Double Michael addition reactions to tetrakis sulfonyl activated olefins

Article abstract of DOI:10.1002/jhet.5570420212

A new class of bis Michael adducts are prepared from 1,3-bis-[2-(2- arylethenesulfonyl)-vinyl]-benzenes and 1,4-bis-[2-(2-arylethenesulfonyl)-vinyl] -benzenes by double Michael addition reaction with active methylene compounds.

Full text of DOI:10.1002/jhet.5570420212

March 2005
255
Double Michael Addition Reactions to
Tetrakis Sulfonyl Activated Olefins
Venkatapuram Padmavathi,* Dandu Rangayapalle Chinna Venkata Subbaiah and
Boggu Jagan Mohan Reddy
Department of Chemistry, Sri Venkateswara University, Tirupati 517 502, India
Received August 30, 2004
A new class of bis Michael adducts are prepared from 1,3-bis-[2-(2-arylethenesulfonyl)-vinyl]-benzenes
and 1,4-bis-[2-(2-arylethenesulfonyl)-vinyl]-benzenes by double Michael addition reaction with active
methylene compounds.
J. Heterocyclic Chem., 42, 255 (2005).
The carbon-carbon bond forming reactions are impor-
tant in achieving the desired molecular architecture. In
fact, the development of efficient and expedient method-
ologies for the synthesis of activated alkenes remains a
worthwhile task, which would serve as building blocks for
various carbocyclic and heterocyclic systems. Thus the
improvement and design of a new reaction system is a fun-
damental approach for any synthetic organic chemist. Over
the years, our research group has been actively involved in
this area. In recent past we have reported an unusually sim-
ple approach for the synthesis of E, Z-bis (styryl) sulfones
[1-2] and mono and bis unsaturated oxosulfones and bis
sulfones [3-4]. In continuation of our interest in activated
olefins, herein we report a new class of unsaturated sul-
fones, 1,3- and 1,4-bis-[(arylethenesulfonyl)-vinyl]-ben-
zenes 1 and 2 which have been used as Michael acceptors
in double Michael addition.
presence of benzylamine in acetic acid resulted in 1,3- and
1,4-bis-[(arylethenesulfonyl)-vinyl]-benzenes 1 and 2. The
IR spectra of 1 and 2 showed absorption bands in the
-1
regions 1305-1315, 1135-1150 (SO ) and 1620-1635 cm
2
(C=C). The presence of doublets at δ 7.75-7.81 (H ), 7.54-
D
7.58 (H ), 7.01-7.06 (H ) and 6.60-6.64 (H ) with cou-
A
C
B
pling constants: J = 10.5-10.8, J = 15.3-15.8 Hz in
AB
CD
1
their H NMR spectra indicated that H , H and H , H
A
B
C
D
are cis and trans oriented, respectively. These compounds
have been utilized as Michael acceptors in double Michael
addition reaction with different nucleophiles viz., dimethyl
malonate, ethyl cyanoacetate and malononitrile. In recent
past we have been actively engaged in the double Michael
addition of active methylene compounds to bis unsaturated
systems [5-8]. When the reaction has been carried out in
the presence of piperidine [9], sulfinic acid [10], phospho-
rus trichloride [11] afforded open chain adducts while
cyclic products have been obtained in the presence of
sodium methoxide or sodium hydroxide [12]. These cyclic
The Knoevenagel reaction of 2-arylethenesulfonylacetic
acid [1] with 1,3- and 1,4-benzenedicarboxaldehyde in the

256
V. Padmavathi, D. R. C. Venkata Subbaiah and B. Jagan Mohan Reddy
Vol. 42
adducts have been used to prepare a variety of spiro hete-
rocycles [13-15]. In continuation of our ongoing program
to develop some more interesting heterocycles, we thought
of extending the double Michael addition to newly pre-
pared tetrakis unsaturated sulfones.
