Synthesis of N,N′-bis(5-arylidene-4-oxo-3,5-dihydro-4H-imidazol-2-yl) diamines bearing various linkers and biological evaluation as potential inhibitors of kinases

Article abstract of DOI:10.1016/j.ejmech.2012.08.044

The synthesis in 4 steps of new N,N′-bis(5-arylidene-4-oxo-3,5- dihydro-4H-imidazol-2-yl)diamines issued from various symmetric primary diamines as linkers was reported. The key step of our strategy has been the sulphur/nitrogen displacement of (5Z)-5-arylidene-2-ethylsulfanyl-3,5-dihydro- 4H-imidazol-4-ones 6 with respectively ethylenediamine 7a, piperazine 7b and N,N′-bis(3-aminopropyl)piperazine 7c using solvent-free reaction conditions under microwave irradiation with retention of configuration. These compounds were tested for their kinase inhibitory potencies toward four kinases (GSK-3α/β, DYRK1A, CLK1 and CLK3).

Full text of DOI:10.1016/j.ejmech.2012.08.044

European Journal of Medicinal Chemistry 58 (2012) 581e590
Contents lists available at SciVerse ScienceDirect
European Journal of Medicinal Chemistry
journal homepage: http://www.elsevier.com/locate/ejmech
Original article
Synthesis of N,N0-bis(5-arylidene-4-oxo-3,5-dihydro-4H-imidazol-2-yl)diamines
bearing various linkers and biological evaluation as potential inhibitors of kinases
,
Wacothon Karime Coulibaly a b, Ludovic Paquin a, Anoubilé Bénie b, Yves-Alain Bekro b, Emilie Durieu c,
,
Laurent Meijer d, Jean Pierre Bazureau a
*
a Université de Rennes 1, Institut des Sciences Chimiques de Rennes (ISCR), UMR CNRS 6226, groupe Ingénierie Chimique et Molécules pour le Vivant (ICMV), Bât. 10A,
Campus de Beaulieu, Avenue du Général Leclerc, CS 74205, 35042 Rennes Cedex, France
b Université d’Abobo-Adjamé, Laboratoire de Chimie Bioorganique et de Substances Naturelles (LCBSN), BP 802, Abidjan 02 (CO), Cote d’Ivoire
c Protein Phosphorylation and Human Disease Group, Station Biologique CNRS, Place G. Tessier, BP 74, 29682 Roscoff (F), France
d ManRos Therapeutics (From Sea to Pharmacy), Hôtel de Recherche, Centre de Perharidy, 29680 Roscoff (F), France
a r t i c l e i n f o
a b s t r a c t
The synthesis in 4 steps of new N,N0-bis(5-arylidene-4-oxo-3,5-dihydro-4H-imidazol-2-yl)diamines
issued from various symmetric primary diamines as linkers was reported. The key step of our strategy
has been the sulphur/nitrogen displacement of (5Z)-5-arylidene-2-ethylsulfanyl-3,5-dihydro-4H-imida-
zol-4-ones 6 with respectively ethylenediamine 7a, piperazine 7b and N,N0-bis(3-aminopropyl)pipera-
zine 7c using solvent-free reaction conditions under microwave irradiation with retention of
configuration. These compounds were tested for their kinase inhibitory potencies toward four kinases
Article history:
Received 4 May 2012
Received in revised form
29 August 2012
Accepted 30 August 2012
Available online 7 September 2012
(GSK-3
a
/b
, DYRK1A, CLK1 and CLK3).
Crown Copyright Ó 2012 Published by Elsevier Masson SAS. All rights reserved.
Keywords:
5-Arylidene-imidazolinone
Sulphur/nitrogen displacement
Diamino linker
N,N0-bis(5-arylidene-4-oxo-3,5-dihydro-4H-
imidazol-2-yl)diamine
Microwave irradiation
Solvent-free
Kinase inhibitors
1. Introduction
of 5, and Plasmodium vivax most morbidity additionally repre-
senting a reservoir of latent infections [3]. The infection stages of
the malaria parasite reside in the salivary glands of female
mosquito that bite humans for a blood meal. The mosquito injects
its saliva into the wound, then transferring approximatively 15e20
so-called sporozoites into the blood stream [4]. Anti-malarial
agents are classified by the stages of the malaria life cycle that
are targeted by the blood. Currently there are only limited safe
drugs for the treatment of the disease, however, reports of
emerging resistance against existing drugs warrant the introduc-
tion of new drugs. Recently, the re-emergence of malaria as a public
health problem demonstrates the urgent need for the discovery
and development of new anti-malarial drugs.
Traditionally, the chemotherapy of malaria involves killing of
the asexual parasites and providing supportive therapy to the host
to boots its immune system. In this context and prior to the 2nd
world war, quinine and its derivatives (pamaquine, chloroquine)
were used intensively. They were followed by proguanyl and
amodiaquine in the 1940s, followed by primaquine and pyri-
methamine (1950s), sulfadoxine (1960s) [5]. The use of medicinal
According to the World Heath Organisation (WHO), between
300 million and 500 million clinical case of malaria occur every
year [1]. Malaria is one of the most severe infectious diseases,
primarily affecting the world’s most disadvantaged populations.
This parasite infection is estimated to kill more than 1 million
people annually and possibly as many as 3 million, with most of the
deaths among children under age six living in undeveloped sub-
Saharian Africa [2]. Despite the presence of commercially avail-
able anti-malarial drugs, the disease is gaining ground as the
parasite’s resistance to drugs and the parasite-carrying mosquito’s
resistance to insecticides expand. Of the four typically recognized
Plasmodium species causing diseases in humans, which can be
transmitted by about 60 species of Anopheles mosquito, Plasmodium
falciparum causes most mortality, mainly in children below the age
* Corresponding author. Fax: þ33 (0)223 236 374.
E-mail address: jean-pierre.bazureau@univ-rennes1.fr (J.P. Bazureau).
0223-5234/$ e see front matter Crown Copyright Ó 2012 Published by Elsevier Masson SAS. All rights reserved.
http://dx.doi.org/10.1016/j.ejmech.2012.08.044

582
W.K. Coulibaly et al. / European Journal of Medicinal Chemistry 58 (2012) 581e590
plants such as the Chinese “sweet wormwood” Artemisia annua,
has a long tradition in the treatment of malaria [6] and identifi-
cation of the major active metabolite of this plant, artemisin, gave
rise the development of numerous anti-malarial drug derivatives,
such as artemether, artesunate and dihydroartemisin in the
1980s [7].
2. Chemistry
Concerning the strategy used, we envisaged to prepare a series
of novel N,N0-bis-(5-arylidene-4-oxo-3,5-dihydro-4H-imidazol-2-
yl)diamines from appropriate symmetric alkyldiamines as flexible
linkers with various 5-arylidene-2-ethylsulfanyl-3,5-dihydro-4H-
imidazoline-4-one partners by sulphur/nitrogen displacement [15]
as key step of the process. The overall strategy for the synthesis of
the symmetric derivatives 8e10 is outlined in Scheme 1.
Due to the intensive use of chloroquine (CQ) as a drug of choice
for treating malaria since the 1950s, the CQ-resistance appeared in
East-Asian countries and then, in most part of the world. Around
the world, the CQ-resistance induced several efforts of the
researchers to develop new anti-malarial drugs derived from 4-
aminoquinolines moieties connected by linkers of various lengths
and chemical nature. The interest of such bis-quinolines has been
explained by the fact of their steric bulk prevents them from fitting
into the substrate binding site of P. falciparum CQ-resistance
transporter (PfCRT). So, the role of bis-quinolines in malaria
chemotherapy has been extensively reviewed [8]. Piperaquine [9]
(Fig. 1) is the most advanced representative of this family and
was developed in 1960s; it has been extensively used in China. The
increasing spread of malaria together with the emergence of
resistance against conventional anti-malarial drugs has put enor-
mous pressure on the public health systems to introduce new
therapeutics. Unfortunately, the number of drug classes is very
restricted. Cocktails of anti-malarial drugs are now recommended
to prevent chemoresistance. This emphasizes that alternative drugs
with a novel mechanism of action need to be urgently developed.
Pentamidine (Fig. 1) is a diamidine, which has a long history as
antiprotozoal agent against trypanosomiasis and leishmaniasis
since 1930s. Recently, it was proposed that diamidines act against
Plasmodium species through the ferri-protophorphyrin binding and
the inhibition of mitochondrial functions [10]. The curative effect of
N-alkylamidine [11], as M34, inhibits the P. falciparum parasite’s
multiplication in low nanomolar range (IC50 ¼ 0.3 nM) and was
demonstrated in an animal model. This agent was able to inhibit
plasmodial phosphatidylcholine de novo biosynthesis in infected
erythrocytes [12]. The strategy was then confirmed with the bis-
thiazolium salt [13] (T3, Fig. 1) active against rodent and non-
human primate malaria.
The synthesis started with the solution preparation of N-alkyl
thiohydantoines 1(a,b) from methyl glycinate hydrochloride and
commercial isothiocyanates 1(a,b) (1a: R1 ¼ Me, 1b: R1 ¼ Bu). In
the second step for the Knoevenagel products 5(aeh), an equi-
molecular mixture of the starting hydantoine 2 and arylaldimine 4
was heated at 80 ꢀC under microwave (mu, in the ExplorerÒ 24
CEM microwave reactor) using solventless reaction conditions for
a reaction time of 30 min. The arylaldimines 4(aee) were prepared
in good yields (93e99%, Table 1) according to a solvent-free
microwave protocol developed in our laboratory [16]. In all
cases, compounds 5(aeh) were obtained in a stereospecific way
and the geometric double bond was attributed as being Z by the
shielding effect of the carbonyl group C-4 on the olefinic proton
H-5 (dH-5 w6.6 ppm) in the 1H NMR spectra. Accessibility to the
S-ethyl compounds 6(aef) involved the solution reaction of
5-arylidene thiohydantoines 5 with 1.5 equiv of ethyliodide in the
presence of 0.5 equiv of potassium carbonate. After 24 h at 60 ꢀC
and work-up (elimination of the salts and the solvent under
vacuum), all the 5-arylidene-2-ethylsulfanyl-3,5-dihydro-4H-imi-
dazol-4-one 6(aef) were easily purified by recrystallization with
a mixture of pentane/ethanol (1:1). As seen from the results in
Table 1, it can be observed that the alkylation’s step gave yields
ranging from 54 to 88%. The structure assignment of the
compounds 6(aef) is based on spectroscopic data (1H, 13C NMR,
HRMS) and the diversity on these compounds has been introduced
at the N-2 position and at the C-5 position by Knoevenagel
condensation. It should be noted that this alkylation step gave
regioselective S-alkylation with retention of the (5Z)-stereo-
chemistry (dH-5 ¼ 6.81e6.92 ppm).
Regarding the anti-malarial activity issued from N-alkylamidine,
we decided to explore the synthesis of an expanded series of N,N0-
bis-(5-arylidene-4-oxo-3,5-dihydro-4H-imidazol-2-yl)diamines as
potential candidates in the anti-malarial chemotherapy. Thus,
taking into account our experience in the field of the synthesis of
new bioactive heterocyclic compounds based on imidazoline-4-one
heterocyclic core [14], we used the 2-amino-5-arylidene-imidazo-
line-4-one moiety linked through various symmetric diamino
linkers (Fig. 2). Thus, an investigation into the potential of these
compounds for this purpose was investigated and also their bio-
logical evaluation as protein kinase inhibitors. The 518 protein
kinases of the human kinome constitute a wide family of disease-
relevant targets for the identification and optimization of poten-
tial therapeutic agents.
