1,7-dithioxo systems. Synthetic routes to bis(5,5-dimethyl-3-thioxo-1-cyclohexenyl) sulfide

Article abstract of DOI:10.1023/A:1013837026547

Synthetic routes to bis(5,5-dimethyl-3-thioxo-1-cyclohexenyl) sulfide have been studied. The title compound can be obtained by reaction of 3-chloro-5,5-dimethyl-2-cyclohexenethione with sodium thiosulfate and by condensation of 3-mercapto-5,5-dimethyl-2-c

Full text of DOI:10.1023/A:1013837026547

Russian Journal of Organic Chemistry, Vol. 37, No. 11, 2001, pp. 1655 1658. Translated from Zhurnal Organicheskoi Khimii, Vol. 37, No. 11, 2001,
pp. 1725 1728.
Original Russian Text Copyright
2001 by Timokhina, Panova, Kanitskaya, Sokol’nikova, Toryashinova, Voronkov.
1,7-Dithioxo Systems. Synthetic Routes
to Bis(5,5-dimethyl-3-thioxo-1-cyclohexenyl) Sulfide*
L. V. Timokhina, G. M. Panova, L. V. Kanitskaya, O. V. Sokol’nikova,
D.-S. D. Toryashinova, and M. G. Voronkov
Favorskii Irkutsk Institute of Chemistry, Siberian Division, Russian Academy of Sciences,
ul. Favorskogo 1, Irkutsk, 664033 Russia
e-mail: admin.@irioch.irk.ru
Received January 2, 2001
Abstract Synthetic routes to bis(5,5-dimethyl-3-thioxo-1-cyclohexenyl) sulfide have been studied. The title
compound can be obtained by reaction of 3-chloro-5,5-dimethyl-2-cyclohexenethione with sodium thiosulfate
and by condensation of 3-mercapto-5,5-dimethyl-2-cyclohexenethione. The reaction of bis(5,5-dimethyl-3-
oxo-1-cyclohexenyl) sulfide with hydrogen sulfide and hydrogen chloride yields 3-oxo-3 -thioxobis(5,5-di-
methyl-1-cyclohexenyl) sulfide.
The first representative of unsaturated 1,7-dithiones,
bis(5,5-dimethyl-3-thioxo-1-cyclohexenyl) sulfide (I),
was synthesized by us by low-temperature reaction of
bis[5,5-dimethyl-3-(4-oxa-1-azoniacyclohexylidene)-
1-cyclohexenyl] sulfide diperchlorate (II) with hydro-
gen sulfide [1] (Scheme 1).
dithioxo sulfide I can be built up in two ways. The
first way includes introduction of thioxo groups into
molecules with already completed divinyl sulfide
framework. According to the second route, the divinyl
sulfide moiety is obtained from two fragments each
containing a thioxo group.
In the reaction of diperchlorate II with hydrogen
sulfide, apart from the major product, dithioxo sulfide
I, we isolated 20% of 3-(4-oxa-1-azoniacyclohexyli-
dene)-3 -thioxobis(5,5-dimethyl-1-cyclohexenyl) sul-
fide+(III) which was formed by thionation of only one
Scheme 1.
C N group in salt II [1]. In the present work we
have synthesized perchlorate III by another method
and studied its reaction with hydrogen sulfide. We
previously found that halogen-substituted iminium
Scheme 2.
In continuation of our studies in the field of 1,7-di-
tioxo systems having an S C C C S C C C S
fragment, in the present work we tried to develop
alternative synthetic routes to dithione I, which
could be useful for preparation of new representatives
of 1,7-dithiocarbonyl compounds. The molecule of
____________
*
This study was financially supported by the Russian Founda-
tion for Basic Research (project no. 98-03-32863a).
1070-4280/01/3711-1655$25.00 2001 MAIK Nauka/Interperiodica

