Preparation, characterisation and biological evaluation of new N-phenyl amidobenzenesulfonates and N-phenyl ureidobenzenesulfonates inducing DNA double-strand breaks. Part 3. Modulation of ring A

Article abstract of DOI:10.1016/j.ejmech.2018.06.030

N-Phenyl ureidobenzenesulfonates (PUB-SOs) are a new class of anticancer agents blocking the cell cycle progression in S-phase, inducing replicative stress and DNA double-strand breaks (DSBs). In this study, we evaluate the effect of modifying the nature

Full text of DOI:10.1016/j.ejmech.2018.06.030

European Journal of Medicinal Chemistry 155 (2018) 681e694
Contents lists available at ScienceDirect
European Journal of Medicinal Chemistry
journal homepage: http://www.elsevier.com/locate/ejmech
Research paper
Preparation, characterisation and biological evaluation of new N-
phenyl amidobenzenesulfonates and N-phenyl
ureidobenzenesulfonates inducing DNA double-strand breaks. Part 3.
Modulation of ring A
Mathieu Gagn eꢀ -Boulet b, Chahrazed Bouzriba a b, Marvin Godard a b,
a
,
,
,
a, b, *
S eꢀ bastien Fortin
a
CHU de Qu ꢀe bec-Universit ꢀe Laval Research Center, Oncology Division, H o^ pital Saint-François d'Assise, 10 Rue de l'Espinay, Quebec City, QC, G1L 3L5,
Canada
b
Faculty of Pharmacy, Laval University, Quebec City, QC, G1V 0A6, Canada
a r t i c l e i n f o
a b s t r a c t
Article history:
Received 11 January 2018
Received in revised form
N-Phenyl ureidobenzenesulfonates (PUB-SOs) are a new class of anticancer agents blocking the cell cycle
progression in S-phase, inducing replicative stress and DNA double-strand breaks (DSBs). In this study,
we evaluate the effect of modifying the nature and the position of different substituents on ring A of PUB-
SOs on the antiproliferative activity, pharmacological activity as well as on calculated physicochemical,
pharmacokinetics and drug-likeness properties. Modification of the urea group by an amide group led to
new PUB-SO analogs designated as N-phenyl amidobenzenesulfonates (PAB-SOs). The 2-chloroethyl
moiety on ring A was also substituted by different alkyl, cycloalkyl and chloroalkyl groups. The new
PAB-SOs and PUB-SOs blocking the cell cycle progression in S-phase exhibit antiproliferative activity in
14 May 2018
Accepted 12 June 2018
Keywords:
Anticancer agents
N-phenyl amidobenzenesulfonates
N-phenyl ureidobenzenesulfonates
DNA damage
the submicromolar to low micromolar range (0.14e27 mM) on four human cancer cell lines, namely HT-
1080, HT-29, M21 and MCF7. Moreover, selected PUB-SO and PAB-SO derivatives induced the phos-
phorylation of H2AX in M21 cells and do not exhibit or only slightly alkylating activity as confirmed by
the 4-(4-nitrobenzyl)pyridine (NBP) assay. Finally, our results show that structure modifications weakly
affect the calculated physicochemical, pharmacokinetics and drug-likeness properties of PAB-SOs and
PUB-SOs. Therefore, PAB-SOs and PUB-SOs are promising anticancer agents inducing replicative stress
and DNA damage via a mechanism of action unrelated to DNA alkylation.
replicative stress
DNA double-strand breaks
©
2018 Elsevier Masson SAS. All rights reserved.
1
. Introduction
better efficiency and selectivity is urgently needed. To that end, we
developed a new family of anticancer agents named N-phenyl
ureidobenzenesulfonates (PUB-SOs, Fig. 1A) [2e4]. The molecular
structure of PUB-SOs is constituted of 2 aromatic rings (rings A and
B) and a sulfonate group bridging the two aromatic rings. They
were discovered from the screening of N-phenyl-N'-(2-chloroethyl)
ureas as synthetic intermediates of potent antimicrotubule agents
named phenyl 4-(2-oxoimidazolidin-1-yl)-benzenesulfonates and
benzenesulfonamides (Fig. 1B). In contrast with the expected arrest
in G2/M-phase, targeting of the colchicine-binding site and
disruption of microtubules, PUB-SOs instead block the cell cycle
progression in S-phase and induce the phosphorylation of H2AX
Cancer is a group of diseases which figures among the leading
causes of deaths worldwide. The treatments currently available are
not completely effective and exhibit deleterious effects that are
reducing the quality and the quantity of life of cancer patients [1].
Therefore, the development of new anticancer agents exhibiting
Abbreviations: DSBs, double strand-breaks; PUB-SOs, N-phenyl ure-
idobenzenesulfonates; PAB-SOs, N-phenyl amidobenzenesulfonates; NBP, 4-(4-
nitrobenzyl)pyridine; SAR, structure-activity relationships;
phosphorylated.
gH2AX, H2AX
into
replicative stress [5e10]. Hitherto, we found that PUB-SOs bearing
-alkyls, 2-halogens, 2-nitro or 4-hydroxyl groups substituting ring
gH2AX. The latter indicates production of DNA damage and
*
Corresponding author. Faculty of Pharmacy, Laval University, Quebec City, QC,
G1V 0A6, Canada..
2
E-mail address: sebastien.fortin@pha.ulaval.ca (S. Fortin).
https://doi.org/10.1016/j.ejmech.2018.06.030
0223-5234/© 2018 Elsevier Masson SAS. All rights reserved.

682
M. Gagn ꢀe -Boulet et al. / European Journal of Medicinal Chemistry 155 (2018) 681e694
Fig. 1. Molecular structures of A) N-phenyl ureidobenzenesulfonates (PUB-SOs) bearing either an ethylurea, a 2-chloroethylurea or a 3-chloropropylurea group. Molecular structures
of B) N-phenyl-N'-(2-chloroethyl)urea intermediates of phenyl 4-(2-oxoimidazolidin-1-yl)-benzenesulfonates or benzenesulfonamides leading to the discovery of PUB-SOs and C)
SFOM-0046, SFOM-0107 and SFOM-0106.
B and an ethylurea, a 2-chloroethylurea or a 3-chloropropylurea
groups substituting position 4 of ring A lead to derivatives exhib-
iting antiproliferative activity at the micromolar level, blocking the
using a 2-chloroethylurea moiety at position 4 on ring A showed
that PUB-SOs bearing a 2-isopropyl or a 2-iodo groups on ring B
referred to as 2-isopropylphenyl 4-(3-(2-chloroethyl)ureido)
benzenesulfonate (SFOM-0107) and 2-iodophenyl 4-(3-(2-
chloroethyl)ureido)benzenesulfonate (SFOM-0106, Fig. 1C),
respectively are the most potent antiproliferative PUB-SOs pre-
pared so far and exhibit the highest blocking activity of the cell
cycle progression in S-phase [4]. Consequently, the aim of this
study is to evaluate the effect of modifying the ring A of PUB-SOs
using the aforementioned biofunctional assays. To that end, our
study was based on PUB-SOs bearing either a 2-isopropyl or a 2-
iodo substituent on ring B (SFOM-0106 and SFOM-0107) that
gave rise to our most potent compounds, so far. First, we eval-
uated the importance of the urea moiety by its substitution by an
amide group leading to PUB-SO analogs referred to as N-phenyl
amidobenzenesulfonates (PAB-SOs). We also studied the impor-
tance of the chlorine atom and the effect of lengthening and
cyclizing the carbon chain of 2-chloroethylurea moiety by
substituting the urea and amide groups by different alkyl,
cycloalkyl and chloroalkyl groups. In addition, we assessed the
effect to substitute the ring A of PAB-SOs at position 3 to confirm
our previous SAR on PUB-SOs showing that the substitution at
position 3 lost the arrest of the cell cycle progression in S-phase.
Finally, we studied the alkylating potency of PAB-SO and PUB-SO
derivatives using the 4-(4-nitrobenzyl)pyridine (NBP) assay
[12e14] as well as calculated physicochemical, pharmacokinetics
and drug-likeness properties.
cell cycle progression in S-phase and inducing
2e4].
The study of the mechanism of action and DNA damage
gH2AX formation
[
response of the prototypical PUB-SO named 2-ethylphenyl 4-(3-
ethylureido)benzenesulfonate (SFOM-0046, Fig. 1C) evidenced
that S-phase arrest and the induction of
gH2AX is not cell type
specific [11]. Moreover, SFOM-0046 induced DNA damage response
by the activation of ATR-Chk1 and ATM-Chk2 pathways. It also gave
rise to the phosphorylation of RAD52 and not DNA-PKcs that co-
localised with
are mainly repaired by homologous recombination. Finally, SFOM-
046 and several other PUB-SOs showed potent antitumoral ac-
gH2AX foci confirming that the DNA DSBs induced
0
tivity on human HT-1080 fibrosarcoma tumors grafted onto the
chorioallantoic membrane of chick embryos with low toxicity to-
ward the embryos showing that PUB-SOs are a promising family of
anticancer agents [2,11].
So far, structure-activity relationships (SAR) were mainly
based on the modifications of ring B of PUB-SOs because ethyl-
urea and 2-chloroethylurea substituted at position 4 on ring A
were considered requisite for significant antiproliferative and
pharmacologic activities of PUB-SOs. Of note, the modification of
ring A substituted at position 3 or by a 3-chloropropylurea group
led to PUB-SOs exhibiting weaker antiproliferative activities or
losing the arrest of the cell cycle progression in S-phase [2]. In
addition, our previous SAR studies involving ring B modifications

M. Gagn ꢀe -Boulet et al. / European Journal of Medicinal Chemistry 155 (2018) 681e694
683
2
. Chemistry
The preparation of PAB-SOs 1e26 and PUB-SOs 27e38 is illus-
3. Results/discussion
3.1. PAB-SO and PUB-SO derivatives exhibit antiproliferative
activity on human cancer cells
trated in Scheme 1 and was achieved within 3 steps. First, phenyl
nitrobenzenesulfonates 39e41 were prepared by nucleophilic
addition of relevant phenols either to 3- or 4-nitrobenzenesulfonyl
chloride. Resulting phenyl nitrobenzenesulfonates 39e41 were then
reduced to the corresponding phenyl aminobenzenesulfonates
PAB-SOs 1e26 and PUB-SOs 27e38 were assessed for their
antiproliferative activity on four human cancer cell lines namely
HT-1080 fibrosarcoma, HT-29 colon adenocarcinoma, M21 skin
melanoma and MCF7 estrogen-dependent breast adenocarcinoma.
The antiproliferative activity experiments were performed
accordingly to the NCI/NIH Developmental Therapeutics Program
with slight modifications [15]. Topotecan, SFOM-0106, SFOM-0107
and SFOM-0046 were used as reference controls [2,4]. Anti-
proliferative activities are shown in Table 1 and represent the
concentration of the drug inhibiting cell growth by 50% (IC50). In
general, HT-1080 is the most sensitive cancer cell line followed by
HT-29, M21 and MCF7 cell lines, respectively. Moreover, PAB-SOs
4
2e44 with iron powder and HCl in a mixture of EtOH and H
10:1). Finally, PAB-SOs 1e26 were prepared by nucleophilic addi-
tion of phenyl aminobenzenesulfonates 42e44 to the relevant acyl
chloride in a mixture of K CO or triethylamine in acetonitrile while
2
O
(
2
3
PUB-SOs 27e38 were prepared by nucleophilic addition of phenyl
aminobenzenesulfonates 43 and 44 to the corresponding isocyanate
in acetonitrile in the presence or absence of K CO . In some cases,
2 3
the last nucleophilic addition requires heating under pressure in the
presence or absence of microwaves.
Scheme 1. Reagents: (i) relevant phenol, TEA/DCM or TEA/AcOEt; (ii) Fe, HCl, EtOH/H
acyl chloride, MeCN; (iv) relevant isocyanate, K CO /MeCN.
2 2 3
O; (iii) relevant acyl chloride, K CO /MeCN or relevant acyl chloride, TEA/MeCN or relevant
2
3

