JPH08245508A - Unsaturated carboxylic acid ester and its production - Google Patents

Abstract

PURPOSE: To obtain the subject compound, having a low content of geometrical isomers and useful as a perfume, a flavor ingredient, an intermediate, etc., for medicines and agrochemicals by reacting an unsaturated sulfonic acid ester with a malonic diester in the presence of a base, heating the resultant product in the coexistence of water and carrying out the decarboxylating reaction. CONSTITUTION: An unsaturated sulfonic acid ester having a C-C unsaturated bond is reacted with a malonic diester of formula I (R<8> is H or a 1-20C hydrocarbon; R<9> and R<10> are each a 1-20C hydrocarbon) in the presence of a base to afford a 2-substituted malonic diester compound, which is then heated in the coexistence of water (preferably in a molar amount of 1-3 times) at 40-250 deg.C, preferably 120-180 deg.C to carry out the decarboxylating reaction. Thereby, the objective compound of formula II [R<1> and R<4> are each a 1-20C hydrocarbon; R<2> and R<3> are each H or a 1-20C hydrocarbon; n is >=20] having <=1.0wt.% content of geometrical isomer is obtained.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to an unsaturated carboxylic acid ester useful as a flavor and a flavor component, and more specifically to an unsaturated carboxylic acid ester having a very small content of geometrical isomers which gives a different odor, and a method for producing the same. Regarding

[0002]

BACKGROUND OF THE INVENTION Unsaturated carboxylic acid esters such as ethyl (Z) -4-decenoate, ethyl (Z) -5-octenoate and ethyl (Z) -3-hexenoate are used as grape, karin and tea, respectively. Although it is used as a flavor component, etc., the isomer (E) form has a different scent, and since it can hardly be separated even by distillation, the establishment of a manufacturing method with a low (E) form content has been established. Is desired.

Conventionally, as a method for producing these (Z) type unsaturated carboxylic acid esters, for example, Indian J.
Chem. , 19B , 950 (1980), cis-hydrogenated 2-octyne-1-ol with a Lindlar catalyst was reacted with (Z) -2-octen-1-ol to react with phosphorus tribromide (Z). ) -2-octene-1-bromide was synthesized, and using this (Z) type bromide compound,
It discloses a method for producing ethyl (Z) -4-decenoate by reacting with diethyl malonate anion and then heating in the presence of water for decarboxylation reaction. However, in this method, the yield is not sufficient, and since the double bond is isomerized due to the use of the halide, a large amount of the (E) isomer having a different odor is produced as a by-product, so that the purity of the (Z) isomer is high. However, there is a problem that ethyl 4-decenoate, which is highly expensive, cannot be obtained.

Further, German Patent Publication No. 263868 discloses 1-bromo- in the presence of a catalyst composed of metallic lithium and di (trimethylphosphite) iodocuprate.
Although a method of synthesizing ethyl (Z) -4-decenoate by reacting (Z) -1-heptene with ethyl acrylate is disclosed, in this method, a halide compound is used in the same manner as in the above reaction. There are many by-products of the (E) form, and it is necessary to go through a multistep process to synthesize the starting material α-halo-α-olefin, and the (Z) form high-purity starting material (α-
It has drawbacks such as difficulty in obtaining halogenated-α-olefin).

Further, Synthesis, 10 , 82
6 (1979) is obtained by reacting lithium (diethyl) cuprate with acetylene, and reacting ((Z) -1-butenyl) cuprate with ethyl 4-halobutyrate to give (Z) -5-octene. Although a method of synthesizing ethyl acid has been reported, in this method, it is difficult to say that the selectivity of geometric isomerism is sufficient because the double bond is formed by the reaction with acetylene, and the catalyst is expensive and can be adjusted. There are problems such as severe conditions such as dryness.

[0006]

DISCLOSURE OF THE INVENTION The inventors of the present invention have made extensive studies in view of the above circumstances, and as a result, the (E) content is 1%.
Reaction with diethyl malonate under basic conditions using (Z) type unsaturated sulfonic acid ester which can be easily obtained from less than the weight of (Z) type unsaturated alcohol and mesyl chloride without isomerization of unsaturated bond To produce a 2-substituted diethyl malonate, and then the 2-substituted diethyl malonate is heated in the presence of water to carry out a decarboxylation reaction. It was found that an extremely small amount of (Z) type unsaturated carboxylic acid ester was obtained in good yield, and the present invention was completed.

