Investigation of the addition of benzenethiol to p- chlorophenylphenylacetylene

Article abstract of DOI:10.1080/10426500500271519

The addition of benzenethiol to p-chlorophenylphenylacetylene results in the formation of a mixture of two pairs of diastereomeric (E)- and (Z)-1-p-chlorophenyl-2-phenyl-1-phenylthioethylenes (1 and 2) and (E)- and (Z)-1-p-chlorophenyl-2-phenyl-2-phenylth

Full text of DOI:10.1080/10426500500271519

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Phosphorus, Sulfur, and Silicon
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Investigation of the Addition
of Benzenethiol to p-
Chlorophenylphenylacetylene
Md. Manzoor Hussain a , Mohammed Shafi a , G.
Narayana Swamy a & S. G. Peeran a
a Department of Chemistry , Sri Krishnadevaraya
University , Anantapur, India
Published online: 15 Aug 2006.
To cite this article: Md. Manzoor Hussain , Mohammed Shafi , G. Narayana
Swamy & S. G. Peeran (2006) Investigation of the Addition of Benzenethiol to p-
Chlorophenylphenylacetylene, Phosphorus, Sulfur, and Silicon and the Related
Elements, 181:4, 763-770, DOI: 10.1080/10426500500271519
To link to this article: http://dx.doi.org/10.1080/10426500500271519
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Phosphorus, Sulfur, and Silicon, 181:763–770, 2006
Copyright © Taylor & Francis Group, LLC
ISSN: 1042-6507 print / 1563-5325 online
DOI: 10.1080/10426500500271519
Investigation of the Addition of Benzenethiol
to p-Chlorophenylphenylacetylene
Md. Manzoor Hussain
Mohammed Shafi
G. Narayana Swamy
S. G. Peeran
Department of Chemistry, Sri Krishnadevaraya University,
Anantapur, India
The addition of benzenethiol to p-chlorophenylphenylacetylene results in the for-
mation of a mixture of two pairs of diastereomeric (E)- and (Z)-1-p-chlorophenyl-
2-phenyl-1-phenylthioethylenes (1 and 2) and (E)- and (Z)-1-p-chlorophenyl-2-
phenyl-2-phenylthioethylenes (3 and 4). The configurations of these compounds
1
have been established by H NMR studies, by their preparation from benzyl
p-chlorophenyl ketone and p-chloro-benzylphenyl ketone, and by the oxidation of
the thioethylenes 1,2, 3, and 4 to the corresponding sulphonylethylenes 5, 6, 7, and
8, respectively.
Keywords (E)- and (Z)-1-p-chlorophenyl-2-phenyl-1-phenylthioethylenes; (E)- and
(Z)-1-p-chlorophenyl-2-phenyl-2-phenylthioethylenes; (E)- and (Z)-1-p-chlorophenyl-
2-phenyl-1-phenylsulphonylethylenes; (E)- and (Z)-1-p-chlorophenyl-2-phenyl-2-
phenylsulphonyl-ethylenes
INTRODUCTION
Vinylene sulphonyl compounds1 and a few mercapto haloethylene sul-
phone derivatives2 have been used as effective fungicides. Divinyl sul-
phone and hydroxydiethyl sulphone are used to give crease-resistant
finishes, and there are other sulphones that can be used as fuel addi-
tives, plasticisers, and anti-icing additives.3 This article describes the
preparation of (E)- and (Z)-1-p-chlorophenyl–2–phenyl-1-phenylthio-
ethylenes (1 and 2), and (E)- and (Z)-1-p-chlorophenyl-2-phenyl-2-
phenylthioethylenes (3 and 4) and their corresponding sulphones (5,
Received January 9, 2005; accepted June 4, 2005.
The authors are thankful to University Grants Commission (UGC) New Delhi, for the
award of the F.I.P. Fellowship to Md. Manzoor Hussain.
Address correspondence to S. G. Peeran, Sri Krishnadevaraya University, Department
of Chemistry, Anantapur, 515 003, India. E-mail: aac mh@yahoo.com
763

