Synthesis, crystal structure and antimicrobial activity of deoxybenzoin derivatives from genistein

Article abstract of DOI:10.1016/j.ejmech.2007.05.013

A series of deoxybenzoin derivatives from genistein were synthesized and their structures were elucidated by ¹H NMR, mass spectral data and micro analyses. The structures of 2, 7 and 10 were determined by single-crystal X-ray analysis. These obtained compounds were evaluated for their assayed antibacterial (Bacillus subtilis, Escherichia coli, Pseudomonas fluorescence and Staphylococcus aureus) and antifungal (Aspergillus niger, Candida albicans and Trichophyton rubrum) activities by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide) method. Most compounds have displayed comparable antibacterial activity against bacterial. On the basis of the biological results, structure-activity relationships are discussed.

Full text of DOI:10.1016/j.ejmech.2007.05.013

Available online at www.sciencedirect.com
European Journal of Medicinal Chemistry 43 (2008) 662e667
http://www.elsevier.com/locate/ejmech
Short communication
Synthesis, crystal structure and antimicrobial activity
of deoxybenzoin derivatives from genistein
*
Huan-Qiu Li, Jia-Yu Xue, Lei Shi, Shan-Ying Gui, Hai-Liang Zhu
Institute of Functional Biomolecules, State Key Laboratory of Pharmaceutical Biotechnology,
Nanjing University, Nanjing 210093, People’s Republic of China
Received 13 March 2007; received in revised form 11 May 2007; accepted 24 May 2007
Available online 8 June 2007
Abstract
1
A series of deoxybenzoin derivatives from genistein were synthesized and their structures were elucidated by H NMR, mass spectral data
and micro analyses. The structures of 2, 7 and 10 were determined by single-crystal X-ray analysis. These obtained compounds were evaluated
for their assayed antibacterial (Bacillus subtilis, Escherichia coli, Pseudomonas fluorescence and Staphylococcus aureus) and antifungal (Asper-
gillus niger, Candida albicans and Trichophyton rubrum) activities by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide)
method. Most compounds have displayed comparable antibacterial activity against bacterial. On the basis of the biological results, struc-
tureeactivity relationships are discussed.
Ó 2007 Elsevier Masson SAS. All rights reserved.
Keywords: Deoxybenzoin derivatives; Metal complexes; Antibacterial activity; Structureeactivity relationships
1. Introduction
biologically active genistein derivatives [17,18]. In this paper,
genistein was first used as the starting material to synthesize
deoxybenzoins in high yield through a convenient ring-break-
ing method. For further analytical and biological investiga-
tions, novel dimeric deoxybenzoin derivatives and transition
metal complexes were also prepared to study their in vitro an-
tibacterial activity against Bacillus subtilis, Escherichia coli,
Pseudomonas fluorescence and Staphylococcus aureus.
The rapid development of pathogen resistance to most of
the known antibiotics is becoming a serious health problem
[1e3]. Therefore, the development of new and different anti-
microbial drugs is a very important objective and much of
the research program efforts are directed towards the design
of new agents [4e7]. Genistein (5,7-dihydroxy-3-(4-hydroxy-
phenyl)-4H-1-benzopyran-4-one, GEN, 1) is the most abun-
dant isoflavone which has demonstrated potent biological
activity such as anticarcinogenic [8], anti-inflammatory [9],
antiviral [10], anti-protozoal [11] and estrogen receptor [12].
As important derivatives of isoflavones, deoxybenzoins also
exhibited estrogenicity [13] and antimicrobial activities [14].
During recent years coordination compounds of biologically
active ligands [15,16] have received much attention, and our
interest in this area is to design and synthesize diverse
2. Chemistry
Compounds 2e14 were synthesized for antimicrobial activ-
ity screening, and the synthetic methods adopted for preparing
compounds 2e14 are illustrated in Schemes 1 and 2. The hy-
droxy groups on the aromatic rings of genistein were first pro-
tected by means of nucleophilic displacement (step a).
