Selenophene synthesis in thermal reactions of dialkyl selenides with acetylene in the presence of methanol

Full text of DOI:10.1023/B:RUJO.0000034960.56827.19

Russian Journal of Organic Chemistry, Vol. 40, No. 2, 2004, pp. 290-291. Translated from Zhurnal Organicheskoi Khimii, Vol. 40, No. 2, 2004,
pp. 318-319.
Original Russian Text Copyright Ó 2004 by Deryagina, Sukhomazova, Levanova, Korchevin, Danilova.
SHORT
COMMUNICATIONS
Selenophene Synthesis in Thermal Reactions of Dialkyl Selenides
with Acetylene in the Presence of Methanol
E. N. Deryagina,E. N. Sukhomazova, E. P. Levanova, N. A. Korchevin, andA. P. Danilova
Faworsky Irkutsk Institute of Chenistry, Siberian Division, Russian Academy of Sciences
Irkutsk, 664033 Russia
e-mail: admin@irioch.irk.ru
Received March 27, 2003
Selenophene derivatives can be used as efficient anti-
oxidants, extractants for isolation and partitioning of met-
als, as polymer materials, and physiologically active sub-
stances. However the development of selenophene chem-
istry is retarded by the lack of convenient procedures for
its preparation [1].
promoted condensation of acetylene into aromatic hydro-
carbons, and their presence hampered isolation of
selenophene in a pure state.
In order to increase the selectivity of selenophene for-
mation from dimethyl or diethyl selenides and acetylene
we tried addition of methanol to the reaction system. The
addition of 10–50 mol% of methanol with respect to the
selenide ensured a stable operation of the system for sev-
eral hours affording selenophene in 72–93% yield at se-
lenide conversion of 98–100%.
We showed formerly that a gas-phase reaction of dim-
ethyl [2] or diethyl [3] selenides with acetylene at 420–
470 and 400–600°C respectively furnished selenophene
in high yield. However the yields reported in [2, 3] were
observed only in the initial period of the reaction. Then
the selenophene yield decreased because of accumula-
tion of elemental selenium in the reactor. The elemental
selenium formed in the concurrently proceeding decom-
position of the organyl selenides. Besides the selenium
Taking into consideration the data of [2, 3] and also of
earlier publications on the thermal reactions of dimethyl
sulfide [4] the selenophene synthesis may be represented
as going through a stage of vinylselenyl radicals I forma-
tion that are trapped by acetylene affording II.
(
W6H(W
H6H0H
(
W+
+
& &+6H+
+ & &+6H
+
0
+ & &+
,
+
6H
+& &+
+
6H
,,
Apparently, in spite of the acetylene excess in the sys-
tem, the vinylselenyl radicals partially decompose form-
ing the elemental selenium. Methanol plays the part of
hydrohen donor thus converting the vinylselenyl raricals
into etheneselenol that like the other unsaturated com-
pounds should be more heat resistant [5] than radicals I.
&+ 2+
&
+
&+6H+
+
&+ 2+
+& &+
+
,
,
,
6
H
Thus in the presence of methanol the vinylselenyl radi-
cals react along three paths.
&+
&+
1070-4280/04/4002-0290Ó2004 MAIK “Nauka/Interperiodica”

2
91
SELENOPHENE SYNTHESIS IN THERMAL REACTIONS
At 440 (for Et Se) and 490°C (for Me Se) reaction
3) becomes negligible, and due to reversibility of reac-
tion (1) the selectivity of selenophene formation along
reaction (2) considerably increases compared to the pro-
cess performed without methanol.
flow of acetylene (flow rate 3 l/h) was charged a mixture
of 14.7 g (107 mmol) of diethyl selenide and 0.63 g
(20 mmol) of methanol at a rate 10 ml/h for 77 min. At
the output of the reactor was collected 13.76 g of con-
densate containing according to GLC 13.43 g of
selenophene (yield 89.5%).
2
2
(
The synthesis was carried out in quartz tubular reac-
tor flushed with nitrogen prior to the experiment. It was
heated to the required temperature specified above (heat-
ing zone 30´650 mm). Into the heated reactor was charged
in an acetylene flow a mixture of Me Se (or Et Se) with
REFERENCES
1. Magdesieva, N.N., Adv. Heterocycl. Chem., 1970, vol. 12,
p. 1.
2
2
2.
Korchevin, N.A., Ostroukhova, L.A., Sukhomazova, E.N.,
Zhnikin,A.R., Deryagina, E.N., and Voronkov, M.G., Khim.
Geterotsikl. Soed., 1987, p. 279.
methanol at the molar ratio selenide–acetylene 1:2. At
the output of the reactor the products were collected in a
cooled trap (–20°C) and were analyzed by GLC on a
chromatograph LKhM-80MD at linear programming of
oven temperature. The stationary phase used was silicon
XE-60, 5% on Chromaton N-AW-HMDS, carrier gas
helium, column 2000´3 mm.
Selenophene synthesis from diethyl selenide and
acetylene in the presence of 20 mol% of methanol.
Into the above described reactor heated to 440°C in a
3. Deryagina, E.N., Sukhomazova, E.N., Levanova, E.P., and
Voronkov, M.G., Zh. Obshch. Khim., 1996, vol. 66, p. 1051.
4.
Deryagina, E.N., Sukhomazova, E.N., Bannikova, O.B., and
Voronkov, M.G., Izv. Akad. Nauk SSSR, Ser. Khim., 1979,
p. 2103.
5
. Yagupol’skii, D.P., Elementarnye reaktsii i mekhanizm
piroliza uglevodorodov (Elementary Reactions and
Mechanism of Hydrocarbons Pyrolysis), Moscow: Khimiya,
1990, p. 213.
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 40 No. 2 2004