Syntheses of new unsymmetrical and symmetrical diaryl-sulphides and diarylsulphones containing thiazolinyl and thiazolidinonyl moieties using 4,4′-diacetyldiphenylsulphide

Article abstract of DOI:10.3390/80800622

Condensation of 4,4′-diacetyldiphenyl sulphide (2) with variable amounts of thiosemicarbazide (3) in refluxing ethanol and in the presence of catalytic amounts of dry piperidine afforded only 4-acetylthiosemicarbazone- 4′-acetyldiphenyl sulphide (5). Condensation of 2 with excess semicarbazide hydrochloride (4) in the presence of fused sodium acetate and/or piperidine yielded 4,4′-diacetylsemicarbazone diphenyl sulphide (6), whereas use of equimolar amounts of 2 and 4 afforded 4-acetyl-semicarbazone- 4′-acetyldiphenyl sulphide (7). 4-Acetylsemicarbazone-4′- acetylthiosemicarbazone diphenyl sulphide (8) was also obtained via two different routes. The effect of tautomeric structure 5d is discussed. 4-(4″-phenyl-Δ³-thiazoline-2″-acetylazino) -4′-acetyldiphenyl sulphide (9), 4-(5″-carboxyethyl-4″- thiazolidinone-2″-acetylazino)-4′-acetyldiphenyl sulphide (10), 4-(4″-thiazolidinone-2′-acetylazino)-4′-acetyldiphenyl sulphide (11) and 4-(4″-methyl-Δ³-thiazoline-2″- acetylazino)-4′-acetyldiphenyl sulphide (12) were prepared by interaction of 5 with phenacylbromide, bromodiethylmalonate, chloro ethylacetate and chloroacetone, respectively. Sulphides 9-12 were easily condensed with 3 to afford the corresponding 4-(heterocyclic moiety-2″-acetylazino)-4′- acetylthiosemicarbazone diphenyl sulphides 23-26. Oxidation of the prepared sulphides 5-7, 9-12, 23 and 25-26 using H₂O₂/glacial AcOH mixtures yielded only 4,4′-diacetyldiphenyl sulphone (13) as the main product in every case, besides 3 and 4 in certain cases. Unsymmetrical and symmetrical sulphones 14-22 were obtained starting from 13. The structures of the synthesized compounds are based on IR, ¹H-NMR, ¹³C-NMR and mass spectral data. A theoretical study on some of the prepared compounds using molecular modeling was carried out.

Full text of DOI:10.3390/80800622

Molecules 2003, 8, 622-641
molecules
ISSN 1420-3049
http://www.mdpi.org
Syntheses of New Unsymmetrical and Symmetrical Diaryl-
sulphides and Diarylsulphones Containing Thiazolinyl and
Thiazolidinonyl Moieties Using 4,4'-Diacetyldiphenylsulphide
M.A. Abbady*, Sh.H. Abdel-Hafez, M.M. Kandeel and M.I. Abdel-Monem
.Chemistry Department, Faculty of Science, Assiut University, P.O. Box 71516, Assiut, Egypt.
* Author to whom all correspondance should be addressed; e-mail: maabbady@acc.aun.edu.eg
Received: 19 March 2003; in revised form: 17 July 2003 / Accepted: 26 July 2003/ Published: 31 July
2003
Abstract: Condensation of 4,4'-diacetyldiphenyl sulphide (2) with variable amounts of
thiosemicarbazide (3) in refluxing ethanol and in the presence of catalytic amounts of dry
piperidine afforded only 4-acetylthiosemicarbazone-4'-acetyldiphenyl sulphide (5).
Condensation of 2 with excess semicarbazide hydrochloride (4) in the presence of fused
sodium acetate and/or piperidine yielded 4,4'-diacetylsemicarbazone diphenyl sulphide
(6), whereas use of equimolar amounts of 2 and 4 afforded 4-acetyl-semicarbazone-4'-
acetyldiphenyl
sulphide (7). 4-Acetylsemicarbazone-4'-acetylthiosemicarbazone
diphenyl sulphide (8) was also obtained via two different routes. The effect of tautomeric
structure 5d is discussed. 4-(4"-phenyl-∆3-thiazoline-2"-acetylazino)-4'-acetyldiphenyl
sulphide (9), 4-(5"-carboxyethyl-4"-thiazolidinone-2"-acetylazino)-4'-acetyldiphenyl
sulphide (10), 4-(4"-thiazolidinone-2'-acetylazino)-4'-acetyldiphenyl sulphide (11) and
4-(4"-methyl-∆3-thiazoline-2"-acetylazino)-4'-acetyldiphenyl sulphide (12) were prepared
by interaction of 5 with phenacylbromide, bromodiethylmalonate, chloro ethylacetate and
chloroacetone, respectively. Sulphides 9-12 were easily condensed with 3 to afford the
corresponding
4-(heterocyclic
moiety-2"-acetylazino)-4'-acetylthiosemicarbazone
diphenyl sulphides 23-26. Oxidation of the prepared sulphides 5-7, 9-12, 23 and 25-26
using H2O2/glacial AcOH mixtures yielded only 4,4'-diacetyldiphenyl sulphone (13) as
the main product in every case, besides 3 and 4 in certain cases. Unsymmetrical and
symmetrical sulphones 14-22 were obtained starting from 13. The structures of the
1
13
synthesized compounds are based on IR, H-NMR, C-NMR and mass spectral data. A

