Synthesis and prostaglandin synthase inhibitory activity of new aromatic O-alkyloxime ethers substituted with methylsulfonamido or methylsulfonyl groups on their aliphatic portion

Article abstract of DOI:10.1016/S0014-827X(03)00110-1

Some aromatic O-alkyloxime ethers substituted with methylsulfonamido (7) or methylsulfonyl (8) groups on their aliphatic portions were prepared as analogues of structurally related cyclooxygenase (COX) inhibitors (6) bearing a carboxylic group typical of the classic non-steroidal anti-inflammatory drugs (NSAIDs) in the place of the sulfurated moiety. In addition, also analogues of compounds 8 in which the aliphatic chain is further lengthened by 1 (9), 2 (10), or 3 (11) carbon atoms were synthesized. All compounds (7-11) were tested in vitro towards COX2, and compounds 7-9 towards COX1, by measuring prostaglandin E2 (PGE₂) production in activated J774.2 macrophages and U937 cell lines, respectively. While all new compounds were found to possess little or no activity on the COX2 isoenzyme, some of these (7a-7d, 8a, 8d, 9e and 9f) appeared to possess an appreciable activity on COX1, with % inhibition values at a concentration of 1 μM ranging from 30% of 8a to 76% of 9e. The COX1 selectivity of the new compounds was tentatively explained by means of a docking study of one of the more active compounds tested on both COX isoenzymes (7d), which indicated a different number of hydrogen bonding interactions with the Arg120 of the active sites of the two enzymes, and therefore, an energetically favored interaction (3.5 kcal/mol) with COX1, compared with COX2.

Full text of DOI:10.1016/S0014-827X(03)00110-1

Il Farmaco 58 (2003) 707Á714
/
www.elsevier.com/locate/farmac
Synthesis and prostaglandin synthase inhibitory activity of new
aromatic O-alkyloxime ethers substituted with methylsulfonamido or
methylsulfonyl groups on their aliphatic portion
Aldo Balsamo a,*, Francesca Mancini b, Claudio Milanese b, Elisabetta Orlandini a,
Gabriella Ortore a, Mario Pinza b, Simona Rapposelli a, Armando Rossello a
a Facolta` di Farmacia, Dipartimento di Scienze Farmaceutiche, Universita` di Pisa, Via Bonanno 6, 56100 Pisa, Italy
b ACRAF, Angelini Ricerche, 00040 S. Palomba, Pomezia, Rome, Italy
Received 12 November 2002; accepted 4 February 2003
Abstract
Some aromatic O-alkyloxime ethers substituted with methylsulfonamido (7) or methylsulfonyl (8) groups on their aliphatic
portions were prepared as analogues of structurally related cyclooxygenase (COX) inhibitors (6) bearing a carboxylic group typical
of the classic non-steroidal anti-inflammatory drugs (NSAIDs) in the place of the sulfurated moiety. In addition, also analogues of
compounds 8 in which the aliphatic chain is further lengthened by 1 (9), 2 (10), or 3 (11) carbon atoms were synthesized. All
compounds (7Á
production in activated J774.2 macrophages and U937 cell lines, respectively. While all new compounds were found to possess little
or no activity on the COX2 isoenzyme, some of these (7aÁ7d, 8a, 8d, 9e and 9f) appeared to possess an appreciable activity on
/
11) were tested in vitro towards COX2, and compounds 7Á9 towards COX1, by measuring prostaglandin E2 (PGE2)
/
/
COX1, with % inhibition values at a concentration of 1 mM ranging from 30% of 8a to 76% of 9e. The COX1 selectivity of the new
compounds was tentatively explained by means of a docking study of one of the more active compounds tested on both COX
isoenzymes (7d), which indicated a different number of hydrogen bonding interactions with the Arg120 of the active sites of the two
enzymes, and therefore, an energetically favored interaction (3.5 kcal/mol) with COX1, compared with COX2.
´
# 2003 Editions scientifiques et me´dicales Elsevier SAS. All rights reserved.
Keywords: NSAIDs; Ciclooxygenase inhibitors; Anti-inflammatory drugs; Methylsulfonyl inhibitors; Methylsulfonamido inhibitors
1. Introduction
Most non-steroidal
selective inhibitors of both constitutive (COX1) and
inducible (COX2) cyclooxygenase. The typical side-
effect of these NSAIDs consists of gastrointestinal
damage, commonly attributed to their lack of COX2
selectivity [8,9]. Only a few anti-inflammatory drugs,
such as nimesulide (3) [10], and more recently tricyclic
compounds such as, for example, celecoxib (4) [11] and
rofecoxib (5) [12], have proved to possess a more or less
appreciable selectivity towards COX2 (Fig. 1).
anti-inflammatory
drugs
(NSAIDs) act through the inhibition of prostaglandin
synthase (cyclooxygenase, COX) [1,2]. This enzyme
exists as two isoforms, known as COX1 and COX2.
The COX1 isoform is constitutively expressed in most
tissues and is involved in the physiological production of
prostaglandins, which are gastric cytoprotective agents.
On the contrary, the COX2 isoform is induced by some
Unlike the case of classic non-selective NSAIDs,
which include in their structures a carboxylic function,
of the inflammation mediators [3Á8].
