Synthesis and characterization of new ferrocenyl compounds with different alkyl chain lengths and functional groups to target breast cancer cells

Article abstract of DOI:10.1016/j.jorganchem.2013.07.031

A new family of organometallic compounds bearing chains of different lengths and with different functional groups was synthesized and evaluated against triple negative MDA-MB-231 and hormonedependent MCF-7 breast cancer cells. Biological results comparing suberamides (six-methylene chain length) and succinamides (two methylene chain length) showed that chain shortening does not dramatically impact on their antiproliferative effects. Cytotoxicity of primary amides is not dependent on chain length, as suberamide and succinamide showed almost identical activity against both types of breast cancer cells. However, the possibility that some of the cytotoxic activity of hydroxamides could be related to enzyme inhibition, e.g. histone deacetylase (HDAC) inhibition, is not excluded. This is based on the fact that compounds bearing a longer alkyl chain showed IC₅₀ values lower than those with shorter alkyl chains. Succinic and adipic carboxylic acids and a succinimide were also tested and they also showed cytotoxic activity. Interestingly, succinimide was the most active compound against hormonedependent MCF-7 breast cancer cells, presumably owing to an antagonist effect with the alpha form of the estrogen receptor (ERα). Some new and interesting side chain influences related to antiproliferative effects can therefore be observed.

Full text of DOI:10.1016/j.jorganchem.2013.07.031

Journal of Organometallic Chemistry 751 (2014) 610e619
Contents lists available at ScienceDirect
Journal of Organometallic Chemistry
journal homepage: www.elsevier.com/locate/jorganchem
Synthesis and characterization of new ferrocenyl compounds with
different alkyl chain lengths and functional groups to target breast
cancer cells
*
**
José de Jesús Cázares-Marinero, Siden Top , Gérard Jaouen
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
a r t i c l e i n f o
a b s t r a c t
Article history:
A new family of organometallic compounds bearing chains of different lengths and with different
functional groups was synthesized and evaluated against triple negative MDA-MB-231 and hormone-
dependent MCF-7 breast cancer cells. Biological results comparing suberamides (six-methylene chain
length) and succinamides (two methylene chain length) showed that chain shortening does not
dramatically impact on their antiproliferative effects. Cytotoxicity of primary amides is not dependent on
chain length, as suberamide and succinamide showed almost identical activity against both types of
breast cancer cells. However, the possibility that some of the cytotoxic activity of hydroxamides could be
related to enzyme inhibition, e.g. histone deacetylase (HDAC) inhibition, is not excluded. This is based on
the fact that compounds bearing a longer alkyl chain showed IC50 values lower than those with shorter
alkyl chains. Succinic and adipic carboxylic acids and a succinimide were also tested and they also
showed cytotoxic activity. Interestingly, succinimide was the most active compound against hormone-
dependent MCF-7 breast cancer cells, presumably owing to an antagonist effect with the alpha form
Received 12 June 2013
Received in revised form
8 July 2013
Accepted 9 July 2013
Keywords:
Anticancer activity
Ferrocene
Medicinal chemistry
MCF-7
Organometallics
Triple negative breast cancer cells
of the estrogen receptor (ER
a). Some new and interesting side chain influences related to anti-
proliferative effects can therefore be observed.
Ó 2013 Elsevier B.V. All rights reserved.
1. Introduction
drug used to treat primary cutaneous T-cell lymphoma [4,5] while
FcTAM3 and derived compounds are organometallic tamoxifen-
type species which proved to be more active than the corre-
sponding organic analogs against hormone-dependent MCF-7
breast cancer cells. Moreover, they were also found to be strongly
cytotoxic against triple negative MDA-MB-231 breast cancer cells,
where tamoxifen (TAM) and related organic compounds are
completely inactive under the same conditions [6].
Biological studies of the resulting organometallic hybrid FcTAM-
SAHA on triple negative MDA-MB-231 breast cancer cells showed
that the combination of both features gave them beneficial effects
in terms of antiproliferative activity. Analyzing their cytotoxicities
separately, one can see that, in the case of SAHA, the presence of the
organometallic moiety 2-ferrocenyl-1-phenylbut-1-en-1-yl, as a
substituent on the 4 position of its cap, enhanced its activity more
Organometallic compounds show particular physicochemical
properties depending on the nature of the metal moieties. Their use
in catalysis is very well known and their application in drug syn-
thesis constitutes one of the most common practices of organic
chemists. However, at the end of the last century, it was demon-
strated that these compounds could themselves be used to treat
diseases [1]. Redox properties and 3D structures of organometallic
compounds are some of the countless features that have attracted
the attention of researchers to design new drug candidates and to
explore new mechanisms of action [2]. Recently, we have incor-
porated the pharmacophore of the known drug (N1-hydroxy-N8-
phenylsuberamide) SAHA into the ferrocifen (FcTAM3) molecule as
a strategy to explore the mechanism of action of ferrocifen de-
rivatives (Fig.1) [3]. SAHA is a histone deacetylase inhibitor (HDACi)
than five times (from IC50 ¼ 3.64
mM to 0.70 mM) while in the case of
FcTAM3, the presence of the 8-hydroxyamino-8-oxooctanamido
group instead of its dimethylaminoalkoxy chain made it over
* Corresponding author. Tel.: þ33 1 44 27 66 99.
three times more effective (from IC50 ¼ 2.62
mM to 0.70 mM).
Regarding hormone-dependent MCF-7 breast cancer cells, the
** Corresponding author. Tel.: þ33 1 43 26 95 55.
E-mail addresses: siden-top@chimie-paristech.fr, siden-top@enscp.fr (S. Top),
gerard-jaouen@chimie-paristech.fr (G. Jaouen).
positive effect of the structural combination of SAHA and FcTAM3
0022-328X/$ e see front matter Ó 2013 Elsevier B.V. All rights reserved.
http://dx.doi.org/10.1016/j.jorganchem.2013.07.031

J.deJ. Cázares-Marinero et al. / Journal of Organometallic Chemistry 751 (2014) 610e619
611
Fig. 1. Structures of FcTAM3, SAHA and FcTAM-SAHA with their corresponding IC50 values against triple negative MDA-MB-231 breast cancer cells.
was only observed in the case of the latter. Such modification more
than doubled the activity of FcTAM3 (from IC50 ¼ 4.41 M to
2.01 M). However, SAHA modification did not increase its anti-
proliferative activity against MCF-7, since on these hormone-
dependent breast cancer cells the organometallic derivative
FcTAM-SAHA remained little more than half as active as SAHA
Data suggested that there was no correspondence between their
m
HDACi activity and their cytotoxic effects against a mouse eryth-
roleukemia cell line [13]. The chain length increase, from four
carbons to ten, resulted in greater antiproliferative activity but a
decline in their HDACi effects, suggesting that they may differ in
their mechanism of action. Other studies on derivatives of SAHA
have explored the chain-length dependence of enzymatic activity
[14]. Biological evaluations of compounds combining the bioavail-
ability of short-chain fatty acids such as butyric acid with the
binding ability of the hydroxamic function in SAHA showed, with
modest results, that the most effective species consisted of com-
pounds bearing longer chains with hydroxamic acid groups [15].
