A sulfonating ionic liquid for one-pot pseudo four-component synthesis of novel 3-chlorosulfonyl-δ-sultones: A novel class of fluorescent compounds

Article abstract of DOI:10.1016/j.tet.2018.06.012

An active imidazolium-based ionic liquid mixture was developed for efficient synthesis of some novel 4,6-diaryl-3-(chlorosulfonyl)-1,2-oxathiine-2,2-dioxides (chlorosulfonyl-δ-sultones) from simple acetophenones at room temperature. The ionic liquid mixtu

Full text of DOI:10.1016/j.tet.2018.06.012

Tetrahedron xxx (2018) 1e6
Contents lists available at ScienceDirect
Tetrahedron
journal homepage: www.elsevier.com/locate/tet
A sulfonating ionic liquid for one-pot pseudo four-component
synthesis of novel 3-chlorosulfonyl-
d-sultones: A novel class of
fluorescent compounds
*
Saeedeh Toorchi Roudsari, Kurosh Rad-Moghadam
Chemistry Department, University of Guilan, P.O. Box 41335-1914, Rasht, Iran
a r t i c l e i n f o
a b s t r a c t
Article history:
Received 7 April 2018
Received in revised form
An active imidazolium-based ionic liquid mixture was developed for efficient synthesis of some novel
4,6-diaryl-3-(chlorosulfonyl)-1,2-oxathiine-2,2-dioxides (chlorosulfonyl-d-sultones) from simple aceto-
phenones at room temperature. The ionic liquid mixture acts as a catalyst to condense two molecules of
an acetophenone derivative and as a mild sulfonating agent to convert the resulting condensate into 4,6-
diaryl-1,2-oxathiine-2,2-dioxides, and finally as a chlorosulfonating reagent to deliver the desired fully
30 May 2018
Accepted 5 June 2018
Available online xxx
unsaturated chlorosulfonyl-d-sultones in onepot. The products were separated easily from the reaction
mixture and showed valuable fluorescence properties. The structures of these products are in good
Keywords:
Pseudo four-component reaction
Chlorosulfonylation
agreement with their 1H NMR, C NMR, and mass spectral data. All rights reserved.
13
©
2018 Elsevier Ltd. All rights reserved.
d-Sultones
Ionic liquid
Fluorescent compounds
1. Introduction
there have been significant drawbacks in using hazardous reagents
by these routes leading to highly toxic and harmful gaseous
7
Sulfonyl chloride-substituted compounds constitute a versatile
class of reactive molecules with diverse and important applications
in pharmaceutical, agricultural, and dyeing industries. They have
also been widely applied as key intermediates for synthesis of many
organosulfur compounds such as sulfones, sulfonates, sulfinic acids,
byproducts. Therefore, it is more favorable to employ relatively
mild and efficient ionic liquid-based reagents for running the re-
actions in a straightforward manner to achieve better selectivity
and yields of arylsulfonyl chlorides. Ionic liquids (ILs) have been
widely applied in many organic reactions, due to their notable and
impressive characteristics, including wide liquid temperature
range, tunable polarity, consisting of reactive non-coordinated ions,
and having no measurable vapour pressure that make them
greener alternatives to the conventional organic solvents. Thanks
to these outstanding characters, ionic liquids have shown versatile
capabilities in promoting many reactions, altering the outcome of
reactions, and improving the selectivity aspects of chemical pro-
1
and sulfonamides. Attention to sulfonyl chlorides even received a
renaissance after the recent discovery of metal-catalyzed addition
2
of these compounds onto alkynes. Consequently, researchers and
8
,9
industries are in need of improved methods for synthesis of these
useful building blocks. Current approaches to synthesis of arylsul-
fonyl chlorides are classified into three broad routes. These involve
chlorination or oxidative chlorination of relevant sulfur com-
3
4
10
pounds, conversion of aryldiazonium salts derived from anilines,
cesses. These efficiencies of ionic liquids strictly depend on the
nature of their ionic constituents and can be enhanced by func-
tionalization of their bulky cations with proper acidic or basic
5
conversion of arylboronic acids, and direct chlorosulfonation of
aromatic compounds with chlorosulfonic acid. Although the first
6
11,12
three routes result in perfect regiocontrolled chlorosulfonated
products, they suffer from using either explosive diazonium in-
termediates or remarkably harsh oxidation conditions and are only
applicable to properly substituted aromatic compounds. Moreover,
groups.
Synthesis of the first Brønsted acid functionalized ionic
13
liquid goes back to the work of Davis and coworkers in 2002. Since
then, several types of Brønsted acidic ILs have been reported, which
show great potentials for replacing the conventional acid catalysts
in many chemical processes. Although ionic liquids were initially
known as friendly solvents and clean catalysts, they are now going
to find additional roles as reagents in a number of reactions as
14
*
Corresponding author.
E-mail address: radmm@guilan.ac.ir (K. Rad-Moghadam).
https://doi.org/10.1016/j.tet.2018.06.012
040-4020/© 2018 Elsevier Ltd. All rights reserved.
0
Please cite this article in press as: Toorchi Roudsari S, Rad-Moghadam K, A sulfonating ionic liquid for one-pot pseudo four-component synthesis
of novel 3-chlorosulfonyl- -sultones: A novel class of fluorescent compounds, Tetrahedron (2018), https://doi.org/10.1016/j.tet.2018.06.012
d

2
S. Toorchi Roudsari, K. Rad-Moghadam / Tetrahedron xxx (2018) 1e6
Table 1
Exploring the efficiency of the ionic liquid [MSIm]OTf$HCl contaminated with different additives in the pseudo-four-component reaction with acetophenone derivatives.