684
M. Gagn ꢀe -Boulet et al. / European Journal of Medicinal Chemistry 155 (2018) 681e694
Table 1
Antiproliferative activity (IC50) of PAB-SO (1e26) and PUB-SO (27e38) derivatives on human HT-1080 fibrosarcoma, HT-29 colon adenocarcinoma, M21 skin melanoma and
MCF7 breast adenocarcinoma cell lines.
#
R
1
R
2
IC50 (m
M)a
HT-1080
HT-29
M21
MCF7
1
2
3
4
5
6
7
8
9
e
CH
CH
(CH
(CH
CH(CH
C(CH
CH Cl
(CH
CH
CH
CH
CH
(CH
(CH
(CH
(CH
CH(CH
CH(CH
C(CH
C(CH
CH
CH
(CH
(CH
(CH
(CH
CH
CH
(CH
(CH
(CH
(CH
(CH
(CH
(CH
(CH
3
2
21
12
15
11
16
11
0.78
8.2
12
27
22
13
19
16
19
4.5
11
23
23
7.4
11
4.9
11
6.4
13
14
13
15
31
25
20
11
17
13
3.9
>40
21
27
11
11
6.1
9.0
6.7
11
11
13
21
14
9.4
12
13
14
2.2
12
16
27
e
CH
3
e
2
)
)
2
CH
CH
3
e
2
4
3
e
3
)
2
e
3
)
3
e
2
e
2
)
2
Cl
i-Prop
I
i-Prop
I
i-Prop
I
i-Prop
I
i-Prop
I
i-Prop
I
i-Prop
I
i-Prop
I
i-Prop
I
i-Prop
I
i-Prop
I
i-Prop
I
i-Prop
I
i-Prop
I
I
3
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
3
3
3
0
3
2
2
17
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
CH
CH
3
3
2.1
7.2
0.95
2.0
6.3
9.6
4.9
3.3
11
2.6
1.0
0.60
6.5
4.2
3.8
12
0.25
0.14
0.68
0.70
4.7
6.9
0.84
1.2
2.7
2.8
1.3
11
8.1
6.6
9.7
5.3
10
8.6
8.1
6.5
6.6
2.9
2.5
9.0
8.9
5.2
6.3
10
1.1
2.7
2.9
4.0
5.4
1.8
1.5
7.4
7.6
7.4
2
2
2
2
)
2
)
2
)
4
)
4
CH
CH
CH
CH
3
3
3
3
3
)
)
2
2
3
3
)
)
3
3
6.2
8.3
3.9
3.9
14
3
9.5
5.6
4.1
16
2
Cl
Cl
2
2
2
2
2
)
2
)
2
)
3
)
3
Cl
Cl
Cl
Cl
14
12
6.2
9.1
1.1
5.3
6.3
6.8
4.9
6.6
1.5
1.5
6.9
9.6
14
5.1
7.2
4.7
5.6
5.1
5.4
4.6
5.9
1.5
1.9
9.3
4.6
11
2
CH
CH
3
3
2
2
2
2
2
2
2
2
2
)
2
)
2
)
4
)
4
)
2
)
2
)
3
)
3
CH
CH
CH
CH
Cl
Cl
Cl
Cl
3
3
3
3
SFOM-0107 [4]
SFOM-0106 [4]
3
3
3
3
4
5
3
3
3
6
7
8
i-Prop
i-Prop
I
3.9
6.0
6.1
7.4
6.8
7.6
6.1
6.6
7.6
6.2
7.1
6.6
SFOM-0046 [4]
Tpt
Ethyl
e
CH
e
3
CH
2
0.45
0.50
13
0.41
1.6
1.4
6.4
0.20
b
a
IC50 represents the concentration of drug inhibiting cell growth by 50%.
Tpt: topotecan.
b
(
9e26) and PUB-SOs (27e38) substituted at position 4 on ring A are
active in the submicromolar to the low micromolar range on all
cancer cell lines assessed, so far (0.60e27 M and 0.14e14 M,
urea group of PUB-SOs is beneficial but nonessential for the anti-
cancer activity. In contrast and at the exception of compound 7
bearing a chloroacetamide group, PAB-SOs 1e8 substituted at po-
sition 3 on ring A show a weaker activity than derivatives
substituted at position 4 exhibiting an antiproliferative activity in
m
m
respectively). In addition, PUB-SO derivatives are usually more
potent than their PAB-SO counterparts. This result shows that the

M. Gagn ꢀe -Boulet et al. / European Journal of Medicinal Chemistry 155 (2018) 681e694
the micromolar range (8.2 to >40 mM). The carbon chain length
Table 2
685
Effect of selected PAB-SO and PUB-SO derivatives on the cell cycle progression of
M21 cells after 24 h of treatment.
substituting the urea and the amide groups on ring A also impacts
the antiproliferative activity of PAB-SOs and PUB-SOs. Indeed, a
chain length of 5 atoms is optimal for the antiproliferative activity
#
Conc. (
m
M)
Cell cycle progression (%)
(
ethylurea and propylamide moieties); longer or shorter alkyl,
Sub-G1
G0/G1
S
G2/M
cycloalkyl or substituted alkyl groups lead to weaker anti-
proliferative activities. In addition, and except for PAB-SOs 7, 21 and
3
4
5
6
7
1
1
13
14
1
1
1
1
19
20
2
2
2
24
25
39.8
21.9
34.5
24.9
7.8
21.6
22.6
12.2
17.9
13.3
21.5
21.8
26.3
12.3
16.6
7.8
3.0
1.5
0.1
0.7
0.0
0.6
0.2
0.7
0.1
3.7
0.2
0.2
0.2
0.4
0.0
0.1
0.3
0.1
0.2
0.2
0.2
0.8
0.3
0.3
0.1
0.3
0.1
0.8
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.1
64.2
69.0
54.5
61.1
64.1
39.6
60.4
40.0
37.0
41.4
42.6
62.0
62.0
36.7
55.0
60.9
71.1
33.7
27.5
55.3
42.0
58.8
67.6
64.6
62.6
60.6
62.2
43.4
54.4
61.5
60.2
63.9
56.2
56.8
45.2
59.1
14.4
16.0
12.9
20.0
17.1
44.4
28.0
43.8
22.8
28.3
12.9
27.3
23.6
46.9
29.1
18.0
16.5
35.6
34.9
19.3
17.1
31.5
23.4
25.1
26.6
12.2
14.7
38.6
32.0
26.9
12.5
14.3
18.9
30.9
31.9
19.7
18.4
13.5
32.5
18.2
18.8
15.4
11.4
15.5
40.1
26.6
44.3
10.5
14.2
16.0
15.9
21.0
12.1
30.6
37.4
25.2
40.7
8.9
2
2 bearing a strong electrophilic chloroacetamide group, the
presence of a C-terminal chlorine atom on the alkyl chain of the
amide and urea groups on ring A of PAB-SO and PUB-SO derivatives
have a weaker antiproliferative activity than their PAB-SO and PUB-
SO counterparts. These results strongly suggest that the binding
site is sterically hindered and does not require nucleophilic or
strong dipole-dipole interactions for binding. Therefore, PAB-SOs
1
2
5
6
7
8
13 and 14 bearing a propyl group and PUB-SOs 27 and 28 bearing
an ethyl group on ring A exhibit the most potent and promising
antiproliferative activity. PAB-SOs 7, 21 and 22 bearing a chlor-
oacetamide group on ring A are too reactive to be considered for
further biological evaluation. Finally, PAB-SOs 13 and PUB-SO 28 are
the most potent compounds showing antiproliferative activity
1
2
3
7.7
27.7
24.3
10.2
14.5
9.5
11.1
10.1
10.7
9.3
11.8
18.5
9.3
21.2
12.3
13.3
15.2
8.6
ranging from 0.14 to 6.6
mM which is almost equipotent to top-
otecan used as positive control (0.2e1.4
mM).
2
2
2
2
3
6
7
8
9
0
3.2. PAB-SO and PUB-SO derivatives arrest the cell cycle progression
8.7
in S-phase
10.0
10.7
26.9
23.0
17.2
13.5
11.5
27.2
21.7
24.8
12.2
22.8
21.1
SFOM-0107 and SFOM-0106 substituted by either a 2-isopropyl
or a 2-iodo group on ring B and bearing a 2-chloroethylurea moiety
at position 4 on ring A are known to block the cell cycle progression
in S-phase [4]. Therefore, to evaluate the impact of modifying the
ring A of PUB-SOs, PAB-SOs 3e7 and 11e26 as well as PUB-SOs
31
3
3
3
35
36
2
3
4
3
3
7
8
27e38 were selected and were assessed on the cell cycle progres-
sion of M21 cells. Results are summarized in Table 2 and show that
the percentage of cells found in sub-G1, G0/G1, S and G2/M-phases
after 24 h of treatment at 2-folds their respective IC50 that repre-
sents the optimal concentration arresting the cell cycle progression
in S-phase. SFOM-0046, SFOM-0106 and topotecan were used as
positive controls. Control cells were treated with DMSO (0.5%).
First, PAB-SO derivatives substituted at position 3 on ring A do not
induce arrest of the cell cycle progression in S-phase. Moreover,
PAB-SOs 16, 21, 22, 25, 26 and PUB-SOs 31, 32 and 36e38 bearing
sterically hindered or chloroacetamide groups on ring A also lose
their property to arrest the cell cycle progression in S-phase. In
general, PAB-SO derivatives induce an S-phase arrest more effi-
ciently than their PUB-SO counterparts. In addition, the S-phase
arrest is much more important with PAB-SO and PUB-SO de-
rivatives bearing a 2-isopropyl group on ring B than PAB-SO and
PUB-SO counterparts bearing a 2-iodo group. Finally, PAB-SOs 11,13
and 19 as well as PUB-SOs 27, 33 and 34 exhibit the most potent
arrest in S-phase of each series of compounds showing a population
increase in S-phase by 24.7, 24.3, 27.2, 11.8, 18.9 and 12.3%,
respectively.
SFOM-0106
Topotecan
DMSO
1.8
0.5%
compounds, PAB-SOs 12 and 14 as well as PUB-SO 28 and 30 were
also selected to study the impact of the substitution of ring B by a 2-
iodo group on the induction of
stained in blue with 4 ,6-diamidino-2-phenylindole (DAPI) and
g
H2AX. Fig. 2 shows the nucleus
0
g
H2AX foci in red of cells treated with PAB-SO and PUB-SOs at 5-
times their respective IC50 for 24 h. SFOM-0106 and topotecan
were used as positive controls while DMSO (0.25%) was used as a
negative control. As depicted in Fig. 2, all PAB-SOs and PUB-SOs
studied blocking the cell cycle progression in S-phase induce the
phosphorylation of H2AX into
studied on both aromatic rings therefore does not affect the in-
duction of H2AX. Thus, the induction of DNA damage and DNA
gH2AX. The nature of the groups
g
DSBs also characterized the mechanism of action of new PAB-SOs
and PUB-SOs.
3
g
.3. PUB-SOs and PAB-SOs induce phosphorylation of H2AX into
H2AX
3.4. PAB-SOs and PUB-SOs have weak or no alkylating activity
properties in the NBP assay
Our previous SAR studies have shown that PUB-SOs bearing an
ethylurea, a 2-chloroethylurea or a 3-chloropropylurea group on
ring A are blocking the cell cycle progression in S-phase and induce
Alkyl esters of alkyl or aryl sulfonic acids are considered as
potentially genotoxic and alkylating agents in biological systems
since the sulfonate group can be displaced by a variety of nucleo-
philic groups including DNA bases [16,17]. Moreover, aliphatic
organochlorides are also potential alkylating agents because the
chloride atom is a leaving group. Since the molecular structure of
PAB-SOs and PUB-SOs is constituted of 1) a benzyl ester group of
aryl sulfonic acids and 2) a few derivatives bear an aliphatic orga-
nochloride group, we evaluated the alkylating potency of PAB-SOs
the phosphorylation of H2AX into gH2AX [2,4,11]; a marker of DNA
damage and DNA DSBs [5e10]. Therefore, the phosphorylation of
H2AX was used in this study to confirm that the most potent PAB-
SOs (11, 13, 19, 23 and 24) and PUB-SOs (27, 33 and 34) exhibiting
the highest potency to block cell cycle progression in S-phase also
induce DNA damage and DNA DSBs. In addition to the later

