Reaction of 1,1-dichloroethane with tellurium in the system hydrazine hydrate-potassium hydroxide

Article abstract of DOI:10.1134/S1070428009070021

The reaction of 1,1-dichloroethane with tellurium in the system hydrazine hydrate-potassium hydroxide gave ethyltellanyl derivatives as a result of replacement of one chlorine atom in the substrate by tellurium, and of the other, by hydrogen. Probable mechanisms of reduction of the C-Cl bond and mass spectra of the products were considered. The mass spectra of ditelluroacetals revealed unusual rearrangement of the molecular ion, leading to the formation of Te-Te and new C-C bond.

Full text of DOI:10.1134/S1070428009070021

ISSN 1070-4280, Russian Journal of Organic Chemistry, 2009, Vol. 45, No. 7, pp. 988–992. © Pleiades Publishing, Ltd., 2009.
Original Russian Text © E.P. Levanova, V.A. Grabel’nykh, A.V. Kolesnikov, L.V. Klyba, E.R. Zhanchipova, A.I. Albanov, N.V. Russavskaya, N.A. Korchevin,
2009, published in Zhurnal Organicheskoi Khimii, 2009, Vol. 45, No. 7, pp. 1002–1006.
Reaction of 1,1-Dichloroethane with Tellurium in the System
Hydrazine Hydrate–Potassium Hydroxide
E. P. Levanova, V. A. Grabel’nykh, A. V. Kolesnikov, L. V. Klyba, E. R. Zhanchipova,
A. I. Albanov, N. V. Russavskaya, and N. A. Korchevin
Favorskii Irkutsk Institute of Chemistry, Siberian Division, Russian Academy of Sciences,
ul. Favorskogo 1, Irkutsk, 664033 Russia
e-mail: venk@irioch.irk.ru
Received August 26, 2008
Abstract—The reaction of 1,1-dichloroethane with tellurium in the system hydrazine hydrate–potassium
hydroxide gave ethyltellanyl derivatives as a result of replacement of one chlorine atom in the substrate by
tellurium, and of the other, by hydrogen. Probable mechanisms of reduction of the C–Cl bond and mass spectra
of the products were considered. The mass spectra of ditelluroacetals revealed unusual rearrangement of the
molecular ion, leading to the formation of Te–Te and new C–C bond.
DOI: 10.1134/S1070428009070021
Reactions of tellurium with difunctional electro-
philes in the presence of reducing agents make it
possible to obtain tellurium-containing polymeric
products, which may be used in the preparation of new
materials for electrotechnics and intermediate products
for the synthesis of multidentate tellurium-containing
ligands [1, 2].
requires a large excess of alkali [KOH–Te ratio should
be equal to (6–8):1].
Telluride solutions thus obtained were brought into
reaction with 1,1-dichloroethane (I). However, we ob-
served no formation of polymeric products with the
use of K2Te or K2Te2 solution. The reaction mixture
retained its intense color even upon addition of excess
dichloride I. When tellurium was activated with excess
alkali (generation of K2Te), we isolated by extraction
two products: diethyl telluride Et2Te (yield 8%, calcu-
lated on the reacted tellurium) and diethyl ditelluride
Et2Te2 (64%). After separation of organic products, the
mixture was treated with hydrochloric acid to recover
unreacted tellurium. The conversion of tellurium was
92%. Addition of excess 1,1-dichloroethane (I) to the
reaction system containing equimolar amounts of KOH
and tellurium (generation of K2Te2) resulted in libera-
tion of elemental tellurium even during the process. By
extraction we isolated Et2Te2 in 48% yield (calculated
on the reacted tellurium). When the reaction mixture
obtained after addition of a required amount of com-
pound I (Te–I ratio 1:1) was treated with methyl
iodide (before decoloration of the hydrazine layer), the
following products were formed (according to the
GLC, GC–MS, and NMR data): Et2Te2 (yield 41%,
calculated on the reacted tellurium), Me2Te2 (14%),
MeTeEt (12%), Me2Te (1%), and Et2Te (1%). In addi-
tion, we identified methyl 1-chloroethyl telluride (II,
4%), ethyl 1-chloroethyl telluride (III, 5%), 1,1-bis-
In the present article we report on the results of our
study on unusual behavior of a geminal dihalogen
derivative, 1,1-dichloroethane, in the reaction with tel-
lurium and dimethyl ditellurides in the basic reducing
system hydrazine hydrate–potassium hydroxide. It is
known that this system generates tellurium-containing
anions from tellurium and dimethyl ditelluride [3]
(Schemes 1, 2).