Enta
Ionic liquid
Additive
Solvent
Temp. ( C)
ꢁ
Time (h)
Yield (%)b of 3c
c
1
2
3
4
5
6
7
8
[MSIm]OTf$HCl
[MSIm]OTf$HCl
[MSIm]OTf$HCl
[MSIm]OTf$HCl
[MSIm]OTf$HCl
[MSIm]OTf$HCl
[MSIm]OTf$HCl
[MSIm]OTf$HCl
ClSO
ClSO
3
H
H
e
25
25
25
35
25
25
25
25
12
12
4
NP
NP
c
3
CH
e
2
Cl
2
d
(CF
(CF
3
CO)
CO)
2
O
O
59
34
NP
NP
NP
NP
3
2
e
4
CF
CF
(CH
CH
3
SO
3
H
e
12
12
12
12
3
COOH
CO)
e
3
2
O
e
e
3
COOH
e
a
Reaction conditions: 4-chloroacetophenone 1c (1 mmol), IL (1.6 mmol), and the additive (2 mmol in each case).
Yields of the isolated product 3c, in other cases (NP) the yield of 3c is negligible and only 2c can be resolved.
Carbonization occurs.
The reaction proceeds slightly after this time.
Glacial.
b
c
d
e
well.15e18 Recently, we demonstrated that 3-methyl-1-
[MSIm]OTf$HCl and 4-chloroacetophenone was initially explored
and the results were summarized in Table 1. As this table shows,
addition of trifluoroacetic anhydride (TFAA) to the reaction mixture
results in formation of the desired product 3-chlorosulfonyl-4,6-
di(4-chlorophenyl)-1,2-oxathiine-2,2-dioxide 3c in moderate yield
(entry 3). This was really a promising observation, representing the
ionic liquid as a potent chlorosulfonating agent. It is activated by
TFAA to yield 3c from the intermediate product 4,6-di(4-
chlorophenyl)-1,2-oxathiine-2,2-dioxide 2c, which in turn is pro-
duced from the reaction of the IL and 4-chloroacetophenone.
Owing to formation of byproducts, the yield of 3c is diminished by
increasing the reaction temperature (entry 4). It is worthy to note
that application of the ionic liquid [MSIm]OTf$HCl doped with
sulfonylimidazolium chloride doped with an equimolar amount
of triflic acid, [MSIm]OTf$HCl, can act as a catalyst and sulfonating
ionic liquid in reaction with acetophenone derivatives to give 4,6-
19
diaryl-1,2-oxathiine-2,2-dioxides (
d
-sultones). Here, we demon-
strate the fluorescence emission of these fully unsaturated
d-sul-
tones and show how their fluorogenic character is enhanced by
chlorosulfonation on the sultone ring. In this regard, we explain
here, for the first time, a one-pot procedure for synthesis of 4,6-
diaryl-3-(chlorosulfonyl)-1,2-oxathiine-2,2-dioxides (4,6-diaryl-3-
chlorosulfonyl-d-sultones) from acetophenone derivatives by us-
ing a new ionic liquid mixture. Sultones are valuable materials and
2
0
many routes to their synthesis have been developed.
3
ClSO H leads to carbonization of the reaction mixture and forma-
tion of multiple byproducts (entries 1,2). Other additives shown in
Table 1 proved to be inefficient in activating the ionic liquid toward
chlorosulfonation of the intermediate product 2c (entries 5e8).
After determining TFAA as the superior additive, we proceeded
to optimize the reaction condition further by changing the anionic
constituent of the ionic liquid. Table 2 indicates that the conjugate
anions of strong acids endow similar reactivity to the ionic liquid as
triflate do (entries 1e3). However, the best result was obtained
2
. Results and discussion
However, [MSIm]OTf$HCl plays as a condensing catalyst and
sulfonating ionic liquid in reaction with acetophenone derivatives
to give 4,6-diaryl-1,2-oxathiine-2,2-dioxides, it is not reactive
enough to chlorosulfonate the products. Therefore, in order to
impart such an ability to the ionic liquid, we aimed at activating it
preferably by changing at least one of its anionic constituents or by
adding an activating agent to the reaction mixture. For this purpose,
the effect of some selected additives on the trial reaction between
ꢀ
ꢀ
when ClSO
3
was used instead of OTf in fabrication of the ionic
$HCl, over the other ionic
liquid. The supremacy of [MSIm]ClSO
3
Table 2
Finding the optimal ionic liquid mixture for synthesis of 4,6-di(4-chlorophenyl)-3-(chlorosulfonyl)-1,2-oxathiine-2,2-dioxide 3c.
Enta
Ionic liquid
[MSIm]HSO
Additive
Solventc
Temp. ( C)
ꢁ
Time (h)
Yield (%)d
1
2
3
4
5
6
7
8
4
$HCl
$HCl
$HCl
(CF
3
(CF
3
(CF
3
(CF
3
(CF
3
(CF
3
(CF
3
e
CO)
CO)
CO)
CO)
CO)
CO)
CO)
2
2
2
2
2
2
2
O
O
O
O
O
O
O
e
e
e
e
25
25
25
25
25
r.t
r.t
r.t
0
4
3.5
4
12
12
12
12
12
12
64
96
68
NP
21
21
23
NP
Trace
[MSIm]ClSO
3
[MSIm]ClO
[MSIm]Cl
4
[MSIm]ClSO
[MSIm]ClSO
[MSIm]ClSO
[MSIm]ClSO
e
3
$HCl
3
$HCl
3
$HCl
3
$HCl
CH
2
Cl
2
THF
Toluene
e
b
9
3
ClSO H
Toluene
a
Reaction conditions (for entries 1e8): 4-chloroacetophenone (1 mmol), IL (1.6 mmol), and trifluoroacetic anhydride (2 mmol).
b
c
4
1
,6-di(4-chlorophenyl)-1,2-oxathiine-2,2-dioxide 2c (1.09 mmol) and chlorosulfonic acid (3.5 mmol).
mL in each case.
d
Isolated yields of 3c.
