Evaluation of bactericidal and fungicidal activity of ferrocenyl or phenyl derivatives in the diphenyl butene series

Article abstract of DOI:10.1016/j.jorganchem.2010.09.015

Some ferrocene compounds, such as tamoxifen derivatives hydroxyferrocifen 1 and ferrociphenol 2, show strong antiproliferative activity on hormone-dependent and hormone-independent breast cancer cells. In order to evaluate their antimicrobial activity, they were tested, together with their purely organic analogs, on the bacteria Pseudomonas aeruginosa and Staphylococcus aureus and the fungus Candida albicans. It has been found that the compounds bearing alkylamino chains are active, and in these cases the antimicrobial activity increases for compounds bearing two amino chains. These dialkyamino compounds are equally as active as doxycycline on P. aeruginosa and S. aureus but superior to it on C. albicans. The results show that there are no general correlation between the antitumoral activity and the bactericidal and fungicidal activities of these compounds. The ferrocene derivatives and their organic analogs have similar activity on bacteria and fungus. This bactericidal and fungicidal behaviour is a novel area of activity for these entities.

Full text of DOI:10.1016/j.jorganchem.2010.09.015

Journal of Organometallic Chemistry 696 (2011) 1038e1048
Contents lists available at ScienceDirect
Journal of Organometallic Chemistry
journal homepage: www.elsevier.com/locate/jorganchem
Evaluation of bactericidal and fungicidal activity of ferrocenyl or phenyl
derivatives in the diphenyl butene series
,
,
b
c
c,
Mehdi El Arbi a b, Pascal Pigeon a, Siden Top a , Ali Rhouma , Sami Aifa , Ahmed Rebai
*
**
,
Anne Vessières a, Marie-Aude Plamont a, Gérard Jaouen a
a Chimie ParisTech (Ecole Nationale Supérieure de Chimie de Paris), Laboratoire Charles Friedel, UMR CNRS 7223, 11 rue Pierre et Marie Curie, 75231 Paris Cedex 05, France
b Unité de Recherche Protection des Plantes Cultivées et Environnement, Institut de l’olivier de Sfax, Route de Sokra Km 1,5 e 3003 Sfax, Tunisia
c Centre de Biotechnologie de Sfax, Route de Sidi Mansour Km 6 e BP 1177, 3018 Sfax, Tunisia
a r t i c l e i n f o
a b s t r a c t
Article history:
Some ferrocene compounds, such as tamoxifen derivatives hydroxyferrocifen 1 and ferrociphenol 2,
show strong antiproliferative activity on hormone-dependent and hormone-independent breast cancer
cells. In order to evaluate their antimicrobial activity, they were tested, together with their purely organic
analogs, on the bacteria Pseudomonas aeruginosa and Staphylococcus aureus and the fungus Candida
albicans. It has been found that the compounds bearing alkylamino chains are active, and in these cases
the antimicrobial activity increases for compounds bearing two amino chains. These dialkyamino
compounds are equally as active as doxycycline on P. aeruginosa and S. aureus but superior to it on C.
albicans. The results show that there are no general correlation between the antitumoral activity and the
bactericidal and fungicidal activities of these compounds. The ferrocene derivatives and their organic
analogs have similar activity on bacteria and fungus. This bactericidal and fungicidal behaviour is a novel
area of activity for these entities.
Received 19 July 2010
Received in revised form
2 September 2010
Accepted 3 September 2010
Keywords:
Ferrocene
Iron
Bioorganometallic
Antibacterial
Antifungal
Ó 2010 Elsevier B.V. All rights reserved.
1. Introduction
activity [21]. In addition, ferrocene derivatives can be used as
“electrochemical sensors” for biological substances [22].
Bioorganometallic chemistry, defined as the discipline that
combines study of organometallic molecules with that of their
biological applications, has seen exponential growth in recent years
[1e10]. Of the transition metal complexes studied, ferrocene deriv-
atives are amongst the most interesting. This is particularly due to
the redox potential of ferrocene, as well as its stability and lack of
toxicity. These complexes have numerous applications. For example,
ferrocene analogs of tamoxifen are very active on hormone-
dependent cancer cells, but unlike tamoxifen are also active on
hormone-independent breast cancer cells [11e15]. Modification of
the chloroquine molecule by substitution of a part of the molecule
with a ferrocene groupresultedin a new molecule, ferroquine, active
on malarial strains that are resistant to chloroquine [16e20]. Clinical
trials for this product have now reached phase II. Ferrocene deriv-
atives of quinoxaline have also been studied for their antimalarial
The idea of using a ferrocene group to enhance the activity of
antibiotics was suggested by Edwards et al. in 1976 [23]. These
authors found that incorporation of a ferrocene group into the
penicillin molecule increased its antibiotic activity. In recent years
other articles on the use of transition metals as antibacterials and
antifungals have been published. Chelates formed by complexation
of hydrazone, ceftriaxone or oxalyldihydrazide have been found to
improve antibacterial activity of the relevant species [24,25].
Ferrocene derivatives of ethambutol have been prepared and tested
against Mycobacterium tuberculosis [26,27]; the best compounds
are less active than ethambutol itself. Ferrocenyl derivatives of
dihydropyrazole have also been tested as antibacterials [28,29].
Ferrocenyl derivatives of thiazoloacylhydrazone [30] and of various
peptides[31] have been found to be active on Staphylococcus aureus,
Esherichia coli and Pseudomonas aeruginosa. Ferrocenyl aroylhy-
drazones have shown moderate activity on bacteria and fungi
[32,33]. A ferrocenyl analog of the antifungal fluconaxole has also
been synthesized and its activity is modest compared to that of the
corresponding organic compound [34].
* Corresponding author. Tel.: þ33 1 44 27 66 99; fax: þ33 143260061.
** Corresponding author.
E-mail addresses: siden-top@chimie-paristech.fr (S. Top), ahmed.rebai@cbs.rnrt.
tn (A. Rebai).
In the course of our work on the activity of organometallic
analogs of tamoxifen on breast and prostate cancer, a number of
0022-328X/$ e see front matter Ó 2010 Elsevier B.V. All rights reserved.
doi:10.1016/j.jorganchem.2010.09.015

M. El Arbi et al. / Journal of Organometallic Chemistry 696 (2011) 1038e1048
1039
OH
OH
NH2
NHAc
Fe
Fe
Fe
Fe
O(CH2)3NMe2
OH
3
4
2 Ferrociphenol
1
Hydroxyferrocifen
IC50 = 0.5 µM
µ
µ
µ
M
IC50 = 0.6
M
IC50 = 0.8
M
IC50 = 0.65
Chart 1. Ferrocenyl derivatives and their IC50 values on the hormone independent cancer cells (MDA-MB-231).
complexes have been synthesized. Some compounds demonstrated
excellent cytotoxic activity on both hormone-dependent and
hormone-independent cancer cells. For example, compounds 1
(hydroxyferrocifen) [12], 2 (ferrociphenol) [12], 3 [14] and 4 [14] are
very active on hormone-independent MDA-MB-231 cancer cells,
Citric salts 26 and 27 were prepared by addition of citric acid to 1
and 10, respectively (Scheme 5).
2.2. Biological studies
with IC50 values ranging from 0.5 mM to 0.8 mM (chart 1).
Gram negative strain P. aeruginosa, gram positive strain S. aureus
and fungus C. albicans. were used for inhibitory tests using doxy-
cycline as a positive control. The minimal inhibitory concentrations
The idea of using antibiotics to treat cancers has also been
pointed out. For example, the well-known antibiotic doxycycline
has been found to be active on breast and prostate cancer [35e37].
