Synthesis and evaluation of monoamidoxime derivatives: Toward new antileishmanial compounds

Article abstract of DOI:10.1016/j.ejmech.2011.04.026

A new series of monoamidoxime derivatives was synthesized using manganese(III) acetate by microwave irradiation. Several amidoximes (27-31, 33, 38) showed valuable in vitro activities toward Leishmania donovani promastigotes, exhibiting IC₅₀ values between 5.21 and 7.89 μM. In parallel, the cytotoxicity of these compounds was evaluated on murine J774A.1 cells, revealing the corresponding selectivity index (SI). Among the 13 tested compounds, 4 monoamidoximes (27-30) exhibited an SI more than 20 times better than pentamidine. Moreover, monoamidoxime 28 (4-[5-Benzyl-3-(4- fluorophenylsulfonyl)-5-methyl-4,5-dihydrofuran-2-yl]-N′- hydroxybenzimidamide) is 40 times more selective than pentamidine, and 1.6 times more than amphotericin B, used as reference drug compounds.

Full text of DOI:10.1016/j.ejmech.2011.04.026

European Journal of Medicinal Chemistry 46 (2011) 2984e2991
Contents lists available at ScienceDirect
European Journal of Medicinal Chemistry
journal homepage: http://www.elsevier.com/locate/ejmech
Original article
Synthesis and evaluation of monoamidoxime derivatives: Toward new
antileishmanial compounds
Lucie Paloque a, Ahlem Bouhlel b, Christophe Curti b, Aurélien Dumètre a, Pierre Verhaeghe b,
,
Nadine Azas a, Patrice Vanelle b
*
a UMR-MD3-Relations Hôte-Parasites, Pharmacologie et Thérapeutique, Faculté de Pharmacie, Université d’Aix-Marseille II, 27 Boulevard Jean Moulin,
13385 Marseille Cedex 05, France
b Laboratoire de Pharmaco-Chimie Radicalaire (LPCR), Faculté de Pharmacie, Universités d’Aix-Marseille I, II, et III e CNRS, UMR 6264: Laboratoire Chimie Provence,
27 Boulevard Jean Moulin, 13385 Marseille 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 series of monoamidoxime derivatives was synthesized using manganese(III) acetate by microwave
irradiation. Several amidoximes (27e31, 33, 38) showed valuable in vitro activities toward Leishmania
donovani promastigotes, exhibiting IC50 values between 5.21 and 7.89 mM. In parallel, the cytotoxicity of
these compounds was evaluated on murine J774A.1 cells, revealing the corresponding selectivity index
(SI). Among the 13 tested compounds, 4 monoamidoximes (27e30) exhibited an SI more than 20 times
better than pentamidine. Moreover, monoamidoxime 28 (4-[5-Benzyl-3-(4-fluorophenylsulfonyl)-5-
methyl-4,5-dihydrofuran-2-yl]-N0-hydroxybenzimidamide) is 40 times more selective than pentamidine,
and 1.6 times more than amphotericin B, used as reference drug compounds.
Received 22 February 2011
Received in revised form
7 April 2011
Accepted 9 April 2011
Available online 15 April 2011
Keywords:
Manganese(III) acetate
Amidoxime
Ó 2011 Elsevier Masson SAS. All rights reserved.
Leishmania donovani
Anti-infectious
1. Introduction
Among the series of synthetic arylamidines, pafuramidine (Scheme
1) has shown interesting therapeutic activities against L. donovani
Leishmaniasis is one of the most widespread parasitic diseases. It
is transmitted by the bite of a sand-fly contaminated by a flagellate
protozoan belonging to the genus Leishmania. The disease is endemic
in 89 countries and its visceral form, caused by Leishmania donovani,
leads to 5,00,000 new cases and 50,000 deaths per year [1].
1,5-Bis(4-amidinophenoxy)pentane (pentamidine, Scheme 1) is
and offers good oral bioavailability due to the replacement of
amidines by methoxyamidoximes [12].
In the course of our ongoing work on the preparation of antipar-
asitic compounds [13], we have previously reported the synthesis of
diarylamidoxime derivatives, yielding a 2,3-dihydrofuran instead of
the furan scaffold of pafuramidine [14]. Several of these diamidoxime
derivatives exhibited good activity against L. donovani. Surprisingly,
monoamidoxime derivatives also had good activity, whereas with
amidoxime, two scaffolds appeared to be necessary for antiparasitic
potential. We present herein a complementary study in which we
synthesized various substituted monoamidoximes, in order to
confirm and further characterize this newly-observed activity.
a
well-known antiprotozoan aromatic diamidine [2]. It is
commonly used against various infections such as leishmaniasis
[3,4], trypanosomiasis [3,5] and HIV-related Pneumocystis jirovecii
opportunistic pneumonia [6]. In spite of its wide antiparasitic
spectrum, the use of pentamidine remains limited by its high
toxicity, in particular nephro-, cardio- and neurological toxicities
[2,7]. Furthermore, at physiological pH, amidine groups are salified,
decreasing membrane permeability and thus necessitating paren-
teral administration [8].
2. Results and discussion
Arylamidines are known to bind to the minor groove of AT DNA
sequences along the phosphodiester backbone [9,10]. Two amidi-
nium end groups appear to be necessary for this interaction [11]
while the central part of the drug inserts into the minor groove.
2.1. Chemistry
Several
b-ketosulfones (1e13) were synthesized using a previ-
ously reported microwave-irradiated method [15].
Sodium sulfite, sodium bicarbonate and sulfonyl chlorides in
water were irradiated at 500 W for 20 min in a microwave oven. An
ethanolic solution of the corresponding acetophenone was then
* Corresponding author. Tel.: þ33 4 91 83 55 80; fax: þ33 4 91 79 46 77.
E-mail address: patrice.vanelle@univmed.fr (P. Vanelle).
0223-5234/$ e see front matter Ó 2011 Elsevier Masson SAS. All rights reserved.
doi:10.1016/j.ejmech.2011.04.026

L. Paloque et al. / European Journal of Medicinal Chemistry 46 (2011) 2984e2991
2985
O
O
H
N
H
N
H3C
CH3
O
H2N
NH2
NH
O
O
Pentamidine
HN
NH
NH
Pafuramidine
R2
O
S
O
R4
R3
O
R1
OH
OH
N
N
N OH
NH2
R1,R2 = -H,
,
,
NH2
NH
NH2
R3/R4 = -Ph/-Ph, -CH3/Bn
Scheme 1.
added to sodium sulfinate and the reaction mixture was irradiated
for 10 min to produce sulfones in good yields (1e13) (Scheme 2).
Following a previously described procedure [16], manganese(III)
acetate was added to glacial acetic acid, and the suspension was
irradiatedinamicrowaveovenat80ꢀC for15minuntil solubilization.
The best activities were obtained for substituents carried on the
sulfone moiety with amidoxime carried on the other benzenic
moiety. Given the IC50 of monoamidoximes 32 and 39, nitro groups
seem to decrease antileishmanial activities.
To this solution,
b-ketosulfone 1e13 and (2-methylallyl)benzene
2.2.2. Cytotoxicity
were added and the mixture was irradiated (200 W) for 60 min.
The desired 2,3-dihydrofuran derivatives (14e26) were
obtained (Scheme 3) in low to good yields. Yields highly depend on
the R1 substituent on the acetophenone moiety.
Finally, 10 equivalents of hydroxylamine hydrochloride and
potassium tert-butoxide were added to previously synthesized
nitrile derivative (14e26) in DMSO (Scheme 4) [17]. Corresponding
monoamidoximes (27e39) were obtained in good yields (Table 1.).
Compared to the cytotoxicity of pentamidine (IC50 ¼ 1.03
and amphotericin B (IC50 ¼ 3.14 M), the cytotoxicity of mono-
amidoximes ranged from low to moderate (50.65e7.05 M).
For the most active compounds, cytotoxicity values of mono-
amidoximes 27e30 were low (20.07e45.53 M). Cytotoxicity
mM)
m
m
m
seems to be increased by iodo and methoxy substituents when
amidoxime is carried on the sulfone moiety.
By comparing antileishmanial activity and cytotoxicity we
determined a selectivity index. This SI is better than that of pent-
amidine (0.16) for all of our molecules. 4 monoamidoximes (27e30)
are over 20 times more selective than pentamidine (3.71e6.37), and
the most interesting monoamidoxime, 28, which bears a fluoro-
substituent on the sulfone moiety (Scheme 6), is 40 times more
selective than pentamidine and 1.6 times more than amphotericin B.
2.2. Biology
Synthesized amidoximes 27e39 were evaluated in vitro for their
activity against promastigotes of L. donovani strain MHOM/IN/00/
DEVI and for their cytotoxicity toward mouse J774A.1 macrophages
that serve as an in vitro host cell model for screening antileishmanial
drugs [18]. The results of the evaluation are summarized in Table 2.