[0007]

Thus, according to the present invention, the general formula (1)

Embedded image (In the formula, R ¹ and R ⁴ each independently have 1 carbon atom.
To 20 hydrocarbon groups, R ² and R ³ are each independently a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms,
n represents an integer of 20 or less. ), And the unsaturated carboxylic acid ester having a geometric isomer content of 1.0% or less, and an unsaturated sulfonic acid ester having a carbon-carbon unsaturated bond, and a malonic acid diester are reacted in the presence of a base. There is provided a method for producing an unsaturated carboxylic acid ester, which comprises heating the resulting 2-substituted malonic acid diester compound in the presence of water to carry out a decarboxylation reaction.

The unsaturated carboxylic acid ester of the present invention has the general formula (1)

Embedded image It is represented by. R ¹ and R ⁴ in the formula each independently represent a hydrocarbon group having 1 to 20 carbon atoms, preferably 1 to 10 carbon atoms, and more preferably 1 to 6 carbon atoms. Examples of the hydrocarbon group include an alkyl group, an alkenyl group, an alkynyl group,
Examples thereof include a cycloalkyl group, an aryl group and an aralkyl group, and an alkyl group is preferable. The double bond in the case of an alkenyl group may be either (Z) or (E). R ² and R ³ each independently represent a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms, preferably 1 to 10 carbon atoms, more preferably 1 to 6 carbon atoms similar to R ¹ .
It is preferably a hydrogen atom or a lower alkyl group, more preferably a hydrogen atom. n represents an integer of 20 or less,
It is preferably an integer of 1 to 10, more preferably an integer of 1 to 6.

Specific examples of the hydrocarbon group include, for example, methyl group, ethyl group, n-propyl group, iso-propyl group, n-butyl group, iso-butyl group, sec-butyl group, t-butyl group, n. -Pentyl group, iso-pentyl group, neo-pentyl group, 1-methylpentyl group, 2-
Methylpentyl group, 3-methylpentyl group, n-hexyl group, iso-hexyl group, n-heptyl group, iso-
Heptyl group, n-octyl group, iso-octyl group, 2
-Ethylhexyl group, nonyl group, decyl group, undecyl group, dodecyl group, tetradecyl group, pentadecyl group, hexadecyl group, octadecyl group, eicosyl group, and other alkyl groups; allyl group, (Z) -2-butenyl group, (E)
-2-butenyl group, 3-butenyl group, iso-butenyl group, 4-pentenyl group, (Z) -3-pentenyl group,
(Z) -2-pentenyl group, (E) -2-pentenyl group, 1-pentenyl group, 3-methyl- (Z) -2-pentenyl group, 5-hexenyl group, (Z) -3-hexenyl group, (Z) -2-Hexenyl group, alkenyl group such as heptenyl group; 2-butynyl group, 3-butynyl group, 4-pentynyl group, 3-pentynyl group, 2-pentynyl group, 5
-Hexynyl group, 3-hexynyl group, heptynyl group, octynyl group, decynyl group, dodecynyl group, octadecynyl group, alkynyl group such as eicosinyl group; cyclopentyl group, cyclohexyl group, cycloheptyl group, cyclooctyl group, cyclododecyl group, etc. Examples thereof include a cycloalkyl group; an aryl group such as a phenyl group, a 2-methylphenyl group, a 4-methylphenyl group, and a naphthyl group; and an aralkyl group such as a benzyl group.

The geometric isomer content of the unsaturated carboxylic acid ester of the present invention is 1.0% by weight or less, preferably 0.5% by weight or less, more preferably 0% by weight based on the total amount of the unsaturated carboxylic acid ester of interest. It is 0.25% by weight or less.

Further, in the present invention, a 2-substituted malonic acid dialkyl ester obtained by reacting an unsaturated sulfonic acid ester having a carbon-carbon unsaturated bond with a malonic acid dialkyl ester under basic conditions is present in the presence of water. By carrying out the decarboxylation reaction by heating to 0 ° C., a method for producing an unsaturated carboxylic acid ester in which the isomerization reaction of a carbon-carbon unsaturated bond is extremely small is provided. In this reaction, a geometric isomer content of 1% by weight or less, preferably 0.5% by weight or less, and more preferably 0.25% by weight or less is used as a raw material, whereby an extremely high geometric isomer content is obtained. The unsaturated carboxylic acid ester having a low content can be produced.