In addition, tamoxifen has been found to display good antifungal
activity by interfering with calcium homeostasis [38,39]. These
results suggest that there may be a correlation between antitu-
moral activity and antimicrobial activity. Accordingly, we decided
to test the activity of our ferrocene derivatives on pathogenic
bacteria and fungi. For this study we selected two bacterial path-
ogens, P. aeruginosa and S. aureus, and the pathological fungal strain
Candida albicans. Doxycycline, often used in tests to establish anti-
microorganism activity [40e42] was chosen as the standard anti-
biotic for our tests. Chart 2 shows the chemical structure of the 27
products selected for this study.
(MIC, mg/mL) were estimated by the two fold broth dilution tech-
nique in liquid plate count agar (PCA) [54]. Compounds were dis-
solved in ethanol and diluted in the media to concentrations
ranging from 200
fungi/mL were used. After incubation at 30 ꢀC for 24 h, the minimal
inhibitory concentrations (MIC, g/mL and M) were recorded as
mg/mL to 12.5 m
g/mL. Inoculants of 105 bacteria or
m
m
the lowest concentration of compound in the medium that showed
no microbial growth by visual observation. Solvent, media and
positive growth controls were also run simultaneously. The bacte-
ricidal and fungicidal activities were detected after incubation at
30 ꢀC for 24 h of PCA medium sowing from each clear sample.
Minimum inhibitory concentration (MIC), minimum bacteri-
Compounds 1e16, 24, 26 and 27 are ferrocene complexes.
Complexes 26 and 27 are citric salts of 1 and 10 respectively. The
purely organic compounds 17e23 and a ketone, 25, were chosen for
purposes of comparison. Compounds 1 [43], 2 [43], 3 [44], 4 [14], 5
[45], 6 [46],11 [46],12 [47],13 [47],16 [48],17 [49],18 [12],19 [47], 21
[50], 22 [51], 24 [52], have already been reported as part of a study on
their antiproliferative activity on breast cancer cells. Here we focus
on the bactericidal and fungicidal activity of all these compounds.
cidal concentration (MBC,
m
g/mL and
mM) or minimum fungicidal
concentration (MFC, g/mL and
m
mM) values for the compounds are
shown in Table 1. We also show IC50 values for the MDA-MB-231
hormone-independent cancer cells, and lipophilicity, expressed as
log Po/w, for most of the compounds.
The antiproliferative activity on breast cancer cells of most of the
compounds has already been reported. The IC50 values of 7, 8, 9, 11,
16 and 20 are shown in the table and that of 10, 12, 14, 15, 21, 23, 25,
26 and 27 will be determined in the future. Compound 24 is the
only ferrocenophane derivative presented in the table; it is the
2. Results and discussion
most active compound with an IC50 value of 0.09 mM [52]. All tested
2.1. Synthesis
organic compounds 18e20, 22 and 23 are not active while most of
the ferrocene analogs show good activity. For example, the dihy-
droxy 18 is non-toxic while its analog 2 is very active with an IC50
4,40-Bis-dimethylaminopropoxy-benzophenone
25
was
prepared by reacting the dimethylamine with the 4,40-bis-bromo-
propoxy-benzophenone, 28 [53], at 60 ꢀC for 24 h (Scheme 1).
1,1-Bis[4-(3-dimethylaminopropoxy)-phenyl]-2-ferrocenyl-but-1-
ene,10, was prepared from ferrociphenol, 2(Scheme 2). The reaction of
the bromopropane with the sodium phenolate, generated by reacting
the sodium ethanolate with 2, gives first the brominated compound
29. Heating this latter compound with dimethylamine in methanol at
60 ꢀC produced 10 in 57% overall yield.
Amido compounds 7, 8 and 9 were prepared by alkylation of
amino compound 3 by an appropriated acid chloride (Scheme 3). 7,
8 and 9 were obtained in 92%, 76% and 63% yield, respectively.
The reaction of the sodium salt of ferrociphenol 2 with the
pivaloyl chloride gives pivaloate derivatives 14 and 15. Palmitate
compound 23 was prepared in the same way from 18 (Scheme 4).
value of 0.6 mM. The same behaviour was observed for the 22/1 and
20/4 couples. In the case of the amido compounds, the size of the
substituent is important; the antiproliferative activities dramati-
cally decrease from acetamido 4 (IC50 ¼ 0.65
mM) to pivaloylamino
9 (non-toxic). The presence of two palmitate chains in 16 also
inhibits its activity. On the other hand compound 11 with an amino
chain longer than that of ferrocifen 1 is as active as 1. To summarize,
the best compounds are ferrocene derivatives bearing two free
phenols (2 and 24) or one phenol and one amino chain (1 and 11).
The MIC and MBC values for doxycycline were found to be
<12.5
mg/mL and 25
mg/mL respectively on P. aeruginosa, <12.5
mg/
mL and 12.5
mg/mL on S. aureus, and 100
m
g and 200 g/mL on C.
m
albicans.. The compounds tested can be grouped into three cate-
gories. The first one contains the compounds possessing an activity

1040
M. El Arbi et al. / Journal of Organometallic Chemistry 696 (2011) 1038e1048
Ferrocenyl derivatives
R1 = OH; R2 = O(CH2)3NMe2
1
2 R1 = R2 = OH
3 R1 = H; R2 = NH2
R1 = H; R2 = NHAc
R2
4
5
6
7
R1 = R2 = H
HO
R1 = H; R2 = OH
R1 = H; R2 = NHCOEt
8 R1 = H; R2 = NHCOiPr
9 R1 = H; R2 = NHCOtBu
R1 = R2 = O(CH2)3NMe2
OH
Fe
10
Fe
R1
R1 = OH; R2 = O(CH2)4NMe2
11
12 R1 = H; R2 = Br
24
R1 = H; R2 = CN
13
14
15
16
R1 = OH; R2 = OCOtBu
R1 = R2 = OCOtBu
R1 = R2 = OCO(CH2)14CH3
O(CH2)3NMe2
Organic derivatives
R2
R1 = H; R2 = OH
17
18
O
R1 = R2 = OH
19 R1 = H; R2 = NH2
R1 = H; R2 = NHAc
20
21
R1 = R2 = O(CH2)3NMe2
O(CH2)3NMe2
R1 = OH; R2 = O(CH2)3NMe2
22
R1
OH
25
23 R1 = R2 = OCO(CH2)14CH3
O(CH2)3NMe2H
COOH
OH
COOH
COOH
OOC
OOC
HO
OOC
Fe
Fe
O(CH2)3NMe2H
O(CH2)3NMe2H
26
27
Chart 2. Compounds selected for this study.
similar or superior to that of doxycycline. These are the purely
organic compounds 21 and 22, which bear one or two amino chains
on the molecule. They are in fact more active than doxycycline on C.
albicans.. The second category is that of compounds slightly less
active than doxycycline. In this category are found the ferrocene
derivatives 1, 10 and 11, which are ferrocenyl analogs of compounds
21 and 22. The final category includes all the remaining products,
with MIC and MBC values around 100 mM and 200 mM, respectively.
The first observation to be made from this result is that the pres-
ence of the dimethylamino alkyl chain is instrumental for the
activity of the compound. This is certainly the case for compounds
21, 22, 1, 10 and 11. OH, NH2, NHCOR, Br or CN substituents in para
position play essentially no role, since the products bearing these
functions have the same activity as the unsubstituted compound 5.
