TRICHLOROETHYLENE IN ORGANIC SYNTHESIS: II. REACTION OF TRICHLOROETHYLENE WITH SECONDARY AMINES

Article abstract of DOI:10.1016/S0040-4020(01)96884-X

In a novel reaction, trichloroethylene reacts with secondary aliphatic amines in the presence of aqueous solution of NaOH and catalytic quantity of benzyltriethylammonium chloride to give the corresponding N,N,N',N'-tetraalkylsubstituted glycinamides.The following glycinamides were obtained with high yield: (N-morpholine)acetic acid morpholide, N-(piperidineacetyl)piperidine, N,N,N',N'-tetra-n-butylglycinamide and N,N,N',N'-tetraethylglycinamide.Mechanism of the reaction is discussed.

Full text of DOI:10.1016/S0040-4020(01)96884-X

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IN ORGANIC SYNTHESIS: II.
REACTION OF TRICHLOROETHYLENE WITH SECONDARY
JAN
and ROMAN
fnstytut Chemii
Technologii
Politechnika Krakow&a,
24, 31-155 Krakow, Poland
(Received in UK February 1984)
In a novel reaction, trichloroethylene reacts with
Abstract
secondary aliphatic
in the presence of aqueous solution
of
and catalytic quantity of benzyltriethylammonium chlo-
ride to give the corresponding
glycinamides. The following glycinamides were obtained with
high yield:
acid morpholide,
and
Mechanism of the reaction is
discussed.
INTRODUCTION
Direct, nucleophilic substitution of chlorine atoms connected to alkenyl carbon
atom is difficult, because of its low reactivity. For that reason, there are known
relatively few reactions of trichloroethylene with nucleophilic reagents, although
it does react with thiols and their salts in alkaline
dichlorovinyl thioethers or thiolosubstituted ethylenes
to give corresponding
and with or
alcoholates of alkali metal to form aryl- or alkyldichlorovinyl ethers
Benechie and Kende and
trichloroethylene with certain enolates to introduce the
Under the action of strong bases, such as
,
have applied the reaction of
group into thea-position of ketones.
triohloroethylene forms a metalloorganic compound, which with
gives
whilst aromatic Grlgnard aompounds react with
trichloroacrylic acid
in the presence of
to yield diary1 derivatives of
acetylene
16
From among the reactions of trichloroethylene with
described the reaction of trichloroethylene with aniline at 120
has
which provides
a
mixture of: anilinium chloride, hydrazobenzene, azobenzene,
and traces of dichloroacetylene. Also Rene
amino/acetylene from trichloroethylene
have obtained
dimethylamine in the presence of
sodium amide. Recently, it was reported that trichloroethylene reacts with liquid
ammonia under pressure at increased temperature to yield
or
depending on the conditions
Under phase-transfer catalytic
we have
so an
increase in the reactivity of trichloroethylene, such that one can react it with
nucleophilic reagents under
interesting, new compounds.
milder conditions than previously to give
In order to exploit this new chemistry
2671

J.
R.
ethylene, we have undertaken further studies of the reactions of trichloroethylene
under phase-transfer catalytic conditions.
In the present paper we report the
reactions of trichloroethylene with secondary
RESULTS AND DISCUSSION
During our investigations on a behaviour of polyhalogen organic compounds
under phase-transfer catalytic conditions, we have observed that trichloroethylene
unexpeotedly reaoted exothermally with morphollne to give
a
crystalline compound
which on the basis of elemental analysis, mass spectrum, and
acid morpholide,
69
IR spectroscopy showed the substance to be
formed
to summary eqation:
Cl Cl
+ 3
2
2
3
Further investigations have showed that other secondary
with trichloroethylene to give the corresponding
react similarly
in high yield (Table
according to general equation:
R
Cl Cl
+
2 ‘NH +
3
+
3
+ 2
R'
R'
R
The reaction of trichloroethylene with secondary aliphatic or alicyclic
seems to be new general method for the preparation of symmetrically substituted
a
and in
cases is superior and more convenient
23- 27.
to those hitherto known
obtained from trichloroethylene
Table 1. Substituted glycinamides:
and secondary
Yield
under phase-transfer catalytic conditions.
m.p.
dure
71
1652
a3
38
2.98
3. 26
3. 14
n-Bu
1648
1647
1655
79
51
synthesis of
chemical shift for
was reported as example in
absorption maximum situation (for carbonyl
Less nucleophilic, aromatic amine6 behave differently and an attempt to react
diphenylamine or N-methylaniline with trichloroethylene failed. When the aromatic
were heated with trichloroethylene under phase-transfer catalytic
tions however,
a gaseous product was evolved, which exploded in contact with air,
and only the unchanged
were isolated.
As the formation of
tetraalkylglyoinamides from the reactions of the
with trichloroethylene under the conditions for the
secondary
anionic reactions was surprising, we have attempted to explain the mechanism.
benzyltriethylammonium chloride.