Please cite this article in press as: Toorchi Roudsari S, Rad-Moghadam K, A sulfonating ionic liquid for one-pot pseudo four-component synthesis
of novel 3-chlorosulfonyl- -sultones: A novel class of fluorescent compounds, Tetrahedron (2018), https://doi.org/10.1016/j.tet.2018.06.012
d

S. Toorchi Roudsari, K. Rad-Moghadam / Tetrahedron xxx (2018) 1e6
3
Table 3
liquids of Table 2, can be partially attributed to regeneration of the
Optimizing the molar ratio of [MSIm]ClSO
3
$HCl/TFAA in the model synthesis of 3c.
ꢀ
MSIm cation by ClSO
3
after consumption in the synthesis of 3. To
Entry
IL/TFAA (mmol)a
Time (h)
Yield (%)b
explore if ClSO
ꢀ
is so reactive in the ionic liquid medium to directly
chlorosulfonate the intermediate 2c, the model reaction was per-
formed in sole [MSIm]ClSO $HCl, however, the product 3c was not
formed sensibly in this trial reaction (entry 8). Further experiments
revealed that diluting the mixture of [MSIm]ClSO $HCl and TFAA
with organic solvents markedly diminishes the yield of 3c (entries
e7). This observation is implying the necessity of the ionic me-
dium for success of the synthesis. Although, chlorosulfonation of
organic substrates are normally carried out in toluene by using
3
ClSO H, application of this method to synthesis of 3c from 2c leads
1
2
3
4
5
6
2:1
3.5
3.5
3.5
3.5
3.5
3.5
53
96
96
78
21
trace
1.6:2
1.6:2.5
1.6:1
1:2
3
3
1:1
5
a
Applied to 4-chloroacetophenone (1 mmol).
Isolated yields of 3c, the experiments were repeated three times and the stan-
b
dard deviation was calculated to be around ±2%.
to decomposition of the substrate at ambient temperature and
ꢁ
delivers only a trace amount of the product 3c at 0 C even after
1
2 h (entry 9). The inefficiency of this method is due to instability of
the -sultone 2 in chlorosulfonic acid.
Based on these preliminary evaluations, [MSIm]ClSO
d
3
$HCl and
TFAA were chosen as the best IL and additive for the present inves-
tigation. It is noticeable that the yield and time of the trial synthesis
are significantly dependent on the quantities of these reagents. To
find out the optimum amounts of these reagents, a range of their
molar ratios was tested in the synthesis of 3c. According to the re-
sults summarized in Table 3, better yields were obtained by using 1/
1.6/2 M ratio of 4-chloroacetophenone, the IL, and TFAA. Higher
amounts of the IL and TFAA were deemed undesirable.
However we have not proved the mechanism of the present
synthesis experimentally, a reasonable sequence of reactions
leading to production of the unsaturated
d
-sultone 2 was suggested
19
in our previous paper (Scheme 1).
Likely, the ionic liquid [MSIm]ClSO
3
$HCl exists in the form of
three equilibrating species I-III. Based on being composed of these
interconvertible species, the ionic liquid can act as a sulfonating
19
agent in reaction with acetophenones to give the d-sultones 2.
Activation of the ionic liquid by TFAA is conceivable in term of
formation of the anhydride 4b, which may be in an equilibrium
with the dicationic species 4a. The Friedel-Crafts reaction of 4 with
the initially formed
(Scheme 1).
In the next phase of this study, we set out to explore the sub-
d-sultone 2 results in formation of the product
3
strate scope of the herein presented synthetic method. For this
purpose, different acetophenone derivatives were examined under
the conditions set forth above for the trial synthesis. The results
point out that the synthetic method is very sensitive to the nature
and position of the substituents present on the aromatic ring of
acetophenones. In our hand, only acetophenone and 4-
haloacetophenones were converted to the corresponding prod-
ucts 3a-3e through reaction with the IL mixture (Table 4). Other
Scheme 1. A mechanism proposed for the synthesis of the products 3.
Table 4
3
Preparation of 4,6-diaryl-3-(chlorosulfonyl)-1,2-oxathiine-2,2-dioxides 3a-3e using the optimal mixture of [MSIm]ClSO $HCl and TFAA.
Entry
Ara
Time (h)
Yieldb (%)
3
3
3
3
3
a
b
c
d
e
C
4-F C
4-Cl C
6 4
4-Br C H
6
H
5
5
4
3.5
3.5
4
92
95
96
91
78
.
6
H
4
.
6
H
4
.
.
6 4
4-I C H
a
Reaction conditions: An acetophenone derivative 1 (1 mmol), [MSIm]ClSO
Isolated yields, the experiments were repeated three times and the standard deviation was calculated to be around ±2%.