amount of the other isomers, if any, formed could not be
isolated by this process. The IR spectra of compounds 3-
8 displayed absorption bands in the region 1305-1315 and
-1
1135-1150 cm (SO ). The compounds 3-6 showed bands
2
-1
at 1710-1730 cm (CO R). Apart from this, compounds 5-
8 exhibited bands in the region 2240-2250 cm (CN). The
2
-1
The reaction of 1,3- and 1,4-bis-[(arylethenesulfonyl)-
vinyl]-benzenes 1 and 2 with active methylene compounds
such as dimethyl malonate, ethyl cyanoacetate and mal-
ononitrile in the presence of Triton-B in THF resulted in
methine and methylene protons of these compounds (3-8)
1
in H NMR spectra showed three doublet of doublets thus
exhibiting an AMX splitting pattern. The doublet of dou-
blets observed at δ 4.28-4.34, 3.92-3.97 and 2.91-2.96 are
assigned to H , H and H , respectively. The J values
'
the formation of dimethyl 3,3-1,3- and 1,4-phenylene bis-
'
thiopyrandicarboxylate dioxides 3 and 4, ethyl 3,3 -1,3-
A
M
X
indicated that H , H are trans and H , H are cis ori-
and 1,4-phenylene bis-cyanothiopyrancarboxylate diox-
ides 5 and 6, 3,3 -1,3- and 1,4-phenylene bis-thiopyran-
A
M
A
X
'
ented while H , H are geminal. Apart from this 3 and 4
M
X
displayed two sharp signals in the regions δ 3.54-3.57 and
3.62-3.67 due to equatorial and axial carbomethoxy
groups. The downfield absorption may be assigned to axial
carbomethoxy group while the upfield shift to an equator-
dicarbonitrile dioxides 7 and 8 (Scheme). In compounds 3-
8 there are stereo centers and as a result a mixture of
diastereomeric bis-adducts could be formed. However we
could isolate only one pure compound when the reaction
mixture was passed through a column of silica gel. A small
13
ial one [5,7,16]. The C NMR spectra of 3-8 showed sig-
Table 1
'
'
Physical data of compounds dimethyl 3,3-1,3- and 1,4-phenylene bis-thiopyran-dicarboxylate dioxides 3 and 4, ethyl 3,3-1,3- and 1,4-
'
phenylene bis-cyanothiopyran-carboxylate dioxides 5 and 6, 3,3-1,3- and 1,4-phenylene bis-thiopyran-dicarbonitrile dioxides 7 and 8.
Compd.
No.
Ar
m.p.
(°C)
Yield
(%)
Mol. Formula
(Mol. Wt)
Calcd. (Found) %
H
C
N
3a
3b
3c
4a
4b
4c
5a
5b
5c
6a
6b
6c
7a
7b
7c
8a
8b
8c
Ph
158-160
163-165
202-204
169-171
201-203
222-224
153-155
168-170
196-198
161-163
203-205
218-220
165-167
172-174
209-211
169-171
205-207
231-233
68
73
77
71
65
76
66
69
73