Molecules 2003, 8
theoretical study on some of the prepared compounds using molecular modeling was
623
carried out.
Keywords: Diarylsulphides, -sulphones, thiozolinyl and thiazolidinonyl moieties.
Introduction
We are interested in the chemistry of diaryl sulphides and diaryl sulphones containing different
heterocyclic and other organic moieties [1-10]. Diaryl sulphide and diaryl sulphone skeletons are not
only the key structural elements of the most widely employed class of antibacterial drugs [11-13], but
also act as building blocks in certain polymers commonly used in mouldings, coatings, adhesive
membranes, composite matrices and engineering thermoplastics [14-17]. In view of these reported
applications, there is still a tremendous demand to synthesize such title molecules. During the last
three decades considerable work from the laboratory of M.A. Abbady et al. has been published
describing the synthesis of new diaryl sulphides, diaryl sulphones, diaryl selenides and diaryl
selenones [18-19] containing varied additional moieties, as well as their evaluation as potential
pharmaceuticals.
Results and Discussion
In this communication we describe the syntheses of a series of hitherto unreported diaryl sulphides
and diaryl sulphones containing carbazone, thiazoline and thiazolidinone moieties. The starting
material for these syntheses and subsequent studies is 4,4'-diacetyldiphenyl sulphide (2), which was
prepared according to the literature method [4], and was also obtained during our attempts to acetylate
diphenyl sulphoxide (1) using the Friedel Crafts reaction [4]. Compound 2 condensed with excess of
thiosemicarbazide 3 in refluxing ethanol in the presence of a catalytic amount of piperidine as a basic
catalyst to afford only 4-acetylthiosemicarbazone-4'-acetyldiphenyl sulphide (5). Attempts to prepare
4,4'-diacetylthiosemicarbazone diphenyl sulphide (5a) starting from 2 and/or 5 using the same
condensation with 3 under a variety of conditions were unsuccessful. As an explanation for this
unexpected behaviour the mechanism illustrated in Scheme I is suggested. Thus, it is believed that
structure 5d,which has an incompletely polarized carbonyl group in 4'-acetyl group, probably
represents one of the contributing charged resonance structures of 5. The positive charge of that C=O
is shifted through π conjugation from the migration origin (which is its carbon atom) to the migration
terminus (which is the carbon atom attached to extreme -NH2 ) (with the sulphur atom acting as a relay
for conjugation) [25].
The development of positive charge at that new position is rigidly localized by the +I of -SH group
(according to Ingold terminology). It is believed that structure 5d affects the behaviour of the whole
molecule of 5 and is responsible for the previously mentioned local incomplete polarization of its
4'-C=O group, which now has low nucleophilicity; hence this decreases to a large extent the
subsequent nucleophilic attack of 3 on 5 [20,21], to a degree that prevents the second step

Molecules 2003, 8
624
condensation and/or simultaneous condensation (actually an in situ stepwise reaction) to form the
expected symmetrical sulphide 5a (Scheme II).
Scheme I
-δ
δ+
S
O
C
C O
O
C
S
C O
CH3
CH3
CH3
CH3
2a
2
3 or 4
X
-δ
δ+
S
O
C
C
N.NH.C-NH2
CH3
CH3
5b,7a
XH
N.N=C-NH2
CH3
-δ
δ+
O
C
CH3
S
C
5c,7b
XH
-δ
X = S, 5b, 5c, 5d
X = O, 7a, 7b, 7c
O
C
CH3
S
C
CH3
N=N-C-NH2
δ+
5d,7c
The proposed mechanism depicted in Scheme I is supported by the following evidence: (i)
literature precedents [24, 25]; (ii) a molecular modeling study on the more stable structure of 2, which
is not coplanar (c.f. Fig. A) [26]; (iii) the 1H-NMR of 2 (c.f. Experimental), which shows a singlet at δ
2.55-2.59 (6H, 4,4'-dimethyl) with some splitting at the top of that signal into a doublet with a
difference of ≈ δ 0.04 ppm between its two singlet peaks. This difference may be attributable to
different environments of the 4,4'-diacetyl groups of 2, which may in turn be related to cis-trans
geometrical isomerism or to the fact that the resonance structure of 2 (i.e. 2a) is not coplanar or both.
Similar results were obtained from the 1H-NMR spectrum of 13 (c.f. Experimental and Fig. B) [7,23];
(iv) the lower IR stretching frequency of the remote carbonyl group in 5 due its enolization (c.f. Table
III); (v) the 13C-NMR chemical shift of compound 5 shows a signal at δ 55 ppm that reveals that
structure 5d is the more predominant one for 5.

Molecules 2003, 8
625
In contrast to the behaviour of 2 in its condensation with 3, the former compound smoothly
condensed with excess semicarbazide hydrochloride (4) in the presence of a catalytic amount of fused
AcONa and/or piperidine to give the expected 4,4'-diacetylsemicarbazone diphenyl sulphide (6). This
formation could be interpreted via inspection of the charged contributing resonance structure 7c
(Scheme I) which has comparatively less rigidly localized developed positive charge than the
corresponding one 5d, clearly due to the lower basicity of the -OH group compared to that of the -SH
group. As a result, the 4-acetylsemicarbazone moiety in structures 7a,b,c has a comparatively little
effect on the localized polarisation of the 4'- C=O of 7, to such an extent that it permits the second step
condensation of 7 with 4 and/or simultaneous condensation of 2 with excess 4 to occur, thus with
forming 6 under a variety of conditions (Scheme II).

Molecules 2003, 8
626
Scheme II
S
S
H2N-C-NH-N
C
S
C
N-NH-C-NH2
CH3
CH3
5a
excess 3, refluxing
ethanol piperidine
O
S
CH3.C
S
C
N-NH-C-NH2
CH3
5
variable amount
of 3, refluxing
C2H5OH
AcONa,
stirring
ethanol
piperidine
S
H2N.C.NH.NH2
3
O
FC. acetylation
S
CH3CO
S
COCH3
2
1
O
H2N.HN.C.NH.HCl
4
excess 4,
stirring C2H5OH
AcONa
equimolar amounts of 4,
stirring cold C2H5OH
AcONa
O
O
H2N-C-NH-N
C
S
C N-NH-C-NH2
CH3
CH3
6
O
O
CH3.C
S
C
CH3
N-NH-C-NH2
+ 4, AcONa
7
+ 3, piperidine, C2H5OH
O
S
+ 4, AcONa
H2N-C-NH-N
C
S
C
N-NH-C-NH2
5
CH3
CH3
8
It is worth noting that two additional pieces of evidence could also clarify the previous statements.
The first chemical evidence was achieved by replacing the sulphide linkage in 5 by a sulphone one to
produce 4-acetylthiosemicarbazone-4'-acetyldiphenyl sulphone (14) (Scheme III) which was easily
condensed (second step) with 3 in refluxing ethanol in the presence of a catalytic amount of piperidine
to form 4,4'-diacetylthiosemicarbazone diphenyl sulphone (16).

