼ 8.6 Hz,
2H), 7.39 (d, J ¼ 8.6 Hz, 2H), 7.77 (m, 1H), 8.40 (s, 1H), 9.65
(s, 1H), 12.98 (s, 1H). ESI-MS C23H21NO6 [M þ H]þ 408.
Anal. Calcd for C23H21NO6: C, 67.80; H, 5.20; N, 3.44.
Found: C, 67.72; H, 5.23; N, 3.49.
4.2.25. 5-Hydroxy-3-(4-hydroxyphenyl)-7-(4-(piperidin-
1-yl)butoxy)-4H-chromen-4-one (5b)
To a solution of 2c (0.40 g, 1 mmol) in 5 mL of anhydrous
DMF was added piperidine (0.43 g, 5 mmol), followed by
heating at 80 ꢁC for 1 h until the starting material disappeared.
To the reaction mixture was added ice water, dropwise. The
mixture was filtered, washed with water, dried over Na2SO4
and concentrated .The residue was purified with a silica gel
column and was eluted with CH2Cl2/CH3OH 9:1 to afford
4.2.22. 7-(3-(1H-Imidazol-1-yl)propoxy)-5-
hydroxy-3-(4-hydroxyphenyl)-4H-chromen-4-one (4i)
To a solution of 2b (0.37 g, 1 mmol) in 20 mL of dioxane
was added imidazole (0.41 g, 6 mmol), followed by heating
at reflux for 12 h until the starting material disappeared. To
the reaction mixture was added ice water, dropwise. The mix-
ture was filtered, washed with water, dried over Na2SO4 and
concentrated. The residue was purified with a silica gel col-
umn and was eluted with CH2Cl2/CH3OH 9:1 to afford 4i
1
5b (0.35 g, 86%), mp: 176 ꢁC. H NMR (DMSO-d6): 1.35e
1.55 (m, 8H), 1.69 (m, 2H), 2.22e2.27 (m, 6H), 4.08 (t, J ¼
6.4 Hz, 2H), 6.38 (d, J ¼ 2.0 Hz, 1H), 6.62 (d, J ¼ 2.0 Hz,
1H), 6.80 (d, J ¼ 8.5 Hz, 2H), 7.37 (d, J ¼ 8.5 Hz, 2H), 8.39
(s, 1H), 9.63 (s, 1H), 12.94 (s, 1H). ESI-MS C24H27NO5
[M þ H]þ 410. Anal. Calcd for C24H27NO5: C, 70.40; H,
6.65; N, 3.42. Found: C, 70.35; H, 6.68; N, 3.47.
1
(0.26 g, 70%), mp: 230e231 ꢁC. H NMR (DMSO-d6): 2.19
(m, 2H), 4.03 (t, J ¼ 5.8 Hz, 2H), 4.14 (t, J ¼ 6.8 Hz, 2H),
6.40 (s, 1H), 6.64 (s, 1H), 6.82 (d, J ¼ 8.5 Hz, 2H), 6.91 (s,
1H), 7.21 (s, 1H), 7.40 (d, J ¼ 8.5 Hz, 2H), 7.66 (s, 1H),
8.40 (s, 1H), 9.61 (s, 1H), 12.95 (s, 1H). ESI-MS
C21H18N2O5 [M þ H]þ 379. Anal. Calcd for C21H18N2O5: C,
66.66; H, 4.79; N, 7.40. Found: C, 66.59; H, 4.82; N, 7.46.
4.2.26. 5-Hydroxy-3-(4-hydroxyphenyl)-7-
(4-morpholinobutoxy)-4H-chromen-4-one (5c)
To a solution of 2c (0.40 g, 1 mmol) in 5 mL of anhydrous
DMF was added morpholine (0.44 g, 5 mmol), followed by
heating at 80 ꢁC for 1 h until the starting material disappeared.
