3-Carboxypyridinium chlorochromate - aluminium chloride - An efficient and inexpensive reagent system for the selective oxidation of sulfides to sulfoxides and sulfones in solution and under microwave irradiation

Article abstract of DOI:10.1139/v05-008

3-Carboxypyridinium chlorochromate (CPCC) in the presence of aluminium chloride is a very efficient reagent for the selective oxidation of sulfides to sulfoxide and sulfones in solution and under microwave irradiation. It is noteworthy that different functional groups including carbon-carbon double bonds, ketones, oximes, aldehydes, ethers, and acetals were tolerated under these reaction conditions.

Full text of DOI:10.1139/v05-008

115
3-Carboxypyridinium chlorochromate – aluminium
chloride — An efficient and inexpensive reagent
system for the selective oxidation of sulfides to
sulfoxides and sulfones in solution and under
microwave irradiation
Iraj Mohammadpoor-Baltork, Hamid R. Memarian, and Kiumars Bahrami
Abstract: 3-Carboxypyridinium chlorochromate (CPCC) in the presence of aluminium chloride is a very efficient re-
agent for the selective oxidation of sulfides to sulfoxide and sulfones in solution and under microwave irradiation. It is
noteworthy that different functional groups including carbon–carbon double bonds, ketones, oximes, aldehydes, ethers,
and acetals were tolerated under these reaction conditions.
Key words: sulfoxides, sulfones, oxidation, chlorochromate, Lewis acid.
Résumé : Le chlorochromate de 3-carboxypyridinium (CCCP) en présence de chlorure d’aluminium est un réactif très
efficace pour l’oxydation des sulfures en sulfoxydes et en sulfones effectuée en solution et sous irradiation de micro-
ondes. Il est notable que divers groupes fonctionnels, y compris les doubles liaisons carbone–carbone, les cétones, les
oximes, les aldéhydes, les éthers et les acétals, sont tolérés dans les conditions de la réaction.
Mots clés : sulfoxydes, sulfones, oxydation, chlorochromate, acide de Lewis.
[Traduit par la Rédaction] Mohammadpoor-Baltork et al. 121
Introduction
Scheme 1. (i) CPCC (0.8–1 equiv.), AlCl3 (1 equiv.), CH3CN,
reflux or MW; (ii) CPCC (1–2.5 equiv.), AlCl3 (1 equiv.),
CH3CN, reflux or MW.
Sulfoxides and sulfones are useful synthetic intermediates
for the construction of various chemically and biologically
significant molecules (1). The most popular and straightfor-
ward method for preparing sulfoxides or sulfones involves
the oxidation of sulfides. Various methods are available for
the oxidation of sulfides to sulfoxides and (or) sulfones (2–
29). However, some of these methods suffer from drawbacks
such as long reaction times, low yields of the products, the
use of expensive reagents, and undesired reactions of other
functional groups. On the other hand, selective oxidation of
sulfides to sulfoxides and sulfides to sulfones with the same
reagent system under the adjusted reaction conditions is an
important process in synthetic organic chemistry, and only a
few reports are available in the literature for this purpose
(30). Consequently, introduction of a new method and inex-
pensive reagent for the oxidation of sulfides to sulfoxides
and sulfones is still in demand. The chemoselective oxida-
tion of sulfides without affecting the other functional groups
is also another point of interest. Along this line, we wish to
report that sulfides are efficiently oxidized to their corre-
sponding sulfoxides and sulfones with 3-carboxypyridinium
chlorochromate in solution and under microwave irradiation.
Results and discussion
3-Carboxypyridinium chlorochromate (CPCC) is an inex-
pensive reagent and is easily prepared from the commer-
cially available starting materials. We have recently reported
CPCC as a convenient reagent for the oxidative cleavage
of carbon–nitrogen double bonds, oxidative deprotection of
trimethylsilyl and tetrahydropyranyl ethers, oxidation of 1,4-
dihydropyridines, and deprotection of thiocarbonyl com-
pounds (31). In the course of further exploration on the
application in synthetic organic chemistry, we found that
CPCC in the presence of aluminium chloride can be used as
an efficient reagent for the oxidation of sulfides to sulf-
oxides and sulfones (Scheme 1).