Molecules 2003, 8
627
Scheme III
O
S
S
S
H2N-C-NH-N
C
C
N-NH-C-NH2
CH3
CH3
O
16
2 moles of 3,
piperidine, ethanol
reflux
2 moles of 3,
AcONa, ethanol
O
S
O
CH3.C
S
C
N-NH-C-NH2
CH3
O
14
variable amounts
of 3, piperidine/
ethanol reflux
variable amounts of
3, AcONa, ethanol cold
O
CH3CO
S
COCH3
O
13
equimolar amounts
excess of 4, ethanol,
of 4, AcONa
AcONa
O
O
O
CH3.C
S
C
N-NH-C-NH2
CH3
O
15
O
S
O
O
2 moles of 3,
piperidine, ethanol
reflux
H2N-C-NH-N
C
CH3
C
CH3
N-NH-C-NH2
O
17
O
O
S
H2N-C-NH-N
C
S
C
N-NH-C-NH2
CH3
CH3
O
18
excess 4, AcONa,
C2H5OH, cold stirring
14

Molecules 2003, 8
628
Here the sulphone group prevents the complete π conjugation through 14, which as a result
displays a rather different carbonyl group behaviour than that of 5 and even 2, and accordingly it does
not experience any effects from the carbazone moiety.
Scheme IV
S
HN
N-N
CH3
C
O
H2N.C.HN-N C
X
C
CO2C2H5
S
CH3
24
+ 3, piperidine,
C2H5OH, reflux
S
N
C Ph
H2N.C.HN-N C
CH3
X
C
CH3
N-N
S
23
O
CH3.C
N
H
C O
+ 3, piperidine,
C2H5OH, reflux
X
C
CH3
N-N
CO2C2H5
S
10, 20
O
N
C Ph
CH3.C
X
C
CH3
N-N
S
O
9, 19
BrCH(COC2H5)2
AcONa/C2H5OH
reflux
AcONa, PhCOCH2Br
C2H5OH, reflux
5 and/or 14
O
O
ClCH2COC2H5
ClCH2CCH3
AcONa, ethanol, reflux
AcONa, ethanol
O
N
H
C O
reflux
CH3.C
X
C N-N
CH3
S
11, 21
O
N
C
CH3
CH3.C
X
C
CH3
N-N
+ 3, piperidine,
S
C2H5OH, reflux
12, 22
S
HN
N-N
C O
+ 3, piperidine,
C2H5OH, reflux
H2N.C.HN-N C
X
C
CH3
S
CH3
25
S
N
C
CH3
H2N.C.HN-N C
CH3
X
C
CH3
N-N
S
26
X= S, 9, 10, 11, 12, 23, 24, 25, 26
X= SO2, 19, 20, 21, 22

Molecules 2003, 8
629
The second piece of chemical evidence comes from examination of the results when the part
containing the thione group in the thiosemicarbazone moiety of 5 was used in assembling the
heterocyclic moieties of sulphides 9-12. In these reactions the effect of the thiosemicarbazone group
was totally cancelled to a degree that permits the 4'-C=O to condense easily with 3 to produce the
sulphides 23-26 under the same conditions previously used (Scheme IV). It is interesting to note that
sulphide 5 smoothly condensed with 4 in cold ethanol containing fused AcONa to give 4-acetylthio-
semicarbazone-4'-acetylsemicarbazone diphenyl sulphide (8) which alternatively was formed by
condensation of sulphide 7 with 3 using the previously mentioned method (c.f. Experimental). The two
sulphides obtainable by two different routes (Scheme II) are identical (m.p., mixed m.p. and spectral
data). The chemical behaviour of 5 in its condensation with 4 is different than that observed with 3.
The theoretical reasoning for that difference is that it apparently depends upon the different reactivity
of 3 and 4 towards addition on 4'- C=O [22].
Condensation of 4,4'-diacetyldiphenyl sulphone 13 (vide infra) with an excess of 3 in refluxing
ethanol containing a catalytic amount of piperidine afforded only 4-acetylthiosemicarbazone-4'-acetyl
diphenyl sulphone (14) (this condensation was not accomplished using fused AcONa). A separate
second step condensation of 14 with 3 using the same conditions gave 4,4'-diacetylthiosemicarbazone
diphenyl sulphone (16). The latter stepwise formation could be explained as previously discussed and
also based on the fact that the energy needed for formation of 16 via simultaneous condensation (E=
155.5505 kcal/mol, G= 1.4838) is more than that needed for formation of 14 (which is the
monothiosemicarbazone derivative of 13) via a one step condensation (E= 17.7515; G= 14.4536) [26].
Condensation of 13 with an equimolar amount of 4 in the presence of fused AcONa smoothly yielded
4-acetylsemicarbazone-4'-acetyldiphenyl sulphone (15), while using an excess of 4, it afforded
4,4'-diacetylsemicarbazone diphenyl sulphone (17). 4- Acetylthiosemicarbazone-4'-acetylsemi-
carbazone diphenyl sulphone (18) was prepared as previously mentioned either by condensation of 15
with 3 and/or 14 with 4 (Scheme III). The two sulphones obtained by the two different routes are
identical (m.p, mixed m.p and spectral data). The structures of the prepared compounds 5-8 and 13-18
1
were established by elemental analysis, I.R, H-NMR, 13C-NMR and mass spectral data (c.f.
Experimental). It is interesting to note that the electron attracting properties of the 4,4'-diacetyl groups
in 13 are nearly equal to that of the SO2 group and that this affects the NMR data of the aromatic
protons (nearly a singlet) which is completely different from the data of the corresponding protons in
2. The same environmental comparison between sulphides 6, 8 and sulphones 17, 18, respectively, is
also valid. In the latter sulphones the electron attracting properties of the 4,4'-bis-azomethine groups
are nearly equal to that of SO2 groups in the same molecules (c.f. Experimental).
Interaction of 5 and/or 14 with phenacyl bromide in the presence of fused AcONa afforded 4-(4"-
phenyl-∆3-thiazoline-2"-acetylazino)-4'-acetyldiphenyl sulphide (9) and 4-(4"-phenyl-∆3-thiazoline-2"-
acetylazino)-4'-acetyl-diphenyl sulphone (19), respectively. Similarly, reaction of 5 and/or 14 with
bromo diethylmalonate in the presence of fused AcONa gave 4-(5"-carboxyethyl-4"-thiazolidinone-2"-
acetylazino)-4'-acetyldiphenyl
sulphide
(10)
and
4-(5"-carboxyethyl-4"-thiazolidinone-2"-
acetylazino)-4'-acetyldiphenyl sulphone (20), respectively, while reaction with chloroethylacetate in
the presence of fused AcONa gave 4-(4"-thiazolidinone-2"-acetylazino)-4'-acetyldiphenyl sulphide