With the 5-arylidene-3,5-dihydro-4H-imidazol-4-ones 6(aef)
in hand, activated with an alkylthio group in position C-2 for
a subsequent sulphur/nitrogen displacement from a primary
diamine, we continued to study the influence of microwave
irradiation in order to obtain a large number of N,N0-bis(5-
arylidene-imidazolinone) compounds suitable for the biological
screening. The main benefits of performing the reaction under
microwave conditions are the significant rate-enhancements and
the better product yields that can be observed. It is clear that the
use of microwave irradiation technology to rapid synthesis of
potential molecules is a useful tool for medicinal community [17].
In this context we examined the influence of microwave irradi-
ation on
a neat mixture of 5-arylidene-2-ethylsulfanyl-3,5-
dihydro-4H-imidazol-4-one 6 and diamine reagent 7. For this
N
N
H2N
HN
NH2
NH
O
O
N
N
N
N
HN
H2N
NH
NH2
10
M34
IC50 = 0.3 nM
Cl
Cl
N
piperaquine
pentamidine
2 Br
S
S
T3
IC50 = 2.2 nM
HO
OH
N
10
Fig. 1. Anti-plasmodial compounds.

W.K. Coulibaly et al. / European Journal of Medicinal Chemistry 58 (2012) 581e590
583
privileged 2-amino-
imidazolinone scaffold
R2 , R3
R2 , R3
R3 ,R2
R3 ,R2
H
N
H
N
S
N
S
N
N
N
linker
linker
H2N
NH2
N
N
N
N
R1
R1
R1
R1
O
O
O
O
diamino linker
2-thioethyl-5-arylidene-
imidazoline-4-one
lipophilicity and variable
alkyl chain lenght
Fig. 2. Retrosynthetic strategy toward N,N0-bis-(5-arylidene-4-oxo-3,5-dihydro-4H-imidazol-2-yl)diamines.
study, the primary diamines employed were, ethylenediamine 7a,
piperazine 7b and N,N0-bis(3-aminopropyl)piperazine 7c. Reac-
tion optimization for the preparation of compounds 8 derived
from ethylenediamine 7a or compounds 9 issued from piperazine
7b or compounds 10 obtained from the N,N0-disubstituted
piperazine 7c consisted in varying the reaction temperature
(from 60 to 160 ꢀC), the reaction concentration (ratio 7/6 from 0.5
to 2), the power for microwave irradiation (100, 150 and 200 W)
and the reaction time (from 15 to 60 min). After performing the
test reactions, the experiments revealed that the optimal micro-
wave reaction conditions were obtained when the optimal ratio
6/7 was obtained with 1.5 equiv of ethylenediamine 7a, 1 equiv of
piperazine 7b and 0.5 equiv of 7c. For the other parameters, the
reaction mixture was irradiated at 100e160 ꢀC (200 W) during
a reaction time of 20e45 min. It is noteworthy that for safety
temperature was maintained at the selected reaction
temperature.
As seen from the results of Table 2, the reaction time is depen-
dent upon the nature of the diamino reagent 7 and also the
substituents on the 5-arylidene-3,5-dihydro-4H-imidazolin-4-one
6 (R1, R2, R3 or R2eR3). For example, access to compound 8a from
5b (R1 ¼ Me, R2 ¼ H, R3 ¼ 4-MeO) and 7a requires a reaction time of
30 min but for 10b from 5b and 7c, it was necessary to heat at
160 ꢀC with the same reaction time (30 min). In fact, the versatility
of this sulphur/nitrogen displacement [18] was demonstrated
through the preparation of a small library of 17 new N,N0-bis(5-
arylidene-4-oxo-3,5-dihydro-4H-imidazol-2-yl)diamines 8(aed),
9(aef) and 10(aeg) with various linkers in yields ranging from 9
to 72%. The structures of all compounds 8, 9 and 10 were
substantiated by 1H, 13C and HRMS analyses and only the thermo-
dynamically more stable Z-isomers were obtained.
reasons,
a
3-min heating ramp was performed before the
H
N
S
CO2Me
i
iii
N
O
R2, R3
R1-N=C=S
R2, R3
N
R1
NH2, HCl
1a: R1 = Me
O
2(a,b)
3a: R2, R3 = H
4a: R2, R3 = H
1b: R1 = n-Bu
3b: R2 = H, R3 = 4-OH
3c: R2 = H, R3 = 4-MeO
3d: R2, R3 = 3,4-OCH2O
4b: R2 = H, R3 = 4-MeO
4c: R2, R3 = 3,4-OCH2O
4d: R2 = H, R3 = BzO
4e: R2 = H, R3 = n-BuO
iv
ii
3e: R2 = H, R3 = BzO
3f: R2 = H, R3 = n-BuO
R2, R3
R2, R3
H
N
EtS
N
S
vi
v
NH2
HN
NH
or
or
H2N
N
N
R1
R1
O
O
7a
7b
6(a-f): R1 = Me, Bu
5(a-g): R1 = Me, Bu
R2 = H
R2 = H
R3 = H, 4-MeO, 4-n-BuO
R3 = H, 4-MeO, 4-n-BuO
H2N
N
N
NH2
R2, R3 = 3,4-OCH2O
R2, R3 = 3,4-OCH2O
7c
R2 ,R3
R2, R3
R2 ,R3
R2, R3
H
N
H
N
3
R1
H
N
H
N
N
3
N
N
N
N
N
2
N
N
N
N
R1
R1
R1
O
or
O
O
O
R2 ,R3
R2, R3
10(a-g): R1 = Me, Bu
8(a-d): R1 = Me, Bu
R2 = H
or
R2 = H
R3 = H, 4-MeO, 4-n-BuO
R3 = H, 4-MeO, 4-n-BuO
R2, R3 = 3,4-OCH2O
R2, R3 = 3,4-OCH2O
9(a-f): R1 = Me, Bu
N
N
N
N
R2 = H
N
N
R3 = H, 4-MeO, 4-n-BuO
O
O
R1
R1
R2, R3 = 3,4-OCH2O
Scheme 1. Reagents and reaction conditions. (i) 1 1 equiv., Et3N, Et2O, reflux, oil bath, 18 hrs. (ii) K2CO3 1.5 equiv., RX 1.05 equiv., MeCN, reflux, 96 hrs. (iii) Pr-NH2 2 equiv., 60ꢀC,
30 min., mu (ExplorerÒ 24CEM microwave reactor). (iv) 4 1 equiv., 80ꢀC, 30 min., mu , 200 W (v) EtI 1.5 equiv., K2CO3 0.5 equiv., MeCN, 60ꢀC, oil bath, 24 hrs. (vi) ethylenediamine 7a
1-1.5 equiv. or piperazine 7b 1 equiv. or N,N0-bis(3-aminopropoyl)piperazine 7c 0.5 equiv., 100-160ꢀC, 20-45 min., mu, 300 W.

584
W.K. Coulibaly et al. / European Journal of Medicinal Chemistry 58 (2012) 581e590
Table 1
Table 3
Results for the preparation of thiohydantoines 2(a,b), aldehydes 3(e,f), arylaldimines
4(aee), 5-arylidene thiohydantoines 5(aeh) and 5-arylidene-2-ethylsulfanyl-3,5-
dihydro-4H-imidazoline-4-ones 6(aef).
Kinase inhibitiona values (IC50 in
mM) for compounds 8, 9 and 10.
Compound R1
R2 R3
4-MeO
Me 3,4-OCH2O
GSK-3
a
/b
DYRK-1A CLK1 CLK3
8a
8b
9a
9b
9c
9d
10a
10b
10c
10d
10e
10f
10g
Me
H
>10
>10
>10
>10
>10
>10
>10
>10
>10
>10
5.4
>10
>10
>10
>10
7.6
1.4
e
Compound
R1
R2
R3
Yielda (%)
e
2a
2b
3e
3f
Me
Bu
e
e
e
95
96
92
70
92
99
93
93
99
86
95
77
24
66
67
75
21
54
72
70
88
78
Me
Me
Me
Me
H
H
H
H
4-C6H5CH2O >10
4-BuO
H
>10
0.68
4
>10
>10
ꢁ10
0.61
4.1
e
e
e
>10
>10
>10
>10
e
H
H
H
H
H
H
4-C6H5CH2O
4-BuO
H
4-MeO
4-C6H5CH2O
4-BuO
e
e
4-MeO
>10
>10
>10
1.5
6.7
>10
>10
>10
4a
4b
4c
4d
4e
5a
5b
5c
5d
5e
5f
5g
6a
6b
6c
6d
6e
6f
e
Me 3,4-OCH2O
e
Me
Bu
Me
Me
Me
H
H
H
H
H
4-C6H5CH2O >10
4-C6H5CH2O 2.7
4-BuO
H
4-MeO
e
e
>10
>10
>10
>10
e
3,4-OCH2O
H
H
3,4-OCH2O
H
H
H
3,4-OCH2O
H
H
>10
>10
>10
Me
Me
Me
Me
Me
Bu
Bu
Me
Me
Me
Me
Me
Bu
H
4-MeO
Me 3,4-OCH2O
a
Kinase inhibition experiments were carried out as described previously
4-BuO
4-C6H5CH2O
4-MeO
[14ae23].
revealed that none of the prepared compounds 8, 9 and 10 was
active (IC50 > 100 M).
H
4-MeO
m
3,4-OCH2O
Protein kinases are the enzymes, which catalyze protein phos-
phorylation, a keycellular regulatory mechanism that is deregulated
in human diseases. Consequently, protein kinases represent inter-
esting targets for the pharmaceutical industry in its search for new
therapeutic agents. As an initial effort to investigate their in vitro
bioactivity, compounds 8, 9 and 10 were tested against four protein
H
H
H
4-C6H5CH2O
4-BuO
4-C6H5CH2O
a
Isolated yields.
kinases as GSK-3a/b (glycogen synthase kinase 3a/b), DYRK-1A
(dual-specificity, tyrosine phosphorylation activated kinase 1A)
3. Biology
[22], CLK1 and CLK3 (cdc2-like kinases). All assays were run in the
Chloroquinine (CQ) and the other anti-malarial drugs are
believed to act within the malaria food vacuole by binding heme
and thereby converting free heme, a toxic compound for the host
cell and the malarial parasite, into hemozoin [19] which is the non-
toxic malarial pigment. Current reports indicate that this chemical
transformation can be readily used for anti-malarial screening.
Egan et al. [20] reported that, ferriprotophorphyrin IX chloride
under acidic condition (pH 5.0) similar to that found in the lyso-
presence of 15
mM ATP and appropriate protein substrates GS-1
(YRRAAVPPSPSLSRHSSPHQSpEDEE) peptide for GSK-3a/b
[23], RS
peptide (GRSRSRSRSRSR) for CLK1 and CLK3, Wooltide (KKISGRL-
SPIMTEQ) for DYRK-1A. IC50 values were determined from dosee
response curves and are provided in Table 3.
