Note: Descriptions are shown in the official language in which they were submitted.
~2~
Field of Industrial Application
The present invention relates to a process for the
preparation of 3-phenoxybenzyl 2-~4-alkoxyphenyl)-2-methyl-
propyl ethers represented by the following ~ormula (I)~
CH3 /--~,<
RO~ CHz OCHz--@< g2 ( I )
CH3 ~L
S wherein R stands for a lower alkyl group, and X1 and
X2 stand for a hydrogen atom or fluorine atom.
A 3-phenoxybenzyl ether type derivative represented
by the formula (I) is an excellent pest-controlling agent
having very high insecticidal and acaricidal activities,
being excellent in the immediate effect and residual effect
of being less koxic to not only men and domestic animals
but als:o fish.
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prior Art
A process for the preparation of a compound of ~he
formula (I) having an alkoxy group on the benzene nucleus
of the neophyl group is disclosed in Japanese Pate.nt
5 Application Laid-Open Specification No. 1~4427/81, and it
is taught that the neophyl derivative can be prepared by
condensing a compound represented by the following formula
(III):
C H3
~ - ¢ -C H~O H (m)
R O C Hl
with a 3-phenoxybenzyl halide or alcohol or by condensing
a compound represented by the following formula (IV):
C H3
~ C H2g t~)
R O C H3
.
wherein X stands for a halogen atom, with a 3-
phenoxybenzyl alcohol~
The reaction path for the synthesis of the compound
of the formula (III) is long, and the process for preparing
the compound of the formula (I) from the compound of the
formula ~ as the starting material is disadvantageous
from the industrial viewpoint.
As the process for preparing the compound of the
; formula (IY), for example, the above-mentioned laid-open
specification discloses a process represented by the
following reaction formulas:
.
,
.
.
7~k
-- 3 --
(1) CH3 sul rurylC Hl
chloride ~ ~--¢--CH2C Q
RO CH, RO C}I3
(2) C~:-2 CX3
~ + C ~ C ~,2 C Q e ~>--C--C ~I. Ç Q
RO CH~ RO CH3
However, in the case where the 4-position is substituted
with a lower alkoxy group, acco~ding to the process of the
reaction for~ula (1), a nuclear chlorina~ion reaction is
preferentially advanced, and the intended 4-alko~yneophyl
chloride is in only a very poor yield obtained. Further-
more, according to ~he proces~ o~ the react~on ~orm~la
(2), an alXylation re~c~ion ~t the ortho-posi~ion to the
~lkoxy group is pr~erentlally advanced and a large quan-
tity cf an oratho-~so~er is ~ormed as a by-product, and
since effective separation of the i~omers is difficult,
the intended 4-alkoxyn~ophyl chloride having a high purity
can be obtained only in a very low yield.
Moreover, the obtained 4-alkoxyneophyl chloride is `.
an unstable compound, and storage and han~ling thereof on
an industrial scale involve various difficulties.
As the improved process for overcoming the foregoing
disadvantages, Japanese Patent Application Laid-Open
Specification No. 73535/84 proposes a process in which a
4-alkoxyhalogenoneophyl halide having at leas~ one chlorine
or bromine atom substitu~ed at the ortho-position to the
alkoxy group is used and ~his compound is reaated with a
3-phenoxybenzyl alcohol to obtain a compound of the formula
(II) and a compound of ~he formula (I) is obtained from
this compound of the formula tII).
B~ ~ :
,~
.
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. ~ . . . . .
7~
-- 3A --
Y~, C~ ~o-~
R ( ) ~ <~--C--C H2 O C H~ z
Yl CH, ~:1
wherein R stands for a lower alkyl group, X1 and X2 stand
for a hydrogen atom or ~luorine atom, and Y1 and Y2 stand
for a hydrogen atom, chlorine atom or bromine atom, wi~h
the proviso that at least one of Y1 and Y2 is a chlorin~
atom or bromine atom.
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In this laid-opPn speci~ication, it is taught that
the compound of the ~ormula (I) is obtained by subjecting
the compound of the formula (II~ to catalytic hydrodehalo-
genation using hydrogen in a solvent such as methanol in
the presence of a hydrogenation catalyst ~uch as palladium
and a base as the dehydrohalogenating agent.