Molecules 2003, 8
630
(11) and 4-(4"-thiazolidinone-2"-acetylazino)-4'-acetyldiphenyl sulphone (21), respectively. Finally,
reactions with chloroacetone in the presence of fused AcONa gave 4-(4"-methyl-∆3-thiazoline-2"-
acetylazino)-4'-acetyldiphenyl sulphide (12) and 4-(4"-methyl-∆3-thiazoline-2"-acetylazino)-4'-
acetyldiphenyl sulphone (22) respectively (Scheme IV). The 4'-acetylthiosemicarbazone derivatives of
sulphides 9-12 were used to obtain sulphides 4-(4"-phenyl-∆3-thiazoline-2"-acetylazino)-4'-acetyl-
thiosemicarbazone diphenyl sulphide (23), 4-(5"-carboxyethyl-4"-thiazolidinone-2"-acetylazino)-4'-
acetylthiosemicarbazonediphenyl
sulphide
(24);
4-(4"-carboxyethyl-4"-thiazolidinone-2"-
acetylazino)-4'-acetylthiosemicarbazone diphenyl sulphide (25) and 4-(4"-thiazolidinone-2"-
acetylazino)-4'-acetylthiosemicarbazone diphenyl sulphide (26), respectively (Scheme IV). A shortcut
to achieving that goal was by interaction of sulphides 9-12 with 3 in the presence of piperidine to
afford compounds 23-26 in moderate yields,
Oxidation of the prepared sulphides 5-12 and 23-26 using glacial AcOH/H2O2 mixtures at room
temperature for at least one week yielded only 13 as the main product from every sulphide examined,
although other compounds were isolated in some cases (see Table I). The structures 19-26 were
elucidated on the basis of elemental analyses, IR and NMR data (Tables II, III).
Table I: Oxidation products of the prepared sulphides using glacial AcOH/H2O2 mixtures.
Prepared
sulphides
Prepared
sulphides
Oxidation product(s)
13 + 3
13 + 4
13 + 4
13 + 3 + 4
Oxidation product(s)
5
11
12
23
24
25
26
13 + unidentified substance
6
13 + 3 + unidentified substance
13 + 3 + unidentified substance
13 + 3 + unidentified substance
13 + 3 + unidentified substance
13 + 3 + unidentified substance
7
8
9
13 + unidentified substance
13 + unidentified substance
10
Along with the experimental investigation and as further confirmation of the structures of the
compounds synthesized, we also carried out some theoretical studies on selected prepared compounds
with the help of molecular modeling software [26]. From the obtained data (Table IV) the parent
compound 2 (Fig. A) has energy (E)= 15.7673 kcal, Gradient, (G)= 0.099593; compound 5 (Fig. C),
the monosubstituted thiosemicarbazone derivative of 2, has E= 33.71358, G= 0.089813. By
comparison of 5 with 5a (the disubstituted dithiosemicarbazone derivative of 2, Fig. D), which has E=
24.24438, G= 0.09677 it was noted that despite the fact that 5a was not experimently obtained in the
present work under a variety of conditions for reasons were previously discussed, the theoretical
values of the latter are less than that of the former, i.e. 5a is more stable than 5. Comparing 7 (the
monosubstituted semicarbazone derivative of 2), which has E= 19.878, G= 0.0946 with 6, which has
E= 97.59393, G= 0.09596 it was found that 7 is more stable than 6 (Figs. E, F). Furthermore,
comparisons were carried out between the structures 10 (keto-form), E= 101.8926, G= 0.0957, and its

Molecules 2003, 8
631
tautomeric forms 10a (OH-form), E= 35.82579, G= 0.08946 and 10b (HN-(HO)C= form), E=
29.69458, G= 0.09995. These results proved that 10 is more stable than 10a and/or 10b and are in
accordance with the data obtained experimentally (IR, NMR, c.f. Table III).

Molecules 2003, 8
632
On the other hand, when the same comparison was repeated between the structures 11 (keto-
form), E= 27.941029, G= 0.08989 and 11a (HN-(HO)C= form), E= 35.82579, G= 0.08946, and 11b
(HN-(HO)C= form), E= 29.69458, G= 0.0995, these results proved that 11 is more stable than 11a
and/or 11b and are also in accordance with experimental data (IR, NMR, cf. Table III).
Experimental
General
The times required for the completion of the reactions and the purity of the prepared compounds
were monitored by thin layer chromatography (TLC). Melting points were determined on a Fisher-
Johns melting point apparatus and are uncorrected. Elemental analyses were performed on a Perkin-
Elmer 240C elemental analyser and a GmbH VARIOEL V23 elemental analysis system in CHNS
mode. IR spectra [27] were recorded on a Pye-Unicam SP3-100 spectrophotometer using KBr wafer
technique. 1H-NMR and 13C-NMR spectra were recorded on JNM-LA400-MHZ NMR
spectrophotometer using the appropriate deuterated solvent and TMS as internal standard (chemical
shifts expressed in δ ppm). Mass spectra were recorded on Jeol JMS-600 mass spectrometer.
4,4'-Diacetyldiphenyl sulphide (2).
This compound was prepared according to a literature method [4], or by the following procedure:
Anhydrous AlCl3 (6.66 g, 0.049 mole) was added in small portions to a conical flask containing
diphenylsulphoxide (1, 2.02 g, 0.01 mole) and acetyl chloride (2.8 mL, 0.04 mole) dissolved in carbon
disulphide (30 mL), The reaction mixture was stirred in ice bath for 6 hr. The CS2 was evaporated
under vacuum, the residue poured onto a mixture of ice and conc. HCl and the resulting pale yellow
precipitate was collected and recrystallized from pet. ether (60-80°C) as colourless flakes. Yield: 85%;
1
m.p 90-92°C; IR (ν, cm-1): 1690 (C=O); H-NMR (CDCl3): δ 2.57 (s, 6H, 2-COCH3, split into two
bands at the top with δ 2.55 and 2.59), 7.34-7.93 (m, 8H, Ar-H); Anal. Calc. for C16H14O2S: C, 70.93;
H, 5.39; S, 11.85; Found: C, 70.81; H, 5.25; S, 11.92; MS: M+, m/z (%): 270 (78%).
4-Acetylthiosemicarbazone-4'-acetyldiphenyl sulphide (5).
A mixture of 2 (1.0 g, 0.0037 mole) and 3 (0.675 g, 0.0074 mole) in ethanol (30 mL) was refluxed
for 7 hr in presence of two drops of piperidine. On cooling, yellow crystals separated from the reaction
mixture and were recrystallized from C2H5OH. Yield 74.8%; m.p 190-192°C; IR (ν, cm-1): 3400,
3300, 3200 (NH and NH2), 1640 (C=O, the lower frequency due to enolization of the remote carbonyl
1
group), 1600 (C=N); H-NMR (DMSO-d6): δ 3.22 (s, 6H, 2CH3), 4.48 (s, 2H, NH2), 7.1-7.5 (m, 8H,
Ar-H), 8.62 (s, 1H, NH); 13C-NMR: δ 18.429 (CH3-C=N); δ 27.010 (CH3-C=O); 55.928 (-C δ+);
127.109-145.571 (C-aromatic); 181.038 (-C=N-) and 197.220 (-C=O); Anal. Calc. for C17H17N3OS2:

