1-Arylsulfonyl-2-styrylsulfonylethenes - Source for a new class of bis heterocycles

Article abstract of DOI:10.1002/jhet.5570450604

(Chemical Equation Presented) New and novel sulfone linked bis heterocycles - bis pyrroles and pyrrolyl pyrazolines are prepared from 1-arylsulfonyl-2- styrylsulfonylethenes by 1,3-dipolar cycloaddition methodology.

Full text of DOI:10.1002/jhet.5570450604

Nov-Dec 2008
1579
1-Arylsulfonyl-2-styrylsulfonylethenes – Source for a New Class
of Bis Heterocycles
Venkatapuram Padmavathi,* Thunga Radhalakshmi, Gali Sudhakar Reddy and
Adivireddy Padmaja
Department of Chemistry, Sri Venkateswara University, Tirupati-517502, India
(Phone: +91-877-2249666-303: Fax: +91-877-2248499)
E-mail: vkpuram2001@yahoo.com
Received January 9, 2008
O
O
O
O
ArSO2
S
Ph ArSO2
S
Ph
O
O
S
ArSO2
Ph
N
N
H
N
H
N
H
N
H
1
3
5
Ar = Ph, 4-MePh, 4-ClPh
New and novel sulfone linked bis heterocycles – bis pyrroles and pyrrolyl pyrazolines are prepared from
1-arylsulfonyl-2-styrylsulfonylethenes by 1,3-dipolar cycloaddition methodology.
J. Heterocyclic Chem., 45, 1579 (2008).
INTRODUCTION
bis(heterocycles) having pyrrole with pyrazole unit by
1,3-dipolar cycloaddition of tosylmethyl isocyanide
(TosMIC) and diazomethane to activated olefins.
Heterocycles have gained immense importance
biologically and continue to be a major contributing
nucleus in organic chemistry. Among different
heterocyclic systems pyrroles and pyrazoles have gained
much attention due to their varied physiological
properties. Recently, pyrrole derivatives have emerged as
chemotherapeutic agents potentially useful for inhibiting
the activities of M. tuberculosis and other atypical
mycobacteria, including M. avium complex, an
opportunistic pathogen that greatly contributes to the
death of AIDS patients [1]. Porretta and co-workers [2]
have reported the antimicrobial activity of a pyrrole
derivative. Di Santo etal [3] ascribed appreciable
inhibiting action to pyrrolnitrin and some related
nitropyrroles. In fact, a variety of pyrazole derivatives
were synthesized as a new class of COX-1/COX-2
inhibitors. Although COX-2 inhibitors have anti-
inflammatory properties, their greatest effect appears to
be associated with pain relief and symptoms of
osteoarthritis. It was found that Celecoxib, a pyrazole
derivative had no effect on platelet aggregation and did
not reduce increased PG levels in cerebrospinal fluids [4].
Hence, it is considered worthwhile to prepare bis(hetero-
cycles) having both pyrrole and pyrazole units.
Substantial attention has been paid to developing efficient
methods for the synthesis of pyrroles which proceed
mainly via cycloaddition or cycloisomerisation of acyclic
precursors leading to 2,5-di or poly-substituted pyrroles
[5]. Tosyl methyl isocyanide (TosMIC) has also been
used as a reagent for the synthesis of pyrroles [6]. One of
the general methods to accomplish the synthesis of
pyrazolines is 1,3-dipolar cycloaddition of an ylide to an
alkene [7]. The present communication deals with the
RESULTS AND DISCUSSION
The synthetic scheme involves the reaction of 1-aryl-
sulfonyl-2-styrylsulfonylethenes (1) with TosMIC in the
presence of sodium hydride in a solvent mixture of ether
and DMSO (Scheme and Mechanism 1). When the
reaction is carried out with 1 mmol of 1 and 2 mmol of
TosMIC, a mixture of products is obtained in a 3:1 ratio,
which is separated by column chromatography (Table 1).