3
$HCl (1.6 mmol) and trifluoroacetic anhydride (2 mmol) at room temperature.
b
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of novel 3-chlorosulfonyl- -sultones: A novel class of fluorescent compounds, Tetrahedron (2018), https://doi.org/10.1016/j.tet.2018.06.012
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4
S. Toorchi Roudsari, K. Rad-Moghadam / Tetrahedron xxx (2018) 1e6
contribution of the resonance form 3 ʹʹ. That is, at least in the elec-
tronic excited state, the chlorine atom is more readily able to
interact with the phenyl ring than is the fluorine atom. Notably, this
ability is slightly diminished for the heavier halogens and so the
resonance interaction of halogens in the products 3b-3e can be
ordered as Cl > Br > I > F. An explanation is that the resonance
interaction becomes less favorable for the heavier halogens, since
the size of the interacting lone-pair P orbitals and the length of
bond with the aromatic ring is increased for the heavier halogens.
On the other hand, the intensity of this band reveals an explicit
dependence on size of the group at para position of the aryl rings
and is ordered as I > Br > Cl > F > H.
Another interesting trend is noticed in the fluorescence spectra
of the products 3b-3e at wavelengths between 465 nm and 580 nm
Fig. 1. The absorption spectra of 4,6-diaryl-3-(chlorosulfonyl)-1,2-oxathiine-2,2-
dioxide 3a-3e in dichloromethane solutions (5 ꢂ 10 ꢀ4 M).
(Fig. 3). At this range and vast near wavelengths around, no emis-
sion peak is seen for the 2,4-diphenyl derivative 3a. Like the ab-
sorption spectra, the position and intensity of the fluorescence
spectra of 3b-3e show significant dependence on the aromatic
halogen. For the compounds 3b and 3c, the intensity of emission
seems to be a measure of absorption which is affected by the
halogen substituent and appears as Cl > F. However, despite of
enhanced absorptions in the cases of compounds 3d and 3e, the
intensity of fluorescence largely diminishes by the so-called inter-
nal heavy atom effect. In general, the heavy atoms present as
substituents in aromatic molecules cause to fluorescence quench-
ing because of the increased probability of intersystem crossing
Fig. 2. Two representative resonance forms of the molecule.
acetophenone derivatives either gave only the intermediate prod-
ucts 2 or like 2esubstituted acetophenones were not essentially
able to form d-sultone ring.
(radiationless transition). In fact, this effect is favoured by spin-
orbit coupling and its efficiency directly depends on the atomic
Because of possessing two sulfonyl groups properly conjugated
with the two aromatic substituents, these products are expected to
feature energetically favorable push-pull resonance structures. As a
fact, these products have shown an electronic absorption band at
visible to near visible wavelengths (Fig. 1). This band can be
imagined to owe its existence to the extended dipolar resonance
form 3ʹ and reasonably shift to higher wavelengths as the reso-
nance form becomes more energetically feasible (Fig. 2). Therefore,
the position of this band provides a measure of the mesomeric
interaction within the molecule and is sensibly affected by the size
and electronegativity of the halogen substituent. Fig. 1 displays that
the products 3a and 3b have approximately similar bands peaking
at 313 nm. The similarity of the absorption bands for 3a and 3b was
also previously noted for the B-bands of benzene and fluo-
robenzene,21 implying that the extent with which the fluorine atom
takes part in the mesomeric interaction is largely limited due to its
small size and high electronegativity. However, replacement of F
with Cl results in displacement of the band to longer wavelengths.
This bathochromic shift (~50 nm) can be attributed to the increased
22
number of the substituent atom by a power of 4. Therefore, the
intensity of fluorescence for these products is a compromise be-
tween the probability of absorption and intersystem crossing and
increase by increasing the atomic number of the halogen substit-
uent. As a result of the opposing effects of these two factors, the 2,4-
di(4-iodophenyl) derivative 3e has the minimum fluorescence in-
tensity and the 2,4-di(4-chlorophenyl) derivative 3c holds the
highest fluorescence intensity within these products. Please note
that the spectrum of 3c was recorded with a slit narrower than the
other derivatives, otherwise it would be over range. Fig. 3 also
displays that the fluorescence emission shifts to longer wave-
lengths as the halogen substituent becomes heavier.
In order to explore the effect of the chlorosulfonyl group on both
the position and wavelength of the fluorescence band, we have
compared the fluorescence spectrum of the compounds 3c and 2c
in Fig. 4. As this figure shows, the product 3c, with the chlor-
osulfonyl substituent, fluoresces with much more intensity than its
parent molecule 2c. This figure also displays that the fluorescence
Fig. 3. The fluorescence spectra of 4,6-diaryl-3-(chlorosulfonyl)-1,2-oxathiine-2,2-
dioxide 3b-3e solutions (5 ꢂ 10 M) in dichloromethane.
Fig. 4. Fluorescence intensities of 3c and 2c in dichloromethane solutions (5 ꢂ 10
ꢀ
4
ꢀ4
M). The slit width for both excitation and emission was set to 2.5 nm.
Please cite this article in press as: Toorchi Roudsari S, Rad-Moghadam K, A sulfonating ionic liquid for one-pot pseudo four-component synthesis
of novel 3-chlorosulfonyl- -sultones: A novel class of fluorescent compounds, Tetrahedron (2018), https://doi.org/10.1016/j.tet.2018.06.012
d

S. Toorchi Roudsari, K. Rad-Moghadam / Tetrahedron xxx (2018) 1e6
5
ꢁ
spectra are broad and structureless for both the compounds and
that the maximum emission of 3c only slightly (~3 nm) shifts to a
longer wavelength by presence of the chlorosulfonyl substituent.