To the reaction mixture was added ice water, dropwise. The
mixture was filtered, washed with water, dried over Na2SO4
and concentrated. The residue was purified with a silica gel
column and was eluted with CH2Cl2/CH3OH 9:1 to give 5c
4.2.23. 7-(3-(1H-benzimidazolium-1-yl)propoxy)-5-
hydroxy-3-(4-hydroxyphenyl)-4H-chromen-4-one (4j)
To a solution of 2b (0.37 g, 1 mmol) in 20 mL of dioxane
was added benzimidazole (0.71 g, 6 mmol), followed by

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L.-N. Zhang et al. / European Journal of Medicinal Chemistry 43 (2008) 1543e1551
1
(0.34 g, 83%), mp: 178e179 ꢁC. H NMR (DMSO-d6): 1.58
(m, 2H), 1.75 (m, 2H), 2.30e2.34 (m, 6H), 3.57 (m, 6H),
4.11 (t, J ¼ 6.3 Hz, 2H), 6.39 (d, J ¼ 2.0 Hz, 1H), 6.64 (d,
J ¼ 2.0 Hz, 1H), 6.80 (d, J ¼ 8.5 Hz, 2H), 7.38 (d,
J ¼ 8.5 Hz, 2H), 8.40 (s, 1H), 9.61 (s, 1H), 12.95 (s, 1H).
ESI-MS C23H25NO6 [M þ H]þ 412. Anal. Calcd for
C23H25NO6: C, 67.14; H, 6.12; N, 3.40. Found: C, 67.21; H,
6.03; N, 3.47.
(d, J ¼ 2.0 Hz, 1H), 6.64 (d, J ¼ 2.0 Hz, 1H), 6.80 (d,
J ¼ 8.5 Hz, 2H), 7.36 (d, J ¼ 8.5 Hz, 2H), 8.40 (s, 1H), 9.61
(s, 1H), 12.92 (s, 1H). ESI-MS C27H35NO5 [M þ H]þ 454.
Anal. Calcd for C27H35NO5: C, 71.50; H, 7.18; N, 3.09.
Found: C, 71.42; H, 7.24; N, 3.18.
4.2.30. 5-Hydroxy-3-(4-hydroxyphenyl)-7-
(4-(4-methylpiperazin-1-yl)butoxy)-4H-chromen-4-one (5g)
To a solution of 2c (0.40 g, 1 mmol) in 5 mL of anhydrous
DMF was added 1-methyl-piperazine (0.50 g, 5 mmol), fol-
lowed by heating at 80 ꢁC for 1 h until the starting material
disappeared. To the reaction mixture was added ice water,
dropwise. The mixture was filtered, washed with water, dried
over Na2SO4 and concentrated. The residue was purified with
a silica gel column and was eluted with CH2Cl2/CH3OH 9:1 to
4.2.27. 5-Hydroxy-3-(4-hydroxyphenyl)-7-
(4-(piperazin-1-yl)butoxy)-4H-chromen-4-one (5d)
To a solution of 2c (0.40 g, 1 mmol) in 5 mL of anhydrous
DMF was added piperazine (0.43 g, 5 mmol), followed by
heating at 80 ꢁC for 1 h until the starting material disappeared.
To the reaction mixture was added ice water, dropwise. The
mixture was filtered, washed with water, dried over Na2SO4
and concentrated. The residue was purified with a silica gel
column and was eluted with CH2Cl2/CH3OH 9:1 to afford
1
afford 5g (0.36 g, 85%), mp: 140 ꢁC. H NMR (DMSO-d6):
1.54 (m, 2H), 1.70 (m, 2H), 2.12 (s, 3H), 2.26e2.31 (m,
8H), 2.50 (overlapped with solvent, 2H), 4.08 (t, J ¼ 6.5 Hz,
2H), 6.39 (d, J ¼ 2.0 Hz, 1H), 6.64 (d, J ¼ 2.0 Hz, 1H), 6.82
(d, J ¼ 8.5 Hz, 2H), 7.38 (d, J ¼ 8.5 Hz, 2H), 8.39 (s, 1H),
9.61 (s, 1H), 12.92 (s, 1H). ESI-MS C24H28N2O5 [M þ H]þ
425. Anal. Calcd for C24H28N2O5: C, 67.91; H, 6.65; N,
6.60. Found: C, 67.85; H, 6.69; N, 6.68.
1
5d (0.31 g, 75%), mp: 170e171 ꢁC. H NMR (DMSO-d6):
1.54 (m, 2H), 1.72 (m, 2H), 2.24e2.27 (m, 6H), 2.66 (m,
4H), 4.09 (t, J ¼ 6.3 Hz, 2H), 6.39 (d, J ¼ 2.0 Hz, 1H), 6.64
(d, J ¼ 2.0 Hz, 1H), 6.80 (d, J ¼ 8.5 Hz, 2H), 7.38 (d, J ¼
8.5 Hz, 2H), 8.40 (s, 1H), 9.61 (s, 1H), 12.95 (s, 1H). ESI-
MS C23H26N2O5 [M þ H]þ 411. Anal. Calcd for C23H26
N2O5: C, 67.30; H, 6.38; N, 6.82. Found: C, 67.20; H, 6.40;
N, 6.85.