686
M. Gagn ꢀe -Boulet et al. / European Journal of Medicinal Chemistry 155 (2018) 681e694
Fig. 2. Effect of PAB-SOs 11e14, 19, 23 and 24 as well as PUB-SOs 27, 28, 30, 33 and 34 on the phosphorylation of H2AX into gH2AX after 24 h of treatment of M21 cells. SFOM-0106,
topotecan (TPT) and DMSO (0.25%) were used as positive and negative controls, respectively.
and PUB-SOs using the colorimetric NBP assay [12,18,19]. NBP assay
is one of the suitable techniques to assess the alkylating potency of
electrophilic compounds. NBP exhibits similar nucleophilic char-
acteristics to those of DNA bases and the assay is based on the
formation of a chromophore in an alkaline medium when alkylat-
ing agents react with NBP. The alkylating activity of PAB-SOs 9,
0.063 ꢀ 10ꢁ3/s) while PAB-SOs 19 and 23 as well as PUB-SOs 29, 33,
SFOM-0046 and SFOM-0107 are very weak or not alkylating agents
ꢁ
3
exhibiting rates constant of 0.033 to 0.0034 ꢀ 10 /s. The alkylating
activity of PAB-SOs and PUB-SOs does not correlate with the arrest
of the cell cycle progression in S-phase nor with the induction of
gH2AX and the nature of the group on ring A. Therefore, the
1
1e14, 19, 23 and 24 as well as PUB-SOs 27e30, 33, 34, SFOM-0046,
alkylating activity experiments show that the alkylating potency is
not prerequisite for the biological activity of PAB-SOs and PUB-SOs.
This corroborates the study by Glowienke et al. using computer-
aided analysis (multiple computer automated structure evalua-
tion) showing that deactivating fragments such as benzene in the
molecular structure of PAB-SOs and PUB-SOs inactivate the alky-
lating potency of sulfonates [20]. In addition, the weak alkylating
potency of PAB-SOs and PUB-SOs confirms also our previous ob-
servations using 4-tert-butyl-(3-(2-chloroethyl)ureido) benzene
(tBCEU) that aliphatic chlorine group may lead to weak alkylation
activity [21].
SFOM-0106 and SFOM-0107 were assessed using the NBP assay.
Chlorambucil was used as positive control. The alkylating potency
in the NBP assay is expressed as the alkylation rate constant
determined by linear regression of the absorbance curve of each
drug. As depicted in Fig. 3, the alkylation rate constant of PAB-SOs
ꢁ3
and PUB-SOs assessed were between 0.49 and 0.0034 ꢀ 10 /s
ꢁ3
comparatively to 5.3 ꢀ 10 /s for chlorambucil (Fig. 3). The NBP
experiment evidenced that PAB-SOs and PUB-SOs are much weaker
alkylating agents than chlorambucil by 11e1600-folds. PAB-SOs 9,
11e14 and 24 as well as PUB-SOs 27, 28, 30, 34 and SFOM-0106 are
weak alkylating agents (alkylation rate constant of 0.49 to

M. Gagn ꢀe -Boulet et al. / European Journal of Medicinal Chemistry 155 (2018) 681e694
687
Fig. 3. A) Relative alkylation of PAB-SOs 9, 11e14, 19, 23 and 24 as well as PUB-SOs 28e30, 33, 34, SFOM-0046, SFOM-0106 and SFOM-0107 by 4-(nitrobenzyl)pyridine (NBP).
Chlorambucil was used as positive control. B) Rate constant of alkylation determined by linear regression of the absorbance curve and ratio of rate constant of chlorambucil (CBL)
comparatively to that of each compound.
3
.5. Effect of structure modifications on pharmacokinetics, drug-
results are available in the supplementary material section. First,
the physicochemical properties of PAB-SO and PUB-SO de-
rivatives are similar. The molecular weights of PAB-SO and PUB-
SO derivatives vary from 347.4 to 494.7 g/mol. The number of
rotatable bonds and H-bond donors vary from 6 to 10 and 1 to 2,
respectively while H-bond acceptors remain constant. The molar
refractivity and the topological polar surface area (TPSA) vary
likeness and physicochemical properties of PAB-SO and PUB-SO
derivatives
Physicochemical properties are important aspects to consider
in drug design and drug development. They affect both phar-
macokinetics and pharmacological properties leading ultimately
to modification of the biological activity. On the one hand, the
structure modifications that we made on PUB-SOs were expected
to change both their physicochemical properties and their bio-
logical activity. On the other hand, many state-of-the art free
web-based computer-aided drug design tools are readily avail-
able to predict pharmacokinetics, drug-likeness and physico-
chemical properties such as pk-CSM [22], admetSAR [23] and
SwissADME [24]. In this context, we used SwissADME tool to
predict the effect of structure modifications of most promising
compounds assessed using our biofunctional assays (compounds
2
from 92.6 to 107.2 and 80.85 to 92.88 Å , respectively. The lip-
ophilicity is expressed as consensus Log P (CLogP) and varies
from 2.99 to 4.20. The water solubility is expressed as Log S and
ꢁ
3
varies from ꢁ4.66 to ꢁ6.15 (9.85e0.27 ꢀ 10 mg/mL). At the
exception of compound 19 bearing a pivalamide moiety at po-
sition 4 on ring A that falls in the class of poorly soluble mole-
cules, all other selected PAB-SO and PUB-SO derivatives display
CLogP and LogS in the same order of magnitude and fall within
the class of moderately soluble compounds. Moreover, Swis-
sADME predicts that a probable high gastrointestinal absorption
(GIA) of all selected PAB-SO and PUB-SO derivatives. In addition,
they are not expected to be permeant to blood-brain barrier nor
substrates of the p-glycoprotein. Finally, at the exception of 34
and SFOM-0106 showing only one violation for Ghose filter
(molecular weight > 480 g/mol), all other selected PAB-SO and
PUB-SO derivatives do not show violation toward Lipinski, Ghose,
11, 12, 13, 14, 19, 23, 24, 27, 28, 30, 33 and 34) on physicochemical,
pharmacokinetics and drug-likeness properties. SwissADME was
selected because it is freely accessible, fast and produce robust
predictive models using different input methods to calculate
several ADME properties of small molecules. A summary of these
predictions is shown in Table 3 and the complete prediction

688
M. Gagn ꢀe -Boulet et al. / European Journal of Medicinal Chemistry 155 (2018) 681e694
Table 3
Pharmacokinetics, drug-likeness and biophysical properties of selected PAB-SO and PUB-SO derivatives calculated using the free web-based SwissADME application [24].
#
RBa
H-BAb
H-BDc
MRd
TPSAe (Å2)
CLogPf
LogSg
SClassh
GIAi
BBBPj
Pgpk
Drug-like (# viol.)l
1
1
1
1
1
2
2
2
2
3
3
3
1
7
6
8
7
7
8
7
8
7
8
10
9
8
8
9
3
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
7
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
94.4
92.6
99.3
97.4
103.8
99.2
97.4
97.6
95.8
100.6
107.2
105.4
92.8
100.6
102.4
114.8
80.85
80.85
80.85
80.85
80.85
80.85
80.85
92.88
92.88
92.88
92.88
92.88
92.88
92.88
92.88
104.89
3.56
3.29
3.91
3.64
4.20
3.80
3.53
3.27
3.02
3.38
3.84
3.60
2.99
3.26
3.52
1.86
ꢁ5.18
ꢁ4.69
ꢁ5.56
ꢁ5.06
ꢁ6.15
ꢁ5.24
ꢁ4.75
ꢁ5.15
ꢁ4.66
ꢁ5.21
ꢁ5.76
ꢁ5.26
ꢁ4.81
ꢁ4.89
ꢁ5.38
ꢁ3.02
MS
MS
MS
MS
PS
MS
MS
MS
MS
MS
MS
MS
MS
MS
MS
S
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
Yes
Yes (0)
Yes (0)
Yes (0)
Yes (0)
Yes (0)
Yes (0)
Yes (0)
Yes (0)
Yes (0)
Yes (0)
Yes (0)
Yes (1)
Yes (0)
Yes (1)
Yes (0)
Yes (0)
2
3
4
9
3
4
7
8
0
3
4
SFOM-0046
SFOM-0106
SFOM-00107
m
Tpt
a
RB: number of rotatable bonds.
H-BA: number of H-bond acceptors.
H-BD: number of H-bond acceptors.
MR: molar refractivity.
TPSA: topological polar surface area.
CLogP: consensus Log P (average from iLOGP, XLOGP3, WLOGP, MLOGP and Silicos-IT Log P).
LogS: Ali topological method Log S.
b
c
d
e
f
g
h
i
SClass: Ali solubility class (insoluble (IS) < ꢁ10 < poorly soluble (PS) < ꢁ6 < moderately soluble (MS) < ꢁ4 < soluble (S) < ꢁ2 < very soluble (VS) < 0 < highly soluble (HS)).
GIA: gastrointestinal absorption (H means high).
j
BBBP: blood-brain barrier permeability.
Pgp: p-glycoprotein substrates.
Druglike: drug-likeness indices (bioavailability) from Lipinski, Ghose, Veber, Egan and Muegge filters. # viol: number of violations of the 5 filters.
Tpt: topotecan.
k
l
m
Veber, Egan and Muegge filters. These results show that our
selected PAB-SOs and PUB-SOs exhibit high drug-likeness and
bioavailability scores. Altogether, these results show that struc-
ture modifications weakly affect the physicochemical properties
of PAB-SOs and PUB-SOs. Moreover, their pharmacokinetics and
drug-likeness properties calculated using SwissADME are also
similar. These predictions confirm that the results obtained from
our biofunctional assays are mainly due to the docking and the
affinity of PAB-SOs and PUB-SOs to biological target that has not
been identified yet.
5. Experimental protocols
5.1. Biological methods
5.1.1. Cell lines culture
HT-1080 human fibrosarcoma, HT-29 human colon carcinoma,
M21 human skin melanoma and MCF7 human breast carcinoma
were purchased from the American Type Culture Collection
(Manassa, VA). Cells were cultured in DMEM medium containing
sodium bicarbonate, high glucose concentration, glutamine and
sodium pyruvate (Hyclone, Logan, UT) supplemented with 5% of
fetal bovine serum (FBS, Invitrogen, Burlington, ON) and were
ꢂ
maintained at 37 C in a moisture-saturated atmosphere containing
4
. Conclusion
2
5% CO .
In conclusion, we report herein the synthesis and the bio-
logical activity of 26 novel PAB-SO and 12 PUB-SO derivatives.
They were evaluated for their antiproliferative activity on four
human cancer cell lines (HT-1080, HT-29, M21 and MCF7) and for
their potency to arrest the cell cycle progression in S-phase. Our
SAR study shows that PAB-SOs and PUB-SOs must be substituted
at position 4 on the aromatic ring A to maintain a significant
antiproliferative activity in the low micromolar to sub-
micromolar range and to arrest the cell cycle progression in S-
phase. PAB-SOs and PUB-SOs blocking the cell cycle progression
in S-phase induce also DNA DSBs as shown by the induction of
5.1.2. Antiproliferative activity assay
The growth inhibition potency of all compounds was assessed
using the procedure recommended by the National Cancer Institute
(NCI) Developmental Therapeutics Program for its drug screening
program with slight modifications [15]. Briefly, 96-well Costar mi-
crotiter clear plates were seeded with 75 mL of a suspension of
3
3
3
either HT-1080 (2.5 ꢀ 10 ), HT-29 (4.0 ꢀ 10 ), M21 (3.0 ꢀ 10 ) or
3
MCF7 (2.5 ꢀ 10 ) cells per well in DMEM. Freshly solubilized drugs
in DMSO (40 mM) were diluted in fresh DMEM and 75 mL aliquots
containing serially diluted concentrations of the drug were added.
Final drug concentrations ranged from 100 M to 78 nM. DMSO
g
H2AX. Moreover, the NBP assay shows that PUB-SOs and PAB-
m
SOs exhibit no or only weak alkylating potency and confirms
that alkylating activity is not essential to their biological activity.
In addition, our results show that structure modifications weakly
affect the calculated physicochemical, pharmacokinetics and
drug-likeness properties of PAB-SOs and PUB-SOs. Finally, our
work confirms that urea group is not essential for the activity of
this class of compounds and paves the way for further explora-
tion of this moiety for the development and optimization of this
promising family of new anticancer agents.
concentration was kept constant at <0.5% (v/v) to prevent any
related toxicity. Plates were incubated for 48 h, after which growth
was stopped by the addition of cold trichloroacetic acid to the wells
(10% w/v, final concentration). Afterward, plates were incubated aꢁ
ꢂ
4 C for 1 h. Then, plates were washed 5-times with distilled water
and a sulforhodamine B solution (0.1% w/v) in 1% acetic acid was
added to each well. After 15 min at room temperature, the
exceeding dye was removed and was washed 5-times with a so-
lution of 1% acetic acid. Bound dye was solubilized in 20 mM Tris