71
76
78
63
68
64
70
69
72
C
C
H
O
S
S
59.49
(59.52)
60.46
(60.36)
54.34
(54.40)
59.49
(59.41)
60.46
(60.53)
54.34
(54.46)
62.77
(62.83)
63.67
(63.61)
57.07
(57.16)
62.77
(62.84)
63.67
(63.54)
57.07
(57.13)
64.63
(64.55)
65.57
(65.62)
57.92
(57.85)
64.63
(64.57)
65.57
5.27
(5.30)
5.61
(5.65)
4.56
(4.54)
5.27
(5.22)
5.61
(5.64)
4.56
(4.52)
5.27
(5.29)
5.62
(5.67)
4.52
(4.47)
5.27
(5.23)
5.62
(5.54)
4.52
(4.50)
4.41
(4.45)
4.86
(4.92)
3.65
(3.58)
4.41
(4.34)
4.86
36 38 12
2
2
(726.81)
--
--
4-Me.Ph
4-Cl.Ph
Ph
H O
38 42 12
(754.86)
H
(795.70)
H
(726.81)
H O
(754.86)
H
C
C
Cl O
S
--
--
--
--
36 36
2
12
2
C
C
O
S
S
36 38 12
2
4-Me.Ph
4-Cl.Ph
Ph
38 42 12
2
Cl O S
36 36
2 12
2
(795.70)
N O S
C
H
4.07
(4.00)
3.91
(3.99)
3.70
(3.81)
4.07
(4.12)
3.91
(3.98)
3.70
(3.78)
9.42
(9.39)
9.00
(9.09)
8.44
36 36
2
8
2
2
(688.81)
C H N O S
38 40
4-Me.Ph
4-Cl.Ph
Ph
2 8
(716.86)
H Cl N O S
C
C
C
C
36 34
2
2
8
2
2
2
2
(757.70)
N O S
C
C
H
36 36
2
8
2
2
(688.81)
N O S
4-Me.Ph
4-Cl.Ph
Ph
H
38 40
2 8
(716.86)
Cl N O S
H
36 34
2 2 8
(757.70)
N O S
C
C
H
32 26
4
4
2
2
(594.71)
N O S
4-Me.Ph
4-Cl.Ph
Ph
H
34 30
4 4
(622.76)
Cl N O S
H
32 24
2 4 4
(663.59)
N O S
(8.53)
9.42
(9.37)
9.00
(8.94)
8.44
C
C
H
32 26
4
4
2
2
(594.71)
N O S
4-Me.Ph
4-Cl.Ph
H
34 30
4 4
(622.76)
Cl N O S
(65.65)
57.92
(4.94)
3.65
H
32 24
2 4 4
(663.59)
(57.99)
(3.58)
(8.50)

March 2005
Double Michael Addition Reactions to Tetrakis Sulfonyl Activated Olefins
257
Table 2
Spectroscopic Data of Compounds 1-8
1
13
Compd.
No
H NMR
δ, ppm
C NMR
δ, ppm
1a
1b
6.64 (d, 2H, H , J=10.6 Hz), 7.03 (d, 2H, H , J=15.5 Hz), 7.14-7.30 (m,
125.6 (CH-SO ), 145.7 (CH-Ar)
2
B
C
14H, Ar-H), 7.57 (d, 2H, H , J=10.6 Hz), 7.78 (2H, H , J=15.5 Hz)
A
D
2.36 (s, 6H, CH ), 6.61 (d, 2H, H , J=10.8 Hz), 7.02 (d, 2H, H ,
124.8 (CH-SO ), 143.7 (CH-Ar)
2
3
B
C
J=15.6 Hz), 7.04-7.34 (m, 12H, Ar-H), 7.56 (d, 2H, H ,
A
J=10.8 Hz), 7.79 (2H, H , J=15.6 Hz)
D
1c
2a
2b
6.63 (d, 2H, H , J=10.5 Hz), 7.05 (d, 2H, H , J=15.4 Hz), 7.16-7.34 (m,
126.7 (CH-SO ), 142.8 (CH-Ar)
2
B
C
12H, Ar-H), 7.56 (2H, H , J=10.5 Hz), 7.81 (d, 2H, H , J=15.4 Hz)
A
D
6.63 (d, 2H, H , J=10.8 Hz), 7.01 (d, 2H, H , J=15.8 Hz), 7.16-7.33 (m,
124.6 (CH-SO ), 144.7 (CH-Ar)
2
B
C
14H, Ar-H), 7.56 (2H, H , J=10.8 Hz), 7.80 (d, 2H, H , J=15.6 Hz)
A
D
2.34 (s, 6H, CH ), 6.64 (d, 2H, H , J=10.6 Hz), 7.01-7.25 (m, 12H,
125.9 (CH-SO ), 145.3 (CH-Ar)
2
3
B