Finally, some studies seeking potent multi-acting molecules tar-
geting HDAC, the epidermal growth factor receptor (EGFR) and the
human epidermal growth factor receptor 2 (HER2) at the same time
for the treatment of cancer, showed that chain length is an
important motif for HDAC inhibition, the eight-carbon long-chain
analogs being the most active agents [16,17]. Our group has also
reported the effects of side-chain modification in structureeactiv-
ity relationship studies of the ferrocifen family [6,18].
m
(IC50 ¼ 2.01
mM for FcTAM-SAHA vs 1.04 mM for SAHA in this study).
Interestingly, this behavior on MCF-7 was also reported for two
other organometallic SAHA analogs, the N1-ferrocenyl-N8-hydrox-
ysuberamide (JAHA) prepared by Spencer et al. [7] and the tri-
carbonyl[(8-hydroxyamino-8-oxooctanamido)-h
5-cyclo-
pentadienyl]rhenium(I) prepared by Can et al. [8] (Fig. 2).
On the other hand, both SAHA and FcTAM-SAHA were shown to
chelate metal ions such as Fe3þ and they are believed to bind Zn2þ
as well [9]. This feature plays an important role in biochemistry
since these chelating effects could be exploited to inactivate en-
zymes [10]. For example FcTAM-SAHA was shown to be active as
HDACi [3]. In this context, it is important to state that some
members of the JAHA family, which are also ferrocenic, were re-
ported to be effective HDACi against some enzyme isoforms [11].
In an attempt to determine whether the N-hydroxamide func-
tion on FcTAM-SAHA was structurally necessary to produce cyto-
toxic effects, and thus to estimate the effect of the SAHA
pharmacophore in the hybrid molecule, the primary amide FcTAM-
PSA (Fig. 3) was also synthesized and evaluated. Surprisingly, this
molecule also showed strong antiproliferative activity against both
types of breast cancer cells, with IC50 values even slightly lower
than those of FcTAM-SAHA. Further, its organic analog, the N-
phenylsuberamide (PSA) was very far from achieving the same
The aim of the present investigation is to explore the impact of
this effect in ferrocenyl hydroxy and primary amides derived from
adipic and succinic acids on their antiproliferative activity against
breast cancer cells. Carboxylic acids and a succinimide are also
included in this study in order to evaluate other chemical
functionalities.
2. Results and discussion
cytotoxic effects even at higher concentrations (>10
mM).
2.1. Synthesis of adipic compounds
Interestingly, both PSA and FcTAM-PSA exhibited neither
chelating capacities nor any HDACi activity, seeming to indicate
that cytotoxic effects are not strongly dependent on the function-
alization on the lateral alkyl chain of both suberamides to produce
almost the same response. This also means that the two com-
pounds may share at least one particular mechanistic feature which
is responsible for their strong cytotoxic effects. This would correlate
with the fact that both FcTAM-SAHA and FcTAM-PSA were able to
generate the expression of the tumor suppressor gene p21 [3].
On the other hand, it is possible to find in the literature that one
of the most common strategies in structuraleactivity relationship
studies of biologically active molecules is chain length modifica-
tion. For example, an idoxifene analog bearing an alkyl chain
modified by the presence of eight methylene groups instead of two
did not show any improvements in terms of in vitro anti-
estrogenicity or antitumor activity [12]. However, it has been sug-
gested that the chemical nature of the residue located at the end of
the long side chain of other related antiestrogens may be an
important factor. Another example is the evaluation of 4-
phenylbutyric acid analogs, which were believed to act as HDACi.
The synthesis of the three adipic derivatives that were tested in
biological assays was performed as described in the literature
(Scheme 1) [3]. Aniline 1 was previously obtained as a mixture of Z
and E isomers (Z/E ratio ¼ 85/15) from a McMurry cross coupling
between 4-aminobenzophenone and propionylferrocene [3,19]. To
obtain carboxylic acid 2, aniline 1 reacted with adipoyl chloride
(ClCOCH2CH2)2) in 20 min at room temperature to afford 51% of
product. As reported, lower temperatures did not significantly in-
crease the yield, and bisamide 3 is always obtained as byproduct.
After aniline 1 was consumed, the mixture was allowed to react
with sodium hydroxide (NaOH) to ensure that chlorides trans-
formed into carboxylates and consequently acidification was
needed to favor the soluble form in organic solvents for extraction.
To obtain hydroxamide 4, a solution of hydroxylamine was first
prepared at 0 ꢀC from 4 equivalents of hydroxylamine hydrochlo-
ride (NH2OH$HCl) and 8 equivalents of potassium hydroxide (KOH).
Simultaneously, carboxylic acid 2 reacted with 2 equivalents of
ethyl chloroformate (ClCO2Et) and 2.5 equivalents of triethylamine
(TEA) to result in a carbonate intermediate. This latter was attacked

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Cázares-Marinero[3]
[2.01 µM/1.04 µM]
Spencer[7]
Can[8]
[2.44 µM/0.75 µM]
[11.4 µM/3.74 µM]
Fig. 2. Chemical structures of three organometallic SAHA derivatives with their corresponding reported IC50 values vs the reported IC50 value for SAHA [compound/SAHA] in each
study against hormone-dependent MCF-7 breast cancer cells.
by the freshly prepared hydroxylamine to afford 4. The relatively
low yield of the desired product (36%) can be explained by the
competitive reaction of MeOH to form the ester from the activated
2 in basic conditions, as was also observed for other series [20].
Finally, to obtain primary amide 5, the same activation step of
carboxylic acid 2 was needed before allowing it to react with an
excess of sodium amide (NaNH2). This time, compound 5 was ob-
tained in excellent yield (93%). All the products of this adipic series
(2e5) were characterized by conventional techniques.
synthetic protocol of 4 but starting from carboxylic acid 7 to afford
9 in a yield of 30%.
Finally, since succinamide 10 could not be obtained by the direct
nucleophilic attack of NaNH2 on succinimide 6, the classic protocol
was performed from 7, activation with ethyl chloroformate fol-
lowed by reaction with NaNH2 to obtain 10 in 36%. The fact that
reaction with NaNH2 did not proceed could be explained by the
strong basicity of the amide anion (NH-2) over its poor nucleophi-
licity and because succinimide could be less electrophilic than the
activated carboxylate. Instead of obtaining 10 in this attempt, car-
boxylic acid 7 was the identified product. This could come from the
HO- generation from water in the work-up by the basic NaNH2 to
open the succinimide ring.
