US Pat 4,638,094

PROCESS FOR PRODUCING PHENYLACETONES

A phenylacetone or its derivative having the general formula (A
phenylacetone having zero to three substituents on the ring) is produced at
a high yield and a high selectivity by reacting a 3-phenylpropylene or its
derivative having the general formula (An allylbenzene having zero to three
substituents on the ring) with an alkyl nitrite having the general formula
(RONO) wherein R is an aliphatic, aromatic, or alicyclic saturated or
unsaturated hydrocarbon group in the presence of (a) water, (b) an alcohol,
(c) a palladium catalyst, and (d) an optional amine or copper compound, or
by reacting the above-mentioned 3-phenylpropylene or its derivative with
the above-mentioned alkyl nitrite in the presence of (a) an alcohol, (b) a
palladium catalyst and (c) an optional amine or copper compound to form
1-phenyl- 2,2-dialkoxypropane or it derivative having the general formula
(A phenylalkoxypropane with zero to three substituents on the ring),
followed by hydrolyzing the reaction product.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a process for producing a phenylacetone or
its derivative.

2. Description of the Prior Art

Phenylacetone and its derivatives ("phenylacetones" hereinbelow) are useful
as intermediates for various agricultural chemicals and pharmaceutical
preparations. For example, 4-hydroxy-3-methoxyphenylacetone (HMPA), 3,4-
dimethoxyphenylacetone (DMPA), and 3,4-methylenedioxyphenylacetone are
utilized as intermediates for producing L-alpha-methyldopa, which is used
as antihypertensive. Thus, the phenylacetones are practically useful
compounds. However, industrially satisfactory processes for producing
phenylacetones have not yet been developed. For instance, British Patent
Specification No. 1119612 discloses a process for producing DMPA by
reacting 1-(3,4- dimethoxyphenyl)propylene with peroxides such as peracetic
acid, followed by treating the resultant diol type products with acidic
substances such as zinc chloride. However, this process is not entirely
satisfactory in industrial use because the yield of the treatment step with
an acidic substance is low and that the special caution should be taken in
the handling of the peroxides because of their explosive properties.

Furthermore, the Journal of the American Chemical Society (JACS) 77, 700
(1955) discloses a process for producing DMPA by reacting
3,4-dimethoxyphenyl acetonitrile with sodium ethoxide in a solvent such as
ethyl acetate to form the acetylated product, followed by hydrolysis.
However, this process includes problems that water should be completely
removed from the reaction system, which sodium ethoxide is used, in order
to prevent hydrolysis of the sodium ethoxide) that the yield of the desired
product in the hydrolysis step is low, and that the large number of steps
in the entire process is required taking into account the steps necessary
to prepare the starting 3,4-dimethoxyphenyl acetonitrile from a readily
available chemical raw material.

SUMMARY OF THE INVENTION

Accordingly, an object of the present invention is to eliminate the
above-mentioned problems and to provide a process for producing
phenylacetones from readily available starting materials at a high yield.
Another object of the present invention is to provide a process for
producing phenylacetone at a high reaction rate without using severe
reaction conditions.

Other objects and advantages of the present invention will be apparent from
the description set forth hereinbelow. In accordance with the present
invention, there is provided a process for producing a phenylacetone or its
derivative having the general formula (a phenylacetone having zero to three
substituents on the ring) is produced at a high yield and a high
selectivity by reacting a 3-phenylpropylene or its derivative having the
general formula (an allylbenzene having zero to three substituents on the
ring) with an alkyl nitrite having the general formula (RONO) wherein R is
an aliphatic, aromatic, or alicyclic saturated or unsaturated hydrocarbon
group in the presence of (a) water, (b) an alcohol, (c) a palladium
catalyst, and (d) an optional amine or copper compound, or by reacting the
above-mentioned 3-phenylpropylene or its derivative with the
above-mentioned alkyl nitrite in the presence of (a) an alcohol, (b) a
palladium catalyst and (c) an optional amine or copper compound to form
1-phenyl-2,2-dialkoxypropane or it derivative having the general formula (a
phenylalkoxypropane with zero to three substituents on the ring), followed
by hydrolyzing the reaction product.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The 3-phenylpropylene and its derivatives ("3-phenylpropylenes"
hereinbelow) usable as a starting material in the present invention are
those having the general formula (an allylbenzene having zero to three
substituents on the ring). The 3-phenylpropylenes can be readily obtained
either by extracting them from natural vegetable oils or by reacting the
corresponding benzene or substituted benzene compounds widh allyl halides
(e.g., CH2=CH-CH2Br). The alkyl nitrites usable as another starting
material in the present invention are those having the general formula
(RONO),  where R is an aliphatic, aromatic, or alicyclic saturated or
unsaturated hydrocarbon group, desirably an alkyl group having 1 to 10
carbon atoms such as methyl, ethyl propyl, butyl, pentyl, hexyl, heptyl,
octyl, nonyl, and decyl, or a benzyl group. Saturated aliphatic alkyl
groups having 1 to 4 carbon atoms such as methyl, ethyl n-propyl,
isopropyl, n-butyl, i-butyL and secbutyl are especially desirable as R in
the above-mentioned general formula. Although the amount of the alkyl
nitrites used in the present reaction may vary over a wide range, the molar
ratio of the alkyl nitrites based on 1 mole of the 3-phenylpropylene is
generally 2 moles or more, desirably 2 to 5 moles and more desirably 2.1 to
3.5 moles.