Presumably, for steric reasons the plane of this group orients
perpendicular to the plane of the sultone ring, hence do not involve
water (2 ꢂ 5 mL). The solid residue was dried at 30 C in vacuo,
ꢁ
washed with n-hexane (5 mL), and again dried at 30 C in vacuo to
give the product 3c as yellow powder (0.434 g, 96%).
4.2.1. 4,6-Diphenyl-3-(chlorosulfonyl)-1,2-oxathiine-2,2-dioxide
considerably in conjugation with the
. Conclusions
,6-Diaryl-3-(chlorosulfonyl)-1,2-oxathiine-2,2-dioxides,
novel fluorescent compounds, were synthesized efficiently from
simple acetophenone derivatives in one pot. The key reagent of this
straight but complex transformation is an ionic liquid mixture
which acts as both catalyst and sulfonating agent to run a harmony
of CeC, CeS, and SeO bonds formations leading to synthesis of the
products. The chlorosulfonyl substituent of these products were
p
-system of the molecule.
(3a)
ꢁ
Yield 92%. Mp ¼ 146 C. IR (KBr):
nmax 3233 and 3069 (CeH Str),
3
2922, 1623 (C]C), 1374 and 1182 (S]O Str), 794, 756 (SeO),
ꢀ
1 1
697 cm . H NMR (400.22 MHz, CDCl
3 H
): d 7.87 (2H, d, J 7.8 Hz, 4-Ar
4
as
2ʹ,6ʹ-H), 7.66 (1H, t, J 7.4 Hz, 4-Ar 4ʹ-H), 7.62e7.55 (5H, m), 7.49 (2H,
13
d, J 7.2 Hz, 6-Ar 2ʺ,6ʺ-H), 6.65 (1H, s, 5-H) ppm. C NMR
(100.65 MHz, CDCl ): 159.9 and 157.4 (C-1ʹ and C-1ʺ), 134.1, 133.8
(CH), 130.9 (CH), 129.5 (2CH), 129.0, 128.9 (2CH), 127.3 (2CH), 127.2,
3
d
C
þ
37
127.1 (2CH), 106.8 (C-5). MS (70 eV): m/z (%) ¼ 384 (M , Cl, 10),
þ
þ
35
þ
37
þ
, 35Cl, 10),
, 20), 191 (M
382 (M , Cl, 23), 320 (M ꢀ SO
2
,
Cl, 3), 318 (M ꢀ SO
2
þ
þ
284 (M -SO
2
Cl, 13), 235 (20), 220 (M -SO
2
Cl -SO
2
shown to enhance the fluorescence emission of the parent
tone skeleton and is anticipated to enable the products to be
d
-sul-
-CClO
5
S
2
, 100), 165 (14), 105 (58), 77(49). Anal. Calculated for
): C 50.20; H 2.90%. Found: C 50.26; H 2.87%.
(C16H11ClO S
5 2
applied as new fluorescent probes.
4
.2.2. 4,6-Di(4-fluorophenyl)-3-(chlorosulfonyl)-1,2-oxathiine-2,2-
dioxide (3b)
Yield 95%. Mp ¼ 150 C. IR (KBr):
C), 1382 and 1185 (S]O Str), 958, 829 (SeO), 645 cm . H NMR
4
. Experimental section
ꢁ
n
max 3119 (CeH Str), 1613 (C]
ꢀ
1 1
All the chemicals required for the reactions were purchased
from Sigma-Aldrich and Merck companies and used without
3
4
(400.22 MHz, CDCl
Ar 2ʹ,6ʹ-H), 7.48 (2H, dd, JHH 9.2 Hz and JFH 5.2 Hz, 6-Ar 2ʺ,6ʺ-H),
(4H, t, JHHz JFH 8.5 Hz, 4-Ar 3ʹ,5ʹ-H and 6-Ar 3ʺ,5ʺ-H), 6.54 (1H, s,
5-H) ppm. C NMR (100.65 MHz, CDCl
and 163.9 (d, JCF 187 Hz) (C-4ʹ and C-4ʺ), 159.1 and 156.2 (C-1ʹ and
C-1ʺ), 131.4, 129.8 (d, JCF 5 Hz, 2CH), 129.7 (d, JCF 5 Hz, 2CH), 125.3,
117.1 (d, JCF 22 Hz, 2CH), 116.6, 116.3 (d, JCF 22 Hz, 2CH), 106.4 (C-
3 H
): d 7.88 (2H, dd JHH 8.8 Hz and JFH 4.8 Hz, 4-
3
4
further purification. Melting points were determined using a B u chi
1
3
3
B-545 apparatus and are uncorrected. The H NMR (400 MHz)
13
1
spectra were recorded on a Bruker DRX-400 spectrometer using
CDCl as solvent and the chemical shifts were measured in ppm
3
3
):
C
d 166.5 (d, JCF 191 Hz)
1
3
3
with respect to the chemical shift of this deuterated solvent. FT-IR
spectra of the products were recorded as KBr pellets on a Shi-
madzu FT-IR 8300 spectrometer. The mass spectral data were ob-
tained with an Agilent Technology 5973 Network. The UV
absorption spectra were recorded in dichloromethane using a
Shimadzu UVeVis 1800 double beam spectrophotometer. Fluo-
2
2
þ
35
þ
35
5). MS (70 eV): m/z (%) ¼ 418 (M , Cl, 14), 354 (M ꢀ SO
2
,
Cl, 10),
, 19), 227 (M -CClS
ClSO , 10), 201 (11), 123 (73), 95 (47). Anal.
