Unusual Thermolysis of Diisobutyl Polysulfides

Full text of DOI:10.1023/A:1026050405516

Russian Journal of Organic Chemistry, Vol. 39, No. 5, 2003, p. 752. Translated from Zhurnal Organicheskoi Khimii, Vol. 39, No. 5, 2003, p. 796.
Original Russian Text Copyright
2003 by Korchevina, Sukhomazova, Deryagina.
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Unusual Thermolysis of Diisobutyl Polysulfides
N. A. Korchevina, E. N. Sukhomazova, and E. N. Deryagina
Favorskii Irkutsk Institute of Chemistry, Siberian Division, Russian Academy of Sciences,
ul. Favorskogo 1, Irkutsk, 664033 Russia
e-mail: admin@irioch.irk.ru
Received October 4, 2002
Gas-phase thermolysis of dialkyl polysulfides
usually gives thiophene as the major product [1]. In
the thermolysis of dibutyl polysulfides, a small
amount (6%) of 5-methyl-1,2-dithiole-3-thione is also
formed. We have found that the major product of
thermolysis of a mixture of diisobutyl polysulfides
(i-C4H9)2Sn (n = 3 4) or each particular polysulfide
at 350 400 C is 4-methyl-1,2-dithiole-3-thione (I). Its
yield reaches 72% from diisobutyl trisulfide at 400 C.
Also, 2-methylpropane-1-thiol (10 20%), diisobutyl
sulfide (2 6%), and diisobutyl disulfide (2 17%) are
obtained.
chain in polysulfides in the heterocyclization process
which is thermodynamically favorable due to forma-
tion of pseudoaromatic system.
Thus, thermolysis of diisobutyl polysulfides is
a convenient preparative method for the synthesis
of 4-methyl-1,2-dithiole-3-thione (I).
Polysulfides were supplied in a stream of nitrogen
into a quartz flow tubular reactor (0.65 0.03 m)
which was heated in an electric furnace. Compound I
was isolated by vacuum distillation of the liquid
condensate. bp 144 146 C (3 mm), dark red liquid.
1H NMR spectrum, , ppm: 2.21 d (CH3), 8.10 d
(CH, J = 1 Hz) (cf. [2]).
REFERENCES
1. Sukhomazova, E.N., Turchaninova, L.P., Korche-
vin, N.A., Deryagina, E.N., and Voronkov, M.G.,
Zh. Org. Khim., 1990, vol. 26, p. 1225.
The scheme of formation of dithiolethione I
implies intramolecular dehydrogenation of the alkyl
2. Brown, R.F.C., Rae, I.D., and Sternhell, S., Aust. J.
Chem., 1965, vol. 18, p. 1211.
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