According to the first aspect of the present invention the
3-phenylpropylene and the alkyl nitrites are reacted in the presence of
water, alcohol, and palladium catalyst and, further, optionally amines or
copper compounds. The water is generally introduced into the reaction
system in an amount of 1 to 300 moles, desirably 10 to 100 moles, based on
1 mole of the starting 3-phenylpropylenes. The use of a too small amount of
the water decreases the yield of the desired phenylacetones. On the other
hand, the use of a too large amount of the water does not further improve
the reaction and necessitates a troublesome alcohol recovery treatment
after the completion of the reaction.

The effects of the alkyl nitrites and water during the reaction are not
clearly understood, but it would seem that, without prejudice to the
invention, the 3-phenylpropylene and the alkyl nitrites form
2-phenyl-2,2-dialkoxypropanes, which are in turn hydrolyzed with water to
form the desired phenylacetones. The basic reaction of the first aspect of
the present invention is as follows: The above-mentioned reaction (A)
desirably proceeds in the presence of an alcohol and a palladium catalyst,
and optionally, an amine and a copper coms pound.

Typical examples of the alcohols usable in the present invention are
alcohols having 1 to 10 carbon atoms such as methyl alcohol, ethyl alcohol,
propyl alcohol, butyl alcohol pentyl alcohol, hexyl alcohol, heptyl
alcohol, octyl alcohol nonyl alcohol, decyl alcohol, and benzyl alcohol.
The alcohols ROH having the same alkyl group R as the alkyl nitrites used
in the reaction can be desirably used in the present reaction for the
reason that the alcohol contained in the reaction mixture can be readily
recovered and reused. The alcohols are desirably used in an amount of 0.5
to 10 liters based on 1 mole of the 3-phenylpropylene used. Hydrous
alcohols can be used in the present invention.
The alcohols can also serve as a solvent in the present reaction. However,
other inert solvents can be used in the present reaction. Typical examples
of the solvents are esters of lower fatty acids such as ethyl acetate and
butyl acetate, ethers such as dioxane, dibutyl ether, and tetrahydrofuran,
aromatic hydrocarbons such as benzene, toluene and xylene, alicyclic
hydrocarbons such as cyclohexane, and aliphatic hydrocarbons such as
n-hexane. The palladium catalysts usable in the present invention include
palladium salts and palladium complexes. Typical examples of the palladium
nits usable as a catalyst in the present invention are palladium chloride,
palladium bromide, palladium iodide, palladium acetate, palladium sulfate,
and palladium nitrate, desirably palladium halides such as palladium
chloride and palladium bromide. Typical examples of the palladium complexes
are dimers of dichloroethylene palladium (II), dimers of dibromoethylene
palladium (II), dimers of dichloropropylene palladium (II), bis
(acetonitrile) palladium (II) chloride, bis (acetonitrile) palladium (II)
bromide, bis (benzonitrile) palladium (II) chloride, bis (benzonitrile
palladium (II) bromide, bis (dimethylsulfoxide) palladium (II) chloride,
bis (N,N- dimethylformamide) palladium (lI) chloride, bis
(N,N'-dimethylacetoamide) palladium (II) chloride, tetrakis (acetonitrile)
palladium (II) tetrafluoroborate, tetrakis (acetonitrile) palladiun (II)
perchlorate, bis (acetylacetonate) palladium (II) sodium tetrachloro
palladate (II), lithium tetrabromopalladate (II), lithium bis (oxalato)
palladate (II), and sodium tetranitropalladate (lI).