Examination of the antimicrobial activity of the organic compound/
ferrocene analog pairs 17/6, 18/2, 19/3, 20/4, 22/1 and 21/10 clearly
show that the aromatic ferrocenyl group behaves like a phenyl,
indeed it produces a slight deactivation in certain cases since it is
more bulky than a flat arene. This behaviour is opposite to the one
we observed for breast cancer cells where the redox effect of
ferrocene is triggered. In fact the organic compounds 18, 19, 20 and
O(CH2)3Br
O(CH2)3NMe2
HNMe2, MeOH
O
O
60°C, 24 hrs
O(CH2)3Br
O(CH2)3NMe2
28
25
88%
Scheme 1. Synthesis of 4,40-bis-dimethylaminopropoxy-benzophenone 25.

M. El Arbi et al. / Journal of Organometallic Chemistry 696 (2011) 1038e1048
1041
OH
O(CH2)3Br
1) EtONa, EtOH
2)
Br
3
Br
Fe
Fe
OH
O(CH2)3Br
29
HNMe2 60°C
2
24 hrs
MeOH
O(CH2)3NMe2
Fe
O(CH2)3NMe2
10 57% overall yield
Scheme 2. Synthesis of ferrocenyl diamino compound 10.
NH2
NHCOR
RCOCl
7 R = Et 92%
8 R = iPr 76%
9 R = tBu 63%
Pyridine
Fe
Fe
3
Scheme 3. Synthesis of amido compounds 7, 8 and 9.
22 are inactive on hormone-independent MDA-MB-231 breast
cancer cells, while their ferrocenyl analogs 2, 3, 4 and 1 are amongst
but less active on microorganisms. The only shared characteristic
between P. aeruginosa, S. aureus, C. albicans. and MDA-MB-231
cancer cells seems to be their sensitivity towards compounds
bearing amino alkyl chains. The monoamine compounds 22 and 1
are active on the three microorganisms, with MIC values ranging
the most effective, with IC50 values between 0.5
m
M and 0.8
m
M.
This difference is confirmed with compound 24, which is very
active on MDA-MB-231 cancer cells, with an IC50 value of 0.09
m
M,
R'
O
R'
O
OH
O
O
NaH , THF
R
R'COCl
R
R
R'
OH
OH
O
O
15 R = Fc; R' = t-Bu 28%
23 R = Ph; R' = -(CH2)14CH3 96%
2 R = Fc
18 R = Ph
14 R = Fc; R' = t-Bu 34%
Scheme 4. Synthesis of pivaloate derivatives 14 and 15 and palmitate derivative 23.

1042
M. El Arbi et al. / Journal of Organometallic Chemistry 696 (2011) 1038e1048
OH
O(CH2)3NMe2
Fe
Fe
O(CH2)3NMe2
O(CH2)3NMe2
COOH
10
1
COOH
HO
HO
HOOC
THF/diethyl ether
THF/diethyl ether
COOH
COOH
HOOC
OH
O(CH2)3NMe2H
COOH
OH
OOC
OOC
COOH
COOH
HO
OOC
Fe
Fe
O(CH2)3NMe2H
O(CH2)3NMe2H
84%
27
26
85%
Scheme 5. Synthesis of citric salts 26 and 27.
Table 1
Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) or minimum fungicidal concentration (MFC), IC50 and log Po/w values.
Cpd. Num.
Pseudomonas
aeruginosa
Staphylococcus
aureus ( g/mL (
Candida albicans
g/mL ( M))
IC50 on MDA-MB-231 (
m
M)
log Po/w
R2
m
m
M))
(
m
m
(mg/mL (mM))
R3
R1
MIC
MBC
<12.5 (<28.1)
25 (56.2)
<12.5 (<28.1)
12.5 (28.1)
100 (225)
OH
O
OH
O
O
200a (450)
OH
H
NH2
OH
H
e
e
CH3 OH
H3C
N
CH3
Doxycycline
MIC
MBC
25 (65.0)
50 (130.0)
50 (130.0)
200 (520.1)
50 (130.0)
O(CH2)3NMe2
O(CH2)3NMe2
100a (260.0)
O
25
e
e
5
R1 ¼ R2 ¼ H
R3 ¼ Fc
MIC
MBC
MIC
MBC
MIC
MBC
MIC
MBC
100 (254.9)
200 (509.8)
25 (83.2)
100 (332.9)
100 (244.9)
200 (489.8)
100 (316.1)
200 (632.1)
100 (254.9)
200(509.8)
25 (83.2)
100 (332.9)
100 (244.9)
200 (489.8)
100 (316.1)
200 (632.1)
100 (254.9)
200a (509.8)
100 (332.9)
200a(665.8)
100 (244.9)
200a (489.8)
100 (316.1)
200a (632.1)
7.54
e
6.43
e
17
6
R1 ¼ H; R2 ¼ OH
R3 ¼ Ph
R1 ¼ H; R2 ¼ OH
R3 ¼ Fc
1.13b
n.toxc
6.17b
4.4c
18
R1 ¼ OH; R2 ¼ OH
R3 ¼ Ph

M. El Arbi et al. / Journal of Organometallic Chemistry 696 (2011) 1038e1048
1043
Table 1 (continued)
Cpd. Num.