3. Conclusion
2.2.1. Antiparasitic activity
All monoamidoxime derivatives tested exhibited antileishmanial
activity. One of them, monoamidoxime 30, showed better anti-
In conclusion, manganese(III)-assisted reactions allowed the
synthesis of a new series of monoamidoximes. Thirteen tested
products exhibited antileishmanial activity and moderate cyto-
toxicity with a better selectivity index compared to pentamidine,
used as reference.
leishmanial activity than that of pentamidine (IC50 ¼ 5.21
6.29 M). Moreover, 6 other monoamidoximes 27e29, 31, 33, 38
(Scheme 5) had antileishmanial activities close to that of pentami-
dine (IC50 between 6.29 and 7.89 M).
mM versus
m
Moreover, molecule 30, a bromo derivative, has the lowest IC50
m
against L. donovani promastigote (5.21
mM versus 6.29 mM for
Substituents such as halogen, trifluoromethyl or methoxy
pentamidine), and molecule 28, a fluoro derivative, has an inter-
groups improved antileishmanial activity on monoamidoximes.
esting activity coupled with low cytotoxicity, making it 40 times
R2
R2
R1
O
1) Na2SO3, NaHCO3,
water, 100 o
500 W, 20 min.
C
O
Mn(OAc)3, Cu(OAc)2
CH3
S
O
O
O
O
S
O
S
Br
S
CH3
AcOH, 80 o
200 W, 60 min.
C
O
R1
Cl
R2
R1
O
O
2) water, 100 oC
500 W, 10 min.
O
R1
O
R2
14-26
1-13
1-13
Scheme 2.
Scheme 3.

2986
L. Paloque et al. / European Journal of Medicinal Chemistry 46 (2011) 2984e2991
d
: 63.7 (CH2), 116.8 (d, J ¼ 22.7, 2CH),117.5 (C), 117.7 (C), 129.7 (2CH),
HO
N
131.6 (d, J ¼ 9.9, 2CH), 132.7 (2CH), 134.2 (d, J ¼ 3.3, C), 138.3 (C),
166.3 (d, J ¼ 258.3, C), 187.0 (C). Anal. Calcd for C15H10FNO3S
(303.31 g molꢂ1): C, 59.40; H, 3.32; N, 4.62. Found: C, 59.35; H, 3.35;
N, 4.59.
NH2OH, HCl (10 eq.)
NC
H2N
O
O
tBuOK (10 eq.)
CH3
CH3
O
DMSO, N2
O
S
S
5 oC to R.T.
O
O
4.1.2.3. 4-[2-(4-Chlorophenylsulfonyl)acetyl]benzonitrile (3). White
solid, mp 146e148 ꢀC (isopropyl alcohol) 1H NMR (CDCl3),
d: 4.75 (s,
27-33
14-20
R2
R2
2H, CH2), 7.54 (d, J ¼ 8.4, 2H, 2CH), 7.78e7.82 (m, 4H, 4CH), 8.06 (d,
J ¼ 8.4, 2H, 2CH). 13C NMR (CDCl3),
d: 63.5 (CH2), 117.4 (C), 117.6 (C),
129.6 (2CH),129.7 (2CH),130.0(2CH),132.6 (2CH),136.6 (C),138.3(C),
141.4 (C), 186.9 (C). Anal. Calcd for C15H10ClNO3S (319.76 g molꢂ1):
C, 56.34; H, 3.15; N, 4.38. Found: C, 55.94; H, 3.10; N, 4.30.
NH2OH, HCl (10 eq.)
tBuOK (10 eq.)
R1
R1
O
O
CH3
CH3
O
DMSO, N2
O
S
S
4.1.2.4. 4-[2-(4-Bromophenylsulfonyl)acetyl]benzonitrile (4) [14]
5 oC to R.T.
O
O
4.1.2.4.1. 4-[2-(4-Iodophenylsulfonyl)acetyl]benzonitrile
(5). White solid, mp 179 ꢀC (isopropyl alcohol) 1H NMR (CDCl3),
d:
N
NC
4.72 (s, 2H, CH2), 7.57 (d, J ¼ 8.6, 2H, 2CH), 7.82 (d, J ¼ 8.5, 2H, 2CH),
21-26
34-39
HO
NH2
7.94 (d, J ¼ 8.6, 2H, 2CH), 8.07 (d, J ¼ 8.5, 2H, 2CH). 13C NMR (CDCl3),
d: 63.6 (CH2), 102.9 (C), 117.5 (C), 117.7 (C), 129.7 (2CH), 129.8 (2CH),
Scheme 4.
132.7 (2CH), 137.8 (C), 138.3 (C), 138.7 (2CH), 186.9 (C). Anal. Calcd
more selective than pentamidine, and 1.6 times more than
amphotericin B. With a view to refining these findings, pharma-
comodulation studies are in progress, targeting substituents on
position 5 of the dihydrofuran.
Table 1
Synthesis of amidoximes from nitriles.
Compound
R1
R2
Yield (%)a
91
N OH
4. Experimental
27
C
eCF3
NH2
4.1. Chemistry
N OH
4.1.1. Instruments and analyses
28
C
eF
85
NH2
Microwave-assisted reactions were performed in a multimode
microwave oven ETHOS Synth Lab Station (Ethos start, Milestone
Inc.). Melting points were determined with a B-540 Büchi melting
point apparatus. 1H NMR (200 MHz) and 13C NMR (50 MHz)
spectra were recorded on a Bruker ARX 200 spectrometer at the
Service Interuniversitaire de RMN de la Faculté de Pharmacie de
N OH
29
30
31
32
C
eCl
79
89
83
80
NH2
N OH
C
eBr
Marseille. 1H and 13C NMR chemical shifts (
d) are reported in parts
NH2
per million with respect to CDCl3 7.26 ppm (1H) and 77 ppm (13C).
Elemental analysis was carried out at the Spectropole de la Faculté
des Sciences et Techniques de Saint-Jérôme. The following adsor-
bent was used for flash column chromatography: silica gel 60
(Merck, particle size 0.063e0.200 nm, 70e230 mesh ASTM). TLC
was performed on 5 cm ꢁ 10 cm aluminum plates coated with
silica gel 60F254 (Merck) in appropriate solvent. Mass spectra were
run on an API-QqToF mass spectrometer.
N OH
C
eI
NH2
N OH
C
eNO2
eOCH3
NH2
N OH
33
34
C
89
81
NH2
N OH
eCF3
C
4.1.2.
b-Ketosulfones synthesis
NH2
N OH
Compounds 1e13 were synthesized according to previously
described procedures [14,15].
35
36
37
38
eF
C
93
91
56
83
55
NH2
4.1.2.1. -{2-[4-(Trifluoromethyl)phenylsulfonyl]acetyl}benzonitrile
(1). White solid, mp 186e187 ꢀC (isopropyl alcohol) 1H NMR
N OH
eCl
eBr
eI
C
(CDCl3),
d
: 4.78 (s, 2H, CH2), 7.82 (d, J ¼ 8.6, 2H, 2CH), 7.87 (d, J ¼ 8.1,
NH2
2H, 2CH), 8.04 (d, J ¼ 8.1, 2H, 2CH), 8.08 (d, J ¼ 8.6, 2H, 2CH). 13C
N OH
NMR (CDCl3),
d: 63.3 (CH2), 117.4 (C), 117.8 (C), 122.9 (q, J ¼ 273.3, C),
C
126.5 (q, J ¼ 4.0, 2CH), 129.3 (2CH), 129.7 (2CH), 132.7 (2CH), 136.2
(q, J ¼ 33.3, C), 138.2 (C), 141.7 (C), 186.7 (C). Anal. Calcd for
C16H10F3NO3S (353.32 g molꢂ1): C, 54.39; H, 2.85; N, 3.96. Found:
C, 54.43; H, 2.75; N, 3.94.
NH2
N OH
C
NH2
N OH
4.1.2.2. -[2-(4-Fluorophenylsulfonyl)acetyl]benzonitrile (2). White
39
eNO2
C
solid, mp 160e161 ꢀC (isopropyl alcohol) 1H NMR (CDCl3),
d: 4.74 (s,
NH2
2H, CH2), 7.21e7.30 (m, 2H, 2CH), 7.82 (d, J ¼ 8.4, 2H, 2CH),
a
7.88e7.94 (m, 2H, 2CH), 8.08 (d, J ¼ 8.4, 2H, 2CH). 13C NMR (CDCl3),
Yield of isolated product based on the corresponding 2,3-dihydrofuran.

L. Paloque et al. / European Journal of Medicinal Chemistry 46 (2011) 2984e2991
2987
Table 2
HO
N
In vitro activity/cytotoxicity of compounds 27e39.