Scheme 1.
2n Te
+
4KOH
+
N2H4 · H2O
N2 5 H2O
2K2Ten
+
+
n = 1, 2.
Scheme 2.
2 Me2Te2
+
4KOH
+
N2H4 ·H2O
N2 5H2O
4 MeTeK
+
+
The value of n in Ten2– depends on the KOH–Te
ratio [3]. Equimolar amounts of KOH and Te give
rise to predominant formation of potassium ditelluride
(n = 2), while selective formation of monotelluride
988

REACTION OF 1,1-DICHLOROETHANE WITH TELLURIUM
989
(methyltellanyl)ethane (IV), 1-methyltellanyl-1-ethyl-
tellanylethane (V), and methyl ethyl ditelluride
MeTe2Et, the yield of each of the three latter com-
pounds being about ~1%
may be represented as halophilic attack, as shown in
Scheme 5.
Although species VI is anionic, the possibility for
halophilic attack by Ten2– ion is determined by high
polarizability of tellurium-containing anions. The sub-
sequent transformation of [TenCl]– ion leads to libera-
tion of elemental tellurium [7]. The fact that the major
product in the reaction of dichloride I with tellurium
activated to K2Te is diethyl ditelluride implies that
participation of telluride ions in the reduction process
is more likely to follow Scheme 3. Diethyl ditelluride
is formed as a result of further transformations of
anion VII (Scheme 6).
The formation of ethyltellanyl derivatives Et2Te,
MeTeEt, Et2Te2, MeTe2Et, and compounds III and V
in the above reactions was surprising. Presumably,
generation of the EtTe fragment is preceded by re-
placement of one chlorine atom in molecule I by tel-
lurium (Scheme 3).
Scheme 3.
Ten2–
–Cl–
Me
Cl
Me
Ten
MeCH2Ten
Scheme 6.
Cl
Cl
I
VI
VII
N2H4
Et2Te2
+ NH3
n = 1
n = 1, 2.
[H]
I
EtTeCHClMe
Et2Te
VII
The transformation of anion VI into anion VII in-
volves reductive replacement of chlorine by hydrogen.
Such replacement is known to occur by the action of
various reducing agents [4]. Two kinds of reducing
agents are present in the systems under study. These
are hydrazine and telluride anions. Hydrazine is ox-
idized to extremely unstable diimide HN=NH [5]
which is also capable of acting as effective reducing
agent (Scheme 4).
n = 1
–HCl
III
[H]
I
[EtTe2CHClMe]
Et2Te2
n = 2
–HCl
When MeI is added to the reaction mixture, methyl-
tellanyl derivatives are obtained (Scheme 7).
Scheme 7.
MeI
MeTeEt
n = 1
Scheme 4.
VII
H
H
H
H
MeI
MeTe2Et
n = 2
N
N
VII
–N2H2, –HCl
Cl
The formation of compounds II, IV, and V
suggests participation of MeTe– anion which can be
generated from methyl iodide and Te2– (Scheme 8).
Me
Ten
By special experiment we showed that dichloride I
does not react with hydrazine hydrate−KOH in the
absence of tellurium. Compound I also remains un-
changed in the system S–N2H4·H2O–KOH.
Thus the main pathway in the reaction of 1,1-di-
chloroethane (I) with tellurium in the system hydrazine
Scheme 8.
n > 2
Tellurium-containing anions are also strong reduc-
ing agents, and this property is often responsible for
their unusual reactions with electrophiles [6]. Accord-
ing to [6], the reductive action of telluride anions
Ten2–
MeI
Ten –1
–I–
+
Te2–
MeTe–
+
Te2–
I
MeTeCHClMe
–Cl–
Scheme 5.
II
I
H
O
MeTe–
(MeTe)2CHMe
–Cl–
IV
H
Me
Cl
Ten2–
VII
+
(TenCl)–
III
–Cl–
–OH–
(MeTe)(EtTe)CHMe
Ten
V
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 45 No. 7 2009

LEVANOVA et al.
990
Scheme 9.
[C3H7]+
+·
·
–MeTe2
+·
Te
Te
Me
m/z 43 (2.1%)
Me
Me
MeTe
TeMe
Me
M+1·
[MeTe2]+
[Te2]+·
·
·
IV, M+·
(
130Te), m/z 318 (14.0%)
–Me2CH
–Me
m/z 275 (9.4%)
m/z 260 (7.4%)
C3H7Te·
+
m/z 145 (34.3%)
MeTe·
+ m/z 173 (23.1%)
hydrate–KOH is that leading to ethyltellanyl deriva-
tives as a result of nucleophilic replacement of one
chlorine atom in molecule I by tellurium and reductive
replacement of the other chlorine atom by hydrogen.
molecular ion, which gave rise to ions [M – 43]+
(m/z 275) and [M – 57]+ (m/z 289) together with
[C3H7]+ (m/z 43) and [C4H9]+ ( m/z 57), respectively.