Trichloroethylene in organic synthesis-11
2673
As reported
in the presence of
and aqueous sodium hydroxide,
trichloroethylene easily forms the trichlorovinylic anion
Cl Cl
Cl Cl
a
Direct reaction of anion
with amine is impossible, because of both
but dichlorcacetylene
formed as a result of decay of anion
at
increased (above
temperatures,
capable to reaction with the amine.
Cl Cl
Cl-cat-Cl + Cl
We have
the isolation of dichloroacetylene in high yield as a
complex with diethyl ether from the reaction of trichloroethylene under
transfer catalytic conditions in the absence of aliphatic
and hence, in the case of less reactive
it is the volatile dichloroacetylene, which explodes in the
condenser, whereas aliphatic react instantenously with the highly
lene forms an explosive mixture with
aromatic
dichloroacetylene with the same energy as acid chlorides to give
\
+
The
are highly unstable in the presence of
and are
hydrolyzed in the alkaline medium to yield
chloroacetamides
which react with a second molecule of the amine to give the
glycinamide
0 R
+
R
0
enolic form of
In order to confirm the proposed mechanism, attempts were undertaken to isolate
the intermediate compounds Neither of compounds and could be isolated
from the reaction mixture in pure form, because of their unstability under
reaction conditions. Although, in of morpholine reaction with
temperature, extraction of products with benzene gave
lene at
which, when dropped on
a
solution,
a filter paper,
spontaneously became yellow, then brown-red
and
was secreted. An attempt to-distill off the solvent resulted in an
explosion and the formation of dark-brown, viscous substance. Similar behaviour
has been observed previously for
Moreover, when the extract
shaken with water, the aqueous phase became acidic
from released It is therefore possible that
ethylene was present in the solution. The observed behaviour can be explained by
decomposition with loss of from dichloroenamine and the formation of the
chloroinamine which cationically polymerized to give the dark, viscous product.
In the case of the morpholine reaction with trichloroethylene we have isolated
and identified pure intermediate in a low yield.
It, as well as above mentioned observations, confirm the postulated mechanism.

J.
and R.
EXPERIMENTAL
spectra were recorded on
reference standard and the chemical shifts are expressed in t-values (ppm) down-
field from The IR were recorded on a Carl-Zeiss UR-20
meter. Mass spectra were recorded on LKB mass spectrometer.
lyses were performed on Perkin-Elmer 240 microanalyzer. and
a
Tesla
spectrometer. TMS was used as internal
are
Materials: Trichloroethylene and diethylamine (POCH), df-n-butylamine and
morpholine
and plperidine
BDH Ltd.) were obtained commercially.
Benz
triethylammonium chloride was synt eslzed according to
reactants and solvents were distilled before use.
procedure.
he
acid
8a. In a 250 ml round bottom flask
equipped with an efficient stirrer, thermometer and upright condenser were placed
a solution of 50 g
mole)
in 50 ml water, 43.5 ml mole) morpholine
chloride Cl-) 2 ml water.
and 1.1
The
(0.005 mole)
was stirred and-heated up to 70°C and 22.5 ml (0.25 mole)
ethylene was added dropwlse
the upright oondenser. The temperature was
maintained between 70 and 100 C and the reaction flask was cooled if necessary.
After all of trichloroethylene was added (2
the reaction mixture was
for
hour. The water was then evaporated from the mixture under slightly reduced
pressure end the residue was extracted with 500 ml
. The extract
69-70 C (lit.
d r i e d
wit h
SO and evaporated from a water bath to
from ligroine. Yield: 38 g,
which was
MS: m/e
Found:
calcd for
8b. This was obtained as for 8a from 22.5 ml
mole) trichloroethylene and 49.5 ml
mole)
Main part of
(0.25
crude 8b was isolated by separation of organic layer, after the reaction had
Additional part was obtained from the water phase as for 8a. Crude 8b
It is recommended to cool the
was recrystallized from ligroine.
Yield: 43.5 g
losses.
calcd:
avoid
210.3, m.p. 38 C (lit.23: 38-9, lit.26:
calcd for
.
compound was obtained as for
ml (0.23 mole di-n-butylamine, 10.5 ml (0.117 mole)
(0.5 mole) 50 % in the presence of (0.0025 mole
from
Cl
lene
g
The temperature was maintained between 100 and 120 C. After the reaction finished,
the
was extracted with benzene
x 50 ml). The extracts were dried with
Na SO and the solvent was evaporated. The residue was distilled under vacuum.
Found:
calcd for
28.5 g
1 cinamide 8d. This was obtained as for
from 52 ml (0.5
mole)
mole) diethylamine, ml trichloroethylene
g
The reaction was conducted at the boiling point of diethylamine. The
extraction was made with chloroform (3 x 150 ml). Yield: 37
Found:
calcd for
.
7a. The reaction was carried out in the same apparatus
k were placed 22.5 ml (0.25 mole) 22 ml
a solution of 1.1 g (0.005 mole) TEBA Cl' in 2 ml water.
To the mixture was added a solution of 40 g mole) 50 ml wager
within hour. The flask was cooled such that the temperature didn't exceed 30 C.
After all of the solution had been added, stirring was continued for a further
I th
1
2 hours. Then 60 ml benzene was added and after stirring 5
the organic layer
was separated. It consisted of in addition to the unreacted substrates,
chloro-I-(N-morpholino)ethylene, which behaved as described in the preceding
section. The extract was shaken with 100 ml water for
hour and
t h en
The
was evaporated and the residue was
separated and dried with
distilled under vacuum. Yield: 7 g (17
0
Found:
calcd
. IR: V
4:

in organic synthesis-11
2675
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Monatsh
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M.Benechie,
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