4.2.31. 7-(4-(Furan-2-yl-methylamino)butoxy)-5-
hydroxy-3-(4-hydroxyphenyl)-4H-chromen-4-one (5h)
To a solution of 2c (0.40 g, 1 mmol) in 5 mL of anhydrous
DMF was added 2-furan-2-yl-methylamine (0.49 g, 5 mmol),
followed by heating at 80 ꢁC for 1 h until the starting material
disappeared. To the reaction mixture was added ice water,
dropwise. The mixture was filtered, washed with water, dried
over Na2SO4 and concentrated. The residue was purified with
a silica gel column and was eluted with CH2Cl2/CH3OH 9:1 to
4.2.28. 7-(4-(Dipropylamino)butoxy)-5-
hydroxy-3-(4-hydroxyphenyl)-4H-chromen-4-one (5e)
To a solution of 2c (0.40 g, 1 mmol) in 5 mL of anhydrous
DMF was added dipropylamine (0.51 g, 5 mmol), followed by
heating at 80 ꢁC for 1 h until the starting material disappeared.
To the reaction mixture was added ice water, dropwise. The
mixture was filtered, washed with water, dried over Na2SO4
and concentrated. The residue was purified with a silica gel
column and was eluted with CH2Cl2/CH3OH 9:1 to afford
1
afford 5h (0.31 g, 74%), mp: 121 ꢁC. H NMR (DMSO-d6):
1.54 (m, 2H), 1.72 (m, 2H), 2.50 (overlapped with solvent,
2H), 3.64 (s, 2H), 4.07 (t, J ¼ 6.5 Hz, 2H), 6.22 (d, J ¼
2.0 Hz, 1H), 6.38 (m, 2H), 6.62 (d, J ¼ 2.0 Hz, 1H), 6.82 (d,
J ¼ 8.5 Hz, 2H), 7.38 (d, J ¼ 8.5 Hz, 2H), 7.52 (m, 1H), 8.37
(s, 1H), 9.60 (s, 1H), 12.93 (s, 1H). ESI-MS C24H23NO6
[M þ H]þ 422. Anal. Calcd for C24H23NO6: C, 68.40; H,
5.50; N, 3.32. Found: C, 68.47; H, 5.53; N, 3.28.
1
5e (0.34 g, 80%), mp: 132 ꢁC. H NMR (DMSO-d6): 0.82 (t,
J ¼ 7.2 Hz, 6H), 1.35 (m, 4H), 1.50 (m, 2H), 1.70 (m, 2H),
2.28 (t, J ¼ 7.0 Hz, 4H), 2.37 (t, J ¼ 6.9 Hz, 2H), 4.06 (t, J ¼
6.5 Hz, 2H), 6.37 (d, J ¼ 2.0 Hz, 1H), 6.62 (d, J ¼ 2.0 Hz, 1H),
6.80 (d, J ¼ 8.5 Hz, 2H), 7.36 (d, J ¼ 8.5 Hz, 2H), 8.40 (s,
1H), 9.61 (s, 1H), 12.92 (s, 1H). ESI-MS C25H31NO5
[M þ H]þ 426. Anal. Calcd for C25H31NO5: C, 70.57; H,
7.34; N, 3.29. Found: C, 70.60; H, 7.30; N, 3.37.