The formation of these ions may be rationalized by
isomerization of the molecular ion to M+1· via formation
of Te–Te bond, as shown in Scheme 9 for compound
IV. Analogous rearrangement of the molecular ion of
V can take two pathways (Scheme 10).
The reaction of dichloride I with dimethyl ditel-
luride activated according to Scheme 2 gave the fol-
lowing products: Me2Te (8%), MeTeEt (5%), 1,1-bis-
(methyltellanyl)ethane (IV, 27%), and MeTe2Et (36%).
Also, traces of V were detected, and 12% of initial
Me2Te2 was recovered from the reaction mixture. The
above products are likely to be formed according to the
schemes proposed for the reaction with tellurium with
participation of MeTe–, Te22–, Te2–, and EtTe– anions.
We can state that ethyltellanyl derivatives are also
formed in the reaction of 1,1-dichloroethane (I) with
dimethyl ditelluride in the system N2H4·H2O–KOH.
The rearrangement is likely to be initiated by local-
ization of positive charge in the molecular ion on the
tellurium atom. Strong electron-donating properties of
tellurium atom favor charge delocalization over the
neighboring tellurium atom (transition state M1+·),
finally leading to the observed fragmentation pattern.
Compound IV is isomeric to diethyl ditelluride.
However, these compounds are characterized by differ-
ent retention times and (what is more important) by
different fragmentation patterns under electron impact.
Mono- and ditelluride derivatives Me2Te, Me2Te2,
MeTeEt, MeTe2Et, and Et2Te2 were identified by GLC,
1
GC–MS, and H and 13C NMR using authentic
Thus the reaction of 1,1-dichloroethane with tel-
lurium in the system hydrazine hydrate–potassium
hydroxide involves nucleophilic substitution of one
chlorine atom in the substrate by tellurium and reduc-
tive replacement of the second chlorine atom by hydro-
gen. Unexpected reaction products are diethyl ditel-
luride and other ethyltellanyl derivatives.
samples [9, 10]. The other compounds were identified
by GC–MS and H NMR. All the examined com-
1
pounds containing a methyltellanyl group characteris-
tically displayed in the mass spectra [MeTe]+ ion peak
cluster (m/z 145 for 130Te) with the intensity ratio
corresponding to natural distribution of tellurium
isotopes. The mass spectra of ethyltellanyl derivatives
contained ion peak clusters with m/z 159 for 130Te. If
both MeTe and EtTe groups were present, we observed
both kinds of ion peak clusters in the mass spectra.
EXPERIMENTAL
The reaction mixtures and products were analyzed
by GLC on an LKhM 80-MD-2 chromatograph
equipped with a 2000×3-mm column (stationary phase
5% of DC-550 on Chromaton N-AW-HMDS; carrier
gas helium; linear oven temperature programming at
Analysis of the mass spectra of telluroacetals IV
and V revealed an unusual fragmentation path of the
Scheme 10.
[EtTe2]+
·
1
a rate of 12 deg/min). The H, 13C, and 125Te NMR
+·
–Me2CH
Me
m/z 289 (1.9%)
spectra were recorded on a Bruker DPX-400 spectrom-
eter at 400.1, 100.6, and 126.2 MHz, respectively,
using CDCl3 as solvent and hexamethyldisiloxane as
internal reference.
EtTe
TeMe
[MeTe2]+
V, M+·
(
130Te), m/z 332 (8.1%)
·
–Me(Et)CH
m/z 275 (5.7%)
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 45 No. 7 2009

REACTION OF 1,1-DICHLOROETHANE WITH TELLURIUM
991
The mass spectra (electron impact, 70 eV) were
obtained on a Shimadzu GCMS-QP5050A instrument
(quadrupole mass analyzer, a.m.u. range 34–650).