Compound
Leishmania donovani, Cytotoxicity J774A.1 IC50 Selectivity
H2N
promastigotes IC50
M) ꢃ SD
(
mM) ꢃ SD
Index (SI)
O
(m
CH3
27
28
29
30
31
32
33
34
35
36
37
38
7.89 ꢃ 2.23
7.15 ꢃ 2.17
7.40 ꢃ 0.13
5.21 ꢃ 0.55
6.89 ꢃ 0.47
30.52 ꢃ 2.23
45.53 ꢃ 0.28
27.43 ꢃ 4.30
20.07 ꢃ 5.24
11.84 ꢃ 2.47
50.65 ꢃ 1.16
9.03 ꢃ 2.84
11.86 ꢃ 4.59
36.19 ꢃ 13.87
7.05 ꢃ 0.37
9.78 ꢃ 0.06
8.08 ꢃ 2.10
18.46 ꢃ 8.77
1.03 ꢃ 0.40
3.14 ꢃ 0.45
0.02 ꢃ 0.01
3.87
6.37
3.71
3.85
1.72
2.61
1.21
1.40
1.18
0.71
1.09
1.22
0.98
0.16
4.08
O
S
O
19.40 ꢃ 9.74
7.49 ꢃ 1.04
8.46 ꢃ 0.30
30.67 ꢃ 11.37
9.87 ꢃ 1.43
8.95 ꢃ 0.28
6.63 ꢃ 0.31
18.83 ꢃ 1.33
6.29 ꢃ 0.07
0.77 ꢃ 0.03
28
F
IS = 6.37
IS Pentamidine = 0.16
IS Amphotericin B = 4.08
39
Pentamidine
Amphotericin B
Doxorubicin
Scheme 6.
conditions. Anal. Calcd for C15H10FNO3S (319.76 g molꢂ1): C, 59.40;
H, 3.32; N, 4.62. Found: C, 59.48; H, 3.34; N, 4.63.
for C15H10INO3S (411.21 g molꢂ1): C, 43.81; H, 2.45; N, 3.41. Found:
C, 43.60; H, 2.45; N, 3.43.
4.1.2.4.6. 4-[2-(4-Chlorophenyl)-2-oxoethylsulfonyl]benzonitrile
(10). White solid, mp 205e206 ꢀC (isopropyl alcohol) 1H NMR
4.1.2.4.2. 4-[2-(4-Nitrophenylsulfonyl)acetyl]benzonitrile
(6). Yellow solid, mp 188e190 ꢀC (isopropyl alcohol) 1H NMR
(DMSO-d6),
J ¼ 8.6, 2H, 2CH), 8.10 (d, J ¼ 8.9, 2H, 2CH), 8.15 (d, J ¼ 8.9, 2H, 2CH).
13C NMR (DMSO-d6),
: 61.9 (CH2), 116.5 (C), 117.7 (C), 129.0 (2CH),
d: 5.56 (s, 2H, CH2), 7.61 (d, J ¼ 8.6, 2H, 2CH), 7.97 (d,
(CDCl3),
d
: 4.81 (s, 2H, CH2), 7.84 (d, J ¼ 8.5, 2H, 2CH), 8.09 (d, J ¼ 8.2,
2H, 2CH), 8.11 (d, J ¼ 8.6, 2H, 2CH), 8.44 (d, J ¼ 8.6, 2H, 2CH). 13C
d
129.1 (2CH), 131.0 (2CH), 133.5 (2CH), 134.4 (C), 139.6 (C), 143.6 (C),
183.3 (C). Anal. Calcd for C15H10ClNO3S (319.76 g molꢂ1): C, 56.34;
H, 3.15; N, 4.38. Found: C, 56.24; H, 3.14; N, 4.31.
NMR (CDCl3), d: 63.2 (CH2), 117.3 (C), 118.1 (C), 124.5 (2CH), 129.6
(2CH), 130.3 (2CH), 132.8 (2CH), 138.1 (C), 143.5 (C), 151.2 (C), 186.6
(C). Anal. Calcd for C15H10N2O5S (330.32 g molꢂ1): C, 54.54; H, 3.05;
N, 8.48. Found: C, 54.16; H, 3.26; N, 8.13.
4.1.2.5. 4-[2-(4-Bromophenyl)-2-oxoethylsulfonyl]benzonitrile (11)
[14]
4.1.2.4.3. 4-[2-(4-Methoxyphenylsulfonyl)acetyl]benzonitrile
(7). White solid, mp 144e145 ꢀC (isopropyl alcohol) 1H NMR
4.1.2.5.1. 4-[2-(4-Iodophenyl)-2-oxoethylsulfonyl]benzonitrile
(CDCl3),
7.78 (d, J ¼ 9.0, 2H, 2CH), 7.80 (d, J ¼ 8.6, 2H, 2CH), 8.08 (d, J ¼ 8.6, 2H,
2CH). 13C NMR (CDCl3),
: 55.8 (CH3), 64.1 (CH2), 114.5 (2CH), 117.4
d
: 3.89(s, 3H, CH3), 4.71 (s, 2H, CH2), 7.00 (d, J ¼ 9.0, 2H, 2CH),
(12). Yellow solid, mp 218 ꢀC (isopropyl alcohol) 1H NMR (DMSO-
d6),
d
: 5.53 (s, 2H, CH2), 7.70 (d, J ¼ 8.4, 2H, CH), 7.93 (d, J ¼ 8.4, 2H,
: 61.8 (CH2), 103.8
d
CH), 8.11e8.13 (m, 4H, CH). 13C NMR (DMSO-d6),
d
(C), 117.6 (C), 129.7 (C), 129.8 (2CH), 130.8 (2CH), 132.6 (2CH), 138.5
(C),164.4 (C),187.3 (C). Anal. Calcd for C16H13NO4S (315.34 g molꢂ1):
C, 60.94; H, 4.16; N, 4.44. Found: C, 60.80; H, 4.15; N, 5.04.
(C), 116.5 (C), 117.7 (C), 129.0 (2CH), 130.7 (2CH), 133.4 (2CH), 134.9
(C), 137.9 (2CH), 143.5 (C), 188.9 (C). Anal. Calcd for C15H10INO3S
(411.21 g molꢂ1): C, 43.81; H, 2.45; N, 3.41. Found: C, 44.21; H, 2.43;
N, 3.57.
4.1.2.4.4. 4-{2-oxo-2-[4-(Trifluoromethyl)phenyl]ethylsulfonyl}
benzonitrile (8). White solid, mp 160e162 ꢀC (isopropyl alcohol) 1H
4.1.2.5.2. 4-[2-(4-Nitrophenyl)-2-oxoethylsulfonyl]benzonitrile
NMR (DMSO-d6),
d
: 5.65 (s, 2H, CH2), 7.91 (d, J ¼ 8.3, 2H, 2CH),
(13). Yellow solid, mp 175e176 ꢀC (isopropyl alcohol) 1H NMR
8.09e8.17 (m, 6H, 6CH). 13C NMR (DMSO-d6),
d
: 62.2 (CH2), 116.6
(DMSO-d6), d: 5.66 (s, 2H, CH2), 8.09e8.19 (m, 4H, 4CH), 8.17 (d,
(C), 117.7 (C), 123.8 (q, J ¼ 273.0, C), 125.9 (q, J ¼ 3.7, 2CH), 129.1
J ¼ 8.9, 2H, 2CH), 8.33 (d, J ¼ 8.9, 2H, 2CH). 13C NMR (DMSO-d6),
d:
(2CH),129.9 (2CH),133.5 (2CH),133.6 (q, J ¼ 32.2, C),138.7 (C),143.4
þ
62.4 (CH2), 116.7 (C), 117.7 (C), 124.0 (2CH), 129.1 (2CH), 130.6 (2CH),
133.6 (2CH), 140.1 (C), 143.4 (C), 150.7 (C), 188.7 (C). Anal. Calcd for
C15H10N2O5S (330.32 g molꢂ1): C, 54.54; H, 3.05; N, 8.48. Found:
C, 54.58; H, 3.06; N, 8.38.
(C), 188.9 (C). HMRS (EI): m/z calcd for C16H10F3NO3S M þ NH4
371.0672. Found: 371.0664.
:
4.1.2.4.5. 4-[2-(4-Fluorophenyl)-2-oxoethylsulfonyl]benzonitrile
(9). White solid, mp 168 ꢀC (ethyl alcohol) 1H NMR (DMSO-d6),
d
: 5.56 (s, 2H, CH2), 7.37 (t, J ¼ 8.8, 2H, CH), 8.02e8.18 (m, 6H, CH).