2.2. Synthesis of succinic compounds
The pathway for the synthesis of the succinic compounds
intended for biological evaluations was different from the adipic
series since reactivity of aniline
1
with succinyl chloride
2.3. Antiproliferative activity of adipamides against breast cancer
cells
((ClCOCH2)2) preferentially formed the succinimide 6 instead of
carboxylic acid 7. This could be explained by the preference of
forming the stable five-membered cycle via the double nucleophilic
attack of aniline 1 to succinyl chloride. Thus, given that low tem-
peratures did not significantly improve the yield of carboxylic acid
7, aniline 1 was allowed to react with succinyl chloride at room
temperature. After purification, the nature of the products
observed by TLC during the reaction was established as the succi-
nimide 6, carboxylic acid 7 and bisamide 8 (Scheme 2). Since re-
action produced carboxylic acid in low yields, we performed the
ring opening of succinimide 6 with NaOH under mild conditions to
obtain the desired carboxylic acid 7 in excellent yield (96%). In an
effort to explore the possibility of optimizing the production of 7,
bisamide 8 was hydrolyzed with hydrochloric acid (HCl) in an
acetone/water mixture to afford quantitatively after 1 h of reflux
carboxylic acid 7 and aniline 1. Having observed the good response
of succinimide to nucleophiles such as hydroxide anion (HOꢁ) we
explored the possibility of allowing it to react with NH2OH to
produce hydroxamide 9. Thus, 6 reacted with an excess of a basic
solution of hydroxylamine as previously described to afford 9 in a
yield of 19%. This product can also be obtained following the
Cytotoxicity studies showed that suberamides FcTAM-SAHA
and FcTAM-PSA which bear an alkyl chain longer than adipamides
4 and 5 remained more active against both breast cancer cell lines,
respectively (Table 1 and Chart 1). On triple negative MDA-MB-231
breast cancer cells, for example, it may be seen that this lack of two
ꢀ
methylene groups (4.5 A, approximately) on the lateral alkyl chain
of hydroxamide 4 impacted almost fivefold on its antiproliferative
activity in comparison with FcTAM-SAHA, while on amide 5 it was
almost seven times in comparison with FcTAM-PSA. On hormone-
dependent MCF-7 breast cancer cells, this phenomenon is also true,
with almost double the activity.
Interestingly, the attenuated effect (about threefold) observed in
the cytotoxicity of suberamides against MCF-7 in comparison with
MDA-MB-231 was not present in adipamides. It was shown for
suberic compounds FcTAM-SAHA and FcTAM-PSA that estrogenic
effects are developed at concentrations (around 0.01
mM) lower
than their IC50 values [3]. This hormonal effect could favor cell
proliferation and consequently somewhat counteract their cyto-
toxic effects. However, in the case of adipic compounds this effect
Fig. 3. Chemical structures of primary suberamides FcTAM-PSA and PSA with IC50 values against breast cancer cells.

J.deJ. Cázares-Marinero et al. / Journal of Organometallic Chemistry 751 (2014) 610e619
613
Scheme 1. Synthesis of adipic derivatives. Reagents and conditions: [i] (ClCOCH2CH2)2, DCM, rt, 20 min (51%). [ii] ClCO2Et, TEA, THF, 0 ꢀC, 15 min [iii] NH2OH$HCl, KOH, MeOH, 0 ꢀC,
20 min then 2.5 h (36%). [iv] NaNH2, rt, 30 min (93%).
Scheme 2. Synthesis of succinic derivatives. Reagents and conditions: [i] (ClCOCH2)2, THF, rt, 30 min, (48%). [ii] NaOH, MeOH, rt, 15 min (96%). [iii] HCl, (CH3)2CO/H2O, reflux, 1 h. [iv]
ClCO2Et, TEA, THF, 0 ꢀC, 15 min [v] NH2OH$HCl, KOH, MeOH, 0 ꢀC, 20 min then 2 h (30%). [vi] NaNH2, rt, 30 min (36%). [vii] Excess of NH2OH, 20 min, 19%.

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Table 1
IC50
(
m
M) for adipic (n ¼ 4) and suberic (n ¼ 6) amides against breast cancer cell línes.a
n
Compound
MDA-MB-231
MCF-7
Compound
MDA-MB-231
MCF-7
6
4
FcTAM-SAHA
4
0.70 ꢂ 0.07
3.31 ꢂ 0.46
2.01 ꢂ 0.07
3.71 ꢂ 0.76
FcTAM-PSA
5
0.50 ꢂ 0.11
3.35 ꢂ 0.68
1.81 ꢂ 0.88
3.14 ꢂ 0.43
a
Measurements were performed in duplicate after 72 h. Values are reported with SD.
methylene groups in comparison with 5. This could indicate that
primary succinamide 10 may show a particular behavior different
from that of adipamides. We can take as an example the study on
phenylbutyrate derivatives [13] that suggest that phenylbutyrate
was more effective than other acids bearing longer chains. This is
also consistent with the activities observed in the present study for
succinic derivatives with shorter chain lengths but more cytotoxic
effects than adipic ones.
MDA-MB-231
MCF-7
5
4
3
2
1
0
5
4
3
2
1
0
2.5. Antiproliferative activity of succinimide and carboxylic acids
suberic adipic suberic adipic
suberic adipic suberic adipic
Succinimide 6 and carboxylic acids 2 and 7 were also tested
against both breast cancer cell lines (Table 3 and Chart 3). Inter-
estingly, with more modest IC50 values than the amides, carboxylic
acids were also cytotoxic against cancer cells. Contrary to the
behavior of adipic and succinic amides, carboxylic acid 2 bearing a
longer chain than 7 seems to be the more cytotoxic of the two. In
both carboxylic compounds 2 and 7, we can see a similar cytotox-
icity against both breast cancer cell lines. However, succinimide 6
was, interestingly, more active than either 2 or 7. Moreover, it was
the most active compound of all the three series e suberic, adipic
and succinic derivatives e against hormone-dependent MCF-7
hydroxamides
primary amides
hydroxamides
primary amides
Chart 1. IC50 M) for suberic and succinic amides against MDA-MB-231 and MCF-7
(
m
breast cancer cells.
was not present, with equal cytotoxicity on both hormone-
dependent and hormone-independent breast cancer cells. Given
the estrogenicity of related compounds and the fact that one of the
major differences between MDA-MB-231 and MCF-7 is the pres-
ence of ERa, adipic compounds may be less estrogenic but less
cytotoxic as well.
breast cancer cells with an IC50 value of 1.06
mM. The crystal
structure of hER LBD bound to 4-OHTAM, determined by Shiau
a
2.4. Antiproliferative activity of succinamides against breast cancer
cells
et al. [21] has shown that the dimethylamino chain is stabilized in
the active site by contacts with Thr-347, Ala-350 and Trp-383. The
good activity of 6 against MCF-7 cells could be explained by the
potential ability of the succinimide group to bind to these amino
acids and by the steric effect of succinimide unit.