First stage: unsaturated sulfone as a raw material
Preparation of Acid Ester As the unsaturated sulfonic acid ester used in the present invention, those produced by a conventional method can be used,
For example, it can be obtained by reacting an unsaturated alcohol with a sulfonic acid halide in the presence of an alkali.

Examples of the unsaturated alcohol used include those represented by the general formula (2)

[Chemical 4] (In the formula, R ⁵ is the same as R ¹ , R ⁶ and R ⁷ are independently the same as R ^2, and m is the same as n.)
As the unsaturated alcohol having a low geometric isomer content, for example, a (Z) type unsaturated alcohol obtained by hydrogenating the corresponding alkynyl alcohol with a Lindlar catalyst or the like can be used.

The sulfonic acid halide used is
For example, general formula (3)

Embedded image (In the formula, R ¹¹ represents an alkyl group, an aryl group or an aralkyl group, and X represents a chlorine atom or a bromine atom.). The carbon number of R ¹¹ is not particularly limited, but is usually 20 or less, preferably 1 to 15, and more preferably 1 to 10.
It is a range of pieces. Specific examples of R ¹¹ include, for example, methyl group, ethyl group, n-propyl group, iso-propyl group,
n-butyl group, iso-butyl group, sec-butyl group,
Examples thereof include t-butyl group, phenyl group, o-toluyl group, p-toluyl group, mesityl group, 1-naphthyl group and 2-naphthyl group.

Representative compounds of such sulfonic acid halides include, for example, methanesulfonic acid chloride, benzenesulfonic acid chloride, p-toluenesulfonic acid chloride, o-toluenesulfonic acid chloride, naphthalenesulfonic acid chloride, mesitylenesulfonic acid chloride and the like. Sulfonic acid chloride compounds; sulfonic acid bromide compounds such as methanesulfonic acid bromide and p-toluenesulfonic acid bromide, and the like, and particularly sulfonic acid chloride compounds such as methanesulfonic acid chloride and p-toluenesulfonic acid chloride are widely used. .

The amount of the sulfonic acid halide used is usually equimolar or more, preferably 1 to 5 times, and more preferably 1 to 2 times the molar amount of the alcohol used.

As the alkali to be used, one which is usually used in the reaction of alcohol and sulfonic acid halide may be used, and for example, sodium carbonate, potassium carbonate, lithium carbonate, magnesium carbonate, calcium carbonate, barium carbonate, hydrogen carbonate. Carbonates such as sodium and potassium hydrogen carbonate; inorganic bases such as sodium hydroxide, potassium hydroxide, calcium hydroxide, barium hydroxide, magnesium hydroxide and other hydroxide compounds; trimethylamine, triethylamine, N-methylmorpholine, N
-Tertiary aliphatic amines such as ethylmorpholine and diisopropylethylamine; N, N-dimethylaniline,
Examples include tertiary aromatic amines such as N, N-diethylaniline; organic bases such as pyridines such as 2,6-lutidine and pyridine; preferably inorganic bases, more preferably alkali metals or alkaline earths. Examples include metal carbonates and hydroxides.

The amount of the alkali used is not particularly limited depending on the reaction conditions, but is 1 mol or more, preferably 1 to 10 times, and more preferably 1 to 5 times the mol amount with respect to 1 mol of the usually used alcohols. Used. If the amount of alkali used is too small, the reaction does not proceed sufficiently, and if it is too large, side reactions occur.

In the sulfonic acid esterification reaction from unsaturated alcohol, a solvent may be used if necessary. The solvent to be used is not particularly limited as long as it does not inhibit this reaction, but it is usually hydrocarbons such as n-hexane, toluene and benzene; halogenated hydrocarbons such as methylene chloride, chloroform and ethylene chloride. Nitrile hydrocarbons such as acetonitrile, propionitrile and benzonitrile; ethers such as dimethyl ether, diethyl ether, dioxane, tetrahydrofuran, ethylene glycol dimethyl ether;
Esters such as ethyl acetate and ethyl butyrate; acetone,
Organic solvents such as ketones such as methyl isobutyl ketone are used, and hydrocarbons and halogenated hydrocarbons are preferable. The amount of the organic solvent used is not particularly limited, but is usually 0 with respect to 1 mol of the unsaturated alcohol used.
It is in the range of ˜1000 ml, preferably 0 to 800 ml, and more preferably 0 to 500 ml. It is also possible to use water as an organic-water biphasic solvent.