13C NMR (DMSO-d6),
d
: 61.9 (CH2), 115.9 (CH), 116.4 (d, J ¼ 22.0,
4.1.3. General procedure for Mn(OAc)3-mediated reaction of
ketosulfones with alkenes
b-
2CH), 117.7 (C), 129.0 (2CH), 132.3 (d, J ¼ 9.9, 2CH), 133.4 (2CH),
143.6 (C),165.9 (d, J ¼ 253.9, C),187.2 (C).1 (C) not observed in these
A solution of manganese(III) acetate dihydrate (6.87 mmol,
1.84 g) and copper(II) acetate (3.27 mmol, 0.59 g) in 30 mL of glacial
acetic acid was heated under microwave irradiation (200 W, 80 ꢀC)
for 15 min, until dissolution. Then, the reaction mixture was cooled
to 50 ꢀC, and a solution of 1e5 (3.27 mmol) and 1.1-diphenylethene
(9.81 mmol) in 5 mL acetic acid was added. The mixture was heated
under microwave irradiation (200 W, 80 ꢀC) for 45 min. The reac-
tion mixture was poured into 200 mL of cold water, and extracted
with chloroform (3 ꢁ 40 mL). The organic extracts were collected
and washed with saturated aqueous NaHCO3 (3 ꢁ 40 mL) and dried
(MgSO4). Solvent evaporation was followed by column chroma-
tography (gradient, from chloroform/petroleum ether (1/1) to
chloroform/petroleum ether/diethyl ether (5/3/2)), and the product
obtained was recrystallized from the appropriate solvent.
HO
N
I
H2N
O
O
CH3
CH3
O
O
S
S
27, R = -CF3
28, R = -F
O
O
38
29, R = -Cl
30, R = -Br
31, R = -I
R
H2N
N
HO
33, R = -OCH3
Scheme 5.

2988
L. Paloque et al. / European Journal of Medicinal Chemistry 46 (2011) 2984e2991
4.1.3.1. 4-{5-Benzyl-5-methyl-3-[4-(trifluoromethyl)phenylsulfonyl]-
4,5-dihydrofuran-2-yl}benzonitrile (14). White solid, mp 152e153 ꢀC
129.0 (2CH), 130.1 (2CH), 130.3 (2CH), 131.4 (2CH), 132.8 (C), 133.2
(C), 135.4 (C), 159.2 (C), 163.1 (C). Anal. Calcd for C26H23NO4S
(445.53 g molꢂ1): C, 70.09; H, 5.20; N, 3.14. Found: C, 69.76; H, 5.43;
N, 3.52.
(isopropyl alcohol) 1H NMR (CDCl3),
d: 1.54 (s, 3H, CH3), 2.78e3.08
(m, 4H, 2CH2), 7.02e7.07 (m, 2H, 2CH), 7.13e7.20 (m, 3H, 3CH), 7.56
(d, J ¼ 8.4, 2H, 2CH), 7.64e7.69 (m, 6H, 6CH). 13C NMR (CDCl3),
d
: 27.7
4.1.3.4.4. 4-{5-Benzyl-5-methyl-2-[4-(trifluoromethyl) phenyl]-
4,5-dihydrofuran-3-ylsulfonyl}benzonitrile (21). White solid, mp
(CH3), 41.2 (CH2), 46.4 (CH2), 89.3 (C), 110.7 (C), 114.6 (C), 118.0 (C),
123.1 (q, J ¼ 273.0, C), 126.2 (q, J ¼ 3.7, 2CH), 127.1 (CH), 127.2 (2CH),
128.3 (2CH),130.0 (2CH), 130.2 (2CH), 131.6 (2CH),132.8 (C),134.5 (q,
J ¼ 32.9, C), 135.1 (C), 144.6 (C), 161.6 (C). Anal. Calcd for
C26H20F3NO3S (483.50 g molꢂ1): C, 64.59; H, 4.17; N, 2.90. Found: C,
64.53; H, 4.37; N, 2.89.
198e200 ꢀC (isopropyl alcohol) 1H NMR (CDCl3),
d: 1.55 (s, 3H, CH3),
2.80e3.11 (m, 4H, 2CH2), 7.08e7.12 (m, 2H, 2CH), 7.18e7.24 (m, 3H,
3CH), 7.50 (d, J ¼ 8.1, 2H, 2CH), 7.62e7.66 (m, 6H, 6CH). 13C NMR
(CDCl3), d: 27.1 (CH3), 41.2 (CH2), 46.4 (CH2), 89.2 (C), 109.7 (C),116.4
(C),117.2 (C), 123.6 (q, J ¼ 273.0, C),124.9 (q, J ¼ 3.7, 2CH),127.1 (CH),
127.2 (2CH), 128.3 (2CH), 129.7 (2CH), 130.3 (2CH), 131.8 (C), 132.7
(2CH), 135.3 (C), 145.5 (C), 162.9 (C). 1 (C) not observed in these
conditions. HMRS (EI): m/z calcd for C26H20F3NO3S M þ Hþ:
484.1189. Found: 484.1189.
4.1.3.2. 4-[5-Benzyl-3-(4-fluorophenylsulfonyl)-5-methyl-4,5-dihy-
drofuran-2-yl]benzonitrile (15). Yellow solid, mp 147e148 ꢀC (iso-
propyl alcohol) 1H NMR (CDCl3),
d
: 1.51 (s, 3H, CH3), 2.81e3.07 (m,
4H, 2CH2), 7.03e7.11 (m, 4H, 4CH), 7.20e7.24 (m, 2H, 2CH),
7.45e7.52 (m, 3H, 3CH), 7.67e7.72 (m, 4H, 4CH). 13C NMR (CDCl3),
4.1.3.4.5. 4-[5-Benzyl-2-(4-fluorophenyl)-5-methyl-4,5-dihy-
d:
drofuran-3-ylsulfonyl]benzonitrile (22). Yellow oil 1H NMR (CDCl3),
d:
27.4 (CH3), 41.6 (CH2), 46.4 (CH2), 89.0 (C), 111.6 (C), 114.3 (C), 116.3
(d, J ¼ 22.7, 2CH), 118.1 (C), 127.1 (CH), 128.3 (2CH), 129.5 (d, J ¼ 9.5,
2CH), 130.0 (2CH), 130.3 (2CH), 131.5 (2CH), 133.0 (C), 135.3 (C),
137.3 (d, J ¼ 3.3, C), 160.4 (C), 165.2 (d, J ¼ 255.8, C). Anal. Calcd for
C25H20FNO3S (433.49 g molꢂ1): C, 69.27; H, 4.65; N, 3.23. Found:
C, 68.96; H, 4.77; N, 3.19.
1.52 (s, 3H, CH3), 2.83 (d, J ¼ 14.0, 1H, CH2), 2.88 (d, J ¼ 14.5, 1H, CH2),
3.05 (d, J ¼ 14.5, 1H, CH2), 3.06 (d, J ¼ 14.0, 1H, CH2), 7.03e7.13 (m, 4H,
4CH), 7.19e7.25 (m, 3H, 3CH), 7.47 (d, J ¼ 8.4, 2H, 2CH), 7.54e7.64 (d,
4H, 4CH). 13C NMR (CDCl3),
d: 27.6 (CH3), 41.3 (CH2), 46.4 (CH2), 88.6
(C), 108.2 (C), 115.2 (d, J ¼ 22.0, 2CH), 116.1 (C), 117.3 (C), 124.3 (d,
J ¼ 3.3, C), 127.0 (3CH), 128.3 (2CH), 130.4 (2CH), 131.6 (d, J ¼ 8.8,
2CH), 132.6 (2CH), 135.4 (C), 145.9 (C), 163,5 (C), 164.3 (d, J ¼ 252.9,
C). HMRS (EI): m/z calcd for C25H20FNO3S M þ Hþ: 434.1221. Found:
434.1225.
4.1.3.3. 4-[5-Benzyl-3-(4-chlorophenylsulfonyl)-5-methyl-4,5-dihy-
drofuran-2-yl]benzonitrile (16). White solid, mp 144e146 ꢀC (iso-
1
propyl alcohol) H NMR (CDCl3),
d: 1.52 (s, 3H, CH3), 2.79e3.06 (m,
4.1.3.4.6. 4-[5-Benzyl-2-(4-chlorophenyl)-5-methyl-4,5-dihy-
4H, 2CH2), 7.04e7.08 (m, 2H, 2CH), 7.20e7.23 (m, 3H, 3CH), 7.35 (d,
drofuran-3-ylsulfonyl]benzonitrile (23). Yellow oil, 1H NMR (CDCl3),
d:
J ¼ 8.8, 2H, 2CH), 7.40 (d, J ¼ 8.8, 2H, 2CH), 7.64e7.72 (m, 4H, 4CH).13C
1.52 (s, 3H, CH3), 2.79e3.10 (m, 4H, 2CH2), 7.07e7.12 (m, 2H, 2CH),
7.20e7.25 (m, 2H, 2CH), 7.29e7.41 (m, 3H, 3CH), 7.46e7.54 (m, 4H,
NMR (CDCl3), d: 27.5 (CH3), 41.5 (CH2), 46.4 (CH2), 89.1 (C), 111.3 (C),
114.4 (C), 118.1 (C), 127.1 (CH), 128.1 (2CH), 128.3 (2CH), 129.3 (2CH),
130.1 (2CH), 130.2 (2CH), 131.5 (2CH), 132.9 (C), 135.2 (C), 139.5 (C),
139.7 (C),160.7 (C). Anal. Calcd for C25H20ClNO3S (449.95 g molꢂ1): C,
66.73; H, 4.48; N, 3.11. Found: C, 66.51; H, 4.67; N, 3.02.