M. Gagn ꢀe -Boulet et al. / European Journal of Medicinal Chemistry 155 (2018) 681e694
689
base and the absorbance was read using an optimal wavelength
530e580 nm) with a SpectraMax® i3x (Molecular Devices). Data
was determined by linear regression of the absorbance curve
generated for each drug.
(
obtained from treated cells were compared to the control cell plates
fixed on the treatment day and the percentage of cell growth was
thus calculated for each drug. The experiments were done at least
twice in triplicate. The assays were considered valid when the co-
efficient of variation was <10% for a given set of conditions within
the same experiment.
5.2. Chemical methods
5.2.1. General
Proton NMR spectra were recorded on a Bruker AM-300 spec-
trometer (Bruker, Germany) or an NMR Varian Inova 400 MHz.
Chemical shifts (d) are reported in parts per million (ppm). Re-
5
.1.3. Cell cycle progression analysis
M21 cells (2.5 ꢀ 10 ) were seeded onto the six-well plates and
actions requiring microwave heating were performed with an
Initiator system (Biotage, Charlottesville, VA). Uncorrected melting
points were determined on an electrothermal melting point
apparatus. HPLC analyses were performed using a Prominence
LCMS-2020 system with binary solvent equipped with an UV/vis
photodiode array and an APCI probe (Shimadzu, Columbia, MD).
Compounds were eluted within 25 min on an Alltech Alltima C18
reversed-phase column (5 mm, 250 mm ꢀ 4.6 mm) equipped with
an Alltech Alltima C18 precolumn (5 mm, 7.5 mm ꢀ 4.6 mm) with a
5
incubated for 24 h. Then, after incubation of M21 cells with selected
PAB-SOs and PUB-SOs at 2- and 5-times their respective IC50 for
2
saline (PBS) and resuspended in 250 mL of PBS. Cells were fixed by
the addition of 750 mL of ice-cold EtOH under agitation and stored
4 h, the cells were trypsinized, washed with phosphate buffered
ꢂ
at ꢁ4 C until analysis. Prior to fluorescence-activated cell sorting
analysis, cells were washed with PBS and resuspended in 500 mL of
PBS containing 2 mg/mL DAPI. Cell cycle distribution of fixed cell
suspensions was analyzed using an LSR II flow cytometer (BD
Biosciences, Franklin Lakes, NJ).
2
MeOH/H O linear gradient at 1.0 mL/min. Some HPLC analyses
were also performed using an ACQUITY Arc system (Waters, Mis-
sissauga, Ontario). The purity of all final compounds was >95%.
HRMS were recorded by direct injection in a TOF system 6210 series
mass spectrometer (Agilent technologies, Santa Clara, CA). All
chemicals were supplied by Aldrich Chemicals (Milwaukee, WI),
VWR International (Mont-Royal, QC, Canada) or Enamine LLC
(Cincinnati, USA) and used as received unless specified otherwise.
Liquid flash chromatography was performed on silica gel F60, 60 Å,
5
.1.4. Immunofluorescence of H2AX
Cover slides (22 mm ꢀ 22 mm) sterilized with 70% (v/v) EtOH
were placed in six-well plates. To promote cell adhesion, cover
slides were treated with 1.5 mL of a fibronectin solution in PBS
ꢂ
(
5
m
g/mL) for 1 h at 37 C. Slides were then rinsed thrice with PBS.
5
M21 cells (1 ꢀ 10 ) were seeded onto the plates and incubated for
40e63 m
m supplied by Silicycle (Qu eꢀ bec, QC, Canada) using an FPX
2
4 h. Cells were then incubated with selected PAB-SOs and PUB-SOs
flash purification system (Biotage, Charlottesville, VA), and using
solvent mixtures expressed as v/v ratios. Solvents and reagents
were used without purification unless specified otherwise. The
progress of all reactions was monitored by TLC on precoated silica
gel 60 F254 TLC plates (VWR). The chromatograms were viewed
under UV light at 254 and/or 265 nm.
ꢂ
at 2- and 5-times their respective IC50 for 24 h at 37 C. The control
solution consisted of DMSO dissolved in culture medium (0.25%, v/
v). Cells were fixed using 1.5 mL of formaldehyde at 3.7% and per-
meabilized by addition of a saponin and bovine serum albumin
(
BSA) solution (0.1% and 3% w/v in PBS, respectively). Cells were
incubated with mouse anti-H2AX pS139 antibody (Millipore, Bill-
erica, MA) (1:8000). Cover slides were next incubated for 3 h at
room temperature and then washed thrice with PBS supplemented
with 0.05% (v/v) Tween 20 (PBS-T). SaponinꢁBSA solution con-
taining goat anti-mouse IgG conjugated to AlexaFluor 594 (Invi-
trogen, Burlington, Ontario, Canada) (1:1000, 2 mg/mL), and DAPI
5.2.2. General preparation of compounds 1e26
Method A. The relevant acid chloride was added to a solution of
the appropriate aniline (42e44) in acetonitrile (2 mL) with trie-
ꢂ
thylamine (1.2 Eq). The reaction mixture was stirred at 80 C under
pressure for 1e7 days. The mixture was cooled at room tempera-
ture and the solvent was evaporated under reduced pressure. The
residue was diluted with in AcOEt (10 mL) and was washed suc-
cessively with water (10 mL) and brine (10 mL), dried over sodium
sulfate, filtered and evaporate to dryness under reduced pressure.
The residue was purified by flash chromatography on silica gel.
Method B. The relevant acid chloride was added to a solution of
the appropriate aniline (42e44) in acetonitrile (2 mL) and with or
without triethylamine (1.2 Eq) and potassium carbonate (1.2 Eq).
The reaction mixture was stirred at room temperature for 1e5 days.
After completion of the reaction, the solvent was evaporated under
reduced pressure, the mixture was diluted in AcOEt (10 mL) and
was washed successively with water (10 mL) and brine (10 mL),
dried over sodium sulfate, filtered and evaporate to dryness under
reduced pressure. The residue was purified by flash chromatog-
raphy on silica gel.
(
Sigma, Oakville, Ontario, Canada) (1:3000, 1 mg/mL) was then
added. The cover slides were incubated for 2 h at room temperature
and then washed 5-times with PBS-T. The cover slides were
mounted with Fluoromount-G (Southern Biotech no: 0100e01).
Cells were visualized using an epifluorescence microscope
(
Olympus BX51, Center Valley, PA) with a Qimaging RETIGA EXi
camera (Qimaging, Surrey, British Columbia, Canada).
5.1.5. Kinetics of alkylation of 4-(4-nitrobenzyl)pyridine by PUB-
SOs and PAB-SOs
The kinetics of alkylation of PAB-SOs and PUB-SOs was assessed
by a colorimetric assay developed by Bardos et al. [14]. Chlor-
ambucil was used as positive control. Briefly, 1 mL of ethanol con-
taining 400 nmol of the selected drug, 1 mL of a solution of NBP
(
10% (v/v) in ethanol 95%),1 mL of acetate buffer solution (50 mM at
pH 4.3) and 1 mL of ethanol were mixed together and kept on ice
prior to the initiation of the reaction. The reaction was initiated by
heating the solutions at 80 C in a shaking water bath. The reaction
5.2.3. Characterization of compounds 1e26
ꢂ
5.2.3.1. 2-Isopropylphenyl
3-acetamidobenzenesulfonate
(1).
was stopped by cooling down the mixtures on ice for 5 min after
periods of incubation of 0, 30, 60 and 90 min. Then, 1.5 mL of a
solution of 0.1 M KOH:ethanol (1:2 (v/v)) was added to the reaction
mixture. Thereafter, the mixtures were vortexed for 12 s and
Method A, 7 days, flash chromatography (hexanes/methylene
ꢂ
1
chloride (50:50)). Yield: 61%; pale yellow solid; mp: 98e99 C; H
NMR (CDCl ): 8.38 (brs, 1H, NH), 8.10e7.97 (m, 2H, Ar), 7.55e7.43
(m, 2H, Ar), 7.26e7.18 (m, 2H, Ar), 7.09e6.98 (m, 2H, Ar), 3.16e3.06
3
d
13
2
.5 min later the absorbance was read at 570 nm. The values were
(m, 1H, CH), 2.17 (s, 3H, CH
NMR (CDCl ): 169.3, 146.9, 141.7, 139.4, 136.3, 130.0, 127.6, 127.3,
126.7, 125.3, 123.4, 121.8, 118.8, 26.8, 24.4, 23.1; MS (APSIþ) m/z
3
), 1.04 (d, 6H, J ¼ 6.8 Hz, 2x CH
3
);
C
compared with those obtained using a blank where the drug so-
lutions were replaced by ethanol. The rate constant of alkylation
3
d

