ISSN 1070-4280, Russian Journal of Organic Chemistry, 2009, Vol. 45, No. 5, pp. 794−795. © ©Pleiades Publishing, Ltd., 2009.
Original Russian Text © ©I.B. Rozentsveig, A.V. Popov, E.V. Kondrashov, G.G. Levkovskaya, 2009, published in Zhurnal Organicheskoi Khimii,
2
009, Vol. 45, No. 5, p. 806.
SHORT
COMMUNICATIONS
Unexpected Reaction of Dibenzyl Disulfide with Hydrazine
I. B. Rozentsveig, A. V. Popov, E. V. Kondrashov, and G. G. Levkovskaya
Faworsky Irkutsk Institute of Chemistry, Siberian Division, Russian Academy of Sciences,
Irkutsk, 664033 Russia
e-mail: i_roz@irioch.irk.ru
Received April 30, 2008
DOI: 10.1134/S1070428009050261
The reaction of hydrazine with dichalcogenides in
The examples are known of thiocarbonyl compounds
generation from disulfides: for instance, thermolysis of
dimethyl disulfide in a vacuum [3] or decomposition of
alkaline water solutions of disulfides containing a labile
hydrogen in the α-position [4, 5]. However no data on
hydrazones formation in reaction of disulfides with
hydrazine or its substituted derivatives were published.
aqueous alkaline medium is known to result in reductive
cleavage of dichalcogenides giving thiols [1] and other
chalcogenols [2], and hydrazine therewith is oxidized into
nitrogen.
We found that the reaction of dibenzyl disulfide with
excess hydrazine hydrochloride in DMF in the presence
of sodium or potassium carbonates at heating to 100°C
unexpectedly afforded benzalazine. The process was
accompanied by hydrogen sulfide evolution.
The benzalazine formation was proved by comparison
of the spectral characteristics and melting point of the
isolated product with the properties of an authentic
sample, and also was confirmed by elemental analysis.
It is presumable that under the conditions of the
reaction the dibenzyl disulfide suffered 1,2-elimination
with the formation of benzylthiol and thiobenzaldehyde.
The latter underwent condensation with hydrazine to give
the final benzalazine that apparently existed in the reaction
mixture as thioaminal or hemiaminal, but was isolated at
acidifying the reaction mixture in the individual state in
Benzalazine.Amixture of 2.46 g (0.01 mol) of dibenz-
yl disulfide, 3.15 g (0.03 mol) of hydrazine hydrochloride,
3
.18 g (0.03 mol) of sodium carbonate, and 5 ml of DMF
was stirred for 20 h at 100°C. The reaction mixture was
poured into 30 ml of water, filtered from excess dibenzyl
disulfide, the filtrate was acidified with dilute HCl to pH
5
–6 and left standing for 24 h. The precipitate was
3
8% indicating a good yield of the intermediate
thioaldehyde.
separated, washed with 5% HCl, then with water, and
dried. Yield 0.79 g (38%), mp 91–93°C. IR spectrum, ν,
–
1
1
cm : 1625 (C=N), 2950 (CH). H NMR spectrum
DMF,
(DMSO-d ), δ, ppm: 7.62, 7.99 m (10H, C H ), 8.82 s
6
6
5
o
Na CO , 100 C
13
2
3
(2H, CH=N). C NMR spectrum (DMSO-d ), δ, ppm:
6
(
PhCH S)
PhCH S
2
2
_
PhCH SH
121.30, 128.31, 128.86, 133.76 (C H ), 161.37 (C=N).
2
6
5
Found, %: C 81.03; H 5.73; N 13.62. C H N .
1
4
12
2
Calculated, %: C 80.74; H 5.81; N 13.45.
H N NH2
2
PhCHNH HNCHPh
SH
SH
1
13
H and C were registered on a spectrometer Bruker
DPX-400 (400.6, 100.61 MHz respectively), internal
reference TMS.IR spectra were recorded on a spectro-
photometr Bruker IFS-25 from samples pelletized with
KΒr.
H O, H+
2
PhCH N N CHPh
_
H2S
794
Rozentsveig