The palladium catalysts are desirably used in al amount of 0.001 to 0.2
mole, more desirably 0.005 to 0.1 mole, based on 1 mole of the starting
3-phenyipropylenes. The use of a too small amount of the palladium catalyst
does not proceed the desired reaction at a sufficient reaction rate.
Contrary to this, the use of a too large amount of the palladium catalyst
fails to improve the reaction rate of the desired reaction, the recovery
operation of the catalyst becomes troublesome and the loss of the palladium
catalyst during the catalyst recovery undesirably increases. According to
the preferred embodiment of the present invention, the production amount of
the desired products obtained per unit weight of the palladium catalysts
can be further increased in the presence of amines or copper compounds in
the reaction system Thus, the amount of the expensive palladium catalyst to
be used can be reduced.

Typical examples of the amines optionally usable as co-catalyst are those
having the general formula (NR1R2R3), wherein R1, R2, and R3 are the same
or different and represent a hydrogen atom and a lower alkyl group having 1
to 6 carbon atoms and two groups of R1, R2 and R3 may be alkylene groups,
which combine together to form a ring. Typical examples of the amines
usable in the present invention are tertiary amines such as trimethylamine
triethylamine, tripropylamine, tributylamine, tripentylamine, and
trihexylamine; secondary amines such at dimethylamine, diethylamine,
dipropylamine, dibutylamine, dipentylamine and dihexylamine; primary amines
such as methylamine , ethylamine , propylamine, butylamine, pentylamine ,
and hexylamine ; cyclic amines such as piperidine, N-methylpiperidine,
N-ethyl piperidine, N-propylpiperidine, N-butylpiperidine, N
pentylpiperidine, N- hexylpiperidine, pyrrolidine, N-methylpyrroli dine,
N-ethylpyrrolidine, N-propylpyrrolidine, N-pentylpyrrolidine, and N-
hexylpyrrolidine.

These amines can be used in an amount of 0.1 to 2 moles, desirably 0.2 to 1
mole, based on 1 mole of the palladium catalyst. The use of a too small
amount of the amines fails to result in the desired co-catalytic effects
Contrary to this, the use of a too large amount of the amines does not
result in the further improvement in the desired effects and rather
increases the loss of the amines during the recovery thereof. Typical
examples of the copper compounds optionally usable as a co-catalyst in the
present invention art copper halides, copper sulfates, copper nitrates,
copper hydroxides, and copper oxides. Of these copper compounds, copper
halides such as cuprous chloride, cupric chloride, cuprous bromide, and
cupric bromide are especially desirable. When the copper compounds other
than the copper halides are used, it is desirable to use about 0.1 to 5
moles of a hydrogen halide acid, based on 1 mole of the copper compound,
together with the copper compounds. The copper compounds can be used in an
amount of 1 to 30 moles, desirably 3 to 10 moles, based on 1 mole of the
palladium catalysts. The use of a too small amount of the copper compounds
does not result in the further improvement in the desired effects and
rather, complicate the separation and recovery of the catalysts. The most
practically desirable combinations of the palladium catalysts and the
copper compounds are PdCl2-CuCl and PdCl2-CuCl2 from the standpoint of the
availability and economical factor thereof.

The present reaction can be desirably carried out at a temperature of 0ø C.
to 150ø C., desirably 10ø C. to 90ø C. The use of a too high reaction
temperature tends to cause undesirable side reactions such as an
isomerization reaction, whereas the use of a too low reaction temperature
is not practical because of the low reaction rate. The reaction time is
desirably 10 minutes to 5 hours, although this depends upon the reaction
conditions. The reaction pressure of the reaction system during the
reaction can be an atmospheric pressure to about 200 kg/cm2, although there
is no specific limitation in the reaction pressure.