/
Most NSAIDs in current use belong to the class of
arylacetic (1) or arylpropionic acids (2), and are not
in the selective drugs 3Á5, one of their two aryl groups is
substituted by a sulfurated moiety, such as the sulfona-
midic one of 3 and 4, or the methylsulfonic one of 5.
/
Pending an unequivocable definition of the structureÁ
activity relationships in the field of these drugs, it may
/
* Correspondence and reprints.
E-mail address: balsamo@farm.unipi.it (A. Balsamo).
´
0014-827X/03/$ - see front matter # 2003 Editions scientifiques et me´dicales Elsevier SAS. All rights reserved.
doi:10.1016/S0014-827X(03)00110-1

708
A. Balsamo et al. / Il Farmaco 58 (2003) 707Á714
/
Fig. 1. General structures of non-selective arylacetic (1) or arylpropionic acids (2) and formulas of selective COX2 inhibitors (3-5).
be reasonable to attribute the COX2 selectivity of
compounds 3Á5, among other molecular factors, to
compounds 3Á5, (Fig. 1) may confer a COX2 selectivity
/
/
on molecules that are potentially capable of interacting
with COXs, we synthesized some compounds of types 7
and 8, (Fig. 2) which may be viewed as analogues of
anti-inflammatory drugs of type 6, in which the
carboxylic function typical of the classic NSAIDs 1
and 2 is replaced by the methylsulfonamido or methyl-
sulfonyl moiety, respectively. In addition, we also
the presence of these groups in their structures. This
hypothesis appears to be supported by X-ray [13] and
docking studies [14] of the interaction with COX2 of
some of these selective inhibitors bearing the sulfurated
moiety in the highest oxidation state, which indicate the
presence of a strong hydrogen-bonding interaction
between this moiety and the Arg513 of the enzyme
active site.
In previous papers of ours [15,16], we described a
series of substituted 3-(E)-benzylideneaminoxypropio-
nic acids of type 6, designed as analogues of arylacetic
NSAIDs of type 1, in which the aryl moiety is
synthesized compounds of types 9Á11, which are
/
analogues of compounds 8, in which the ethylenic spacer
between the aminoxy portion and the methylsulfonyl
group is further lengthened by 1, 2, or 3 carbon atoms,
respectively.
substituted by
a methyleneaminoxymethyl group.
Some of these compounds, assayed in vivo for their
anti-inflammatory activity by the carrageenan-induced
paw edema test in rats, proved to possess an appreciable
activity. The in vitro tests carried out on COX1 and
COX2 enzymes for 6a and 6b showed that these
compounds possess a certain inhibitory activity towards
both enzyme isoforms (unpublished data) (Fig. 2).
On the basis of these results, bearing in mind the
possibility that sulfurated groups, like those present in
2. Chemistry
Compounds 7aÁ7c were prepared as described in
/
Scheme 1, starting from the appropriate substituted E-
benzylaldoximes 12, which were transformed into their
sodium salt by treatment with EtONa, and were then
allowed to react with 2-chloroethylamine to yield the
corresponding substituted 2-benzylideneaminoxyethyla-
mine derivatives 13aÁ
/
13c. Reaction of 13aÁ13c with
/
Fig. 2. General structures of 3-(E)-benzylideneaminoxypropionic acids (6) and their methylsulfonamido- (7) and methylsulfonyl (8-11) analogues.

A. Balsamo et al. / Il Farmaco 58 (2003) 707Á
/
714
709
Scheme 1.
mesylchloride in the presence of triethylamine afforded
the final methylsulfonamides 7aÁ7c, which were purified
for one of the more active compounds of type 6 (6b) and
celecoxib (4), chosen as a reference drug.
/
by column chromatography on silica gel. Compound 7d
was directly obtained by reaction of the sodium salt of
the 4-fluorobenzaldoxime with 2-[(methanesulfonyl)a-
mino]-1-methanesulfonylethane.
Table 1
In vitro inhibitory activity of methylsulfonamido- (7) and methysulfo-
nyl- (8Á11) alkyloxime ethers towards COX1 and COX2
/
The methylsulfonyl derivatives 8Á11 were synthesized
/
starting from the sodium salt of the appropriate oxime
of type 12, which were treated with 2-chloroethyl-1-
Compound
R
Cyclooxygenase inhibitory activity (%
inhibition)a at a dose of 1 mM
tolylsulfonate, in the case of the preparation of 14aÁ14f,
/
COX1
COX2
or with 3-chloro-1-bromopropane, 4-chloro-1-bromo-
butane or 5-chloro-1-bromopentane in the case of the
preparation of compounds of type 15, 16, 17, respec-
7a
7b
7c
7d
H
50
48
54
53
2
12
6
p-Cl
o-Cl
p-F
tively. The displacement of the chlorine atom of 14Á
with sodium methanesulfinate afforded the crude
methylsulfones 8Á11, which were purified by crystal-
lization from the proper solvent.
The configuration around the CÄ
the intermediates 13Á17 and of the final products 7Á
/
17
6
8a
8b
8c
8d
8e
8f
H
30
18
0
6
8
/
p-Cl
o-Cl
p-F
m-F
0
/N double bond of
33
0
0
13
15
/
/
11
3,4-OCH2OÃ
/
0
was assigned on the basis of the knowledge of the
configuration of the starting benzaldoximes (E), and of
the chemical shift of the proton linked to the oximic
carbon, which is in accordance with the syn relationship
with the oximic oxygen [17].