The fatal defect of this process i8 that hydrogen
gas is used at the dehalogenating step. Namely, in the
case where this process is worked on an industrial scale,
special care should be taken to maintain safety and the
location is limited because hydrogen gas-supplying equip-
ment is necessary. Moreover, large equipment expenses are
necessary and hence the process is disadvantageous also
from the economical viewpoint.
In the catalytic hydrogenation reaction using
hydrogen, cleaving is readily cau~ed in a compound having
an 0 benzyl group and a fluorine atom, such as the compound
of the ~ormula (II), unless the hydrogenation conditions
are strictly controlled. It has been found that this
tendency is especially prominent when a palladium type
catalyst, which i~ know~ to be preferred as a dehalogen-
ation catalyst, is used.
As the process not using hydrogen, there may be
considered a process in which a known reducing agent such
as sodium formate is used. However, it has been found
that even if the compound of the formula (II) used in the
present invention is reacted with sodium formate as the
reducing agent, the unreacted substance and the by-product
formed by cleaving of the ether linkage are contained in
large quantities in the dehalogenation reaction liquid.
Means for Solvinq the Problems
We made research on the process for obtaining the
compound of the formula (I) by removing chlorine, bromine
,
. . : .
: . .. . .
-: . . .
74
-- 5 --
or iodine from the compound of the formula (II) by hydro-
dehalogenation reaction, and as the result, it was found
that if an alkali compound and an alcohol are present in
amounts larger than the stoichiometrically necessary
amounts in the presence of a hydrogenation catalyst,
hydrogen gas need not indispensably be added to the re~
action and the reaction can be advanced only by hydrogen
generated from the alkali and alcohol, and to our great
surprise it also was found that the dechlorination or
debromination reaction can be carried out in a yield
comparable to or higher than the yield attained in thP
process using hydrogen gas supplied from outside of the
reaction system, disslosed in the above-mentioned laid-
open specification. We have now completed the present
invention based on these findings.
Since hydrogen gas supplied from outside of the
reaction system is not used, the process of the present
invention is much safer and is advantageous from the eco-
nomical viewpoi~t over the process using hydrogen gas
supplied from outside of the reaction system. By dint of
this advantage and high functional utili~y of compounds
prepared according to the process of ~he present invention,
the process of the present invention has a very high
industrial value.
In the hydrodehalogenative reduction reaction of the
present invention, in order to obtain the intended compound
of the formula (1) in a high yield without using hydrogen
gas supplied from outside of the reaction system, an alkali
metal or alkaline earth metal hydroxide and a lower ali-
phatic alcohol should be used in combination besides a
hydrogenation catalyst and a customarily used dehydrohalo~
genating agent as a base. The reason is presumed to be as
follows:
For example, when sodium hydroxide is used as the
alkall metal hydroxide and methanol is used as the lower
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- 6 -
aliphatic alcohol, sodium hydroxide i5 reacted with
methanol in ~he presence o~ a hydrogenation ca~alyst to
form formic acid and this formic acid is decomposed to
sodium formate and finally to sodium carbonate. At this
time, stoichiometrically speaking, by using 2 moles of
sodium hydroxide per mole of methanol, 3 moles of hydrogen
is finally formed, and this hydrogen acts efficiently on
the dehalogenation reaction of the compound of the formula
~II) under the influence of the catalyst.
lo Accordingly, in the process of the present inven-
tion, an alkali compound for generating hydrogen should be
present in addition to a base acting as the dehalogenating
agent. As the alkali compound, there can be mentioned,
for example, sodium hydroxide, potassium hydroxide and
calcium hydroxide.
The ~lkali compound may be u~ed singly in a large
amount so that it also acts as the neutralizing agent for
the formed hydrohalogenic acid, but, of course, a different
base may be used as the dehydrohalogenating agent in
combination with the alkali compound.
As the base that can be used as the dehydro-
halogenating agent in combination with the alkali compound,
there can be mentioned inorganic and oryanic bases such as
potassium carbonate, sodium carbonate and sodium acetate,
and aliphatic, aromatic and hsterocyclic amines such as
triethylamine, ethylenediamine, diethylaniline and py-
ridine. Single use of an inorganic base is preferred, and
single use af an alkali metal hydroxide, particularly
sodium hydraxide, is especially advantageous from the
economical viewpoint.