The present process can be carried out as follows: For example, the
starting 3-phenylpropylenes, water, the alcohols, and the palladium
catalysts and the optional amines or copper compounds are charged into a
reaction vessel. Then, the alkyl nitrites are added to the mixture, causing
it to react under the predetermined reaction conditions. It should be
noted, however, that the addition order of the reactants and catalysts is
not specifically limited.

After completion of the reaction, the resultant NO gas, the unreacted
starting materials, water, alcohol, the desired product (i.e.,
phenylacetones), the optional amines and copper compounds are distilled
under a reduced pressure and recovered separately.

The recovered unreacted starting materials and alcohols (which may contain
water) and the optional amines and copper compounds can be circulatedly
utilized. Furthermore, the NO gas can be used in the production of the
alkyl nitrites.

According to the second aspect of the present invention, the
3-phenylpropylene and the alkyl nitrites are reacted in the presence of the
alcohols and the palladium catalysts and, further, optionally the amines or
copper compounds to form 1-phenyl-2,2-dialkoxypropane or its derivatives as
an intermediate, followed by hydrolysis of the reaction product.

The basic reactions of the second aspect of the present invention proceed
as follows:

The above-mentioned reaction (B) desirably proceeds in the presence of the
above-mentioned alcohols and the.above- mentioned palladium catalysts and,
optionally, the above-mentioned amines or copper compounds. This reaction
can be carried out at a temperature of 0ø C. to 150ø C., desirably 10ø C.
to 90ø C. optionally in the presence of the above-mentioned inert solvents.
The use of a too high reaction temperature tends to cause undesirable side
reactions such as an isomerization reaction, whereas the use of a too low
temperature is not practical due to the low reaction rate. The pressure
within the reaction system during reaction can be an atmospheric pressure
to about 200 kg/cm2. The reaction time is desirably 10 minutes to 5 hours,
although this depends upon the reaction conditions. The present reaction
{B) can be carried out as follows; For example, the starting
3-phenylpropylenes, the alcohols, the palladium catalysts and the optional
amines or copper compounds are charged into a reaction vessel. The alkyl
nitrites are added to the mixture, causing it to react under the
predetermined reaction conditions. It should be noted, however, that the
addition order of the above-mentioned reactants and catalysts is not
specifically limited. After completion of the reaction, the resultant NO
gas, the unreacted starting materials, alcohol, the desired intermediate
(i.e., 1-phenyl-2,2-dialkoxypropanes), the optional amines and copper
compounds are distilled under a reduced pressure and recovered.

The recovered unreacted starting materials and alcohols as well as the
optional amines and copper compounds can be again used. Further, NO gas can
be used in the production of the alkyl nitrites. The 1-phenyl-2,2-dialkoxy-
propanes thus obtained are hydrolyzed in the presence of water as shown in
the above- mentioned reaction (C) either after separating it, or without
separating it from the reaction mixture. The amount of water used in the
hydrolysis is stoichiometrically 1 mole based on 1 mol of the starting
1-phenyl-2,2 dialkoxypropanes, but is desirably 3 to 500 moles based on I
mol of the starting 1-phenyl-2,2-dialkoxypropanes. In the case where the
amount of the water present in the reaction system is small, the use of
solvents other than water is desirable. Even in the case where a large
amount of water is used, the use of solvents other than water is also
desirable in view of the fact that the starting 1-phenyl-2,2-dialkoxy-
propanes are not readily soluble in water. The solvents suitable for use in
the hydrolysis of 1-phenyl-2,2-dialkoxypropanes are those which dissolved
well both the 1-phenyl-2,2-dialkoxypropanes and the water and also which
are substantially inert against the hydrolysis. Typical examples of these
solvents are lower alcohols such as methanol, ethanol, propanol; and
butanol; ethers such as dioxane and tetrahydrofuran; and carboxylic acids
such as acetic acid and propionic acid. Of these examples, the use of
methanol, ethanol, propanol, butanol, dioxane, and tetrahydrofuran are
particularly desirable. Furthermore, slightly water-soluble alcohols such
as pentanol, hexanol, and heptanol can be used as a solvent in combination
with dioxane and tetrabydrofuran.

These solvents can be desirably used in an amount of about 0.5 to about 10
liters per 1 mole of 1-phenyl- 2,2-dialkoxypropanes.