Pseudomonas
aeruginosa
Staphylococcus
aureus ( g/mL (
Candida albicans
g/mL ( M))
IC50 on MDA-MB-231 (
mM)
log Po/w
R2
m
m
M))
(
m
m
(mg/mL (mM))
R3
R1
2
R1 ¼ OH; R2 ¼ OH
R3 ¼ Fc
MIC
MBC
MIC
MBC
MIC
MBC
MIC
MBC
MIC
MBC
MIC
MBC
MIC
MBC
100 (235.67)
200 (471.35)
50 (167)
200 (678)
25 (61.4)
50 (122.7)
100 (292.9)
200 (585.7)
100 (222.5)
200 (445.1)
100 (215.80)
200 (431.6)
100 (209.5)
200 (418.9)
100 (235.67)
200 (471.35)
50 (167)
200 (678)
100 (245.5)
200 (491)
100 (292.9)
200 (585.7)
100 (222.5)
200 (445.1)
100 (215.80)
200 (431.6)
100 (209.5)
200 (418.9)
100 (235.67)
200a (471.35)
50 (167)
0.6c
5.0c
19
3
R1 ¼ H; R2 ¼ NH2
R3 ¼ Ph
> 1
0.8d
55.4
m
Md
4.86d
5.75d
e
200a (678)
R1 ¼ H; R2 ¼ NH2
R3 ¼ Fc
100 (245.5)
200a (491)
20
4
R1 ¼ H; R2 ¼ NHAc
R3 ¼ Ph
100 (292.9)
200a (585.7)
100 (222.5)
200a (445.1)
100 (215.80)
200a (431.6)
100 (209.5)
200a (418.9)
R1 ¼ H; R2 ¼ NHAc
R3 ¼ Fc
0.65d
1.2
5.92d
5.89
6.13
7
R1 ¼ H; R2 ¼ NHCOEt
R3 ¼ Fc
8
R1 ¼ H;
2.02
R2 ¼ NHCOiPr
R3 ¼ Fc
9
R1 ¼ H; R2 ¼ NHCOtBu
R3 ¼ Fc
MIC
MBC
MIC
MBC
100 (203.5)
200 (407)
<12.5 (<31.1)
<12.5 (<31.1)
100 (203.5)
200 (407)
12.5 (31.1)
25 (62.3)
100 (203.5)
200a (407)
25 (62.3)
> 1
mM
6.35
5.75
22
R1 ¼ OH
n.tox
0.5c
nd
R2 ¼ O(CH2)3NMe2
R3 ¼ Ph
50a (124.5)
1
R1 ¼ OH
MIC
MBC
25 (49.1)
50 (98.1)
25 (49.1)
50 (98.1)
50 (98.1)
4.40c
nd
R2 ¼ O(CH2)3NMe2
R3 ¼ Fc
100a (196.3)
21
10
R1 ¼ O(CH2)3NMe2
R2 ¼ O(CH2)3NMe2;
R3 ¼ Ph
MIC
MBC
<12.5 (<25.7)
<12.5 (<25.7)
<12.5 (<25.7)
25 (51.4)
<12.5 (<25.7)
<12.5a (<25.7)
R1 ¼ O(CH2)3NMe2
R2 ¼ O(CH2)3NMe2
R3 ¼ Fc
MIC
MBC
<12.5 (<21.02)
50 (84.1)
<12.5 (<21.02)
25 (42.0)
<12.5 (<21.02)
nd
nd
50a (84.1)
11
12
13
14
R1 ¼ OH
MIC
MBC
MIC
MBC
MIC
MBC
MIC
MBC
50 (95.5)
50 (95.5)
25 (47.7)
y 0.5
4.06
nd
R2 ¼ O(CH2)4NMe2; R3 ¼ Fc
R1 ¼ H; R2 ¼ Br
R3 ¼ Fc
100 (191.0)
100 (212.2)
200 (424.4)
50 (119.8)
200 (479.2)
50 (98.3)
100 (191.0)
100 (212.2)
200 (424.4)
100 (239.6)
200 (479.2)
100 (196.7)
200 (393.4)
100a (191.0)
100 (212.2)
200a (424.4)
100 (239.6)
200a (479.2)
100 (196.7)
200a (393.4)
[1
11e
nd
m
Me
R1 ¼ H; R2 ¼ CN
R3 ¼ Fc (Z isomer)
R1 ¼ OH;
6.37e
nd
R2 ¼ OCOtBu
R3 ¼ Fc
200 (393.4)
15
16
23
R1 ¼ OCOtBu
R2 ¼ OCOtBu;
R3 ¼ Fc
MIC
MBC
100 (168.7)
200 (337.5)
100 (168.7)
200 (337.5)
50 (168.7)
nd
nd
nd
nd
200a (337.5)
R1 ¼ OCOC15H31
R2 ¼ OCOC15H31
R3 ¼ Fc
MIC
MBC
50 (55.5)
200 (221.9)
100 (111.0)
200 (221.9)
100 (111.0)
n.tox
nd
200a (221.94)
R1 ¼ OCOC15H31
R2 ¼ OCOC15H31
R3 ¼ Ph
MIC
MBC
50 (63.0)
200 (252.1)
50 (63.0)
200 (252.1)
100 (126.0)
200a (252.1)
26
27
R1 ¼ O(CH2)3NMe2Hþ
R2 ¼ OH; R3 ¼ Fc
R1 ¼ O(CH2)3NMe2Hþ
R2 ¼ O(CH2)3NMe2Hþ
R3 ¼ Fc
MIC
MBC
MIC
MBC
25 (35.6)
50 (71.3)
25 (31.1)
200 (248.5)
50 (71.3)
100 (142.5)
25 (31.1)
25 (35.6)
nd
nd
nd
nd
100a (142.5)
<12.5 (<15.5)
>200a (>248.5)
200 (248.5)
MIC
MBC
100 (236.8)
200 (473.6)
100 (236.8)
200 (473.6)
100 (236.8)
200a (473.6)
HO
24
0.09f
4.60
OH
Fe
a
MFC value; n.tox: non-toxic at 10 mM; nd: not determined.
b
c
d
e
f
Values from Ref. [45].
Values from Ref. [12].
Values from Ref. [14].
Values from Ref. [47].
Values from Ref. [52].

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M. El Arbi et al. / Journal of Organometallic Chemistry 696 (2011) 1038e1048
120
100
80
60
40
20
0
7
6,5
6
5,5
5
4,5
4
3,5
3
MIC-Pseudomonas aeruginosa
Log Po / w
11
18
1
24
19
2
22
3
7
4
6
8
9
13
5
compound number
Fig. 1. Log Po/w and MIC values (mg/mL) of selected compounds.
from <12.5 to 50
m
g/mL. The compound with a longer alkylamino
compounds bearing alkylamino chains are very active, and in these
cases the antimicrobial activity increases for compounds bearing two
amino chains. They are equally as active as doxycycline on P. aerugi-
nosa and S. aureus but superior to it on C. albicans.. Consequently we
intendtoconcentrateourfuturestudiesonthistypeofcompoundand
will attempt to elucidate the reasons for this interesting activity
whichopensupnew directions inresearchintoactiveantibiotics. This
is an important goal of current anti-infective research [38].
chain is slightly less active. Antimicrobial activity becomes very
pronounced when the molecules have two amino chains. This is the
case for the organic diamino compound 21 and the ferrocenyl
diamino compound 10, with MIC values of <12.5
values of <12.5e50 g/mL. They are thus as active as doxycycline
but become superior to the latter on the fungus C. albicans.. Even
the diamino ketone 25 is slightly active. Interestingly, tamoxifen,
which also contains alkyamino chain, exhibits antifungal activity
mg/mL and MBC
m
with MIC values ranging from 8 to 64 mg/mL [38,39]. It may be
4. Experimental
noted that, compounds 1 and 11, which are slightly active, are ones
of the most hydrophilic compounds in the list (log Po/w ¼ 4.40 and
4.06, respectively). However, it seems that the hydrophilicity of
compounds does not play an important role because both the low
lipophilic compound 18 (log Po/w ¼ 4.4) and the most lipophilic
compound 5 (log Po/w ¼ 6.43) have the same antimicrobial activity.
Fig.1 shows clearly the lack of correlation between lipophilicity and
microbial activity on P. aeruginosa.
4.1. Synthesis and characterization of compounds
The synthesis of all compounds was performed under an argon
atmosphere, using standard Schlenk techniques. Anhydrous THF
was obtained by distillation from sodium/benzophenone. Thin
layer chromatography was performed on silica gel 60 GF254.
Infrared spectra were obtained on IR-FT BOMEM Michelson-100
and FT/IR-4100 JASCO spectrometers. 1H and 13C NMR spectra were
recorded on a 300 MHz Bruker spectrometer. Mass spectrometry
was performed with a Nermag R 10-10C spectrometer. Elemental
analyses were performed by the microanalysis service of CNRS at
Gif sur Yvette. The preparative HPLC separations were performed
on a Shimadzu apparatus with a Nucleodur C18 column (length of
It may be noted that cobaltifen, a cobalt complex analog of
hydroxytamoxifen, which bears two amino chains, is active on
MDA-MB-231 cancer cells (IC50 ¼ 2.5 ꢁ 0.4
mM) [50]. It also seems
to show that the amino chain, presented in the molecules, is
responsible for their antimicrobial activity. We have previously
suggested that ferrocifen 1 might target calmodulin [11]. Dolan
et al. have recently investigated the antifungal activity of tamox-
ifen, they conclude that the ability of tamoxifen to interfere with
calmodulin is part of its mechanism of action [38]. As the basic
chain could complex Caþþ, the involvement of calmodulin in the
antimicrobial activity of our amino compounds should be envis-
aged as one of the possible mechanisms. The transformation of
compounds 1 and 10 into citric salts 26 and 27 decreases their
activity slightly but improves their solubility in water. The amides 4,
20, 7, 8 and 9 and the esters 23, 14, 15, 16 are amongst the least
active compounds, all with similar MIC and MBC values.