Ar-H), 7.06 (d, 2H, H , J=15.3 Hz), 7.58 (2H, H , J=10.6 Hz),
C
A
7.75 (d, 2H, H , J=15.3 Hz)
D
2c
3a
6.60 (d, 2H, H , J=10.7 Hz), 7.04 (d, 2H, H , J=15.4 Hz), 7.20-7.28 (m,
126.6 (CH-SO ), 144.3 (CH-Ar)
2
B
C
12H, Ar-H), 7.54 (d, 2H, H , J=10.7 Hz), 7.79 (2H, H , J=15.4 Hz)
A
D
2.94 (dd, 4H, H , J = 5.3, J = 15.7 Hz), 3.56 (s, 6H, eq-OCH ),
27.9 (C-3) 28.2 (C-5), 50.7 & 52.8 (OCH ), 56.0 (C-2 &
X
AX
MX
3
3
3.67 (s, 6H, ax-OCH ), 3.93 (dd, 4H, H , J = 10.5 Hz), 4.31 (dd,
C-6), 68.0 (C-4), 176.0 (C=O)
3
M
AM
4H, H ), 6.95-7.18 (m, 14H, Ar-H)
A
3b
3c
4a
4b
4c
5a
5b
5c
6a
6b
6c
2.36 (s, 6H, CH ), 2.91 (dd, 4H, H , J = 5.2, J = 15.9 Hz), 3.54
20.9 (CH ), 28.5 (C-3) 28.8 (C-5), 50.2 & 52.3 (OCH ), 56.4
(C-2 & C-6), 67.2 (C-4), 174.8 (C=O)
3
X
AX
MX
3
3
(s, 6H, eq-OCH ), 3.63 (s, 6H, ax-OCH ), 3.94 (dd, 4H, H , J =
3
3
M
AM
10.7 Hz), 4.33 (dd, 4H, H ), 6.95-7.12 (m, 12H, Ar-H)
A
2.91 (dd, 4H, H , J = 5.5, J = 15.7 Hz), 3.57 (s, 6H, eq-OCH ),
28.4 (C-3) 29.6 (C-5), 50.5 & 53.2 (OCH ), 56.3 (C-2 &
X
AX
MX
3
3
3.62 (s, 6H, ax-OCH ), 3.96 (dd, 4H, H , J = 10.4 Hz), 4.29 (dd,
C-6), 68.6 (C-4), 176.2 (C=O)
3
M
AM
4H, H ), 6.96-7.18 (m, 12H, Ar-H)
A
2.95 (dd, 4H, H , J = 5.2, J = 15.8 Hz), 3.57 (s, 6H, eq-OCH ),
28.3 (C-3 & C-5), 49.9 & 51.7 (OCH ), 56.4 (C-2 & C-6),
X
AX
MX
3
3
3.64 (s, 6H, ax-OCH ), 3.92 (dd, 4H, H , J = 10.7 Hz), 4.30 (dd,
66.2 (C-4), 175.8 (C=O)
3
M
AM
4H, H ), 7.08-7.19 (m, 14H, Ar-H)
A
2.35 (s, 6H, CH ), 2.94 (dd, 4H, H , J = 5.5, J = 15.8 Hz), 3.55
20.5 (CH ), 27.9 (C-3 & C-5), 49.6 & 50.8 (OCH ), 55.9 (C-2
3
X
AX
MX
3
3
(s, 6H, eq-OCH ), 3.64 (s, 6H, ax-OCH ), 3.93 (dd, 4H, H , J =
& C-6), 66.7 (C-4), 177.3 (C=O)
3
3
M
AM
10.5 Hz), 4.28 (dd, 4H, H ), 6.97-7.13 (m, 12H, Ar-H)
A
2.93 (dd, 4H, H , J = 5.3, J = 15.9 Hz), 3.56 (s, 3H, eq-OCH ),
28.1 (C-3 & C-5), 50.2 & 51.9 (OCH ), 55.9 (C-2 & C-6),
X
AX
MX
3
3
3.66 (s, 3H, ax-OCH ), 3.94 (dd, 4H, H , J = 10.6 Hz), 4.28 (dd,
67.2 (C-4), 174.9 (C=O)
3
M
AM
4H, H ), 7.05-7.19 (m, 12H, Ar-H)
A
1.32 (t, 6H, OCH2CH ), 2.92 (dd, 4H, H , J = 5.4, J = 15.8 Hz),
13.6 (OCH CH ), 28.0 (C-5), 28.3 (C-3), 55.5 (C-2 & C-6), 58.3
2 3
3
X
AX
MX
3.93 (dd, 4H, H , J = 10.4 Hz), 4.12 (q, 4H, OCH CH ), 4.30 (dd,
(C-4), 59.3 (OCH CH ), 119.2 (CN), 176.0 (C=O)
M
AM
2
3
2 3
4H, H ), 6.93-7.19 (m, 14H, Ar-H)
A
1.30 (t, 6H, OCH CH ), 2.37 (s, 6H, CH ), 2.96 (dd, 4H, H , J = 5.5,