They are identified as 4-arylsulfonyl-3-(2'-phenyl-ethene-
sulfonyl)-1H-pyrrole (2 major) and 3-(4'-phenyl-1'H-
pyrrole-3'-sulfonyl)-4-phenyl-sulfonyl-1H-pyrrole (3 minor)
1
by their H NMR spectra. The compound 2a exhibited
two singlets at ꢀ 6.84 and 7.02 ppm, assigned to H-2 and
H-5 of the pyrrole ring. Two doublets are observed at ꢀ
Scheme 1
Method (3)
iii
O
O
O
O
ArSO2
+
S
Ph
ArSO2
S
2'
O
O
Ph
3' 4'
4
3
4
3
1'
S
i
2
5
2
2'
5
5'
ArSO2
Ph
1
1
1'
N
H
N
H
N
H
2
1
3
Method (2) ii
iv
O
O
O
O
HA
ArSO2
S
Ph
ArSO2
S
Ph
3'
4'
5'
4
3
HM
HX
v
2
5
2'
N
N
1
1'
N
H
N
H
N
H
N
H
4
5
i) 2TosMIC, NaH, Et2O + DMSO; ii) TosMIC, NaH, Et2O + DMSO ;
iii) 4TosMIC, NaH, Et2O + DMSO; iv) CH2N2 / Et2O / Et3N; v) Chloranil, Xylene
a) Ar = Ph; b) Ar = 4-MePh; c) Ar = 4-ClPh
synthesis
hitherto
unknown
sulfone
linked

1580
V. Padmavathi, T. Radhalakshmi, G. S. Reddy and A. Padmaja
Vol 45
formed could not be isolated. The IR spectra of 2 and 3
displayed absorption bands in the regions 1130-1145 and
1322-1340 (SO2) and 3164-3182 cm-1 (NH). Compound 2
showed an additional band at 1628-1633 cm-1 (C=C)
(Table 2).
Mechanism 1
O
O
O
O
_
ArSO2
Tos
S
_
S
Ph
ArSO2
Ph +
Tos CH-N=C
C
1
N
The olefin group in 2 was used to develop a different
heterocyclic ring, pyrazole. Treatment of
diazomethane at -20 ºC to -15 ºC gave a solid, which
was identified as 3'-(4-(arylsulfonyl)-1H-pyrrol-3-yl-
sulfonyl)-4',5'-dihydro-4'-aryl-1'H-pyrazole
2 with
O
O
O
O
_
ArSO2
Tos
S
ArSO2
Tos
S
+
~ H
Ph
Ph
Ph
_
N
N
(4)
by
spectral parameters (Mechanism 2). The 1H NMR
spectrum of 4a displayed an AMX splitting pattern for
pyrazoline ring protons at ꢀ 4.49 (HA), 3. 86 (HM) and
3.45 ppm (HX) respectively, in addition to the signals of
the pyrrole ring protons. The observed coupling
constant values JAM = 11.9, JAX = 5.5 and JMX = 10.5 Hz
indicate that HA, HM are cis, HA, HX are trans and HM,
HX are geminal. Compound 4 on oxidation with
chloranil in xylene [8] gave the corresponding
O
O
O
O
H
+
ArSO2
S
ArSO2
S
~ H
Ph
N
H
N
2
6.75 and 7.45 ppm corresponding to the olefinic protons,
in addition to the signals of the aromatic protons.