Treating the obtained compounds 1ae1e with 10%
aq NaOH and acidified by 30% aq HCl for 17e19 h gave
deoxybenzoins 2e6 (step b). This two-step ring-cleavage reac-
tion was carried out as a one-pot reaction so that it was a con-
venient method to obtain deoxybenzoins and their derivatives
* Corresponding author. Tel.: þ86 25 8359 2572; 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.2007.05.013

H.-Q. Li et al. / European Journal of Medicinal Chemistry 43 (2008) 662e667
663
HO
O
RO
OH
RO
O
O
b
a
OH
O
OR
O
OR
OH
OR
OR
1
1a : R = Me
1b : R = H
2 : R = Me
3 : R = H
1c : R = C2H5OOCCH2
1d : R = BrCH2CH2
4 : R = HOOCCH2
5 : R = BrCH2CH2
6 : R = BrCH2CH2CH2
1e : R = BrCH2CH2CH2
OR
OR
O
RO
OH
OH
OR
c
RO
O
OR
7 : R = Me
8 : R = HOOCCH2
9 : R = BrCH2CH2CH2
Scheme 1. Syntheses of compounds 2e9. Reagents: (a) 1a e dimethyl sulfate/NaOH/H2O, 1c e benzyl bromide/K2CO3, 1d e 1,2-dibromoethane/K2CO3,
1e e 1,3-dibromopropane/K2CO3; (b) 10% aq NaOH; (c) formaldehyde/HCl.
in high yield. Thus, starting from the obtained deoxybenzoins
2e6, novel dimeric derivatives 7e9 (Scheme 1) were prepared
by FriedeleCrafts reaction (step c), while working with form-
aldehyde in a strong acid media [19].
3. Results and discussion
3.1. Crystal structures of compounds 2, 7 and 10
The deoxybenzoin ligand 2, on refluxing with copper ace-
tate, nickel acetate, cobalt acetate, zinc acetate and manganese
acetate in acetonitrile solution, in (2:1) molar ratio, yielded
corresponding complexes 10e14, respectively. The products
formed were filtered, washed with warm water, ethanol and
dried under reduced pressure in a vacuum desiccator contain-
ing anhydrous CaCl2. On the basis of elemental analysis, li-
gand stoichiometry to the metal of 2:1 has been proposed
for these complexes. The proposed structure (Scheme 2) for
these complexes has the support of IR and UV spectra. The
complexes along with their characteristics are recorded in
Table 1, their UV spectra in Table 2 and their IR spectra in
Table 3.
The crystal structure of 2 is illustrated in Fig. 1, 2 crystal-
lizes in the monoclinic, space group P21/n with unit cell
˚
˚
˚
parameters: a ¼ 4.8350(10) A, b ¼ 11.429(2) A, c ¼ 27.415(6) A,
3
ꢀ
˚
b ¼ 90.63(3) , V ¼ 1514.8(5) A , Z ¼ 4. There is a strong intra-
molecular OeH/O hydrogen boꢀnd between O4 and O2
˚
(O4—H4A/O2, 2.465(3) A, 148.5 ) in the structure.
The crystal structure of 7 is illustrated in Fig. 2, 7 crystal-
lizes in the triclinic, space group P1 with the following crys-
˚
˚
ꢀ
tallographic parameters: a ¼ 10.107(2) A, b ¼ 11.350(2) A,
ꢀ
ꢀ
˚
c ¼ 14.090(3) A, a ¼ 73.16(3) , b ¼ 81.07(3) , g ¼ 80.16(3) ,
3
˚
V ¼ 1514.6(5) A , Z ¼ 2. There exists both intra and intermo-
lecular hydrogen interactions in the crystal structure. In each
molecule, there are two intramolecular O—H/O hydrogen
OMe
OMe
MeO
OH
d
O
O
OMe
O
O
MeO
M
OMe
O
OMe
O
O
OMe
MeO
2
10 : M = Cu
11 : M = Ni
12 : M = Co
13 : M = Zn
14 : M = Mn
Scheme 2. Syntheses of complexes 10e14.