Considering the CLK1 kinase, the best inhibitory potencies were
sub-micromolar inhibition for compounds 9b (IC50 ¼ 0.68
mM) and
10c (IC50 ¼ 0.61
m
M). These derivatives are substituted either by
somal vacuole of P. falciparum, evolved to yield a precipitate of b-
a (4-methoxyphenyl)methylene group or a (benzo [1,3]dioxol-5-yl)
methylene group on the C-5 position of the imidazolinone moiety
grafted to a piperazinyl or a (3-aminopropyl)piperazinyl linker. The
other compounds (8a, 8b, 9c and 10d) were mildlyactive toward this
kinase with IC50 values in the micromolar range ranging from 1.4
hematin (the synthetic form of hemozoin). In the presence of some
chemicals (quinine, chloroquine, amodiaquin) this reaction can be
inhibited and constituted a simple test enabling to identify
potential anti-P. falciparum agents [21]. Investigation of the anti-
plasmodial activity according to the in vitro b-hematin formation
(8b) to 7.6
micromolar inhibition potencies toward GSK-3
M). Regarding these
mM (8a). It is noteworthy that compound 10c has shown
a
/b
(IC50 ¼ 2.7 M),
m
DYRK-1A (IC50 ¼ 5.4
m
M) and CLK3 (IC50 ¼ 1.5
m
Table 2
Results for the preparation of N,N0-bis-(5-arylidene-4-oxo-3,5-dihydro-4H-imida-
zol-2-yl)diamines 8(aee), 9(aeg) and 10(aeg) issued from ethylenediamine 7a,
piperazine 7b and 1,4-bis(3-aminopropyl)piperazine 7c.
results, these new series of N,N0-bis(5-arylidene-imidazolinone)
appended on ethylenediamine, piperazine or N,N0-bis(3-
aminopropyl)piperazine as linkers could be particularly inter-
esting in the development of new inhibitors of CLK1 kinase. Further
biological investigations are underway.
Compound R1 R2 R3
Reaction temperature Reaction
Yielda
(ꢀC)
time (min) (%)
8a
8b
8c
8d
9a
9b
9c
9d
Me
H
4-MeO
120
120
30
30
30
20
30
35
45
30
30
30
30
30
30
30
30
30
30
20
25
11
10
47
72
22
62
15
26
22
32
36
9
Me 3,4-OCH2O
4. Conclusion
Me
Me
Me
Me
H
H
H
H
4-C6H5CH2O 120
4-BuO
H
100
160
160
140
In summary, new N,N0-bis(5-arylidene-4-oxo-3,5-dihydro-4H-
imidazol-2-yl)diamines 8, 9 and 10 with two diversity points have
been prepared according to a solvent-free microwave irradiation
protocol in the last key step by sulphur/nitrogen displacement. To
our knowledge, this approach for this new family of symmetric
N,N0-disubstituted diamines bearing 5-arylidene-imidazolinone
moiety as new model of diamidine has never been reported and
may be a complement to those existing in literature. The interesting
inhibition of compounds 9b and 10c toward the CLK1 kinase, which
is known to be involved in Alzheimer’s disease [14a] as key regu-
lator of pre-mRNA splicing, lead us to expand our effort in the
synthesis of new derivatives as new potential inhibitors of this
4-MeO
Me 3,4-OCH2O
Me
Bu
Me
Me
Me
Me 3,4-OCH2O
Bu 3,4-OCH2O
Me
Bu
H
H
H
H
H
4-C6H5CH2O 160
4-C6H5CH2O 160
4-BuO
H
9e
9f
160
150
160
160
150
10a
10b
10c
10d
10e
10f
10g
4-MeO
H
H
H
4-C6H5CH2O 160
4-C6H5CH2O 160
4-BuO
24
16
21
Me
140
a
Isolated yields.

W.K. Coulibaly et al. / European Journal of Medicinal Chemistry 58 (2012) 581e590
585
kinase. This work should enable further biological evaluations,
analogs through the synthesis process described here, and studies
of the structureeactivity relationship (SAR). Unfortunately, none of
the compounds 8, 9 and 10 showed inhibition activity as potential
Ar); 115.24 (C-2); 127.81 (C-3); 128.04 (C-1); 128.47 (C-30); 136.26
(C-20); 163.24 (C-10); 191.25 (C]O). HRMS, m/z: 213.0915 found
(calculated for C14H13O2 [M þ H]þ. requires 213.0916).
anti-P. falciparum agents using the inhibition assay of
formation. But the studies on kinase inhibitory potencies are on
going in our laboratory.
b
-hematin
5.1.1.2. 4-Butyloxybenzaldehyde (3f). The 4-butyloxybenzaldehyde
3f was prepared from 4-hydroxybenzaldehyde 3b (3 g, 24.6 mmol),
potassium carbonate (1.57 g, 15.9 mmol, 1.5 equiv) and potassium
iodide (4.08 g, 25.83 mmol, 1.05 equiv) in dry acetonitrile (20 ml),
a solution of bromobutane (2.77 ml, 25.83 mmol, 1.05 equiv) in
acetonitrile (10 ml) according tothe procedure used for the synthesis
5. Experimental section
5.1. Chemistry
of 4-benzyloxybenzaldehyde 3e. Yield: 70%. 1H NMR (DMSO-d6)
d:
0.92 (t, J ¼ 7.4 Hz; 3H, CH3CH2CH2CH2O); 1.41 (sext, J ¼ 2.1 Hz, 2H,
CH3CH2CH2CH2O); 1.71 (qint, J ¼ 2.8 Hz, 2H; CH3CH2CH2CH2O); 4.06
(t, J ¼ 6.5 Hz, 2H; CH3CH2CH2CH2O); 7.08 (d, J ¼ 8.7 Hz; 2H, H-3, Ar);
5.1.1. General remarks
Melting points were determined on a Kofler melting point
apparatus and were uncorrected. Thin-layer chromatography (TLC)
was accomplished on 0.2-mm precoated plates of silica gel 60 F-254
(Merck). Visualization was made with ultraviolet light (254 and
365 nm) or with a fluorescence indicator. 1H NMR spectra were
recorded on BRUKER AC 300P (300 MHz) spectrometer, 13C NMR
spectra on BRUKER AC 300P (75 MHz) spectrometer. Chemical shifts
are expressed in parts per million downfield from tetramethylsilane
as an internal standard. Data are given in the followingorder: d value,
multiplicity (s, singlet; d, doublet; t, triplet; q, quartet; m, multiplet;
br, broad), number of protons, coupling constants J is given in Hertz.
The mass spectra (HRMS) were taken respectively on an MS/MS
ZABSpec Tof Micromass (EBE TOF geometry) at an ionizing potential
of 8 eV and on a VARIAN MAT 311 at an ionizing potential of 70 eV in
the Centre Régional de Mesures Physiques de l’Ouest (CRMPO, Ren-
nes). Reactions under microwave irradiations were realized in the
ExplorerÒ 24 CEM microwave reactor (CEM France) using borosili-
cate glass vials of 10 ml equipped with snap caps (at the end of the
irradiation, cooling reaction was realized by compressed air). The
microwave instrument consists of a continuous focused microwave
power output from 0 to 300 W for the ExplorerÒ 24 CEM apparatus.
All the experiments were performed using stirring option. The target
temperature was reached with a ramp of 3 min and the chosen
microwave power stay constant to hold the mixture at this temper-
ature. The reaction temperature is monitored using calibrated
infrared sensor and the reaction time included the ramp period. The
microwave irradiation parameters (power and temperature) were
monitored by the ChemDriver software package for the ExplorerÒ 24
CEM apparatus. Solvents were evaporated with a BUCHI rotary
evaporator. All reagents and solvents were purchased from Acros,
Aldrich Chimie, and Fluka France and were used without further
purification. The starting thiohydantoines 2(a,b) and aldimines 4(ae
e) were synthesized according to our previous method [16].
7.83 (d, J ¼ 8.8 Hz; 2H, H-2, Ar); 9.85 (s, CHO). 13C NMR (DMSO-d6)
d:
13.51 (CH3(CH2)4O; 18.58 (CH3CH2CH2CH2O); 30.47 (CH3CH2-
CH2CH2O); 67.64 (CH3CH2CH2CH2O); 114.74 (C-2); 129.44 (C-4);
131.7 (C-3); 163.64 (C-1); 191.04 (C]O). HRMS, m/z: 179.1070 found
(calculated for C11H15O2 [M þ H]þ. requires 179.1072).
5.1.2. Standard procedure for the synthesis of 5-arylidene-2-thioxo-
imidazoline-4-one 5(aeg) under microwave irradiation
A mixture of N-methyl thiohydantoine 2a (0.5 g, 3.84 mmol) or N-
butyl thiohydantoine 2b (0.4 g, 1.83 mmol) and arylaldimine 4
(3.84 mmol for 2a or 1.83 mmol for 2b) was placed in a borosilicate
glass vial (10 ml) with a TeflonÒ magnetic stir bar and sealed with
a snap cap. The glass tube was then introduced into an ExplorerÒ 24
CEM microwave cavity (P ¼ 300 W). The stirred mixture was irra-
diated at 80 ꢀC (with a power of 200 W) for 30 min. After microwave
dielectric heating, the crude reaction mixture was allowed to cool
down to room temperature and was extracted with methylene
chloride (3 ꢃ 5 ml). The combined organic phases were dried over
MgSO4, filtered and the volatile solvent was eliminated in a rotary
evaporator under reduced pressure. The desired compound 5 was
purified by recrystallization from a mixture of pentane/chloroforme
(1:1). The precipitated product 5 was filtered and furtherdriedunder
high vacuum (10ꢂ2 Torr) for 1 h, which gave thedesired the N-methyl
or N-butyl-2-thioxo-5-arylidene-imidazoline-4-one 5 as a powder.
The compound 5 was characterized by 1H, 13C NMR and HRMS.
5.1.2.1. (5Z)-5-Benzylidene-3-methyl-2-thioxo-imidazolidin-4-one
(5a). Yield ¼ 86%. Brown powder. Mp ¼ 206e208 ꢀC. 1H NMR
(DMSO-d6)
d
¼ 3.19 (s, 3H, NCH3); 6.60 (s, 1H; ]CH); 7.40 (d, 2H,
J ¼ 7.3 Hz, H-20, Ar); 7.77 (dd, 3H, J ¼ 2 Hz, H-30, H-40, Ar); 11.22 (br s,
1H, NH). 13C NMR (DMSO-d6)
128.74 (C-2); 129.24 (C-4); 130.24 (C-3); 132.41 (C-1); 164.36 (C]S,
C-2); 179.26 (C]O, C-4). HRMS, m/z ¼ 218.0515 found (calculated
for C11H10N2OS, Mþ requires 218.0514).
d
¼ 27.21 (NCH3); 112.47 (C]CH);
5.1.1.1. 4-Benzyloxybenzaldehyde (3e). In
round-bottomed flask provided with
a
50 ml two-necked
a
magnetic stirrer and
condenser, a mixture of 4-hydroxybenzaldehyde 3b (3 g, 24.6 mmol)
and potassium carbonate (1.57 g, 15.9 mmol, 1.5 equiv) in dry
acetonitrile (20 ml) was stirred at room temperature for 30 min. To
this suspension, a solution of benzylbromide (3.08 ml, 25.83 mmol,
1.05 equiv) in 10 ml of acetonirile was added dropwise during
30 min. The resulting mixture was heated at 81 ꢀC over a period of
96 h under vigorous magnetic stirring. Then, the reaction was
allowed to cool down to room temperature and the insoluble salt
(KBr) was filtered off and the filtrate was concentrated in a rotary
evaporator under reduced pressure. The crude residue was dried
under vacuum (10ꢂ2 Torr) for 1 h. The 4-benzyloxybenzaldehyde 3e
(92% yield) was used without further purification. 1H NMR (DMSO-
5.1.2.2. (5Z)-5(4-Methoxybenzylidene)-3-methyl-2-thioxo-imidazoli-
din-4-one (5b). Yield ¼ 95%. Brown powder. Mp ¼ 170e172 ꢀC. 1H
NMR (DMSO-d6)
d
¼ 3.18 (s, 3H, NCH3); 3.81 (s, 3H, OCH3); 6.60 (s,
1H, ]CH); 6.97 (d, 2H, J ¼ 8.5 Hz, H-20, Ar); 7.75 (d, 2H, J ¼ 8.5 Hz,
H-30, Ar); 11.32 (br s, 1H, NH). 13C NMR (DMSO-d6)
d
¼ 27.18 (NCH3);
55.33 (OCH3); 113.28 (]CH); 114.36 (C-20, Ar); 124.31 (C-10, Ar);
124.78 (C], C-5); 132.28 (C-30, Ar); 160.34 (C]S, C-2); 164.14 (C-40,
Ar); 178.45 (C]O, C-4). HRMS, m/z ¼ 248.0617 found (calculated
for C12H12N2O2S, Mþ requires 248.0619).