The reaction conditions for the sulfonic acid esterification are not particularly limited, and are appropriately selected depending on the kind of raw materials used. Usually, the reaction temperature is not higher than the boiling point of the solvent, preferably −
It is in the range of 30 ° C to 50 ° C, more preferably -15 to 10 ° C, the reaction pressure is 10 kg / cm or less, usually atmospheric pressure, and the reaction time is within 10 hours, preferably within 5 hours,
More preferably, it is in the range of 10 minutes to 3 hours. Although the reaction conditions are not limited to these, it should be noted that if the reaction time is excessively long, the isomerization reaction is increased and other by-products are also formed, which makes the subsequent purification step difficult. .

After completion of the reaction, the corresponding unsaturated sulfonic acid ester can be obtained by carrying out operations such as liquid separation, extraction, washing, drying, and concentration according to a conventional method. The sulfonic acid ester thus obtained has the general formula (4)

[Chemical 6] (In the formula, R ⁵ , R ⁶ , R ⁷ and R ¹¹ are the same as described above.).

Second stage: unsaturated sulfonate ester and
Reaction of Rhonic Acid Diester Malonic acid diester easily forms a 2-substituted malonic acid diester when an anion is formed at the 2-position under basic conditions and reacts with a sulfonic acid ester. It can be obtained by adding malonic acid diester.

Examples of the malonic acid diester used in the present invention include those represented by the general formula (5)

[Chemical 7] (In the formula, R ⁸ is the same as R ² above, and R ⁹ and R ¹⁰ are independently the same as R ⁴ above.). The amount of malonic acid diester used is usually 1 equivalent or more, preferably 1 to 5 with respect to the unsaturated sulfonic acid ester used.
The range is equivalent, more preferably 1 to 2 equivalents.

Examples of the base used in the present invention include alkali metal hydroxides such as sodium hydroxide and potassium hydroxide; alkaline earth metal hydroxides such as calcium hydroxide and magnesium hydroxide; sodium carbonate and potassium carbonate. Alkali metal carbonates such as; Alkaline earth metal carbonates such as magnesium carbonate and calcium carbonate; Alkali metal alcosides such as sodium methylate and sodium ethylate; Alkaline earth metal alcosides such as magnesium ethylate; Lithium hydride, hydrogen Alkali metal hydrides such as sodium hydride; Alkaline earth metal hydrides such as magnesium hydride and calcium hydride; Alkali metal amides such as lithium amide, lithium diisopropylamide and sodium amide; And the like, preferably an alkali metal carbonate, an alkali metal alkoxide, an alkali metal hydride, an alkali metal amide, an organic alkali metal compound such as alkyllithium, more preferably an alkali metal alkoxide, an alkali metal hydride and the like. is there. The amount of the base used is usually 1 equivalent or more, preferably 1 to 3 equivalents, and more preferably 1 to 1.5 equivalents based on the malonic acid diester.

In the reaction of the sulfonic acid ester and the malonic acid diester, a solvent may be used if necessary.
The solvent used is not particularly limited as long as it does not inhibit this reaction, but is usually methanol, ethanol, n-propyl alcohol, iso-propyl alcohol, n-butyl alcohol, iso-butyl alcohol, t-butyl. Alcohols such as alcohols; hydrocarbons such as n-hexane, toluene, benzene; ethers such as dimethyl ether, diethyl ether, diiso-propyl ether, tetrahydrofuran, dioxane; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, etc. Are exemplified, and alcohols, hydrocarbons, ketones and the like are preferable. The amount of the solvent used is not particularly limited, but usually 0 to 1000 ml per mol of the malonic acid diester used,
The range is preferably 100 to 800 ml, more preferably 200 to 600 ml.

The reaction conditions are not particularly limited and may be appropriately selected depending on the type of raw materials used. Usually, the reaction temperature is not higher than the boiling point of the solvent, preferably -30 ° C to 100.
° C., in the range of more preferably 0 to 80 ° C., the reaction pressure is 10 kg / cm ² or less, usually atmospheric pressure, the reaction time is within 10 hours, preferably within 5 hours, more preferably 1 to 3 hours It is a range. The reaction conditions are not limited to these, but if the reaction temperature is excessively high or the reaction time is excessively long, the isomerization reaction is increased and the subsequent purification step becomes difficult. is there.