The hydrolysis can be desirably carried out under a neutral or acidic
condition rather than under basic conditions, since the reaction rate of
the hydrolysis is low under under basic conditions. Optionally, the pH of
the reaction mixture can be adjusted to 4 to 7 by adding a mineral acid
such as hydrochloric acid or sulfuric acid. The hydrolysis is generally
completed at a temperature of about 0ø C. to about 80ø C. for about 5
minutes to about 90 minutes. The resultant phenylacetones can be isolated
from the reaction mixture by any conventional separation technique such as
distillation or extraction.

EXAMPLES

The present invention will now be further illustrated by, but is by no
means limited to, the following Exarnples. In the following examples, the
conversion of the starting materials, the yields of the desired
intermediates or products, and the Pd turn-over number are calculated as
follows:

                      Formed molar quantity of product
Pd Turnover Number = ----------------------------------
                     Charged molar quantity of catalyst

Example 1

A 0.10 mole amount of the starting 3-phenylpropylene, 0.25 mole of methyl
nitrite, 0.5 liter of methyl alcohol, 36 g of water, and 0.008 mole (1.42
g) of a palladium chloride catalyst were charged into a reaction vessel.
Then, the reaction was carried out at a temperature of 25øC. for 2 hours.
After completion of the reaction, the reaction mixture was gas
chromatographically analyzed to quantitatively determine the amounts of the
unreacted starting material and the resultant desired products As a result,
the conversion of the starting material was 100% and the yield of the
desired product (phenylacetone) was 90%.

Example 2

Phenylacetone was prepared in the same manner as in Example 1, except that
n-butyl nitrite and n-butyl alcohol were used in lieu of methyl nitrite and
methyl alcohol and that the reaction temperature was changed to 55ø C.
After completion of the reaction, the unreacted starting material and the
desired product were quantitatively analyzed as in Example 1. The
conversion of the starting material was 100% and the yield of the desired
product was 87%.

Example 24

3,4-methylenedioxyphenylacetone was prepared in the same manner as in
example 1, except that 3-(3,4-methylenedioxyphenyl)propylene and the same
amount (0.008 mole) of palladium bromide were used in lieu of 3-phenyl-
propylene and the palladium chloride, respectively. Conversion 100%, yield
95%.

Example 39
        
A 0.10 mole amount of the starting 3-phenylpropylene, 0.25 mole of 
methyl nitrite, 0.5 liter of methyl alcohol, 36 g of water, 0.00025 mole 
of trimethylamine, and 0.0005 mole of a palladium chloride catalyst were 
charged into a reaction vessel. Then, the reaction was carried out at a 
temperature of 20.degree. C. for 1.5 hours.
        
After completion of the reaction, the reaction mixture was gas 
chromatographically analyzed to quantitatively determine the amounts of 
the unreacted starting material and the resultant desired product. As a 
result, the conversion of the starting material was 92%, the yield of 
the desired product (phenylacetone) was 80%, and the Pd turn-over number 
was 160.

Example 51
        
3,4-Methylenedioxyphenylacetone was prepared in the same manner as in 
Example 39, except that 3-(3,4-methylenedioxyphenyl) propylene was used 
in lieu of 3-phenylpropylene.
        
After completion of the reaction, the unreacted starting material and 
the desired product were quantitatively analyzed as in Example 39. The 
conversion of the starting material was 92%, the yield of the desired 
product was 83%, and the Pd turn-over number was 166.

Example 65
        
A 0.10 mole amount of the starting 3-(3,4-dimethoxyphenyl) propylene, 
0.25 mole of methyl nitrite, 0.5 liter of methyl alcohol, 36 g of water, 
and 0.003 mole (corresponding to 0.006 mole of palladium atom) of the 
dimer of dichloroethylene palladium (II) catalyst were charged into a 
reaction vessel. Then, the reaction was carried out at a temperature of 
20.degree. C. for 1.5 hours.
        
After completion of the reaction, the reaction mixture was gas 
chromatographically analyzed to quantitatively determine the amounts of 
the unreacted starting material and the resultant desired product. As a 
result, the conversion of the starting material was 100% and the yield 
of the desired product (3,4-dimethoxyphenylacetone) was 90%.

Example 68
        
3,4-Methylenedioxyphenylacetone was prepared in the same manner as in 
Example 65, except that 0.10 mole of 3-(3,4-methylenedioxyphenyl) 
propylene was used as a starting material and 0.006 mole of bis 
(benzonitrile) palladium (II) chloride was used as a catalyst.
        