764
Md. M. Hussain et al.
6, 7, and 8). The configurations of these compounds have been estab-
lished by 1H NMR studies.
DISCUSSION
Unlike the addition of arenethiols to diphenylacetylene, where only a
pair of (E)- and (Z)-1-arylthiostilbenes are formed, the addition of ben-
zenethiol to p-chlorophenylphenylacetylene resulted in the formation
of two pairs of diastereomeric (E)- and (Z)-1-p-chloro-phenyl-2-phenyl-
1-phenylthioethylenes (1 and 2), and (E)- and (Z)-1-p-chlorophenyl-2-
phenyl-2-phenylthioethylenes (3 and 4) (Scheme 1).
SCHEME 1
They were separated by fractional distillation under reduced
pressure. The (E)- isomers 1 and 3 were formed selectively when com-
pared to their respective (Z)- isomers (2 and 4). The addition of thi-
ols to acetylenes were reported4−8 to yield primarily the cis- addition
products, and the trans- addition products were obtained in minor pro-
portion. The (E)- isomers 1 and 3 in the present investigation are also
sterically preferred over the corresponding (Z)- isomers 2 and 4. The for-
mation of two pairs of diastereomeric (E)- and (Z)-isomers in the present
investigation are possible because in p-chlorophenylphenylacetylene
the two acetylenic carbons are dissimilar, where both the acetylenic car-
bons can be attacked independently by the thio radical, and the addition
can be both cis and trans. The cis- addition of thiol leads to (E)- isomers

Addition of Benzenethiol to p-Chlorophenylphenylacetylene
765
and the trans- addition leads to (Z)- isomers. Out of four isomers, 1,
2, 3, and 4, the diastereomers 3 and 4 together are formed in a higher
proportion when compared to the diastereomers 1 and 2. This may be
attributed to the stabilities of the intermediate radicals involve. The
formation of compounds 3 and 4 involves the intermediate radical I,
and compounds 1 and 2 involve the intermediate radical II. The radical
I is expected to be more stable than II due to the contribution of more
of a number of resonance structures (Scheme 2). Hence, compounds
3 and 4 together are formed in higher proportion when compared to
1 and 2 Compounds 1 and 2 are also prepared from benzyl p-
chlorophenyl ketone, and 3 and 4 are prepared from p-chlorobenzyl
phenyl ketone.
SCHEME 2
Benzylphenyl ketone is known9 to react with benzenethiol forming a
mixture of (E)- and (Z)-1-phenylthiostilbenes in which the (E)- isomer
predominates. Similarly, the reaction of benzenethiol with benzyl p-
chlorophenyl ketone in the present investigation gave a mixture of (E)-
and (Z)-1-p-chlorophenyl-2-phenyl-1-phenylthioethylenes in which the
(E)- isomer predominates. The (E)- isomer has the same m.p. as 1 ob-
tained earlier, and there is no depression in the mixed melting point.
The (Z)- isomer has the same b.p. as 2, and their IR spectra were also
identical. On the other hand, the reaction of benzenethiol with p-chloro-
benzylphenyl ketone gave a mixture of (E)- and (Z)- 1-p-chlorophenyl-2-
phenyl-2-phenylthioethylenes (Scheme 1). The (E)- isomer was found to
be identical with 3 from their melting points and mixed melting point,
and (Z)-isomer was found to be identical with (4) from their b.p. and IR
spectra. All the compounds, 1, 2, 3, and 4, on oxidation with hydrogen
peroxide gave the corresponding sulphones, 5, 6, 7, and 8, respectively.
This is shown in Scheme 3.
In the UV region, the (E)- isomers absorb at a longer wavelength than
their corresponding (Z)- isomers. The εmax of the (E)- isomers are also
higher than those of their (Z)- counterparts. This is in accordance with
the generally accepted view that the (E)- isomers absorb at a longer
wavelength and εmax is also higher than the corresponding (Z)- iso-
mers. The IR spectra of all the compounds showed a weak band10 in the

766
Md. M. Hussain et al.
SCHEME 3
region of 1621–1679 cm−1 due to the C C stretching frequency (Table I).
All the compounds 1–8 showed a prominent band11 in the region of
1083–1090 cm−1 for the S-aryl group, and the sulphones 5–8 showed
sharp asymmetric and symmetric stretching frequencies12 in the region
1298–1305 and 1139–1148 cm−1, respectively, due to sulphone group.
1
Because the compounds 1–8 are trisubstituted ethylenes, in H NMR
spectra chemical shifts13,14 are used, rather than coupling constants, to
differentiate between (E)- and (Z)- isomers. The chemical shifts of vinyl
protons of cis- (E)- thioethylenes 1 and 3 occur at a lower field strength (δ
7.3 and 7.4) than their corresponding trans- (Z)- thioethylenes 2 and 4 (δ
6.9 and 7.0). Similar observations were made in β-crotonates by Peeran
and colleagues,15 in sulphide-sulphones by Stirling16 and in monosul-
phides by Peeran and colleagues. On the other hand, the chemical shifts
of the vinyl protons of cis- (E)-sulphonylethylenes 5 and 7 occur at a
higher field strength (δ 7.3 and 7.2) than their corresponding trans- (Z)-
sulphonylethylenes 6 and 8 (δ 8.0 and 7.9). A similar observation was
made in disulphones by Stirling.16 The characterisation data of all the
newly prepared compounds are presented in Table I.