4CH), 7.63 (d, J ¼ 8.4, 2H, 2CH). 13C NMR (CDCl3),
d: 27.6 (CH3), 41.4
(CH2), 46.4 (CH2), 88.7 (2C), 108.6 (C), 116.2 (C), 117.3 (C), 126.6 (CH),
127.0 (C), 127.1 (2CH), 128.3 (2CH), 130.4 (2CH), 130.6 (2CH), 131.6
(2CH), 132.7 (2CH), 135.4 (C), 145.9 (C), 163.4 (C). HMRS (EI): m/z
calcd for C25H20ClNO3S M þ Hþ: 450.0925. Found: 450.0917.
4.1.3.4. 4-[5-Benzyl-3-(4-bromophenylsulfonyl)-5-methyl-4,5-dihy-
drofuran-2-yl]benzonitrile (17) [14]
4.1.3.5. 4-[5-Benzyl-2-(4-bromophenyl)-5-methyl-4,5-dihydrofu–
ran-3-ylsulfonyl]benzonitrile (24) [14]
4.1.3.4.1. 4-[5-Benzyl-3-(4-iodophenylsulfonyl)-5-methyl-4,5-
dihydrofuran-2-yl]benzonitrile (18). White solid, mp 176e177 ꢀC
4.1.3.5.1. 4-[5-Benzyl-2-(4-iodophenyl)-5-methyl-4,5-dihy-
(isopropyl alcohol) 1H NMR (CDCl3),
d: 1.52 (s, 3H, CH3), 2.79e3.06
drofuran-3-ylsulfonyl]benzonitrile (25). Yellow solid, mp 72 ꢀC
(m, 4H, 2CH2), 7.02e7.07 (m, 2H, 2CH), 7.15e7.26 (m, 5H, 5CH),
(isopropyl alcohol) 1H NMR (CDCl3),
d: 1.51 (s, 3H, CH3), 2.81 (d,
7.64e7.72 (m, 4H, 4CH), 7.75 (d, J ¼ 8.6, 2H, 2CH). 13C NMR (CDCl3),
J ¼ 14.0, 1H, CH2), 2.86 (d, J ¼ 14.6, 1H, CH2), 3.01 (d, J ¼ 14.6, 1H,
CH2), 3.05 (d, J ¼ 14.0, 1H, CH2), 7.06e7.11 (m, 2H, 2CH), 7.20e7.30
(m, 5H, 5CH), 7.48 (d, J ¼ 8.5, 2H, 2CH), 7.63 (d, J ¼ 8.5, 2H, 2CH), 7.74
d: 27.5 (CH3), 41.4 (CH2), 46.4 (CH2), 89.1 (C), 100.5 (C), 111.2 (C),
114.4 (C), 118.1 (C), 127.1 (CH), 128.1 (2CH), 128.3 (2CH), 130.1 (2CH),
130.2 (2CH), 131.5 (2CH), 132.9 (C), 135.2 (C), 138.3 (2CH), 140.8 (C),
160.7 (C). Anal. Calcd for C25H20INO3S (541.40 g molꢂ1): C, 55.46;
H, 3.72; N, 2.59. Found: C, 55.18; H, 3.85; N, 2.53.
(d, J ¼ 8.5, 2H, 2CH). 13C NMR (CDCl3),
d: 27.6 (CH3), 41.3 (CH2), 46.4
(CH2), 88.8 (C), 98.1 (C), 108.6 (C), 116.1 (C), 117.3 (C), 127.0 (CH),
127.1 (2CH), 127.7 (C), 128.2 (2CH), 130.3 (2CH), 130.7 (2CH), 132.7
(2CH), 135.3 (C), 137.1 (2CH), 145.7 (C), 163.5 (C). HMRS (EI): m/z
calcd for C25H20INO3S M þ Hþ: 542.0281. Found: 542.79.
4.1.3.4.2. 4-[5-Benzyl-5-methyl-3-(4-nitrophenylsulfonyl)-4,5-
dihydrofuran-2-yl]benzonitrile (19). Yellow solid, mp 189e190 ꢀC
(isopropyl alcohol) 1H NMR (CDCl3),
d: 1.55 (s, 3H, CH3), 2.78e3.11 (m,
4.1.3.5.2. 134-[5-Benzyl-5-methyl-2-(4-nitrophenyl)-4,5-dihy-
drofuran-3-ylsulfonyl]benzonitrile (26). Yellow oil 1H NMR (DMSO-
4H, 2CH2), 7.05e7.21 (m, 5H, 5CH), 7.57 (d, J ¼ 8.9, 2H, 2CH), 7.66 (d,
J ¼ 8.8, 2H, 2CH), 7.72 (d, J ¼ 8.8, 2H, 2CH), 8.20 (d, J ¼ 8.9, 2H, 2CH).
d6), d: 1.49 (s, 3H, CH3), 2.80e3.04 (m, 4H, 2CH2), 7.14e7.27 (m, 5H,
13C NMR (CDCl3),
d: 27.8 (CH3), 41.1 (CH2), 46.4 (CH2), 89.5 (C), 110.1
5CH), 7.62e7.74 (m, 4H, 4CH), 8.02 (d, J ¼ 8.0, 2H, 2CH), 8.30 (d,
(C), 114.7 (C), 117.9 (C), 124.3 (2CH), 127.1 (CH), 127.8 (2CH), 128.3
(2CH),130.0 (2CH),130.3 (2CH),131.6 (2CH),132.5 (C),135.1 (C),146.7
(C),150.0 (C),162.3 (C). Anal. Calcd for C25H20N2O5S (460.50 g molꢂ1):
C, 65.20; H, 4.38; N, 6.08. Found: C, 65.46; H, 4.47; N, 5.77.
J ¼ 8.0, 2H, 2CH). 13C NMR (DMSO-d6),
d: 25.6 (CH3), 41.8 (CH2), 45.5
(CH2), 90.1 (C), 110.6 (C), 115.8 (C), 117.7 (C), 123.3 (2CH), 126.9 (CH),
127.3 (2CH), 128.1 (2CH), 128.3 (C), 130.4 (2CH), 130.7 (2CH), 133.8
(2CH), 135.7 (C), 144.7 (C), 148.8 (C), 161.5 (C). HMRS (EI): m/z calcd
for C25H20N2O5S M þ Hþ: 461.1166. Found: 461.1161.
4.1.3.4.3. 4-[5-Benzyl-3-(4-methoxyphenylsulfonyl)-5-methyl-
4,5-dihydrofuran-2-yl]benzonitrile
(20). Yellow
solid,
mp
155e156 ꢀC (isopropyl alcohol) 1H NMR (CDCl3),
d
: 1.47 (s, 3H, CH3),
4.1.4. General procedure for amidoxime synthesis from nitriles
A suspension of hydroxylamine hydrochloride (1.7 mmol, 0.12 g,
10 eq.) in 8 mL of DMSO was stirred under inert atmosphere and
cooled to 5 ꢀC. Then, potassium tertiobutylate (1.7 mmol, 0.19 g,
10 eq.) was slowly added. The reaction mixture was stirred at room
temperature for 30 min, and the corresponding nitrile (0.17 mmol,
2.79e3.08 (m, 4H, 2CH2), 3.86 (s, 3H, CH3), 6.87 (d, J ¼ 8.9, 2H, 2CH),
7.04e7.11 (m, 2H, 2CH), 7.18e7.23 (m, 3H, 3CH), 7.46 (d, J ¼ 8.9, 2H,
2CH), 7.66 (d, J ¼ 8.8, 2H, 2CH), 7.71 (d, J ¼ 8.8, 2H, 2CH). 13C NMR
(CDCl3), d: 27.0 (CH3), 41.9 (CH2), 46.4 (CH2), 55.6 (CH3), 88.7 (C),
112.5 (C), 114.1 (C), 114.2 (2CH), 118.2 (C), 127.0 (CH), 128.3 (2CH),

L. Paloque et al. / European Journal of Medicinal Chemistry 46 (2011) 2984e2991
2989
1 eq.) was added. The reaction mixture was stirred for 12 h and
poured into 100 mL of cold water. The precipitate thus formed was
crystallized from the appropriate solvent.