13.7 (OCH CH ), 20.6 (CH ), 27.5 (C-5), 29.2 (C-3), 54.9 (C-2
2 3 3
2
3
3
X
AX
J
= 15.8 Hz), 3.93 (dd, 4H, H , J = 10.7 Hz), 4.11 (q,
& C-6), 57.4 (C-4), 58.9 (OCH CH ), 120.4 (CN), 178.3 (C=O)
MX
M
AM
2 3
4H, OCH CH ), 4.29 (dd, 4H, H ), 6.94-7.12 (m, 12H, Ar-H)
2
3
A
1.33 (t, 6H, OCH CH ), 2.93 (dd, 4H, H , J = 5.5, J = 15.7 Hz),
13.5 (OCH CH ), 28.4 (C-5), 28.9 (C-3), 56.0 (C-2 & C-6),
2 3
2
3
X
AX
MX
3.95 (dd, 4H, H , J = 10.6 Hz), 4.14 (q, 4H, OCH CH ), 4.31 (dd,
59.3 (C-4), 59.5 (OCH CH ), 118.9 (CN), 175.8 (C=O)
M
AM
2
3
2 3
4H, H ), 6.94-7.21 (m, 12H, Ar-H)
A
1.31 (t, 6H, OCH CH ), 2.91 (dd, 4H, H , J = 5.3, J = 15.7 Hz),
13.7 (OCH CH ), 27.8 (C-3 & C-5), 55.9 (C-2 & C-6), 58.4
2 3
2
3
X
AX
MX
3.94 (dd, 4H, H , J = 10.4 Hz), 4.09 (q, 4H, OCH CH ), 4.34 (dd,
(C-4), 59.7 (OCH CH ), 118.7 (CN), 174.3 (C=O)
M
AM
2
3
2 3
4H, H ), 7.05-7.21 (m, 14H, Ar-H)
A
1.33 (t, 6H, OCH CH ), 2.36 (s, 6H, CH ), 2.93 (dd, 4H, H , J
=
13.4 (OCH CH ), 20.4 (CH ), 28.3 (C-3 & C-5), 56.3 (C-2 &
2 3 3
2
3
3
X
AX
5.3, J = 15.9 Hz), 3.97 (dd, 4H, H , J = 10.6 Hz), 4.11 (q,
C-6), 58.9 (C-4), 59.5 (OCH CH ), 118.2 (CN), 173.9 (C=O)
MX
M
AM
2 3
4H, OCH CH ), 4.31 (dd, 4H, H ), 6.96-7.12 (m, 12H, Ar-H)
2
3
A
1.30 (t, 6H, OCH CH ), 2.91 (dd, 4H, H , J = 5.2, J = 15.9 Hz),
13.7 (OCH CH ), 27.8 (C-3 & C-5), 55.9 (C-2 & C-6), 58.6
2 3
2
3
X
AX
MX
3.94 (dd, 4H, H , J = 10.4 Hz), 4.13 (q, 4H, OCH CH ), 4.33 (dd,
(C-4), 59.5 (OCH CH ), 119.6 (CN), 174.2 (C=O)
M
AM
2
3
2 3
4H, H ), 7.03-7.22 (m, 12H, Ar-H)
A
7a
7b
7c
8a
8b
8c
2.93 (dd, 4H, H , J = 5.5, J = 15.7 Hz), 3.94 (dd, 4H, H , J =
28.1 (C-5), 28.4 (C-3), 54.8 (C-2 & C-6), 58.2 (C-4), 119.2
& 121.8 (CN)
X
AX
MX
M
AM
10.6 Hz), 4.32 (dd, 4H, H ), 6.96-7.21 (m, 14H, Ar-H)
A
2.35 (s, 6H, CH ), 2.94 (dd, 4H, H , J = 5.3, J = 15.8 Hz), 3.97 (dd, 20.6 (CH ), 28.3 (C-5), 28.9 (C-3), 55.8 (C-2 & C-6), 58.0 (C-4),
3
X
AX
MX
3
4H, H , J = 10.5 Hz), 4.31 (dd, 4H, H ), 6.95-7.14 (m, 12H, Ar-H)
118.2 & 121.6 (CN)
28.8 (C-5), 29.7 (C-3), 54.9 (C-2 & C-6), 59.6 (C-4), 119.4 &
121.2 (CN)
28.4 (C-3 & C-5), 54.5 (C-2 & C-6), 58.9 (C-4), 118.8 &
120.6 (CN)
M
AM
A
2.92 (dd, 4H, H , J = 5.5, J = 15.7 Hz), 3.93 (dd, 4H, H , J
=
X
AX
MX
M
AM
AM
10.7 Hz), 4.34 (dd, 4H, H ), 6.94-7.22 (m, 12H, Ar-H)
A
2.91 (dd, 4H, H , J = 5.3, J = 15.8 Hz), 3.95 (dd, 4H, H , J
=
X
AX
MX
M
10.4 Hz), 4.33 (dd, 4H, H ), 7.03-7.20 (m, 14H, Ar-H)
A