690
M. Gagn ꢀe -Boulet et al. / European Journal of Medicinal Chemistry 155 (2018) 681e694
þ
found 334.10; C17
H20NO
4
S (M þ H) expected, 334.11.
7.26e7.17 (m, 2H, Ar), 7.09e7.05 (m, 1H, Ar), 7.00e6.99 (m, 1H, Ar),
4
.15 (s, 2H, CH
2
), 3.15e3.08 (m, 1H, CH), 1.04 (d, 6H, J ¼ 6.9 Hz, 2x
13
5
.2.3.2. 2-Isopropylphenyl 3-propionamidobenzenesulfonate (2).
CH
3
); C NMR (CDCl ): 165.0, 146.8, 141.7, 138.2, 136.7, 130.1,
3
d
Method A, 7 days, flash chromatography (hexanes/methylene
127.6, 127.3, 126.8, 125.7, 124.4, 121.9, 119.5, 43.0, 26.8, 23.1; MS
þ
chloride (75:25) to methylene chloride). Yield: 47%; colorless oil;
(APSIþ) m/z found 368.00; C17
H
19ClNO
4
S (M þ H) expected,
1
H NMR (CDCl
3
):
d
8.48 (brs, 1H, NH), 8.27e7.85 (m, 2H, Ar),
368.07.
7.53e7.51 (m, 1H, Ar), 7.45e7.41 (m, 1H, Ar), 7.25e7.17 (m, 2H, Ar),
7
CH
NMR (CDCl
.08e6.97 (m, 2H, Ar), 3.15e3.09 (m, 1H, CH), 2.40 (q, 2H, J ¼ 7.5 Hz,
5.2.3.8. 2-Isopropylphenyl 3-(3-chloropropanamido)benzenesulfo-
nate (8). Method B with potassium carbonate, 3 days, flash chro-
13
2
), 1.19 (t, 3H, J ¼ 7.5 Hz, CH
3
), 1.04 (d, 6H, J ¼ 6.9 Hz, 2x CH
3
);
C
3
): d 173.3, 146.9, 141.7, 139.6, 136.3, 130.0, 127.6, 127.3,
matography (hexanes/ethyl acetate (75:25)). Yield: 84%; colorless
1
1
26.7, 125.3, 123.2, 121.8, 118.8, 30.5, 26.8, 23.1, 9.5; MS (APSIþ) m/z
oil; H NMR (CDCl
3
):
d
8.63 (brs, 1H, NH), 8.16e8.13 (m, 1H, Ar),
þ
found 348.05; C18
H22NO
4
S (M þ H) expected, 348.13.
8.02e7.98 (m, 1H, Ar), 7.56e7.54 (m, 1H, Ar), 7.47e7.43 (m, 1H, Ar),
.26e7.18 (m, 2H, Ar), 7.09e7.06 (m, 1H, Ar), 7.01e6.99 (m, 1H, Ar),
3.82 (t, 2H, J ¼ 6.1 Hz, CH ), 3.15e3.08 (m, 1H, CH), 2.85 (t, 2H,
J ¼ 6.1 Hz, CH ), 1.05 (d, 6H, J ¼ 6.9 Hz, 2x CH
169.0, 146.8, 141.7, 139.0, 136.4, 130.1, 127.7, 127.3, 126.8, 125.6,
7
5.2.3.3. 2-Isopropylphenyl
3-butyramidobenzenesulfonate
(3).
2
13
Method A, 7 days, flash chromatography (hexanes/methylene
2
3 3
); C NMR (CDCl ):
ꢂ
1
chloride (50:50)). Yield: 33%; white solid; mp: 78e79 C; H NMR
CDCl ): 8.49 (brs, 1H, NH), 8.11e8.05 (m, 2H, Ar), 7.53e7.51 (m,
H, Ar), 7.45e7.41 (m, 1H, Ar), 7.26e7.17 (m, 2H, Ar), 7.08e7.05 (m,
H, Ar), 7.00e6.98 (m, 1H, Ar), 3.17e3.07 (m, 1H, CH), 2.35 (t, 2H,
), 1.76e1.67 (m, 2H, CH
), 1.04 (d, 6H, J ¼ 6.8 Hz, 2x
); C NMR (CDCl ): 172.9, 146.9,
41.7, 139.7, 136.3, 129.9, 127.6, 127.3, 126.8, 125.4, 123.2, 121.8, 119.1,
d
(
1
1
3
d
123.7, 121.8, 119.1, 40.0, 39.6, 26.8, 23.1; MS (APSIþ) m/z found
þ
382.00; C18
H
21ClNO
4
S (M þ H) expected, 382.09.
J ¼ 7.3 Hz, CH
2
2
5.2.3.9. 2-Isopropylphenyl
4-acetamidobenzenesulfonate
(9).
13
CH
3
), 0.94 (t, 3H, J ¼ 7.3 Hz, CH
3
3
d
Method A, 7 days, flash chromatography (methylene chloride/
1
1
methanol (97:3)). Yield: 59%; yellow oil;
8.85e8.69 (brs, 1H, NH), 7.97e7.53 (m, 4H, Ar), 7.25e7.17 (m, 2H,
Ar), 7.07 (t, 1H, J ¼ 7.7 Hz, Ar), 7.00e6.98 (m, 1H, Ar), 3.14e3.04 (m,
3
H NMR (CDCl ):
3
C
9.2, 26.7, 23.1, 19.0, 13.6; MS (APSIþ) m/z found 362.10;
d
þ
19
H
24NO
4
S (M þ H) expected, 362.14.
1
3
1
H, CH), 2.18 (s, 3H, CH
3
), 1.03 (d, 6H, J ¼ 6.9 Hz, 2x CH
3
); C NMR
5.2.3.4. 2-Isopropylphenyl
3-hexanamidobenzenesulfonate
(4).
(CDCl ): 169.7, 146.8, 143.9, 141.7, 129.8, 129.6, 127.6, 127.3, 126.7,
3
d
Method A, 7 days, flash chromatography (hexanes/ethyl acetate
121.8, 119.3, 26.7, 24.6, 23.1, MS (APSIþ) m/z found 334.05;
1
þ
(
90:10)). Yield: 60%; colorless oil; H NMR (CDCl
NH), 8.13e8.11 (m, 1H, Ar), 8.04 (s, 1H, Ar), 7.52e7.50 (m, 1H, Ar),
.45e7.41 (m, 1H, Ar), 7.26e7.17 (m, 2H, Ar), 7.08e7.05 (m, 1H, Ar),
3
):
d
8.46 (brs, 1H,
C
17
H20NO
4
S (M þ H) expected, 334.11.
7
5.2.3.10. 2-Iodophenyl
4-acetamidobenzenesulfonate
(10).
7
CH
.01e6.99 (m, 1H, Ar), 3.17e3.07 (m, 1H, CH), 2.37 (t, 2H, J ¼ 7.4 Hz,
Method B with triethylamine, 5 days, flash chromatography
2
), 1.71e1.67 (m, 2H, CH
2
), 1.30e1.29 (m, 4H, 2x CH
2
), 1.04 (d, 6H,
(methylene chloride to methylene chloride/ethyl acetate (90:10)).
1
3
ꢂ
1
J ¼ 6.9 Hz, 2x CH
3
), 0.86 (t, 3H, J ¼ 4.9 Hz, CH
3
); C NMR (CDCl ):
3
Yield: 58%; white solid; mp: 113e115 C; H NMR (CDCl
3
): d 8.20 (s,
d
172.6, 146.8, 141.7, 139.6, 136.2, 129.9, 127.5, 127.3, 126.7, 125.3,
1H, NH), 7.82e7.80 (m, 2H Ar), 7.74e7.72 (m, 3H, Ar), 7.33e7.26 (m,
13
1
23.2, 121.8, 118.8, 37.5, 31.3, 26.7, 25.2, 23.1, 22.4, 13.9; MS (APSIþ)
2H, Ar), 6.98e6.94 (m, 1H, Ar), 2.21 (s, 3H, CH
3
); C NMR (CDCl
3
):
þ
m/z found 390.15; C21
H28NO
4
S (M þ H) expected, 390.17.
d
169.3, 149.8, 144.0, 140.2, 130.2, 129.6, 129.5, 128.6, 122.9, 119.1,
þ
9
0.3, 24.8; MS (APSIþ) m/z found 417.90; C14
4
H13INO S (M þ H)
5.2.3.5. 2-Isopropylphenyl 3-isobutyramidobenzenesulfonate (5).
expected, 417.96.
Method B without base, 1 day, flash chromatography (hexanes/
ꢂ
1
ethyl acetate (90:10)). Yield: 56%; orange solid; mp: 95e96 C; H
NMR (CDCl ): 8.20e8.18 (m,1H, Ar), 7.98e7.95 (m, 2H, Ar and NH),
.54e7.51 (m, 1H, Ar), 7.47e7.43 (m, 1H, Ar), 7.27e7.19 (m, 2H, Ar),
.10e7.06 (m, 1H, Ar), 7.00e6.98 (m, 1H, Ar), 3.17e3.10 (m, 1H, CH),
5.2.3.11. 2-Isopropylphenyl 4-propionamidobenzenesulfonate (11).
3
d
Method A, 7 days, flash chromatography (hexanes/methylene
1
7
7
chloride (50:50)). Yield: 24%; colorless oil; H NMR (CDCl
3
):
d
7.89e7.71 (m, 5H, Ar and NH), 7-26-7.19 (m, 2H, Ar), 7.09 (t, 1H,
J ¼ 7.9 Hz, Ar), 7.00e6.98 (m, 1H, Ar), 3.17e3.07 (m, 1H, CH), 2.43 (q,
2H, J ¼ 7.4 Hz, CH ), 1.23 (t, 3H, J ¼ 7.4 Hz, CH ), 1.05 (d, 6H,
172.7, 146.9, 143.6, 141.7,
2
.58e2.52 (m, 1H, CH), 1.23 (d, 6H, J ¼ 6.8 Hz, 2x CH
3
), 1.05 (d, 6H,
176.0, 146.9, 141.7, 139.5,
13
J ¼ 6.9 Hz, 2x CH
3
); C NMR (CDCl
3
):
d
2
3
13
136.3, 130.0, 127.5, 127.3, 126.7, 125.3, 123.3, 121.9, 118.8, 36.6, 26.7,
J ¼ 6.8 Hz, 2x CH
3 3
); C NMR (CDCl ): d
þ
2
3.1, 19.5; MS (APSIþ) m/z found 362.05; C19
H24NO
4
S (M þ H)
130.0, 129.7, 127.4, 127.2, 126.7, 121.9, 119.1, 30.8, 26.7, 23.1, 9.3; MS
expected, 362.14.
(APSIþ) m/z found 348.05; HRMS (ESI) m/z found 348.1262;
þ
C
18
H22NO
4
S (M þ H) expected, 348.1270.
5.2.3.6. 2-Isopropylphenyl
3-pivalamidobenzenesulfonate
(6).
Method A, 7 days, flash chromatography (hexanes/ethyl acetate
5.2.3.12. 2-Iodophenyl
Method A, 5 days, flash chromatography (methylene chloride/ethyl
4-propionamidobenzenesulfonate
(12).
1
(
80:20)). Yield: 25%; yellow oil; H NMR (CDCl
3
): d 8.16e8.14 (m,
1
1
H, Ar), 8.02e8.01 (m, 1H, Ar), 7.95 (brs, 1H, NH), 7.51e7.49 (m, 1H,
acetate (90:10)). Yield: 70%; yellowish oil; H NMR (CDCl
(s, 1H, NH), 7.81e7.70 (m, 5H, Ar), 7.21e7.25 (m, 2H, Ar), 6.97e6.93
(m, 1H, Ar), 2.43 (q, 2H, J ¼ 7.5 Hz, CH ), 1.19 (t, 3H, J ¼ 7.5 Hz, CH );
173.2, 149.8, 144.2, 140.2, 130.2, 129.7, 129.2,
3
): d 8.28
Ar), 7.44e7.40 (m, 1H, Ar), 7.26e7.24 (m, 1H, Ar), 7.21e7.17 (m, 1H,
Ar), 7.07e7.04 (m, 1H, Ar), 6.96e6.94 (m, 1H, Ar), 3.20e3.09 (m, 1H,
2
3
1
3
13
CH), 1.30 (s, 9H, 3x CH
3
), 1.05 (d, 6H, J ¼ 6.9 Hz 2x CH
3
); C NMR
3
C NMR (CDCl ): d
(
CDCl ): 177.4, 146.9, 141.7, 139.6, 136.3, 129.8, 127.5, 127.2, 126.7,
3
d
128.7, 122.9, 119.2, 90.3, 30.8, 9.4; MS (APSIþ) m/z found 431.95;
þ
1
25.8, 123.4, 121.9, 119.3, 39.8, 27.4, 26.7, 23.1; MS (APSIþ) m/z
HRMS (ESI) m/z found 431.9763; C15
H15INO
4
S (M þ H) expected,
þ
found 376.10; C20
H26NO
4
S (M þ H) expected, 376.16.
431.9767.
5
(
.2.3.7. 2-Isopropylphenyl 3-(2-chloroacetamido)benzenesulfonate
7). Method B with potassium carbonate, 4 days, flash chroma-
tography (hexanes/methylene chloride (80:20)). Yield: 73%; color-
less oil; 1H NMR (CDCl
): 8.79 (brs, 1H, NH), 8.15 (m, 1H, Ar),
.98e7.96 (m, 1H, Ar), 7.61e7.59 (m, 1H, Ar), 7.49e7.45 (m, 1H, Ar),
5.2.3.13. 2-Isopropylphenyl 4-butyramidobenzenesulfonate (13).
Method A, 7 days, flash chromatography (hexanes/methylene
1
chloride (75:25)). Yield: 37%; colorless oil; H NMR (CDCl
3
):
d
8.37
3
d
(brs,1H, NH), 7.98e7.53 (m, 4H, Ar), 7.26e7.18 (m, 2H, Ar), 7.10e7.06
(m, 1H, Ar), 7.00e6.98 (m, 1H, Ar), 3.12e3.09 (m, 1H, CH), 2.37 (t,
7