9a
9b
9d
9e
9f
H
21
15
0
19
19
6
p-Cl
p-F
m-F
76
40
34
19
3,4-OCH2OÃ
/
10a
10b
10d
10e
10f
H
nt
nt
nt
nt
nt
0
5
0
6
0
p-Cl
p-F
m-F
3. Biological studies
3,4-OCH2OÃ
/
11a
11b
11f
H
p-Cl
nt
nt
nt
4
0
The in vitro inhibitory activity towards the COX1 and
COX2 enzymes of compounds 7Á11 was evaluated at a
/
3,4-OCH2OÃ
/
14
dose of 1 mM by measuring prostaglandin E2 (PGE2)
production in U937 cell lines for COX1 and activated
J774.2 macrophages for COX2. Results are reported in
Table 1, together with those obtained in the same tests
6b
p-Cl
38
5
30
66
Celecoxib (4)
a
S.E.M. was lower than 10% in all experiments. nt, not tested.

710
A. Balsamo et al. / Il Farmaco 58 (2003) 707Á714
/
4. Results and discussion
COX1 and COX2 isoenzymes was evaluated (see Fig. 3c
and d, respectively), using the same computational
methods utilized for 7d [18]. As expected, in the COX2
active site (Fig. 3d) the sulfonamidic group of celecoxib
As far as the COX2 enzyme is concerned, only the
methylsulfonyl compound 9e proved to possess an
activity slightly higher than that of the carboxylic
compound 6b, with a percentage inhibition value of
34% vs 30% of 6b. The other new compounds, both of
˚
is oriented towards Arg513, at a distance of 2.80 A,
compatible with the existence of a strong hydrogen
bond; in the docking of celecoxib with COX1 active site
(see Fig. 3c) this group interacts with Arg120.
the methylsulfonamidic (7) and methylsulfonic (8Á11)
/
types, proved to be scarcely active (7b, 8e, 8f, 9a, 9b and
9f), with percentage inhibition values lower than 20%, or
The practical result of this work consists in the
recognition of certain preferential COX1 inhibitors
which, even if unsuitable for therapeutic use, may be
utilized in biopharmacological studies. In addition, this
work suggests that the preference or selectivity towards
the COX2 isoenzyme of methylsulfonamidic or methyl-
sulfonic NSAIDs such as nimesulide or celecoxib does
not depend solely on the presence of these moieties in
their molecular structures, but also on the fact that they
possess an overall molecular profile which allows these
groups to occupy a spatial position, during the interac-
tion of the inhibitor with the enzyme catalytic site, which
permits interactions with amino acidic residues specific
for the COX2 active site.
practically inactive (7a, 7c, 7d, 8aÁ
10f, 11a, 11b and 11f).
As it regards the COX1 enzyme, all the methylsulfo-
namidic compounds 7aÁ7d exhibited a good activity,
/
8d, 9d, 10a, 10b, 10dÁ
/
/
with percentage inhibition values ranging from 48% of
7b to 54% of 7c; on the contrary, among the methylsul-
fonyl derivatives (8, 9), only 9e and 9f proved to possess
a significant activity (percent inhibition values of 76 and
40%, respectively), while the other compounds were
scarcely active (8a, 8b, 8d, 9a and 9b) or completely
inactive (8c, 8e, 8f and 9d). Further research into the
COX-inhibitory properties of the new compounds did
not appear to be justifiable, considering their lack of any
appreciable activity or selectivity towards COX2, which
is the real target of an NSAID.
5. Experimental
In order to suggest a rationalization of these results, a
docking study was performed between 7d, one of the
most active compounds towards COX1 but practically
inactive at the level of the COX2, and both COX
isoenzymes. Fig. 3 illustrates the results obtained using
the MACROMODEL program [18]. As it can be seen, the
docking of 7d with the active site of COX1 (a) and
COX2 (b) appears to be very similar, with the methyl-
sulfonamidic portion oriented in both cases towards
Arg120. Furthermore, while in the COX1 site both
oxygen atoms of the sulfonyl moiety of 7d are at
5.1. Chemistry
Melting points were determined on a Kofler hot stage
1
apparatus and are uncorrected. H NMR spectra of all
compounds were obtained with a Varian Gemini 200
instrument operating at 200 MHz, in a ca. 2% solution
of CDCl3. Analytical TLCs were carried out on 0.25 mm
layer silica gel plates containing a fluorescent indicator;
spots were detected under UV light (254 nm). Column
chromatography was performed using 70Á230-mesh
/
˚
distances (2.8 and 2.6 A) compatible with the existence
of two hydrogen bonds with the Arg120, in the COX2
site, only one of the two sulfonyl oxygens is at a distance
silica gel. Mass spectra were detected with HP-5988 A
spectrometer (EI, 70 eV). Evaporations were made in
vacuo (rotating evaporator). The not commercially
available oximes used for the preparation of compounds
13, 14, 15, 16 and 17 were synthesized as described in
Ref. [19]. Na2SO4 was always used as the drying agent.
Elemental analyses were performed in our analytical
laboratory and agreed with the theoretical values to
˚
from the Arg120 (2.9 A vs 5.8 of the other oxygen)
which permits the formation of a hydrogen bond. In
addition, the docking of 7d with COX2 does not present
any interactions between the sulfonyl group and
Arg513, which are typical of some selective COX2
inhibitors [13,14]. Also, a comparison of the overall
interaction energy of 7d involving the Arg120 residue of
the two isoenzymes, indicates a more favorable interac-
within 90.4%.