Received 20 July 2004. Published on the NRC Research Press
Web site at http://canjchem.nrc.ca on 19 February 2005.
I. Mohammadpoor-Baltork,1 H.R. Memarian, and
K. Bahrami. Department of Chemistry, Isfahan University,
Isfahan 81746-73441, Iran.
Initially, benzyl 4-methylphenyl sulfide (entry 1g, Table
1) was used as a model compound for sulfoxidation by
CPCC alone in refluxing acetonitrile. It was found that the
reaction did not proceed at all after 2 h.
1Corresponding author (e-mail: imbaltork@sci.ui.ac.ir).
Can. J. Chem. 83: 115–121 (2005)
doi: 10.1139/V05-008
© 2005 NRC Canada

116
Can. J. Chem. Vol. 83, 2005
Table 1. Oxidation of sulfides to sulfoxides using CPCC–AlCl3.
Time (min)
Solutionb
Yield (%)d
Sulfide (1)
Sulfoxide (2)a
MWc
Solution
MW
Ref.
(C6H5)2S (1a)
(C6H5)2SO (2a)
120
75
3
83
93
87
95
93
94
94
91
87
93
94
93
90
82
93
75
75
95
73
82
92
90
95
95
94
95
93
85
95
94
92
90
83
94
79
77
98
75
2
2
1.5
0.33
1
C6H5CH2SC6H5 (1b)
C6H5CH2SOC6H5 (2b)
20
2
(C6H5CH2)2S (1c)
(C6H5CH2)2SO (2c)
60
35a
35b
—
4-MeC6H4CH2SC6H5 (1d)
4-BrC6H4CH2SC6H5 (1e)
4-O2NC6H4CH2SC6H5 (1f)
4-MeC6H4SCH2C6H5 (1g)
4-BrC6H4SCH2C6H5 (1h)
4-ClC6H4SCH2C6H5 (1i)
4-BrC6H4CH2SCH2C6H5 (1j)
4-BrC6H4CH2SC6H44-Me (1k)
4-BrC6H4CH2SC6H44-Br (11)
4-BrC6H4CH2SC6H44-Cl (1m)
4-O2NC6H4CH2SC6H44-Cl (1n)
2-ClC6H4CH2SC6H44-Cl (1o)
(n-C3H7)2S (1p)
4-MeC6H4CH2SOC6H5(2d)
4-BrC6H4CH2SOC6H5 (2e)
4-O2NC6H4CH2SOC6H5 (2f)
4-MeC6H4SOCH2C6H5 (2g)
4-BrC6H4SOCH2C6H5 (2h)
4-ClC6H4SOCH2C6H5 (2i)e
4-BrC6H4CH2SOCH2C6H5 (2j)
4-BrC6H4CH2SOC6H44-Me (2k)
4-BrC6H4CH2SOC6H44-Br (2l)
4-BrC6H4CH2SOC6H44-Cl (2m)e
4-O2NC6H4CH2SOC6H44-Cl (2n)e
2-ClC6H4CH2SOC6H44-Cl (2o)
(n-C3H7)2SO (2p)e
45
0.75
0.5
0.75
2
30
40
30b
35b
30b
—
90
100
20
2
0.33
0.5
1.5
1.5
1.25
2
30
35c
35b
35b
35c
35b
34
80
80
70
100
20
0.33
0.5
3.25
4
(n-C4H9)2SO (2q)e
30
35i
—
(n-C4H9)2S (1q)
135
180
n-C8H17SCH2CH2CHMe2 (1r)
n-C8H17SOCH2CH2CHMe2 (2r)
2
Note: MW refers to microwave irradiation.
aAll products were identified by comparison of their physical and spectral data with those of authentic samples.
bSulfide:CPCC:AlCl3 = 1:1:1.
cSulfide:CPCC:AlCl3 = 1:0.8:1.
dIsolated yields.
eSulfone (3%–16%) was obtained from the reaction mixture.