2 5 2
ClF O S ): C 45.88; H 2.17%. Found: C 45.93; H
þ
þ
þ
320 (M -SO
2
Cl, 11), 256 (M -SO
2
Cl -SO
2
2 5
O ,
þ
100), 208 (M -C
Calculated for (C16
2.14%.
6
H
4
3
H
9
ꢁ
rescence emission spectra were recorded at 25 C between
l
em ¼ 465 nm and 580 nm on a Varian Cary Eclipse spectrofluo-
rometer with excitation at
ex ¼ 440 nm. Both the excitation and
emission slit widths were set to 2.5 nm or 4 nm.
l
4.2.3. 4,6-Di(4-chlorophenyl)-3-(chlorosulfonyl)-1,2-oxathiine-2,2-
dioxide (3c)
ꢁ
Yield 96%. Mp ¼ 178 C. IR (KBr):
nmax 3112 (CeH Str), 2924, 1609
ꢀ1 1
4.1. Synthesis of [MSIm]ClSO
3
·HCl
(C]C), 1489, 1389 and 1185 (S]O), 1093, 1014 (SeO), 824 cm . H
NMR (400.2 MHz, CDCl ): 7.80 (2H, d, J 8.4 Hz, 4-Ar 2ʹ,6ʹ-H), 7.55
(4H, d, J 8.4 Hz, 4-Ar 3ʹ,5ʹ-H and 6-Ar 3ʺ,5ʺ-H), 7.43 (2H, d, J 8.4 Hz,
3
d
H
This ionic liquid was prepared according to our previously re-
ported protocol.19 Thus, in a typical procedure, 1-methylimidazole
0.821 g, 10 mmol) and dry dichloromethane (15 mL) were mixed
13
6-Ar 2ʺ,6ʺ-H), 6.57 (1H, s, 5-H) ppm. C NMR (100.65 MHz, CDCl
159.1 and 155.7 (C-1ʹ and C-1ʺ), 140.7, 137.5, 132.2, 130.0 (2CH),
129.7, 129.3 (2CH), 128.8 (2CH), 128.3 (2CH), 127.4, 106.6 (C-5). MS
3
):
(
d
C
in the reaction vessel by stirring. The vessel was sealed by a rubber
septum and immersed in an ice-cold bath. In this time, chlor-
osulfonic acid (2.389 g, 20.5 mmol) was added dropwise by a sy-
ringe. Stirring was continued at room temperature for 1 h. Finally,
the solvent was evaporated in vacuo to obtain the ionic liquid as a
viscous pale yellow oil.
þ
37
37
35
þ
37
35
35
(70 eV): m/z (%) ¼ 454 (M , Cl Cl Cl, 5), 452 (M , Cl Cl Cl,
þ
þ
35 35 35
þ
37 37 35
16), 450 (M , Cl Cl Cl, 15), 390 (M ꢀ SO
2
,
Cl Cl Cl, 4), 389
37
35
35
þ
35
35
35
(2), 388 (M ꢀ SO
2
,
Cl Cl Cl, 11), 386 (M ꢀ SO
2
,
Cl Cl Cl,
þ
Cl, Cl37Cl, 2), 354 (M -SO
þ
2 2
11), 356 (M -SO Cl, Cl Cl, 12), 352
37
37 35
þ
35 35
þ
37
Cl37Cl, 4), 290 (M
þ
(M -SO
2
Cl, Cl Cl, 16), 292 (M -SO
2
Cl -SO
2
,
þ
35 35
-
SO
2
Cl -SO
2
, 37Cl35Cl, 21), 289 (7), 288 (M -SO
2
Cl -SO
2
,
Cl Cl 33),
þ
37 35
þ
35 35
4.2. Typical procedure for synthesis of 4,6-di(4-chlorophenyl)-3-
261 (M -CClS
2
O
5
,
Cl Cl, 68), 259 (M -CClS
2
O
5
,
Cl Cl, 100),
, 35Cl, 15), 189
): C 42.54;
þ
37
þ
(
chlorosulfonyl)-1,2-oxathiine-2,2-dioxide (3c)
226 (M -C
6
H
4
Cl
2
SO
3
,
Cl, 27), 224 (M -C
6
H
4
Cl
2
SO
Cl
3
O
þ
(M
-C
6
H
4
Cl
3
SO
3
, 53). Anal. Calculated for (C16
H
9
3
5
S
2
A mixture of 4-chloroacetophenone (0.155 g, 1 mmol) and
H 2.01%. Found: C 42.46; H 2.05%.