Compound 3a presented a sharp singlet at ꢀ 6.78 ppm
corresponding to H-2,2' and two singlets at ꢀ 7.03 and
6.98 ppm due to H-5 and H-5'. Repetition of this reaction
with a twofold excess of TosMIC resulted in 3 only. In 2
and 3 there is a possibility of a mixture of diastereomeric
adducts. However, we could isolate only one pure
compound. A small amount of the other isomers, if any,
Mechanism 2
O
O
H
O
O
O
O
Ph
Ph
ArSO2
S
ArSO2
S
ArSO2
S
Ph
N
N
N
+
N
N
H
N
N
H
N
H
N
H
_
H2C
4
2
Table 1
Physical and Analytical Data of Compounds 2-5
Compound
Mp
(°C)
Ar
Yield
%
Molecular Formula
Analysis %
Calcd. /Found
C
H
N
2a
2b
2c
3a
3b
241-243
233-235
261-263
252-254
238-240
C6H5
58
56
60
C18H15NO4S2
C19H17NO4S2
C18H14ClNO4S2
C20H16N2O4S2
C21H18N2O4S2
57.89
58.01
58.90
58.99
53.00
52.94
58.24
58.32
59.14
59.20
4.05
4.10
4.42
4.45
3.46
3.44
3.75
3.82
3.61
3.67
3.43
3.39
p-MeC6H4
p-ClC6H4
C6H5
15
68a 71b
3.91
3.95
4.25
4.28
6.79
6.84
6.57
6.62
p- MeC6H4
18
72a
74b
20
69a
73b
66
3c
280-282
p-ClC6H4
C20H15ClN2O4S2
53.75
53.70
3.38
3.40
6.27
6.25
4a
4b
4c
5a
5b
5c
249-251
238-240
273-275
284-286
268-270
296-298
C6H5
C19H17N3O4S2
C20H19N3O4S2
C19H16ClN3O4S2
C19H15N3O4S2
C20H17N3O4S2
C19H14ClN3O4S2
54.92
54.88
55.93
56.00
50.72
50.66
55.19
55.27
56.19
56.24
50.95
51.04
4.12
4.08
4.46
4.50
10.11
10.17
9.78
p- MeC6H4
p-ClC6H4
C6H5
70
65
77
79
80
9.85
3.58
3.60
3.66
3.63
4.01
4.00
3.15
3.17
9.34
9.40
10.16
10.25
9.83
9.80
9.38
9.42
p- MeC6H4
p-ClC6H4
a
yield in method - 2;
b
yield in method – 3.

Nov-Dec 2008
1-Arylsulfonyl-2-styrylsulfonylethenes – Source for a New Class of Bis Heterocycles
1581
Table 2
IR Data of Compounds 2-5
Compound
IR (cm-1)
SO2
C=C
C=N
NH
2a
2b
2c
3a
3b
3c
4a
4b
4c
5a
5b
5c
1138
1145
1130
1144
1136
1142
1138
1146
1130
1142
1134
1145
1335
1332
1340
1320
1325
1327
1334
1330
1335
1330
1328
1336
1632
1628
1633
1630
1627
1634
1626
1621
1624
1630
1625
1631
-
-
-
-
-
3171
3182
3164
3169
3175
3166
3280
3285
3291
3270
3275
3288
-
1614
1609
1598
1613
1611
1609
Table 3
1H and 13C NMR Data of Compounds 2-5
1H NMR (ꢀ, ppm)
Compound
13C NMR (ꢀ, ppm)
6.75 (d, 1H, C1'-H, J = 18.0 Hz), 6.87 (s, 1H, C2-H), 7.02 (s, 106.6 (C-3), 110.3 (C-4), 120.2 (C-1'), 122.8 (C-2),
1H, C5-H), 7.45 (d, 1H, C2'-H, J = 18.0 Hz), 7.27-7.55 (m, 124.7 (C-5), 137.2 (C-2'), 129.8, 131.2, 131.7, 132.3,
2a
10H, Ar and Ar'-H), 8.79 (bs, 1H, NH)
132.9, 133.4, 133.9 (aromatic carbons)
2.32 (s, 3H, Ar-CH3), 6.78 (d, 1H, C1'-H, J = 17.8 Hz), 6.86 (s, 21.4 (Ar-CH3), 107.2 (C-3), 110.9 (C-4), 119.8 (C-1'),