664
H.-Q. Li et al. / European Journal of Medicinal Chemistry 43 (2008) 662e667
Table 1
Data of color and elemental analysis of the complexes
Complex
Color
Molecular formula
Data of mature (data of theory) (%)
C
H
N
10
11
12
13
14
Green
Purple
Red
Cu(C17H16O6)2CNCH3
Ni(C17H16O6)2
Co(C17H16O6)2
58.65 (58.53)
59.07 (59.01)
59.05 (58.86)
58.50 (58.38)
59.39 (59.33)
4.79 (4.67)
4.67 (4.58)
4.66 (4.61)
4.62 (4.55)
4.69 (4.53)
1.91 (1.80)
0
0
0
0
White
Brown
Zn(C17H16O6)2
Mn(C17H16O6)2
ꢀ
˚
bonds (O3eH3/O2, 2.482(4) A, 147.4 and O15eH15/O1,
Zhuyan Biotechnology Co. Ltd, Amresco 060D0504, Nanjing
210002, China) and penicillin (North China Pharmaceutical
Co. Ltd, D0211107, Hebei 050015, China). All synthesized
compounds were found to be inactive against the tested fungi
strains. Compounds 3e9 showed antimicrobial activity against
B. subtilis and E. coli at the values of 12.5e50 mg/ml. Com-
pound 9 displayed potent acitivity with an MIC value of
6.25 mg/ml against B. subtilis, which was comparable to the
positive control penicillin. Dimeric 7e9 were all found to be
more active than other deoxybenzoins, implying the dimeric
derivative may be a new therapy agent of antibiotics.
Complexes 10e14 also showed antimicrobial activity
against S. aureus with MIC values at 10.5e50 mg/ml, but
they were completely inactive against B. subtilis and E. coli.
Complex Ni(2)2 (11) exhibited potent activity against
S. aureus with an MIC value of 10.5 mg/ml, while Co(2)2
(12) and Zn(3)2 (13) showed moderate activities against S. au-
reus (22.5 and 18.5 mg/ml). The activities of these compounds
were also compared with the two antibiotics kanamycin and
penicillin, and some of them exhibited similar antibacterial
activities with commercial antibiotics. Compounds 1e14
were also tested against A. niger, C. albicans and T. rubrum
and they had no antifungal activity.
ꢀ
˚
2.458(4) A, 149.1 ). And these hydrogen bonds result in sig-
˚
nificant elongations of the O(2)]C(27) bond (1.239(4) A)
˚
and O(1)]C(15) bond (1.250(5) A) compared to normal
C]O bond. The intermolecular interaction is O3—H3/
O10#1 (3.102(4) A and 122.8 ), with symmetry code #1:
ꢁx þ 1, ꢁy, ꢁz þ 1. In the crystal structure, the molecules
are linked by intermolecular hydrogen bonds forming
a three-dimensional network.
ꢀ
˚
The crystal structure of Cu complex 10 is illustrated in
Fig. 3, 10 also belongs to tricilinic, space group P1 with
the following crystallographic parameters: a ¼ 8.549
A, b ¼ 14.736 A, c ¼ 15.200 A, a ¼ 64.12ꢀ, b ¼ 85.75ꢀ,
˚
˚
˚
3
ꢀ
˚
g ¼ 88.87 , V ¼ 1717.9 A , Z ¼ 2. The molecular structure
of compound 10 consists of
a
mononuclear [Cu
(C17H16O6)2CNCH3] molecule and an uncoordinated acetoni-
trile molecule. The Cu atom is in a square-planar geometry
and is four-coordinated by four O atoms from two deoxyben-
zoin ligands. The distances between Cu—O4 (1.922(5) A),
˚
Cu—O5 (1.914(5) A), Cu—O6 (1.936(5) A) and Cu—O7
˚
˚
˚
(1.901(5) A) are comparable with the values found in most
copper(II) complexes [20]. The four coordinating atoms
around the central metal atom are approximately coplanar,
giving a square-planar geometry with an average deviation
of 0.0549 A, with the Cu atom 0.037(3) A above this plane.
An unexpected detail in structure of 10 was that both meth-
ylenes of deoxybenzoins were oxidized to two carbonyl
groups before ligation to the Cu ion. When the hydroxyl group
of 2 was protected, the methylene group in the deoxybenzoins
was easily oxygenized in the air. It could be deduced that com-
plex 10 was formed and then oxidized prior to crystallization.
According to structureeactivity relationships (SAR), it can
be concluded that dimeric deoxybenzoin derivatives from gen-
istein (7e9) are generally more active than genistein and
deoxybenzoins 2e6 against selected microorganisms. Addi-
tionally, the organic-metal complexes 10e14 of deoxyben-
zoins have potential antimicrobial activity and deserve
further investigation.