In the present invention, when the alkali metal
hydroxide alone is used, hydrogen is generated by reacting
the alkali in an amount of at least two moles with the
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- .
-
.
- 7 -
stoichiometric amou~t of methanol, and consequently, in
order to give the dehalogenated product, the alkali should
be used in an amoun~ of at least 0.~6 mole per mole of the
starting c~mpound of the formula ~II), ~or example, a 3-
phenoxybenzyl 2~(4-alkoxy-3-halogenoph~nyl)-2 mPthylpropyl
ether.
When the action of the alkali as the dehydro-
halogenating agent is also intended, it is preferred that
the alkali be used in an amount of 1.0 to 10 moles per
lo mole of the compound of the formula (II), for example, a
3-phenoxybenzyl 2-(4-alkoxy-3-halogenophenyl~-2-methyl-
propyl ether.
Therefore, the amount of the alkali is preferably
1.66 to 10.7 moles per halogen atom at Yl and Y2 in the
compound of the formula (II) in a~l, gi~en by summing up
"at least 0.66 mole for hydrogen formation for dehalogenat-
ing agent" and "at least 1 mole as dehydroh~logenating
agent (neutralizing agent for the formed hydrohalogenic
acid)".
As the alcohol used as the reducing ag~nt in com-
bination with the alkali in the process of the present
invention, there can be mentioned lowsr aliphatic monools
and diols such as methanol, ethanol, isopropanol, n-pro-
panol, n-butanol, isobutanol, ethylene glycol and propylene
glycol. Monools, especially methanol, are preferred.
These alcohols may be used in the form of mixtures of two
or more of them. When an alkali metal hydroxide is used
as the alkali and a monool is used as the alcohol, it is
necessary that the alcohol should be used in an amount of
at least about 0.3 mole of the stoichiometric amount,
preferably 0.4 to 30 moles, per mole of the compound of
the formula (II), for example, a 3-phenoxybenzyl 2-(4-
alkoxy-3-halogenophenyl)-2-methylpropyl ether, and when
the alcohol is used also as the reaction medium described ;,
35 below, the amount of alcohol is appropriately selected .
- .: ',
.. .
- ~
while taking the amount of the alcohol used as the reaction
medium into consideration.
In the hydrodehalogenation step, addition of water
is not ab~olutely n~cessary. Howev~r, in order to increase
5 the reaction rate, it is prePerred that water be added and
the reaction be carried out in a water-containing organic
solvent. Various organic solvents, for example, alcohols
such as methanol, polyhydric alcohols such as ethylene
glycol, acetic acid and acetic acid esters may be used as
the organic solvent. However, it is preferred that the
same alcohol as used in the reducing reaction be used.
When the organic solvent is used, it is preferred that the
concentration be adjusted to 20 to 80%. When an alcohol
and water are used as the reaction medium, the concentra-
tion of the alcohol is selected within the above-mentioned
range while taking the amount of the alcohol used in the
reducing reaction into consideration.
The amount o~ the reaction medium used can be
selected within a broad range, but in view of the reaction
rate and the volume efficiency of the reaction vessel, it
is preferred that the reaction medium be used in an amount
of 2 to 10 parts by volume per part by volume of the
compound of the formula (II).
As the catalyst, there can be used a nickel catalyst
such as Raney nickel, a palladium catalyst such as pal-
ladium-carbon or palladium-alumina, and a platinum cata-
lyst. Palladium-carbon is especially advantageous. The
catalyst is used in an amount of 0.1 to 20% by weight,
preferably 1 to 6% by weight, based on the compound repre-
sented by the formula (II).
As the 4-alkoxyneophyl ether derivative o the
formula (I) prepared according to the process oP the
present invention, there can be mentioned 3-phenoxybenzyl
2-(4-methoxyphenyl)-2-methylpropyl ether, 3 phenoxy-4-
.,
. . . .