1H, C2-H), 7.04 (s, 1H, C5-H), 7.48 (d, 1H, C2'-H, J = 17.8 122.1 (C-2), 123.8 (C-5), 138.0 (C-2'), 129.2, 130.4,
2b
Hz), 7.22-7.49 (m, 9H, Ar and Ar'-H), 8.74 (bs, 1H, NH)
131.6, 132.7, 133.8, 134.2, 135.3 (aromatic carbons)
6.76 (d, 1H, C1'-H, J = 18.1 Hz), 6.84 (s, 1H, C2-H), 7.07 (s, 107.9 (C-3), 111.4 (C-4), 120.9 (C-1'), 122.4 (C-2),
1H, C5-H), 7.46 (d, 1H, C2'-H, J = 18.1 Hz), 7.31-7.73 (m, 9H, 124.8 (C-5), 137.6 (C-2'), 128.3, 129.6, 130.3, 131.9,
2c
3a
3b
Ar and Ar'-H), 8.77 (bs, 1H, NH)
132.6, 133.4, 135.7, 137.2 (aromatic carbons)
6.78 (s, 2H, C2-H & C2'-H), 6.98 (s, 1H, C5'-H), 7.03 (s, 1H, 104.5 (C-4'), 108.6 (C-3 and 3'), 110.3 (C-4), 114.5 (C-2
C5-H), 7.24-7.58 (m, 10H, Ar and Ar'-H), 8.75 (bs, 2H, NH)
and 2'), 117.7 (C-5'), 124.2 (C-5), 128.2, 129.5, 130.6,
131.3, 132.9, 133.7, 134.6, 135.2 (aromatic carbons)
2.28 (s, 3H, Ar-CH3), 6.74 (s, 2H, C2-H & C2'-H), 6.96 (s, 1H, 22.6 (Ar-CH3), 103.9 (C-4'), 107.9 (C-3 and 3'), 109.1
C5'-H), 7.01 (s, 1H, C5-H), 7.20-7.51 (m, 9H, Ar and Ar'-H), (C-4), 113.7 (C-2 and 2'), 116.5 (C-5'), 124.5 (C-5),
8.72 (bs, 2H, NH)
128.6, 129.3, 130.2, 131.6, 132.2, 133.4, 133.9, 134.7
(aromatic carbons)
6.76 (s, 2H, C2-H & C2'-H), 6.94 (s, 1H, C5'-H), 7.05 (s, 1H, 104.9 (C-4'), 108.4 (C-3 and 3'), 110.9 (C-4), 114.2 (C-2
3c
4a
C5-H), 7.29-7.67 (m, 9H, Ar and Ar'-H), 8.78 (bs, 2H, NH)
and 2'), 117.1 (C-5'), 123.6 (C-5), 129.4, 130.8, 131.7,
132.6, 133.2, 135.6, 138.1 (aromatic carbons)
3.45 (dd, 1H, HX), 3.86 (dd, 1H, HM, JMX = 10.5 Hz), 4.49 (dd, 46.4 (C-4'), 56.8 (C-5'), 111.7 (C-3), 113.7 (C-4), 125.2
1H, HA, JAM = 11.9 Hz, JAX = 5.5 Hz), 6.85 (s, 1H, C2-H), 7.04 (C-5), 126.1 (C-2), 151.2 (C-3'), 128.6, 129.2, 130.2,
(s, 1H, C5-H), 7.23-7.53 (m, 10H, Ar and Ar'-H), 8.74 (bs, 1H, 131.2, 132.7, 133.4, 134.6, 136.3 (aromatic carbons)
NH), 10.49 (bs, 1H, NH)
2.30 (s, 3H, Ar-CH3), 3.47 (dd, 1H, HX), 3.84 (dd, 1H, HM, JMX 22.8 (Ar-CH3), 45.9 (C-4'), 57.0 (C-5'), 111.4 (C-3),
= 10.3 Hz), 4.47 (dd, 1H, HA, JAM = 11.8 Hz, JAX = 5.4 Hz), 113.7 (C-4), 125.7 (C-5), 126.3 (C-2), 151.4 (C-3'),
6.83 (s, 1H, C2-H), 7.01 (s, 1H, C5-H), 7.25-7.59 (m, 9H, Ar 128.7, 129.4, 130.9, 131.2, 132.7, 133.2, 134.8, 135.6
4b
4c
5a
5b
5c
and Ar'-H), 8.76 (bs, 1H, NH), 10.42 (bs, 1H, NH)
(aromatic carbons)
3.44 (dd, 1H, HX), 3.82 (dd, 1H, HM, JMX = 10.1 Hz), 4.45 (dd, 47.1 (C-4'), 57.5 (C-5'), 112.6 (C-3), 114.5 (C-4), 124.2
1H, HA, JAM = 11.6 Hz, JAX = 5.3 Hz), 6.812 (s, 1H, C2-H), (C-5), 127.1 (C-2), 151.2 (C-3'), 129.8, 130.6, 131.1,