2.34 (s, 6H, CH ), 2.93 (dd, 4H, H , J = 5.5, J = 15.7 Hz), 3.96 (dd, 20.2 (CH ), 27.9 (C-3 & C-5), 55.3 (C-2 & C-6), 58.6 (C-4),
3
X
AX
MX
3
4H, H , J = 10.5 Hz), 4.32 (dd, 4H, H ), 6.98-7.11 (m, 12H, Ar-H)
119.2 & 120.8 (CN)
28.6 (C-3 & C-5), 55.3 (C-2 & C-6), 58.5 (C-4), 117.2
& 120.8 (CN)
M
AM
A
2.94 (dd, 4H, H , J = 5.3, J = 15.8 Hz), 3.95 (dd, 4H, H , J =
X
AX
MX
M
AM
10.7 Hz), 4.31 (dd, 4H, H ), 7.02-7.20 (m, 12H, Ar-H)
A

258
V. Padmavathi, D. R. C. Venkata Subbaiah and B. Jagan Mohan Reddy
Vol. 42
Phenylene)-bis-(5-aryl-4-cyanotetrahydro-2H-thiopyran-4-car-
boxylate 1,1-Dioxides) (6), 3,3 -(1,3-Phenylene)-bis-(5-aryl-
nals for methylene, methine and tertiary carbons in the
regions δ 54.5-56.4, 27.9-28.9 and 58.2-68.0, respectively,
however the compounds 3-4 exhibited signals at δ 49.9-
50.7, 51.7-52.8 which are assigned to magnetically non-
equivalent carbonyl carbons of carbomethoxy groups.
Compounds 5 and 6 also displayed signals at δ 59.3-59.7
for carbonyl carbon of carboethoxy group. On the other
hand, compounds 7 and 8 showed signal characteristic to
CN group at δ 117.2-119.2 and 120.6-121.8, respectively.
'
tetrahydro-4H-thiopyran-4,4-dicarbonitrile 1,1-Dioxides) (7) and
'
3,3 -(1,4-Phenylene)-bis-(5-aryl-tetrahydro-4H-thiopyran-4,4-
dicarbonitrile 1,1-Dioxides) (8).
To a solution of 1 mmol of the appropriate bis-[2-(2-
arylethenesulfonyl)-vinyl]-benzenes 1 or 2 and 3 mmol of
dimethyl malonate, ethyl cyanoacetate or malononitrile in 10 mL
of tetrahydrofuran, a catalytic amount of Triton-B is added and
refluxed for 3-6 hours. The reaction mixture is cooled and the
solvent is removed under reduced pressure. The syrupy substance
obtained is solidified on treatment with methanol or 2-propanol.
The resultant compound is passed through a column of silica gel
(60-120) mesh, BDH, with hexane/ethyl acetate (3:1) as eluents.
EXPERIMENTAL
Melting points were determined in open capillaries on a Mel-
Temp apparatus, and the purity of the compounds was checked
by TLC (silica gel H, BDH, ethyl acetate/hexane, 3:1). The IR
spectra were recorded on a Perkin-Elmer grating infrared
REFERENCES AND NOTES
*
To whom correspondence should be addressed: Email: vkpu-
ram2001@yahoo.com
[1] M. V. R. Reddy and S. Reddy, Synthesis, 322 (1984).
[2] M. V. Ramana Reddy, S. Reddy, D. Bhaskar Reddy and V.
Padmavathi, Synth. Commun., 19, 1101 (1989).