25 cm, diameter of 2.5 cm, and particle size of 10 mm).
4.2. 4,40-Bis-dimethylaminopropoxy-benzophenone, 25
4,40-Bis-bromopropoxy-benzophenone 28 [53] (0.365 g,
0.8 mmol) was added to a solution of dimethylamine in methanol
(2 M, 4.8 mL, 9.6 mmol) placed in a pressure tube. The mixture was
heated with stirring at 60 ꢀC for 24 h. After cooling, the mixture was
concentrated under reduced pressure, dissolved in dichloro-
methane, washed with an aqueous solution of sodium hydro-
genocarbonate, then with water. The organic phase was dried
(MgSO4), filtered and concentrated. The crude product was recrys-
tallized from an ether/petroleum ether solution to yield 25 in 88%
3. Conclusion
Twenty seven ferrocenyl or phenyl derivatives in the diphenyl
butene series were tested on the bacteria P. aeruginosa and S. aureus
and on the fungus C. albicans.. The results obtained appear to show
thatthere are nogeneral correlation betweenthe cytotoxic activityon
cancer cells and the bactericidal or fungicidal activity of the
compounds. Theferrocenederivativesandtheirorganicanalogsshow
similar levels of activity on the bacteria and the fungus. Only the
yield. mp: 75 ꢀC. 1H NMR (CDCl3) :
d 1.80e2.00 (m, 4H, CH2), 2.19 (s,
12H, NMe2), 2.39 (t, J ¼ 7.1 Hz, 4H, CH2N), 4.02 (t, J ¼ 6.4 Hz, 4H,
CH2O), 6.88 (d, J ¼ 8.8 Hz, 4H, C6H4), 7.69 (d, J ¼ 8.8 Hz, 4H, C6H4). 13
C
NMR (CDCl3):
d 26.4 (2 CH2), 44.5 (2 NMe2), 55.2 (2 CH2N), 65.4 (2
CH2O),112.9 (2 ꢂ 2 CH C6H4),129.6 (2C, C6H4),131.2 (2 ꢂ 2 CH, C6H4),
161.3 (2C, C6H4),193.5 (CO). IR (KBr, n
cmꢃ1): 3035, 2951, 2866, 2812,
2762 (CH2, CH3). MS (CI, NH3) m/z : 385 [M þ H]þ. Anal. Calcd. for

M. El Arbi et al. / Journal of Organometallic Chemistry 696 (2011) 1038e1048
1045
C23H32N2O3: C, 71.84; H, 8.38; N, 7.28. Found: C, 71.81; H, 8.41; N,
7.29.
J ¼ 7.3 Hz, 3H, CH3),1.12 and 1.14 (t, J ¼ 7.3 Hz, 3H, CH3), 2.25 and 2.28
(q, J ¼ 7.3 Hz, 2H, CH2), 2.45 and 2.47 (q, J ¼ 7.3 Hz, 2H, CH2), 3.79 and
3.85 (s, 2H, H C5H4), 3.98 and 4.00 (s, 2H, H C5H4), 4.02 and 4.03 (s, 5H,
Cp), 6.91 and 6.95 (d, J ¼ 8.0 Hz, 2H, Harom), 7.00e7.43 (m, 7H, Harom).
4.3. 1,1-Bis[4-(3-dimethylaminopropoxy)phenyl]-2-ferrocenyl-but-
1-ene, 10
13C NMR (CDCl3):
d 7.8 (CH3), 13.5 (CH3), 25.9 and 26.1 (CH2), 28.9
(CH2), 66.5 and 66.7 (2 CH C5H4), 67.5 and 67.6 (2CH C5H4), 67.7 and
67.8 (5 CH Cp), 85.2 and 85.5 (Cipso), 117.5 and 117.7 (2 CHarom), 124.3
(CHarom), 126.2 and 126.3 (2 CHarom),127.5 and 128.0 (2 CHarom),128.1
and 128.7 (2 CHarom),134.2 (C),135.5 (C),135.6 (C),138.5and 138.6(C),
1,1-Bis(4-hydroxyphenyl)-2-ferrocenyl-but-1-ene
2 (3.00 g,
7.7 mmol) was added to a solution of sodium ethanolate prepared by
addition of sodium (0.325 g,14.1 mmol) to ethanol (20 mL). After the
mixture had been stirred at reflux for 1 h, dibromopropane (8.560 g,
42.4 mmol) was added. After 1 h at reflux, the solution was left to
cool to room temperature and was hydrolysed with water (100 mL).
The product was extracted with dichloromethane. The organic
phase was washed with water, dried over magnesium sulfate,
filtered, and the mixture was concentrated under reduced pressure.
The crude mixture of products was chromatographed on a silica gel
column with petroleum ether as an eluent. The first colored band
mainly contained the dibromo product 29. The crude product was
used without further purification in the second step: The compound
was transferred into a pressure tube and a 2 M solution of dime-
thylamine in methanol (30 mL, 60 mmol) was added. The pressure
tube was heated at 60 ꢀC for 24 h and then was cooled to room
temperature. The solution was concentrated under reduced pres-
sure, dissolved in dichloromethane, washed with a solution of
saturated sodium hydrogenocarbonate and water, dried on
magnesium sulfate and concentrated under reduced pressure. The
crude mixture was chromatographed on silica gel column. Acetone
was first used as an eluent to remove the by-products, it was fol-
lowed by a solution of triethylamine at 10% in acetone to elute the
pure compound 10. It was obtained as an oil with a yield of 57%. 1H
142.4and142.7(C),169.9and170.0(CON).IR(KBr, n
cmꢃ1):3451, 3272
(NH), 3094, 2967, 2930, 2872 (CH2, CH3),1650 (CON). MS (EI, 70eV) m/
z : 463 [M]þ., 398, 397, 326, 121 [CpFe]þ. HRMS (ESI, C29H29FeNO:
[M]þ.
) calcd.: 463.15931, found: 463.15884. Anal. Calcd. for
C29H29FeNO: C, 75.16; H, 6.3; N, 3.02. Found: C, 74.78; H, 6.41; N, 2.73.