~z~
fluorobenzyl 2-(4-methoxyphenyl)~2-methylpropyl ether, 3-
~4-fluorophenoxy)benzyl 2-~4-methoxyphenyl)-2-methylpropyl
ether, 3-(4-fluorophenoxy)-4-fluoroben2yl 2-(4-methoxy-
phenyl)-2-methylpropyl ether, 3-phenoxybenzyl 2 (4-ethoxy-
phenyl)-2-methylpropyl ether, 3-phenoxy-4-~luorobenzyl 2-
(4-ethoxyphenyl)-2-methylpropyl ether, 3-(4-fluorophenoxy)
benzyl 2-(4-ethoxyphenyl)-2-methylpropyl ether, 3-(4-
fluorophenoxy)-4-fluorobenzyl 2-(4-ethoxyphenyl)-2-methyl-
propyl ether, 3-phenoxy-6-fluorobenzyl 2-(~-ethoxyphenyl)-
2-methylpropyl ether, 3-(2-fluorophenoxy)benzyl 2-(4-
ethoxyphenyl)-2-methylpropyl ether, 3-phenoxybenzyl 2-(4-
(i-propoxy)phenyl)-2-methylpropyl ether, 3-phenoxy-4-
fluorobenzyl 2-(4-(i-propoxy ? phenyl)-2-methylpropyl ether,
3-phenoxybenzyl 2-(4-(1-methylpropoxy)phenyl)-2-methyl-
propyl ether, 3-phenoxybenzyl 2-(4-(n-butoxy)phenyl)-2-
methylpropyl ether, 3-phenoxybenzyl 2-(4-(t-butoxy)phenyl)-
2-methylpropyl ether and 3-phenoxybenzyl 2-(4-(n-penty-
loxy)-phenyl)-~-methylpropyl ether.
A general ~mbodiment of the present invention will
now be described. The dehalogenation reaction of the
present invention may be carried out under atmospheric
pressure according to the amounts of the hydrogenation
catalyst, the alkali compound and the lower alcohol used.
However, it is generally preferred that the reaction be
carried out under an elevated pressure.
A reaction vessel is charged with predetermined
amounts of a 3-phenoxybenzyl 2-(4-alkoxy-3-halogenophenyl)-
2-methylpropyl ether or 3-phenoxybenzyl 2-(4-alkoxy-3,5-
dihalogenophenyl)-2-methylpropyl ether represented by the
general formula (II), an alcohol and alkali as the reducing
agent and a hydrogenation catalyst, and the mixture is
heated at 50 to 220C, preferably 80 to 150C, and stirred
at this temperature for 0.5 to 50 hours, preferably 3 to
30 hours. The reaction mixture is cooled to room tempera-
ture, and if necessary, in order to form a homogeneoussolution, a nonpolar solvent such as water or benzene is
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-- 10 --
added, and the catalyst is separated by filtration under
reduced pressure. The mother liquor is subjected to phase
separation, and the oil layer is washed with water and
dehydrated and the solvent is removed to give a 3-pheno~y-
benzyl 2-(4-alkoxyphenyl)-2-methylpropyl ether represented
by the general fo~nula (I) as the intended product.
The obtained product can be satisfactorily used as
such as an insecticidal and acaricidal agent, but according
to need, the product may be purified by reduced pressure
distillation, column chromatography or recrystalliæation.
The present invention will now be described in
detail more with reference to the following examples.
Example 1
An autoclave having a capacity of 500 m~ was charged
with 60.0 g (0.146 mole) of 3-phenoxybenzyl 2-(3-chloro-4-
ethoxyphenyl)-2-methylpropyl ether, 18.8g (0.47 mole~ of
flaky sodium hdyroxide, 2.4 g of 5%-palladium-carbon (50%
wet), 85.3 g (2~66 moles) of methanol and 36 g of water.
The autoclave was sealed and the inner atmosphere was
replaced by nitrogen, and the mixture was heated with
stirring at an inner temperature of 1~0C for 12 hours to
complete reaction.
The reaction was cooled to 50C and the residual
pressure as released, and 100 m~ of benzene was added into
the autoclave to dissolve the oil layer. Then, the cata-
lyst was removed by filtration, and the filtrate was
allowed to stand still to cause phase separation, and the
benzene layer was recovered and washed with 120 m~ of
water three times, and benzene was removed by distillation
under reduced pressure to give an oily product. From the
results of the analysis of the oily product by gas chroma-
tography according to the internal standard method, it
was found that the oily product comprised 98.8~ of 3-
phenoxybenæyl 2-(4-ethoxyphenyl)-2-methylpropyl ether and
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-- 11 ~
0.3~ of unreac~ed starting 3-phenoxybenzyl 2-(3-chloro-4-
ethoxyphenyl)-2-methylpropyl ether, and that the content
of aach of 3-phenoxytoluene and 4-ethoxyneophyl alcohol
formed by cleaving of the ether linkage was lower than
0.3%. The amount of the obtained oil product was 53.8 g,
and the yield was 96.7%.