7.03 (s, 1H, C5-H), 7.30-7.65 (m, 9H, Ar and Ar'-H), 8.74 (bs, 131.9, 132.4, 133.8, 134.5, 137.9 (aromatic carbons)
1H, NH), 10.45 (bs, 1H, NH)
6.32 (bs, 1H, NH), 6.72 (s, 1H, C2-H), 6.91 (s, 1H, C5'-H), 6.96 112.1 (C-3), 116.3 (C-4), 125.6 (C-5), 127.4 (C-2),
(s, 1H, C5-H), 7.26-7.63 (m, 10H, Ar and Ar'-H), 8.92 (bs, 1H, 134.3 (C-5'), 138.6 (C-4'), 156.4 (C-3'), 128.2, 129.2,
NH)
130.6, 131.4, 132.0, 133.2, 134.5, 135.7 (aromatic
carbons)
2.26 (s, 3H, Ar-CH3), 6.34 (bs, 1H, NH), 6.75 (s, 1H, C2-H), 21.9 (Ar-CH3), 111.9 (C-3), 115.9 (C-4), 124.6 (C-5),
6.93 (s, 1H, C5'-H), 6.98 (s, 1H, C5-H), 7.19-7.51 (m, 9H, Ar 127.1 (C-2), 134.6 (C-5'), 139.2 (C-4'), 153.8 (C-3'),
and Ar'-H), 8.96 (bs, 1H, NH)
128.2, 129.2, 130.6, 131.4, 132.0, 133.2, 134.5, 135.7
(aromatic carbons)
6.37 (bs, 1H, NH), 6.71 (s, 1H, C2-H), 6.95 (s, 1H, C5'-H), 6.95 112.4 (C-3), 116.1 (C-4), 125.7 (C-5), 127.7 (C-2),
(s, 1H, C5-H), 7.28-7.69 (m, 9H, Ar and Ar'-H), 8.94 (bs, 1H, 133.8 (C-5'), 139.5 (C-4'), 156.5 (C-3'), 129.4, 130.3,
NH)
131.4, 132.1, 132.9, 134.7, 135.2, 138.5 (aromatic
carbons)

1582
V. Padmavathi, T. Radhalakshmi, G. S. Reddy and A. Padmaja
Vol 45
solid was purified by column chromatography (hexane-ethyl
acetate; 1:4).
aromatized product, 3'-(4-(arylsulfonyl)-1H-pyrrol-3-
ylsulfonyl)-4'-aryl-1'H-pyrazole (5). The disappearance
of the AMX splitting pattern and the appearance of
three signals at 6.72, 6.91 and 6.96 ppm due to H-2, H-
5' and H-5 in the 1H NMR spectrum of 5a confirms their
formation. The structures of 2-5 are further confirmed
by 13C NMR spectra (Table 3).
Method-3. A mixture of TosMIC (20 mmoles) and 1-aryl-
sulfonyl-2-styrylsulfonylethene (1) (5 mmoles) in Et2O-DMSO
(2:1) was added dropwise to a stirred suspension of sodium
hydride (100 mg) in Et2O (20 mL) at room temperature and
stirring was continued for about 5 hours. The reaction mixture
was diluted with water and extracted with ether. The ethereal
layer was dried over anhydrous sodium sulfate and the solvent
was removed in vacuo. The resulting solid was purified by
column chromatography (hexane-ethyl acetate; 1:4).
3'-(4-(Arylsulfonyl)-1H-pyrrol-3-ylsulfonyl)-4',5'-dihydro-
4'-phenyl-1'H-pyrazole (4): General Procedure. To a cooled
solution of 2 (5 mmoles) in dichloromethane (20 mL), an
ethereal solution of diazomethane (40 mL, 0.4 M) and
triethylamine (0.12 g) were added. The reaction mixture was
kept at -20 ºC to -15 ºC for 40-48 hours. The solvent was
removed under reduced pressure and the resulting solid was
recrystallized from 2-propanol.