5.1.2.3. (5Z)-5-(Benzo[1,3]dioxol-5-yl)methylene-3-methyl-2-thioxo-
imidazolidin-4-one (5c). Yield ¼ 75%. Yellow powder. Mp ¼ 118e
d6)
d
: 5.22(s, 2H, AreCH2eOeAr); 7.18 (d, 2H, J ¼ 8.1 Hz, H-3, Ar);7.30
120 ꢀC. 1H NMR (DMSO-d6)
d
¼ 3.18 (s, 3H, NCH3); 6.09 (s, 2H,
(d, 2H, J ¼ 4.3 Hz, H-20); 7.35 (q, 1H, J ¼ 2.5 Hz, H-40); 7.42 (t, 2H,
OCH2O); 6.54 (s,1H, ]CH); 6.96 (d,1H, J ¼ 8 Hz, H-50, Ar); 7.27 (d,1H,
J ¼ 1.5 Hz, H-30); 7.47 (d, 2H, J ¼ 1.6 Hz, H-20); 7.85 (dd, 2H, J ¼ 2.6 Hz,
J ¼ 8 Hz, H-60, Ar); 7.45 (s,1H, H-20, Ar); 12.22 (br s,1H, NH).13C NMR
H-3, Ar); 9.86 (s, 1H, CHO). 13C NMR (DMSO-d6)
d: 69.91 (AreCH2e
(DMSO-d6)
d
¼ 27.61 (NCH3); 102.10 (OCH2O); 109.10 (C-50, Ar);

586
W.K. Coulibaly et al. / European Journal of Medicinal Chemistry 58 (2012) 581e590
109.81 (C-20, Ar); 113.72 (]CH); 125.13 (C], C-5); 126.9 (C-60, Ar);
126.91 (C-10, Ar); 148.42 (C-30, C-40, Ar); 149.01 (C-30, C-40, Ar);
164.61 (C]O, C-4); 179.02 (C]S, C-2). HRMS, m/z ¼ 262.0409 found
(calculated for C12H10N2O3S, Mþ requires 262.0412).
thiohydantoine 5 (6 mmol), commercial potassium carbonate
(0.42 g, 3.02 mmol, 0.5 equiv) and ethyliodide (580 l, 7.25 mmol,
m
1.5 equiv) in dry acetonitrile (16 ml) was heated in a thermostated
oil bath at 60 ꢀC during 24 h under vigorous magnetic stirring. After
cooling down to room temperature, the reaction mixture was
concentrated in a rotary evaporator under reduced pressure. To
the crude residue was added methylene chloride (20 ml) and the
insoluble salt was filtered off. The volatile solvent of the filtrate
was eliminated under reduced pressure in a rotary evaporator.
The crude product 6 was recrystallized from a mixture of pentane/
ethanol (1:1) and further dried under high vacuum (10ꢂ2 Torr)
for 1 h, which gave the desired 5-arylidene-2-ethylthio-imidazo-
line-4-one 6 as a powder and was characterized by 1H, 13C and
HRMS.
5.1.2.4. (5Z)-5(4-Butyloxybenzylidene)-3-methyl-2-thioxo-imidazoli-
din-4-one (5d). Yield ¼ 24%. Yellow powder. Mp ¼ 142e144 ꢀC. 1H
NMR (DMSO-d6)
d
¼ 0.92 (t, 3H, J ¼ 7.3 Hz, CH3CH2CH2CH2O); 1.44
(sext, 2H, J ¼ 7.5 Hz, CH3CH2CH2CH2O); 1.69 (quint, 2H, J ¼ 7.5 Hz,
CH3CH2CH2CH2O); 3.18 (s, CH3N); 4.01 (t, 2H,
J
¼
6.4 Hz,
CH3CH2CH2CH2O); 6.58 (s, 1H, ]CH); 6.97 (d, 2H, J ¼ 8.7 Hz, H-20,
Ar); 7.73 (d, 2H, J ¼ 8.6 Hz, H-30, Ar); 12.23 (br s, 1H; NH). 13C NMR
(DMSO-d6)
d
¼ 13.63 (CH3CH2CH2CH2O); 18.65 (CH3CH2CH2CH2O);
27.16 (CH3CH2CH2CH2O); 30.60 (CH3N); 67.32 (CH3CH2CH2CH2O);
113.33 (]CH); 114.76 (C-20, Ar); 124.31 (C-40, Ar); 124.64 (C-10, Ar);
132.28 (C-30, Ar); 159.80 (C], C-5); 164.15 (C]S, C-2); 178.41 (C]O,
C-4). HRMS, m/z ¼ 290.1085 found (calculated for C15H18N2O2S, Mþ
requires 290.1089).
5.1.3.1. (5Z)-5-Benzylidene-2-ethylsulfanyl-3-methyl-3,5-dihydro-
4H-imidazol-4-one (6a). Yield ¼ 21%. Yellow powder. Mp ¼ 108e
110 ꢀC. 1H NMR (CDCl3)
d
¼ 1.46 (t, 3H, J ¼ 7.4 Hz, SCH2CH3);
3.09 (s, 3H, NCH3); 3.30 (q, 2H, J ¼ 8.1 Hz, SCH2CH3); 6.87 (s, 1H;
5.1.2.5. (5Z)-3-Methyl-5(4-phenylmethyloxybenzylidene)-2-thioxo-
]CH); 7.28e7.36 (m, 4H, J ¼ 5.3 Hz, H-30-H-40, Ar); 8.08 (dd, 2H,
imidazolidin-4-one (5e). Yield ¼ 66%. Yellow powder. Mp > 260 ꢀC.
J ¼ 1.6 Hz, H-20, Ar). 13C NMR (CDCl3)
d
¼ 14.32 (CH3CH2S); 25.21
1H NMR (DMSO-d6)
d
¼ 3.18 (s, 3H, NCH3); 5.17 (s, 2H, PhCH2O); 6.60
(NCH3); 26.52 (CH3CH2S); 123.51 (]CH); 128.61 (C-30, Ar); 129.65
(C-40, Ar); 131.84 (C-20, Ar); 134.55 (C-10, Ar); 138.54 (C], C-5);
164.91 (C]N, C-2); 169.92 (C]O, C-4). HRMS, m/z ¼ 248.0875
found (calculated for C13H14N2OS, Mþ requires 246.0872).
(s, 1H, ]CH); 7.08 (d, 2H, J ¼ 8.7 Hz, H-20, Ar); 7.43e7.47 (m, 5H,
J ¼ 5.3, 9.1 Hz, H-200, H-300, H-400, Ar); 7.75 (d, 2H, J ¼ 8.7 Hz, H-30, Ar);
12.26 (br s, 1H, NH). 13C NMR (DMSO-d6)
d
¼ 27.18 (CH3N); 69.32
(PhCH2O); 113.15 (]CH); 115.19 (C-20, C-30); 124.52 (C-10); 125.01
(C-100); 127.72 (C-200, C-300); 127.91 (C-40); 128.43 (Ar); 132.25 (Ar);
136.66 (Ar); 159.41 (C], C-5); 164.21 (C]S, C-2); 178.52 (C]O, C-4).
HRMS, m/z ¼ 324.0936 found (calculated for C18H16N2O2S, Mþ
requires 324.0932).
5.1.3.2. (5Z)-2-ethylsulfanyl-3-methyl-5-(4-methyloxybenzylidene)-
3,5-dihydro-4H-imidazol-4-one (6b). Yield ¼ 54%. Yellow powder.
Mp ¼ 132e134 ꢀC. 1H NMR (DMSO-d6)
d
¼ 1.44 (t, 3H, J ¼ 7.3 Hz,
SCH2CH3); 3.05 (s, 3H, NCH3); 3.34 (q, 2H, J ¼ 4.3 Hz, SCH2CH3);
3.81 (s, 3H, OCH3); 6.83 (s,1H, ]CH); 7.1 (d, 2H, J ¼ 8.9 Hz, H-20, Ar);
5.1.2.6. (5Z)-3-Butyl-5-(4-methoxybenzylidene)-2-thioxo-imidazoli-
8.16 (d, 2H, J ¼ 8.8 Hz, H-30, Ar). 13C NMR (DMSO-d6)
d
¼ 14.25
din-4-one (5f). Yield ¼ 67%. Yellow powder. Mp ¼ 110e112 ꢀC. 1H
(CH3CH2S); 24.55 (CH3CH2S); 26.23 (NCH3); 55.27 (OCH3); 114.28
(]CH); 122.31 (C-20, Ar); 126.91 (C-30, Ar); 133.44 (C-10, Ar); 136.41
(C-40, Ar); 160.54 (C], C-5); 163.72 (C]N, C-2); 168.71 (C]O, C-4).
HRMS, m/z ¼ 276.0936 found (calculated for C14H16N2O2S, Mþ
requires 276.0932).
NMR (DMSO-d6)
d
¼ 0.88 (t, 3H, J ¼ 4.1 Hz, CH3CH2CH2CH2N); 1.28
(sext, 2H, J ¼ 7.3 Hz, CH3CH2CH2CH2N); 1.58 (quint, 2H, J ¼ 7 Hz,
CH3CH2CH2CH2N); 3.76 (t, 2H, J ¼ 7.3 Hz, CH3CH2CH2CH2N); 3.80 (s,
3H, OCH3); 6.57 (s, 1H, ]CH); 6.96 (d, 2H, J ¼ 8.8 Hz, H-20, Ar); 7.74
(d, 2H, J ¼ 8.8 Hz, H-30, Ar); 12.21 (br s,1H, NH). 13C NMR (DMSO-d6)
d
¼
13.53 (CH3CH2CH2CH2N); 19.4 (CH3CH2CH2CH2N); 29.30
5.1.3.3. (5Z)-5-(Benzo[1,3]dioxol-5-yl)methylene-2-ethylsulfanyl-3-
(CH3CH2CH2CH2N); 40.25 (CH3CH2CH2CH2N); 55.31 (OCH3); 113.30
(]CH); 114.34 (C-20, Ar); 124.31 (C-10, Ar); 124.37 (C], C-5); 132.27
(C-30, Ar); 160.32 (C-40, Ar); 164.16 (C]S, C-2); 178.01 (C]O, C-4).