Example 2
An autoclave having a capacity of 300 m~ was charged
with 60.0 g (0.140 mole) of 3-phenoxy-4-*luorobenzyl 2-(3-
lo chloro-4-ethoxyphenyl)-2-methylpropyl ether, 18.8 g (0.47
mole) of flaXy sodium hydroxide, 2.4 g of 5~-palladium
carbon (50% wet), 56.9 g (1.77 moles) of methanol and
54.0 g of water~ The autoclave was sealed and the inner
atmosphere was replaced by nitrogen, and the mixutre was
heated with stirring at an inner temperature of 120C for
10 hours to complete reaction.
The reaction mixture was cooled to room temperature
and the residual pressure was released, and 100 m~ of
benzene was added into the autoclave to dissolve the oily
portion. Then, the catalyst was removed by filtration,
and the filtrate was sufficiently shaken and allowed to
stand still to cause phase separation. Then, the obtained
benzene la~er was washed with 100 m~ of water three times
and benzene was removed by distillation under reduced
pressure to give an oily product. From the results of the
analysis of the oily product by gas chromatography accord-
ing to the internal standard method, it was found that the
oily product comprises 98.2% of 3-phenoxy-4-fluorobenzyl
2-(4-ethoxyphenyl)-2-methylpropyl ether and 0.7% of start-
ing 3 phenoxy-4-fluorobenzyl 2-(3-chloro-4-ethoxyphenyl)-
2-methylpropyl ether, and that the content of each of 3-
phenoxy-4-fluorotoluene and 4-ethoxyneophyl alcohol formed
by cleaving of the ether linkage was lower than 0.2%.
Moreover, 0.8% of 3-phenoxybenzyl 2-(4-ethoxyphenyl)-2-
methylpropyl ether presumed to have been formed by reduc-
tion of the fluorine atom was contained.
.. .. .
: ' - , .
The amount of the obtained oily product was 54.0 g
and the yield was 96.0%.
Example 3
A four-necked glass ~lask having a capacity of 300
m~ was charged with 60.0 g (0.146 mole) of 3-phenoxybenzyl
2-(3-chloro-4-ethoxyphenyl)-2-methylpropyl ether, 18.8 g
(0.47 mole) of flaky sodium hydroxide, 4.8 g of 5%-pal-
ladium-carbon (50~ wet), 86.2 g (1.87 moles) of ethanol
and 36 g of water, and the mixture was heated with stirring
at the boiling point (81C) for 6 hours to complete reac-
tion.
The reaction mixture was cooled to 50C, and 50 m~
of benzene was added into the reaction vessel to dissolve
the oily portion. The catalyst was removed by filtration
and the *iltrate was allowed to stand still to cause phase
separation. The benzene layer was recovered and washed
with 100 m~ of water three times. Benzene was removed by
distilla~ionn under reduced pressure to give an oil pro-
duct.
From the results of the analysis of the oily productby gas chromatography according to the internal standard
method, it was found that the oily product comprises 96.2%
of 3-phenoxybenzyl 2-(4-ethoxyphenyl)-2-methylpropyl ether
and 1.5% of unreacted starting 3-phenoxybenzyl 2-(3-chloro-
4-ethoxyphenyl)-2-methylpropyl ether, and that the oily
product contained 0~5% of 3-phenoxytoluene and 0.2% of 4-
ethoxyneophyl alcohol, each being formed by cleaving of
the ether linkage. The amount of the obtained oily product
was 54.0 g and the yield was 94.5~.
Example 4
A four-necked glass flask having a capacity of
300 m~ was charged with 60.0 g (0.146 mole) of 3-phenoxy-
benzyl 2 (3-chloro-4-ethoxyphenyl)-2-methylpropyl ether,
: .