1656
TIMOKHINA et al.
salts react with enaminothioketones under mild condi-
tions to give bisiminio derivatives of , -unsaturated
sulfides [2]. We have synthesized perchlorate III from
1-(3-chloro-5,5-dimethyl-2-cyclohexenylidene)mor-
pholinium perchlorate (IV) [3] and 3-mercapto-5,5-di-
methyl-2-cyclohexenethione (V) [4] (Scheme 2). The
reaction was carried out in acetonitrile at 10 C in
a continuous stream of argon. However, we failed to
obtain the desired sulfide I by treatment of salt III
with hydrogen sulfide under the same conditions as
in the synthesis of dithione I from diperchlorate II
(acetonitrile, triethylamine, 40 C, argon atmosphere).
Raising the temperature to 15 C resulted in cleavage
of the C S bond in the initial sulfide and formation
of 5,5-dimethyl-3-morpholino-2-cyclohexenethione
(VI) [5] (Scheme 3).
Traditional methods of synthesis of sulfides are
based on alkylation or arylation of inorganic sulfur
compounds [9]. In order to obtain dithioxo sulfide I
we used as alkylating agent 3-chloro-5,5-dimethyl-
2-cyclohexenethione (IX) which was synthesized by
us previously [10]. The formation of dithione I was
detected by TLC and IR spectroscopy when thione IX
was treated with anhydrous sodium thiosulfate in
methanol at 20 to 30 C (Scheme 5).
Scheme 5.
Scheme 3.
Another procedure for preparation of sulfides in-
cludes intermolecular condensation of thiols. This
reaction usually requires elevated temperature or the
presence of a catalyst [11]. We tried to synthesize
bis(5,5-dimethyl-3-thioxo-1-cyclohexenyl) sulfide (I)
from dithio analog of dimedone, which is known to
exist mainly in the form of mercaptoenethione V [4].
Compound V is fairly stable at 70 to 40 C in
an inert atmosphere. On keeping thione V at 10 C
without a solvent or in chloroform we observed evolu-
tion of hydrogen sulfide and formation of sulfide I
(Scheme 6).
The most widely used procedure for preparation of
dithiocarbonyl compounds is thionation of the corre-
sponding oxygen analogs with common sulfurization
agents [6]. By reaction of bis(5,5-dimethyl-3-oxo-1-
cyclohexenyl) sulfide (VII) [7] with hydrogen sulfide
in the presence of hydrogen chloride (methanol,
40 C) gave a complex mixture of unstable sulfur-
containing products. Analysis of the reaction mixture
Scheme 6.
by H, 13C, and two-dimensional (HETCOR) NMR
1
spectroscopy using quantitation techniques [8]
revealed formation of hitherto unknown 3-oxo-3 -
thioxobis(5,5-dimethyl-1-cyclohexenyl)sulfide (VIII)
in 26% yield (Scheme 4).
Thus, our study of alternative methods for the syn-
thesis of dithioxo sulfide I showed that the most
convenient procedure is the low-temperature reaction
of diperchlorate II with hydrogen sulfide in aceto-
nitrile in the presence of triethylamine [1]. In this case
analytically pure dithione I separates from the reaction
mixture in 70 80% yield.
Scheme 4.
EXPERIMENTAL
1
The H and 13C NMR spectra were recorded on
Jeol FX-90Q and Bruker DPX-400 instruments using
HMDS as external reference. The two-dimensional
NMR spectra (HETCOR) were obtained on a Bruker
DPX-400 spectrometer operating at 400.13 (1H) and
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 37 No. 11 2001