HRMS, m/z ¼ 290.1086 found (calculated for C15H18N2O2S, Mþ
requires 290.1089).
methyl-3,5-dihydro-4H-imidazol-4-one (6c). Yield ¼ 72%. Yellow
powder. Mp ¼ 152e154 ꢀC. 1H NMR (DMSO-d6)
d
¼ 1.55 (t, 3H,
J ¼ 7.4 Hz, SCH2CH3); 3.17 (s, 3H, NCH3); 3.40 (q, 2H, J ¼ 7 Hz,
SCH2CH3); 6.01 (s, 2H, OCH2O); 6.82 (d, 1H, J ¼ 8 Hz, H-50, Ar); 6.83
(s, 1H, ]CH); 7.37 (dd, 1H, J ¼ 8.1 Hz, H-60, Ar); 8.05 (s, 1H, H-20, Ar).
13C NMR (DMSO-d6)
d
¼ 14.71 (SCH2CH3); 25.60 (SCH2CH3); 26.91
5.1.2.7. (5Z)-5-(Benzo[1,3]dioxol-5-yl)methylene-3-butyl-2-thioxo-
(NCH3); 101.80 (OCH2O); 108.82 (C-50, Ar); 11.21 (C-20, Ar); 124.02
(CH]); 128.41 (C-60, Ar); 129.51 (C-10, Ar); 137.50 (C], C-5); 148.31
(C-30, C-40, Ar); 149.51 (C-30, C-40, Ar); 164.11 (C]N, C-2); 170.31
imidazolidin-4-one (5g). Yield ¼ 75%. Yellow powder. Mp ¼ 118e
120 ꢀC. 1H NMR (CDCl3)
d
¼ 0.94 (t, 3H, J ¼ 7 Hz, CH3); 1.37 (sext, 2H,
J ¼ 7 Hz, CH2CH3); 1.70 (quint, 2H, J ¼ 7.5 Hz, CH3CH2CH2); 3.89 (t, 2H,
J ¼ 7.5 Hz, CH2N); 6.02 (s, 2H, OCH2O); 6.65 (s, 1H, CH]); 6.86 (d,1H,
J ¼ 8Hz, H-50, Ar); 6.94 (d,1H, J ¼ 1.5 Hz, H-60, Ar); 7.00 (dd,1H, J ¼ 8.1,
(C]O, C-4). HRMS, m/z
C
¼
290.0730 found (calculated for
14H14N2O3S, Mþ requires 290.725).
1.5 Hz, H-20, Ar); 9.40 (br s, 1H, NH). 13C NMR (CDCl3)
d
¼ 10.77
5.1.3.4. (5Z)-2-Ethylsulfanyl-3-methyl-5-(4-phenylmethyloxybenzy-
(CH3CH2CH2CH2N); 13.55 (CH3CH2CH2CH2N); 29.71 (tm, J ¼ 130 Hz,
CH3CH2CH2); 41.32(tt, J¼ 141 Hz, CH2N); 101.91 (t, J¼ 174 Hz, OCH2O);
108.71 (dt, J ¼ 164 Hz, C-50, Ar); 110.81 (d, J ¼ 167 Hz, C-20, Ar); 114.02
(dt, J ¼ 162 Hz, CH]); 125.03 (dt, J ¼ 163 Hz, C], C-5); 125.11 (d,
J ¼ 5 Hz, C-60, Ar); 126.81 (C-10, Ar); 148.62(C-30, C-40, Ar); 149.12 (C-30,
C-40,Ar);164.02(C]O, C-4);178.11(C]S,C-2).HRMS, m/z¼ 304.0880
found (calculated for C15H16N2O3S, Mþ requires 304.0882).
lidene)-3,5-dihydro-4H-imidazol-4-one (6d). Yield ¼ 70%. Yellow
powder. Mp ¼ 174e176 ꢀC. 1H NMR (DMSO-d6)
d
¼ 1.43 (t, 3H,
J ¼ 7.3 Hz, CH3CH2S); 3.04 (s, 3H, NCH3); 3.31 (q, 2H, J ¼ 7.1 Hz,
CH3CH2S); 5.17 (s, 2H, PhCH2O); 6.83 (s, 1H, ]CH); 7.07 (d, 2H,
J ¼ 8.8 Hz, H-20, Ar); 7.37e7.46 (m, 5H, J ¼ 7.1 Hz, H-200, H-300, H-400,
Ar); 8.15 (d, 2H, J ¼ 8.8 Hz, H-30, Ar). 13C NMR (DMSO-d6)
¼ 14.25
d
(CH3CH2S); 24.54 (NCH3); 26.24 (CH3CH2S); 69.27 (PhCH2O);
115.15 (]CH); 122.22 (C], C-5); 127.13 (C-40, Ar); 127.73
(C-20, C-30, Ar); 127.91 (C-200, Ar); 128.41 (C-20, C-30, Ar);
133.43 (C-300, Ar); 136.49 (C-10, Ar); 136.66 (C-400, Ar); 159.62
(C-100, Ar); 163.79 (C]N, C-2); 168.75 (C]O, C-4). HRMS,
m/z ¼ 352.1241 found (calculated for C20H20N2O2S, Mþ requires
352.1245).
5.1.3. Standard procedure of S-alkylation of 5-arylidene-2-thioxo-
imidazoline-4-one 5 for the synthesis of 5-arylidene-2-ethylsulfanyl-
3,5-dihydro-4H-imidazoline-4-one 6(aef)
In a 25 ml two necked room-bottomed flask, provided with a
magnetic stirrer and reflux condenser, a suspension of 5-arylidene

W.K. Coulibaly et al. / European Journal of Medicinal Chemistry 58 (2012) 581e590
587
5.1.3.5. (5Z)-5-(4-Butyloxybenzylidene)-2-ethylsulfanyl-3-methyl-
3,5-dihydro-4H-imidazol-4-one (6e). Yield ¼ 88%. White powder.
5.1.4.2. 1,2-Bis-[(5Z)-5-(1,3-benzodioxol-5-yl)methylene-3-methyl-4-
oxo-3,5-dihydro-4H-imidazol-2-yl]ethylene diamine (8b). Prepared
from 7a: 1 equiv. Reactions conditions: 120 ꢀC, 30 min. Yield ¼ 25%.
Mp ¼ 108e110 ꢀC. 1H NMR (CDCl3)
d
¼ 0.99 (t, 3H, J ¼ 7.4 Hz,
CH3CH2CH2CH2O); 1.51 (sext, 2H, J ¼ 7.8 Hz, CH3CH2CH2CH2O); 1.52
(t, 3H, J ¼ 7.4 Hz, CH3CH2S); 1.82 (quint, 2H, J ¼ 6.8 Hz,
CH3CH2CH2CH2O); 3.15 (s, 3H, CH3N); 3.75 (qt, 2H, J ¼ 7.4 Hz,
CH3CH2S); 4.02 (t, 2H, J ¼ 6.5 Hz, CH3CH2CH2CH2O); 6.92 (dd, 2H,
J ¼ 8.9 Hz, H-20, Ar); 6.92 (s, 1H, ]CH); 8.11 (dd, 2H, J ¼ 8.6 Hz, H-30,
Orange powder. Mp > 260 ꢀC. 1H NMR (DMSO-d6)
d
¼ 2.96 (s, 6H,
NCH3); 3.72 (s, 4H, NH(CH2)2NH); 5.98 (s, 4H, OCH2O); 6.37 (s, 2H, ]
CH); 6.84 (d, 2H, J ¼ 8.1 Hz, H-60, Ar); 7.40 (dd, 2H, J ¼ 7.2 Hz, H-50, Ar);
7.80 (br s, 2H, NH); 7.90 (s, 2H, H-20, Ar). 13C NMR (DMSO-d6)
d
¼ 25.41
(NCH3); 40.30 (N(CH2)2N); 100.93 (OCH2O); 108.25 (C-20, Ar); 109.52
(C-50, Ar); 112.97 (C-60, Ar); 125.13 (C]CH); 130.28 (C-10, Ar); 138.73
(C ¼ , C-5); 146.62 (C-40, Ar); 147.16 (C-30, Ar); 158.26 (C]N, C-2);
169.48 (C]O, C-4). HRMS, m/z ¼ 517.1838 found (calculated for
Ar). 13C NMR (CDCl3)
d
¼
13.83 (CH3CH2CH2CH2O); 14.33
(CH3CH2S); 19.21 (CH3CH2CH2CH2O); 25.11 (CH3CH2CH2CH2O);
26.49 (NCH3); 31.19 (CH3CH2S); 67.77 (CH3CH2CH2CH2O); 114.71
(C-20, Ar); 123.99 (]CH); 127.24 (C], C-5); 133.68 (C-30, Ar); 136.76
(C-10, Ar); 160.57 (C-40, Ar); 163.11 (C]N, C-2); 170.04 (C]O, C-4).
HRMS, m/z ¼ 341.1300 found (calculated for C17H22N2O2SNa,
[M þ Na]þ requires 341.12997).
C
26H25N6O6, [M þ H]þ requires 517.1830).
5.1.4.3. 1,2-Bis-[(5Z)-5-(4-benzyloxyphenyl)methylene-3-methyl-4-oxo-
3,5-dihydro-4H-imidazol-2-yl]ethylene diamine (8c). Prepared from 7a:
1 equiv. Reactions conditions: 120 ꢀC, 30 min. Yield ¼ 11%. Orange
5.1.3.6. (5Z)-2-Ethylsulfanyl-3-methyl-5-(4-phenylmethyloxybenz-
ylidene)-3,5-dihydro-4H-imidazol-4-one (6f). Yield ¼ 78%. Yellow
powder. Mp > 260 ꢀC. 1H NMR (DMSO-d6)
d
¼ 2.96 (s, 6H, NCH3); 3.72
(s, 4H, NH(CH2)2NH); 5.09 (s, 4H, PhCH2O); 6.40 (s, 2H, ]CH); 6.92
(d, 4H, J ¼ 8.3 Hz, H-20, Ar); 7.38 (m, 10H, J ¼ 6.1 Hz, H-200, H-400, Ar);
7.77 (br s, 2H, NH); 8.01 (d, 4H, J ¼ 8.4 Hz, H-400, Ar). 13C NMR (DMSO-
powder. Mp ¼ 136e138 ꢀC. 1H NMR (DMSO-d6)
d
¼ 0.88 (t, 3H,
J ¼ 7.2 Hz, NCH2CH2CH2CH3); 1.22 (sext, 2H, J ¼ 7.6 Hz,
NCH2CH2CH2CH3); 1.43 (t, 3H, J ¼ 7.4 Hz, CH3CH2S); 1.54 (sext, 2H,
J ¼ 7.7 Hz, NCH2CH2CH2CH3); 3.33 (q, 2H, J ¼ 7.3 Hz, CH3CH2S);
6.08 (s, 2H, PhCH2O); 6.81 (s, CH]); 7.55 (dd, 5H, J ¼ 6.9 Hz, H-200,
H-300, H-40, Ar); 8.02 (d, 4H, J ¼ 1.7 Hz, H-20, H-30, Ar). 13C NMR
d6)
d
¼ 25.38 (NH(CH2)2NH); 40.29 (NCH3); 69.09 (PhCH2O); 112.83
(]CH); 114.70 (C], C-5); 127.60 (C-2); 127.79 (C-20, Ar); 128.39 (C-30,
Ar); 128.75 (C-400, Ar); 131.70 (C-300, Ar); 136.92 (C-10, Ar); 138.57 (C-40,
Ar); 157.71 (C-100, Ar); 158.24 (C]N, C-2); 170.01 (C]O, C-4). HRMS,
m/z ¼ 641.2872 found (calculated for C38H37N6O4, [M þ H]þ requires
641.2871).