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79~
- 13 -
23.5 g (0.588 mole) of flaky sodium hydroxide, 4.8 g of
5%-palladium-carbon (50% wet), 18 g (0.290 mole) of ethy-
lene glycol and 144 g of w~ter, and the mixture was heated
with stirring at the boiliny point (104C) for 12 hours to
complete reaction.
The reaction mixture was cooled to 50C and 50 m
of benzene was added into the reaction vessel to dissolve
the oily portion. The catalyst was removed by filtration
and the filtrate was allowed to stand still to cause phase
separation. The benzene layer was washed with 100 m~ of
water three times. Benzene was removed by distillation
under reduced pressure to give an oily product.
From the results of the analysis of the oily product
by gas chromatography according to the internal standard
method, it was found that the oily product comprised 95.3~
of 3-phenoxybenzyl 2~ ethoxyphenyl~-2-methylpropyl ether
and 2.2% of unreacted starting 3-phenoxybenzyl 2-(3-chloro-
4-ethoxyphanyl)-2-methy~propyl ether, and that the oily
product contained 0.6% of 3-phenoxytoluene and 0.4% of 4-
ethoxyneophyl alcohol, each being formed by cleaving ofthe ether linkage. The amount of the obtained oily product
was 54.3 g and the yield was 94.1%.
Referential~Exa~ple
An autoclave having a capacity of 500 m~ was charged
with 60.0 g (0.146 mole) of 3-phenoxybenzyl 2-(3-chloro-4-
ethoxyphenyl)-2-methylpropyl ether, 7.5 g (0.188 mole) of
flaky sodium hydroxide, 7.2 g of 5~-palladium-carbon (50%
wet), 83.5 g of methanol and 36 m~ of water, and the
autoclave was sealed and the inner atmosphere was replaced
by nitrogen. Hydrogen was filled in the autoclave so that
the pressure was 8 kg/cm2G. The mixture was heated with
stirring at an inner temperature of 110C for 12 hours
while supplying hydrogen so that the pressure was 8 to
10 kg~cm2G, to complete reaction.
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The reaction mixture was cooled to room temperature
and the residual pressure was released, and 120 m~ of
benzene was added into the autoclave to dissolve the oily
layer. Then, the insoluble substance was removed by
filtration, and the mother liquid was washe~ with 30 mC of
benzene, sufficiently shaken and allowed to stand still to
cause phase separation and give a benzene layer. The
benzene layer was washed with 120 m of water three times
and benzene was removed by distillation under pressure to
give an oily product. From the results of the analysis of
the oily product by gas chromatography according to the
internal standard method, it was found that the oily
product comprised 98.5% of 3-phenoxybenzyl 2-(4-ethoxy-
phenyl~-2-methylpropyl ether and 0.5% of unreacted starting
3-phenoxybenzyl 2-(3-chloro-4-ethoxyphenyl)-2-methylpropyl
ether, and that the content of each of 3-phenoxytoluene
and 4-ethoxyneophyl alcohol formed by cleaving of the
ether linkage was lower than 0.3%. The amount of the
obtained oily product was 53.6 g and the yield was 96.0%.
Example 5
An autoclave having a capacity of 300 m~ was charged
with 30.0 g (0.066 mole) of 3-phenoxybenzyl 2-(3-bromo-4-
ethoxyphenyl)-2-methylpropyl ether, 8.5 g of flaky sodium
hydroxide, 0.9 g of 5%-palladium-carbon (50% wet), 42.7 g
(2.3 moles) of methanol and 18 g of water, and the autoc-
lave was sealed and the inner atmosphere was replaced by
nitrogen. The mixture was heated with stirring at an
inner temperature of 110C for 10 hours to complete reac-
tion.
The xeaction mixture was cooled to 50C and the
residual pressure was released, and 70 m~ of benzene was
added into the autoclave to dissolve the oil layer. The
catalyst was removed by filtration, and the filtrate was
allowed to stand still to cause phase separation to give a
~ 35 benzene layer. Then, the benzene layer was washed with
y~ lO0 m~ of water three times, and benzene was removed by
-, -
. . : . ............ . .
.