˚
˚
4. Experimental protocols
3.2. In vitro antibacterial assay
4.1. General
All the synthesized compounds were screened for their
antibacterial (B. subtilis, E. coli, P. fluorescence and S. aureus)
and antifungal (Aspergillus niger, Candida albicans and
Trichophyton rubrum) activities by MTT (3-(4,5-dimethylthia-
zol-2-yl)-2,5-diphenyl trtrazolium bromide) method. The
MICs (minimum inhibitory concentrations) of the compounds
against four bacterias are presented in Table 4. Also included
is the activity of reference compounds kanamycin (Nanjing
1,2-Dibromoethane, 1,3-dibromopropane, triethylamine,
mercaptoethanol, the metal salts copper acetate, nickel acetate,
cobalt acetate, zinc acetate and manganese acetate were
Table 3
IR spectra of the ligand and the complexes (cmꢁ1
)
Compound
nC]O
nCeO
10
11
12
13
14
1625
1611
1618
1637
1608
1149
1152
1146
1178
1148
Table 2
UV spectra of the ligand and the complexes (nm)
Compound
Bands (nm)
10
11
12
13
14
326
373
380
374
382

H.-Q. Li et al. / European Journal of Medicinal Chemistry 43 (2008) 662e667
665
Fig. 1. Crystal structure of 2.
Fig. 3. Crystal structure of 10.
purchased from Shanghai Chemical Reagent Company
(Shanghai, China), and were used as received without purifica-
tion. Genistein (>96%) was purchased from Shanxi Huike
Botanical Development Co. Ltd. Reactions and the resulted
products were monitored by thin-layer chromatography
(TLC), and were run on the silica gel coated aluminum sheets
(silica gel 60 GF254, E. Merck, Germany) and visualized in
UV light (254 nm). Sonication was performed in a Kunshan
KQ 500E ultrasonic cleaner (Jiangsu, China) with irradiation
delivered at 40 kHz and 500 W. All the NMR spectra were
recorded on a Bruker DRX 500 or DPX 300 model spectrom-
4.2. Syntheses
1-(2-Hydroxy-4,6-dimethoxyphenyl)-2-(4-methoxyphenyl)e-
thanone (2) genistein(8.1 g, 30 mmol) wasdissolvedin100 mlof
15% NaOH, then dimethyl sulfate (13.5 ml, 100 mmol) was care-
fully added portionwise over 30 min after cooling in an ice bath,
and the resulting solution was stirred at 25 ꢀC for 6 h and then fil-
tered. Without further purifying, 50 ml 10% NaOH solution was
added, the reaction mixture was stirred for 17e19 h at 80 ꢀC, fil-
teredonsand. ThefiltrateisneutralizedwithaHClsolution(30%)
to pH 7 and then extracted with AcOEt (3 ꢂ 30 ml). The com-
bined organic extracts were dried over anhydrous sodium sulfate,
obtained 2 as colorless crystal. M.p. 147e149 ꢀC; yield: 85%; 1H
NMR (500 MHz, DMSO-d6): 3.7 (s, 3H); 3.8 (s, 3H); 3.9 (s, 3H);
4.2 (s, 2H); 6.1 (d, J ¼ 2.0, 1H); 6.2 (d, J ¼ 2.0, 1H); 6.8 (d,
J ¼ 8.5, 2H); 7.1 (d, J ¼ 8.5, 2H); 13.4 (s, 1H). MS (ESI)
C17H18O5 [M þ H]þ 303.3. Anal. Calcd for C17H18O5: C,
67.55; H, 5.96%. Found: C, 67.43; H, 5.88%.
1
eter in DMSO-d6. Chemical shifts (d) for H NMR spectra
were reported in parts per million to residual solvent protons.
Melting points were measured on a Boetius micro melting
point apparatus. The ESI-MS spectra were recorded on a Mar-
iner System 5304 Mass Spectrometer.
Table 4
Antimicrobial activity of the synthesized compounds
Compound
Minimum inhibitory concentration (mg/ml)
Bacillus
subtilis
Escherichia
coli
Pseudomonas
fluorescence
Staphylococcus
aureus
1
>50
>50
40.5
45.5
30.5
25.0
31.5
12.5
6.25
>50
>50
>50
>50
>50
>50
1
>50
>50
42.5
48.5
36.5
25.0
38.5
25.0
17.5
>50
>50
>50
>50
>50
>50
0.45
>50
>50
>50
>50
>50
>50
>50
>50
>50
>50
>50
>50
>50
>50
>50
>50
3.9
>50
>50
>50
>50
>50
>50
>50
>50
>50
40.5
10.5
22.5
18.5
>50
>50
1
2
3
4
5
6
7
8
9
10
11
12
13
14
Ketoconazole
Kanamycin
Penicillin
7.8
>50
2
Fig. 2. Crystal structure of 7.