Molecules 2003, 8
633
C, 59.47; H, 4.95; N, 12.24; S, 18.65; Found: C, 59.40; H, 4.55; N, 12.11; S, 18.61; MS: M+, m/z (%):
343 (2.2).
4,4'-Diacetylsemicarbazone diphenyl sulphide (6).
To a mixture of semicarbazide hydrochloride (0.92 g, 0.00824 mole) and AcONa (1.04 g, 0.01264
mole) dissolved in water (8 mL) a solution of 2 (0.58 g, 0.00214 mole) in ethanol was added with
continuous shaking. Ethanol was added if necessary to obtain a clear solution. Shaking was continued
for further one hour, and the mixture was cooled in the refrigerator. The separated crystals were
filtered off, washed with cold water, dried and crystallized from acetic acid. Yield 85.70%; m.p
1
>300°C (decomp.); IR (ν, cm-1): 3450, 3350, 3200 (NH, NH2), 1680 (C=O), 1580 (C=N); H-NMR
(DMSO-d6): δ 2.15 (s, 6H, 2CH3), 6.49 (s, 4H, 2NH2), 7.27-7.93 (m, 8H, Ar-H), 9.39 (s, 2H, 2NH).
Anal. Calc. for C18H20N6O2S: C, 56.25; H, 5.20; N, 21.87; S, 8.33; Found: C, 56.20; H, 5.10; N, 21.66;
S, 8.10.
4-Acetyl-4'-acetylsemicarbazone diphenyl sulphide (7).
A solution of compound 2 (0.58 g, 0.00214 mole) in ethanol was added with continuous shaking to
a mixture of 4 (0.23 g, 0.00206 mole) and AcONa (0.26 g, 0.00316 mole) dissolved in water (8 mL).
The reaction mixture was worked up as in the case of 6. The separated crystals were filtered off,
washed with cold water, dried and crystallized from ethanol, m.p 190-191°C, yield 85%; IR (ν, cm-1):
1
3470, 3150, 3160 (NH, NH2), 1695, 1665 (C=O), 1580 (C=N); H-NMR (DMSO-d6): δ 2.25 (s, 3H,
CH3-CN); 2.6 (s, 3H, O=C-CH3); 6.70 (s, 2H, NH2); 7.30-8.20 (m, 8H, Ar-H); 9.70 (s, 1H, NH); Anal.
Calc. for C17H17N3O2S: C, 63.38; H, 5.19; N, 12.84; S, 9.78; Found: C, 63.48; H, 5.13; N, 12.67; S,
9.90.
4-Acetylthiosemicarbazone-4'-acetylsemicarbazone diphenyl sulphide (8).
This compound was obtained by the following two methods:
Method A: To a mixture of 4 (0.08 g, 0.00582 mole) and AcONa (0.35 g, 0.0042 mole) dissolved in
water (≈ 8 mL), a solution of 5 (1.0 g, 0.00291 mole) in ethanol was added with continuous shaking.
The reaction mixture was worked up as in the case of 6. The crystals formed were filtered off, washed
with cold water, dried and recrystallized from AcOH, m.p >300°C (decomp.), yield 75%; IR (ν, cm-1):
3400, 3200, 3150 (NH, NH2), 1680 (C=O), 1580 (C=N), 1480 (C=S); 1H-NMR (DMSO-d6): δ 2.15 (s,
3H, CH3, acetyl thiosemicarbazone); 2.26 (s, 3H, CH3, acetylsemicarbazone); 6.48 (s, 4H, 2NH2);
7.25-8.28 (m, 8H, Ar-H); 9.36 (s, 1H, NH) and 10.26 (s, 1H, NH); Anal. Calc. for C18H20N6OS2: C,
54.00; H, 5.00; N, 21.00; S, 16.00; Found: C, 53.88; H, 4.96; N, 20.79; S, 15.93.
Method B: A mixture of 7 (1.0 g, 0.003 mole) and 3 (0.55 g, 0.0061 mole) in ethanol (30 mL)
containing two drops of piperidine was refluxed for 7 hr. On cooling the crystals that separated were

Molecules 2003, 8
634
filtered and recrystallized from AcOH, m.p >300°C (decomp.), yield 71%. The physical and spectral
data of the two products from the two methods were identical.
4-Acetylthiosemicarbazone-4'-acetyldiphenyl sulphone (14).
A mixture of 13 (1.0 g, 0.0033 mole) and 3 (0.675 g, 0.0074 mole) in ethanol (30 mL) containing a
few drops of piperidine was refluxed for 7 hr. After cooling the pale yellow crystals formed were
separated and recrystallized from ethanol, m.p 185°C, yield 80.5%; IR (ν, cm-1): 3380, 3280, 3200
(NH, NH2); 1680 (C=O); 1640 (C=N); 1335, 1160 (SO2); 1H-NMR (DMSO-d6): δ 2.58 (s, 6H, 2CH3);
4.48 (s, 2H, NH2); 7.17-8.12 (m, 8H, Ar-H) and 8.61 (s, 1H, NH); Anal. Calc. for C17H17N3O3S2: C,
54.11; H, 4.50; N, 11.11; S, 16.97; Found: C, 54.38; H, 4.36; N, 11.35; S, 16.85.
4-Acetylsemicarbazone-4'-acetyldiphenyl sulphone (15).
To a mixture of compound 5 (0.36 g, 0.0012 mole) and AcONa (0.26 g, 0.003) dissolved in water
(8 mL) a solution of 13 (1.0 g, 0.0031 mole) in ethanol was added with continuous shaking. The
reaction mixture was worked up as previously mentioned in the case of 6. The separated crystals were
filtered off, washed with cold water, dried and crystallized from ethanol, m.p 200°C, yield 82%; IR (ν,
1
cm-1): 3470, 3250, 3170 (NH, NH2); 1690, 1665 (C=O); 1580 (C=N), 1340, 1160 (SO2); H-NMR
(DMSO-d6): δ 2.60 (s, 6H, 2CH3); 4.56 (s, 2H, NH2); 7.30-8.20 (m, 8H, Ar-H) and 8.60 (s, 1H, NH);
Anal. Calc. for C17H17N3O4S:C, 56.82; H, 4.73; N, 11.69; S, 8.91; Found: C, 56.66; H, 4.59; N, 11.39;
S, 8.63.
4,4'-Diacetylthiosemicarbazone diphenyl sulphone (16).
A mixture of 14 (1.0 g, 0.0026 mole) and 3 (0.972 g, 0.01 mole) in ethanol (30 mL) containing a
few drops of piperidine was refluxed for 7 hr. After cooling the pale yellow crystals formed were
separated, crystallized from AcOH, m.p >350 (decomp.), yield 65%; IR (ν, cm-1): 3400, 3280, 3200
1
(NH, NH2); 1680 (C=O); 1620 (C=N); 1510 (C=S); H-NMR (DMSO-d6): δ 2.32 (s, 6H, 2CH3); 4.42
(s, 4H, 2NH2); 8.22 (s, 8H, Ar-H) and 10.80 (s, 2H, 2NH); Anal. Calc. for C18H20N6O2S3:C, 48.21; H,
4.46; N, 18.75; S, 21.42; Found: C, 48.11; H, 4.43; N, 18.53; S, 21.30.
4,4'-Diacetylsemicarbazone diphenyl sulphone (17).
To a mixture of 4 (1.47 g, 0.013 mole) and AcONa (0.81 g, 0.0099 mole) dissolved in water (8
mL) a solution of 13 (1.0 g, 0.00316 mole) in ethanol was added with continuous shaking. The reaction
mixture was worked up as in the case of 6. The separated crystals were filtered off, washed with cold
water, dried and crystallized from AcOH, m.p >350°C (decomp.), yield 65%; IR (ν, cm-1): 3400, 3250,
1
3100 (NH, NH2); 1680 (C=O); 1620 (C=N); 1340, 1170 (SO2); H-NMR (DMSO-d6): δ 2.23 (s, 6H,
2CH3); 6.68 (s, 4H, 2NH2); 8.12 (s, 8H, Ar-H) and 11.00 (s, 2H, 2NH); Anal. Calc. for
C18H20N6O4S:C, 51.92; H, 4.80; N, 20.19; S, 7.69; Found: C, 51.69; H, 4.21; N, 20.40; S, 7.88.