3
[MSIm]ClSO $HCl (0.504 g, 1.6 mmol) was stirred in a sealed vial at
room temperature for 10 min. Monitoring the progress of the re-
action by TLC, using silica gel G UV/254 plates and 1:5 mixture of
ethyl acetate/n-hexane as eluent, displayed that the formation of
the intermediate product 4,6-di(4-chlorophenyl)-1,2-oxathiine-
4.2.4. 4,6-Di(4-bromophenyl)-3-(chlorosulfonyl)-1,2-oxathiine-2,2-
dioxide (3d)
ꢁ
Yield 91%. Mp ¼ 197 C. IR (KBr):
nmax 3236, 3107 (CeH Str),
2922, 1606 (C]C), 1476, 1391 and 1201 (S]O Str), 1010, 818 (SeO),
ꢀ1 1
2
,2-dioxide 2c is completed at this stage. Afterward, trifluoroacetic
3 H
608 cm . H NMR (400.2 MHz, CDCl ): d 7.70 (4H, s, Ar), 7.69 (2H,
anhydride (0.420 g, 2 mmol) was added dropwise to the reaction
mixture and stirring continued at room temperature for 3.5 h
d, J 8.8 Hz, 4-Ar 2ʹ,6ʹ-H), 7.35 (2H, d, J 8.8 Hz, 4-Ar 3ʹ,5ʹ-H), 6.57 (1H,
s, 5-H) ppm. C NMR (100.65 MHz, CDCl ): d 159.2 and, 155.7 (C-1ʹ
3 C
13
(
Table 4). After completion of the reaction, as monitored by TLC, the
and C-1ʺ), 133.0 (2CH), 132.6, 132.2 (2CH), 131.8, 129.3, 128.9 (2CH),
128.3 (2CH),127.8, 125.8,106.5 (C-5). MS (70 eV): m/z(%) ¼ 544 (M ,
þ
resulting mixture was carefully washed at least 2 times with cold
Please cite this article in press as: Toorchi Roudsari S, Rad-Moghadam K, A sulfonating ionic liquid for one-pot pseudo four-component synthesis
of novel 3-chlorosulfonyl- -sultones: A novel class of fluorescent compounds, Tetrahedron (2018), https://doi.org/10.1016/j.tet.2018.06.012
d

6
S. Toorchi Roudsari, K. Rad-Moghadam / Tetrahedron xxx (2018) 1e6
81Br 81
2
Br 37Cl, 4), 542 (M , 81Br 81Br 35Cl, 19), 540 (M , Br 79Br 35Cl,
þ
35
þ 81
(b) Wu Z, Song H, Cui X, Pi C, Du W, Wu Y. Org Lett. 2013;15:1270e1273;
(c) Qiao H, Sun S, Yang F, et al. Org Lett. 2015;17:6086e6089;
þ
79
79
þ
81
81
35
6), 538 (M , Br Br Cl, 11), 478 (M ꢀ SO
2
,
Br Br Cl, 19),
(
(
d) Kim DW, Ko YK, Kim SH. Synthesis. 1992;1992(12):1203e1204;
e) Cremlyn RJ, Swinbourne FJ, Yung KM. Heterocycl Chem. 1981;18:
þ
þ
, 81Br Br 35Cl, 25), 474 (M ꢀ SO
79
þ
, 79Br 79Br Cl, 11),
35
4
76 (M ꢀ SO
2
2
J
4
3
44 (M -SO
95 (14), 380 (M -SO
2
Cl, Br 81Br, 4), 442 (9), 440 (M -SO
81
þ
2
Cl, Br 79Br, 4),
79
997e1006;
þ
81
81
þ
(f) Fujita SS. Synthesis. 1982;1982(5):423e424.
2
Cl -SO
Br Br, 20), 376 (M -SO
Br Br, 50), 349 (M -CS
2
,
Br Br, 11), 378 (M -SO
2
Cl -SO
2
,
2
. (a) Wang L, Zhu H, Che J, Yang Y, Zhu G. Tetrahedron Lett. 2014;55:1011e1013;
b) Zeng X, Ilies L, Nakamura E. Org Lett. 2012;14:954e956;
(c) Chen C, Su J, Tong X. Chem Eur J. 2013;19:5014e5018.
3. (a) Blotny G. Tetrahedron Lett. 2003;44:1499e1501;
8
8
7
1
79
þ
þ
, 79Br Br, 3), 351 (M -CS
79
þ
þ
2
Cl -SO
2
2
O
O
5
Cl,
(
1
9
81
81
79
2
O
5
Cl, Br Br, 100), 347 (M -CS
2
5
Cl,
79
þ
81
þ
Br
Br, 53), 272 (M -C
6
H
4
BrClSO
3
,
Br, 11), 270 (M
(
(
b) Yang Z, Zhou B, Xu J. Synthesis. 2014;46:225e229;
c) Bahrami K, Khodaei MM, Soheilizad M. J Org Chem. 2009;74:9287e9291;
81
þ
-
C
6
4
H BrClSO
3
,
Br, 10), 269 (23), 252 (30), 189 (M -C
6
H
4
Br
2
ClSO
3
,
þ
35 79
81
þ
35 81
1
00), 187 (M -C
Br, 78), 183 (M -C
6
H
4
SO
3
Cl Br Br, 36), 185 (M -C
6
H
4
SO
3
Cl Br
(d) Yang Z, Zheng Y, Xu J. Synlett. 2013;24:2165e2169;
(e) Humljan J, Gobec S. Tetrahedron Lett. 2005;46:4069e4072;
8
1
þ
37
Cl81Br Br, 81), 155 (50), 113 (41),
81
6
H
4
SO
3
(f) Baker DA, East GC, Mukhopadhyay SK. J Appl Polym Sci. 2001;79:1092e1100.
9
1
9 2 5 2
4(24), 75(28). Anal. Calculated for (C16H Br ClO S ): C 35.55; H
.58%. Found: C 35.62; H 1.46%.
4
. (a) M aꢀ jek M, Neumeier M, von Wangelin AJ. ChemSusChem. 2017;10:151e155;
(b) Malet-Sanz L, Madrzak J, Ley SV, Baxendale IR. Org Biomol Chem. 2010;8:
5
324e5332.
. DeBergh JR, Niljianskul N, Buchwald SL.
0638e10641.