/
5.1.1. Preparation of substituted 2-
(benzylideneaminoxy)-ethylamines hydrochlorides (13aÁ
13c×HCl)
A stirred solution of the sodium salt of the appro-
priate oxime (12aÁ12c), prepared by refluxing the oxime
tion (DEꢀ
/
3.5 kcal/mol) for COX1 than for COX2. A
/
possible explanation of this result may be found in the
presence in the COX2 site of an ionic interaction chain
/
between Arg513Á
/
Glu524Á/Arg120 which causes this last
/
amino acid to be less available to act as a hydrogen
bond donor towards the ligand 7d.
With the aim of confirm the validity of the results
obtained by theoretical way for 7d, also the docking of
the COX2 selective inhibitor celecoxib (4) with both
(1.42 mmol) with EtONa (2.84 mmol) in anhydrous
EtOH (14 ml), was treated dropwise with a solution of 2-
chloroethylamine hydrochloride (1.42 mmol) in anhy-
drous EtOH (5 ml). When the addition was complete the
reaction mixture was refluxed for 6 h, cooled, filtered

A. Balsamo et al. / Il Farmaco 58 (2003) 707Á
/
714
711
Fig. 3. Docking interactions between compound 7d or celecoxib 4 and the catalytic site of COX1 (a, c) and COX2 (b, d), respectively.
and evaporated. The residue was take up with Et2O,
treated with an excess of Et2O×HCl to yield crude 13aÁ
13c [20], as hydrochlorides, which were purified by,
crystallization from MeOH/Et2O. 13a×HCl (15%): m.p.
124Á 5.0 Hz), 4.40 (t,
125 8C; 1H NMR d 3.50 (t, 2H, Jꢀ
2H, Jꢀ5.0 Hz), 7.30Á7.81 (m, 5H) and 8.31 ppm (s,
1H). Anal. C9H12N2O×HCl (C, H, N). 13b×HCl (20%):
185 8C; H NMR d 3.40 (t, 2H, Jꢀ5.0 Hz),
4.40 (t, 2H, Jꢀ5.0 Hz), 7.40 (d, 2H, Jꢀ8.0 Hz), 7.61 (d,
2H, Jꢀ8.0 Hz) and 8.30 ppm (s, 1H). Anal.
C9H11ClN2O×HCl (C, H, N). 13c×HCl (35%): m.p.
114 8C; H NMR d 3.59 (t, 2H, Jꢀ5.0 Hz), 4.50
(t, 2H, Jꢀ
1H). Anal. C9H11ClN2O×
/
5.0 Hz), 7.30Á
/
8.00 (m, 4H) and 8.60 ppm (s,
HCl (C, H, N).
/
/
/
/
5.1.2. Preparation of substituted N-(2-
(benzylideneaminoxy)ethyl)-methanesulfonamides 7aÁ
A solution of methanesulfonylchloride (1.38 mmol) in
Et2O (10 ml) was added dropwise to a solution of the
appropriate oxime ether 13aÁ13c (1.38 mmol) and NEt3
(6.46 mmol) in Et2O (10 ml). The mixture was stirred at
room temperature for 1 h, and the resulting suspension
was filtered and evaporated to give crude 7aÁ
/
/
/
7c
/
/
/
/
1
m.p. 184Á
/
/
/
/
/
/
/
/
/7c, which
1
113Á
/
/
were purified by column chromatography on silica gel

712
A. Balsamo et al. / Il Farmaco 58 (2003) 707Á714
/
using 15:85 AcOEtÁ
/
hexane as the eluent and then
hexane mixture. 7a (40%):
42 8C; H NMR d 2.97 (s, 3H), 3.25Á3.58 (m,
7.81
Hz), 7.00Á
C9H9ClFNO (C, H, N). 14e (40%): H NMR d 3.72 (t,
2H, Jꢀ6.0 Hz), 4.39 (t, 2H, Jꢀ6.0 Hz), 7.05Á7.40 (m,
4H) and 8.10 ppm (s, 1H). Anal. C9H9ClFNO (C, H, N).
/
7.80 (m, 4H) and 8.31 ppm (s, 1H). Anal.
1
crystallized from AcOEtÁ
/
1
m.p. 40Á
/
/
/
/
/
2H), 4.28 (t, 2H, Jꢀ
/
4.8 Hz), 4.80 (br, 1H), 7.20Á
/
(m, 5H) and 8.07 ppm (s, 1H); MS m/z 243 (Mꢁ). Anal.
14f (50%): H NMR d 3.80 (t, 2H, Jꢀ/6.0 Hz), 4.40 (t,
1
1
C10H14N2O3S (C, H, N). 7b (35%): m.p. 74Á
NMR d 3.03 (s, 3H), 3.36Á
Jꢀ5.8 Hz), 5.16 (br, 1H), 7.50 (d, 2H, Jꢀ
/
76 8C; H
2H, Jꢀ6.0 Hz), 6.00 (s, 2H), 6.66Á7.00 (m, 3H) and
/
/
/
3.76 (m, 2H), 4.40 (t, 2H,
8.11 ppm (s, 1H). Anal. C10H10ClNO3 (C, H, N).