666
H.-Q. Li et al. / European Journal of Medicinal Chemistry 43 (2008) 662e667
4.2.1. 2-(4-Hydroxyphenyl)-1-(2,4,6-trihydroxyphenyl)
ethanone (3)
4.2.4. 1-(2,4-Bis(3-bromopropoxy)-6-hydroxyphenyl)-2-
(4-(3-bromopropoxy)phenyl)ethanone (6)
Genistein (2.7 g, 10 mmol) was dissolved in 40 ml of 10%
NaOH, under nitrogen, the reaction mixture was stirred for
17e19 h at 60 ꢀC, filtered on sand. The filtrate is neutralized
with a HCl solution (30%) to pH 7 and then extracted with
AcOEt (3 ꢂ 30 ml). The combined organic extracts were dried
over anhydrous sodium sulfate, obtained 3 as yellow powder.
Genistein (2.7 g, 10 mmol) was added to a mixture contain-
ing potassium carbonate (2.0 g, 15 mmol) and anhydrous
DMF (15 ml), and this solution was stirred at 60 ꢀC. Then di-
bromopropane (5.1 g, 25 mmol) was carefully added to the
above solution in 15 min, and the resulting solution was stirred
at 60 ꢀC for 4.5 h and cooled, and 30 ml of water was added
and filtered. Without further purifying, 50 ml 10% NaOH
solution was added, the reaction mixture was stirred for 17e
19 h at 80 ꢀC, filtered on sand. The filtrate neutralized with
HCl solution (30%) to pH 7 and then extracted with AcOEt
(3 ꢂ 30 ml). The combined organic extracts were dried over
anhydrous sodium sulfate, obtained 6 as white powder. M.p.
142e146 ꢀC; yield: 67%; 1H NMR (300 MHz, DMSO-d6):
2.1e2.2 (overlapped multiplets, 6H); 3.5e3.7 (overlapped
multiplets, 6H); 4.1 (s, 2H); 4.5e4.6 (overlapped multiplets,
6H); 6.2 (d, J ¼ 2.0, 1H); 6.2 (d, J ¼ 2.0, 1H); 6.8 (d,
J ¼ 8.5, 2H); 7.1 (d, J ¼ 8.5, 2H); 13.1 (s, 1H). MS (ESI)
1
M.p. 157e159 ꢀC; yield: 65%; H NMR (300 MHz, DMSO-
d6): 4.2 (s, 2H); 5.8 (s, 2H); 6.6 (d, J ¼ 8.4, 2H); 7.0 (d,
J ¼ 8.4, 2H); 9.1 (s, 1H); 10.3 (s, 1H); 12.2 (s, 2H). MS
(ESI) C14H12O5 [M þ H]þ 261.1. Anal. Calcd for C14H12O5:
C, 64.61; H, 4.65%. Found: C, 64.84; H, 4.34%.
4.2.2. 2,20-(4-(2-(4-(Carboxymethoxy)phenyl)acetyl)-5-
hydroxy-1,3-phenylene)bis(oxy)diacetic acid (4)
Genistein (2.7 g, 10 mmol) was added to a mixture contain-
ing potassium carbonate (2.0 g, 15 mmol) and anhydrous
DMF (15 ml), and this solution was stirred at 60 ꢀC. Then
ethyl bromoacetate (5.0 g, 30 mmol) was carefully added to
the above solution in 15 min, and the resulting solution was
stirred at 60 ꢀC for 4.5 h and cooled, and 30 ml of water
was added and filtered. Without further purifying, 50 ml
10% NaOH solution was added, the reaction mixture was
stirred for 17e19 h at 80 ꢀC, filtered on sand. The filtrate is
neutralized with a HCl solution (30%) to pH 7 and then
extracted with AcOEt (3 ꢂ 30 ml). The combined organic ex-
tracts were dried over anhydrous sodium sulfate, obtained 4 as
white powder. M.p. 236e238 ꢀC; yield: 50%; 1H NMR
(300 MHz, DMSO-d6): 4.3 (s, 2H); 4.6 (s, 2H); 4.6 (s, 2H);
4.8 (s, 2H); 6.0 (d, J ¼ 2.0, 1H); 6.1 (d, J ¼ 2.0, 1H); 6.6 (d,
J ¼ 8.5, 2H); 7.0 (d, J ¼ 8.5, 2H); 12.8 (s, 2H); 13.1 (s, 1H).