767

768
Md. M. Hussain et al.
EXPERIMENTAL
Melting points were determined on Mel-Temp. apparatus, Laboratory
Devices, Cambridge, MA, USA, and are uncorrected. UV spectra were
recorded on Shimadzu Model 160A UV-visible recording Spectropho-
tometer. IR spectra on were recorded a Perkin-Elmer Infrared Spec-
trophotometer Model 983G. 1H NMR were recorded at 400 MHz with a
Bruker AVANCE instrument.
Reaction of Benzenethiol With p-Chlorophenylphenyl-
acetylene
A Solution of 21.24 g of (100 mmole) of p-chlorophenylphenylacetylene
in 150 mL of n-heptane was heated to its b.p., and 16.5 g (150 mmole)
of benzenethiol was added. The reaction mixture was refluxed for 24 h.
The solution was washed successively with 200 mL of 2% sodium hy-
droxide solution and water (250 mL) and dried over anhydrous calcium
chloride. The residue left after the evaporation of the solvent was sub-
jected to fractional distillation under reduced pressure. Four fractions
were obtained.
The first fraction upon cooling solidified and weighed 7.3 g (18.8%).
It was recrystallized from acetic acid to give needle-shaped crystals
of (E)-1-p-chlorophenyl-2-phenyl-1-phenylthioethylene (1), m.p. 80–
81◦C.
The second fraction on cooling became a pasty mass and because
solidified on treatment with n-heptane and weighed 17.8 g (45.4%). It
was recrystallized from methanol to give colorless crystals of (E)-1-p-
chlorophenyl-2-phenyl-2-phenylthioethylene (3), m.p. 41–42◦C.
The third fraction weighed 3.7 g (9.7%) and did not solidify even on
cooling or trituration with n-heptane or methanol. It was distilled under
reduced pressure, and the distillate was collected at 162–163◦C/5 mm,
which gave (Z)-1-p-chlorophenyl-2-phenyl-1-phenylthioethylene (2).
The fourth fraction was obtained as a brown viscous oil, weighed
3.9. g (10%), and was redistilled under reduced pressure. The distil-
late collected at 191–192◦C/5 mm gave (Z)-1-p-chlorophenyl-2-phenyl-
2-phenylthioethylene (4).
Preparation of (E)- and (Z)-1-p-Chlorophenyl-2-phenyl-1-
phenylthioethylenes (1 and 2) from Benzyl p-Chlorophenyl
Ketone
To a solution of 11.55 g (50 mmol) of benzyl p-chloro-phenyl ketone in
100 mL of chloroform, 13.75 g (125 mmol) of benzenethiol was added.