/
/8.0 Hz), 7.63
(d, 2H, Jꢀ
/
8.0 Hz) and 8.16 ppm (s, 1H); MS m/z 276
(Mꢁ). Anal. C10H13ClN2O3S (C, H, N). 7c (70%): m.p.
5.1.5. General procedure for the synthesis of the
substituted 3-(benzylideneaminoxy)-1-chloropropane
1
35Á
/
36 8C; H NMR d 2.97 (s, 3H), 3.52 (q, 2H, Jꢀ
/6.4
15a, 15b, 15dÁ
/
15f 4-(benzylideneaminoxy)-1-
Hz), 4.31 (t, 2H, Jꢀ
/
6.4 Hz), 4.80 (br, 1H), 7.22Á
/
7.91
(m, 4H) and 8.48 ppm (s, 1H); MS m/z 276 (Mꢁ). Anal.
C10H13ClN2O3S (C, H, N).
chlorobutane 16a, 16b, 16dÁ
1-chloropentane 17a, 17b, 17f derivatives
/
16f 5-(benzylideneaminoxy)-
A suspension of sodium salt of the appropriate oxime
12, prepared by refluxing the oxime (18 mmol) with
EtONa (18 mmol) in anhydrous EtOH (30 ml), was
evaporated and the residue was dissolved in DMF. The
resulting solution was then added dropwise to a DMF
solution (15 ml) of 1-bromo-3-chloropropane (17.8
mmol) for the preparation of 15, 1-bromo-4-chlorobu-
tane (17.8 mmol) for the preparation of 16, or 1-bromo-
5-chloropentane (17.8 mmol) for the preparation of 17.
The reaction mixture was stirred overnight at room
temperature, then the solvent was removed and the
residue was taken up with CHCl3. The organic phase
was washed with H2O and evaporated to yield a crude
residue, which was subjected to column chromatogra-
5.1.3. Preparation of the 2-(4-
fluorobenzylideneaminoxy)ethyl-methanesulfonamide 7d
A stirred solution of the sodium salt of 4-fluoroben-
zaldoxime (3.23 mmol) in THF (20 ml), prepared by
treatment of 12d with EtONa (3.30 mmol) in anydrous
EtOH, was treated dropwise with a solution of 2-
[(methanesulfonyl)amino]ethylmethanesulfonate (3.23
mmol) in THF (10 ml). The reaction mixture was stirred
at room temperature for 24 h, the solvent was evapo-
rated and the crude residue was purified by chromato-
graphy on silica gel column eluting with 1:1 AcOEtÁ
hexane to yield pure 7d (20%): m.p.77Á78 8C (AcOEtÁ
hexane); H NMR d 2.90 (s, 3H), 3.28Á3.51 (m, 2H),
7.57 (m,
/
/
/
1
/
phy on silica gel eluting with 1:8 AcOEtÁ
to give pure 15a, 15b, 15dÁ15f, 16a, 16b, 16dÁ
17b, and 17f. 15a (57%): 1H NMR d 2.01 (q, 2H, Jꢀ
Hz), 3.76 (t, 2H, Jꢀ6.0 Hz), 4.40 (t, 2H, Jꢀ7.0 Hz),
7.41Á7.96 (m, 5H) and 8.30 ppm (s, 1H); MS m/z 197
(Mꢁ). Anal. C10H12ClNO (C, H, N). 15b (58%): H
NMR d 2.17 (q, 2H, Jꢀ7.0 Hz), 3.65 (t, 2H, Jꢀ6.0
Hz), 4.29 (t, 2H, Jꢀ7.0 Hz), 7.29 (d, 2H, Jꢀ8.8 Hz),
7.48 (d, 2H, Jꢀ8.8 Hz) and 7.99 ppm (s, 1H); MS m/z
232 (Mꢁ). Anal. C10H11Cl2NO (C, H, N). 15d (57%):
1H NMR d 2.18 (q, 2H, Jꢀ
6.4 Hz), 3.67 (t, 2H, Jꢀ6.4
/
hexane mixture
16f, 17a,
7.0
4.30 (t, 2H, Jꢀ
/
5.9 Hz), 4.76 (br, 1H), 7.09Á
/
/
/
4H) and 8.09 ppm (s, 1H); MS m/z 260 (Mꢁ). Anal.
/
C10H13FN2O3S (C, H, N).
/
/
/
1
5.1.4. General procedure for the preparation of the
substituted 2-(benzylideneaminoxy)-1-chloroethane
/
/
derivatives 14aÁ
A suspension of the sodium salt of the appropriate
oxime (12aÁ12f), prepared by refluxing the oxime (32
/
14f
/
/
/
/
mmol) with EtONa (32 mmol) in anhydrous EtOH (85
ml), was added dropwise to a stirred solution of 2-
chloroethyl-1-tolylsulfonate (32 mmol) in anhydrous
EtOH (16 ml). After 12h at room temperature, the
solvent was removed and the residue was taken up with
CHCl3. The organic phase was washed with H2O,
filtered and evaporated. The crude residue was then
subjected to a column chromatography eluting with 1:8
/
/
Hz), 4.29 (t, 2H, Jꢀ6.4 Hz), 7.06 (m, 2H), 7.55 (m, 2H)
/
and 8.30 ppm (s, 1H); MS m/z 215 (Mꢁ). Anal.