(DMSO-d6)
d
¼ 13.41 (CH3CH2CH2CH2N); 14.18 (CH3CH2S); 19.31
(CH3CH2CH2CH2N); 24.76 (CH3CH2CH2CH2N); 30.30 (CH3CH2S);
40.29 (CH3CH2CH2CH2N); 101.52 (PhCH2O); 108.57 (]CH); 110.01
(C], C-5); 122.38 (Ar); 127.89 (Ar); 128.59 (Ar); 136.53 (Ar);
147.57 (Ar); 148.79 (Ar); 163.64 (C]N, C-2); 168.64 (C]O, C-4).
HRMS, m/z ¼ 394.1712 found (calculated for C22H26N2O2S, Mþ
requires 394.1715).
5.1.4.4. 1,2-Bis-[(5Z)-5-(4-butyloxyphenyl)methylene-3-methyl-4-oxo-
3,5-dihydro-4H-imidazol-2-yl]ethylene diamine (8d). Prepared from
7a: 1.5 equiv. Reactions conditions: 100 ꢀC, 20 min. Yield ¼ 10%.
1
Orange powder. Mp ¼ 220 ꢀC. H NMR (DMSO-d6)
d
¼ 0.92 (t, 6H,
J ¼ 6.2 Hz, CH3(CH2)3O); 1.42 (sext, 4H, J ¼ 3.3 Hz, CH3CH2CH2CH2O);
1.67 (quint, 4H, J ¼ 3.2 Hz, CH3CH2CH2CH2O); 2.96 (s, 6H, NCH3); 3.72
(s, 4H, N(CH2)2N); 3.92 (t, 4H, J ¼ 7.5 Hz, CH3CH2CH2CH2O); 6.36 (s,
2H, ]CH); 6.83 (d, 4H, J ¼ 8.5 Hz, H-20, Ar); 7.78 (br s, 2H, NH); 8.01 (d,
5.1.4. Standard procedure for the synthesis of N,N0-bis[(5Z)-5-
arylidene-4-oxo-3,5-dihydro-4H-imidazolin-2-yl]diamine 8(aed),
9(aef), 10(aeg) by sulphur/nitrogen displacement under
microwave irradiation
4H,
J
¼
7.9 Hz, H-30, Ar). 13C NMR (DMSO-d6)
d
¼
13.66
A mixture of 5-arylidene-2-ethylsulfanyl-3,5-dihydro-4H-imi-
dazoline-4-one 6 (2 mmol,1 equiv) and ethylenediamine 7a (120 or
180 mg, 1 or 1.5 mmol, 1 or 1.5 equiv) or piperazine 7b (172 mg,
2 mmol, 1 equiv) or N,N0-bis(3-aminopropyl)piperazine 7c (0.2 g,
1 mmol, 0.5 equiv) was placed in a borosilicate glass vial (10 ml)
with a TeflonÒ magnetic stir bar and sealed with a snap cap. The
glass tube was then introduced into an ExplorerÒ 24 CEM micro-
wave cavity (P ¼ 300 W). The stirred mixture was irradiated at
100e160 ꢀC (with a power of 200 W) for 20e45 min. After micro-
wave dielectric heating, the crude reaction mixture was allowed to
cool down to room temperature and 10 ml of cooled methanol
(4 ꢀC) were added directly in the glass vial. The resulting precipi-
tated product 8 was filtered off, washed with 2 ꢃ 5 ml of methanol
and dried under high vacuum (10ꢂ2 Torr) at room temperature for
1 h. After 1H NMR analysis, the desired product 8 was purified by
recrystallization from methanol.
(CH3(CH2)2CH2O); 18.67 (CH3CH2CH2CH2O); 25.47 (NCH3); 30.64
(CH3CH2CH2CH2O); 40.61 (NH(CH2)2NH); 67.03 (CH3(CH2)2CH2O);
112.95 (]CH); 114.30 (C-20, Ar); 128.35 (C-10, Ar); 131.74 (C-30, Ar);
138.42 (C], C-5); 158.07 (C]N, C-2); 158.16 (C-40, Ar); 169.55 (C]O,
C-4). HRMS, m/z ¼ 541.2865 found (calculated for C32H41N6O4,
[M þ H]þ requires 541.2871).
5.1.4.5. 1,4-Bis-[(5Z)-5-phenylmethylene-3-methyl-4-oxo-3,5-dihydro-
4H-imidazol-2-yl]piperazine (9a). Prepared from 7b: 1 equiv. Reac-
tion conditions: 160 ꢀC, 30 min. Yield ¼ 47%. Orange powder.
Mp > 260 ꢀC. 1H NMR (DMSO-d6)
d
¼ 3.25 (s, 6H, NCH3); 3.81 (s, 8H,
N(CH2)4N); 6.60 (s, 2H, C]CH); 7.28e7.43 (m, 8H, J ¼ 7.3 Hz, H-3,
H-4, Ar); 8.10 (d, 4H, J ¼ 7.3 Hz, H-2, Ar). 13C NMR (DMSO-d6)
d
¼ 29.60 (NCH3); 46.68 (N(CH2)4N); 112.04 (]CH); 127.72 (C-40, Ar);
128.28 (C-30, Ar); 130.26 (C-20, Ar); 134.99 (C-10, Ar); 140.52 (C],
C-5); 162.54 (C]N, C-2); 169.66 (C]O, C-4). HRMS, m/z ¼ 477.2007
found (calculated for C26H26N6O2Na, [M þ Na]þ requires 477.2009).
5.1.4.1. 1,2-Bis-[(5Z)-3-methyl-5-(4-methoxyphenyl)methylene-4-oxo-
3,5-dihydro-4H-imidazol-2-yl]ethylene diamine (8a). Prepared from
7a: 1 equiv. Reaction conditions: 120 ꢀC, 30 min. Yield ¼ 20%.
5.1.4.6. 1,4-Bis-[(5Z)-3-methyl-5-(4-methoxyphenyl)methylene-4-
oxo-3,5-dihydro-4H-imidazol-2-yl]piperazine (9b). Prepared from
7b: 1 equiv. Reaction conditions: 160 ꢀC, 35 min. Yield ¼ 72%. Orange
Orange powder. Mp > 260 ꢀC. 1H NMR (DMSO-d6)
d
¼ 2.96 (s, 6H,
NCH3); 3.74 (s, 4H, NH(CH2)2NH); 3.74 (s, 6H, OCH3); 6.39 (s, 2H,
powder. Mp > 260 ꢀC. 1H NMR (DMSO-d6)
d
¼ 3.22 (s, 6H, NCH3); 3.74
]CH); 6.85 (d, J ¼ 8.6 Hz, 4H, H-20, Ar); 7.76 (br s, 2H, NH); 8.01
(br s, 8H, C4H10N2); 3.78 (s, 6H, OCH3); 6.61 (s, 2H, ]CH); 6.95 (d, 4H,
J ¼ 8.8 Hz, H-20, Ar); 8.08 (d, 4H, J ¼ 8.8 Hz, H-30, Ar). 13C NMR (DMSO-
(d, 4H, J ¼ 8.6 Hz, H-30, Ar). 13C NMR (DMSO-d6)
d
¼ 25.39 (NCH3);
40.62 (N(CH2)2N); 54.98 (OCH3); 112.90 (C]CH), 113.83 (C-20, Ar);
128.54 (C-10, Ar); 131.71 (C-30, Ar); 138.49 (C ¼ , C-5); 158.20 (C-40,
Ar); 158.63 (C]N, C-2); 169.55 (C]O, C-4). HRMS, m/
z ¼ 489.2240 found (calculated for C26H29N6O4, [M þ H]þ requires
489.2248).
d6)
d
¼ 29.62 (NCH3); 46.68 (N(CH2)4N);55.80 (OCH3); 114.70 (C-30,Ar);
117.56 (]CH); 128.75 (C-10, Ar); 132.86 (C-20, Ar); 137.73 (C], C-5);
160.23 (C-40, Ar); 161.04 (C]N, C-2); 171.45 (C]O, C-4). HRMS,
m/z ¼ 515.2399 found (calculated for C28H31N6O4, [M þ H]þ requires
515.2401).

588
W.K. Coulibaly et al. / European Journal of Medicinal Chemistry 58 (2012) 581e590
5.1.4.7. 1,4-Bis-[(5Z)-5-(1,3-benzodioxol-5-yl)methylene-3-methyl-
4-oxo-3,5-dihydro-4H-imidazol-2-yl]piperazine (9c). Prepared from
7b: 1 equiv. Reaction conditions: 140 ꢀC, 45 min. Yield ¼ 22%.
J
¼
6.6
Hz;
NCH2CH2CH2N(CH2)4N);
2.28
(s,
8H;
NCH2CH2CH2N(CH2)4N); 3.02 (s, 6H, NCH3); 3.44 (quint, 4H,
J ¼ 6.7 Hz, NCH2CH2CH2N(CH2)4N); 3.75 (s, 6H, OCH3); 6.35 (s,
2H; ¼CH); 6.90 (d, 4H, J ¼ 9.7 Hz, H-20, Ar); 7.59 (br s, 2H, NH); 8.20
Orange powder. Mp > 260 ꢀC. 1H NMR (DMSO-d6)
d
¼ 3.22 (s,
6H, NCH3); 3.75 (s, 8H, N(CH2)4N); 6.05 (s, 4H, OCH2O); 6.58 (s, 2H,
(d, 4H, J ¼ 9.6 Hz, H-30, Ar). 13C NMR (DMSO-d6)
d
¼ 25.52 (NCH3);
]CH); 6.94 (d, 2H, J ¼ 1.5 Hz, H-60, Ar); 7.48 (dd, 2H, J ¼ 9.6 Hz, H-50,
25.92 (NCH2CH2CH2N(CH2)4N); 40.30 (NCH2CH2CH2N(CH2)4N);
52.82 (N(CH2)4N); 55.48 (NCH2CH2CH2N(CH2)4N); 112.04 (¼CH);
127.19 (C-40, Ar); 128.18 (C-30, Ar); 130.06 (C-20, Ar); 135.99 (C-10,
Ar); 140.52 (C ¼ , C-5); 158.54 (C]N, C-2); 169.62 (C]O, C-4).
HRMS, m/z ¼ 569.3354 found (calculated for C32H41N8O2, [M þ H]þ
requires 569.3347).
Ar); 7.94 (s, 2H, H-20, Ar). 13C NMR (DMSO-d6)
d
¼ 29.68 (NCH3);
46.64 (N(CH2)4N); 101.54 (OCH2O); 108.69 (C-20, Ar); 110.44 (C-50,
Ar); 117.38 (C-10, Ar); 126.52 (C-60, Ar); 127.89 (]CH); 130.39 (C],
C-5); 146.53 (C-40, Ar); 148.03 (C-30, Ar); 157.71 (C]N, C-2); 161.14
(C]O, C-4). HRMS, m/z
C
¼
543.1986 found (calculated for
28H27N6O6, [M þ H]þ requires 543.1986).