MS (ESI) C20H18O11 [M þ H]þ 435.1. Anal. Calcd for
C20H18O11: C, 55.30; H, 4.18%. Found: C, 55.64; H, 4.34%.
C23H27Br3O5
[M þ H]þ
624.1.
Anal.
Calcd
for
C23H27Br3O5: C, 44.33; H, 4.37; Br, 38.47%. Found: C,
44.15; H, 4.54; Br, 38.19%.
4.2.5.
1,10-[3,30-Methylenebis(2-hydroxy-4,6-dimethoxy-
3,1-phenylene)]bis[2-(4-methoxyphenyl)ethanone] (7)
Deoxybenzoin 2 (0.2 g, 0.8 mmol) was added to a mixture
containing HCl (3 ml) and ethanol (20 ml), and this solution
was stirred at 60 ꢀC for 15 min and then HCHO (3 ml) was
carefully added to the above solution in 15 min, and the result-
ing solution was refluxed for 12 h and then filtered, gave
a white solid, recrystallization of the solid from 15 ml acetone
gave compound 7 as clear crystals. M.p. 151e153 ꢀC; yield:
1
78%; H NMR (300 MHz, DMSO-d6): 3.6 (s, 2H); 3.7 (s,
3H); 3.8 (s, 3H); 3.9 (s, 3H); 4.1 (s, 2H); 6.1 (s, 1H); 6.8 (d,
J ¼ 8.4, 2H); 7.1 (d, J ¼ 8.4, 2H); 13.6 (s, 1H). MS (ESI)
C35H36O10 [M þ H]þ 517.6. Anal. Calcd for C35H36O10: C,
41.34; H, 3.64%. Found: C, 41.13; H, 3.47%.
4.2.3. 1-(2,4-Bis(2-bromoethoxy)-6-hydroxyphenyl)
-2-(4-(2-bromoethoxy)phenyl)ethanone (5)
Compounds 7e9 were prepared in analogy.
Genistein (2.7 g, 10 mmol) was added to a mixture contain-
ing potassium carbonate (2.0 g, 15 mmol) and anhydrous
DMF (15 ml), and this solution was stirred at 60 ꢀC. Then di-
bromoethane (9.4 g, 50 mmol) was carefully added to the
above solution in 15 min, and the resulting solution was stirred
at 60 ꢀC for 4.5 h and cooled, and 30 ml of water was added
and filtered. Without further purifying, 50 ml 10% NaOH
solution was added, the reaction mixture was stirred for 17e
19 h at 80 ꢀC, filtered on sand. The filtrate was neutralized
with a HCl solution (30%) to pH 7 and then extracted with
AcOEt (3 ꢂ 30 ml). The combined organic extracts were dried
over anhydrous sodium sulfate, obtained 5 as white powder.
4.2.6. 2,20-(4-(6-(Carboxymethoxy)-3-(2-(4-
(carboxymethoxy)phenyl)acetyl)-4-(carboxyperoxy)-2-
hydroxybenzyl)-6-(2-(4-(carboxymethoxy)phenyl)acetyl)-5-
hydroxy-1,3-phenylene)bis(oxy)diacetic acid (8)
M.p. 212e214 ꢀC; yield: 70%; 1H NMR (300 MHz,
DMSO-d6): 3.8 (s, 2H); 4.3 (s, 2H); 4.6 (s, 2H); 4.7 (s, 2H);
4.8 (s, 2H); 6.0 (d, J ¼ 2.0, 1H); 6.1 (d, J ¼ 2.0, 1H); 6.7 (d,
J ¼ 8.5, 2H); 7.1 (d, J ¼ 8.5, 2H); 11.0 (s, 1H); 12.8 (s, 2H);
13.2 (s, 1H). MS (ESI) C41H36O24 [M þ H]þ 805.2. Anal.
Calcd for C41H36O24: C, 46.34; H, 7.64%. Found: C, 46.51;
H, 7.48%.