After completion of the reaction, the unreacted starting material and 
the desired product were quantitatively analyzed as in Example 65. The 
conversion of the starting material was 100% and the yield of the 
desired product was 88%.
        
Example 70
        
A 0.10 mole amount of the starting 3-phenylpropylene, 0.25 mole of 
methyl nitrite, 0.5 liter of methyl alcohol, 36 g of water, 0.0005 mole 
of a palladium chloride catalyst, and 0.0025 mole of cuprous chloride 
were charged were charged into a reaction vessel. Then, the reaction was 
carried out at a temperature of 20.degree. C. for 1.5 hours.
        
After completion of the reaction, the reaction mixture was gas 
chromatographically analyzed to quantitatively determine the amounts of 
the unreacted starting material and the resultant desired product. As a 
result, the conversion of the starting material was 94%, the yield of 
the desired product was 83%, and the Pd turn-over number was 166.
        
Examples 71 to 76
        
The reaction of Example 70 was repeated, except that 0.10 mole of each 
of various 3-phenylpropylenes listed in Table 10 was used as a starting 
material and 0.0025 mole of CuCl.sub.2 or CuCl was used as a copper 
compound.
        
The results are shown in Table 10.
        
                                  TABLE 10

No. 3-phenylpropylenes   phenylacetones   Conv. Cu Salt Yield  Pd turn-over
 
75  3-(3,4-MDP)propylene MDP2P            93%   CuCl2   84 %   168


Examples 77 to 79
        
A 0.10 mole amount of the starting 3-phenylpropylene listed in Table 11, 
0.25 mole of n-butyl nitrite, 0.5 liter of n-butyl alcohol, 36 g of 
water, 0.0025 mole of CuCl.sub.2 as a copper compound and 0.0005 mole of 
a palladium chloride catalyst were charged into a reaction vessel. The 
reaction was carried out at a temperature of 60.degree. C. for 1.5 
hours.
        
After completion of the reaction, the unreacted starting material and 
the desired product were quantitatively analyzed and the Pd turn-over 
number was calculated in the same manner as in Example 70.
        
The results are shown in Table 11.
        
                                  TABLE 11

No. 3-phenylpropylenes   phenylacetones  Conv. Cu Salt  Yield  Pd turn-over
 
79  3-(3,4-MDP)propylene MDP2P           65%   CuCl2    56 %   112
   

Example 86
        
A 0.10 mole amount of the starting 3-(4-hydroxyphenyl) propylene, 0.25 
mole of methyl nitrite, 0.5 liter of methyl alcohol, and 0.006 mole of a 
palladium chloride catalyst were charged into a reaction vessel. Then, 
the reaction was carried out at a temperature of 20.degree. C. for 1.5 
hours.
        
After the completion of the reaction, the reaction mixture was gas 
chromatographically analyzed to quantitatively determine the unreacted 
starting material and the resultant intermediate product 
(1-(4-hydroxyphenyl)-2,2-dimethoxypropane). As a result, the conversion 
of the starting material was 100% and the yield of the intermediate 
product was 85%.
        
The reaction mixture (containing the intermediate product) obtained 
above was hydrolyzed at a temperature of 20.degree. C. for 60 minutes by 
adding 36 g of water.
        
After completion of the hydrolysis, the desired 4-hydroxyphenylacetone 
was quantitatively determined by a gas chromatographical analysis. The 
yield of the desired product was 84%.
        

Example 94
        
The reaction of Example 86 was repeated, except that 3-(4-methoxyphenyl) 
propylene was used in lieu of 3-(4-hydroxyphenyl) propylene and the 
hydrolysis time was changed to 30 minutes.
        
As a result, the conversion of the starting material was 100%, the yield 
of the intermediate 1-(4-methoxyphenyl)-2,2-dimethoxypropane was 94%, 
and the yield of the desired 4-methoxyphenylacetone was 93%.
        
Example 95
        
The reaction of Example 94 was repeated, except that 3-(3,4-methylenedioxy-
phenyl) propylene was used in lieu of 3-(4-methoxyphenyl) propylene.
        