After completion of the reaction, operations such as liquid separation, extraction, washing, drying, and concentration are performed according to a conventional method to give the corresponding general formula (6).

Embedded image (In the formula, R ⁵ , R ⁶ , R ⁷ , R ⁸ , R ⁹ and R ¹⁰ are the same as described above.) A 2-substituted malonic acid diester represented by the formula is obtained.

Third stage; of 2-substituted malonic acid diesters
Decarboxylation reaction By heating the obtained 2-substituted malonic acid diester in the presence of water to carry out a decarboxylation reaction, one alkyl ester group is replaced with a hydrogen atom, and the target unsaturated carboxylic acid ester is obtained. Obtainable.

The water used in the present invention can be used alone or as a mixture with an organic solvent. The amount of water used is 1 mol of 2-substituted malonic acid ester,
It is usually in the range of 1 to 10 mol, preferably 1 to 6 mol, more preferably 1 to 3 mol. The organic solvent that can be used in combination with water is, for example, the same as the solvent that can be used in the reaction of unsaturated sulfonic acid and malonic acid diester, and the amount thereof is usually 0 with respect to 1 mol of 2-substituted malonic acid ester.
It is in the range of ~ 200 ml, preferably 0-100 ml, more preferably 0-50 ml.

The heating temperature for the decarboxylation reaction is usually 40 to 25.
0 ° C, preferably 80 to 200 ° C, more preferably 1
It is in the range of 20 to 180 ° C.

In order to suppress isomerization during the decarboxylation reaction, it is necessary to sufficiently remove the acid component in the starting 2-substituted malonic acid diester or to allow an acid remover to coexist in the reaction system. Particularly preferred. Examples of the acid removal in the 2-substituted malonic acid diester include a method of sufficiently washing with an alkaline aqueous solution such as an aqueous sodium hydroxide solution and an aqueous sodium hydrogen carbonate solution. Examples of the acid remover coexisting in the reaction system include alkali metal hydroxides such as sodium hydroxide and potassium hydroxide; alkaline earth metal hydroxides such as calcium hydroxide and magnesium hydroxide; sodium carbonate and potassium carbonate. Alkali metal carbonates such as; and alkaline earth metal carbonates such as magnesium carbonate and calcium carbonate. The amount of the acid remover used is usually in the range of 0.1 to 50 g, more preferably 1 to 20 g, based on 1 mol of the 2-substituted malonic acid ester.

After completion of the reaction, the desired unsaturated carboxylic acid ester is obtained by separation, extraction, washing, drying, concentration and, if necessary, purification operations such as chromatography and distillation according to a conventional method. You can For example,
From the 2-substituted malonic acid diester of the general formula (6), the general formula (7)

[Chemical 9] (In the formula, R ⁵ , R ⁶ , R ⁷ , R ⁸ and R ⁹ are the same as the above.), And the unsaturated carboxylic acid is obtained.

The embodiments of the present invention will be described below. (1) General formula (1)

[Chemical 10] (In the formula, R ¹ and R ⁴ each independently have 1 carbon atom.
To 20 hydrocarbon groups, R ² and R ³ are each independently a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms,
n represents an integer of 20 or less. ) And having a geometrical isomer content of 1.0% by weight or less. (2) The unsaturated carboxylic acid ester having a geometric isomer content of 0.5% by weight or less, more preferably 0.25% by weight or less. (3) The preferred carbon number of R ¹ , R ² , R ³ and R ⁴ is 1 to
The unsaturated carboxylic acid ester is 10 or more preferably 1 to 6. (4) The hydrocarbon groups of R ¹ , R ² , R ³ and R ⁴ are each independently an alkyl group, an alkenyl group, an alkynyl group, a cycloalkyl group, an aryl group or an aralkyl group, preferably an alkyl group. And the unsaturated carboxylic acid ester. (5) The unsaturated carboxylic acid ester wherein R ² and R ³ are hydrogen atoms or lower alkyl groups. (6) The unsaturated carboxylic acid ester wherein n is preferably an integer of 1 to 10, more preferably an integer of 1 to 6. (7) The method for producing the unsaturated carboxylic acid ester, wherein the unsaturated carboxylic acid ester is a (Z) type unsaturated carboxylic acid ester, and the geometric isomer is a (E) isomer.