5.1.4.12. N,N0-bis-[(5Z)-3-methyl-5-(4-methoxyphenylmethylene-4-
oxo-3,5-dihydro-4H-imidazol-2-yl]-1,4-bis-(3-aminopropyl)pipera-
zine (10b). Prepared from 7c: 0.5 equiv. Reaction conditions:
160 ꢀC, 30 min. Yield ¼ 22%. Yellow powder. Mp > 260 ꢀC. 1H NMR
5.1.4.8. 1,4-Bis-[(5Z)-5-(4-benzyloxyphenyl)methylene-3-methyl-4-
oxo-3,5-dihydro-4H-imidazol-2-yl]piperazine (9d). Prepared from
7b: 1 equiv. Reaction conditions: 160 ꢀC, 30 min. Yield ¼ 62%.
Orange powder. Mp > 260 ꢀC. 1H NMR (DMSO-d6)
d
¼ 3.22 (s, 6H,
(DMSO-d6)
(t, 4H,
d
¼ 1.79 (t, 4H, J ¼ 6.3 Hz, NCH2CH2CH2N(CH2)4N); 2.28
NCH3); 3.74 (s, 8H, C4H10N2); 5.15 (s, 4H, PhCH2O); 6.61 (s, 2H, ]
CH); 7.02 (d, 4H, J ¼ 8.9 Hz, H-20, Ar); 7.36e7.44 (m, 10H, J ¼ 4.5 Hz,
H-200, H-300, H-400, Ar); 8.07 (d, 2H, J ¼ 7.6 Hz, H-30, Ar). 13C NMR
J
¼
6.6 Hz, NCH2CH2CH2N(CH2)4N); 2.28 (s, 8H,
NCH2CH2CH2N(CH2)4N); 3.02 (s, 6H, NCH3); 3.44 (quint, 4H,
J ¼ 6.7 Hz, NCH2CH2CH2N(CH2)4N); 3.75 (s, 6H, OCH3); 6.35 (s, 2H,
]CH); 6.90 (d, 4H, J ¼ 9.7 Hz, H-20, Ar); 7.59 (br s, 2H, NH); 8.20 (d,
(DMSO-d6)
d
¼ 29.4 (NCH3); 46.07 (N(CH2)4N); 69.21 (OCH2Ar);
114.85 (C-30, Ar); 116.81 (]CH); 127.74 (C-200, Ar); 127.90 (C-400, Ar);
128.13 (C-10, Ar); 128.43 (C-300, Ar); 132.42 (C-20, Ar); 136.82 (C],
C-5); 136.97 (C-10, Ar); 158.49 (C-40, Ar); 160.36 (C]N, C-2); 170.93
4H, J ¼ 9.6 Hz, H-3, Ar). 13C NMR (DMSO-d6)
¼ 25.45 (NCH3); 25.92
d
(NCH2CH2CH2N(CH2)4N); 40.28 (NCH2CH2CH2N(CH2)4N); 52.84
(NCH2CH2CH2N(CH2)4N); 55.51 (NCH2CH2CH2N(CH2)4N); 112.61
(]CH); 113.78 (C-20, Ar); 128.65 (C-10, Ar); 138.57 (C-40, Ar); 157.84
(C]N, C-2); 158.62 (C], C-5); 169.60 (C]O, C-4). HRMS, m/
z ¼ 629.3557 found (calculated for C34H45N8O4, [M þ H]þ requires
629.3558).
(C]O, C-4). HRMS, m/z
C
¼
667.3023 found (calculated for
40H39N6O4, [M þ H]þ requires 667.3028).
5.1.4.9. 1,4-Bis-[(5Z)-5-(4-benzyloxyphenyl)methylene-3-butyl-4-
oxo-3,5-dihydro-4H-imidazol-2-yl]piperazine (9e). Prepared from
7b: 1 equiv. Reaction conditions: 160 ꢀC, 30 min. Yield ¼ 15%. Yellow
5.1.4.13. N,N0-bis-[(5Z)-5-(1,3-benzodioxol-5-yl)methylene-3-methyl-
4-oxo-3,5-dihydro-4H-imidazol-2-yl]-1,4-bis-(3-aminopropyl)pipera-
zine (10c). Prepared from 7c: 0.5 equiv. Reaction conditions: 160 ꢀC,
30 min. Yield ¼ 36%. Yellow powder. Mp > 260 ꢀC. 1H NMR (DMSO-
powder. Mp ¼ 252e254 ꢀC. 1H NMR (DMSO-d6)
d
¼ 0.90 (t, 6H,
J ¼ 5.8 Hz, CH3(CH2)3N); 1.25 (m, 4H, J ¼ 5.5 Hz, CH3CH2CH2CH2N);
1.61 (m, 4H, J ¼ 3.3 Hz, CH3CH2CH2CH2N); 3.71 (t, 4H, J ¼ 3.2 Hz,
CH3CH2CH2CH2N); 5.15 (s, 4H, ArCH2O); 6.61 (s, 2H, ]CH); 7.03 (d,
4H, J ¼ 8 Hz, H-30, Ar), 7.40e7.44 (m,10H, J ¼ 4.3e8.18 Hz, H-200, H-400,
Ar); 8.08 (d, 4H, J ¼ 8 Hz, H-20, Ar). 13C NMR (DMSO-d6)
d6)
d
¼ 1.79 (t, 4H, J ¼ 13.9 Hz, NCH2CH2CH2N(CH2)4N); 2.37 (t, 4H,
J ¼ 6.2 Hz, NCH2CH2CH2N(CH2)4N); 2.37 (s, 8H; N(CH2)4N); 3.02 (s,
6H, NCH3); 3.44 (t, 4H, J ¼ 13.2 Hz, NCH2CH2CH2N(CH2)4N); 5.99 (s,
OCH2O); 6.34 (s, 2H, ]CH); 6.87 (d, 2H, J ¼ 8.0 Hz, H-60, Ar); 7.35 (d,
2H, J ¼ 7.9 Hz, H-50, Ar); 7.65 (br s, 2H, NH); 7.96 (s, 2H, H-20, Ar). 13C
d
¼ 13.64 (CH3CH2CH2CH2N); 19.78 (CH3CH2CH2CH2N); 30.43
(CH3CH2CH2CH2N); 41.18 (CH3CH2CH2CH2N); 46.91 (N(CH2)4N);
70.34 (OCH2Ar); 115.73 (C-30, Ar); 117.79 (]CH); 127.86 (C-200, Ar);
128.144 (C-400, Ar); 128.77 (C-300, Ar); 128.98 (C-100, Ar); 132.91
(C-10, Ar); 132.91 (C-20, Ar); 137.58 (C], C-5); 159.37 (C-40, Ar);
160.84 (C]N, C-2); 171.62 (C]O, C-4). HRMS, m/z ¼ 751.3962 found
(calculated for C46H51N6O4, [M þ H]þ requires 751.3966).
NMR (DMSO-d6)
d
¼ 25.46 (NCH3); 25.84 (NCH2CH2CH2N(CH2)4N);
40.22 (NCH2CH2CH2N(CH2)4N); 52.75 (N(CH2)4N); 55.48 (NCH2CH2-
CH2N(CH2)4N); 100.91 (OCH2O); 108.20 (]CH); 109.34 (C-60, Ar);
112.61 (C-50, Ar); 125.15 (C-20, Ar); 130.34 (C-10, Ar); 138.84 (C],
C-5); 146.58 (C-40, Ar); 147.14 (C-30, Ar); 157.94 (C]N, C-2); 169.51
(C]O, C-4). HRMS, m/z ¼ 657.3146 found (calculated for C34H41N8O6,
[M þ H]þ requires 657.3144).
5.1.4.10. 1,4-Bis-[(5Z)-5-(4-butyloxyphenyl)methylene-3-methyl-4-
oxo-3,5-dihydro-4H-imidazol-2-yl]piperazine (9f). Prepared from
7b: 1 equiv. Reaction conditions: 160 ꢀC, 30 min. Yield ¼ 26%. Yellow
5.1.4.14. N,N0-bis-[(5Z)-3-butyl-5-(1,3-benzodioxol-5-yl)methylene-
4-oxo-3,5-dihydro-4H-imidazol-2-yl]-1,4-bis-(3-aminopropyl)piper-
azine (10d). Prepared from 7c: 0.5 equiv. Reaction conditions: 150 ꢀC,
30 min. Yield ¼ 36%. Yellow powder. Mp ¼ 262 ꢀC. 1H NMR (DMSO-d6)
powder. Mp > 260 ꢀC. 1H NMR (DMSO-d6)
d
¼ 0.92 (t, 6H, J ¼ 7.3 Hz,
CH3(CH2)3O); 1.42 (sext, 4H, J ¼ 7.2 Hz, CH3CH2CH2CH2O); 1.69
(quint, 4H, 7.2 Hz, CH3CH2CH2CH2O); 3.22 (s, 6H,
J
¼
NCH3); 3.73 (N(CH2)4N); 4.01 (t, 4H, J ¼ 6 Hz, CH3(CH2)2CH2O); 6.61
d
¼ 0.87 (t, 6H, J ¼ 7.1 Hz, CH3CH2CH2CH2N); 1.23 (sext, 4H, J ¼ 6.5 Hz,
(s, 2H, ]CH); 6.94 (d, 4H, J ¼ 8.6 Hz, H-20, Ar); 8.06 (d, 4H, J ¼ 8.5 Hz,
CH3CH2CH2CH2N); 1.46 (quint, 4H, J ¼ 6.6 Hz, CH3CH2CH2CH2N); 1.79
(t, 4H, J ¼ 5.4 Hz, NCH2CH2CH2N(CH2)4N); 2.36 (t, 8H, J ¼ 5.9 Hz,
NCH2CH2CH2N(CH2)4N); 3.44 (t, 4H, J ¼ 4.2 Hz, NCH2CH2CH2N-
(CH2)4N); 3.53 (t, 4H, J¼ 6.3 Hz, CH3CH2CH2CH2N); 5.99 (s, 4H, OCH2O);
6.32 (s, 2H, ]CH); 6.87 (d, 2H, J¼ 8.1 Hz, H-60,Ar);7.35(d,2H,J¼ 8.2 Hz,
H-50, Ar); 7.59 (br s, 2H, NH); 7.95 (s, 2H, H-20, Ar). 13C NMR (DMSO-d6)
H-30, Ar). 13C NMR (DMSO-d6)
d
¼ 13.75 (CH3CH2CH2CH2O);
19.04 (CH3CH2CH2CH2O); 29.60 (NCH3); 31.30 (CH3CH2CH2CH2O);
46.71 (N(CH2)4N);68.30 (CH3CH2CH2CH2O); 115.35 (C-30, Ar); 117.69
(]CH); 128.65 (C-10, Ar); 132.87 (C-20, Ar); 137.68 (C], C-5); 159.71
(C-40, Ar); 161.05 (C]N, C-2); 171.46 (C]O, C-4). HRMS,
m/z ¼ 599.3334 found (calculated for C34H43N6O4, [M þ H]þ requires
599.3340).
d
¼
13.56 (CH3CH2CH2CH2N); 19.27 (CH3CH2CH2CH2N); 21.13
(CH3CH2CH2CH2N); 25.93 (NCH2CH2CH2N(CH2)4N); 30.36 (CH3CH2-
CH2CH2N); 38.15 (NCH2CH2CH2N(CH2)4N); 52.81 (NCH2CH2CH2-
N(CH2)4N); 55.48 (NCH2CH2CH2N(CH2)4N); 100.91 (OCH2O); 108.20
(¼CH); 109.34 (C-60, Ar); 112.57 (C-50, Ar); 125.14 (C-20, Ar); 130.39
(C-40, Ar); 133.90 (C-10, Ar); 138.64 (C-30, Ar); 138.90 (C], C-5); 146.58
(C]N, C-2); 147.15 (C]O, C-4). HRMS, m/z ¼ 741.4083 found (calcu-
lated for C40H53N8O6, [M þ H]þ requires 741.4083).