As a result, the conversion of the starting material was 100%, the yield 
of the intermediate 1-(3,4-methylenedioxyphenyl)-2,2-dimethoxypropane 
was 92%, and the yield of the desired 3,4-methylenedioxyphenylacetone 
was 91%.

        
Example 133
        
A 0.10 mole amount of the starting 3-phenylpropylene, 0.25 mole of 
methyl nitrite, 0.5 liter of methyl alcohol, 0.00025 mole of 
trimethylamine, and 0.0005 mole of a palladium chloride catalyst were 
charged into a reaction vessel. Then, the reaction was carried out at a 
temperature of 20.degree. C. for 1.5 hours.
        
After completion of the reaction, the reaction mixture was gas 
chromatographically analyzed to quantitatively determine the unreacted 
starting material and the resultant intermediate product 
(1-phenyl-2,2-dimethoxypropane). As a result, the conversion of the 
starting material was 95%, the yield of the intermediate product was 85% 
and the Pd turn-over number was 170.
        
The reaction mixture (containing the intermediate product) obtained 
above was hydrolyzed at a temperature of 50.degree. C. for 60 minutes by 
adding 36 g of water thereto.
        
After the completion of the hydrolysis, the desired phenylacetone was 
quantitatively determined by a gas chromatographical analysis. The yield 
of the desired product was 84%.


Example 145
        
The reaction of Example 133 was repeated, except that 3-(3,4-methylene-
dioxyphenyl)propylene was used in lieu of 3-phenylpropylene.
        
As a result, the conversion of the starting 3-(3,4-methylenedioxy-
phenyl)propylene was 95%, the yield of the intermediate 1-(3,4-methylene-
dioxyphenyl)-2,2-dimethoxypropane was 88%, the Pd turn-over number was 176,
and the yield of the desired 3,4-methylenedioxyphenylacetone was 87%.

        
Examples 153 to 155
        
The reaction of Example 133 was repeated, except that 0.10 mole of each 
of various 3-phenylpropylenes listed in Table 22 and 0.00025 mole of 
each of various amines listed in Table 22 were used in lieu of those of 
Example 133 and that 0.0005 mole of palladium bromide was used in lieu 
of palladium chloride.
        
The results are shown in Table 22.
        
                                  TABLE 22


N.  3-phenylpropylenes    phenylacetones  Conv. Yield  Pd turn. Amine

154  3-(3,4-MDP)propylene MDP2P  99%      94%   92 %   188      N-Me Piperidine


Example 134
        
A 0.10 mole amount of the starting 3-(3,4-dimethoxyphenyl) propylene, 
0.25 mole of methyl nitrite, 0.5 liter of methyl alcohol, 0.00025 mole 
of triethylamine, and 0.0005 mole of a palladium chloride catalyst were 
charged into a reaction vessel. The reaction was carried out at a 
temperature of 20.degree. C. for 1.5 hours.
        
Then, the reaction mixture was hydrolyzed at 50.degree. C. for 60 
minutes by adding 36 g of water thereto.
        
The results are shown in Table 20.

        
Examples 146 to 152
        
The reaction of Example 134 was repeated, except that each of various 
3-phenylpropylenes listed in Table 21 was used in lieu of 
3-(3,4-dimethoxyphenyl)propylene.
        
The results are shown in Table 21.
        
                                  TABLE 21

N.  3-phenylpropylenes    phenylacetones  Conv.   Yield     Pd turn-over
 
149  3-(3,4-MDP)propylene MDP2P        96%        90%      180


Example 156 to 158
        
A 0.10 mole amount of each of the starting 3-phenylpropylene listed in 
Table 23, 0.25 mole of n-butyl nitrite, 0.5 liter of n-butyl alcohol, 
0.00025 mole of triethylamine, and 0.0005 mole of a palladium chloride 
catalyst were charged into a reaction vessel. The reaction was carried 
out at a temperature of 60.degree. C. for 1.5 hours. Then, the reaction 
mixture was hydrolyzed at a temperature of 50.degree. C. for 60 minutes 
by adding 36 g of water thereto.
        
The results are shown in Table 23.
        