In these three examples, it can be seen that shortening the chain
length did not dramatically modify the activity of compounds as it
was observed in the reported study of multifunctional species to-
wards HDAC, EGFR and HER2 demonstrating that EGFR and HER2
inhibition were largely unaffected by the change in carbon chain
length and concluding that side chain on the molecular structure of
such compounds is not critical for EGFR/HER2 inhibition activity
The two ferrocenyl succinamides were shown to be anti-
proliferative against both breast cancer cell lines (Table 2 and Chart
2). In the case of succinic hydroxamide 9, the attenuation of cyto-
toxicity due to the chain shortening was also true as it occurred
with adipic hydroxamide 4. Surprisingly, primary succinamide 10
was as active as primary suberamide FcTAM-PSA, even though it
lacks four methylene groups in comparison with this latter. More-
over, it was six times more active than adipamide 5 against MDA-
MB-231 and twice as active against MCF-7, which lacks two
Table 2
IC50
(
m
M) for succinic (n ¼ 2) and suberic (n ¼ 6) amides against breast cancer cell línes.a
n
Compound
MDA-MB-231
MCF-7
Compound
MDA-MB-231
MCF-7
6
2
FcTAM-SAHA
9
0.70 ꢂ 0.07
1.43 ꢂ 0.05
2.01 ꢂ 0.07
2.78 ꢂ 0.82
FcTAM-PSA
10
0.50 ꢂ 0.11
0.54 ꢂ 0.11
1.81 ꢂ 0.88
1.30 ꢂ 0.18
a
Measurements were performed in duplicate after 72 h. Values are reported with SD.

J.deJ. Cázares-Marinero et al. / Journal of Organometallic Chemistry 751 (2014) 610e619
615
3. Conclusions
MDA-MB-231
MCF-7
5
4
3
2
1
0
5
We have synthesized seven new ferrocenyl compounds bearing
different chain lengths and functional groups. All of them showed
strong antiproliferative activities against triple negative MDA-MB-
231 and hormone-dependent MCF-7 breast cancer cell lines with
IC50 values ranging from 0.5 mM to 4.12 mM. Primary amides FcTAM-
PSA and 10 were the most cytotoxic compounds of all the three
4
3
2
1
0
series (suberic, adipic and succinic) against MDA-MB-231 cells,
with IC50 values of 0.50 mM and 0.54 mM, respectively; while suc-
cinimide 6 was the most active compound against hormone-
dependent MCF-7 breast cancer cells. This study showed that
MCF-7 and MDA-MB-231 are differently sensitive to the effects of
compounds. Cytotoxic activities of primary amides are not strongly
affected by chain length shortening. It seems that some of the
suberic succinic suberic succinic
suberic succinic suberic succinic
hydroxamides primary amides
hydroxamides
primary amides
Chart 2. IC50 (mM) for succinic and suberic amides against MDA-MB-231 and MCF-7
breast cancer cells.
Table 3
IC50
(
m
M) of acids and succinimide breast cancer cell línes.a
2
7
6
MDA-MB-231
MCF-7
MDA-MB-231
MCF-7
MDA-MB-231
MCF-7
1.89 ꢂ 0.01
2.69 ꢂ 0.78
3.48 ꢂ 0.76
4.12 ꢂ 0.09
1.74 ꢂ 0.21
1.06 ꢂ 0.06
a
Measurements were performed in duplicate after 72 h. Values are reported with SD.
[16]. This is also consistent with our results, showing that chain
shortening does not significantly affect the cytotoxicity of products
and even the less cytotoxic products in this paper (7, for example,
cytotoxic effects of hydroxamides could be related to enzymatic
inhibition processes. This could be of interest in our efforts to
identify the target proteins for these species.
showed an IC50 ¼ 4.12
mM against MCF-7) are antiproliferative
species against breast cancer cells. We have already reported that
HDAC are not the principal targets of such compounds. This study
might confirm that hypothesis. However, it seems that there is still
the possibility that some of the cytotoxic effects of hydroxamides
could be related to enzymatic inhibition processes. This opens the
possibility of study of the above compounds on diverse biological
targets.
4. Experimental
4.1. General procedures
All reagents and solvents were obtained from commercial sup-
pliers and used without further purification. Tetrahydrofuran (THF)
was distilled from Na/benzophenone and dichloromethane (DCM)
from P2O5, both under argon atmosphere. Thin layer chromatog-
raphy (TLC) was performed on silica gel 60 GF254. Column chro-
MDA-MB-231
MCF-7
matography was performed on silica gel Merck 60 (40e63 mm). All
5
4
3
2
1
0
5
4
3
2
1
0
of the products were characterized by conventional techniques.
Infrared (IR) spectra were recorded on a Jasco FT/IR-4100 Fourier
transform infrared spectrometer by potassium bromide (KBr) pel-
lets technique and all data are expressed in wave numbers (cmꢁ1).
Melting points (mp) were obtained with a Kofler device and are
uncorrected. 1H and 13C NMR spectra were recorded on a 300 MHz
Bruker spectrometer and chemical shifts (d) are expressed in ppm.
The mass spectra (MS) were obtained on a DSQII and ITQ 1100
Thermo Scientific spectrometer for both electronic impact (EI) and
chemical ionization (CI) methods and API 3000 PE Sciex Applied
Biosystems for electrospray ionization (ESI) method. Purity of >99%
was confirmed by analytical reverse phase HPLC with a column
2
7
2
7
Kromasil C18, 10
mixtures of MeOH/H2O as mobile phase, flow rate ¼ 1 mL/min,
¼ 254 nm. Elemental analyses were performed by the Laboratory
of Microanalysis at ICSN of CNRS at Gif sur Yvette, France.
mm, L ¼ 25 cm, D ¼ 4.6 mm using MeOH and
carboxylic acids succinimide
carboxylic acids succinimide
l
Chart 3. IC50
MCF-7 breast cancer cells.
(mM) for succinimide and carboxylic acids against MDA-MB-231 and

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4.2. Synthesis
Bisanilide 3 was identified as byproduct for 2 synthesis. mp:
96e98 ꢀC. 1H-NMR (300 MHz, (CD3)2SO, ppm): major isomer (68%),
0.98 (t, J ¼ 7.4 Hz, 6H: a), 1.55e1.70 (m, 4H: p), 2.24e2.38 (m, 4H:
o), 2.48 (q, J ¼ 7.4 Hz, 4H: b), 3.88 (3.77 for minor isomer, t,
), 4.12 (s,
4.2.1. 6-[4-(2-ferrocenyl-1-phenylbut-1-en-1-yl)anilino]-6-
oxohexanoic acid, 2
d
J ¼ 1.9 Hz, 4H:
a
), 4.10 (4.07 for minor, t, J ¼ 1.9 Hz, 4H:
b
10H: Cp), 6.96 (7.04 for minor, d, J ¼ 8.5 Hz, 4H: j), 7.21 (d, J ¼ 7.5 Hz,
4H: f), 7.24 (t, J ¼ 7.5 Hz, 2H: h), 7.34 (t, J ¼ 7.5 Hz, 4H: g), 7.49 (7.56
for minor, d, J ¼ 8.5 Hz, 4H: k), 9.88 (9.91 for minor, s, 1H: m). 13C-
NMR (75 MHz, (CD3)2SO, ppm): major isomer,
d
15.4 (a), 24.9 (p),
27.1 (b), 36.3 (o), 68.1 (
b
), 68.8 (
a
), 69.1 (Cp), 85.5 ( ), 119.1 (k), 126.2
i
(h), 128.4 (129.1 for E, g), 128.8 (129.2 for E, f), 129.5 (j), 136.6 (c),
137.0 (d), 137.6 (l), 139.1 (i), 144.4 (e), 171.0 (n). IR (KBr, ymax/cmꢁ1):
3297 (NeH stretch), 3093, 3040 (CAreH stretch), 2927, 2866 (CAlke
H stretch), 1662 (NC]O stretch), 1593 (CAr]CAr stretch), 1520 (Ne
H bend), 1401 (CeN stretch). MS (CI, m/z): 925 [MH]þ, 408 [FPBA-
H]þ. Anal. Calc. for C58H56Fe2N2O2$3H2O (%): C, 71.17; H, 6.38; N,
2.86. Found: C, 70.99; H, 6.43; N, 2.57. HPLC (RT, min): 8.52 min
(MeOH).