Chromatographic separation was performed using
an SPB-5 capillary column, 60 m×0.25 mm×0.25 μm
(carrier gas helium, flow rate 0.7 ml/min, inlet pressure
150 kPa; injector and ion source temperature 250°C,
oven temperature programming from 60 to 250°C at
a rate of 10 deg/min). The m/z values for tellurium-
and chlorine-containing ions are given for 130Te and
35Cl isotopes.
filtrate was extracted with methylene chloride, and the
extract was dried over MgSO4. An additional amount
of tellurium (0.52 g) separated from the aqueous
hydrazine layer on storage. The solvent was removed
from the extract to obtain 1.7 g of a residue containing
1.64 g of diethyl ditelluride (according to the GLC and
GC–MS data).
c. A solution of 1.4 g (25 mmol) of potassium
hydroxide in 10 ml of hydrazine hydrate was heated to
80–85°C, 3.19 g (25 mmol) of powdered tellurium was
added in portions, the mixture was stirred for 3 h at
80–85°C and cooled, 6.21 g (25 mmol) of dichloride I
was added dropwise, the mixture was stirred for 3 h at
40–45°C and cooled to 25°C, and 7.1 g (50 mmol) of
methyl iodide was added. The aqueous hydrazine layer
turned colorless, and elemental tellurium separated
(2.53 g, conversion 20%). The filtrate was extracted
with methylene chloride, and the extract was dried
over MgSO4 and evaporated. According to the GC and
GC–MS data, the residue, 0.76 g, contained Me2Te,
MeTeEt, Et2Te, Me2Te2, and Et2Te2 (the yields were
given above in text), which were identical to authentic
samples. In addition, the following compounds were
identified by GC–MS, m/z (I, % of the total ion
current): methyl 1-chloroethyl telluride (II): 208 [M]+·
(15.9), 193 [M – Me]+ (1.5), 173 [M – Cl ]+ (1.8), 165
[TeCl]+ (13.2), 145 [MeTe]+ (37.4), 144 [CH2Te]+·, 130
[Te]+ (13.6), 63 [C2H4Cl]+ (16.7); ethyl 1-chloroethyl
telluride (III): 222 [M]+· (15.4), 193 [M – Et]+ (8.6),
159 [EtTe]+, 158 [C2H4Te]+· (28.5), 130 [Te]+ (27.7), 63
[C2H4Cl]+ (19.8); 1,1-bis(methyltellanyl)ethane (IV):
318 [M]+· (14.0), 275 [MeTe2]+ (9.4), 260 [Te2]+· (7.4),
173 [M – MeTe]+ (23.1), 145 [MeTe]+ (34.3), 130 [Te]+
(9.7), 43 [C3H7]+ (2.1); 1-ethyltellanyl-1-methyltel-
lanylethane (V): 332 [M]+· (8.1), 302 [M – Me]+ (0.9),
289 [EtTe2]+ (1.9), 275 [MeTe2]+ (5.7), 260 [Te2]+·
(8.4), 187 [M – MeTe]+ (13.8), 173 [M – EtTe]+ (8.0),
159 [EtTe]+ (16.0), 145 [MeTe]+ (14.1), 130 [Te]+
(14.5), 57 [C4H9]+ (4.8), 43 [C3H7]+ (3.0); methyl ethyl
ditelluride: 304 [M]+· (19.9), 289 [M – Me]+· (8.7), 275
[M – Et]+ (9.6), 260 [Te2]+· (4.4), 159 [EtTe]+ (23.2),
144 [CH2Te]+·, 145 [MeTe]+ (19.6), 130 [Te]+ (14.6).
Diethyl ditelluride. a. A solution of 35.0 g
(625 mmol) of potassium hydroxide in 110 ml of
hydrazine hydrate was heated to 80–85°C, 10 g
(78.4 mmol) of powdered tellurium was added in
portions under stirring, the mixture was stirred for 3 h
at 80–85°C and cooled, 29.1 g (294 mmol) of 1,1-di-
chloroethane (I) was added dropwise, and the mixture
was stirred for 9 h at 30–35°C, cooled to 25°C, and
extracted with methylene chloride. The extract was
dried over MgSO4 and evaporated. The residue, 5.1 g,
contained (according to the GLC data) 3.7 g of diethyl
ditelluride and 1.1 g of diethyl telluride. The aqueous
hydrazine layer (after extraction) was poured into
a mixture of ice with 180 ml of hydrochloric acid, and
the mixture was left to stand for precipitation of
tellurium. The mixture was extracted with methylene
chloride, the organic phase was separated and dried
over MgSO4, and 0.8 g of tellurium (conversion 92%)
was filtered off from the aqueous phase. The extract
was evaporated to obtain 3.7 g of a residue which
contained (GLC) 3.5 g of diethyl ditelluride. Diethyl
ditelluride was isolated by distillation of the combined
residues under reduced pressure, bp 85°C (1 mm).