(8) A 2-substituted malonic acid diester compound obtained by reacting an unsaturated sulfonic acid ester having a carbon-carbon unsaturated bond with a malonic acid dialkyl ester anion under basic conditions is heated in the presence of water. A method for producing an unsaturated carboxylic acid ester, which comprises carrying out a decarboxylation reaction by means of (9) The said manufacturing method whose carbon-carbon unsaturated bond is a double bond. (10) The production method as described above, wherein the unsaturated sulfonic acid ester is obtained by reacting an unsaturated alcohol and a sulfonic acid halide in the presence of an alkali. (11) The unsaturated sulfonic acid ester is represented by the general formula (4)

[Chemical 11] (In the formula, R ⁵ , R ⁶ , R ⁷ , R ¹¹ and m are the same as the above.), And the malonic ester is represented by the general formula (5).

[Chemical 12] (Wherein R ⁸ , R ⁹ , R ¹⁰ and m are the same as described above), and the 2-substituted malonic acid diester is represented by the general formula (6).

[Chemical 13] (Wherein R ⁵ R, R ⁶ , R ⁷ , R ⁸ , R ⁹ , R ¹⁰ and m are the same as above), and the resulting unsaturated carboxylic acid ester is represented by the general formula (7)

Embedded image (In the formula, R ⁵ , R ⁶ , R ⁷ , R ⁸ , R ⁹ and m are the same as the above). (12) The unsaturated sulfonic acid ester represented by the general formula (4) has the general formula (2)

[Chemical 15] (In the formula, R ⁵ , R ⁶ , R ⁷ and m are the same as above.) And the unsaturated alcohol represented by the general formula (3).

Embedded image (In the formula, R ¹¹ and X have the same meanings as described above.) The above-mentioned production method, wherein a sulfonic acid haloid represented by the formula is reacted. (13) The production method as described above, wherein the sulfonic acid halide is at least one selected from sulfonic acid chloride and sulfonic acid bromide. (14) The amount of sulfonic acid halide used is alcohol 1
The above production method is equimolar or more, preferably 1 to 5 mol, and more preferably 1 to 2 mol with respect to mol. (15) The production method described above, wherein the alkali is at least one selected from organic bases and inorganic bases. (16) The production method as described above, wherein the amount of alkali used is 1 mol or more, preferably 1 to 10 mol, and more preferably 1 to 5 mol, per 1 mol of alcohol. (17) The production method as described above, wherein the amount of malonic acid diester used is 1 equivalent or more, preferably 1 to 5 equivalents, and more preferably 1 to 2 equivalents, relative to the sulfonic acid ester. (18) The base is an alkali metal hydroxide, an alkaline earth metal hydroxide, an alkali metal carbonate, an alkaline earth metal carbonate, an alkali metal alcoside, an alkaline earth metal alcoside, an alkali metal hydride, an alkaline earth metal The above-mentioned production method, which is at least one selected from hydrides, alkali metal amides and organic alkali metal compounds. (19) The production method as described above, wherein the amount of the base used is at least 1 equivalent, preferably 1 to 3 equivalents, and more preferably 1 to 1.5 equivalents, relative to the malonic acid diester. (20) The amount of water used is 2-substituted malonic acid diester 1
The said manufacturing method which is 1-10 mol with respect to a mol, Preferably it is 1-6 mol, More preferably, it is 1-3 mol. (21) The heating temperature for the decarboxylation reaction is 40 to 250 ° C, preferably 80 to 200 ° C, more preferably 120 to 1
The said manufacturing method which is 80 degreeC. (22) The production method as described above, wherein an acid remover is added during the decarboxylation reaction. (23) The production method as described above, wherein the acid remover is at least one selected from alkali metal hydroxides, alkaline earth metal hydroxides, alkali metal carbonates and alkaline earth metal carbonates. (24) The amount of the acid remover used is 0.1 to 50 g, preferably 1 to 20 per 1 mol of the 2-substituted malonic acid ester.
The manufacturing method which is g.

(25) The content of the geometric isomer of the unsaturated sulfonic acid ester is 1.0% by weight or less, preferably 0.5
The above-mentioned production method, wherein the unsaturated carboxylic acid ester is the unsaturated carboxylic acid ester according to any one of (1) to (9), wherein the unsaturated carboxylic acid ester is not more than 0.25% by weight, more preferably not more than 0.25% by weight.

[0036]

EXAMPLES The present invention will be described in detail below with reference to examples, but the present invention is not limited to the following examples.