4.6. 1-(4-Isobutyrylaminophenyl)-1-phenyl-2-ferrocenyl-but-1-
ene, 8
2-Ferrocenyl-1-(4-aminophenyl)-1-phenyl-but-1-ene 3 (410 mg,
1 mmol); anhydrous THF (15 mL); isobutyryl chloride (117 mg,
1.1 mmol); pyridine (87 mg,1.1 mmol). Compound 8 was obtained as
ayellowsolid (362 mg, 76%yield) consistingof undeterminated 55/45
mixture of Z and E isomers. 1H NMR (CDCl3):
d 0.91 and 0.92 (t,
J ¼ 7.3 Hz, 3H, CH3), 1.13 and 1.15 (d, J ¼ 6.2 Hz, 6H, 2 CH3), 2.30e2.53
(m, 3H, CH2 þ CH), 3.80 and 3.88 (s, 2H, C5H4), 3.99 and 4.00 (s, 2H,
C5H4), 4.03 and 4.04 (s, 5H, Cp), 6.92 and 6.96 (d, J ¼ 8.1 Hz, 2H, Harom),
6.99e7.44 (m, 7H, Harom). 13C NMR (CDCl3):
d 15.4 and 15.5 (CH3),19.7
(2 CH3), 27.9 and 28.0(CH2), 36.8(CH), 68.6 and 68.9 (2 CH, C5H4), 69.5
and 69.7 (2 CH, C5H4), 69.7 and 69.9 (5 CH, Cp), 86.0 (Cipso), 119.4 and
119.6 (2 CHarom),126.2 (CHarom), 128.1 and 128.2 (2 CHarom),129.5 and
129.9 (2 CHarom), 130.0 and 130.7 (2 CHarom),136.2 (C),137.4 and 137.6
(C), 137.6 and 137.7 (C), 140.4 and 140.5 (C), 144.3 and 144.6 (C),175.0
NMR (CDCl3) :
d
0.94 (t, J ¼ 7.4 Hz, 3H, CH3),1.79e1.95 (m, 4H, 2 CH2),
2.18 (s, 6H, NMe2), 2.19 (s, 6H, NMe2), 2.37 (t, J ¼ 7.2 Hz, 2H, CH2N),
2.40 (t, J ¼ 7.2 Hz, 2H, CH2N), 2.50 (q, J ¼ 7.4 Hz, 2H, CH2), 3.83 (t,
J ¼ 1.9 Hz, 2H, C5H4), 3.89 (t, J ¼ 6.6 Hz, 2H, CH2O), 3.91 (t, J ¼ 6.6 Hz,
2H, CH2O), 3.98 (t, J ¼ 1.9 Hz, 2H, C5H4), 4.02 (s, 5H, Cp), 6.66 (d,
J ¼ 8.7 Hz, 2H, C6H4), 6.77 (d, J ¼ 8.7 Hz, 2H, C6H4), 6.86 (d, J ¼ 8.7 Hz,
and 175.1 (CON). IR (KBr, n
cmꢃ1): 3451, 3262 (NH), 3094, 2967, 2930,
2871 (CH, CH2, CH3), 1652 (CON). MS (EI, 70 eV) m/z: 477 [M]þ, 412,
342, 326, 121 [CpFe]þ. HRMS (ESI, C30H31FeNO: [M]þ) calcd.:
477.17496, found: 477.17429.
2H, C6H4), 7.02 (d, J ¼ 8.7 Hz, 2H, C6H4).13C NMR (CDCl3):
d 15.5 (CH3),
27.5 (CH2), 27.6 (CH2), 27.9 (CH2), 45.5 (2 NMe2), 56.5 (2 CH2N), 66.1
(2 CH2O), 67.9 (2 CH C5H4), 69.1 (5 CH, Cp), 69.3 (2 CH, C5H4), 87.2
(Cipso),114.1 (2 CH, C6H4),114.2 (2 CH, C6H4),130.4 (2 CH, C6H4),130.9
(2 CH, C6H4),136.5(C),137.2(C),137.3(C),137.4 (C),157.3(2C). IR (KBr,
4.7. 1-(4-Pivaloylaminophenyl)-1-phenyl-2-ferrocenyl-but-1-ene, 9
2-Ferrocenyl-1-(4-aminophenyl)-1-phenyl-but-1-ene 3 (410 mg,
1 mmol); anhydrous THF (15 mL); Trimethyl acetyl chloride (132 mg,
1.1 mmol); pyridine (87 mg,1.1 mmol). Compound 9 was obtained as
a yellow solid (309 mg, 63% yield) consisting of undeterminated 60/
n
cmꢃ1): 3093, 3032, 2947, 2866, 2816, 2765 (CH2, CH3). MS (EI,
70 eV) m/z: 594 [M]þ., 121 [CpFe]þ, 86 [CH2CH2CH2NMe2]þ, 58
[CH2NMe2]þ. HRMS (ESI, C36H47FeN2O2: [M
595.29815, found: 595.29681.
þ
H]þ) calcd.:
40 mixture of Z and E isomers. 1H NMR (CDCl3):
d
0.91 and 0.92 (t,
t
J ¼ 7.3 Hz, 3H, CH3), 1.20 and 1.22 (s, 9H, Bu), 2.45 and 2.47 (q,
J ¼ 7.3 Hz, 2H, CH2), 3.79 and 3.86 (s, 2H, C5H4), 3.98 and 4.00 (s, 2H,
C5H4), 4.02 and 4.03 (s, 5H, Cp), 6.87e7.44 (m, 9H, Harom). 13C NMR
4.4. General procedure for the synthesis of amido compounds 7, 8
and 9
(CDCl3):
d
15.4 (CH3), 27.7 (3 CH3, tBu), 28.0 (CH2), 39.6 (C tBu), 68.8
and 69.1 (2 CH, C5H4), 69.6 and 69.8 (2 CH, C5H4), 69.9 and 70.1 (5 CH,
Cp), 87.9 (Cipso), 119.6 and 119.8 (2 CHarom), 126.2 (CHarom), 128.1 and
128.2 (2 CHarom), 129.5 and 130.0 (2 CHarom), 130.0 and 130.7
(2 CHarom), 136.2 (C), 137.4 and 137.5 (C), 137.6 and 137.7 (C), 140.4
In
a Schlenk flask under argon, 2-ferrocenyl-1-(4-amino-
phenyl)-1-phenyl-but-1-ene 3 [44] was dissolved in anhydrous
THF. Acid chloride and pyridine were added and the reaction
mixture was stirred for 3 h. Water was added and the product was
extracted with dichloromethane. The organic phase was washed
with water, dried over magnesium sulfate, filtered, and the solvent
was evaporated. The product was purified on a silica gel column
with ether/pentane (1/1) as an eluent.
and 140.6 I, 144.2 and 144.5 (C), 176.4 and 176.5 (CON). IR (KBr,
n
cmꢃ1): 3432 (NH), 3094, 2965, 2929, 2871 (CH2, CH3), 1655 (CON).
MS (EI, 70 eV) m/z: 491 [M]þ., 426, 377, 343, 326, 121 [CpFe]þ. HRMS
(ESI, C31H33FeNO: [M]þ) calcd.: 491.19061, found: 491.18981. Anal.
Calcd. for C31H33FeNO: C, 75.76; H, 6.76; N, 2.85. Found: C, 75.59; H,
6.83; N, 2.82.