Addition of Benzenethiol to p-Chlorophenylphenylacetylene
769
The solution was stirred with a magnetic stirrer at r.t., and 2.26 g
(17 mmol) of anhydrous aluminium chloride was added in small por-
tions over a period of 10 min. The reaction mixture turned turbid as
the reaction proceeded. After the addition, the mixture was further
stirred for another 30 min and poured into 75 mL of water. The result-
ing mixture was extracted with 100 mL of methylene chloride, washed
with 200 mL of saturated brine, and dried over anhydrous MgSO4; the
solvent was evaporated to give 12.9 g of a light yellow oil. The light
yellow oil was treated with n-heptane, and the solid separated was fil-
tered and recrystallized from acetic acid yielding 6.8 g (42.1%) of (E)-1-
p-chlorophenyl-2-phenyl-1-phenylthioethylene (1), m.p. 80–81◦C. The
melting point of this compound was not depressed on admixture with
1 prepared earlier from p-chlorophenyl-phenylacetylene.
The n-heptane solution obtained after separating 1 on evaporation
of the solvent gave 6.1 g (37.7%) of (Z)-1-p-chlorophenyl-2-phenyl-1-
phenylthioethylene (2) as a yellow liquid. It was distilled under reduced
pressure at a b.p. of 161–162◦C/5 mm. Its b.p. and IR spectra were
identical with that of 2 obtained earlier.
Preparation of (E)- and (Z)-1-p-Chlorophenyl-2-phenyl-2-
phenylthioethylenes (3 and 4) from p-Chlorobenzylphenyl
Ketone
A solution of 16.5 g (150 mmol) of benzenethiol and 13.85 g ( 60 mmol) of
p-chlorobenzylphenyl ketone in chloroform (150 ml) was stirred at r.t.,
and 3 g (23 mmol) of anhydrous aluminium chloride was added in small
portions over a period of 15 min. The reaction mixture turned turbid
after the addition. The mixture was stirred further for another 45 min
and poured into 100 mL of water. The resulting mixture was extracted
with 150 mL of methylene chloride, washed with 200 mL of saturated
brine, and dried over anhydrous MgSO4; the solvent was evaporated to
give 17.2 g of a light yellow oil. The light yellow oil was treated with
n-heptane, and the solid separated was filtered and recrystallized from
methanol to yield 7.96 g (41.0%) of (E)-1-p-chlorophenyl-2-phenyl-2-
phenylthioethylene (3), m.p. 41–42◦C. The melting point of this com-
pound was not depressed on admixture with 3 prepared earlier from
p-chlorophenyl-phenylacetylene.
After separating the (E)-1-p-chlorophenyl-2-phenyl-2-phenylthio-
ethylene (3), the n-heptane solution on evaporation of the solvent gave
8.3 g ( 43.0%) of (Z)-1-p-chlorophenyl-2-phenyl-2-phenylthioethylene
(4) as a yellow liquid. It was distilled under reduced pressure, b.p. 191–
192◦C/5 mm. The b.p. and IR spectra of this compound was same as
that of 4 obtained earlier.

770
Md. M. Hussain et al.
General Procedure for the Oxidation of 1 and 2 to (E)- and
(Z)-1-p-Chlorophenyl-2-phenyl-1-phenylsulphonylethylenes
(5 and 6) and 3 and 4 to (E)- and (Z)-1-p-Chlorophenyl-2-
phenyl-2-phenylsulphonylethylenes (7 and 8)
A solution of 1 or 2 or 3 or 4 (2 mmol) in acetic acid (25 mL) was heated
to its b.p., and 30% hydrogen peroxide (5 mL) was added and refluxed
for 2 h. The solid separated on cooling was filtered and recrystallized
from 95% ethanol. The yields varied from 78–95% and melting points
of the sulphones thus obtained are given in Table I.
REFERENCES
[1] M. S. Raasch, U.S. Patent, 2, 979, 435 (1961); C.A., 55, 20316 h (1961).
[2] H. Bluestone and R. M. Bimber, U.S. Patent, 3, 101,377 (1963); C.A., 60, 1595d
(1964).
[3] V. E. Cates and C. E. Meloan, Anal, Chem., 35, 658 (1963).
[4] M. S. R. Naidu and S. G. Peeran, Tetrahedron, 31, 465 (1975).
[5] S. Ghouse Peeran, T. Hidayathulla Khan, and R. Venkateswarlu, Indian J. Chem.,
21B, 579 (1982).
[6] S. G. Peeran and G. Hanumantha Reddy, Phosphorus, Sulphur, and Silicon, 54, 9
(1990).
[7] H. G. Viehe, Chemistry of Acetylenes (Marcel Dekker, New York, 1969), p. 280.
[8] E. P. Gracheva, V. I. Laba, N. K. Kulbovskaya, and F. M. Shostakovskii, Zh. Obshch.
Khim., 33, 2493 (1963); C.A., 60, 399 d (1964).
[9] E. Campaigne and J. R. Leal, J. Am. Chem. Soc., 76, 1272 (1954).
[10] K. Nakanishi, Infrared Absorption Spectroscopy Practical (Holden-Day., San
Francisco, 1966).
[11] N. S. Ham, A. N. Hambly, and R. H. Laby, Australian J. Chem., 13, 443 (1960).
[12] P. M. G. Bavin, G. W. Gre´y and Stephenson, Spectrochima Acta, 16, 1312 (1960).
[13] L. M. Jackman and R. H. Willey, Proc. Chem. Soc., 196 (1958).
[14] L. M. Jackman and R. H. Willey, J. Chem. Soc., 2881, 2886 (1960).
[15] D. E. Jones, R. O. Morries, C. A. Vernon, and R. F. M. White, J. Chem. Soc., 2349
(1960).
[16] C. J. M. Stirling, J. Chem. Soc., 5856 (1964).