4.2.32. 7-(4-(1H-Imidazol-1-yl)butoxy)-5-hydroxy-3-
(4-hydroxyphenyl)-4H-chromen-4-one (5i)
To a solution of 2c (0.40 g, 1 mmol) in 20 mL of dioxane
was added imidazole (0.41 g, 6 mmol), followed by heating
at reflux for 12 h until the starting material disappeared. To
the reaction mixture was added ice water, dropwise. The mix-
ture was filtered, washed with water, dried over Na2SO4 and
concentrated. The residue was purified with a silica gel
column and was eluted with CH2Cl2/CH3OH 9:1 to afford 5i
4.2.29. 7-(4-(Dibutylamino)butoxy)-5-
hydroxy-3-(4-hydroxyphenyl)-4H-chromen-4-one (5f)
To a solution of 2c (0.40 g, 1 mmol) in 5 mL of anhydrous
DMF was added dibutylamine (0.65 g, 5 mmol), followed by
heating at 80 ꢁC for 1 h until the starting material disappeared.
To the reaction mixture was added ice water, dropwise. The
mixture was filtered, washed with water, dried over Na2SO4
and concentrated. The residue was purified with a silica gel
column and was eluted with CH2Cl2/CH3OH 9:1 to afford 5f
(0.37 g, 82%), mp: 108 ꢁC. 1H NMR (DMSO-d6): 0.88 (t,
J ¼ 7.2 Hz, 6H), 1.30 (m, 4H), 1.58 (m, 4H), 1.77 (m, 4H),
3.00 (m, 4H), 3.09 (m, 2H), 4.11 (t, J ¼ 6.5 Hz, 2H), 6.39
1
(0.24 g, 62%), mp: 234 ꢁC. H NMR (DMSO-d6): 1.63 (m, 2H),
1.83 (m, 2H), 4.01 (t, J ¼ 6.2 Hz, 2H), 4.07 (t, J ¼ 6.5 Hz,
2H), 6.37 (d, J ¼ 2.0 Hz, 1H), 6.61 (d, J ¼ 2.0 Hz, 1H), 6.80
(d, J ¼ 8.5 Hz, 2H), 6.88 (br s, 1H), 7.18 (br s, 1H), 7.37 (d,
J ¼ 8.5 Hz, 2H), 7.64 (br s, 1H), 8.37 (s, 1H), 9.60 (s, 1H),
12.93 (s, 1H). ESI-MS C22H20N2O5 [M þ H]þ 393. Anal.

L.-N. Zhang et al. / European Journal of Medicinal Chemistry 43 (2008) 1543e1551
1551
Calcd for C22H20N2O5: C, 67.34; H, 5.14; N, 7.14. Found: C,
67.40; H, 5.21; N, 7.06.
isopropanol containing 5% 1 mol/L HCl was added to extract
the dye. After 12 h of incubation at room temperature, the op-
tical density (OD) was measured with a microplate reader at
550 nm. The observed MICs are presented in Table 1.
4.2.33. 7-(4-(1H-benzimidazolium-1-yl)butoxy)-
5-hydroxy-3-(4-hydroxyphenyl)-4H-chromen-4-one (5j)
To a solution of 2c (0.40 g, 1 mmol) in 20 mL of dioxane
was added benzoimidazole (0.71 g, 6 mmol), followed by
heating at reflux for 24 h until the starting material disap-
peared. To the reaction mixture was added ice water, dropwise.
The mixture was filtered, washed with water, dried over
Na2SO4 and concentrated. The residue was purified with a sil-
ica gel column and was eluted with CH2Cl2/CH3OH 9:1 to
Acknowledgement
The work was financed by grants (Projects 30772627 &
30672516) from National Natural Science Foundation of
China.
References
1
afford 5j (0.36 g, 81%), mp: 261 ꢁC. H NMR (DMSO-d6):
2.28 (m, 2H), 2.50 (overlapped with solvent, 2H), 4.02 (t,
J ¼ 6.2 Hz, 2H), 4.07 (t, J ¼ 6.5 Hz, 2H), 6.36 (d, J ¼
2.0 Hz, 1H), 6.58 (d, J ¼ 2.0 Hz, 1H), 6.81 (d, J ¼ 8.5 Hz,
2H), 7.19e7.25 (m, 2H), 7.38 (d, J ¼ 8.5 Hz, 2H), 7.60e
7.65 (m, 2H), 8.23 (s, 1H), 8.38 (s, 1H), 9.60 (s, 1H), 12.93
(s, 1H). ESI-MS C26H22N2O5 [M þ H]þ 443. Anal. Calcd
for C26H22N2O5: C, 70.58; H, 5.01; N, 6.33. Found: C,
70.65; H, 4.92; N, 6.35.
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