1,7-DITHIOXO SYSTEMS.
1657
100.6 MHz (13C). The IR spectra were recorded on
an IFS-25 spectrometer from samples pelleted with
KBr. The progress of reactions was monitored, and
the purity of products was checked, by TLC on Silufol
UV-254 plates.
Reaction of bis(5,5-dimethyl-3-oxo-1-cyclo-
hexenyl) sulfide (VII) with hydrogen sulfide. A so-
lution of 0.8 g (3 mmol) of dioxo sulfide VII in 40 ml
of anhydrous methanol was saturated with gaseous
HCl for 1 h at 40 C, and hydrogen sulfide was
passed through the solution for 10 h at 40 to 30 C.
The mixture was left to stand for 12 h at 70 C,
purged with argon at 30 C to remove HCl and H2S,
filtered, poured onto ice, and extracted with ether.
The extract was washed with ice water to pH 4 5,
dried over Na2SO4 at 5 C, and evaporated under
reduced pressure. The residue, 0.31 g, was a dark
violet thick oil with an unpleasant odor. It contained
26 1.7% of sulfide VIII. 1H NMR spectrum (CDCl3),
, ppm: 2.22 (4H, 10-H), 2.35 (4H, 6-H), 2.36 (4H,
3-(4-Oxa-1-azoniacyclohexylidene)-3 -thioxobis-
(5,5-dimethyl-1-cyclohexenyl) sulfide perchlorate
(III). A cooled solution of 0.86 g (5 mmol) of 3-mer-
capto-5,5-dimethyl-2-cyclohexenethione (V) in a mix-
ture of 10 ml of dry acetonitrile and 3 ml of dry
chloroform was added dropwise to a solution of
1.64 g (5 mmol) of 1-(3-chloro-5,5-dimethyl-2-cyclo-
hexenylidene)morpholinium perchlorate (IV) in 10 ml
of dry acetonitrile, while stirring under argon at 10 C.
The mixture was stirred for 2.5 h (until hydrogen
chloride no longer evolved) and was poured into ice
water. The product was extracted into chloroform, and
the extract was washed with ice water and dried over
CaCl2 at 5 C. The solvent was removed, and the
residue (a red brown oily substance) was washed
with cold methanol and dried in a vacuum at reduced
temperature. Yield 0.9 g (39%); dark orange powder,
decomposing at 117 121 C. The decomposition point
and 1H NMR and IR spectral parameters of the
product were identical to those reported in [1].
Found, %: C 50.91; H 7.04; Cl 7.62; N 2.27; S 13.48.
C20H30ClNO5S2. Calculated, %: C 51.78; H 6.47;
Cl 7.66; N 3.02; S 13.81.
4
12-H), 2.74 (4H, 4-H), 6.08 t (1H, 8-H, J = 1.3 Hz),
4
6.93 t (1H, 2-H, J = 1.3 Hz). 13C NMR spectrum
(CDCl3), C, ppm: 27.19 (C13), 27.55 (C14), 33.99
(C12), 34.32 (C5), 42.22 (C11), 42.37 (C6), 50.27
(C10), 59.36 (C4), 123.12 (C8), 134.14 (C2), 157.78
(C1), 158.15 (C7), 195.21 (C9), 230.67 (C3).
Reaction of 3-(4-oxa-1-azoniacyclohexylidene)-
3 -thioxobis(5,5-dimethyl-1-cyclohexenyl) sulfide
perchlorate (III) with hydrogen sulfide. Dry hydro-
gen sulfide was passed over a period of 10 min
through a solution of 0.46 g (1 mmol) of perchlorate
III in 15 ml of dry acetonitrile, cooled to 40 C.
Triethylamine, 0.02 ml, was added, and hydrogen
sulfide was passed through the mixture over a period
of 4 h at 40 C. The mixture was allowed to gradually
warm up to 15 C, and hydrogen sulfide was passed
through the mixture for an additional 4 h at that tem-
perature. The progress of the reaction was monitored
by TLC using chloroform ethyl acetate (3:1) as
eluent. The mixture was purged with argon to remove
hydrogen sulfide and was evaporated under reduced
pressure. The dark red solid residue was dissolved in
ethyl acetate, and the solution was passed through
a column charged with silica gel (40/100 mesh). The
column was eluted with ethyl acetate to isolate 0.09 g
(40%) of 5,5-dimethyl-3-morpholino-2-cyclohexene-
thione (VI) as orange crystals with mp 160 162 C
(published data [5]: mp 161 162 C). Found, %:
C 64.67; H 8.59; N 6.19; S 13.83. C12H19NOS. Cal-
culated, %: C 64.00; H 8.45; N 6.22; S 14.22.
Reaction of 3-chloro-5,5-dimethyl-2-cyclohexene-
thione (IX) with Na2S2O3. Anhydrous sodium thio-
sulfate, 0.16 g (1 mmol), was added in portions over
a period of 15 min to a solution of 0.37 g (2 mmol)
of chlorothione IX in 10 ml of anhydrous methanol,
stirred at 45 C. The mixture was allowed to slowly
warm up to 20 to 30 C and was stirred for 7 h at
that temperature. TLC analysis (eluent chloroform)
revealed formation of dithioxo sulfide I in 40 min
after the reaction started. The unreacted Na2S2O3 was
filtered off, and the filtrate was poured into 60 ml
of ice water and extracted with benzene. The extract
was washed with ice water and dried over Na2SO4.
Removal of the solvent left 0.18 g of a residue which
contained dithioxo sulfide I, initial chlorothione IX,
and a number of unidentified products. IR spectrum,
1
, cm : 1110 (C S), 1545 (C C S) (compound I);
1123 (C S), 1579 (C C) (compound IX).
Condensation of 3-mercapto-5,5-dimethyl-2-
cyclohexenethione (V). a. Compound V, 0.1 g, was
placed in a flask which was then purged with argon
and left to stand for 20 days at 10 C. TLC analysis
(eluent chloroform ethyl acetate, 3:1) showed the
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1658
TIMOKHINA et al.
presence of dithioxo sulfide I, and hydrogen sulfide
was detected via reaction with Pb(CH3COO)2.
b. A solution of 0.1 g of compound V in 10 ml
of anhydrous chloroform was stirred for 2 h at 10 to
15 C under argon. Evolution of hydrogen sulfide and
formation of dithioxo sulfide I (TLC) were observed.
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lina, E.O., and Voronkov, M.G., Zh. Org. Khim.,
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Shagun, L.G., and Usova, T.L., Zh. Org. Khim.,
1988, vol. 24, no. 11, pp. 2464 2465.
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