167e168 ꢀC (ethyl alcohol/water, (1/1)) 1H NMR (DMSO-d6),
d: 1.46
(s, 3H, CH3), 2.82e3.05 (m, 4H, 2CH2), 5.95 (bs, 2H), 7.14e7.18 (m,
5H, 5CH), 7.48 (d, J ¼ 8.3, 2H, 2CH), 7.70e7.76 (m, 4H, 4CH), 8.31 (d,
J ¼ 8.8, 2H, 2CH), 9.86 (bs, 1H). 13C NMR (DMSO-d6),
d: 27.0 (CH3),
4.1.4.1. 4-{5-Benzyl-5-methyl-3-[4-(trifluoromethyl)phenylsulfon-
yl]-4,5-dihydrofuran-2-yl}-N0-hydroxy-benzimidamide (27). White
solid, mp 73e76 ꢀC (ethyl alcohol/water, (1/1)) 1H NMR (DMSO-
35.9 (CH2), 45.5 (CH2), 89.2 (C), 108.2 (C), 124.9 (2CH), 125.0 (2CH),
126.8 (CH), 128.0 (2CH), 128.1 (2CH), 128.6 (C), 129.0 (2CH), 130.4
(2CH), 135.8 (C), 135.9 (C), 146.7 (C), 150.0 (C), 150.4 (C), 163.7 (C).
HMRS (EI): m/z calcd for C25H23N3O6S M þ Hþ: 494.1380. Found:
494.1378.
d6), d: 2.54 (s, 3H, CH3), 2.80e3.03 (m, 4H, 2CH2), 5.93 (bs, 2H),
7.07e7.17 (m, 5H, 5CH), 7.47 (d, J ¼ 8.4, 2H, 2CH), 7.67 (d, J ¼ 8.3,
2H, 2CH), 7.73 (d, J ¼ 8.4, 2H, 2CH), 7.90 (d, J ¼ 8.3, 2H, 2CH), 9.86
(bs, 1H). 13C NMR (DMSO-d6),
d
: 27.1 (CH3), 40.8 (CH2), 45.4 (CH2),
4.1.4.7. 4-[5-Benzyl-3-(4-methoxyphenylsulfonyl)-5-methyl-4,5-
89.0 (C), 108.5 (C), 123.6 (q, J ¼ 273.0, C), 124.9 (2CH), 126.7 (CH),
126.8 (2CH), 127.4 (2CH), 128.1 (2CH), 128.7 (C), 129.0 (2CH), 130.4
(2CH), 132.8 (q, J ¼ 32.2, C), 135.8 (C), 135.9 (C), 145.2 (C), 150.3 (C),
163.2 (C). HMRS (EI): m/z calcd for C26H23F3N2O4S M þ Hþ:
517.1403. Found: 517.1400.
dihydrofuran-2-yl]-N’-hydroxybenzimi–damide (33). White solid,
mp 79e83 ꢀC (ethyl alcohol/water, (1/1)) 1H NMR (DMSO-d6),
d:
1.40 (s, 3H, CH3), 2.71e2.99 (m, 4H, 2CH2), 3.84 (s, 3H, CH3), 5.92
(bs, 2H), 7.03 (d, J ¼ 8.9, 2H, 2CH), 7.09e7.23 (m, 5H, 5CH), 7.45 (d,
J ¼ 8.9, 2H, 2CH), 7.50 (d, J ¼ 8.6, 2H, 2CH), 7.71 (d, J ¼ 8.6, 2H, 2CH),
9.84 (bs, 1H). 13C NMR (DMSO-d6),
d: 26.7 (CH3), 41.7 (CH2), 45.4
4.1.4.2. 4-[5-Benzyl-3-(4-fluorophenylsulfonyl)-5-methyl-4,5-dihy-
drofuran-2-yl]-N’-hydroxybenzimi-damide (28). White solid, mp
(CH2), 55.9 (CH3), 88.2 (C), 110.3 (C), 114.7 (2CH), 124.8 (2CH), 126.8
(CH), 128.2 (2CH), 128.7 (2CH), 129.0 (2CH), 129.1 (C), 130.5 (2CH),
133.2 (C), 135.5 (C), 136.1 (C), 150.4 (C), 160.8 (C), 162.8 (C). HMRS
(EI): m/z calcd for C26H26N2O5S M þ Hþ: 479.1635. Found: 479.1632.
139e140 ꢀC (ethyl alcohol/water, (1/1)) 1H NMR (DMSO-d6),
d: 1.40
(s, 3H, CH3), 2.73e2.98 (m, 4H, 2CH2), 5.87 (bs, 2H), 7.07e7.19 (m,
5H, 5CH), 7.26e7.35 (m, 2H, 2CH), 7.44 (d, J ¼ 8.6, 2H, 2CH),
7.49e7.53 (m, 2H, 2CH), 7.69 (d, J ¼ 8.4, 2H, 2CH), 9.80 (bs, 1H). 13C
4.1.4.8. 4-{5-Benzyl-5-methyl-2-[4-(trifluoromethyl)phenyl]-4,5-
dihydrofuran-3-ylsulfonyl}-N0-hydroxy-benzimidamide (34). White
NMR (DMSO-d6), d: 26.9 (CH3), 41.4 (CH2), 45.5 (CH2), 88.5 (C),109.4
(C), 116.7 (d, J ¼ 22.7, 2CH), 124.9 (2CH), 126.8 (CH), 128.2 (2CH),
128.8 (C), 129.0 (2CH), 129.5 (d, J ¼ 9.9, 2CH), 130.5 (2CH), 135.6 (C),
136.0 (C), 137.9 (d, J ¼ 2.9, C), 150.3 (C), 162.0 (C), 165.0 (d, J ¼ 251.8,
C). HMRS (EI): m/z calcd for C25H23FN2O4S M þ Hþ: 467.1435.
Found: 467.1434.
solid, mp 92 ꢀC (ethyl alcohol/water, (1/1)) 1H NMR (DMSO-d6),
d:
1.45 (s, 3H, CH3), 2.85e3.01 (m, 4H, 2CH2), 6.00 (bs, 2H), 7.09e7.19
(m, 5H, 5CH), 7.48e7.52 (m, 2H, 2CH), 7.65e7.69 (m, 2H, 2CH),
7.81e7.85 (m, 4H, 4CH), 10.00 (s, 1H) 13C NMR (DMSO-d6),
d: 27.0
(CH3), 41.2 (CH2), 45.5 (CH2), 89.4 (C), 110.9 (C), 125.2 (q, J ¼ 3.7,
2CH), 126.4 (2CH), 126.5 (2CH), 126.9 (CH), 128.2 (2CH), 129.5 (q,
J ¼ 272.6, C), 130.2 (2CH), 130.5 (2CH), 130.8 (q, J ¼ 31.5, C),132.8 (C),
135.9 (C), 137.9 (C), 141.0 (C), 149.9 (C), 160.8 (CH). HMRS (EI): m/z
calcd for C26H23F3N2O4S M þ Hþ: 517.1403. Found: 517.1392.
4.1.4.3. 4-[5-Benzyl-3-(4-chlorophenylsulfonyl)-5-methyl-4,5-dihydrof-
uran-2-yl]-N0-hydroxybenzimi-damide (29). White solid, mp 89e91 ꢀC
(ethyl alcohol/water, (1/1)) 1H NMR (DMSO-d6),
d: 1.44 (s, 3H, CH3),
2.84e3.01 (m, 4H, 2CH2), 5.91 (bs, 2H), 7.12e7.22 (m, 5H, 5CH),
7.46e7.49 (m, 4H, 4CH), 7.59 (d, J ¼ 8.7, 2H, 2CH), 7.73 (d, J ¼ 8.4, 2H,
4.1.4.9. 4-[5-Benzyl-2-(4-fluorophenyl)-5-methyl-4,5-dihydrofuran-
3-ylsulfonyl]-N0-hydroxybenzimi-damide (35). White solid, mp
2CH), 9.84 (bs, 1H). 13C NMR (DMSO-d6),
d: 27.0 (CH3), 41.3 (CH2), 45.4
(CH2), 88.7 (C), 109.1 (C), 124.9 (2CH), 126.8 (CH), 128.1 (2CH), 128.3
(2CH), 128.8 (C), 129.0 (2CH), 129.7 (2CH), 130.4 (2CH), 135.7 (C), 136.0
(C), 138.1 (C), 140.3 (C), 150.3 (C), 162.3 (C). HMRS (EI): m/z calcd for
C25H23ClN2O4S M þ Hþ: 483.1140. Found: 483.1143.
88 ꢀC (ethyl alcohol/water, (1/1)) 1H NMR (DMSO-d6),
d: 1.42 (s, 3H,
CH3), 2.75e3.00 (m, 4H, 2CH2), 5.98 (bs, 2H), 7.11e7.27 (m, 7H,
7CH), 7.44e7.51 (m, 4H, 4CH), 7.79 (d, J ¼ 7.8, 2H, 2CH),10.02 (s, 1H).