1
C10H11ClFNO (C, H, N). 15e (57%): H NMR d 2.21
(q, 2H, Jꢀ
Jꢀ5.4 Hz), 7.07Á
MS m/z 215 (Mꢁ). Anal. C10H11ClFNO (C, H, N). 15f
(55%): 1H NMR d 2.16 (q, 2H, Jꢀ
6.4 Hz), 3.65 (t, 2H,
/
6.4 Hz), 3.75 (t, 2H, Jꢀ
/6.4Hz), 4.40 (t, 2H,
/
/7.41 (m, 4H) and 8.09 ppm (s, 1H);
/
AcOEtÁ
/
hexane mixture to yield pure 14aÁ
/
14f which
was directly used in the subsequent transformation. 14a
Jꢀ
/
6.4 Hz), 4.25 (t, 2H, Jꢀ
/
6.4 Hz), 5.95 (s, 2H), 6.55Á
/
7.45 (m, 3H) and 7.94 ppm (s, 1H); MS m/z 241 (Mꢁ).
1
1
Anal. C11H12ClNO3 (C, H, N). 16a (48%): H NMR d
(40%): H NMR d 3.80 (t, 2H, Jꢀ
Jꢀ6.0 Hz), 7.41Á7.90 (m, 5H) and 8.31 ppm (s, 1H).
Anal. C9H10ClNO (C, H, N). 14b [21] (35%): H NMR
d 3.81 (t, 2H, Jꢀ6.0 Hz), 4.42 (t, 2H, Jꢀ6.0 Hz), 7.40
(d, 2H, Jꢀ10 Hz), 7.70 (d, 2H, Jꢀ10 Hz) and 8.20 ppm
(s, 1H). 14c (15%): H NMR d 3.80 (t, 2H, Jꢀ6.0 Hz),
4.40 (t, 2H, Jꢀ6.0 Hz), 7.20Á8.01 (m, 4H) and 8.61
ppm (s, 1H). Anal. C9H9Cl2NO (C, H, N). 14d (50%):
1H NMR d 3.80 (t, 2H, Jꢀ
6.0 Hz), 4.40 (t, 2H, Jꢀ6.0
/6.0 Hz), 4.40 (t, 2H,
/
/
1.63Á
/
2.21 (m, 4H), 3.68 (t, 2H, Jꢀ6.4 Hz), 4.30 (t, 2H,
/
1
Jꢀ
/
6.4 Hz), 7.36Á8.01 (m, 5H) and 8.30 ppm (s, 1H);
/
/
/
MS m/z 211 (Mꢁ). Anal. C11H14ClNO (C, H, N). 16b
1
/
/
(58%): H NMR d 1.73Á
7.0 Hz), 4.26 (t, 2H, Jꢀ
/
2.23 (m, 4H), 3.73 (t, 2H, Jꢀ
/
1
/
/
7.0 Hz), 7.28 (d, 2H, Jꢀ8.8
/
/
/
Hz), 7.49 (d, 2H, Jꢀ8,8 Hz) and 8.23 ppm (s, 1H); MS
/
m/z 246 (Mꢁ). Anal. C11H13Cl2NO (C, H, N). 16d
1
/
/
(55%): H NMR d 1.74Á
/
2.21 (m, 4H), 3.69 (t, 2H, Jꢀ
/

A. Balsamo et al. / Il Farmaco 58 (2003) 707Á
/
714
713
6.0 Hz), 4.18 (t, 2H, Jꢀ
/
6.0 Hz), 7.05Á
/
7.53 (m, 4H) and
8.04 ppm (s, 1H); MS m/z 229 (Mꢁ). Anal.
C11H13ClFNO (C, H, N). 16e (55%): 1H NMR d
8.09 ppm (s, 1H); MS m/z 245 (Mꢁ). Anal.
C10H12FNO3S (C, H, N). 8f (45%): m.p. 67Á
/
68 8C (i-
PrOH). 1H NMR d 3.0 (s, 3H), 3.40 (t, 2H, Jꢀ
/6.0 Hz),
1.66Á
2H, Jꢀ
/
2.23 (m, 4H), 3.66 (t, 2H, Jꢀ6.0 Hz), 4.30 (t,
/
4.60 (t, 2H, Jꢀ
/
6.0 Hz), 6.0 (s, 2H), 7.66Á
/
7.40 (m, 3H)
and 8.16 ppm (s, 1H); MS m/z 271 (Mꢁ). Anal. C11H13
/
6.0 Hz), 7.13Á7.83 (m, 4H) and 8.20 ppm (s,
/
1H); MS m/z 229 (Mꢁ). Anal. C11H13ClFNO (C, H,
1
NO5S (C, H, N). 9a (30%): m.p. 63Á
/
65 8C (hexane). H
1
N). 16f (60%): H NMR d 1.63Á
/
2.21 (m, 4H), 3.68 (t,
NMR d 1.80Á2.61 (m, 2H), 2.90 (s, 3H), 3.0Á
/
/
3.45 (m,
7.80 (m, 5H) and
2H, Jꢀ
6.99Á
(Mꢁ). Anal. C12H14ClNO3 (C, H, N). 17a (60%): H
NMR d 1.40Á2.26 (m, 6H), 3.66 (t, 2H, Jꢀ7.0 Hz),
/
6.0 Hz), 4.25 (t, 2H, Jꢀ
/
6.0 Hz), 6.13 (s, 2H),
2H), 4.27 (t, 2H, Jꢀ
/
5.8 Hz), 7.75Á
/
8.05 ppm (s, 1H); MS m/z 241 (Mꢁ). Anal. C11H15
/
7.38 (m, 3H) and 8.18 ppm (s, 1H); MS m/z 255
1
1
NO3S (C, H, N). 9b (30%): m.p. 95Á
NMR d 1.95Á2.45 (m, 2H), 2.91 (s, 3H), 2.90Á
2H), 4.29 (t, 2H, Jꢀ 6.4 Hz), 7.23 (d, 2H, Jꢀ
7.47 (d, 2H, Jꢀ8.8 Hz) and 7.99 ppm (s, 1H); MS m/z
275 (Mꢁ). Anal. C11H14ClNO3S (C, H, N). 9d (30%):
m.p. 55Á 2.37 (m, 2H),
56 8C (hexane). 1H NMR d 2.15Á
2.95 (s, 3H), 2.87Á3.26 (m, 2H), 4.25 (t, 2H, Jꢀ6.0 Hz),
7.01Á7.60 (m. 4H) and 8.05 ppm (s, 1H); MS m/z 259
(Mꢁ). Anal. C11H14FNO3S (C, H, N). 9e (25%): m.p.