Example (First Step) 400 g of (Z) -3-hexen-1-ol was added to a 2 liter reactor equipped with a mechanical stirrer.
(4.0 mol, E-form content 0.10%) and 378 g (4.8 mol) of pyridine were charged and cooled to 0 ° C.
Then, to this was added methanesulfonyl chloride 504.2.
g (4.4 mol) was added dropwise with stirring for 4 hours and 30 minutes so that the internal temperature did not exceed 5 ° C., and stirring was continued for 5 hours to complete the reaction. Next, 1.2m hydrochloric acid aqueous solution 700m
l was added to dissolve the precipitate, and the mixture was extracted 4 times with 200 ml of ethyl acetate. The extract was washed 3 times with 300 ml of saturated aqueous sodium hydrogen carbonate solution and then with 400 ml of water.
The extract was washed 3 times with 300 ml of saturated saline and dried overnight with magnesium sulfate, and then ethyl acetate was distilled off to give 711 g of (Z) -3-hexenyl methanesulfonate (GC measurement; yield 97.0%, purity). 97.2%, E-form content 0.15
%) Was obtained. In addition, the identification of the (Z) body and the (E) body is performed by GC-
The analysis was performed by MS analysis, and the content of (E) form was determined by comparing the peak areas of GC analysis. Below, the measurement conditions of GC are shown below. Device: Shimadzu Corporation GC-14A column: GL Sciences NEUTRABON
D-1 (50 m × 0.25 mmφ) column temperature: 80 ° C. → 280 ° C. (10 ° C./min)

(Second step) Dry ethanol 1 was added to a 3 liter reactor equipped with a mechanical stirrer and a reflux condenser.
650 ml was charged, and 74.4 g (3.3 mol) of metallic sodium having a size of 1 cm square or less was gradually added thereto, and the mixture was stirred until completely dissolved. Next, this ethanol solution was heated to 50 ° C., and 557.7 g of diethyl malonate was added.
(3.4 mol) was added dropwise over 1 hour, and then (Z) -3-hexenyl methanesulfonate synthesized in the first step 540
g (3.0 mol) was gradually added dropwise over 3 hours. After the dropping, the reaction liquid was heated to 80 ° C. and reacted under reflux for 4 hours. After the reaction was completed, the reaction solution was cooled to room temperature and water 850
After adding ml, the precipitate was dissolved and then separated into an organic layer and an aqueous layer.
The aqueous layer was extracted 4 times with 500 ml of ethyl acetate and combined with the organic layer. The organic layer is 200m of 1.2M hydrochloric acid aqueous solution.
After washing with 1, further saturated aqueous sodium hydrogencarbonate solution 20
0 ml twice, 200 ml water 4 times, saturated saline solution 200
After being washed with ml three times and dried over magnesium sulfate overnight, ethyl acetate was distilled off to give 734 g of diethyl 2-((Z) -3-hexenyl) malonate (yield 77.6%, purity 76.
6%, E-form content 0.15%) was obtained. As a by-product, diethyl 2,2-di ((Z) -3-hexenyl) malonate was produced at 8.8%.

(Third step) In a 1 liter reactor equipped with a magnetic stirrer and a Witmer type fractionating tube, 569 g (1.8 moles) of diethyl 2-((Z) -3-hexenyl) malonate synthesized in the second step. Purity of 76.6%) and 12 g of potassium carbonate (0.091 mol) were charged, and the internal temperature was raised to 190 ° C while stirring. Water was injected into the heated reaction solution through an injection needle at a rate of double equivalent in 5 hours,
A decarboxylation reaction was performed. The end of the decarboxylation reaction is G of the reaction solution.
It was determined by confirming that the starting material, diethyl 2-((Z) -3-hexenyl) malonate, disappeared by C. After the completion of the decarboxylation reaction, the solid matter was filtered off from the reaction solution, and then water 10
Wash with 0 ml to give crude ethyl (Z) -5-octenoate 32
7 g (purity 93.2%, yield 99.1%) was obtained. The crude ethyl (Z) -5-octenoate was distilled to collect a fraction having a vacuum degree of 20 Torr and a top temperature of 100 ° C. and a purity of 9%.
296 g of ethyl (Z) -5-octenoate (9.8%, distillation yield 90%, E-form content 0.19%) was obtained.