13C NMR (DMSO-d6),
d: 26.9 (CH3), 41.4 (CH2), 45.5 (CH2), 88.6 (C),
109.4 (C), 115.3 (d, J ¼ 22.3, 2CH), 126.2 (d, J ¼ 3.3, C), 126.3 (2CH),
126.4 (2CH), 126.9 (CH), 128.2 (2CH), 130.5 (2CH), 131.8 (d, J ¼ 8.8,
2CH), 134.0 (C), 137.7 (C), 141.4 (C), 149.9 (C), 161.3 (C), 163.5 (d,
J ¼ 249.0, C). HMRS (EI): m/z calcd for C25H23FN2O4S M þ Hþ:
467.1435. Found: 467.1436.
4.1.4.4. 4-[5-Benzyl-3-(4-bromophenylsulfonyl)-5-methyl-4,5-dihy-
drofuran-2-yl]-N0-hydroxybenzimi-damide (30). White solid, mp
93e95 ꢀC (ethyl alcohol/water, (1/1)) 1H NMR (DMSO-d6),
d: 1.44 (s,
3H, CH3), 2.77e3.03 (m, 4H, 2CH2), 5.91 (bs, 2H), 7.11e7.22 (m, 5H,
5CH), 7.38e7.50 (m, 4H, 4CH), 7.71e7.73 (m, 4H, 4CH), 9.83 (bs, 1H).
13C NMR (DMSO-d6),
d: 27.0 (CH3), 41.2 (CH2), 45.4 (CH2), 88.7 (C),
4.1.4.10. 4-[5-Benzyl-2-(4-chlorophenyl)-5-methyl-4,5-dihydrofuran-
109.0 (C), 124.9 (2CH), 126.8 (CH), 127.2 (C), 128.1 (2CH), 128.4
(2CH), 128.8 (C), 129.0 (2CH), 130.4 (2CH), 132.6 (2CH), 135.7 (C),
135.9 (C), 140.7 (C), 150.3 (C), 162.4 (C). HMRS (EI): m/z calcd for
C25H23BrN2O4S M þ Hþ: 527.0635. Found: 527.0643.
3-ylsulfonyl]-N’-hydroxybenzimi-damide (36). White solid, mp
56e58 ꢀC (ethyl alcohol/water, (1/1)) 1H NMR (DMSO-d6),
d: 1.38 (s,
3H, CH3), 2.71e2.96 (m, 4H, 2CH2), 5.92 (bs, 2H), 7.03e7.14 (m, 5H,
5CH), 7.40e7.50 (m, 4H, 4CH), 7.68e7.82 (m, 4H, 4CH), 9.99 (s, 1H).
13C NMR (DMSO-d6),
d: 27.1 (CH3), 41.5 (CH2), 45.6 (CH2), 89.1 (C),
4.1.4.5. 4-[5-Benzyl-3-(4-iodophenylsulfonyl)-5-methyl-4,5-dihy-
109.9 (C), 125.8 (C), 126.5 (2CH), 126.6 (2CH), 126.7 (CH), 127.1
(C),128.4 (2CH),128.5 (2CH),130.6 (2CH),131.2 (2CH),136.1 (C),137.9
(C), 141.4 (C), 150.1 (C), 161.4 (C). HMRS (EI): m/z calcd for
C25H23ClN2O4S M þ Hþ: 483.1140. Found: 483.1134.
drofuran-2-yl]-N’-hydroxybenzimi-damide (31). White solid, mp
68e70 ꢀC (ethyl alcohol/water, (1/1)) 1H NMR (DMSO-d6),
d: 1.44 (s,
3H, CH3), 2.75e3.02 (m, 4H, 2CH2), 5.90 (bs, 2H), 7.08e7.26 (m, 7H,
7CH), 7.48 (d, J ¼ 8.4, 2H, 2CH), 7.72 (d, J ¼ 8.4, 2H, 2CH), 7.91 (d,
J ¼ 8.5, 2H, 2CH), 9.83 (bs, 1H). 13C NMR (DMSO-d6),
d
: 26.9 (CH3),
4.1.4.11. 4-[5-Benzyl-2-(4-bromophenyl)-5-methyl-4,5-dihydrofuran-
41.6 (CH2), 45.4 (CH2), 88.6 (C),101.7 (C),109.0 (C),124.9 (2CH),126.8
(CH), 128.0 (2CH), 128.1 (2CH), 128.8 (C), 129.0 (2CH), 130.4 (2CH),
135.7 (C), 135.9 (C), 138.4 (2CH), 141.1 (C), 150.3 (C), 162.4 (C). HMRS
(EI): m/z calcd for C25H23IN2O4S M þ Hþ: 575.0496. Found: 575.0492.
3-ylsulfonyl]-N0-hydroxyben–zimidamide (37). White solid, mp
107 ꢀC (ethyl alcohol/water, (1/1)) 1H NMR (DMSO-d6),
d: 1.43 (s, 3H,
CH3), 2.75e3.01 (m, 4H, 2CH2), 5.99 (bs, 2H), 7.10e7.17 (m, 5H, 5CH),
7.41e7.51 (m, 4H, 4CH), 7.64e7.68 (m, 2H, 2CH), 7.80e7.84 (m, 2H,
2CH), 10.00 (s, 1H). 13C NMR (DMSO-d6),
d: 26.8 (CH3), 41.4 (CH2),
4.1.4.6. 4-[5-Benzyl-5-methyl-3-(4-nitrophenylsulfonyl)-4,5-dihy-
drofuran-2-yl]-N0-hydroxybenzimi-damide (32). White solid, mp
45.4 (CH2), 88.8 (C), 109.8 (C), 124.6 (C), 126.3 (2CH), 126.4 (2CH),
126.8 (CH), 127.9 (C), 128.2 (2CH), 130.4 (2CH), 131.1 (2CH), 131.2

2990
L. Paloque et al. / European Journal of Medicinal Chemistry 46 (2011) 2984e2991
(2CH),135.9 (C),137.8 (C),141.2 (C), 149.8 (C),161.1 (C). HMRS (EI): m/
z calcd for C25H23BrN2O4S M þ Hþ: 527.0635. Found: 527.0632.
France) promastigotes were assessed by MTT assay Briefly, pro-
mastigotes in late log-phase in Schneider’s medium supplemented
with 20% FCS, 2 mM
L-glutamine and antibiotics (100 U/mL peni-
4.1.4.12. 4-[5-Benzyl-2-(4-iodophenyl)-5-methyl-4,5-dihydrofuran-
cillin and 100 g/mL streptomycin) were incubated at an average
m
3-ylsulfonyl]-N0-hydroxybenzimi-damide (38). White solid, mp
density of 106 parasites/mL in sterile 96-well plates with various
concentrations of compounds dissolved in DMSO (final concen-
tration less than 0.5% v/v) incorporated in duplicate. Appropriate
controls treated by DMSO, pentamidine or amphotericin B (refer-
ence drugs) were added to each set of experiments. After a 72-h
incubation period at 27 ꢀC, parasite metabolic activity was deter-
mined. Plates were centrifuged at 900 G for 10 min and the
supernatant removed. After the addition of MTT (0.5 mg/mL in
102 ꢀC (ethyl alcohol/water, (1/1)) 1H NMR (DMSO-d6),
d: 1.42 (s,
3H, CH3), 2.74e2.99 (m, 4H, 2CH2), 5.99 (bs, 2H), 7.09e7.28 (m, 7H,
7CH), 7.48 (d, J ¼ 8.2, 2H, 2CH), 7.80e7.84 (m, 4H, 4CH), 10.02 (s,
1H). 13C NMR (DMSO-d6),
d: 26.9 (CH3), 41.4 (CH2), 45.5 (CH2), 88.9
(C), 98.4 (C), 109.7 (C), 126.3 (2CH), 126.4 (2CH), 126.9 (CH), 128.2
(2CH), 128.7 (C), 130.4 (2CH), 131.1 (2CH), 135.9 (C), 137.0 (2CH),
137.8 (C), 141.3 (C), 149.9 (C), 161.5 (C). HMRS (EI): m/z calcd for
C25H23IN2O4S M þ Hþ: 575.0496. Found: 575.0489.
RPMI 1640, 100
plates were subsequently centrifuged at 900 G for 10 min and the
supernatant removed. The pellet was dissolved in 100 L of DMSO
m
L/well), plates were incubated for 6 h at 27 ꢀC. The
4.1.4.13. 4-[5-Benzyl-5-methyl-2-(4-nitrophenyl)-4,5-dihydrofuran-
m
3-ylsulfonyl]-N0-hydroxybenzimida-mide (39). White solid, mp
and the absorbance measured in a plate reader at 570 nm. Inhibi-
tory concentration 50% (IC50 Ld) was defined as the concentration of
drug required to inhibit by 50% the metabolic activity of Leishmania
promastigotes compared to the control. IC50 was calculated by non-
linear regression analysis processed on doseeresponse curves,
using TableCurve 2D V5 software. IC50 values represent the mean
value calculated from three independent experiments.