58Á 2.44 (m, 2H), 2.79
59 8C (hexane). 1H NMR d 2.18Á
(s, 3H), 2.81Á3.66 (m, 2H), 4.28 (t, 2H, Jꢀ6.4 Hz),
/
96 8C (hexane). H
/
/
/
/3.36 (m,
4.36 (t, 2H, Jꢀ
/
7.0 Hz), 7.43Á7.96 (m, 5H) and 8.30
/
/
/8.8 Hz),
ppm (s, 1H); MS m/z 225 (Mꢁ). Anal. C12H16ClNO (C,
/
1
H, N). 17b (40%): H NMR d 1.45Á
(t, 2H, Jꢀ
/2.20 (m, 6H), 3.77
/
6.8 Hz), 4.25 (t, 2H, Jꢀ
/
6.8 Hz), 7.50 (d, 2H,
/
/
Jꢀ
/
8.0 Hz), 7.70 (d, 2H, Jꢀ8.0 Hz) and 8.30 ppm (s,
/
/
/
1H); MS m/z 259 (Mꢁ). Anal. C12H15Cl2NO (C, H, N).
/
1
17f (60%): H NMR d 1.30Á
/2.10 (m, 6H), 3.53 (t, 2H,
Jꢀ
/
5.6 Hz), 4.12 (t, 2H, Jꢀ
/
5.6 Hz), 5.94 (s, 2H), 6.70Á
/
/
/
7.14 (m, 3H) and 7.93 ppm (s, 1H); MS m/z 269 (Mꢁ).
Anal. C13H16ClNO3 (C, H, N).
/
/
7.16Á7.36 (m, 4H) and 8.01 ppm (s, 1H); MS m/z 259
/
(Mꢁ). Anal. C11H14FNO3S (C, H, N). 9f (30%): m.p.
5.1.6. General procedure for the synthesis of the
substituted 1-(methanesulfonyl)-2-(benzylideneaminoxy)
1
110Á
/
111 8C (hexane). H NMR d 2.15Á
/2.34 (m, 2H),
2.91 (s, 3H), 2.97Á
/
3.25 (m, 2H), 4.23 (t, 2H, Jꢀ
/5.6 Hz),
ethane 8aÁ
(benzylideneaminoxy) propane 9a, 9b, 9dÁ
(methanesulfonyl)-4-(benzylideneaminoxy)butane 10a,
10b, 10dÁ10f, and 1-(methanesulfonyl)-5-
(benzylideneaminoxy) pentane 11a, 11b, 11f derivatives
Sodium methanesulfinate (2.23 mmol) and tetrabuty-
lammonium bromide (2.23 mmol) were added to a
stirred solution of the appropriate O-chloroalkyl-oxime
/
8f, 1-(methanesulfonyl)-3-
5.96 (s, 2H), 6.69Á7.22 (m, 3H) and 7.94 ppm (s, 1H);
/
/
9f, 1-
MS m/z 285 (Mꢁ). Anal. C12H15NO5S (C, H, N). 10a
1
(20%): m.p. 39Á
(m, 4H), 2.88 (s, 3H), 2.90Á
Jꢀ5.6 Hz), 7.22Á7.48 (m, 5H) and 8.03 ppm (s, 1H);
Anal. C12H17NO3S (C, H, N). 10b (30%): m.p. 84Á
/
40 8C (i-Pr2O). H NMR d 1.70Á
/2.25
/
/
3.31 (m, 2H), 4.19 (t, 2H,
/
/
/
85 8C
1
(i-Pr2O). H NMR d 1.65Á
2.85Á
Jꢀ9.6 Hz), 7.49 (d, 2H, Jꢀ
1H); Anal. C12H16Cl NO3S (C, H, N). 10d (30%): m.p.