A solution of aniline 1 (5.53 mmol, 2.25 g) in 30 mL of DCM was
slowly added at room temperature into a stirred solution of
(11.05 mmol,1.6 mL) adipoyl chloride in 10 mL of DCM. After 20 min
of stirring, the mixture was poured into an aqueous solution of
sodium hydroxide (NaOH) and then it was slightly acidified with a
10% aqueous solution of hydrochloric acid (HCl). The product was
extracted with ethyl acetate (AcOEt), the organic layer was dried
over magnesium sulfate (MgSO4), filtered and evaporated. The
crude product was separated by column chromatography using a
1:1 mixture of hexane and AcOEt. The first fraction was identified as
the byproduct bisamide 3. The last fraction was the carboxylic acid
2. Thus,1.50 g (51%) of 2 were obtained as an orange-red solid in a Z/
E isomer ratio ¼ 78/22. mp: 85e87 ꢀC. 1H-NMR (300 MHz,
4.2.3. N1-[4-(2-ferrocenyl-1-phenylbut-1-en-1-yl)phenyl]-N6-
hydroxyadipamide, 4
(CD3)2SO, ppm): Z isomer,
a),1.42e1.67 (m, 4H: q, p), 2.18e2.36 (m, 4H: r, o), 2.48 (q, J ¼ 7.4 Hz,
2H: b), 3.84 (3.78 for E, t, J ¼ 1.9 Hz, 2H: ), 4.11 (4.07 for E, t,
d
0.99 (1.00 for E isomer, t, J ¼ 7.4 Hz, 3H:
a
J ¼ 1.9 Hz, 2H: ), 4.12 (s, 5H: Cp), 6.96 (7.04 for E, d, J ¼ 8.5 Hz, 2H:
b
j), 7.21 (d, J ¼ 7.5 Hz, 2H: f), 7.25 (t, J ¼ 7.5 Hz, 1H: h), 7.34 (t,
J ¼ 7.5 Hz, 2H: g), 7.49 (7.56 for E, d, J ¼ 8.5 Hz, 2H: k), 9.86 (9.89 for
E, s, 1H: m), 12.04 (s, 1H: x). 13C-NMR (75 MHz, (CD3)2SO, ppm): Z
A
solution of hydroxylamine hydrochloride (NH2OH$HCl,
4.0 mmol, 0.278 g) in 10 mL of methanol (MeOH) was added to a
stirred solution of potassium hydroxide (KOH, 8.0 mmol, 0.448 g) in
10 mL of MeOH at 0 ꢀC. After it was stirred for 15 min, the precipitate
was removed and the filtrate was placed in a flask. In another flask, to
a solution of 2 (1.0 mmol, 0.535 g) in 15 mL of anhydrous THF, cooled
to 0 ꢀC, ethyl chloroformate (ClCO2Et, 2.0 mmol, 0.19 mL) and trie-
thylamine (TEA, 2.5 mmol, 0.35 mL) were added and the mixture was
stirred for 15 min and filtered. The filtrate was added to the freshly
prepared solution of NH2OH in MeOH. The resulting mixture was
stirred at room temperature for 2.5 h. After that, water was added and
the mixture was slightly acidified with HCl. The product was extrac-
ted with AcOEt, the organic layer was dried over MgSO4, filtered and
evaporated. The crude product was purified by column chromatog-
raphy using AcOEt as eluent. 0.200 g (36%) of 4 was obtained as an
orange-red solid in a Z/E isomer ratio ¼ 71/29. mp: 130e132 ꢀC. 1H-
isomer,
d
15.4 (a), 24.1 (q), 24.7 (p), 27.1 (b), 33.4 (r), 36.1 (o), 68.1
), 69.1 (Cp), 85.5 ( ), 119.1 (k), 126.2 (h), 128.4 (129.1 for E,
(b
), 68.8 (
a
i
g), 128.8 (129.2 for E, f), 129.5 (j), 136.6 (c), 137.0 (d), 137.5 (l), 139.1
(i), 144.3 (e),170.9 (n), 174.4 (s). IR (KBr, ymax/cmꢁ1): 3298 (NeH and
OeH stretch), 3093, 3051 (CAreH stretch), 2970, 2962 (CAlkeH
stretch), 1709 (OC]O stretch), 1662 (NC]O stretch), 1593 (CAr]CAr
stretch), 1523 (NeH bend), 1404 (CeN stretch), 1242 (CeO stretch).
MS (CI, m/z): 553 [MNH4]þ, 536 [MH]þ, 408 [FPBA-H]þ. Anal. Calc.
for C32H33FeNO3 (%): C, 71.78; H, 6.21; N, 2.62. Found: C, 71.16; H,
6.78; N, 2.22. HPLC (RT, min): 2.97 (MeOH), 4.17 (MeOH/H2O, 90:10).