M. Gagn ꢀe -Boulet et al. / European Journal of Medicinal Chemistry 155 (2018) 681e694
691
2
H, J ¼ 7.4 Hz, CH
2
), 1.76e1.67 (m, 2H, CH
2
), 1.04 (d, 6H, J ¼ 6.9 Hz,
147.0, 143.5, 141.8, 130.3, 129.7, 127.4, 127.2, 126.7, 121.8, 119.4, 40.0,
13
2
x CH
3
), 0.95 (t, 3H, J ¼ 7.4 Hz, CH
3
); C NMR (CDCl ): 172.1, 146.9,
3
d
27.5, 26.7, 23.1; MS (APSIþ) m/z found 376.05; HRMS (ESI) m/z
þ
143.6, 141.7, 130.0, 129.7, 127.5, 127.2, 126.7, 121.9, 119.1, 39.6, 26.7,
found 376.1576; C20
H26NO
4
S (M þ H) expected, 376.1583.
2
3
3.1,18.8, 13.7; MS (APSIþ) m/z found 362.10; HRMS (ESI) m/z found
þ
62.1418; C19
H24NO
4
S (M þ H) expected, 362.1427.
5.2.3.20. 2-Iodophenyl
4-pivalamidobenzenesulfonate
(20).
Method B without base, 2 days, flash chromatography (methylene
5
.2.3.14. 2-Iodophenyl
4-butyramidobenzenesulfonate
(14).
chloride to methylene chloride/ethyl acetate (95:5)). Yield: 74%;
ꢂ
1
Method B with triethylamine, 5 days, flash chromatography
yellowish solid; mp: 174e175 C; H NMR (CDCl
3
): d 7.84e7.82 (m,
(
5
methylene chloride/hexanes (90:10) to methylene chloride). Yield:
2H, Ar), 7.75e7.72 (m, 3H, Ar), 7.64 (s, 1H, NH), 7.34e7.29 (m, 2H,
ꢂ
1
13
8%; white solid; mp: 105e106 C; H NMR (CDCl
3
):
d
8.03 (s, 1H,
Ar), 6.99e6.95 (m, 1H, Ar), 1.32 (s, 9H, 3x CH
3 3
); C NMR (CDCl ):
NH), 7.82e7.80 (m, 2H, Ar), 7.76e7.72 (m, 3H, Ar), 7.33e7.26 (m, 2H,
Ar), 6.98e6.94 (m,1H, Ar), 2.38 (t, 2H, J ¼ 7.4 Hz, CH ),1.78e1.69 (m,
); C NMR (CDCl ): 172.2,
49.8, 144.0, 140.2, 130.2, 129.6, 129.4, 128.6, 122.9, 119.1, 90.3, 39.6,
d 177.1, 149.9, 143.8, 140.1, 130.2, 129.9, 129.6, 128.5, 123.0, 119.3,
2
90.3, 40.0, 27.5; MS (APSIþ) m/z found 459.95; C17
4
H19INO S
13
þ
2
1
H, CH
2
), 0.97 (t, 3H, J ¼ 7.4 Hz, CH
3
3
d
(M þ H) expected, 460.01.
1
4
8.8, 13.7; MS (APSIþ) m/z found 445.95; HRMS (ESI) m/z found
5.2.3.21. 2-Isopropylphenyl 4-(2-chloroacetamido)benzenesulfonate
(21). Method B with potassium carbonate, 1 day, flash chroma-
tography (methylene chloride/methanol (95:5)). Yield: 96%; white
þ
45.9916; C16
H17INO
4
S (M þ H) expected, 445.9924.
ꢂ
1
5.2.3.15. 2-Isopropylphenyl 4-hexanamidobenzenesulfonate (15).
solid; mp: 151e153 C; H NMR (CDCl
7.88e7.85 (m, 2H, Ar), 7.77e7.75 (m, 2H, Ar), 7.28e7.21 (m, 2H, Ar),
7.13e7.09 (m, 1H, Ar), 7.02e7.00 (m, 1H, Ar), 4.23 (s, 2H, CH ),
); C NMR
164.2, 146.9, 141.9, 141.7, 131.8, 129.9, 127.4, 127.2, 126.7,
3
): d 8.46 (brs, 1H, NH),
Method A, 7 days, flash chromatography (hexanes/ethyl acetate
1
(
80:20)). Yield: 86%; colorless oil; H NMR (CDCl
3
):
d
8.47 (brs, 1H,
2
13
NH), 7.76 (s, 4H, Ar), 7.26e7.18 (m, 2H, Ar), 7.08 (t, 1H, J ¼ 7.5 Hz, Ar),
3.17e3.07 (m, 1H, CH), 1.07 (d, 6H, J ¼ 6.9 Hz, 2x CH
(CDCl ):
3
7
CH
.00e6.98 (m, 1H, Ar), 3.16e3.06 (m, 1H, CH), 2.38 (t, 2H, J ¼ 7.5 Hz,
3
d
2
), 1.70e1.67 (m, 2H, CH
2
), 1.29e1.28 (m, 4H, 2x CH
2
), 1.40 (d, 6H,
121.9, 119.5, 42.8, 26.7, 23.1; MS (APSIþ) m/z found 368.05;
13
þ
J ¼ 6.8 Hz, 2x CH
3
), 0.86e0.83 (m, 3H, CH
3
); C NMR (CDCl ):
3
C
17
H19ClNO
4
S (M þ H) expected, 368.07.
d
172.8, 146.8, 144.0, 141.7, 129.7, 129.6, 127.5, 127.3, 126.7, 121.8,
1
3
19.2, 37.6, 31.3, 26.7, 25.1, 23.1, 22.4, 13.9; MS (APSIþ) m/z found
5.2.3.22. 2-Iodophenyl 4-(2-chloroacetamido)benzenesulfonate (22).
Method B with potassium carbonate, 5 days, flash chromatography
þ
90.10; C21
H28NO
4
S (M þ H) expected, 390.17.
(
methylene chloride/hexanes (50/50) to methylene chloride/hex-
ꢂ
1
5.2.3.16. 2-Iodophenyl
4-hexanamidobenzenesulfonate
(16).
ane (75:25)). Yield: 73%; white solid; mp: 110e111 C; H NMR
(CDCl ): 8.56 (s, 1H, NH), 7.87e7.85 (m, 2H, Ar), 7.77e7.71 (m, 3H,
Ar), 7.34e7.26 (m, 2H, Ar), 6.98e6.95 (m, 1H, Ar), 4.20 (s, 2H, CH );
164.5, 149.8, 142.5, 140.2, 131.0, 130.3, 129.7,
Method B with triethylamine, 5 days, flash chromatography
3
d
1
(
methylene chloride/hexanes (75:25)). Yield: 63%; colorless oil; H
NMR (CDCl ): 8.21 (s, 1H, NH), 7.82e7.71 (m, 5H, Ar), 7.32e7.26
),
), 0.87e0.84 (m,
172.6, 149.8, 144.2, 140.2, 130.2, 129.6,
2
1
3
3
d
3
C NMR (CDCl ): d
(
1
m, 2H, Ar), 6.97e6.94 (m, 1H, Ar), 2.39 (t, 2H, J ¼ 7.6 Hz, CH
2
128.6, 123.0, 119.6, 90.2, 42.9; MS (APSIþ) m/z found 451.90;
þ
.71e1.67 (m, 2H, CH
2
), 1.30e1.28 (m, 4H, 2x CH
2
C
14
H
12ClINO
4
S (M þ H) expected, 451.92.
13
3
H, CH
3
); C NMR (CDCl ):
3
d
1
29.3, 128.6, 122.9, 119.1, 90.3, 37.7, 31.3, 25.1, 22.4, 13.9; MS (APSIþ)
5.2.3.23. 2-Isopropylphenyl 4-(3-chloropropanamido)benzenesulfo-
nate (23). Method B with potassium carbonate, 3 days, flash
chromatography (hexanes/methylene chloride (50:50) to (20:80)).
þ
m/z found 473.95; C18
H21INO
4
S (M þ H) expected, 474.02.
ꢂ
1
5.2.3.17. 2-Isopropylphenyl 4-isobutyramidobenzenesulfonate (17).
Yield: 52%; white solid; mp: 119e120 C; H NMR (CDCl
7.84e7.82 (m, 2H, Ar), 7.73e7.71 (m, 2H, Ar), 7.60 (brs, 1H, NH),
7.28e7.20 (m, 2H, Ar), 7.13e7.09 (m, 1H, Ar), 7.02e7.00 (m, 1H, Ar),
3.88 (t, 2H, J ¼ 6.3 Hz, CH ), 3.15e3.08 (m, 1H, CH), 2.87 (t, 2H,
J ¼ 6.3 Hz, CH ), 1.07 (d, 6H, J ¼ 6.9 Hz, 2x CH
168.3, 146.9, 142.8, 141.8, 130.9, 129.8, 127.5, 127.3, 126.7, 121.9,
3
):
Method B with triethylamine, 1 day, flash chromatography (hex-
anes/ethyl acetate (90:10)). Yield: 62%; whitish solid; mp:
d
ꢂ
1
1
25e127 C; H NMR (CDCl
H, Ar), 7.54 (brs, 1H, NH), 7.33e7.23 (m, 2H, Ar), 7.18e7.12 (m, 1H,
Ar), 7.05e7.03 (m, 1H, Ar), 3.24e3.15 (m, 1H, CH), 2.64e2.55 (m, 1H,
CH), 1.32 (d, 6H, J ¼ 9.2 Hz, 2xCH ), 1.12 (d, 6H, J ¼ 9.2 Hz, 2x CH );
175.9, 147.0, 143.5, 141.8, 130.2, 129.8, 127.4,
3
):
d
7.87e7.84 (m, 2H, Ar), 7.79e7.76 (m,
2
13
2
2
3 3
); C NMR (CDCl ):
d
3
3
119.4, 40.5, 39.4, 26.8, 23.1; MS (APSIþ) m/z found 382.05; HRMS
13
þ
C NMR (CDCl
3
):
d
(ESI) m/z found 382.0874; C18
382.0881.
H
21ClNO
4
S (M þ H) expected,
1
27.2, 126.7, 121.9, 119.1, 36.8, 26.7, 23.1, 19.4; MS (APSIþ) m/z found
þ
3
62.10; C19
H24NO
4
S (M þ H) expected, 362.14.
5.2.3.24. 2-Iodophenyl
4-(3-chloropropanamido)benzenesulfonate
5.2.3.18. 2-Iodophenyl
4-isobutyramidobenzenesulfonate
(18).
(24). Method B with potassium carbonate, 5 days, flash chroma-
Method B with triethylamine, 5 days, flash chromatography
methylene chloride/hexanes (75:25)). Yield: 84%; orange solid;
tography (methylene chloride/hexanes (75:25) to methylene
ꢂ
1
(
chloride). Yield: 38%; whitish solid; mp: 143e144 C; H NMR
(CDCl ): 7.89e7.86 (m, 2H, Ar), 7.76e7.71 (m, 3H, Ar), 7.55 (s, 1H,
NH), 7.34e7.25 (m, 2H, Ar), 7.01e6.95 (m, 1H, Ar), 3.89 (t, 2H,
ꢂ
1
mp: 106e107 C; H NMR (CDCl
3
):
d
8.10 (s, 1H, NH), 7.82e7.71 (m,
3
d
5
1
H, Ar), 7.32e7.26 (m, 2H, Ar), 6.97e6.94 (m, 1H, Ar), 2.61e2.54 (m,
13
13
H, CH), 1.22 (d, 6H, J ¼ 6.7 Hz, 2x CH
3
); C NMR (CDCl
3
):
d
176.4,
J ¼ 6.3 Hz, CH
2
), 2.87 (t, 2H, J ¼ 6.3 Hz, CH
2 3
); C NMR (CDCl ):
149.8, 144.2, 140.2, 130.2, 129.6, 129.4, 128.6, 122.9, 119.3, 90.3, 36.7,
d
168.2, 150.0, 143.1, 140.2, 130.6, 130.4, 129.6, 128.5, 123.1, 119.3,
þ
1
9.5; MS (APSIþ) m/z found 445.90; C16
H17INO
4
S (M þ H) ex-
90.2, 40.7, 39.4; MS (APSIþ) m/z found 465.90; HRMS (ESI) m/z
þ
pected, 445.99.
found 465.9354; C15
H
14ClINO
4
S (M þ H) expected, 465.9377.
5.2.3.19. 2-Isopropylphenyl 4-pivalamidobenzenesulfonate (19).
5.2.3.25. 2-Isopropylphenyl 4-(4-chlorobutanamido)benzenesulfo-
Method B with triethylamine, 2 days, flash chromatography (hex-
nate (25). Method B with potassium carbonate, 3 days, flash
1
anes/ethyl acetate (80:20)). Yield: 54%; orange oil; H NMR (CDCl
7.75e7.71 (m, 5H, 4x Ar and NH), 7.26e7.17 (m, 2H, Ar), 7.10e7.04
m, 1H, Ar), 6.96e6.94 (m, 1H, Ar), 3.15e3.11 (m, 1H, CH), 1.30 (s, 9H,
3
):
chromatography (hexanes/methylene chloride (50:50)). Yield: 70%;
1
d
brown oil; H NMR (CDCl
3
):
d
8.65e8.56 (brs, 1H, NH), 7.78e7.74
(
3
(m, 4H, Ar), 7.26e7.18 (m, 2H, Ar), 7.10e7.06 (m, 1H, Ar), 7.01e6.99
(m, 1H, Ar), 3.60e3.57 (m, 2H, CH ), 3.13e3.07 (m, 1H, CH), 2.59 (t,
13
x CH
3
), 1.05 (d, 6H, J ¼ 6.9 Hz, 2x CH
3
); C NMR (CDCl
3
):
d
177.2,
2