1
M.p. 186e188 ꢀC; yield: 70%; H NMR (300 MHz, DMSO-
d6): 3.7e3.9 (overlapped multiplets, 6H); 4.1 (s, 2H); 4.3e
4.4 (overlapped multiplets, 6H); 6.1 (d, J ¼ 2.0, 1H); 6.1 (d,
J ¼ 2.0, 1H); 6.8 (d, J ¼ 8.5, 2H); 7.1 (d, J ¼ 8.5, 2H); 12.4
(s, 1H). MS (ESI) C20H21Br3O5 [M þ H]þ 582.1. Anal. Calcd
for C20H21Br3O5: C, 41.34; H, 3.64; Br, 41.25%. Found: C,
41.56; H, 3.35; Br, 41.41%.
4.2.7. 1-(3-(4,6-Bis(3-bromopropoxy)-3-(2-
(4-(3-bromopropoxy)phenyl)acetyl)-2-hydroxybenzyl)-4-
(4-bromobutoxy)-6-(3-bromopropoxy)-2-hydroxyphenyl)-2-
(4-(3-bromopropoxy)phenyl)ethanone (9)
M.p. 115e117 ꢀC; yield: 70%; 1H NMR (300 MHz,
DMSO-d6): 2.1e2.2 (overlapped multiplets, 6H); 3.6e3.7

H.-Q. Li et al. / European Journal of Medicinal Chemistry 43 (2008) 662e667
667
(overlapped multiplets, 6H); 3.8 (s, 2H); 4.1 (s, 2H); 4.6e4.7
(overlapped multiplets, 6H); 6.2 (d, J ¼ 2.0, 1H); 6.3 (d,
J ¼ 2.0, 1H); 6.8 (d, J ¼ 8.5, 2H); 7.1 (d, J ¼ 8.5, 2H); 13.1
(s, 1H). MS (ESI) C48H56Br6O10 [M þ H]þ 1273.1. Anal.
Calcd for C48H56 Br6O10: C, 41.34; H, 3.64%. Found: C,
41.87; H, 3.79%.
well. Incubation was continued at room temperature for
4e5 h. The content of each well was removed, and 100 mL
of isopropanol containing 5% 1 mol/L HCl was added to ex-
tract the dye. After 12 h of incubation at room temperature,
the optical density (OD) was measured with a microplate
reader at 550 nm.
Complexes 10e14 along with their characteristics and UV,
IR spectra are recorded in Table 2.
Acknowledgments
4.3. Crystallographic data
The work was supported by National Natural Science Foun-
dation of China (Project: 30672516), and by Analytical Test
Fund in Nanjing University for Dr. Hai-Liang Zhu.
Crystallographic data (excluding structure factors) for com-
pounds 2, 7 and 10 have been deposited with the Cambridge
Crystallographic Data Centre as supplementary publication
number CCDC 614278-614280. Copies of the data can be ob-
tained, free of charge, on application to CCDC, 12 Union
Road, Cambridge CB2 1EZ, UK [fax: þ44(0)-1223-336033
or e-mail: deposit@ccdc.cam.ac.uk].
References
[1] D.T.W. Chu, J.J. Plattner, L. Katz, J. Med. Chem. 39 (1996) 3853e3874.
[2] K.M. Overbye, J.F. Barrett, Drug Discov. Today 10 (2005) 45e52.
[3] C. Walsh, Nature 406 (2000) 775e781.
[4] J. Travis, Science 264 (1994) 360e362.