4.2.2. N1,N6-bis[4-(2-ferrocenyl-1-phenylbut-1-en-1-yl)phenyl]
adipamide, 3
NMR (300 MHz, (CD3)2SO, ppm): Z isomer, d 0.99 (1.00 for E isomer, t,
J ¼ 7.4 Hz, 3H: a), 1.42e1.67 (m, 4H: q, p), 1.91e2.04 (m, 2H: r), 2.18e
2.36 (m, 2H: o), 2.48 (q, J ¼ 7.4 Hz, 2H: b), 3.83 (3.77 for E, t, J ¼ 1.9 Hz,
2H:
a
), 4.11 (4.08 for E, t, J ¼ 1.9 Hz, 2H:
b), 4.12 (s, 5H: Cp), 6.96 (7.04
for E, d, J ¼ 8.5 Hz, 2H: j), 7.21 (d, J ¼ 7.5Hz, 2H: f), 7.25 (t, J ¼ 7.5Hz,1H:
h), 7.35 (t, J ¼ 7.5 Hz, 2H: g), 7.48 (7.56 for E, d, J ¼ 8.5 Hz, 2H: k), 8.69 (s,
1H: w), 9.86 (9.89 for E, s, 1H: m), 10.37 (s, 1H: x). 13C-NMR (75 MHz,
(CD3)2SO, ppm): Z isomer,
d
15.4 (a), 24.9 (q, p), 27.1 (b), 32.2 (r), 36.2
), 69.1 (Cp), 85.5 ( ), 119.1 (k), 126.2 (h),
(o), 68.1 ( ), 68.8 (68.7 for E,
b
a
i
128.4 (129.1 for E, g),128.8 (129.2 for E, f),129.5 (j),136.6 (c),137.0 (d),
137.5 (l), 139.1 (i), 144.3 (e), 169.0 (s), 171.0 (n). IR (KBr, ymax/cmꢁ1):
3236(NeH and OeHstretch), 3101 (CAreHstretch), 2958, 2931 (CAlke
H stretch), 1643 (NC]O stretch), 1597 (CAr]CAr stretch), 1523 (NeH

J.deJ. Cázares-Marinero et al. / Journal of Organometallic Chemistry 751 (2014) 610e619
617
bend),1401 (CeN stretch). MS (ESI, m/z): 549 [M ꢁ H]ꢁ. Anal. Calc. for
A solution of 1 (5.13 mmol, 2.09 g) in 45 mL of THF was added in
15 min into a stirred solution of succinyl chloride (6.35 mmol,
0.7 mL) in 15 mL of anhydrous THF at room temperature. After
30 min of stirring, the mixture was poured into 50 mL of a saturated
aqueous solution of sodium bicarbonate (NaHCO3). The product
was extracted with AcOEt, the organic layer was dried over MgSO4,
filtered and evaporated. The crude was purified on a silica gel col-
umn using a 1:1 mixture of hexane and AcOEt as mobile phase. The
first fraction was identified as the bisamide 8, the second one was
the succinimide 6 and the last one was the carboxylic acid 7. Thus,
1.2 g (48%) of succinimide 6 were obtained as an orange-red solid in
a Z/E isomer ratio ¼ 72/28. mp : 89e90 ꢀC. 1H-NMR (300 MHz,
C
32H34FeN2O3$¼H2O (%):C, 69.25;H, 6.27;N, 5.05. Found: C, 69.51; H,
6.55; N, 5.05. HPLC (RT, min): 3.78 (MeOH), 7.85 (MeOH/H2O, 90/10).
4.2.4. N1-[4-(2-ferrocenyl-1-phenylbut-1-en-1-yl)phenyl]
adipamide, 5
(CD3)2SO, ppm): Z isomer,
a), 2.41e2.60 (q, J ¼ 7.4 Hz, 2H: b), 2.76 (2.78 for E, s, 4H: o), 3.85
),
d
1.01 (1.05 for E isomer, t, J ¼ 7.4 Hz, 3H:
(3.80 for E, t, J ¼ 1.9 Hz, 2H:
a
), 4.13 (4.10 for E, t, J ¼ 1.9 Hz, 2H:
b
4.16 (4.15 for E, s, 5H: Cp), 7.17 (s, 4H: k, j), 7.21e7.33 (t, 1H: h), 7.26
(d, J ¼ 7.5 Hz: f), 7.37 (t, J ¼ 7.5 Hz, 2H: g). 13C-NMR (75 MHz,
(CD3)2SO, ppm): Z isomer, d 15.4 (a), 27.1 (b), 28.4 (o), 68.2 (b), 68.8
(a), 69.1 (Cp), 85.0 (i),126.4 (h),126.9 (k),128.5 (129.0 for E, g),128.8
(129.1 for E, f), 129.4 (j), 130.6 (l), 136.3 (d), 137.4 (c), 143.9 (i), 144.0
(e), 176.9 (n). IR (KBr, ymax/cmꢁ1): 3086 (CAreH stretch), 2966, 2873
(CAlkeH stretch),1712 (C]O stretch),1381 (CeN stretch). MS (CI, m/
z): 507 [MNH4]þ, 490 [MH]þ. Anal. Calc. for C30H27FeNO2$½H2O
(%): C, 72.30; H, 5.66; N, 2.81. Found: C, 72.40; H, 5.56; N, 2.82. HPLC
(RT, min): 3.57 (MeOH), 7.13 (MeOH/H2O, 90/10).
To a solution of 2 (1.0 mmol, 0.535 g) in 10 mL of anhydrous THF,
cooled to 0 ꢀC, ClCO2Et (2.0 mmol, 0.19 mL) and TEA (2.5 mmol,
0.35 mL) were added and the mixturewasstirred for 15 min. The solid
was filtered off and an excess of sodium amide (NaNH2) was added to
the filtrate. After 30 min of stirring at room temperature, 15 mL of
water were slowly added. The product was extracted with AcOEt, the
organic layer was dried over MgSO4, filtered and evaporated. The
crude product was purified by column chromatography using AcOEt
as eluent. 0.500 g (93%) of amide 5 was obtained as an orange-red
4.2.6. 4-[4-(2-ferrocenyl-1-phenylbut-1-en-1-yl)anilino]-4-
oxobutyric acid, 7
solid in
a
Z/E isomer ratio: 60/40. mp: 95e96 ꢀC. 1H-NMR
0.99 (1.00 for E isomer, t,
(300 MHz, (CD3)2SO, ppm): Z isomer,
d
J ¼ 7.4 Hz, 3H: a), 1.42e1.67 (m, 4H: q, p), 2.00e2.13 (m, 2H: r), 2.16e
2.36 (m, 2H: o), 2.48 (q, J ¼ 7.4 Hz, 2H: b), 3.83 (3.77 for E, t, J ¼ 1.9 Hz,
2H:
a
), 4.11 (4.08 for E, t, J ¼ 1.9 Hz, 2H:
b), 4.12 (s, 5H: Cp), 6.72 (s,1H:
w’), 6.96 (7.04 for E, d, J ¼ 8.5 Hz, 2H: j), 7.21 (d, J ¼ 7.5 Hz, 2H: f), 7.20e
7.30 (m, 4H: f, w, h), 7.34 (t, J ¼ 7.5 Hz, 2H: g), 7.48 (7.55 for E, d,
J ¼ 8.5 Hz, 2H: k), 9.86 (9.89 for E, s, 1H: m). 13C-NMR (75 MHz,
(CD3)2SO, ppm): Z isomer,
d 15.4 (a), 24.9 (q), 25.0 (p), 27.1 (b), 35.0 (r),
36.3 (o), 68.1 ( ), 68.8 (a), 69.1 (Cp), 85.5 (i), 119.1 (k), 126.2 (h), 128.4
b
(129.1 for E, g), 128.8 (129.2 for E, f),129.5 (j),136.6 (c),137.0 (d), 137.6
(l), 139.1 (i), 144.4 (e), 171.1 (n), 174.2 (s). IR (KBr, ymax/cmꢁ1): 3433,
3294 (NeH stretch), 3097 (CAreH stretch), 2950, 2873 (CAlkeH
stretch), 1658 (NC]O stretch), 1600 (CAr]CAr stretch), 1519 (NeH
bend), 1404 (CeN stretch). MS (CI, m/z): 552 [MNH4]þ, 535 [MH]þ.