Molecules 2003, 8
635
4-Acetylthiosemicarbazone-4'-acetylsemicarbazone diphenyl sulphone (18).
This compound was prepared by the following two methods:
Method A: To a mixture of 4 (0.59 g, 0.00533 mole) and AcONa (0.32 g, 0.004 mole) dissolved in
water (≈ 8 mL), a solution of 14 (1.0 g, 0.00266 mole) in ethanol was added with continuous shaking.
The reaction mixture was worked up as in the case of 6. The separated crystals were filtered off,
washed with cold water, dried and crystallized from AcOH, m.p >350°C (decomp.), yield 77%; IR (ν,
cm-1): 3450, 3200, 3150 (NH, NH2); 1675 (C=O), 1580 (C=N); 1485 (C=S); 1340, 1160 (SO2);
1H-NMR (DMSO-d6): δ 2.23 (s, 3H, CH3); 2.52 (s, 3H, CH3); 6.50 (s, 4H, 2NH2); 7.28-7.59 (m, 8H,
Ar-H); 9.56 (s, 1H, NH) and 10.30 (s, 1H, NH); Anal. Calc. for C18H20N6O3S2: C, 50.00; H, 4.62; N,
19.44; S, 14.81; Found: C, 49.98; H, 4.55; N, 19.35; S, 14.63.
Method B: A mixture of 15 (1.0 g, 0.0027 mole) and 3 (0.50 g, 0.005 mole) in ethanol (30 mL)
containing a catalytic amount of dry piperidine (two drops) was refluxed for 6 hr. On cooling the
separated crystals were collected, dried and recrystallized from AcOH, m.p >350°C (decomp.), yield
75%. The physical and spectral data of the two products obtainable by both methods were identical.
General procedure for the oxidation of sulphides 5-12,23-26 and preparation of 13.
A solution of diarylsulphide (0.02 mole) in glacial AcOH (≈ 20 mL) was warmed if necessary,
cooled, filtered and 30% H2O2 (≈ 30 mL) was added. The mixture was kept at room temperature for 7
days and the deposited crystalline product from each oxidation was filtered, purified as usual and
1
identified as 4,4'-diacetyldiphenylsulphone (13); IR (ν, cm-1): 1690 (C=O); 1310, 1150 (SO2); H-
NMR (DMSO-d6): δ 2.57 (s, 6H, 2CH3); 8.10 (s, 8H, Ar-H). MS: M+, m/z (%): 302 (23.5); Anal. Calc.
for C16H14O4S: C, 63.57; H, 4.63; S, 10.59; Found: C, 63.44; H, 4.35; S, 10.51.
Isolation of 3 and/or 4 from the oxidation mixtures of 5 and/or 6 respectively (as representative
examples):
After filtration of 13 from the oxidation mixture of 5 and/or 6, the filtrate was neutralized with
NaHCO3 solution, the precipitate formed was filtered, purified and identified as 3. To a filtrate from
the reaction mixture of 6, conc. HCl was added (3 mL) and the reaction mixture was evaporated to a
small volume, cooled, the formed precipiate was filtered, purified and identified as 4.
General procedure for the preparation of compounds 9-12.
Compound 5 (0.5 g, 0.00145 mole) was mixed separately with (0.0014 mole) of phenacyl bromide,
bromodiethylmalonate, chloroethylacetate and chloroacetone in the presence of anhydrous AcONa (3.0
g) in ethanol (30 mL). Each mixture was refluxed for 5-7 hr, then allowed to cool and poured onto

Molecules 2003, 8
636
ice/water mixture. The precipitate solid product from every reaction was collected, crystallized from
the appropriate solvent. The results are given in Tables II, III.
General procedure for the preparation of compounds 19-22.
Compound 14 (1.0 g, 0.00266 mole) was mixed separately with (0.0026 mole) of
phenacylbromide, bromodiethylmalonate, chloroethylacetate and chloroacetone in the presence of
anhydrous sodium acetate (3.0 g) in ethanol (30 mL). Each mixture was refluxed for 5-7 hr, then
allowed to cool and poured onto ice/water mixture. The precipitated solid product of every reaction
was collected and purified from the proper solvent. The yields and characterization details for the
products of these reactions are given in Tables II-III.
General procedure for the preparation of compounds 23-26.
A mixture of each sulphide 9-12 (0.0011 mole) and thiosemicarbazide (0.2 g, 0.002 mole) in ethanol
(30 mL) containing two drops of piperidine was refluxed for 7 hr. On cooling yellow crystals were
separated from the reaction mixtures and recrystallized from the appropriate solvent. The results are
summarized in Tables II-III.
Table II: Yields and Physical data of compounds 9-12, 19-26.
M.p.
recrystallization
solvent
Molecular
formulae
(Mol. wt.)
Elemental analysis
Calcd/Found %
Compd.
No.
Yield
%
C
H
N
S
160°C,
9
decomp.
EtOH/H2O
(1:1)
54
53
C25H21N3OS2
(443)
67.72
67.90
4.74
4.52
9.48
9.70
14.44
14.32
260°C,
10
decomp.
EtOH/H2O
(1:1)
C22H21N3O4S2
(455)
58.02
58.12
4.61
4.52
9.23
9.32
14.06
13.90
11
12
19
20
21
160°C
53
52.5
62
C19H17N3O2S2
(383)
59.53
59.40
62.99
62.81
63.15
63.11
54.20
54.10
54.93
54.12
4.43
4.32
4.98
4.80
4.42
4.32
4.31
4.22
4.09
4.01
10.96 16.71
10.80 16.88
11.02 16.79
11.11 16.60
EtOH
120°C,
EtOH
>300°C
AcOH
>300°C
AcOH
>300°C
AcOH
C20H19N3OS2
(381)
C25H21N2O3S2
(475)
8.84
8.71
8.62
8.51
13.47
13.40
13.11
12.99
65
C22H21N3O6S2
(487)
61.5
C19H17N3O4S
(415)
10.12 15.42
10.11 14.99