3'-(4-(Arylsulfonyl)-1H-pyrrol-3-ylsulfonyl)-4'-phenyl-1'H-
pyrazole (5): General Procedure. A solution of 4 (1 mmole)
and chloranil (1 mmole) in xylene (10 mL) was refluxed for 24-
32 hours. The reaction mixture was treated with a 5% NaOH
solution. The organic layer was separated and repeatedly washed
with water, dried over anhydrous sodium sulfate and the solvent
was removed on a rotary evaporator. The solid obtained was
recrystallized from 2-propanol.
CONCLUSION
New and novel sulfone linked bis (pyrroles) and
pyrrolyl pyrazolines are prepared from a suitable synthetic
intermediate, 1-arylsulfonyl-2-styrylsulfonylethene.
EXPERIMENTAL
Melting points were determined in open capillaries on a Mel-
Temp apparatus and are uncorrected. The purity of the
compounds was checked by TLC (silica gel H, BDH, ethyl
acetate/hexane, 1:3). The IR spectra were recorded on a Thermo
Nicolet IR 200 FT-IR spectrometer as KBr pellets and the
absorptions are given in cm-1. The 1H NMR spectra were
recorded in CDCl3/DMSO-d6 on a Varian EM-360 spectrometer
(300 MHz). The 13C NMR spectra were recorded in
CDCl3/DMSO-d6 on a Varian VXR spectrometer operating at
75.5 MHz. All chemical shifts are reported in ꢀ (ppm) using
TMS as an internal standard. The microanalyses were performed
on a Perkin-Elmer 240C elemental analyzer. The starting
compound 1-arylsulfonyl-2-styrylsulfonylethene (1) was
prepared by the literature procedure [9].
4-Arylsulfonyl-3-(2'-phenylethenesulfonyl)-1H-pyrrole (2)
and 3-(4'-phenyl-1'H-pyrrole-3'-sulfonyl)-4-phenylsulfonyl-
1H-pyrrole (3): General Procedure. A mixture of TosMIC (10
mmoles) and 1-arylsulfonyl-2-styrylsulfonylethene (1) (5
mmoles) in Et2O-DMSO (2:1) was added dropwise to a stirred
suspension of sodium hydride (50 mg) in Et2O (10 mL) at room
temperature and stirring was continued for about 5 hours. The
reaction mixture was diluted with water and extracted with
ether. The ethereal fraction was dried over anhydrous sodium
sulfate. The solvent was removed in vacuo. The resulting
mixture was separated by column chromatography (hexane-ethyl
acetate; 1:4) and identified as. 3-arylsulfonyl-4-(2'-aryl-ethene-
sulfonyl)-1H-pyrrole (2, major) and 3-(4-(arylsulfonyl)-1H-
pyrrole-3-ylsulfonyl)-4'-aryl-1'H-pyrrole (3, minor).
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3-(4'-Phenyl-1'H-pyrrole-3'-sulfonyl)-4-phenylsulfonyl-1H-
pyrrole (3): General Procedure. Method-2. Compound 3 was
also obtained by adding an equimolar (5 mmoles) mixture of 4-
arylsulfonyl-3-(2'-phenylethenesulfonyl)-1H-pyrrole (2) and
TosMIC in Et2O-DMSO (2:1) was added dropwise to a stirred
suspension of sodium hydride (25 mg) in Et2O (6 mL) at room
temperature and stirring was continued for about 5 hours. The
reaction mixture was diluted with water and extracted with
ether. The ethereal layer was dried over anhydrous sodium
sulfate. The solvent was removed under vacuum. The resulting
[7] Padmavathi, V.; Reddy, K. V.; Padmaja, A.; Reddy, D. B.
Phosphorus, Sulfur and Silicon 2003, 178, 171.
[8a] Padmavathi, V.; Sarma, M. R.; Padmaja, A.; Reddy, D. B. J.
Heterocyclic Chem. 2003, 40, 933; [8b] Padmavathi, V.; Sumathi, R. P.;
Reddy, K. V.; Reddy, A. S.; Reddy, D. B. Synth. Commum. 2000, 30,
4007.
[9] Reddy, D. B.; Babu, N. C.; Reddy K. V.; Padmavathi, V.
Indian. J. Chem. 2001, 40B, 416.