692
M. Gagn ꢀe -Boulet et al. / European Journal of Medicinal Chemistry 155 (2018) 681e694
2
2
H, J ¼ 7.0 Hz, CH
2
), 2.16e2.12 (m, 2H, CH
2
), 1.03 (d, 6H, J ¼ 6.8 Hz,
3 3
(CDCl /CD OD): d 155.4,149.9, 146.1, 139.9,130.1, 129.3,128.2, 126.5,
1
3
x CH
3
); C NMR (CDCl ): 171.4, 146.8, 143.8, 143.8, 141.7, 129.7,
3
d
122.7, 117.1, 90.1, 34.4, 14.7; MS (APSIþ) m/z found 446.90; HRMS
þ
127.6, 127.3, 126.8, 121.8, 119.3, 44.3, 34.2, 27.7, 26.8, 23.1; MS
(ESI) m/z found 446.9864; C15
446.9876.
H16IN
2
O
4
S (M þ H) expected,
þ
(
APSIþ) m/z found 396.00 C19
H
23ClNO
4
S (M þ H) expected, 396.10.
5.2.3.26. 2-Iodophenyl
4-(4-chlorobutanamido)benzenesulfonate
5.2.5.3. 2-Isopropylphenyl 4-(3-propylureido)benzenesulfonate (29).
(
26). Method B with potassium carbonate, 5 days, flash chroma-
Method C, 1 day, flash chromatography (hexanes to hexanes/ethyl
1
1
tography (methylene chloride). Yield: 79%; orange oil; H NMR
CDCl ): 8.16 (s, 1H, NH), 7.83e7.71 (m, 5H, Ar), 7.34e7.25 (m, 2H,
Ar), 6.99e6.93 (m, 1H, Ar), 3.63 (t, 2H, J ¼ 8.0 Hz, CH ), 2.63e2.58
); C NMR (CDCl ): 171.0,
acetate (80:20)). Yield: 30%; colorless oil; H NMR (CDCl
3
):
d
7.83 (s,
(
3
d
1H, NH), 7.71e7.69 (m, 2H, Ar), 7.53e7.51 (m, 2H, Ar), 7.26e7.18 (m,
2H, Ar), 7.09e7.05 (m, 1H, Ar), 6.99e6.97 (m, 1H, Ar), 5.60 (brs, 1H,
2
13
(
1
3
m, 2H, CH
2
), 2.21e2.12 (m, 2H, CH
2
3
d
NH), 3.19e3.09 (m, 3H, CH and CH
6H, J ¼ 6.9 Hz, 2x CH ), 0.88 (t, 3H, J ¼ 7.4 Hz, CH
(CDCl ): 155.2, 146.8, 145.4, 141.7, 129.8, 127.7, 127.5, 127.3, 126.7,
2 2
), 1.53e1.44 (m, 2H, CH ), 1.05 (d,
1
3
49.8, 143.9, 140.2, 130.3, 129.7, 129.5, 128.7, 122.9, 119.2, 90.3, 44.4,
3
3
); C NMR
þ
4.2, 27.6; MS (APSIþ) m/z found 479.90; C16
H
16ClINO
4
S (M þ H)
3
d
expected, 479.95.
121.8, 117.8, 42.0, 26.7, 23.1, 23.1, 11.3; MS (APSIþ) m/z found 377.10;
þ
HRMS (ESI) m/z found 377.1532; C19
377.1536.
H
25
N
2
O
4
S (M þ H) expected,
5
.2.4. General preparation of compounds 27e38
Method C. The relevant isocyanate was added to a solution of
the appropriate aniline (43 or 44) in acetonitrile (3 mL) with po-
tassium carbonate (1. Eq). The reaction mixture was stirred at room
temperature for 1e2 days. After completion of the reaction, the
solvent was evaporated under reduced pressure, the mixture was
diluted with in AcOEt (10 mL) and was washed successively with
water (10 mL) and brine (10 mL), dried over sodium sulfate, filtered
and evaporated to dryness under reduced pressure. The residue
was purified by flash chromatography on silica gel or by
recrystallization.
5.2.5.4. 2-Iodophenyl 4-(3-propylureido)benzenesulfonate (30).
Method C, 1 day, flash chromatography (hexanes to hexanes/ethyl
ꢂ
1
acetate (80:20)). Yield: 12%; white solid; mp: 101e102 C; H NMR
(CDCl ): 7.97 (s, 1H, NH), 7.77e7.72 (m, 3H, Ar), 7.55e7.52 (m, 2H,
Ar), 7.34e7.25 (m, 2H, Ar), 7.00e6.94 (m, 1H, Ar), 5.83e5.60 (brs,
1H, NH), 3.20 (t, 2H, CH ), 1.57e1.45 (m, 2H, CH ), 0.89 (t, 3H,
); C NMR (CDCl ): 155.3, 149.8, 145.8, 140.2, 130.4,
3
d
2
2
13
J ¼ 9.7 Hz, CH
3
3
d
129.7, 128.7, 127.2, 122.9, 117.9, 90.4, 42.0, 23.2, 11.4; MS (APSIþ) m/z
þ
found 460.90; C16
H18IN
2
O
4
S (M þ H) expected, 461.00.
Method D. The relevant isocyanate was added to a solution of
the appropriate aniline (43 or 44) in acetonitrile (3 mL) with po-
5.2.5.5. 2-Isopropylphenyl 4-(3-pentylureido)benzenesulfonate (31).
tassium carbonate (1. Eq). The reaction mixture was stirred at
Method D, 5 days, flash chromatography (hexanes to hexanes/ethyl
ꢂ
1
100 C for 4e5 days under pressure. After completion of the reac-
acetate (80:20)). Yield: 35%; white sticky solid; H NMR (CDCl
3
):
tion, the solvent was evaporated under reduced pressure, the
mixture was diluted with in AcOEt (10 mL) and was washed suc-
cessively with water (10 mL) and brine (10 mL), dried over sodium
sulfate, filtered and evaporated to dryness under reduced pressure.
The residue was purified by flash chromatography on silica gel.
Method E. The relevant isocyanate was added to a solution of
the appropriate aniline (43 or 44) in acetonitrile (3 mL) with po-
d
7.98 (brs, 1H, NH), 7.71e7.69 (m, 2H, Ar), 7.54e7.52 (m, 2H, Ar),
7.26e7.18 (m, 2H, Ar), 7.09e7.05 (m, 1H, Ar), 6.99e6.97 (m, 1H, Ar),
5.69 (brs, 1H, NH), 3.22e3.09 (m, 3H, CH and CH ), 1.48e1.45 (m,
2H, CH ), 1.31e1.19 (m, 4H, 2x CH ),
), 1.05 (d, 6H, J ¼ 6.8 Hz, 2x CH
0.84e0.81 (m, 3H, CH ); C NMR (CDCl ): 155.3, 146.8, 145.5,
141.7, 129.8, 127.6, 127.5, 127.3, 126.7, 121.8, 117.8, 40.3, 29.6, 29.0,
2
2
2
3
13
3
3
d
26.7, 23.1, 22.3, 14.0; MS (APSIþ) m/z found 405.10; C21
29 2 4
H N O S
þ
tassium carbonate (1. Eq). The reaction mixture was stirred at
(M þ H) expected, 405.18.
ꢂ
1
10 C for 2 h under microwaves. After completion of the reaction,
the solvent was evaporated under reduced pressure, the mixture
was diluted with in AcOEt (10 mL) and was washed successively
with water (10 mL) and brine (10 mL), dried over sodium sulfate,
filtered and evaporated to dryness under reduced pressure. The
residue was purified by flash chromatography on silica gel or by
recrystallization.
5.2.5.6. 2-Iodophenyl
Method D, 5 days, flash chromatography (hexanes to hexanes/ethyl
4-(3-pentylureido)benzenesulfonate
(32).
1
acetate (80:20)). Yield: 56%; white sticky solid; H NMR (CDCl
7.92 (s, 1H, NH), 7.78e7.72 (m, 3H, Ar), 7.56e7.53 (m, 2H, Ar),
7.34e7.25 (m, 2H, Ar), 7.00e6.94 (m,1H, Ar), 5.66 (brs, 1H, NH), 3.23
(t, 2H, J ¼ 7.1 Hz, CH ), 1.53e1.44 (m, 2H, CH ), 1.31e1.24 (m, 4H, 2x
CH ), 0.87e0.82 (m, 3H, CH ); C NMR (CDCl ): 155.2, 149.8,
145.8, 140.2, 130.4, 129.7, 128.7, 127.2, 122.9, 117.8, 90.4, 40.3, 29.6,
3
):
d
2
2
13
2
3
3
d
5
5
.2.5. Characterization of compounds 27e38
.2.5.1. 2-Isopropylphenyl 4-(3-ethylureido)benzenesulfonate (27).
29.0, 22.4, 14.0; MS (APSIþ) m/z found 489.00; C18
2 4
H22IN O S
þ
Method C, 2 days, flash chromatography (hexanes/ethyl acetate
(M þ H) expected, 489.03.
ꢂ
1
(
d
90:10)). Yield: 39%; white solid; mp: 141e142 C; H NMR (CDCl
8.06e8.01 (m, 1H, NH), 7.71e7.69 (m, 2H, Ar), 7.53e7.51 (m, 2H,
Ar), 7.26e7.18 (m, 2H, Ar), 7.09e7.05 (m, 1H, Ar), 6.99e6.97 (m, 1H,
Ar), 5.69 (brs, 1H, NH), 3.29e3.21 (m, 2H, CH ), 3.15e3.08 (m, 1H,
CH), 1.09 (t, 3H, J ¼ 7.2 Hz, CH ), 1.04 (d, 6H, J ¼ 6.8 Hz, 2x CH
NMR (CDCl ): 155.2, 146.8, 145.5, 141.7, 129.8, 127.6, 127.5, 127.3,
3
):
5.2.5.7. 2-Isopropylphenyl 4-(3-(3-chloropropyl)ureido)benzenesul-
fonate (33). Method D, 4 days, flash chromatography (hexanes/
ꢂ
2
ethyl acetate (75:25)). Yield: 75%; whitish solid; mp: 115e117 C;
1
3
1
3
3
);
C
3
H NMR (CDCl ): d 7.73e7.71 (m, 2H, Ar), 7.52e7.50 (m, 2H, Ar), 7.41
3
d
(brs,1H, NH), 7.26e7.19 (m, 2H, Ar), 7.11e7.07 (m, 1H, Ar), 7.00e6.98
(m, 1H, Ar), 5.43e5.41 (m, 1H, NH), 3.59 (t, 2H, J ¼ 6.0 Hz, CH ),
3.44e3.39 (m, 2H, CH ), 3.17e3.10 (m, 1H, CH), 2.02e1.96 (m, 2H,
CH
), 1.06 (d, 6H, J ¼ 6.8 Hz, 2x CH
46.9, 145.1, 141.7, 129.8, 128.0, 127.5, 127.3, 126.7, 121.8, 117.9, 42.4,
1
3
26.7, 121.8, 117.8, 35.0, 26.7, 23.1, 15.1; MS (APSIþ) m/z found
2
þ
63.10; HRMS (ESI) m/z found 363.1374; C18
23
H N
2
O
4
S (M þ H)
2
13
expected, 363.1379.
2
3 3
); C NMR (CDCl ): d 154.8,
1
5
.2.5.2. 2-Iodophenyl
4-(3-ethylureido)benzenesulfonate
(28).
37.6, 32.3, 26.7, 23.1; MS (APSIþ) m/z found 411.10; HRMS (ESI) m/z
þ
Method C, 1 day, multi-solvent recrystallization (ethyl acetate/
hexanes until precipitation). Yield: 18%; white solid; mp:
found 411.1144; C19
H24ClN
2
O
4
S (M þ H) expected, 411.1146.
ꢂ
1
130e131 C; H NMR (CDCl
3
/CD
3
OD):
d
7.60e7.54 (m, 3H, Ar),
5.2.5.8. 2-Iodophenyl 4-(3-(3-chloropropyl)ureido)benzenesulfonate
7
.41e7.37 (m, 2H, Ar), 7.18e7.08 (m, 2H, Ar), 6.83e6.78 (m, 1H, Ar),
(34). Method C, 2 days, flash chromatography (hexanes/ethyl ace-
13
1
3
.07 (q, 2H, J ¼ 7.2 Hz, CH
2
), 0.98 (t, 3H, J ¼ 7.2 Hz, CH
3
); C NMR
tate (80:20)). Yield: 22%; colorless oil; H NMR (CDCl
3
):
d
8.03 (s,