Molecules 2003, 8
637
22
>300°C
AcOH
300°C,
EtOH/H2O
(1:1)
60
70
C20H19N3O3S2
(413)
58.11
58.10
60.46
60.31
14.60 10.16 15.49
14.30 10.15 15.32
23
C26H24N6S3
4.65
16.27 18.60
16.11 18.40
(516)
4.55
24
25
26
300°C
75
73
71
C23H24N6O3S3
(528)
52.27
52.17
52.63
52.61
55.38
55.14
4.54
4.06
4.38
4.10
5.05
4.84
15.90 18.18
15.80 18.11
18.42 21.05
18.22 20.75
18.46 21.09
18.40 20.93
EtOH
300°C
EtOH
300°C
C20H20N6OS3
(456)
C21H23N6S3
(455)
EtOH-water
(1:1)
Table III: Spectral data of compounds 9-12.
X1
X2
C
N-N=Ar
CH3
Compd.
X2
X1
Ar
Spectral data
No.
IR (ν, cm-1): 1660 (C=O), 1600 (C=N); 1H-NMR (DMSO-d6):
δ 2.27 (s, 3H, CH3-C=N), 2.30 (s, 3H, CH3CO), 4.35 (s, 2H,
CH2 of thiazoline), 7.27-7.94 (m, 13H, Ar-H).
N
C Ph
9
-S-
-S-
Acetyl
S
IR (ν, cm-1): 3400 (NH), 1700 (ester C=O), 1680 (C=O), 1580
1
HN
C
O
10
Acetyl
(C=N); H-NMR (DMSO-d6): δ 1.13 (t, 3H, CH2 ester), 2.25
S
CO2C2H5
(s, 3H, CH3-C=N), 2.52 (s, 3H, COCH3), 4.02 (q, 2H, CH2
ester), 5.36 (s, 1H, -CH of thiazoline ring), 7.30-7.99 (m, 8H,
Ar-H), 8.28 (s, 1H, NH).
IR (ν, cm-1): 3450 (NH), 1700, 1705 (C=O), 1605 (C=N);
1H-NMR (DMSO-d6): δ 2.24 (s, 3H, CH3-C=N), 2.40 (s, 3H,
CH3CO), 3.92 (s, 2H, CH2 of thiazolidenone ring), 7.00-8.00
(m, 8H, Ar-H), 8.25 (s, 1H, NH).
IR (ν, cm ): 1670 (C=O), 1590 (C=N); H-NMR (CDCl3): δ
2.25 (s, 6H, CH3 of thiazoline, CH3=C=N), 2.45 (s, 3H,
CH3CO), 6.20 (s, 2H, CH2 of thiazoline ring), 7.30-7.85 (m,
8H, Ar-H).
HN
N
C O
11
12
-S-
-S-
Acetyl
Acetyl
S
-1
1
C CH3
S

Molecules 2003, 8
638
Table III: (Continued) Spectral data of compounds 19-26.
Compd.
X2
X1
Ar
Spectral data
No.
-1
1
IR (ν, cm ): 1670 (C=O), 1600 (C=N), 1340, 1160 (SO2); H-
NMR (DMSO-d6): δ 2.28 (s, 3H, CH3-CN), 2.35 (s, 3H, CH3CO),
6.30 (s, 2H, CH2 of thiazoline ring), 7.85-7.99 (m, 13H, Ar-H).
N
C Ph
19
Acetyl
SO2
S
IR (ν, cm-1): 3450 (NH), 1710 (ester C=O), 1680 (C=O), 1340,
1160 (SO2); 1H-NMR (DMSO-d6): δ 1.30 (t, 3H, CH3 ester), 2.12
(s, 3H, CH3-C=N), 2.65 (s, 3H, CH3CO), 4.40 (q, 2H, CH2 ester),
7.99-8.35 (m, 8H, Ar-H), 8.80 (s, 1H, CH of thiazolidinone), 9.95
(s, 1H, NH).
HN
C
O
20
Acetyl
SO2
S
CO2C2H5
-1
1
IR (ν, cm ): 3450 (NH), 1710, 1700 (C=O), 1600 (C=N); H-
NMR (DMSO-d6): δ 2.21 (s, 3H, CH3CN), 2.41 (s, 3H, CH3CO),
4.00 (s, 2H, thiazolinone CH2), 7.70-7.90 (m, 8H, Ar-H), 8.95 (s,
1H, NH).
HN
N
C O
21
22
23
Acetyl
Acetyl
SO2
S
-1
1
IR (ν, cm ): 1680 (C=O), 1580 (C=N); H-NMR (CDCl3): δ
2.20, 2.30 (s, 6H, CH3 of thiazoline ring and CH3-C=N), 2.60 (s,
3H, CH3CO), 6.20 (s, 2H, CH2 of thiazoline ring), 7.85-7.90 (m,
8H, Ar-H).
C CH3
SO2
S
-1
1
IR (ν, cm ): 3450, 3260, 3150 (NH2, NH), 1600 (C=N); H-
NMR (DMSO-d6): δ 2.3 (s, 6H, 2CH3), 4.7 s, 2H, NH2), 6.30 (s,
2H, CH2 of thiazoline ring), 7.00-7.44 (m, 19H, Ar-H), 8.85 (s,
1H, NH).
Acetyl-
thiosemi-
carbazone
N
C Ph
-S-
S
IR (ν, cm-1): 3420, 3300, 3170 (NH, NH2), 1700 (C=O), 1600
(C=N); H-NMR (DMSO-d6): δ 1.3 (t, 3H, CH3 ester), 2.56 (s,
Acetyl-
thiosemi-
carbazone
HN
C
O
1
24
-S-
S
CO2C2H5
6H, 2CH3), 4.40 (q, 2H, CH2 ester), 5.14 (s, 2H, NH2), 5.40 (s,
1H, CH of thiazolidinone ring), 7.24-8.90 (m, 8H, Ar-H), 9.14 (s,
1H, NH).
IR (ν, cm-1): 3450, 3250, 3200 (NH, NH2), 1720 (C=O), 1600
Acetyl-
thiosemi-
carbazone
1
HN
N
C O
25
26
-S-
-S-
(C=N); H-NMR (DMSO-d6): δ 2.24 (s, 6H, 2CH3), 3.92 (s, 2H,
S
CH2 of thiazolidinone), 4.86 (s, 2H, NH2), 7.00-8.00 (m, 8H, Ar-
H), 8.3 (s, 1H, NH), 9.7 (s, 1H, NH).
-1
1
IR (ν, cm ): 3450, 3250, 3170 (NH, NH2), 1600 (C=N); H-
NMR (DMSO-d6): 2.3 (s, 6H, 2CH3-C=N), 2.50 (s, 3H, CH3 of
thiazoline ring), 4.7 (s, 2H, NH2), 6.20 (s, 2H, CH2), 7.20-7.90
(m, 8H, Ar-H), 8.7 (s, H, NH).
Acetyl-
thiosemi-
carbazone
C CH3
S