1
spectrophotometer, model 337 in KBr pellets. H NMR spectra
for compounds 1 and 2 were recorded in DMSO-d and for com-
6
pounds 3-8 in CDCl using 300 MHz on a Varian EM-360 spec-
3
13
trophotometer. C NMR spectra were recorded on a Varian VXR
spectrometer operating at 75.5 MHz. All chemical shifts were
reported in ppm from TMS as an internal standard. The elemental
analyses were performed at Punjab University, Chandigarh,
India.
[3] D. Bhaskar Reddy, N. Chandrasekhar Babu, V. Padmavathi
and R. P. Sumathi, Synthesis, 491 (1999).
[4] D. Bhaskar Reddy, N. Chandrasekhar Babu, K. Venugopal
Reddy and V. Padmavathi, Indian J. Chem., 40B, 416 (2001).
[5] D. Bhaskar Reddy, V. Padmavathi and M. Muralidhar Reddy,
Indian J. Chem., 31B, 407 (1992).
General Method of the Synthesis of 1,3-Bis-[2-(2-arylethenesul-
fonyl)-vinyl]-benzenes 1a-c and 1,4-Bis-[2-(2-arylethenesul-
fonyl)-vinyl]-benzenes 2a-c.
[6] D. Bhaskar Reddy, V. Padmavathi, S. Reddy and M. V.
Ramana Reddy, Sulfur Lett., 13, 123(1991).
[7] V. Padmavathi, T. V. Ramana Reddy, K. Venugopal Reddy, K.
Audisesha Reddy and D. Bhaskar Reddy, Indian J. Chem., 40B,
667(2001).
[8] D. Bhaskar Reddy, M. Muralidhar Reddy and V. Padmavathi,
Indian J. Heterocycl. Chem., 5, 11 (1995).
[9] W. Borsche, Liebig's Ann., 375, 145 (1910).
[10] E. P. Kohler and M. Reimer, Am. Chem. J., 31, 163 (1904).
[11] J. B. Conant, A. H. Bump and H. S. Holt, J. Am. Chem. Soc.,
43, 1677 (1921).
[12] E. P. Kohler and C. S. Dewey, J. Am. Chem. Soc., 46, 1267
(1924).
A solution of 2 mmol of 2-arylethenesulfonylacetic acid in 10
mL of glacial acetic acid is mixed with 1 mmol of 1,3- or 1,4-
benzenedicarboxaldehyde and 0.2 mL of benzylamine and
refluxed for 6-8 hours. The reaction mixture is cooled, treated
with 50 mL of dry ether and refrigerated overnight. Any product
separated is collected by filtration. The filtrate is diluted with 20
mL of ether and washed successively with 20 mL of a saturated
solution of sodium bicarbonate, 20 mL of sodium bisulphite, 20
mL of dilute hydrochloric acid and finally with 35 mL of water.
Evaporation of the dried ethereal layer gave a solid product,
which is purified by recrystallization from 2-propanol.
[13] D. Bhaskar Reddy, V. Padmavathi and P. V. Ramana Reddy,
Indian J. Chem., 31B, 774(1992).
[14] D. Bhaskar Reddy, V. Padmavathi, B. Seenaiah and A.
Padmaja, Heteroatom Chem., 4, 55(1993).
'
General Method of the Synthesis of Dimethyl 3,3 -(1,3-
Phenylene)-bis-(5-aryl-tetrahydro-4H-thiopyran-4,4-dicarboxy-
'
late 1,1-Dioxides) (3), Dimethyl 3,3 -(1,4-Phenylene)-bis-(5-
aryl-tetrahydro-4H-thiopyran-4,4-dicarboxylate 1,1-Dioxides)
[15] D. Bhaskar Reddy, V. Padmavathi, B. Seenaiah and M. V.
Ramana Reddy, Org. Prep. Proced. Int., 24, 21 (1992).
[16] H. H. Otto and H. Yamamura, Arch. Pharm., 308, 768 (1975).
'
(4), Ethyl 3,3 -(1,3-Phenylene)-bis-(5-aryl-4-cyanotetrahydro-
'
2H-thiopyran-4-carboxylate 1,1-Dioxides) (5), Ethyl 3,3-(1,4-