5
J
Am Chem Soc. 2013;135:
4
.2.5. 4,6-Di(4-iodophenyl)-3-(chlorosulfonyl)-1,2-oxathiine-2,2-
1
dioxide (3e)
Yield 78%. Mp ¼ 148 C. IR (KBr):
C]C), 1388 and 1201 (S]O Str), 1005, 981 (SeO), 814, 603 cm
6. Adams R, Marvel CS, Clarke HT, et al. Org Synth. 1921;1:21.
7. (a) Bahrami K, Khodaei MM, Abbasi J. Synthesis. 2012;2012(2):316e322;
(b) Nishiguchi A, Maeda K, Miki S. Synthesis. 2006;2006(4):4131e4134;
ꢁ
n
max 3120 (CeH Str), 2924,1608
ꢀ1
(
.
(
(
c) Bahrami K, Khodaei MM, Khaledian D. Tetrahedron Lett. 2012;53:354e358;
d) Okada T, Matsumuro H, Iwai T, et al. Chem Lett. 2015;44:185e187.
1
H NMR (400.2 MHz, CDCl
J 8.8 Hz, Ar), 7.54 (2H, d, J 8.8, Ar), 7.21 (2H, d, J 8.8, Ar), 6.58 (1H, S,
-H) ppm. 13C NMR (100.65 MHz, CDCl
): 159.4 and 155.8 (C-1ʹ
and C-1ʺ), 149.4, 138.9 (2CH), 138.2 (2CH), 131.8, 129.2 (2CH), 128.4,
28.1 (2CH), 106.4 (C-5), 102.1 and 97.8 (C-4ʹ and C-4ʺ). MS (70 eV):
3 H
): d 7.93 (2H, d, J 8.8 Hz, Ar), 7.92 (2H, d,
8. Xiao Y, Malhotra SV. J Organomet Chem. 2005;690:3609e3613.
9. Greaves TL, Drummond CJ. Chem Rev. 2015;115:11379e11448.
5
3
d
C
10. (a) Tong J, Huang L-S, Xu D-Z. New J Chem. 2017;41:3966e3974;
(b) Rad-Moghadam K, Azimi SC, Abbaspour-Gilandeh E. Tetrahedron Lett.
1
2013;54:4633e4636;
(c) Rad-Moghadam K, Sharifi-Kiasaraie M, Taheri-Amlashi H. Tetrahedron.
þ
37
þ
35
þ
37
m/z(%) ¼ 636 (M þ2, Cl, 3), 634 (M , Cl, 8), 572 (M ꢀ SO
2
,
Cl,
Cl
Cl, 22), 231
2010;66:2316e2321.
þ
35
þ
þ
3
), 570 (M ꢀ SO
2
,
Cl, 7), 536 (M þ1 -SO
Cl, 30), 472 (M -SO
2 2
1
1. (a) Amarasekara AS. Chem Rev. 2016;116:6133e6183;
(b) Mahato S, Santra S, Chatterjee R, Zyryanov GV, Hajra A, Majee A. Green
Chem. 2017;19:3282e3295.
þ
þ
-
SO
2
, 48), 443 (M -CClS
2
O
ClI
5
, 33), 317 (M -C
6
H
4
I -SO
3
þ
(
81), 189 (M
-C
6
H
4
2
SO
3
,
100). Anal. Calculated for
1
2. Zhang S, Gu Y. Functionalized ionic liquid-based catalytic systems with
diversified performance enhancements. In: Luque R, Leung-Yuk Lam F, eds.
Sustainable Catalysis: Energy-Efficient Reactions and Applications. Weinheim:
Wiley-VCH Verlag; 2018:35e58.
(
C
16
H
9
ClI ): C 30.28, H 1.43%. Found: C 30.47, H 1.58%.
2 5 2
O S
Acknowledgements
1
1
3. Cole AC, Jensen JL, Ntai I, et al. J Am Chem Soc. 2002;124:5962e5963.
4. Akiyama T. Chem Rev. 2007;107:5744e5758.
The authors are grateful to the research council of University of
Guilan for the supports of this work.
15. Shen M-H, Xu K, Sun C-H, Xu H-D. Org Lett. 2015;17:3654e3657.
16. Kemperman GJ, Roeters TA, Hilberink PW. Eur Org Chem. 2003;2003:
681e1686.
J
1
1
1
7. Chowdhury S, Mohan RS, Scott JL. Tetrahedron. 2007;63:2363e2389.
8. Rad-Moghadam K, Mousazadeh-Hassani SA, Toorchi-Roudsari S. J Mol Liq.
Appendix A. Supplementary data
2016;218:275e280.
1
2
9. Rad-Moghadam K, Toorchi Roudsari S, Sheykhan M. Synlett. 2014:827e830.
0. (a) Pustenko A, Zalubovski R. Chem Heterocycl Comp. 2017;53:1283e1285;
Supplementary data related to this article can be found at
https://doi.org/10.1016/j.tet.2018.06.012.
ꢁ
(
(
b) Mondal S, Debnath S, Das B. Tetrahedron. 2015;71:476e486;
c) Mondal S. Chem Rev. 2012;112:5339e5355.
2
2
1. Forbes WF. Can J Chem. 1960;38:1104e1112.
2. Valeur B. Molecular Fluorescence, Principles and Applications. Weinheim: Wiley-
VCH; 2002.
References
1. (a) Prakash GSK, Mathew T, Panja C, Olah GA. J Org Chem. 2007;72:5847e5850;
Please cite this article in press as: Toorchi Roudsari S, Rad-Moghadam K, A sulfonating ionic liquid for one-pot pseudo four-component synthesis
of novel 3-chlorosulfonyl- -sultones: A novel class of fluorescent compounds, Tetrahedron (2018), https://doi.org/10.1016/j.tet.2018.06.012
d