Mass spectrum, m/z (I, % of the total ion current): 318
[M]+· (28.3), 289 [EtTe2]+ (27.6), 260 [Te2]+· (31.0),
1
159 [EtTe]+ (3.9), 130 [Te]+ (9.2). H NMR spectrum,
δ, ppm: 1.61 t (CH3), 3.04 q (CH2). 13C NMR spec-
trum, δC, ppm: –4.43 (CH2) (1JC,Te = 163 Hz), 19.69
(CH3). 125Te NMR spectrum: δTe 160.93 ppm. Diethyl
telluride was identified in the extract by GLC and GC–
MS data.
b. A solution of 3.51 g (62.7 mmol) of potassium
hydroxide in 25 ml of hydrazine hydrate was heated to
80–85°C, 8 g (62.7 mmol) of powdered tellurium was
added in portions, the mixture was stirred for 3 h at
80–85°C and cooled, 6.21 g (62.7 mmol) of 1,1-di-
chloroethane (I) was added dropwise, and the mixture
was stirred for 3 h at 30–35°C. The mixture was
cooled and filtered from liberated tellurium (4.7 g), the
Reaction of 1,1-dichloroethane with hydrazine
hydrate−potassium hydroxide. Compound I, 5.0 g
(50 mmol), was added dropwise at 25°C to a solution
of 2.8 g (50 mmol) of potassium hydroxide in 15 ml of
hydrazine hydrate. The mixture was stirred for 3 h at
40–45°C, and unreacted 1,1-dichloroethane (I) was
separated as organic layer. Likewise, the reaction of I
with the system S–N2H4·H2O–KOH was performed. In
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 45 No. 7 2009

LEVANOVA et al.
992
2. Russavskaya, N.V., Levanova, E.P., Sukhomazova, E.N.,
Grabel’nykh, V.A., Elaev, A.V., Klyba, L.V., Zhanchipo-
va, E.R., Albanov, A.I., Korotaeva, I.M., Toryashino-
va, D.S.-D., and Korchevin, N.A., Russ. J. Gen. Chem.,
2006, vol. 76, p. 726.
3. Deryagina, E.N., Russavskaya, N.V., Papernaya, L.K.,
Levanova, E.P., Sukhomazova, E.N., and Korche-
vin, N.A., Izv. Ross. Akad. Nauk, Ser. Khim., 2005,
p. 2395.
4. Bühler, C.A. and Pearson, D. E., Survey of Organic
Syntheses, New York: Wiley, 1970, vol. 1. Translated
under the title Organicheskie sintezy, Moscow: Mir,
1973, vol. 1, p. 620.
5. Deryagina, E.N., Korchevin, N.A., Russavskaya, N.V.,
and Grabel’nykh, V.A., Izv. Ross. Akad. Nauk, Ser.
Khim., 1998, p. 1874.
this case, 1.6 g (5.0 mmol) of powdered sulfur was
added to a solution of KOH in hydrazine hydrate. The
mixture was stirred for 6 h at 40–45°C, and unchanged
compound I was separated.
Reaction of dimethyl ditelluride with 1,1-di-
chloroethane (I). Dimethyl ditelluride, 1.98 g
(6.9 mmol), was added to a solution of 1.93 g
(34.5 mmol) of potassium hydroxide in 9 ml of
hydrazine hydrate, the mixture was stirred for 2.5 h at
80–85°C and cooled to room temperature, 0.68 g
(3.4 mmol) of 1,1-dichloroethane (I) was added, and
the mixture was stirred for 3 h at 30–35°C. After
cooling, the organic layer (0.56 g, dark red transparent
liquid) was separated, the aqueous hydrazine layer was
extracted with methylene chloride, the extract was
dried over MgSO4 and evaporated, and the residue,
1.01 g, was combined with the organic layer and
analyzed. The following compounds were identified by
GLC and GC–MS: dimethyl telluride, methyl ethyl
telluride, 1,1-bis(methyltellanyl)ethane (IV), methyl
ethyl ditelluride, 1-ethyltellanyl-1-methyltellanyl-
ethane (V), and unreacted dimethyl ditelluride (for
yields, see text). The mass spectra of compounds IV
and V and methyl ethyl ditelluride are given above.
6. Sadekov, I.D. and Minkin, V.I., Usp. Khim., 1995,
vol. 64, p. 527.
7. Russavskaya, N.V., Grabel’nykh, V.A., Levanova, E.P.,
Sukhomazova, E.N., Klyba, L.V., Zhanchipova, E.R.,
Albanov, A.I., Tatarinova, A.A., Elaev, A.V., Deryagi-
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Deryagina, E.N., and Voronkov, M.G., Metalloorg.
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