5.1.4.11. N,N0-Bis-[(5Z)-5-phenylmethylene-3-methyl-4-oxo-3,5-
dihydro-4H-imidazol-2-yl)-1,4-bis-(3-aminopropyl)piperazine (10a).
Prepared from 7c: 0.5 equiv. Reaction conditions: 150 ꢀC, 30 min.
Yield ¼ 26%. Yellow powder. Mp > 260 ꢀC. 1H NMR (DMSO-d6)
d
¼ 1.79 (t, 4H, J ¼ 6.3 Hz, NCH2CH2CH2N(CH2)4N); 2.28 (t, 4H,

W.K. Coulibaly et al. / European Journal of Medicinal Chemistry 58 (2012) 581e590
589
5.1.4.15. N,N0-bis-[(5Z)-5-(4-benzyloxyphenyl)methylene-3-methyl-4-
5.2.2. Kinase preparations and assays
Kinase activities were assayed in buffer A, at 30 ꢀC, at a final ATP
concentration of 15 M. Blank values were subtracted and activities
expressed in percent of the maximal activity, i.e., in the absence of
inhibitors. Controls were performed with appropriate dilutions of
DMSO. The kinase peptide substrates were obtained from Proteo-
genix (Oberhausbergen, France).
oxo-3,5-dihydro-4H-imidazol-2-yl]-1,4-bis-(3-aminopropyl)piperazine
(10e). Prepared from 7c: 0.5 equiv. Reaction conditions: 160 ꢀC,
30 min. Yield ¼ 24%. Yellow powder. Mp > 260 ꢀC. 1H NMR (DMSO-d6)
m
d
¼ 1.80 (quint, 4H, J ¼ 6.7 Hz, HNCH2CH2CH2(CH2)4N); 2.41 (t, 4H,
J
¼
6.6 Hz, HNCH2CH2CH2(CH2)4N); 2.43 (s, 8H, HNCH2CH2-
5.2 Hz,
CH2(CH2)4N); 2.99 (s, 6H, NCH3); 3.42 (t, 4H,
J
¼
HNCH2CH2CH2(CH2)4N); 5.09 (s, 4H, PhCH2O); 6.35 (s, 2H, ]CH); 6.96
DYRK1A (rat recombinant, expressed in Escherichia coli as a GST
fusion protein) was purified by affinity chromatography on
glutathione-agarose and assayed in buffer A (þ0.15 mg BSA/mL)
(d, 4H, J ¼ 8.8 Hz, H-20, Ar); 7.32e7.42 (m, 10H, J ¼ 7.1 Hz, H-20, H-40,
Ar); 8.02 (d, 4H, J ¼ 8.8 Hz, H-30, Ar). 13C NMR (DMSO-d6)
d
¼ 25.42
(NCH3); 25.94 (HNCH2CH2CH2(CH2)4N); 39.15 (N(CH2)4N); 52.85
(HNCH2CH2CH2(CH2)4N); 55.52 (HNC H2CH2CH2(CH2)4N); 69.10
(PhCH2O); 112.52 (]CH); 114.62 (C-20, Ar); 127.58 (C-200, Ar); 127.77
(C-40, Ar); 128.35 (C-30, Ar); 128.87 (C-10, Ar); 131.63 (C-300, Ar); 136.88
(C-100, Ar); 138.67 (C-40, Ar); 157.67 (C], C-5); 157.86 (C]N, C-2);
169.56 (C]O, C-4). HRMS, m/z ¼ 781.4185 found (calculated for
using Woodtide (KKISGRLSPIMTEQ) (1.5 mg/assay) as a substrate, in
the presence of 15
a final volume of 30
m
M [
m
g-
33P] ATP (3000 Ci/mmol; 10 mCi/mL) in
L. After 30 min, incubation at 30 ꢀC, the
reaction was stopped by harvesting onto P81 phosphocellulose
papers (Whatman) using a FilterMate harvester (Packard) and were
washed in 1% phosphoric acid. Scintillation fluid was added and the
radioactivity measured in a Packard counter.
C
46H53N8O4, [M þ H]þ requires 781.4183).
CLK1 and CLK3 (mouse, recombinant, and expressed in E. coli as
GST fusion proteins) were assayed in buffer A (þ0.15 mg BSA/mL)
5.1.4.16. N,N0-Bis-[(5Z)-3-butyl-5-(4-benzyloxyphenyl)methylene-4-
oxo-3,5-dihydro-4H-imidazol-2-yl]-1,4-bis-(3-aminopropyl)pipera-
zine (10f). Prepared from 7c: 0.5 equiv. Reaction conditions: 160 ꢀC,
30 min. Yield ¼ 16%. Yellow powder. Mp ¼ 222e224 ꢀC. 1H NMR
with RS peptide (GRSRSRSRSRSR) (1 mg/assay).
GSK-3
using
SSPHQSpEDEEE) (pS stands for phosphorylated serine) [24].
a/
b
(porcine brain, native) was assayed in buffer A and
a
GSK-3 specific substrate (GS-1: YRRAAVPPSPSLSRH-
(DMSO-d6)
d
¼ 0.86 (t, 6H, J¼ 7.3 Hz, CH3CH2CH2CH2N); 1.22 (quint, 4H,
J
¼
7.4 Hz, CH3CH2CH2CH2N); 1.44 (quint, 4H,
J
¼
6.1 Hz,
CH3CH2CH2CH2N); 1.79 (quint, 4H, J ¼ 6.3 Hz, HNCH2CH2CH2(CH2)4N);
2.37 (t, 4H, J ¼ 6.1 Hz, HNCH2CH2CH2(CH2)4N); 2.39 (s, 8H,
HNCH2CH2CH2(CH2)4N); 3.45 (t, 4H, J ¼ 5.1 Hz, NHCH2CH2CH2-
(CH2)4N); 3.51 (t, 4H, J ¼ 6.6 Hz, CH3CH2CH2CH2N); 5.10 (s, 4H,
PhCH2O); 6.34 (s, 2H, ]CH); 6.97 (d, 4H, J ¼ 8.8 Hz, H-20, Ar); 7.30e7.41
(m,10H, J ¼ 6.8 Hz, H-200, H-300, H-400, Ar);7.53(brs, 2H, NH); 8.02 (d, 4H,
5.3. Cell-free assay for inhibition of
b-hematin formation
Inhibition of formation of -hematin in a cell-free assay was
b
observed by using the following procedure. A stock solution (10 mL)
of the studied compound (solution A) was prepared by dissolving
2
m
mol of that compound in a mixture of DMSO (1 mL) and HEPES
buffer 0.2 M (pH 7.0). A stock solution (10 mL) of hemin (solution B)
was prepared by dissolving 2 mol (1.3 mg) of hemin in a mixture of
J ¼ 8.7 Hz, H-30, Ar).13C NMR (DMSO-d6)
¼ 13.56 (CH3(CH2)3N); 19.27
d
(CH3CH2(CH2)2N); 25.96 (CH3CH2CH2CH2N); 30.37 (CH3CH2CH2-
CH2N); 38.11 (N(CH2)4N); 52.88 (HNCH2CH2CH2(CH2)4N); 55.53 (HNC
H2CH2CH2(CH2)4N); 69.11 (PhCH2O); 112.48 (]CH); 114.63 (C-20, Ar);
127.60 (C-200, Ar); 127.78 (C-400, Ar); 128.36 (C-300, Ar); 128.89 (C-10, Ar);
131.64 (C-30,Ar);136.90(C-40,Ar);157.30(C], C-5); 157.68(C]N, C-2);
169.60 (C]O, C-4). HRMS, m/z ¼ 865.5125 found (calculated for
m
aqueous sodium hydroxide 0.1 M (5 mL) and HEPES buffer 0.2 M.
The test solution of the studied compound was obtained by mixing
solution A (1 mL), solution B (1 mL), acetate buffer pH 5 (1 mL) and
HEPES buffer 0.2 M (2 mL). In the absence of compound 8 or 9 or 10,
b-hematin precipitated within a few minutes.
C
52H65N8O4, [M þ H]þ requires 865.5123).
Acknowledgments
5.1.4.17. N,N0-Bis-[(5Z)-5-(4-butoxyphenyl)methylene-3-methyl-4-
oxo-3,5-dihydro-4H-imidazol-2-yl]-1,4-bis-(3-aminopropyl)piperazine
(10g). Prepared from 7c: 0.5 equiv. Reaction conditions: 160 ꢀC,
30 min. Yield ¼ 21%. Yellow powder. Mp ¼ 262e264 ꢀC. 1H NMR
One of us (K.W.C.) wishes to thank the “Agence Universitaire de
la Francophonie AUF, contract Nꢀ0486” for a research fellowship.
Financial support of this program carried out under the French
National Cancer Institute “Cancéropôle Grand Ouest” by contracts
PRIR 04-8390 and ACI 04-2254, is gratefully acknowledged. We also
(DMSO-d6)
d
¼ 0.89 (t, 6H, J ¼ 7.4 Hz, CH3CH2CH2CH2O); 1.40 (sext,
4H, J ¼ 7.5 Hz, CH3CH2CH2CH2O); 1.65 (quint, 4H, J ¼ 6.7 Hz,
CH3CH2CH2CH2O); 1.79 (quint, 4H, J ¼ 6.3 Hz, HNCH2CH2CH2N-
(CH2)4N); 2.39 (t, 4H, J ¼ 6.8 Hz, HNCH2CH2CH2N(CH2)4N); 2.41 (s,
8H, HNCH2CH2CH2N(CH2)4N); 3.02 (s, 6H, NCH3); 3.44 (t, 4H,
J ¼ 5.6 Hz, HNCH2CH2CH2N(CH2)4N); 3.94 (t, 4H, J ¼ 6.5 Hz,
CH3CH2CH2CH2O); 6.34 (s, 2H, ]CH); 6.87 (d, 4H, J ¼ 8.8 Hz, H-20,
Ar); 7.59 (br s, 2H, NH); 8.01 (d, 4H, J ¼ 8.8 Hz, H-30, Ar). 13C NMR
thank J.J.V-E for inhibition of
b-hematin formation assays. This
research was also supported by grants from the “Fonds Unique
Interministériel” (FUI) PHARMASEA project (LM, JPB), the “Associ-
ation France-Alzheimer (Finistère)” (LM), “CRITT-Santé Bretagne”
(LM) and “Fondation Jérôme Lejeune” (LM).
References
(DMSO-d6)
d
¼ 14.12 (CH3(CH2)3O); 19.17 (CH3CH2CH2CH2O); 25.94
(NCH3); 26.47 (HNCH2CH2CH2N(CH2)4N); 31.17 (CH3CH2CH2CH2O);
40.81 (HNCH2CH2CH2N(CH2)4N); 53.37 (HNCH2CH2CH2N(CH2)4N);
56.02 (HNCH2CH2CH2N(CH2)4N); 67.57 (CH3CH2CH2CH2O); 113.23
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(C], C-5); 158.30 (C-40, Ar); 158.59 (C]N, C-2); 170.11 (C]O, C-4).
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requires 713.4497).
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