M. Gagn ꢀe -Boulet et al. / European Journal of Medicinal Chemistry 155 (2018) 681e694
693
1
2
2
d
H, NH), 7.74e7.70 (m, 3H, Ar), 7.53e7.50 (m, 2H, Ar), 7.32e7.21 (m,
H, Ar), 6.98e6.92 (m, 1H, Ar), 3.56 (t, 2H, J ¼ 6.2 Hz, CH ), 3.39 (t,
); C NMR (CDCl ):
acetate (90:10)). Yield: 66%; pale yellow oil; 1H NMR (CDCl
8.75e8.74 (m, 1H, Ar), 8.56e8.52 (m, 1H, Ar), 8.24e8.20 (m, 1H,
3
):
2
d
13
H, J ¼ 6.5 Hz, CH
2
), 2.00e1.92 (m, 2H, CH
2
3
Ar), 7.82e7.77 (m, 1H, Ar), 7.32e7.24 (m, 2H, Ar), 7.18e7.13 (m, 1H,
Ar), 7.04e7.02 (m, 1H, Ar), 3.16e3.02 (m, 1H, CH), 1.08 (d, 6H,
155.3, 149.7, 145.6, 140.2, 130.3, 129.7, 128.7, 127.3, 122.8, 118.0,
1
3
9
0.4, 42.4, 37.5, 32.3; MS (APSIþ) m/z found 494.95; HRMS (ESI) m/z
J ¼ 6.9 Hz, 2x CH
3 3
); C NMR (CDCl ): d 148.2, 146.6, 141.5, 138.1,
þ
found 494.9624; C16
H17ClIN
2
O
4
S (M þ H) expected, 494.9643.
133.8, 130.8, 128.6, 128.0, 127.6, 127.0, 123.6, 121.7, 26.9, 23.1.
5.2.5.9. 2-Iodophenyl 4-(3-cyclopropylureido)benzenesulfonate (35).
5.2.7.2. 2-Isopropylphenyl 4-nitrobenzenesulfonate (40). Ethyl ace-
Method D, 4 days, flash chromatography (methylene chloride).
tate, 2 days, recrystallization in ethanol. Yield: 85%; white solid;
1
ꢂ
1
Yield: 27%; colorless oil; H NMR (CDCl
3
):
d
7.82e7.74 (m, 3H, Ar),
mp: 101e103 C; H NMR (CDCl ): d 8.42e8.37 (m, 2H, Ar),
3
7.63e7.56 (m, 3H, Ar and NH), 7.37e7.30 (m, 2H, Ar), 7.01e6.95 (m,
8.12e8.08 (m, 2H, Ar), 7.32e7.23 (m, 2H, Ar), 7.17e7.11 (m, 1H, Ar),
1
H, Ar), 2.66e2.60 (m, 1H, CH), 0.90e0.83 (m, 2H, CH
2
), 0.69e0.63
7.01e6.97 (m, 1H, Ar), 3.15e3.01 (m, 1H, CH), 1.08 (d, 6H, J ¼ 6.9 Hz,
13
13
(
m, 2H, CH
2
); C NMR (CDCl
3
):
d
156.6, 149.9, 145.8, 140.0, 130.2,
2x CH
3
); C NMR (CDCl
3
):
d
150.9, 146.7, 141.7, 141.6, 129.8, 127.9,
1
29.5, 128.4, 127.0, 122.8, 117.5, 90.2, 22.2, 6.6; MS (APSIþ) m/z
127.6, 127.0, 124.4, 121.7, 26.9, 23.1.
þ
found 458.95; C16
H16IN
2
O
4
S (M þ H) expected, 458.99.
5.2.7.3. 2-Iodophenyl 4-nitrobenzenesulfonate (41). Methylene
5
.2.5.10. 2-Isopropylphenyl 4-(3-cyclopentylureido)benzenesulfonate
chloride, 1 day, flash chromatography (hexanes/ethyl acetate
ꢂ
1
(36). Method E, 2 h, flash chromatography (hexanes/ethyl acetate
(95:5)). Yield: 68%; white solid; mp: 108e110 C; H NMR (CDCl
3
3
):
):
1
(
90:10)). Yield: 9%; colorless oil; H NMR (CDCl
H, Ar), 7.53e7.50 (m, 2H, Ar), 7.46 (brs, 1H, NH), 7.28e7.18 (m, 2H,
Ar), 7.11e7.05 (m, 1H, Ar), 6.99e6.96 (m, 1H, Ar), 4.13e4.04 (m, 1H,
CH), 3.18e3.09 (m, 1H, CH), 2.01e1.89 (m, 2H, CH ), 1.66e1.54 (m,
H, 2x CH ), 1.44e1.35 (m, 2H, CH );
), 1.05 (d, 6H, J ¼ 6.9 Hz, 2x CH
C NMR (CDCl ): 154.4, 146.9, 145.3, 141.8, 129.8, 127.8, 127.5,
3
):
d
7.72e7.69 (m,
d
8.40e8.38 (m, 2H, Ar), 8.14e8.12 (m, 2H, Ar), 7.78e7.76 (m, 1H,
13
2
Ar), 7.41e7.40 (m, 2H, Ar), 7.05e7.02 (m, 1H, Ar); C NMR (CDCl
151.2149.5, 141.3, 140.3, 130.3, 129.9, 129.1, 124.4, 123.2, 89.6.
d
2
4
2
2
3
5.2.8. General preparation of compounds 42e44
1
3
3
d
The relevant phenyl nitrobenzenesulfonate 39e41 was added to
a solution of iron powder (6 Eq) and concentrated hydrochloric acid
(1 mL) in a mixture of ethanol 95% and water (10:1, 150 mL). The
reaction mixture was reflux 1 day. After completion of the reaction,
the solvent was evaporated under reduced pressure, the mixture
was diluted in AcOEt (75 mL) and was washed successively with a
saturated solution of sodium bicarbonate (75 mL) and brine
(75 mL), dried over sodium sulfate, filtered and evaporated to
dryness under reduced pressure. The residue was purified by flash
chromatography on silica gel or by recrystallization in methylene
chloride.
1
27.3, 126.7, 121.9, 117.8, 52.1, 33.3, 26.7, 23.5, 23.1; MS (APSIþ) m/z
þ
found 403.10; C21
H N
27 2
O
4
S (M þ H) expected, 403.17.
5
.2.5.11. 2-Isopropylphenyl 4-(3-(cyclopentylmethyl)ureido)benze-
nesulfonate (37). Method E, 2 h, flash chromatography (hexanes/
1
ethyl acetate (85:15)). Yield: 16%; colorless oil; H NMR (CDCl
7.73e7.70 (m, 2H, Ar), 7.53e7.50 (m, 2H, Ar), 7.28e7.18 (m, 3H, Ar
and NH), 7.12e7.06 (m, 1H, Ar), 7.00e6.97 (m, 1H, Ar), 3.19e3.09 (m,
H, CH and CH ), 2.07e1.97 (m, 1H, CH), 1.78e1.68 (m, 2H, CH ),
), 1.25e1.11 (m, 2H, CH ), 1.06 (d, 6H,
); C NMR (CDCl ): 154.7, 146.9, 145.1, 141.8,
3
):
d
3
2
2
1.63e1.50 (m, 4H, 2x CH
2
2
13
J ¼ 6.9 Hz, 2x CH
3
3
d
129.8, 128.0, 127.4, 127.2, 126.7, 121.9, 117.9, 45.3, 39.9, 30.3, 26.7,
5.2.9. Characterization of compounds 42e44
þ
2
5.2, 23.1; MS (APSIþ) m/z found 417.10; C22
29
H N
2
O
4
S (M þ H)
5.2.9.1. 2-Isopropylphenyl
3-aminobenzenesulfonate
(42).
expected, 417.18.
Method A, 1 day, flash chromatography (hexanes/ethyl acetate
ꢂ
1
(
95:5)). Yield: 68%; pale solid; mp: 87e89 C; H NMR (CDCl
3
):
5.2.5.12. 2-Iodophenyl 4-(3-(cyclopentylmethyl)ureido)benzenesul-
d
7.30e7.19 (m, 4H, Ar), 7.14e7.02 (m, 3H, Ar), 6.92e6.88 (m,1H, Ar),
fonate (38). Method E, 2 h, multi-solvent recrystallization (methy-
3.93 (brs, 2H, NH
2
), 3.21e3.07 (m, 1H, CH), 1.07 (d, 6H, J ¼ 6.9 Hz, 2x
): 147.2, 147.1, 141.8, 136.9, 130.0, 127.2, 127.1,
126.6, 122.0, 120.0, 117.8, 113.7, 26.6, 23.1.
13
lene chloride/hexanes until precipitation). Yield: 7%; colorless oil;
CH
3
); C NMR (CDCl
3
d
1
H NMR (CD
.41e7.29 (m, 2H, Ar), 7.04e6.99 (m, 1H, Ar), 3.14 (d, 2H, J ¼ 7.2 Hz,
CH ), 2.13e2.03 (m, 1H, CH), 1.84e1.73 (m, 2H, CH ), 1.70e1.55 (m,
H, 2x CH ); C NMR (CD OD): 155.8,
50.2, 146.3, 140.0, 130.0, 129.3, 128.1, 126.9, 122.6, 117.1, 89.8, 44.3,
3
OD): d 7.81e7.71 (m, 3H, Ar), 7.59e7.55 (m, 2H, Ar),
7
2
2
5.2.9.2. 2-Isopropylphenyl
Method A, 1 day, flash chromatography (hexanes/methylene chlo-
4-aminobenzenesulfonate
(43).
13
4
1
2
), 1.31e1.22 (m, 2H, CH
2
3
d
ꢂ
1
ride (70:30)). Yield: 96%; pale orange solid; mp: 108e112 C;
NMR (CDCl ): 7.60e7.57 (m, 2H, Ar), 7.27e7.12 (m, 2H, Ar),
7.13e7.03 (m, 2H, Ar), 6.66e6.63 (m, 2H, Ar), 4.31 (brs, 2H, NH ),
); C NMR
151.8, 147.1, 141.9, 130.6, 127.1, 127.0, 126.5, 123.4, 122.2,
114.0, 26.6, 23.1.
H
3
9.9, 29.8, 24.8; MS (APSIþ) m/z found 500.95; C19
H22IN
2
O
4
S
3
d
þ
(
M
þ H) expected, 501.03.
2
13
3
.20e3.11 (m, 1H, CH), 1.06 (d, 6H, J ¼ 6.9 Hz, 2x CH
3
5.2.6. General preparation of compounds 39e41
(CDCl ):
3
d
The relevant 2-iodophenol or 2-isopropylphenol was added to a
solution of a 3- or 4-nitrobenzenesulfonyl chloride in ethyl acetate
or methylene chloride (50 mL) in presence of triethylamine (1.5 Eq).
The reaction mixture was stirred at room temperature for 1e2 days.
After completion of the reaction, the solvent was evaporated under
reduced pressure, the mixture was diluted in AcOEt (50 mL) and
was washed successively with water (50 mL) and brine (50 mL),
dried over sodium sulfate, filtered and evaporated to dryness under
reduced pressure. The residue was purified by recrystallization or
by flash chromatography on silica gel.
5.2.9.3. 2-Iodophenyl 4-aminobenzenesulfonate (44). Method A, 1
day, recrystallization in methylene chloride. Yield: 51%; white solid;
ꢂ
1
mp: 109e111 C; H NMR (DMSO‑d
6
): d 7.80e7.78 (m, 1H, Ar),
7.42e7.34 (m, 3H, Ar), 7.13e7.11 (m, 1H, Ar), 7.02e6.98 (m, 1H, Ar),
13
6.58e6.56 (m, 2H, Ar), 6.38 (brs, 2H, NH
2 3
); C NMR (CDCl ):
d
155.3, 150.2, 140.3, 131.1, 130.1, 129.0, 122.8, 118.4, 113.1, 92.2.
5.3. SwissADME web tool
5
5
.2.7. Characterization of compounds 39e41
.2.7.1. 2-Isopropylphenyl 3-nitrobenzenesulfonate
The free web-based SwissADME tool [24] was used to calculate
and predict the physicochemical, pharmacokinetics, drug-likeness
and medicinal chemistry properties of PAB-SOs and PUB-SOs 11,
(39).
Methylene chloride, 1 day, flash chromatography (hexanes/ethyl

694
M. Gagn ꢀe -Boulet et al. / European Journal of Medicinal Chemistry 155 (2018) 681e694
1
2,13,14,19, 23, 24, 27, 28, 30, 33 and 34. The chemical structures of
Chem. Res. Toxicol. 25 (2012) 1176e1191.
13] D. Thaens, D. Heinzelmann, A. Bohme, A. Paschke, G. Schuurmann, Chemo-
assay screening of DNA-reactive mutagenicity with 4-(4-nitrobenzyl)pyridine
[
[
PAB-SO and PUB-SO derivatives were drawn, translated to simplify
molecular input line entry specification (SMILES) and analyzed by
the SwissADME tool. Briefly, TPSA is calculated from Ertl et al. [25].
The CLogP is the average of 5 predictions (iLOGP [26], XLOGP3 [27],
WLOGP [28], MLOGP [29e31] and Silicos-IT LogP [32]). The topo-
logical Ali LogS was calculated from Ali et al. method [33]. GIA and
blood-brain barrier permeability (BBBP) were calculated according
to BOILED-Egg model while p-glycoprotein substrate was predicted
using support vector machines model (SVM). Drug-likeness pre-
dictions were implemented from Lipinski (Pfizer) [31], Ghose [34],
Veber (GSK) [35], Egan (Pharmacia) [36] and Muegge (Bayer) [37]
filters.
-
application to epoxides, oxetanes, and sulfur heterocycles, Chem. Res. Tox-
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Acknowledgments
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This work was supported by grants from CHU de Quebec
Research Center and Natural Sciences and Engineering Research
Council of Canada (NSERC, RGPIN-2016-05069). M. Gagn eꢀ -Boulet is
the recipient of studentships from the Fonds de Recherche du
Qu eꢀ bec - Sant eꢀ and from Fonds d'enseignement et de recherche of
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Appendix A. Supplementary data
Supplementary data related to this article can be found at
https://doi.org/10.1016/j.ejmech.2018.06.030.
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