[5] L. Otvos Jr., J.D. Wade, F. Lin, B.A. Condie, J. Hanrieder, R. Hoffmann,
J. Med. Chem. 48 (2005) 5349.
4.4. Antimicrobial activity
The antibacterial activity of the synthesized compounds
was tested against B. subtilis, E. coli, P. fluorescence and
S. aureus using MH medium (MuellereHinton medium: ca-
sein hydrolysate 17.5 g, soluble starch 1.5 g, beef extract
1000 ml), the antifungal activity of the compounds was tested
against A. niger, C. albicans and T. rubrum using RPMI-1640
medium (RPMI-1640 (GIBCO BRL) 10 g, NaHCO3 2.0 g,
0.165 mol/L morpholinepropanesulfonic acid (MOPS)
(Sigma) (34.5 g), triple distilled water 900 ml, buffered to
pH 7.0 with 1 mol/L NaOH (25 ꢀC), metered volume to
1000 ml, filtered sterilization, conservation at 4 ꢀC). The
MICs of the test compounds were determined by a colorimetric
method using the dye MTT [21]. A stock solution of the syn-
thesized compound (50 mg/ml) in DMSO was prepared and
graded quantities of the test compounds were incorporated
in specified quantity of sterilized liquid medium (MH medium
for antibacterial activity and RPMI-1640 medium for antifun-
gal activity). A specified quantity of the medium containing
the compound was poured into microtitration plates. Suspen-
sion of the microorganism was prepared to contain approxi-
mately 105 cfu/ml and applied to microtitration plates with
serially diluted compounds in DMSO to be tested and incu-
bated at 37 ꢀC for 24 h and 48 h for bacterial and fungi,
respectively. After the MICs were visually determined on
each of the microtitration plates, 50 mL of PBS (Phosphate
Buffered Saline 0.01 mol/L, pH 7.4, Na2HPO4$12H2O 2.9 g,
KH2PO4 0.2 g, NaCl 8.0 g, KCl 0.2 g, distilled water
1000 ml) containing 2 mg of MTT/ml was added to each
[6] H. Xin, K.A. Reynolds, Antimicrob. Agents Chemother. 46 (2002)
1310e1318.
[7] Y. Cui, Y. Dang, Y. Yang, S. Zhang, R. Ji, Eur. J. Med. Chem. 40 (2005)
209e214.
[8] Z.M. Shao, J. Wu, Z.Z. Shen, S.H. Barsky, Cancer Res. 58 (21) (1998)
4851e4857.
[9] L. Sun, N. Tran, F. Tang, J. Med. Chem. 41 (1998) 2588e2593.
[10] V.K. Pandey, S. Tusi, Z. Tusi, R. Raghubir, M. Dixit, M.N. Joshi,
S.K. Bajpai, Indian J. Chem. B 43 (1) (2004) 180e183.
[11] A. Baliani, G.J. Bueno, M.L. Stewart, V. Yardley, R. Brun, M.P. Barrett,
I.H. Gilbert, J. Med. Chem. 48 (2005) 5570e5579.
[12] B.R. Henke, T.G. Consler, N. Go, R.L. Hale, D.R. Hohman, S.A. Jones,
A.T. Lu, L.B. Moore, J.T. Moore, L.A. Orband-Miller, R.G. Robinett,
J. Shearin, P.K. Spearing, E.L. Stewart, P.S. Turnbull, S.L. Weaver,
S.P. Williams, G.B. Wisely, M.H. Lambert, J. Med. Chem. 45 (2002)
5492e5505.
[13] N. Fokialakis, G. Lambrinidis, D.J. Mitsiou, N. Aligiannis, S. Mitakou,
A.L. Skaltsounis, H. Pratsinis, E. Mikros, M.N. Alexis, Chem. Biol. 11
(2004) 397e406.
[14] A.D. Richard, F. Daneel, Phytochemistry 60 (1998) 205e211.
[15] S. Renner, G. Schneider, Chem. Med. Chem. 1 (2006) 181e185.
[16] W.T.M. Mooij, M.J. Hartshorn, L.J. Tickle, A.J. Sharff, M.L. Verdonk,
H. Jhoti, Chem. Med. Chem. 1 (2006) 827e838.
[17] L. Shi, H.-M. Ge, S.-H. Tan, H.-Q. Li, Y.-C. Song, H.-L. Zhu,
R.-X. Tan, Eur. J. Med. Chem. 42 (2007) 558e564.
[18] H.-Q. Li, H.-M. Ge, Y.-X. Chen, C. Xu, L. Shi, H. Ding, H.-L. Zhu,
R.-X. Tan, Chem. Biodivers. 3 (2006) 463e471.
[19] N. Haddad, Y. Xu, J.A. Baron, K.Y. Nathan, Tetrahedron Lett. 43 (2002)
1135e1138.
[20] R.J. Butcher, G.M. Mockler, O. McKern, Acta Cryst. E59 (2003) 1104e
1106.
[21] J. Meletiadis, J.F. Meis, J.W. Mouton, J.P. Donnelly, P.E. Verweij, J. Clin.
Microbiol. 38 (2000) 2949e2954.