/2.30 (m, 4H), 2.88 (s, 3H),
/
3.25 (m, 2H), 4.18 (t, 2H, Jꢀ
/5.6 Hz), 7.28 (d, 2H,
ether 14Á17 (2.15 mmol) in DMF (10 ml). The resulting
/
/
/9.6 Hz) and 7.98 ppm (s,
solution was stirred at 85 8C for 5 days and then cooled,
diluted with water and extracted with CHCl3. The
organic layers were washed several times with water,
filtered and evaporated to yield a crude residue which
was purified crystallized from the proper solvent to give
1
73Á
(s, 3H), 3.04Á
7.02Á7.59 (m, 4H) and 8.04 ppm (s, 1H); Ana-
l.C12H16FNO3S (C, H, N). 10e (25%): m.p. 40Á
/
74 8C (i-Pr2O). H NMR d 1.88Á
/
2.15 (m, 4H), 2.90
/
3.12 (m, 2H), 4.19 (t, 2H, Jꢀ
/5.6 Hz),
/
64 8C (i-PrOH); 1H NMR
5.9 Hz), 4.60 (t, 2H, Jꢀ
/
41 8C
pure 8Á
/
11. 8a (40%): m.p. 63Á
/
1
(i-Pr2O). H NMR d 1.70Á
2.91Á
(m, 4H) and 8.0 ppm (s, 1H); Anal. C12H16 FNO3S (C,
H, N). 10f (20%): m.p. 110Á
111 8C (i-Pr2O). 1H NMR d
1.65Á2.30 (m, 4H), 2.88 (s, 3H), 2.90Á3.21 (m, 2H), 4.15
(t, 2H, Jꢀ6.4 Hz), 5.95 (s, 2H), 6.50Á7.35 (m, 3H) and
7.93 ppm (s, 1H); Anal. C13H17 NO5S (C, H, N). 11a
/2.25 (m, 4H), 2.89 (s, 3H),
d 3.0 (s, 3H), 3.50 (t, 2H, Jꢀ
/
/
/
3.20 (m, 2H), 4.20 (t, 2H, Jꢀ
/
5.6 Hz), 6.90Á7.40
/
5.9 Hz), 7.3Á7.9 (m, 5H) and 8.20 ppm (s, 1H); MS m/z
/
227 (Mꢁ). Anal. C10H13NO3S (C, H, N). 8b (55%): m.p.
1
/
86Á
Jꢀ
Hz), 7.70 (d, 2H, Jꢀ
m/z 261 (Mꢁ). Anal. C10H12ClNO3S (C, H, N). 8c
(45%): m.p. 93Á
94 8C (i-PrOH). 1H NMR d 3.0 (s, 3H),
3.5 (t, 2H, Jꢀ6.0 Hz), 4.70 (t, 2H, Jꢀ6.0 Hz), 7.20Á
8.10 (m, 4H) and 8.70 ppm (s, 1H); MS m/z 261 (Mꢁ).
Anal. C10H12ClNO3S (C, H, N). 8d (60%): m.p. 47Á
/
87 8C (i-PrOH); H NMR d 3.0 (s, 3H), 3.5 (t, 2H,
/
/
/
5.8 Hz), 4.70 (t, 2H, Jꢀ
/
5.8 Hz), 7.50 (d, 2H, Jꢀ8.8
/
/
/
/8.8 Hz) and 8.20 ppm (s, 1H); MS
1
(20%): m.p. 44Á
(m, 6H), 2.87 (s, 3H), 3.02Á
Jꢀ5.6 Hz), 7.22Á7.51 (m, 5H) and 8.02 ppm (s, 1H);
Anal. C13H19NO3S (C, H, N). 11b (20%): m.p. 72Á
/
45 8C (hexane). H NMR d 1.40Á
/2.20
/
/
3.31 (m, 2H), 4.16 (t, 2H,
/
/
/
/
/
/
73 8C
/
1
1
(hexane). H NMR d 1.40Á
2.90Á
Jꢀ9.6 Hz), 7.48 (d, 2H, Jꢀ
1H); Anal. C13H18ClNO3S (C, H, N). 11f (20%): m.p.
78Á 2.10 (m, 6H), 2.87
79 8C (hexane). 1H NMR d 1.35Á
(s, 3H), 2.90Á3.17 (m, 2H), 4.12 (t, 2H, Jꢀ5.2 Hz), 5.95
/2.20 (m, 6H), 2.87 (s, 3H),
48 8C (i-PrOH). H NMR d 3.0 (s, 3H), 3.50 (t, 2H,
Jꢀ6.0 Hz), 4.60 (t, 2H, Jꢀ6.0 Hz), 7.00Á7.90 (m, 4H)
and 8.20 ppm (s, 1H); MS m/z 245 (Mꢁ). Anal.
C10H12FNO3S (C, H, N). 8e (45%): m.p. 46Á47 8C (i-
PrOH). H NMR d 2.98 (s, 3H), 3.46 (t, 2H, Jꢀ5.6
Hz), 4.60 (t, 2H, Jꢀ5.6 Hz), 7.01Á7.39 (m, 4H) and
/
3.21 (m, 2H), 4.16 (t, 2H, Jꢀ
/
6.4 Hz), 7.28 (d, 2H,
/
/
/
/
/9.6 Hz) and 7.98 ppm (s,
/
1
/
/
/
/
/
/
/

714
A. Balsamo et al. / Il Farmaco 58 (2003) 707Á714
/
(s, 2H), 6.79Á
/
7.20 (m, 3H) and 7.93 ppm (s, 1H); Anal.
References
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Compounds 7Á11 were tested in intact cell assays to
/
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/
/
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/
˚
derivative convergence at 0.05 kJ/A mol in which no
/
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kind of restraint was applied. The calculations were
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dependent electrostatic treatment and dielectric constant
4.0.
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/