Anal. Calc. for C32H34FeN2O2$½ H2O (%): C, 70.72; H, 6.49; N, 5.15.
Found: C, 70.71; H, 6.48, N, 5.08. HPLC (RT, min): 3.77 (MeOH), 7.79
(MeOH/H2O, 90/10).
An excess of NaOH was added to a solution of 6 (0.51 mmol,
0.25 g) in MeOH at room temperature. After 15 min of stirring,
water was added and the mixture was slightly acidified with HCl.
The product was extracted with AcOEt, the organic layer was dried
over MgSO4, filtered and evaporated. The crude product was puri-
fied by column chromatography using a 1:1 mixture of hexane and
AcOEt. 0.25 g (96%) of 8 was obtained as an orange-red solid in a Z/E
isomer ratio ¼ 70/30. This product can also be obtained, but in low
yields, following the same protocol to synthesized succinimide 6.
However, the acid hydrolysis of bisamide 8 is also an alternative
way to produce more of 7. This hydrolysis can be performed directly
on the reaction medium or on bisamide itself. Thus, an excess of HCl
was added to a stirred solution of 8 in acetone/water. After 1 h of
reflux, carboxylic acid 7 and amine 1 were obtained. mp: 210e
4.2.5. N-[4-(2-ferrocenyl-1-phenylbut-1-en-1-yl)phenyl]
succinimide, 6
213 ꢀC. 1H-NMR (300 MHz, (CD3)2SO, ppm): Z isomer,
for E isomer, t, J ¼ 7.4 Hz, 3H: a), 2.41e2.60 (m, 6H: b, p o), 3.83 (3.78
), 4.13 (s,
d 0.99 (1.00
for E, t, J ¼ 1.9 Hz, 2H:
a
), 4.11 (4.08 for E, t, J ¼ 1.9 Hz, 2H:
b
5H: Cp), 6.96 (7.04 for E, d, J ¼ 8.5 Hz, 2H: j), 7.21 (d, J ¼ 7.5 Hz, 2H:
f), 7.24 (t, J ¼ 7.5 Hz, 1H: h), 7.34 (t, J ¼ 7.5 Hz, 2H: g), 7.48 (7.55 for E,
d, J ¼ 8.5 Hz, 2H: k), 9.94 (9.97 for E, s, 1H: m), 12.17 (s, 1H: x). 13C-
NMR (75 MHz, (CD3)2SO, ppm): Z isomer,
d
15.4 (a), 27.1 (b), 28.8
(p), 31.0 (o), 68.1 (b), 68.8 (a), 69.1 (Cp), 85.5 (i), 118.9 (k), 126.2 (h),

618
J.deJ. Cázares-Marinero et al. / Journal of Organometallic Chemistry 751 (2014) 610e619
128.4 (129.1 for E, g), 128.7 (129.2 for E, f), 129.5 (j), 136.6 (c), 137.0
(d), 137.5 (l), 139.1 (i), 144.3 (e), 170.0 (n), 173.8 (q). IR (KBr, ymax
filtrate was added to the freshly prepared solution of NH2OH in
MeOH. The resulting mixture was stirred at room temperature for
2 h. After that, water was added and the mixture was slightly
acidified with HCl. The product was extracted with AcOEt, the
organic layer was dried over MgSO4, filtered and evaporated. The
crude product was purified by column chromatography using
AcOEt as eluent. 0.185 g (30%) of 9 was obtained as an orange-red
solid in a Z/E isomer ratio ¼ 73/27. This compound can also be
obtained by the direct attack of hydroxylamine to the succinimide 6
as follows. A solution of succinimide 6 (1.02 mmol, 0.50 g) reacted
with an excess of basic NH2OH freshly prepared in MeOH as
described above at room temperature for 20 min. After that, water
was added and the mixture was slightly acidified with HCl. The
product was extracted with AcOEt, the organic layer was dried over
MgSO4, filtered and evaporated. The crude product was purified by
column chromatography using AcOEt as eluent. 0.100 g (19%) of
product 9 was obtained. mp: 200e202 ꢀC. 1H-NMR (300 MHz,
/
cmꢁ1): 3321 (NeH and OeH stretch), 3097 (CAreH stretch), 2966
(CAlkeH stretch), 1712 (OC ¼ O stretch), 1662 (NC]O stretch), 1601
(CAr]CAr stretch), 1531 (NeH bend), 1404 (CeN stretch), 1250 (CeO
stretch). MS (CI, m/z): 525 [MNH4]þ, 508 [MH]þ, 408 [FPBA-H]þ.
Anal. Calc. for C30H29FeNO3 (%): C, 71.01; H, 5.76; N, 2.76. Found: C,
69.91 H, 5.86; N, 2.75. HPLC (RT, min): 3.46 (MeOH), 5.98 (MeOH/
H2O, 90:10).
4.2.7. N1,N4-bis[4-(2-ferrocenyl-1-phenylbut-1-en-1-yl)phenyl]
succinamide, 8
(CD3)2SO, ppm): Z isomer,
a), 2.27 (t, J ¼ 7.0 Hz, 2H: p), 2.43e2.60 (m, 4H: b, o), 3.82 (3.77 for E,
), 4.12 (s, 5H:
d
0.99 (1.00 for E isomer, t, J ¼ 7.4 Hz, 3H:
t, J ¼ 1.9 Hz, 2H:
a
), 4.11 (4.08 for E, t, J ¼ 1.9 Hz, 2H:
b
Cp), 6.96 (7.04 for E, d, J ¼ 8.5 Hz, 2H: j), 7.21 (d, J ¼ 7.5 Hz, 2H: f),
7.24 (t, J ¼ 7.5 Hz, 1H: h), 7.34 (t, J ¼ 7.5 Hz, 2H: g), 7.48 (7.55 for E, d,
J ¼ 8.5 Hz, 2H: k), 8.72 (s, 1H: w), 9.95 (9.98 for E, s, 1H: m), 10.43 (s,
1H: x). 13C-NMR (75 MHz, (CD3)2SO, ppm): Z isomer,
d
15.4 (a), 27.1
(b), 27.4 (p), 31.5 (o), 68.1 (
b), 68.8 (
a
), 69.1 (Cp), 85.5 ( ), 118.9 (k),
i
126.2 (h), 128.4 (129.1 for E, g), 128.7 (129.2 for E, f), 129.5 (j), 136.6
(c), 137.0 (d), 137.6 (l), 139.1 (i), 144.3 (e), 168.3 (q), 170.1 (n). IR (KBr,
ymax/cmꢁ1): 3255 (NeH and OeH stretch), 3097 (CAreH stretch),
2966 (CAlkeH stretch), 1658 (NC]O stretch), 1600 (CAr]CAr
stretch), 1523 (NeH bend), 1404 (CeN stretch). MS (ESI, m/z): 521
[M ꢁ H]ꢁ. Anal. Calc. for C30H30FeN2O3$H2O (%): C, 66.67; H, 5.97; N,
5.18. Found: C, 66.17; H, 5.63; N, 5.22. HPLC (RT): 3.55 (MeOH), 7.07
(MeOH/H2O, 90:10).