Molecules 2003, 8
639
Table IV: Theoretical data of compounds 2, 5, 5a, 6-11.
Compd.
No.
Gradient
(G)
Energy (∆E)
kcal/mole
Structure
O
C
S
C O
15.7673
0.099593
2
CH3
CH3
O
C
CH3
S
C
CH3
N-NH-C-NH2
33.71358
0.089813
0.09677
0.15902
5
S
24.244285
H2N-C-NH-N
S
C
CH3
S
S
C
N-NH-C-NH2
5a
6
CH3
S
O
62.47798
20.97924
24.35765
36.33211
101.8926
H2N-C-NH-N
C
CH3
C
N-NH-C-NH2
CH3
O
O
0.28384
0.094893
0.098009
0.0957
7
8
O
S
C
CH3
S
C
CH3
N-NH-C-NH2
O
H2N-C-NH-N
C
S
C
N-NH-C-NH2
CH3
CH3
N
C
C
Ph
9
O
C
CH3
S
C
N-N
CH3
S
S
N
O
H
H
10
O
C
CH3
S
C
N-N
CH3
CO2Et
N
C
OH
H
CO2Et
O
C
CH3
S
C
CH3
N-N
114.4389
0.09619
0.09985
10a
10b
S
N
C
OH
H
O
C
CH3
S
C
CH3
N-N
111.42201
S
CO2Et

Molecules 2003, 8
640
Table IV: Continued
Compd.
No.
Gradient
(G)
Energy (∆E)
Structure
kcal/mole
H
N
C
O
27.94028
35.82579
29.69458
0.08989
0.08946
0.09995
11
O
C
CH3
S
C
CH3
N-N
S
H
N
C
OH
OH
11a
11b
O
C
CH3
S
C
CH3
N-N
S
N
C
O
C
CH3
S
C
CH3
N-N
S
References and Notes
1. Abbady, M.A.; Askarie, A.; Morgan, M.; Ternary, A.L. J. Heterocyclic Chem. 1982, 19, 1473.
2. Abbady, M.A.; El-Maghraby, M.A. Indian J. Chem. 1979, 19 (B), 413-415.
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4. Abbady, M.A.; Hebbachy, R. Indian J. Chemistry 1993, 32 (B), 1119-1124.
5. Abbady, M.A.; El-Kashef, M.A.; Abd-Alla, M.A.; Kandeel, M.M. J. Chem Tech. Biotech. 1984,
34(A), 62.
6. Abbady, M.A.; Ali, M.M.; Kandeel, M.M. J. Chem. Tech., Biotech. 1991, 31, 111.
7. Abbady, M.A.; Graig, D.; Ternay, A.L.; Martin, G.E.; Galloy, J.; Watson, W.H. J. Org. Chem.
1980, 46, 1008.
8. Abbady, M.A.; Osman, A.M. J. Prak Chem. 1975, 320, 1003.
9. Abbady, M.A.; El-Ezbawy, S.R.; Radwan, Sh.M.; Bayoumy, B.E.; Khalaf, A.A. Egypt. J. Pharm.
Sci. 1986, 27, 43.
10. Abbady, M.M.; Ali, M.M.; Kandeel, M.M. Indian J. Chem. 1981, 20 B, 53.
11. Burger, A. Medicinal Chemistry, 2nd Ed.; Interscience Publishers, Inc.: N.Y. 1960.
12. Rist, N.; Compt. Rend. Soc, Biol. 1939, 130, 972 and 976.
13. Rist, N.; Bloch, F.; Hamon, V. Ann. Inst. Pasteur 1910, 61, 203.
14. Carlier, V.; Davaux, J.; Leqras, R.; Bunn, A.; McGrail, P.T. Polymer 1994, 35, 415.
15. Mani, R.S.; Zimmerman, B.; Bhatnagar, A.; Mohanty, D.K. Polymer 1993, 34, 171.
16. Attwood, T.E.; Cinderey, M.B.; Rose, J.B. Polymer 1993, 34, 2155.
17. Pak, S.J.; Lyle, G.D.; Mercier, R.; McGrath, J.E. Polymer 1993, 34, 885.
18. Abbady, M.A.; Abdel-Hafez, Sh.H. Phosphorus, Sulfur and Silicon 2000, 160, 121.
19. Abbady, M.A.; Abdel-Hafez, Sh.H.; Kandeel, M.M.; El-Emary, T.I. 8th IBN SINA, International
Conference on Pure and Applied Heterocyclic Chemistry, Luxor, Egypt, Feb. 16-19, 2002, 96.
20. (a) Lapworth, A. J. Chem. Soc. 1903, 995; (b) Lapworth, A. J. Chem. Soc. 1904, 1206.
21. Wittig, G.; Geisler, G. Ann. 1953, 580, 44.

Molecules 2003, 8
641
22. Reutov, O. Theoretical Principles of Organic Chemistry; Moscow University: Moscow, 1967; pp.
305-314.
23. The effect of temperature on the 1H-NMR spectra of compounds 2 and 13 is under further study.
24. Mangini, A.; Passerini, R. J. Chem. Soc. 1952, 1168.
25. Litvinenko, L.M.; Cheshko, R.S. J. General Chem. USSR, 1960, 30, 11.
26. Molecular mechanics calculations (MM5) were performed using the PC Model 486, version 5
computer software, available from Serena Software (Bloomington, IN, U.S.A.).
27. Bellamy, L.D. The Infrared Spectra of Complex Molecules; Methuen: London 1956.
Sample Availability: Available from the authors.
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