94 ꢀC (ethyl alcohol/water, (1/1)) 1H NMR (DMSO-d6),
d: 1.42 (s, 3H,
CH3), 2.75e3.00 (m, 4H, CH2), 5.97 (bs, 2H), 7.04e7.14 (m, 5H, CH),
7.47 (d, J ¼ 8.4 Hz, 2H, 2CH), 7.68 (d, 2H, J ¼ 8.6 Hz, 2CH), 7.79 (d,
J ¼ 8.4 Hz, 2H, 2CH), 8.25 (d, J ¼ 8.6 Hz 2H, 2CH), 10.00 (s, 1H). 13C
NMR (DMSO-d6), d: 27.2 (CH3), 41.5 (CH2), 45.8 (CH2), 89.9 (C), 112.0
(C), 123.5 (2CH), 126.7 (2CH), 126.8 (2CH), 127.2 (CH), 128.5 (2CH),
130.7 (2CH), 131.0 (2CH), 135.2 (C), 136.1 (C), 138.3 (C), 141.0 (C),
149.0 (C), 150.2 (C), 160.2 (C). HMRS (EI): m/z calcd for C25H23N3O6S
M þ Hþ: 494.1380. Found: 494.80.
Acknowledgments
This work is supported by the CNRS and the Universities of Aix-
Marseille. The authors thank V. Remusat for the NMR spectra
recording and V. Monnier for the mass spectra recording. L. Paloque
is supported by Région PACA/Yelen BDE Ph.D. fellowship.
4.2. Biology
4.2.1. General
Reagents for cell culture media and compound screening
included Schneider’s medium (Invitrogen), RPMI 1640 (PAA), fetal
Appendix. Supplementary material
calf serum (FCS) (PAA), L-glutamine-penicillin-streptomycin solu-
tion (Sigma), thiazolyl blue tetrazolium bromide (MTT) and
dimethyl sulfoxide (DMSO) (Sigma). Stock solutions of amidoxime
derivatives and reference drugs (doxorubicin, amphotericin B and
pentamidine, all from Sigma) were prepared in DMSO.
Supplementary data related to this article can be found online at
doi:10.1016/j.ejmech.2011.04.026.
References
4.2.2. Cytotoxic assays on mouse monocyte macrophages J774A.1
Cytotoxicity was assessed on mouse monocyte macrophages
J774A.1 (ECACC, Salisbury, UK) by a colorimetric assay based on the
mitochondrial reduction of MTT as described previously [19].
J774A.1 cells routinely cultured in RPMI 1640 (without phenol red)
[1] F. Chappuis, S. Sundar, A. Hailu, H. Ghalib, S. Rijal, R.W. Peeling, J. Alvar,
M. Boelaert, Nat. Rev. Microbiol. 5 (2007) 7.
[2] M. Sands, M.A. Kron, R.B. Brown, Rev. Infect. Dis. 7 (1985) 625.
[3] P.G. Bray, M.P. Barrett, S.A. Ward, H.P. De Koning, Trends Parasitol. 19 (2003)
232.
[4] J.D. Berman, Clin. Infect. Dis. 24 (1997) 684.
[5] C. Burri, Parasitology 137 (2010) 1987.
[6] a) F.R. Salamone, B.A. Cunha, Clin. Pharm. 7 (1988) 501;
b) M. Castro, Semin. Respir. Infect. 13 (1998) 296.
[7] L.F. Oliveira, A.O. Schubach, M.M. Martins, S.L. Passos, R.V. Oliveira,
M.C. Marzochi, C.A. Andrade, Acta Trop. 118 (2011) 87.
[8] J. Kotthaus, H. Hungeling, C. Reeh, J. Kotthaus, D. Schade, WeinS, S. Wolffram,
B. Clement, Bioorg. Med. Chem. 19 (2011) 1907.
[9] A.H. Fairlamb, Trends Parasitol. 19 (2003) 488.
[10] T. Zo1ek, D. Maciejewska, Eur. J. Med. Chem. 45 (2010) 1991.
[11] T. Moreno, J. Pous, J.A. Subirana, J.L. Campos, Acta Crystallorg. 66 (2010) 251.
[12] a) J.K. Thuita, S.M. Karanja, T. Wenzler, R.E. Mdachi, J.M. Ngotho, J.M. Kagira,
R. Tidwell, R. Brun, Acta Trop. 108 (2008) 6;
b) D. Chen, R. Marsh, J.A. Aberg, Expert Rev. Anti Infect. Ther. 5 (2007) 921;
c) M.F. Paine, M.Z. Wang, C.N. Generaux, D.W. Boykin, W.D. Wilson, H.P. De
Koning, C.A. Olson, G. Pohlig, C. Burri, R. Brun, G.A. Murilla, J.K. Thuita,
M.P. Barrett, R.R. Tidwell, Curr. Opin. Investig. Drugs 11 (2010) 876.
[13] a) P. Vanelle, M.P. De Meo, J. Maldonado, R. Nouguier, M.P. Crozet, M. Laget,
G. Dumenil, Eur. J. Med. Chem. 25 (1990) 241;
supplemented with 10% FCS, 2 mM
L-glutamine and antibiotics
(100 U/mL penicillin and 100 g/mL streptomycin) were seeded in
m
sterile 96-well plate at an average density of 5 ꢁ 104 cell/mL with
a range of compound concentrations in duplicate (final DMSO
concentration less than 0.5% v/v). Appropriate controls treated with
or without solvent (DMSO), and various concentrations of doxo-
rubicin (positive control), pentamidine and amphotericin B were
added to each set of experiments. After 72 h incubation at 37 ꢀC and
6% CO2, well supernatant was removed. The formation of formazan
was measured by adding MTT (0.5 mg/mL in RPMI 1640, 100
well) and incubating plates for 2 h at 37 ꢀC. The supernatant was
subsequently removed. The pellet was dissolved in 100 L of DMSO
and the absorbance measured in a plate reader at 570 nm. Inhibi-
tory concentration 50% (IC50 J774A.1) was defined as the concen-
tration of drug required to inhibit by 50% the metabolic activity of
J774A.1 cells compared to the control. IC50 was calculated by non-
linear regression analysis processed on doseeresponse curves,
using TableCurve 2D V5 software. IC50 values represent the mean
value calculated from three independent experiments.
mL/
m
b) F. Delmas, M. Gasquet, P. Timon-David, N. Madadi, P. Vanelle, A. Vaille,
J. Maldonado, Eur. J. Med. Chem. 28 (1993) 23;
c) P. Rathelot, N. Azas, H. El Kashef, F. Delmas, C. Di Giorgio, P. Timon-David,
J. Maldonado, P. Vanelle, Eur. J. Med. Chem. 37 (2002) 671;
d) J.A. Upcroft, L.A. Dunn, J.M. Wright, K. Benakli, P. Upcroft, P. Vanelle,
Antimicrob. Agents Chemother. 50 (2006) 344;
e) P. Verhaeghe, N. Azas, S. Hutter, C. Castera-Ducros, M. Laget, A. Dumetre,
M. Gasquet, J.P. Reboul, S. Rault, P. Rathelot, P. Vanelle, Bioorg. Med. Chem. 17
(2009) 4313.
4.2.3. Antileishmanial activity
The effects of the tested compounds on the growth of L. dono-
vani (strain MHOM/IN/00/DEVI, CNR Leishmania, Montpellier,
[14] A. Bouhlel, C. Curti, A. Dumètre, M. Laget, M.D. Crozet, N. Azas, P. Vanelle,
Bioorg. Med. Chem. 18 (2010) 7310.

L. Paloque et al. / European Journal of Medicinal Chemistry 46 (2011) 2984e2991
2991
[15] a) C. Curti, M. Laget, A. Ortiz Carle, A. Gellis, P. Vanelle, Eur. J. Med. Chem. 42
(2007) 880;
[17] S. Chackal-Catoen, Y. Miao, D. Wilson, T. Wenzler, R. Brun, D.W. Boykin, Bio-
org. Med. Chem. 14 (2006) 7434.
b) A. Cohen, M.D. Crozet, P. Rathelot, P. Vanelle, Green Chem. 11 (2009) 1736.
[16] C. Curti, M.D. Crozet, P. Vanelle, Tetrahedron 65 (2009) 200.
[18] K. Seifert, P. Escobar, S.L. Croft, J. Antimicrob. Chemother. 65 (2010) 508.
[19] T.J. Mosmann, J. Immunol. Methods 65 (1983) 55.