Table 2. Oxidation of benzyl 4-methylpheny sulfide to benzyl 4-
methylpheny sulfoxide with CPCC in the presence of different
Lewis acids in refluxing CH3CN.
Table 3. Oxidation of benzyl 4-methylpheny sulfide to benzyl 4-
methylpheny sulfoxide with CPCC in the presence of AlCl3 in
different solvents under reflux conditions.
Solventa
Time (min)
Yield (%)b
Entry
Lewis acida
Time (min)
Yield (%)b
Entry
1
2
3
4
5
6
AlCl3
40
40
40
40
40
40
94
73
72
63
68
65
1
2
3
4
5
CH3CN
40
40
40
40
40
94
75
65
60
12
BiCl3
CH3COCH3
CHCl3
SnCl2·2H2O
NiCl2·6H2O
FeCl3·6H2O
CoCl2·6H2O
CH2Cl2
n-Hexane
aSulfide:CPCC:AlCl3 = 1:1:1.
bIsolated yields.
aSulfide:CPCC:Lewis acid = 1:1:1.
bIsolated yields.
and it was observed that CH3CN is the only solvent of
choice for this purpose (Table 3).
Recently, Lewis-acid-promoted oxidation of organic com-
pounds has been reported in the literature (32). Therefore,
the oxidation of benzyl 4-methylphenyl sulfide to the corre-
sponding sulfoxide with CPCC in the presence of different
Lewis acids such as AlCl3, BiCl3, FeCl3·6H2O, SnCl2·2H2O,
NiCl2·6H2O, and CoCl2·6H2O in refluxing acetonitrile was
investigated. The best result was achieved using AlCl3 (Ta-
ble 2).
The applicability of the CPCC–AlCl3 system was then ex-
amined for sulfoxidation of diaryl, dibenzyl, aryl benzyl,
dialkyl, and cyclic sulfides in refluxing acetonitrile. The op-
timum molar ratio of sulfide to CPCC to AlCl3 was found to
be 1:1:1. Under these conditions, the corresponding sulf-
oxides were obtained in high yields (Table 1).
Recently, there has been a growing interest in the applica-
tion of microwave irradiation in chemical reactions (33). The
salient features of the microwave approach are the much im-
We have also examined this reaction in different solvents
such as CH2Cl2, CHCl3, CH3CN, CH3COCH3, and n-hexane,
© 2005 NRC Canada

Mohammadpoor-Baltork et al.
117
proved reaction rates, formation of cleaner products, and op-
erational simplicity. Therefore, the sulfoxidation of the
above-mentioned sulfides with CPCC–AlCl3 was performed
under microwave irradiation with a dramatic reduction of re-
action time. Under these conditions, the optimum molar ra-
tio of sulfide to CPCC to AlCl3 was found to be 1:0.8:1.
When the sulfides, dissolved in 2 mL of CH3CN, were
treated with CPCC–AlCl3 and irradiated for 0.33–4 min, the
corresponding sulfoxides were obtained in high yields (Ta-
ble 1).
However, in the oxidation of alkyl aryl sulfides such as 4-
chlorophenyl methyl sulfide and methyl phenyl sulfide, a
mixture of sulfoxide (~55%) and sulfone (~40%) were iso-
lated from the reaction mixture.
sulfides in the presence of the above-mentioned functional
groups in multifunctional molecules.
To show the advantage of 3-carboxypyridinium chloro-
chromate (CPCC) over pyridinium chlorochromate (PCC),
we compared the results obtained for some of the reactions
using these two reagents. It was found that the yields of the
reactions are higher with CPCC (Table 5).
In conclusion, we have demonstrated that the CPCC–
AlCl3 system is an inexpensive and excellent reagent for the
oxidation of a variety of structurally diverse sulfides to their
corresponding sulfoxides and sulfones. It is noteworthy that
the reaction can tolerate oxidatively sensitive functional
groups and that the sulfur atom is selectively oxidized.
To show the efficiency and applicability of the CPCC–
AlCl3 system further, the oxidation of sulfides to their corre-
sponding sulfones was also carried out in solution and under
microwave irradiation. The reaction conditions specified in
Table 4 were optimized for use in both solution (sulfide to
CPCC to AlCl3 = 1:1.5–2.5:1) and under microwave irradia-
tion (sulfide to CPCC to AlCl3 = 1:1–2:1). It was found that
a wide variety of diaryl, dialkyl, dibenzyl, aryl benzyl, alkyl
aryl, and cyclic sulfides were oxidized to their sulfones in
excellent yields in refluxing acetonitriles. It should be noted
that some of these oxidation reactions were also performed
in dry acetonitrile and no improvement was observed under
these conditions. The oxidation of these sulfides with the
CPCC–AlCl3 system under microwave irradiation afforded
the corresponding sulfones in excellent yields in very short
reaction times (0.25–4.5 min) without any special precau-
tions. The results are presented in Table 4. Under microwave
irradiation, acetonitrile was used for the homogenization of
the reaction mixture. The polar character of this solvent also
seems to increase the reaction temperature, so the reaction is
completed in a short time (33c). Inspection of the data in Ta-
bles 1 and 4 show that the yields of the reactions in solution
and under microwave irradiation are comparable, but under
microwave irradiation, the reaction times are considerably
shorter. Also, the molar ratio of CPCC to sulfide is lower
under microwave irradiation.
We investigated some of these reactions with 3-
carboxypyridine–AlCl3 and it was found that the reactions
did not proceed at all. Also, during the reaction with CPCC,
the colour of the mixture turned from yellow-orange to green.
Further, the reaction times and yields were comparable when
the reactions were carried out in air and under an inert atmo-
sphere. These are good indications that the oxygens trans-
ferred to sulfides are those bound to chromium in the CPCC
reagent.
As mentioned in our previous publications (32), some of
the reagents under investigation were effective oxidizing
agents only in the presence of aluminium chloride. This
trend has been also observed in the oxidation of sulfides
with CPCC. Unfortunately, we have not been able to assign
a reasonable mechanism for these reactions at present.
It is worth mentioning that the CPCC–AlCl3 system is
chemoselective, tolerating various functional groups such as
carbon–carbon double bonds, ketones (Table 4, entries 1t,
1c′, and 1d′), oximes, aldehydes, ethers, and acetals
(Scheme 2). These observations clearly suggest that this
method can be applied for the chemoselective oxidation of
Experimental
The sulfides 1a, 1p, 1q, 1s, 1t, and 1d′ were purchased
from the Merck chemical company. The other sulfides were
prepared according to the described procedure (34). Micro-
wave irradiation was carried out using a commercial micro-
wave oven (Samsung M9G45) operating at 2450 MHz (900 W).
The yields refer to isolated pure products. Melting points
were determined using a Mettler FP5 apparatus and are un-
corrected. IR spectra were run on a Philips PU9716 spectro-
1
photometer. H NMR spectra were recorded on a Bruker 80
or 200 and (or) 500 MHz spectrometer with CDCl3 as the
solvent and TMS as the internal standard. The elemental
analysis was performed by the Research Institute of Petro-
leum Industry, Tehran, Iran. CPCC was prepared according
to the reported procedure (31a).
General procedure for the oxidation of sulfides to
sulfoxides in solution
In a round-bottomed flask (50 mL) equipped with a con-
denser and a magnetic stirrer, a solution of sulfide (1 mmol)
in CH3CN (10 mL) was prepared. CPCC (1 mmol) and
AlCl3 (1 mmol) were added and the mixture was stirred un-
der reflux conditions for the time indicated in Table 1. The
progress of the reaction was monitored by TLC (eluent: n-
hexane – ethyl acetate, 7:2). The mixture was filtered and
the solid material was washed with CH3CN (10 mL). The
filtrate was evaporated and the crude product was purified
by recrystallization or chromatography on silica gel to afford
the pure sulfoxide (Table 1).
General procedure for the oxidation of sulfides to
sulfoxides under microwave irradiation
A mixture of sulfide (1 mmol), CPCC (0.8 mmol), and
AlCl3 (1 mmol) and CH3CN (2 mL) was exposed to micro-
wave irradiation (900 W) for 0.33–4 min (at 20 s intervals).
The progress of the reaction was followed by TLC. After
completion of the reaction, the mixture was extracted with
ethyl acetate (2 × 20 mL). Evaporation of the solvent fol-
lowed by recrystallization or chromatography on silica gel
afforded the pure sulfoxide (Table 1).
General procedure for the oxidation of sulfides to
sulfones in solution
To a solution of sulfide (1 mmol) in CH3CN (10 mL) in a
round-bottomed flask (50 mL) equipped with a condenser
and a magnetic stirrer, CPCC (1.5–2.5 mmol) and AlCl3
© 2005 NRC Canada

118
Can. J. Chem. Vol. 83, 2005
Table 4. Oxidation of sulfides to sulfones using CPCC–AlCl3.
Time (min)
Solutionb
Yield (%)d
Sulfide (1)
Sulfone (3)a
MWc
Solution
MW
Ref.
(C6H5)2S (1a)
(C6H5)2SO2 (3a)
120
65
3
1
95
97
96
96
95
98
95
96
94
95
95
95
94
95
93
92
95
94
92
95
99
97
95
98
98
95
97
94
99
97
95
95
95
94
95
95
96
95
35i
30a
34
C6H5CH2SC6H5 (1b)
C6H5CH2SO2C6H5 (3b)
30
0.5
1
(C6H5CH2)2S (1c)
(C6H5CH2)2SO2 (3c)
60
35d
35d
—
4-MeC6H4CH2SC6H5 (1d)
4-BrC6H4CH2SC6H5 (1e)
4-O2NC6H4CH2SC6H5 (1f)
4-MeC6H4SCH2C6H5 (1g)
4-BrC6H4SCH2C6H5 (1h)
4-ClC6H4SCH2C6H5 (1i)
4-BrC6H4CH2SCH2C6H5 (1j)
4-BrC6H4CH2SC6H44-Me (1k)
4-BrC6H4CH2SC6H44-Br (1l)
4-BrC6H4CH2SC6H44-Cl (1m)
4-O2NC6H4CH2SC6H44-Cl (1n)
2-ClC6H4CH2SC6H44-Cl (1o)
(n-C3H7)2S (1p)
4-MeC6H4CH2SO2C6H5 (3d)
4-BrC6H4CH2SO2C6H5 (3e)
4-O2NC6H4CH2SO2C6H5 (3f)
4-MeC6H4SO2CH2C6H5 (3g)
4-BrC6H4SO2CH2C6H5 (3h)
4-ClC6H4SO2CH2C6H5 (3i)
4-BrC6H4CH2SO2CH2C6H5 (3j)
4-BrC6H4CH2SO2C6H44-Me (3k)
4-BrC6H4CH2SO2C6H44-Br (3l)
4-BrC6H4CH2SO2C6H44-Cl (3m)
4-O2NC6H4CH2SO2C6H44-Cl (3n)
2-ClC6H4CH2SO2C6H44-Cl (3o)
(n-C3H7)2SO2 (3p)
60
1
40
0.75
1
60
30b
35b
30b
—
100
100
30
2.5
2.5
2.5
0.75
2.5
2.5
1
45
35c
35b
35b
35c
35b
34
100
110
60
120
50
2.5
1
90
2
35i
—
(n-C4H9)2S (1q)
(n-C4H9)2SO2 (3q)
120
180
3
n-C8H17SCH2CH2CHMe2 (1r)
n-C8H17SO2CH2CH2CHMe2 (3r)
4
35i
200
4.5
91
93
35g
60
60
30
20
100
45
60
65
30
5
1
95
94
94
91
94
92
96
92
91
94
94
94
96
92
94
95
95
92
94
97
—
n-C8H17SMe (1u)
n-C8H17SO2Me (3u)
1
—
n-C8H17SCH2CH3 (1v)
C6H5SMe (1w)
n-C8H17SO2CH2CH3 (3v)
C6H5SO2Me (3w)
0.5
0.33
2.5
0.75
1
30b
35h
—
4-MeC6H4SMe (1x)
4-ClC6H4SMe (1y)
C6H5S(n-C3H7) (1z)
C6H5S(n-C4H9) (1a′)
C6H5SCHMe2 (1b′)
C6H5SCH2CH=CH2 (1c′)
(CH2=CHCH2)2S (1d′)
4-MeC6H4SO2Me (3x)
4-ClC6H4SO2Me (3y)
C6H4SO2(n-C3H7) (3z)
C6H5SO2(n-C4H9) (3a′)
C6H5SO2CHMe2 (3b′)
C6H5SO2CH2CH=CH2 (3c′)
(CH2=CHCH2)2SO2 (3d′)
35e
35e
35e
30b
35f
1
0.5
0.25
Note: MW refers to microwave irradiation.
aAll products were identified by comparison of their physical and spectral data with those of authentic samples.
bSulfide:CPCC:AlCl3 = 1:2.5:1 and 1:1.5:1 for entries 1a–1v and 1w–1d′, respectively.
cSulfide:CPCC:AlCl3 = 1:2:1 and 1:1:1 for entries 1a–1v and 1w–1d′, respectively.
dIsolated yields.
(1 mmol) were added and the mixture was stirred under re-
flux conditions for the appropriate time according to Ta-
ble 4. The progress of the reaction was monitored by TLC
(eluent: n-hexane – ethyl acetate, 7:1). The reaction mixture
was filtered and the solid material was washed with CH3CN
(10 mL). Evaporation of the solvent, followed by recrystalli-
zation or chromatography on silica gel afforded the pure
sulfone (Table 4).
General procedure for the oxidation of sulfides to
sulfones under microwave irradiation
A mixture of sulfide (1 mmol), CPCC (1 to 2 mmol),
AlCl3 (1 mmol), and CH3CN (2 mL) was prepared. The mix-
ture was irradiated (900 W) for 0.25–4.5 min (at 20 s inter-
vals) and the completion of the reaction was monitored by
TLC examination. After completion of the reaction, the mix-
ture was extracted with ethyl acetate (2 × 20 mL). The
© 2005 NRC Canada

Mohammadpoor-Baltork et al.
119
Scheme 2. A = CPCC:substrates:AlCl3 = 1:1:1:1, CH3CN, reflux; B = CPCC:substrates:AlCl3 = 0.8:1:1:1, CH3CN, MW; C =
CPCC:substrates:AlCl3 = 2.5:1:1:1, CH3CN, reflux; D = CPCC:substrates:AlCl3 2:1:1:1, CH3CN, MW.
59.76, H 4.24, N 5.36, S 12.27; found: C 59.63, H 4.40, N
5.25, S 12.41.
Table 5. Comparison of some of the results obtained with CPCC
and PCC.
Compound 2j: mp 139 to 140 °C. IR νmax (KBr, cm–1):
CPCC: Yield%a
(time, min)
PCC: Yield%a
(time, min)
1
1028. H NMR (500 MHz, CDCl3) δH: 7.54 (d, J = 8.27 Hz,
2H, Ph-H), 7.44–7.40 (m, 3H, Ph-H), 7.33–7.32 (m, 2H, Ph-
H), 7.2 (d, J = 8.27 Hz, 2H, Ph-H), 3.95 (s, 2H, CH2), 3.89
(d, J = 13.09 Hz, 1H, CH2), 3.78 (d, J = 13.09 Hz, 1H,
CH2). Anal. calcd. for C14H13SOBr: C 54.38, H 4.24, S
10.37; found: C 54.30, H 4.22, S 10.50.
Substrate Product Solution MW
Solution MW
1c
1e
1c
1e
2c
2e
3c
3e
87 (20)
93 (45)
96 (30)
95 (60)
90 (0.33) 65 (20)
95 (0.75) 70 (45)
70 (0.33)
74 (0.75)
78 (0.5)
74 (1)
97 (0.5)
98 (1)
75 (30)
73 (60)
Compound 2r: mp 42 to 43 °C. IR νmax (KBr, cm–1):
1
1018. H NMR (200 MHz, CDCl3) δH: 2.80–2.55 (m, 4H,
Note: MW refers to microwave irradiation.
aIsolated yields.
-CH2-SO-CH2-), 1.90–1.60 (m, 5H, 2CH2, CH), 1.50–1.15
(m, 10H, 5CH2), 0.94–0.88 (m, 9H, 3CH3). Anal. calcd. for
C13H28SO: C 67.18, H 12.14, S 13.80; found: C 66.98, H
12.08, S 14.10.
solvent was evaporated and purification was achieved by
recrystallization or chromatography on silica gel to afford
the pure sulfone (Table 4).
Compound 3f: mp 204 to 205 °C. IR νmax (KBr, cm–1):
1
1515, 1345, 1300, 1142. H NMR (200 MHz, CDCl3) δH:
8.18 (d, J = 6.5 Hz, 2H, Ph-H), 7.70–7.40 (m, 5H, Ph-H),
7.10 (d, J = 6.5 Hz, 2H, Ph-H), 4.44 (s, 2H, CH2). Anal.
calcd. for C13H11NSO4: C 56.31, H 3.99, N 5.05, S 11.56;
found: C 56.17, H 4.10, N 4.96, S 11.75.
Spectroscopic data
Compound 2f: mp 161–163 °C. IR νmax (KBr, cm–1):
1
1515, 1345, 1026. H NMR (200 MHz, CDCl3) δH: 8.12 (d,
J = 6.5 Hz, 2H, Ph-H), 7.51–7.40 (m, 5H, Ph-H), 7.13 (d,
J = 6.5 Hz, 2H, Ph-H), 4.24 (d, J = 12.0 Hz, 1H, CH2), 4.04
(d, J = 12.0 Hz, 1H, CH2). Anal. calcd. for C13H11NSO3: C
Compound 3j: mp 176–178 °C. IR νmax (KBr, cm–1):
1
1299, 1116. H NMR (80 MHz, CDCl3) δH: 7.60–7.17 (m,
© 2005 NRC Canada

120
Can. J. Chem. Vol. 83, 2005
A.E. Ruoho. Phosphorus Sulfur Silicon Relat. Elem. 178, 2441
(2003).
9H, Ph-H), 4.14 (s, 2H, CH2), 4.02 (s, 2H, CH2). Anal.
calcd. for C14H13BrSO2: C 51.70, H 4.03, S 9.86; found: C
51.60, H 4.10, S 9.97.
19. B. Pelotier, M.S. Anson, I.B. Campbell, S.J.F. Macdonald, G.
Priem, and R.F.W. Jackson. Synlett, 1055 (2002).
20. S.S. Kim, K. Nehru, S.S. Kim, D.W. Kim, and H.C. Jung. Syn-
thesis, 2484 (2002).
21. (a) H. Firouzabadi and M. Seddighi. Synth. Commun. 21, 211
(1991); (b) H. Firouzabadi and I. Mohammadpoor-Baltork.
Bull. Chem. Soc. Jpn. 65, 1131 (1992); (c) N. Iranpoor, H.
Firouzabadi, and A.-R. Pourali. Tetrahedron, 58, 5179 (2002);
(d) N. Iranpoor, H. Firouzabadi, and A.-R. Pourali. Synlett,
347 (2004).
Compound 3r: mp 39–41 °C. IR νmax (KBr, cm–1): 1266,
1
1110. H NMR (80 MHz, CDCl3) δH: 2.90–2.65 (m, 4H,
-CH2-SO2-CH2-), 1.90–0.80 (m, 24H, alkyl). Anal. calcd. for
C13H28SO2: C 62.85, H 11.36, S 12.91; found: C 62.70, H
11.45, S 13.10.
Compound 3u: mp 63 to 64 °C. IR νmax (KBr, cm–1):
1
1275, 1122. H NMR (80 MHz, CDCl3) δH: 3.0–2.70 (m,
5H, -CH2-SO2-CH3), 1.85–0.80 (m, 15H, alkyl). Anal. calcd.
for C9H20SO2: C 56.21, H 10.48, S 16.67; found: C 56.15, H
10.40, S 16.85.
22. G. Kar, A.K. Saikia, U. Bora, S.K. Dehury, and M.K.
Chaudhuri. Tetrahedron Lett. 44, 4503 (2003).
23. W.L. Xu, Y.Z. Li, Q.S. Zhang, and H.S. Zhu. Synthesis, 227
(2004).
24. B.M. Trost and D.P. Curran. Tetrahedron Lett. 22, 1287 (1981).
25. K.R. Guertin and A.S. Kende. Tetrahedron Lett. 34, 5369 (1993).
26. V. Khanna, G.C. Maikap, and J. Iqbal. Tetrahedron Lett. 37,
3367 (1996).
27. M.H. Ali and G.J. Bohnert. Synth. Commun. 28, 2983 (1998).
28. D.H.R. Barton, W. Li, and J.A. Smith. Tetrahedron Lett. 39,
7055 (1998).
Compound 3v: mp 66 to 67 °C. IR νmax (KBr, cm–1):
1
1272, 1114. H NMR (80 MHz, CDCl3) δH: 3.0–2.65 (m,
4H, -CH2-SO2-CH2-), 1.85–0.80 (m, 18H, CH3, alkyl). Anal.
calcd. for C10H22SO2: C 58.21, H 10.74, S 15.54; found: C
58.20, H 10.70, S 15.65.
Compound 3y: mp 95–97 °C. IR νmax (KBr, cm–1): 1304,
1
1142. H NMR (500 MHz, CDCl3) δH: 7.90 (d, J = 8.5 Hz,
2H, Ph-H), 7.60 (d, J = 8.5 Hz, 2H, Ph-H), 3.10 (s, 3H,
CH3). Anal. calcd. for C7H7ClSO2: C 44.10, H 3.70, S
16.82; found: C 43.90 H 3.80, S 17.10.
29. D.A. Alonso, C. Najera, and M. Varea. Tetrahedron Lett. 43,
3459 (2002).
30. (a) C.G. Venier, T.G. Squires, Y.-Y. Chen, G.P. Hussmann, J.C.
Shei, and B.F. Smith. J. Org. Chem. 47, 3773 (1982); (b) B.M.
Choudary, B. Bharathi, C.V. Reddy, and M.L. Kantam. J.
Chem. Soc. Perkin Trans. 1, 2069 (2002); (c) A. McKillop and
J.A. Tarbin. Tetrahedron Lett. 24, 1505 (1983); (d) R.P.
Greenhalgh. Synlett, 235 (1992); (e) S. Yamazaki. Bull. Chem.
Soc. Jpn. 69, 2955 (1996); (f) R.S. Varma, R.K. Saini, and
H.M. Meshram. Tetrahedron Lett. 38, 6525 (1997).
31. (a) I. Mohammadpoor-Baltork and Sh. Pouranshirvani. Synth.
Commun. 26, 1 (1996); (b) I. Mohammadpoor-Baltork and Sh.
Pouranshirvani. Synthesis, 756 (1997); (c) I. Mohammadpoor-
Baltork, M.M. Sadeghi, H.R. Memarian, and R. Pairow J.
Chem. Res. (S), 40 (2000); (d) I. Mohammadpoor-Baltork,
H.R. Memarian, and K. Bahrami. Monatsh. Chem. 135, 411
(2004).
32. (a) H. Firouzabadi and I. Mohammadpoor-Baltork. Synth.
Commun. 24, 1065 (1994); (b) H. Firouzabadi and I.
Mohammadpoor-Baltork. Bull. Chem. Soc. Jpn. 68, 2319
(1995); (c) H. Firouzabadi, A.R. Sardarian, and H. Badparva.
Bull. Chem. Soc. Jpn. 69, 685 (1996); (d) I. Mohammadpoor-
Baltork and A.R. Nourozi. Synthesis, 487 (1999); (e) I.
Mohammadpoor-Baltork, M.M. Sadeghi, and A.-H. Adibi.
Molecules, 900 (2001); (f) M. Gholizadeh, I. Mohammadpoor-
Baltork, and B. Kharamesh. Bull. Korean Chem. Soc. 25, 566
(2004).
Acknowledgments
We are thankful to the Isfahan University Research Coun-
cil for partial support of this work.
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