Bisanilide 8 was identified as byproduct for 6 and 7 synthesis.
mp: 98e99 ꢀC. 1H-NMR (300 MHz, (CD3)2CO, ppm): major isomer
(78%),
J ¼ 7.4 Hz, 4H: b), 2.72 (2.73 for minor, s, 4H: o), 3.92 (3.87 for minor,
), 4.13 (s,
d
1.02 (1.04 for minor isomer, t, J ¼ 7.4 Hz, 6H: a), 2.60 (q,
t, J ¼ 1.9 Hz, 4H:
a
), 4.08 (4.06 for minor, t, J ¼ 1.9 Hz, 4H:
b
5H: Cp), 6.99 (7.08 for minor, d, J ¼ 8.5 Hz, 2H: j), 7.10-7.29 (m, 3H: f,
h), 7.34 (t, J ¼ 7.5 Hz, 2H: g), 7.55 (7.65 for minor, d, J ¼ 8.5 Hz, 2H: k),
9.24 (9.28 for minor, s, 1H: m). 13C-NMR (75 MHz, (CD3)2CO, ppm):
4.2.9. N1-[4-(2-ferrocenyl-1-phenylbut-1-en-1-yl)phenyl]
succinimide, 10
major isomer,
d 15.8 (a), 28.4 (b), 32.4 (o), 68.9 (b), 69.9 (Cp), 70.0
(a
), 87.2 ( ), 119.7 (k), 127.0 (h), 129.1 (g), 130.0 (f), 130.8 (j), 138.0 (c),
i
138.4 (d), 138.7 (l), 140.6 (i), 145.6 (e), 171.1 (n). MS (CI, m/z): 897
[MH]þ, 408 [FPBA-H]þ.
4.2.8. N1-[4-(2-ferrocenyl-1-phenylbut-1-en-1-yl)phenyl]-N4-
hydroxysuccinamide, 9
To a solution of 8 (0.59 mmol, 0.300 g) in 10 mL of anhydrous
THF, cooled to 0 ꢀC, ClCO2Et (3.0 mmol, 0.29 mL) and TEA
(3.4 mmol, 0.47 mL) were added and the mixture was stirred for
15 min. The solid was filtered off and an excess of sodium amide
(NaNH2) was added to the filtrate. After 30 min of stirring at room
temperature, 15 mL of water were slowly added. The product was
extracted with AcOEt, the organic layer was dried over MgSO4,
filtered and evaporated. The crude product was purified by column
chromatography using AcOEt as eluent. 0.102 g (36%) of amide 10
was obtained as an orange-red solid in a Z/E isomer ratio: 65/35.
mp: 235e236 ꢀC. 1H-NMR (300 MHz, (CD3)2SO, ppm): Z isomer,
A solution of NH2OH$HCl (10.0 mmol, 0.695 g) in 10 mL of
methanol (MeOH) was added to a stirred solution of potassium
hydroxide (KOH, 20.0 mmol,1.120 g) in 15 mL of MeOH at 0 ꢀC. After
it was stirred for 20 min, the precipitate was removed and the
filtrate was placed in a flask. In another flask, to a solution of 8
(1.18 mmol, 0.600 g) in 15 mL of anhydrous THF, cooled to 0 ꢀC,
ClCO2Et (5.7 mmol, 0.55 mL) and TEA (6.84 mmol, 0.95 mL) were
added and the mixture was stirred for 15 min and filtered. The
d
0.99 (1.00 for E isomer, t, J ¼ 7.4 Hz, 3H: a), 2.33e2.42 (m,
J ¼ 7.0 Hz, 2H: p), 2.48 (q, J ¼ 7.4 Hz, 2H: b), 2.46e2.60 (m, 2H: o),
3.82 (3.77 for E, t, J ¼ 1.9 Hz, 2H: ), 4.11 (4.08 for E, t, J ¼ 1.9 Hz, 2H:
a

J.deJ. Cázares-Marinero et al. / Journal of Organometallic Chemistry 751 (2014) 610e619
619
b
), 4.13 (s, 5H: Cp), 6.77 (s, 1H: w’), 6.96 (7.04 d, J ¼ 8.5 Hz, 2H: j),
FPBA
HDAC
4-(2-ferrocenyl-1-phenylbut-1-en-1-yl)aniline
histone deacetylase
7.21 (d, J ¼ 7.5 Hz, 2H: f), 7.24 (t, J ¼ 7.5 Hz, 1H: h), 7.31e7.36 (s, 1H:
w), 7.34 (t, J ¼ 7.5 Hz, 2H: g), 7.48 (7.55 for E, d, J ¼ 8.5 Hz, 2H: k),
9.91 (9.94 for E, s, 1H: m). 13C-NMR (75 MHz, (CD3)2SO, ppm): Z
isomer,
(Cp), 85.5 (
136.6 (c),137.0 (d),137.6 (l),139.0 (i),144.4 (e),170.5 (n),173.4 (q). IR
(KBr, ymax/cmꢁ1): 3433, 3282 (NeH stretch), 3093 (CAreH stretch),
2966, 2927, 2873 (CAlkeH stretch), 1654 (NC]O stretch), 1604
(CAr]CAr stretch), 1516 (NeH bend), 1404 (CeN stretch). MS (CI, m/
z): 524 [MNH4]þ, 507 [MH]þ, 408 [FPBA-H]þ. Anal. Calc. for
HDACi histone deacetylase inhibitor
HER2
JAHA
PSA
SAHA
TAM
TEA
human epidermal growth factor receptor 2
N1-ferrocenyl-N8-hydroxysuberamide
N1-phenylsuberamide
d
15.4 (a), 27.1 (b), 29.9 (p), 31.5 (o), 68.1 (
b), 68.8 (a), 69.1
i), 118.9 (k), 126.2 (h), 128.4 (129.1 g), 128.8 (f), 129.5 (j),
N1-hydroxy-N8-phenylsuberamide
tamoxifen
triethylamine
tetrahydrofuran
THF
C
30H30FeN2O2$3H2O (%): C, 64.29; H, 6.47; N, 5.00. Found: C, 64.79;
References
H, 6.07; N, 4.86. HPLC (RT, min): 3.59 (MeOH), 7.32 (MeOH/H2O,
[1] G. Jaouen, Bioorganometallics, John Wiley & Sons, Germany, 2006.
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The National Council of Science and Technology of Mexico
(CONACyT) is thanked for granting a PhD scholarship to JJCM and
the Agence Nationale de la Recherche (ANR 2010 BLAN 7061 blanc
“Mecaferrol”) is thanked for financial support.
Abbreviations
EGFR
epidermal growth factor receptor
FcTAM3 ferrocifen
FcTAM-PSA N1-[4-(2-ferrocenyl-1-phenylbut-1-en-1-yl)phenyl]
suberamide
FcTAM-SAHA N1-[4-(2-ferrocenyl-1-phenylbut-1-en-1-yl)
phenyl]-N8-hydroxysuberamide