4.5. 1-(4-Propionylaminophenyl)-1-phenyl-2-ferrocenyl-but-1-ene, 7
4.8. 1-(4-Hydroxyphenyl)-1-(4-pivaloyloxyphenyl)-2-ferrocenyl-
but-1-ene 14 and 1,1-Bis(4-pivaloyloxyphenyl)-2-ferrocenyl-but-1-
ene, 15
2-Ferrocenyl-1-(4-aminophenyl)-1-phenyl-but-1-ene 3 (810 mg,
2 mmol); anhydrous THF (30 mL); propionyl chloride (204 mg,
2.2mmol);pyridine(174mg,2.2mmol).Compound7was obtained as
ayellowsolid(890mg, 92% yield)consistingofundeterminated55/45
In a Schlenk tube, ferrociphenol 2 (1.272 g, 3 mmol) was dis-
solved in anhydrous THF, then sodium hydride (0.16 g, 4 mmol, 60%
mixture of Z and E isomers. 1H NMR (CDCl3):
d
0.91 and 0.92 (t,

1046
M. El Arbi et al. / Journal of Organometallic Chemistry 696 (2011) 1038e1048
suspension in oil) was added. After 10 min under stirring, trime-
thylacetyl chloride (0.362 g, 0.37 mL, 3 mmol) was added and the
mixture was stirred for 3 h. The mixture was poured into water,
extracted twice with dichloromethane and concentrated under
reduced pressure. Then the residue was chromatographed on
a silica gel column. The compounds were first eluted by dichloro-
methane/petroleum ether 1/1, and after by dichloromethane. 1-(4-
Hydroxyphenyl)-1-(4-pivaloyloxyphenyl)-2-ferrocenyl-but-1-ene
14 (undeterminated 55/45 mixture of Z and E isomers) and 1,1-bis-
(4-pivaloyloxyphenyl)-2-ferrocenyl-but-1-ene 15 were obtained in
34% and 28% yields, respectively, after recrystallization from diethyl
4.10. 1-[4-(3-Dimethylamoniumpropoxy)phenyl]-1-(4-
hydroxyphenyl)-2-ferrocenyl-but-1-ene citrate, 26
1 (0.509 g, 1 mmol) was dissolved into 10 mL of THF. 40 mL of
diethyl ether was added. A solution of citric acid (0.189 g, 0.9 mmol),
in THF (5 mL) was added dropwise into the first solution. A yellow
precipitate was immediately formed. After stirring for 20 min, the
solutionwas stripped off bysyringeand the yellow solid was washed
with 10 mL of diethyl ether and dried under vacuum. 0.550 g of 26
were obtained (85% yield). 1H NMR (CD3OD) (Z/E y 50/50):
d 0.98 (t,
J ¼ 7.3 Hz, 3H, CH3 for one isomer),1.00 (t, J ¼ 7.3 Hz, 3H, CH3 for one
isomer), 2.21 (broad m, 2H, CH2), 2.60 (q, J ¼ 7.3 Hz, 2H, CH2 for one
isomer), 2.74 (d, J ¼ 15.3 Hz, 2H, CH2), 2.79 (d, J ¼ 15.3 Hz, 2H, CH2),
2.85 and 2.86 (2s, 6H, NMe2Hþ), 3.24 (broad m, 2H, CH2N), 3.87 (t,
J ¼ 1.9 Hz, 2H, C5H4 for one isomer), 3.89 (t, J ¼ 1.9 Hz, 2H, C5H4 for
one isomer), 4.04 (m, 4H, CH2O þ C5H4), 4.09 (s, 5H, Cp), 6.61 (d, 2H,
Harom for one isomer), 6.73 (d, 2H, Harom for one isomer), 6.76 (d, 2H,
Harom for one isomer), 6.79 (d, 2H, Harom for one isomer), 6.90 (d, 4H,
Harom), 6.98 (d, 2H, Harom for one isomer), 7.10 (d, 2H, Harom for one
ether/pentane. 14: 1H NMR (CDCl3):
d
0.93 and 0.94 (t, J ¼ 7.4 Hz,
3H, CH3), 1.26 and 1.28 (s, 9H, tBu), 2.48 and 2.52 (q, J ¼ 7.4 Hz, 2H,
CH2), 3.83 and 3.84 (t, J ¼ 1.9 Hz, 2H, C5H4), 3.98 and 3.99 (t,
J ¼ 1.9 Hz, 2H, C5H4), 4.01 and 4.02 (s, 5H, Cp), 5.80 and 5.90 (s, 1H,
OH), 6.57 and 6.68 (d, J ¼ 8.5 Hz, 2H, C6H4), 6.81 (d, J ¼ 8.5 Hz, 2H,
C6H4), 6.94 and 7.12 (d, J ¼ 8.5 Hz, 2H, C6H4), 6.96 (d, J ¼ 8.5 Hz, 2H,
C6H4). 13C NMR (CDCl3): 15.4 and 15.5 (CH3), 27.2 (3 CH3, tBu), 27.9
d
t
and 28.1 (CH2), 39.1 (C Bu), 68.0 and 68.1 (2 CH, C5H4), 68.1 and
68.2 (2 CH, C5H4), 69.2 and 69.3 (5 CH, Cp), 86.8 and 86.9 (Cipso),
115.1 and 115.2 (2 CH, C6H4), 121.0 and 121.2 (2 CH, C6H4), 130.3 and
130.7 (2 CH, C6H4), 130.9 and 131.2 (2 CH, C6H4), 136.5 and 136.7 (C),
137.3 and 137.6 (C), 142.2 and 142.4 (C), 149.2 and 149.3 (C), 154.4
isomer). 13C NMR (CD3OD):
d 15.9 (CH3), 25.7 (CH2), 29.1 (CH2), 43.6
(NMe2Hþ), 45.3 (CH2), 56.7 (CH2N), 66.1 (CH2O), 68.9 (2 CH, C5H4),
70.1 (5 CH, Cp), 70.3 (2 CH, C5H4), 74.6 (Cq, citrate), 88.7 (Cipso C5H4),
115.1 (2 CH, C6H4 for one isomer), 115.3 (2 CH, C6H4 for one isomer),
115.9 (2 CH for one isomer), 116.0 (2 CH, 115.1 2 CH for one isomer),
131.6 (2 CH, C6H4), 132.2 (2 CH, C6H4), 137.7 I, 137.8 I, 138.8 I, 139.2 I,
(2C),177.4 (CO). IR (KBr, n
cmꢃ1): 3437 (OH), 3093, 3035, 2970, 2927,
2873 (CH2, CH3), 1732 (CO). MS (EI, 70 eV) m/z: 508 [M]þ, 443, 359,
121 [CpFe]þ, 57 [tBu]þ. Anal. Calcd. for C31H32FeO3 (H2O)0.2: C,
72.72; H, 6.38. Found: C, 72.68; H, 6.33. 1,1-bis-(4-pivaloylox-
yphenyl)-2-ferrocenyl-but-1-ene, 15: mp: 191 ꢀC 1H NMR (CDCl3):
156.9 I,158.3 I,175.9 (2 ꢂ CO),180.3 (CO). IR (KBr,
n
cmꢃ1): 3421 (OH),
3093, 3032, 2966, 2873 (CH2, CH3), 1720 (CO). 26 contains traces of
solvents (THF and diethyl ether).
d
0.94 (t, J ¼ 7.2 Hz, 3H, CH3), 1.26 (s, 9H, tBu), 1.29 (s, 9H, tBu), 2.47
(q, J ¼ 7.2 Hz, 2H, CH2), 3.90 (s, 2H, C5H4), 4.07 (s, 7H, C5H4 þ Cp),
6.83 (d, J ¼ 8.5 Hz, 2H, C6H4 ), 6.95 (d, J ¼ 8.5 Hz, 2H, C6H4), 6.97 (d,
4.11. 1,1-Bis-[4-(3-Dimethylamoniumpropoxy)phenyl]-phenyl]-2-
ferrocenyl-but-1-ene citrate 27
J ¼ 8.5 Hz, 2H, C6H4), 7.11 (d, J ¼ 8.5 Hz, 2H, C6H4). 13C NMR (CDCl3):
t
d
15.4 (CH3), 27.1 (6 CH3, Bu), 28.1 (CH2), 39.1 (2C), 68.6 (2 CH,
10 (0.594 g, 1 mmol) was dissolved into 15 mL of THF and 15 mL
of diethyl ether. A solution of citric acid (0.105 g, 0.5 mmol), in THF
(5 mL) was added dropwise into the first solution. An orange
precipitate was immediately formed. After stirring for 20 min, the
mixture was filtered under argon and the orange solid obtained was
washed with 3 ꢂ 5 mL of diethyl ether and dried under vacuum.