Comparative Example (First Step) In a 200 ml reactor equipped with a mechanical stirrer, the same (Z) -3-hexen-1-ol 40 g (0.4 mol) as in Example and 200 ml of diethyl ether were used.
And 1.58 g (0.02 mol) of pyridine,
Cooled to 0 ° C. Then, to this, 54.1 g of phosphorus tribromide
(0.2 mol) was added dropwise over 20 minutes so that the internal temperature did not exceed 5 ° C, then at 0 ° C for 1 hour and then at 25 ° C for 5 minutes.
The stirring was continued for an hour to complete the reaction. Next, 50 ml of ice water
Was added to dissolve the precipitate, and the mixture was separated, and the organic layer was washed once with 20 ml of 1.2M aqueous hydrochloric acid solution, then with 10 ml of water three times, separated, dried over calcium carbonate overnight, and then dried with diethyl ether. Was distilled off, and 63.8 g of 1-bromo- (Z) -3-hexene (GC measurement; yield 96.0%, purity 98.2).
%, E-form content 0.48%) was obtained.

(Second step) Dry ethanol 2 was added to a 500 ml reactor equipped with a mechanical stirrer and a reflux condenser.
50 ml was charged, 4.7 g (0.2 mol) of sodium metal having a size of 1 cm square or less was gradually added, and the mixture was stirred until it was completely dissolved. Then, add this ethanol solution to 5
After heating to 0 ° C., diethyl malonate 34.3 g (0.21
Mol) in 13 minutes and then 1-bromo-
33.2 g (0.2 mol) of (Z) -3-hexene was added to 20
Gradually dropped in minutes. After the dropping, the reaction solution was heated to 80 ° C. and reacted under reflux for 2 hours. After the reaction was completed, 100 ml of water was added to the reaction solution to dissolve the precipitate, and ethyl acetate 30
Extraction was carried out 3 times with ml, followed by washing once with 100 ml of water and 3 times with 30 ml of saturated saline and drying overnight with magnesium sulfate, and then the solvent was distilled off to give 2-((Z) -3-hexenyl). There were obtained 48.2 g of diethyl malonate (yield 70.2%, purity 70.5%, E-form content 2.13%). It was confirmed that, as a by-product, diethyl 2,2-di (3-hexenyl) malonate was produced in an amount of 7.7% (Z-form and E-form about half each).

(Third step) 5 with magnetic stirrer
The 2-((Z)) synthesized in the second step was added to a 0 ml reactor.
Diethyl-3-hexenyl) malonate 17.2 g (0.
(05 mol) and 0.35 g (2.5 mmol) of potassium carbonate were charged, and the internal temperature was raised to 190 ° C while stirring. Water was injected into the heated reaction solution through an injection needle at a rate of twice equivalent for 5 hours to carry out decarboxylation reaction. After confirming the disappearance of the raw materials by GC, the solid matter is filtered off from the reaction solution, and water 100
Wash with ml to give crude ethyl (Z) -5-octenoate 8.7.
g (yield 83.5%, purity 81.6%, E-form content 2.31%) was obtained. Crude ethyl (Z) -5-octenoate was distilled, and a fraction having a vacuum degree of 20 Torr and a top temperature of 100 ° C. was collected to obtain ethyl (Z) -5-octenoate (distillation yield 8
8.4%, purity 98.8%, E-form content 2.72%)
I got

[0043]

The unsaturated carboxylic acid ester obtained by carrying out the present invention, especially the (Z) type unsaturated carboxylic acid ester, has a very low isomer content, and therefore,
It is used as a flavor component, an intermediate for medicines and agricultural chemicals, and is particularly useful as a flavor and a flavor component. In addition, the production method of the present invention hardly causes the isomerization reaction of the unsaturated bond, and since the desired unsaturated carboxylic acid ester can be obtained with good yield and purity, the sulfonic acid ester having an unsaturated bond is obtained. It can be used in many reactions to produce the corresponding unsaturated carboxylic acid esters from (or alcohols).

Claims (2)

[Claims] 1. A compound represented by the general formula (1): (In the formula, R ¹ and R ⁴ each independently have 1 carbon atom.
To 20 hydrocarbon groups, R ² and R ³ are each independently a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms,
n represents an integer of 20 or less. ) And having a geometrical isomer content of 1.0% by weight or less. 2. A 2-substituted malonic acid diester compound obtained by reacting an unsaturated sulfonic acid ester having a carbon-carbon unsaturated bond with a malonic acid diester in the presence of a base is heated in the presence of water to perform a decarboxylation reaction. A method for producing an unsaturated carboxylic acid ester, which comprises: