Metal and solvent free selective oxidation of sulfides to sulfone using bifunctional ionic liquid [pmim]IO4

Article abstract of DOI:10.1016/j.tetlet.2014.11.089

The oxidation of organo-sulfides to sulfones has been accomplished using an easily accessible bifunctional ionic liquid, [pmim]IO₄ in the absence of any other oxidants, metal and organic solvent at ambient temperature. A variety of sulfides including dialkyl, aryl-alkyl, diaryl, and aryl-hetero aryl have been oxidized to the corresponding functionalized sulfones in high yields by this procedure.

Full text of DOI:10.1016/j.tetlet.2014.11.089

Accepted Manuscript
Metal and solvent free selective oxidation of sulfides to sulfone using bifunc-
tional ionic liquid [pmim]IO
4
Sabir Ahammed, Debasish Kundu, Mohammad Nahid Siddiqui, Brindaban C.
Ranu
PII:
S0040-4039(14)01993-5
DOI:
http://dx.doi.org/10.1016/j.tetlet.2014.11.089
TETL 45473
Reference:
To appear in:
Tetrahedron Letters
Received Date:
Revised Date:
Accepted Date:
3 November 2014
17 November 2014
18 November 2014
Please cite this article as: Ahammed, S., Kundu, D., Nahid Siddiqui, M., Ranu, B.C., Metal and solvent free selective
oxidation of sulfides to sulfone using bifunctional ionic liquid [pmim]IO , Tetrahedron Letters (2014), doi: http://
4
dx.doi.org/10.1016/j.tetlet.2014.11.089
This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers
we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and
review of the resulting proof before it is published in its final form. Please note that during the production process
errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

Graphical Abstract
Metal and solvent free selective
oxidation of sulfides to sulfone using
bifunctional ionic liquid [pmim]IO
4
a
a
b
a
Sabir Ahammed , Debasish Kundu , Mohammad Nahid Siddiqui and Brindaban C. Ranu*

Metal and solvent free selective oxidation of sulfides to sulfone using
bifunctional ionic liquid [pmim]IO4
a
a
b
a
Sabir Ahammed , Debasish Kundu , Mohammad Nahid Siddiqui and Brindaban C. Ranu*
a
Department of Organic Chemistry, Indian Association for the Cultivation of Science, Jadavpur, Kolkata-700032, India. E-mail:
ocbcr@iacs.res.in; Fax: (+91) 33-24732805; Tel: (+91) 33-24734971.
b
Department of Chemistry, King Fahd University of Petroleum & Minerals, Dhahran 31261, Saudi Arabia.
ABSTRACT: The oxidation of organo-sulfides to sulfones has been accomplished using an easily accessible bifunctional
ionic liquid, [pmim]IO in the absence of any other oxidants, metal and organic solvent at ambient temperature. A variety
4
of sulfides including dialkyl, aryl-alkyl, diaryl, aryl-hetero aryl have been oxidized to the corresponding functionalized
sulfones in high yields by this procedure.
Keywords: Ionic liquid, Suifide, Sulfone, organic solvent free,oxidation
1
The selective oxidation of sulfide to sulfone has considerable significance in biology and pharmaceutical industry. The
derivatives of heteroaryl sulfones constitute core units of many potent molecules which were used as drugs and potential
2
3
precursors (Figure 1). Sulfones are very useful reagents in organic synthesis particularly in asymmetric organocatalysis.
In addition, polymeric sulfones are attractive functional materials having excellent thermal stability and good electrical
4
properties. Moreover, oxidative desulfurization processes for obtaining ultra low sulfur fuels involve oxidation of sulfides
5
to sulfones.
Figure 1. Biologically active sulfone and its analogue
Oxidation of organo-sulfur compound also finds application in the removal of sulfur-containing pollutants during air and
6
waste water treatment. Thus, synthesis of functionalized sulfones is of considerable interest. A variety of oxidizing
2 2
agents have been used for the oxidation of sulfides to sulfones. H O in combination with various metal salts has been
7
8
9
10
11
12
widely used. Some of the other oxidizing agents include polyvalent iodine, oxone, ozone, aqueous NaOCl, oxygen,
13
4
14
15
NaIO
and others. The oxidations were carried out in different organic solvents, supercritical carbon dioxide and ionic
16
17
liquid. Ionic liquids have received much attention due to their negligible volatility, and other advantageous properties.
18
4
We report here a novel approach using a bifunctional ionic liquid [pmim]IO
for the selective oxidation of organosulfides
to sulfones in neat in absence of any solvent, metal and co-oxidant (Scheme 1).

Previous report
H O , Peracid,
SeO , bromate
2
2
2
O
O
various metal
S
S
R1
R2
bifunctional
[pmim]IO4
ionic liquid
R1
R2
This work
Scheme 1. Oxidation of sulfide using oxidative ionic liquid
To standardize the reaction conditions a series of experiments were performed with the variation of amount of IL, reaction
4
temperature and time for a representative oxidation of diphenyl sulfide using [pmim]IO . The reaction produced either
sulphoxide or a mixture of sulphoxide and sulfone at varying amounts (Table 1, entries 1-4). Best result leading to
Table 1. Optimization of reaction conditions
o
a
Entry
IL (equiv.)
Temp.( C)
Time (h)
Yield (%)
1
2
3
4
5
6
7
8
9
2
3
3
4
4
4
5
5
5
rt
rt
4
4
6
6
5
4
4
5
4
8
18
23
28
56
81
92
52
rt
rt
50
50
rt
50
50
80
88
b
1
0
25
c
1
1
80 13
8
11
a
1
b
Yields refer to those of purified products characterized by IR and H and C NMR spectroscopic data. NaIO
4
(3 equiv.) as additive and H
2
O as
c
a solvent used. NaIO
4
(3 equiv.) as an additive and DMF as a solvent used.
o
selective oxidation to sulfone was achieved using 4 equivalents of ionic liquid at 50 C for 4 h (Table 1, entry 6). When we
4
carried out a blank reaction in water and DMF separately using NaIO as an oxidizing agent in absence of IL, the reaction
o
did not go well even after prolonged heating (80 C, 8 h) (Table 1, entries 10 and 11). Thus it is likely that ionic liquid has
-
4
an effect on the activation of IO
ion in the oxidation of sulfide.
A series of diversely substituted sulfides were subjected to oxidation by the standardized reaction conditions. The results
are summarized in Table 2. Both aliphatic and aromatic sulfides were efficiently converted into their respective sulfones
with excellent chemoselectivity although aliphatic sulfides took longer time than aromatic ones. Several functional groups
and moieties such as -Me, -OMe, -Br, -Cl, -F, - COMe, -NO
procedure. Even, an easily oxidizable –CHO group survives under these reaction conditions using [pmim]IO
n). It is noteworthy that the aryl sulfides substituted with electron-donating groups gave higher yields compared to those
bearing electron-withdrawing substituents. The hindered (2,6-dimethoxyphenyl)(2,6-dimethylphenyl)sulfane (Table 2, 3l)
underwent facile oxidation with [pmim]IO to produce corresponding sulfone without any difficulty. Several
2
, -CN, double bond, triple bond were compatible with this
4
(Table 2,
3
4

a
Table 2. Oxidation of sulfides to sulfone using [pmim]IO
4
ionic liquid
O O
S
O O
S
O O
S
O O
S
1
7
17
OMe
Me
3a, 88%
3b, 92%
3c, 91%
3d, 93%
O O
S
O O
S
O O
S
Me Cl
3e, 92%
3f, 88%
3g, 91% Me
O O
S
O O
S
O O
S
F
Br
Cl
CO Et
2
NC
Cl
Cl
3
i, 84%
3
h, 75%
3j, 91%
O O
S
O O OMe
S
O O
S
Br
Cl
NO
2
MeO
3
k, 78%
3l, 88%
3m, 76%
O O
S
O O
S
NO
O O
S
2
Br
CHO
Me
Cl
Cl
3o, 81%
3p, 82%
3n, 81%
O O
S
O O
S
MeO
MeO
3q, 91%
3r, 85%
a
Reaction condition: diphenyl sulphide (1 mmol), [pmim]IO
4
ionic liquid (4 equiv.).
b
1
Yields refer to those of purified products characterized by IR and H and
1
3
C NMR spectroscopic data
a
Table 3. Synthesis of heterocyclic sulfone
O O
S
O O
S
O O
S
S
N
Me
S
COMe
N
N
Me
O
F C
3
4
a, 91%
4b, 78%
4c, 77%
O
S
S
S
N
N
N
S
O O
4
d, 74%
4e, 82%
a
Reaction condition: diphenyl sulphide (1 mmol), [pmim]IO
4
ionic liquid (4 equiv.).
b
1
13
Yields refer to those of purified products characterized by IR and H and C NMR spectroscopic data.

unsymmetrical heteroaryl-heteroaryl sulfides containing thiophenyl, pyridinyl, thiazolyl, benzothiazolyl,
dibenzothiophenyl moieties underwent oxidation to produce the corresponding sulfones (Table 3). Thus, this procedure is
efficient enough for the oxidation of heteroaryl sulfides, which was not addressed earlier. The reduction is uniform with o-
,
m-, p- substituted aryl sulfides. We also investigated the oxidation of a disulfide, thianthrene (Scheme 2). We observed
that use of 4 equiv. of ionic liquid led to the oxidation of one sulfide moiety keeping another unchanged. However use of
excess ionic liquid (8 equiv.) makes both sulfide moieties to disulfone.
4
We assume that the oxidation is mediated by the IO counter ion of the ionic liquid following the standard reaction path
1
9
way.
Scheme 2. Mono and di-oxidation of thianthrene.
A highly chemo-selective and efficient method for the oxidation of sulfides to the corresponding sulfones using an
20
4
oxidizing [pmim]IO ionic liquid in absence of any solvent, catalyst or external oxidising agent has been developed. The
simplicity in operation, general applicability, mild conditions and wide substrate scope make this procedure more
attractive. We believe, this will find useful applications in organic synthesis.
Acknowledgments
We are pleased to acknowledge the financial support from DST, New Delhi, in the form of the award J.C. Bose National
Fellowship to B.C.R. (Grant No. SR/S2/JCB-11/2008). S.A. and D.K. thank CSIR, New Delhi, for their fellowships.
References and notes
1
2
3
4
.
.
.
.
Carreno, M. C. Chem. Rev., 1995, 95, 1717; (b) Fernandez, I.; Khiar, N. Chem. Rev., 2003, 103, 365; (c) Wojaczynska, E.;
Wojaczynski, J. Chem. Rev., 2010, 110, 4303; (d) Stingl, K. A.; S. Tsogoeva, B. Tetrahedron: Asymmetry, 2010, 21, 1055.
(a) Takeo, M.; Kazue, Y.; Takeshi N.; Keiichi, I.; Kuniomi, M.;
Tetsu, W. Jpn. Tokkyo Koho, JP 63284104 A 19881121, 1988;
(b) Matsuo, M.; Ogino, T.; Tsuji, K. PCT Int. Appl. WO9630370A2 19961003, 1996.
(a) Nielsen, M.; Jacobsen, C. B.; Holub, N.; Paixão, M. W.; Jørgensen, K. A. Angew. Chem., Int. Ed., 2010, 49, 2668; (b) Alba, A.-N.
R.; Companyó, X.; Rios, R. Chem. Soc. Rev., 2010, 39, 2018.
Fink, J. K. High Performace Polymers, William Andrew Inc., Norwich, NY, 2008.

5
.
(a) Zhu, W.; Zhu, G.; Li, H.; Chao, Y.; Chang, Y.; Chen, G.; Han, C. J. Mol. Catal. A: Chem. 2011, 347, 8; (b) Maurya, M. R.; Arya,
A.; Kumar, A.; Kuznetsov, M. L.; Avecilla, F.; Pessoa, J. C. Inorg. Chem. 2010, 49, 6586. (c) Hulea, V.; Fajula, F.; Bousquet, J. J.
Catal. 2001, 198, 179. (d) Anisimov, A.V.; Tarakanova, A.V. Russ. J. Gen. Chem. 2009, 79, 1264.
6
7
.
.
Karmee, S. K.; Greiner, L.; Kraynov, A.; Muller, T. E.; Niemeijera, B.; Leitner, W. Chem. Commun. 2010, 46, 6705.
(a) Hirano, M.; Yakabe, S.; Clark, J. H.; Kudo, H. Morimoto, T. Synth. Commun., 1996, 26, 1875; (b) Choudary, B. M.; Reddy, C. R.
V.; Prakash, B. V.; Kantam, M. L.; Sreedhar, B. Chem. Commun., 2003, 754; (c) Matteucci, M.; Bhalay, G.; Bradley, M. Org. Lett.,
2
003, 5, 235; (d) Capozzi, M. A. M.; Centrone, C.; Fracchiolla, G.; Naso, F.; Cardellicchio, C. Eur. J. Org. Chem., 2011, 4327; (e)
Jain, S. L.; Rana, B. S.; Singh, B.; Sinha, A. K.; Bhaumik, A.; Nandi, M.; Sain, B. Green Chem., 2010, 12, 374; (f) Arterburn, J. B.;
Nelson, S. L. J. Org. Chem., 1996, 61, 2260; (g) Zhou, X. T.; Ji, H. B.; Cheng, Z.; Xu, J. C.; Pei, L. X.; Wang, L. F. Bioorg. Med.
Chem. Lett., 2007, 17, 4650; (g) Xu, L.; Cheng, J.; Trudell, M. L. J. Org. Chem., 2003, 68, 5388; (h) Bordoloi, A.; Vinu, A.;
Halligudi, S. B. Chem. Commun., 2007, 4806; (i) Gamba, I.; Palavicini, S.; Monzani, E.; Casella, L. Chem.–Eur. J., 2009, 15, 12932;
(j) Legros, J.; Bolm, C. Angew. Chem., Int. Ed., 2003, 42, 5487.
8
.
.
(a) Qian, W.; Pei, L. Synlett, 2006, 709. (b) Barton, D. H. R.; Li, W.; Smith, J. A. Tetrahedron Lett., 1998, 39, 7055. (c) Xu, L.;
Cheng, J.; Trudell, M. L. J. Org. Chem., 2003, 68, 5388. (d) Zweifel, T.; Nielsen, M.; Overgaard, J.; Jacobsen, C. B.; Jørgensen, K. A.
Eur. J. Org. Chem., 2011, 47.
9
1
1
1
1
1
Yu, B.; Liu, A.-H.; He, L. –N.; Li, B.; Diao, Z. –F.; Li. Y,-N.; Green Chem., 2012, 14, 957.
0. Irfan, M.; Glasnov, T. N.; Kappe, C. O. Org. Lett., 2011, 13, 984.
1. Fukuda, N.; Ikemoto. T. J. Org. Chem. 2010, 75, 4629.
2. Chinnusamy, T.; Reiser, O. ChemSusChem, 2010, 3, 1040.
3. (a) Leonard, N. J.; Johnson, C. R. J. Org. Chem. 1962, 27, 282; (b) Hiskey, R.G.; Harpold, M. A. J. Org. Chem. 1967, 32, 3191.
4. (a) Mernikov, N. N. Uspekhi Khim. 1936, 5, 443. (b) Moorthy, J. N.; Senapati, K.; Parida, K. N. J. Org. Chem., 2010, 75, 8416; (c)
Moorthy, J. N.; Senapati, K.; Parida, K. N.; Jhulki, S.; Sooraj, K.; Nair, N. N. J. Org. Chem., 2011, 76, 9593. (d) Shaabani, A.;
Behnam, M.; Rezayan, A. H. Catal. Commun. 2009,10, 1074.
1
1
5. Mello, R.; Olmos, A.; Alcalde-Aragonés, A.; Díaz-Rodríguez, A.; González Núñez, M. E.; Asensio, G. Eur. J. Org. Chem., 2010,
6
200.
6. (a) Zhang, B.; Li, S.; Yue, S.; Cokoja, M.; Zhou, M.-D.; Shu-Liang, Z. K.; Fritz. E. J. Organomet. Chem. 2013, 744, 108; (b) Wang,
S.; Wang, L.; Djakovic, M.; Popovic, Z.; Wu, H.; Liu, Y. ACS Catalysis 2012, 2, 230.
1
1
1
2
7. Hallett, J. P.; Welton, T. Chem. Rev., 2011, 111, 3508.
8. (a) US. Patent application filed, serial no. 13/860,451. (b) Heidarizadeh, F.; Asareh, H. Asian J. Chem. 2009, 21, 949.
9. Ruff, F.; Fábián, A.; Farkas, Ö.; Kucsman, Á. Eur. J. Org. Chem. 2009, 2102.
0. Representative experimental procedure for the oxidation of diphenylsulfide to the corresponding sulfone (Table 2, 3e): A mixture of
1
8
diphenyl sulphide (1 mmol) and [pmim]IO
4
ionic liquid (prepared by the reaction of [pmim]BF
4
and NaIO
4
) (4 equiv.) was
o
3
vigorously stirred under air at 50 C for 4 hours (TLC). The reaction mixture was extracted with ethyl acetate (3 X 7 cm ) and the
extract was washed with brine and dried over Na
2
SO
4
. Evaporation of organic solvent left the crude product which was recrystalised
o
from ethanol to provide the corresponding sulfone as a white solid , mp 123 C; IR (KBr) νmax= 3080, 3066, 2781, 2459, 2330, 1969,
-
1 1
1
898, 1770, 1579, 1475, 1448, 1309, 1155 cm ; H NMR (500 MHz, CDCl
3
) δ 7.50 (t, J = 7.5 Hz, 4H), 7.56 (t, J = 7 Hz, 2H), 7.95 (d,
1
3
J = 7.5 Hz, 4H); C NMR (125 MHz, CDCl
3
) δ 127.8 (4C), 129.4 (4C), 133.3 (2C), 141.8 (2C).
This procedure was followed for all the reactions listed in Table 2 and Table 3. Although this procedure was described with a 1 mmol
scale, 10 mmol scale reactions also provided uniform results. All of these products listed in Table 2 are known except five (Table 2,
3
b, 3g, 3j, 3l and 3o). The all heterocyclic sulfones in Table 3 are new except one (Table 3, 4e). These known compounds were
1
13
21a
21b
21b
21c
21c
21d
21e
identified by comparison of their spectral data ( H NMR and C NMR) with those reported (3a, 3c, 3d, 3e, 3f, 3h, 3i,
2
1f
21g
21f
21i
21j
21j
21b
1
13
3
k, 3m, 3n, 3p, 3q, 3r, 4e, ). The new compounds were properly characterized by their IR, H NMR, C NMR, and
HRMS spectroscopic data which were provided below.
-
((Octadecylsulfonyl)methyl)benzene (Table 2, 3b). Colourless liquid; IR (neat) νmax= 2966, 2914, 1921, 1871, 1344, 1275, 1193 cm
1
1
;
H NMR (500 MHz, CDCl
3
) δ 0.87 (t, J = 6.5 Hz, 3H), 1.25-1.29 (m, 25 H), 1.34-1.37 (m, 2H), 2.80 (t, J = 8.0 Hz, 2H), 4.21 (s,
1
3
2
H), 7.40 (s, 5H); C NMR (125 MHz, CDCl ) δ 14.2, 21.9 (2C), 22.8, 29.2 (2C), 29.4 (2C), 29.5 (2C), 29.6 (2C), 29.7, 29.8, 32.1,
3

5
1
1
1.3, 59.6, 128.4, 129.1 (2C), 129.2 (2C), 130.7 (2C); Anal Calcd for C25
H
44
O
2
S: C, 73.47; H 10.85; Found: C, 73.44; H 11.01%.
o
-(4-Chlorophenylsulfonyl)-3,5-dimethylbenzene (Table 2, 3g). White solid; mp 137-139 C; IR (KBr) νmax
= 3084, 2955, 2916,
-1 1
908, 1764, 1607, 1578, 1472, 1391, 1321, 1151, 1084 cm ; H NMR (500 MHz, CDCl
3
) δ 2.43 (s, 3H), 7.26 (s, 2H), 7.54 (d, J = 8.0
1
3
Hz, 2H), 7.60 (s, 2H), 7.94 (d, J = 8.5 Hz, 2H); C NMR (125 MHz, CDCl
3
) δ 21.4 (2C), 125.3 (2C), 129.2 (2C), 129.7 (2C), 135.3
(2C), 139.6, 139.8, 140.6, 141.0; Anal Calcd for C14
H
13ClO
2
S: C, 59.89; H 4.67; Found: C, 60.02; H 4.51%.
o
1
-(4-Chlorophenylsulfonyl)-3-fluorobenzene (Table 2, 3j). White solid; mp 128-131 C; IR (KBr) νmax= 2966, 2938, 2846, 1581,
-
1 1
1
463, 1417, 1329, 1291cm ; H NMR (500 MHz, CDCl
3
) δ 7.28-7.30 (m, 1H), 7.48-7.53 (m, 3H), 7.62-7.64 (m, 1H), 7.72 (d, J = 8.0
) δ 115.15 (d, J = 23.7 Hz, 1C), 118.6 (d, J =21.2 Hz, 1C), 123.6 (d, J =
.7 Hz, 1C), 129.4 (2C), 129.9 (2C), 131.4 (d, J = 8.7 Hz, 1C), 139.6, 140.5, 143.5, 162.3 (d, J = 251.2 Hz, 1C); HRMS Calcd for
1
3
Hz, 1H), 7.88 (d, J = 8.5 Hz, 1H); C NMR (125 MHz, CDCl
3
3
+
C
12 8 2
H ClFO S [M+H] : 270.9996; Found: 270.9989.
o
2
-(2,6-Dimethylphenylsulfonyl)-1,3-dimethoxybenzene (Table 2, 3l). White solid; mp 153-155 C; IR (KBr) νmax
=
2972, 2941,
-1 1
2
837, 1584, 1474, 1429, 1310, 1254, 1155, 1107, 779 cm ; H NMR (500 MHz, CDCl ) δ 2.59 (s, 6H), 3.69 (s, 6H), 6.55 (d, J = 8.5
3
1
3
Hz, 2H), 7.04 (d, J = 7.5 Hz, 2H), 7.21 (t, J = 7.5 Hz, 1H), 7.38 (t, J = 8.5 Hz, 1H); C NMR (125 MHz, CDCl
2C), 105.3 (2C), 130.7 (2C), 131.3 (2C), 134.5 (2C), 139.1 (2C), 159.4 (2C); HRMS Calcd for C16
Found: 329.0821.
3
) δ 21.7 (2C), 56.4
+
(
H
18
O
4
S [M+Na] : 329.0823;
o
2
1
1
-(4-Bromophenylsulfonyl)-1-methyl-3-nitrobenzene (Table 2, 3o). White solid; mp 190-192 C; IR (KBr) νmax= 3091, 2951, 2879,
-1 1
933, 1568, 1535, 1475, 1389, 1358, 1313, 1153, 1066, 887 cm ; H NMR (500 MHz, CDCl
3
) δ 2.56 (s, 3H), 7.54 (d, J = 8.0 Hz,
1
3
H), 7.68-7.71 (m, 3H), 7.83 (d, J = 8.5 Hz, 2H), 8.17 (s, 1H); C NMR (125 MHz, CDCl
3
) δ 21.7, 125.4, 129.2, 130.0 (2C), 132.1
+
(2C), 132.5 (2C), 134.4, 135.1, 140.0, 144.5; HRMS Calcd for C13
H
10BrNO
4
S [M+H] : 355.9592; Found: 355.9581.
o
2
1
7
1
1
1
7
1
2
2
2
7
-(3,5-Dimethylphenylsulfonyl)pyridine (Table 3, 4a). White solid; mp 143-147 C; IR (KBr) νmax= 3053, 2953, 1607, 1574, 1454,
-1 1
3
323, 1271, 1165, 1149, 1120, 987 cm ; H NMR (500 MHz, CDCl ) δ
2.36 (s, 6H), 7.20 (s, 1H), 7.26-7.46 (m, 1H), 7.66 (s, 2H),
13
3
.90-7.93 (m, 1H), 8.19 (d, J = 8.0 Hz, 1H), 8.68 (d, J = 4.0 Hz, 1H); C NMR (125 MHz, CDCl ) δ 21.3 (2C), 122.3, 126.5, 126.9,
+
35.7, 138.2, 138.8, 138.3, 139.4, 150.6 (2C), 158.3; HRMS Calcd for C13
H
13NO
2
S [M+Na] : 270.0565; Found: 270.0566.
o
-(5-(Pyridin-3-ylsulfonyl)thiophen-2-yl)ethanone (Table 3, 4b). White solid; mp 149-150 C; IR (KBr) νmax= 2998, 1975, 1684,
-1 1
3
601, 1568, 1422, 1357, 1258, 1178 cm ; H NMR (500 MHz, CDCl ) δ 2.57 (s, 3H), 7.51-7.53 (m, 1H), 7.62 (d, J = 3.5 Hz, 1H),
1
3
3
.83 (d, J = 4.5 Hz, 1H), 7.95-7.98 (m, 1H), 8.20 (d, J = 8 Hz, 1H), 8.71 (d, J = 4.5 Hz, 1H); C NMR (125 MHz, CDCl ) δ 27.1,
+
22.2, 127.6, 131.2, 135.1, 138.5, 146.2, 150.7, 151.6, 158.2, 190.4; HRMS Calcd for C11
68.0098.
H
9
NO
3
S
2
[M+H] : 268.0102; Found:
o
-(3-(Trifluoromethyl)phenylsulfonyl)benzo[d]thiazole (Table 3, 4c). White solid; mp 135-136 C; IR (KBr) νmax= 2965, 2923,
-1 1
841, 1588, 1481, 1447, 1309, 1263, 1158, 1127cm ; H NMR (500 MHz, CDCl
3
) δ 7.32 (t, J = 8.0 Hz, 1H), 7.44 (t, J = 8.0 Hz, 1H),
13
.59 (t, J = 7.5 Hz, 1H), 7.71 (d, J = 8.0 Hz, 1H), 7.74 (d, J = 8.0 Hz, 1H), 7.91 (d, J = 8.0 Hz, 2H), 8.00 (s, 1H); C NMR (500 MHz,
CDCl
3
) δ 121.1, 122.5, 125.0, 126.5, 126.9, 127.0, 130.4, 131.4, 131.5, 131.8, 132.6, 135.9, 138.0, 153.8, 166.7; HRMS Calcd for
+
C
12
H
8
ClFO
2
S [M+H] : 270.9996; Found: 270.9989.
o
2
-(5-(Pyridin-2-ylsulfonyl)thiazol-2-ylthio)pyridine (Table 3, 4d). Light yellow solid; mp 128-131 C; IR (KBr) νmax= 2986, 2931,
-1
1
2
3
852, 1571, 1484, 1441, 1319, 1272, 1164, 1097 cm ; H NMR (500 MHz, CDCl ) δ 7.18-7.24 (m, 1H), 7.25-7.26 (m, 1H), 7.41 (d,
J = 8.0 Hz, 1H), 7.48-7.50 (m, 1H), 7.68-7.71 (m, 1H), 7.92-7.99 (m, 1H), 8.18 (t, J = 8.5 Hz, 1H), 8.33 (s, 1H), 8.65(s, 1H), 8.71 (s,
1
3
H); 13C NMR (125 MHz, CDCl ) δ 121.7, 122.4, 123.5, 127.4, 134.8, 137.5, 138.5, 148.2, 149.3, 150.6, 152.3, 158.6, 170.7; HRMS
+
calcd for C13
H
9
N
3
O
2
S
3
[M+Na] : 357.9755; Found: 357.9751.
2
1. (a) Traynelis, V. J.; Yoshikawa, Y. S.; Tarka, M.; Livingston, J. R. Jr. J. Org. Chem. 1973, 38, 3986; (b) Jereb, M. Green Chem.,
012, 14, 3047; (c) Rostami, A.; Akradi, J. Tetrahedron Lett. 2010, 51, 3501; (d) Istrati, D.; Popescu, A.; Mihaiescu, D.; Saramet, I.;
2
Balasu, M. C. Revue Roumaine de Chimie 2008, 53, 497; (e) Buehler, C. A.; Masters, J. E. J. Org. Chem. 1939, 4, 262; (f) Groves, L.
G.; Turner, E. E. J. Chem. Soc. 1929, 509; (g) Shen, C.; Yu, J. X.; Wenbo, P. Z. Green Chem. 2014, 16, 3007; (h) Burton, H.; Hu, P.
F. J. Chem. Soc. 1948, 601; (i) Wu, X.-S.; Chen, Y.; Li, M.-B.; Zhou, M.-G.; Tian, S.-K. J. Am. Chem.Soc. 2012, 134, 14694; (j) Zhu,
X.-Q.; Liang, H.; Zhu, Y.; Cheng, J.-P. J. Org. Chem. 2008, 73, 8403.

Supplementary Material
1
13
Supplementary material (Scanned copies of H and C NMR spectral data) associated with this article can be found, in the
online version, at http://