C5H4), 69.5 (2 CH, C5H4 þ 5 CH, Cp), 87.2 (Cipso), 121.1 (2 CH, C6H4),
121.3 (2 CH, C6H4), 130.4 (2 CH, C6H4), 131.0 (2 CH, C6H4), 136.2 (C),
138.4 (C), 141.5 (C), 141.7 (C), 149.4 (C), 149.5 (C), 177.0 (2 CO). IR
(KBr, n
cmꢃ1): 3093, 2970, 2931, 2873 (CH2, CH3), 1751 (CO). MS (EI,
70 eV) m/z: 592 [M]þ., 527, 443, 121 [CpFe]þ, 57 [tBu]þ. Anal. Calcd.
for C36H40FeO4: C, 72.97; H, 6.8. Found: C, 73.36; H, 7.01.
0.338 g of 27 were obtained (84% yield). 1H NMR (CD3OD):
d 0.99 (t,
J ¼ 7.4 Hz, 3H, CH3), 1.86 (broad m, 4H, 2 CH2), 2.61 (q, J ¼ 7.4 Hz, 2H,
CH2), 2.66 (d, J ¼ 15.3 Hz, 2H, CH2), 2.75 (d, J ¼ 15.3 Hz, 2H, CH2),
2.86 and 2.87 (2 s, 12H, 2 NMe2Hþ), 3.30 (broad m, 4H, 2 CH2N),
3.87 (m, 2H, C5H4), 4.02 (m, 6H, 2 CH2O þ C5H4), 4.08 (s, 5H, Cp),
6.75 (d, J ¼ 8.1 Hz, 2H, C6H4), 6.90 (m, J ¼ 8.1 Hz, 4H, C6H4), 7.08 (d,
4.9. 1,1-Bis-(4-palmitoyloxyphenyl)-2-phenyl-but-1-ene, 23
In a Schlenk tube, diphenol 18 (0.95 g, 3 mmol) was dissolved in
anhydrous THF, then sodium hydride (0.30 g, 7.55 mmol, 60%
suspension in oil) was added. After 10 min under stirring, palmitoyl
chloride (1.814 g, 2 mL, 6.6 mmol) was added and the mixture was
stirred for 3 h. 5 mL of ethanol was added and the stirring was
continued for 1 h in order to destroy the excess of palmitoyl chloride.
The mixture was poured into water, extracted twice with dichloro-
methane and concentrated under reduced pressure. Then the
residue was chromatographed on silica gel column using dichloro-
methane/petroleum ether 1/1 as an eluent. The product was
recrystallized from diethyl ether to yield 23 in a 96% yield as a white
J ¼ 8.1 Hz, 2H, C6H4). 13C NMR (CD3SOCD3):
d 15.3 (CH3), 24.3 (2
CH2), 42.8 (2 NMe2Hþ), 44.3 (2 CH2 citrate), 54.5 (2 CH2N), 66.9 (2
CH2O), 67.8 (2 CH, C5H4), 68.6 (2 CH, C5H4), 69.0 (5 CH Cp), 71.4 (Cq,
citrate), 86.0 (Cipso C5H4), 114.1 (2 ꢂ 2 CH, C6H4), 129.9 (2 CH, C6H4),
130.3 (2 CH, C6H4), 136.2 I, 136.4 I, 136.9 I, 137.1 I, 156.6 (2C), 171.5
(2 ꢂ CO), 176.9 (CO). IR (KBr,
n
cmꢃ1): 3421 (OH), 3032, 2962, 2877,
(CH2, CH3), 1720 (CO). 27 crystals contain traces of solvents (THF
and diethyl ether).
solid. Mp: 75 ꢀC 1H NMR (CDCl3):
d
0.81 (t, J ¼ 7.0 Hz, 6H, CH3), 0.85
4.12. In vitro antibacterial activity
(t, J ¼ 7.4 Hz, 3H, CH3), 1.09e1.41 (m, 48H, CH2), 1.53e1.76 (m, 4H,
CH2), 2.32e2.55 (m, 6H, CH2), 6.65 (d, J ¼ 8.7 Hz, 2H, C6H4), 6.78 (d,
J ¼ 8.7 Hz, 2H, C6H4), 6.96e7.20 (m, 9H, Harom). 13C NMR (CDCl3):
Three microorganisms, obtained from “Biotechnology Center of
Sfax”, were used: P. aeruginosa ATCC 15442, S. aureus ATCC 9144
and C. albicans. ATCC 10231. Antimicrobial activity was determined
by the tube dilution method. Two fold dilutions of the compound
were prepared in the Plate count agar liquid. A suspension of the
standard microorganisms, prepared from 24 h cultures of bacteria
in the liquid plate count agar at a concentration of 105 CFU/mL
(Colony Forming Unit.mLꢃ1), were added to each dilution in a 1:1
ratio. Growth (or lack thereof) of the microorganisms was deter-
mined visually after incubation for 24 h at 30 ꢀC. The lowest
d
13.5 (CH3),14.1 (2 CH3), 22.7 (2 CH2), 25.0 (2 CH2), 29.1 (2 CH2), 29.2
(CH2), 29.3 (2 CH2), 29.4 (2 CH2), 29.5 (2 CH2), 29.7 (6 ꢂ 2 CH2), 31.9
(2 CH2), 34.4 (2 CH2), 120.4 (2 CH, C6H4), 121.2 (2 CH, C6H4), 126.3
(CH, C6H5), 127.9 (2 CHarom), 129.6 (2 CHarom), 130.5 (2 CHarom), 131.7
(2 CHarom),137.0 (C), 140.2 (C),140.6 (C),141.8 (C),143.0 (C),148.7 (C),
149.5 (C), 172.1 (CO), 172.3 (CO). IR (KBr,
n
cmꢃ1): 3047, 2916, 2850
(CH2, CH3), 1759 (CO). MS (CI, NH3) m/z: 792 [M]þ, 810 [M þ NH4]þ.
Anal. Calcd. for C54H80O4: C, 81.76; H, 10.16. Found: C, 81.51; H, 10.37.

M. El Arbi et al. / Journal of Organometallic Chemistry 696 (2011) 1038e1048
[3] R.H. Fish, G. Jaouen, Organometallics 22 (2003) 2166e2177.
1047
concentration at which there was no visible growth (turbidity) was
taken as the MIC. Then from each tube, one loopful was cultured on
Plate count agar and incubated for 24 h at 30 ꢀC. The lowest
concentration of the compound supporting no colony formation
was defined as the MBC. Doxycycline was used as standard anti-
biotic. Solutions of the test compounds and doxycycline were
prepared in ethanol at concentration of 2 mg mLꢃ1. The two fold
dilutions of the compounds were prepared (200, 100, 50, 25,
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compounds to be tested were prepared in DMSO just prior to use.
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We thank the Ministère de la Recherche and the Centre National
de la Recherche Scientifique for financial support, Mrs Barbara
McGlinchey for helpful discussions. M. El Arbi thanks the Ministère
de l’Enseignement Supérieur et de la Recherche Scientifique of
Tunisia for financial support and ISET-Sfax for technical support.
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