- 15 -
distillation under reduced pressure to yive an oily pro-
duct. ~rom the results of the analysis of the oily product
by gas chromatography according to the internal standard
method, it was found that the oily product comprised 98.6%
of 3-phenoxybenzyl 2-(4-ethoxyphenyl~-2-methylpropyl ether
and 0.~% of unreacted ~tarting 3-phenoxybenzyl 2-~3-bromo-
4-ethoxyphenyl)-2-methylpropyl ether, and that the content
of each of 3-phenoxytoluene and 4-ethoxyneophyl alcohol
formed by cleaving of the ether linkage was lower than
0.3%. The amount of the obtained oily product was 23.8 g
and the yield was 94.4%.
Example 6
An autoclave having a capacity of 300 m~ was charged
with 40.0 g (0.072 mole) of 3-phenoxybenzyl 2-(3-iodo-4-
ethoxyphenyl)-2-methylpropyl ether, 9.3 g (0.23 mole) of
flaky sodium hydroxide, 1~2 g of 5%-palladium carbon (50
wet), 64.0 g (2.0 moles) of methanol and 27 g of water,
and the autoclave was sealed and the inner atmosphere was
replaced by nitrogen. The mixture was heated with stirring
at ~n inner temperature of 110C ~or 10 hours to complete
reaction.
An oily product was obtained by carrying out the
post-treatment in the same manner as in Example 5. From
the results of the analysis of the oily product by gas
chromatography according to the internal standard method,
it was found that the oily product comprises 99.2% of 3-
phenoxybenzyl 2-(4-ethoxyphenyl~-2-methylpropyl ether and
0.1% of unreacted starting 3-phenoxybenzyl 2-(3-iodo-4-
ethoxyphenyl)-2-methylpropyl ether, and that the content of
each of 3-phenoxytoluene and 4-ethoxyneophyl alcohol formed
by cleaving of the ether linkage was lower than 0.3~. The
amount of the obtained oily product was 26.0 g and the
yield was 95.1%.
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- 16 -
Example ?
The dechlorination reaction was carried out in the
same manner as in Example 1 except that 1.44 g of 1~%-
palladium-alumina (100% dry) was used instead of the 5%-
palladium-carbon used as the hydrogena$ion catalyst in
Example l, and an oily product was o~tained by carrying
out the post-treatment in th~ same manner as in Example 1.
From the results of the analysis of the oily product by
gas chromatography according to the internal standard
method, it was found that the oily product comprised 97~4%
of 3-phenoxybenzyl 2-~4-ethoxyphenyl)-2-methylpropyl ether
and 0.5~ of unreacted starting 3-phenoxybenzyl 2-(3-chloro-
4-ethoxyphenyl)-2-methylpropyl ether, and that the content
of each of 3-phenoxytoluene and 4-ethoxyneophyl alcohol
formed by ~leaving of the ether linkage was lower than
0.7%. The amount of ~he obtained oily product was 52.0 g
and the yield was 93.2~.
Comparati~e Example
An autoclave having a capacity of 300 m~ was charged
with 60.0 g (0.145 mole~ of 3-phenoxybenzyl 2-(3-chloro-4-
ethoxyphenyl)-2~methylpropyl ether, 29.8 g (0.438 mole) of
sodium formate, 4.8 g of 5~-palladium-carbon (50% wet) and
144 m~ of water, and the mixture was heated with stirring
at an inner temperature of 110 G C for 12 hours to complete
25 reaction.
The reaction mixture was cooled to room temperature,
and 100 m~ of benzene was added into the reaction vessel
to dissol~e the oily portion. Then, the catalyst was
removed by filtration and the filtrate was allowed to
~0 stand still to cause phase separation to obtain a benzene
layer. The benzene layer was washed with 100 m~ of water
three times, and benzene was removed by distillation under
reduced pressure to give an oil product. From the results
of the analysis of the oily product by gas chromatography
35 according to the internal standard method, it was found
r that the oil product comprised 65.8% of 3-phenoxybenzyl 2-
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- 17 -
(4-ethoxyphenyl)-2-methylpropyl ether, 21.~ of unreacted
starting 3-phenoxybenzyl 2-(3-chloro-4-ethoxyphenyl)-2-
methylpropyl ether, and 4.4% of 3-phenoxytoluene and 2.9%
of 4-ethoxyneophyl alcohol as by-products formed by cleav-
ing of the ether linkage. The amount of the obtained oilyproduct was 57.4 g and the yield was 68.7%.
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