                                  TABLE 23

N.  3-phenylpropylenes  phenylacetones   Conversion   Dialkoxy   Ketone   
Pd turn-over
 
156  3-(3,4-methylene-dioxyphenyl) propylene   62%       56%        54 %        
112
       3,4-methylene-dioxyphenyl acetone

Example 159
        
A 0.10 mole amount of the starting 3-(3,4-dimethoxyphenyl)propylene, 
0.25 mole of methyl nitrite, 0.5 liter of methyl alcohol, and 0.003 mole 
(corresponding to 0.006 mole of palladium atom) of the dimer of 
dichloroethylene palladium (II) as a catalyst were charged into a 
reaction vessel. Then, the reaction was carried out at a temperature of 
20.degree. C. for 1.5 hours.
        
After the completion of the reaction, the reaction mixture was gas 
chromatographically analyzed to quantitatively determine the unreacted 
starting material and the resultant intermediate 
1-(3,4-dimethoxyphenyl)-2,2-dimethoxypropane. As a result, the 
conversion of the starting material was 100% and the yield of the 
intermediate product was 92%.
        
The reaction mixture (containing the intermediate product) obtained 
above was hydrolyzed at a temperature of 50.degree. C. for 60 minutes by 
adding 36 g of water thereto.
        
After the completion of the hydrolysis, the desired 
3,4-dimethoxyphenylacetone was quantitatively determined by a gas 
chromatographical analysis. The yield of the desired product was 91%.
 
Example 162
        
The reaction of Example 159 was repeated, except that 0.10 mole of 
3-(3,4-methylenedioxyphenyl)propylene as a starting material and 0.006 
mole of bis(benzonitrile) palladium (II) chloride were used.
        
As a result, the conversion of the starting material was 100%, the yield 
of the intermediate 1-(3,4-methylenedioxyphenyl)-2,2-dimethoxypropane 
was 90%, and the yield of the desired 3,4-methylenedioxyphenylacetone 
was 89%.
       
Example 164
        
A 0.10 mole amount of the starting 3-phenylpropylene, 0.25 mole of 
methyl nitrite, 0.5 liter of methyl alcohol, 0.0005 mole of palladium 
chloride, and 0.0025 mole of cuprous chloride, were charged into a 
reaction vessel. Then, the reaction was carried out at a temperature of 
20.degree. C. for 1.5 hours.
        
After the completion of the reaction, the reaction mixture was gas 
chromatographically analyzed to quantitatively determine the unreacted 
starting material and the resultant intermediate 
1-phenyl-2,2-dimethoxypropane. As a result, the conversion of the 
starting material was 96%, the yield of the intermediate product was 
86%, and the Pd turn-over number was 172.
        
The reaction mixture (containing the intermediate product) obtained 
above was hydrolyzed at a temperature of 50.degree. C. for 60 minutes by 
adding 36 g of water thereto.
        
After the completion of the hydrolysis, the desired phenylacetone was 
quantitatively determined by a gas chromatographical analysis. The yield 
of the desired product was 85%.
        
Examples 165 to 170
        
The reaction of Example 164 was repeated, except that 0.10 mole of each 
of 3-phenylpropylenes listed in Table 24 was used as a starting material 
and that 0.0025 mole of CuCl.sub.2 or CuCl was used as a copper 
compound.
        
The results are shown in Table 24.
        
                                  TABLE 24

N.  3-phenylpropylenes  phenylacetones   Conversion   Dialkoxy   Ketone   
Pd turn-over
      Copper salt
 
169  3-(3,4-methylene-dioxyphenyl) propylene   96%       90%        90 %        
180
       3,4-methylene-dioxyphenyl acetone
      CuClsub2

Example 171 to 173
        
A 0.10 mole amount of the starting 3-phenylpropylene, listed in Table 
25, 0.25 mole of n-butyl nitrite, 0.5 liter of n-butyl alcohol, 0.0025 
mole of CuCl.sub.2 as a copper compound, and 0.0005 mole of a palladium 
chloride catalyst were charged into a reaction vessel. The reaction was 
carried out at a temperature of 60.degree. C. for 1.5 hours.
        
After completion of the reaction, the reaction mixture was treated in 
the same manner as in Example 159.
        
The results are shown in Table 25.
        
                                  TABLE 25

No.  3-phenylpropylenes   phenylacetones  Conversion   Dialkoxy   Ketone  Pd turn-over
 
173  3-(3,4-MDP)propylene MDP2P           67%          60%        61 %    120  


