JPS6042776B2 - Method for producing 2,4,6,8-tetramethyldecanoic acid or its ester - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing 2,4,6,8-tetramethyldecanoic acid and its ester derivatives represented by the following formula (I).

\/ C02R (I) [In the formula (I), R represents a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms] ~shi 几大, mi (■) C02R look゛ (■) [Formula (■) The middle dotted line is the position indicated by this*2●
A compound with a 4,6,8-tetramethyldecanoic acid skeleton was found in waterfowl secretions [Nature) 1
9, 600 (1963)], and its structure was recently confirmed to be an ester of octadecyl alcohol [Biochemistry], No. 8, 17.
74 (1975)].

The octadecyl ester of the above acid is also called swan oil. In general, branched esters such as swan oil have a low freezing point and viscosity, and are highly chemically stable. Ideal for formulation in salt-containing products. Furthermore, such esters are characterized by high spreadability, and can be blended to make creams with good spreadability. The above formula (I)
It has been considered difficult to produce the complex compound expressed by total synthesis, and conventional studies have only focused on biochemical aspects.

Industrially, cetyl isooctanoate,
Isotridecyl isostearate, octyldodecyl isostearate, etc. are used, but it goes without saying that branched esters that are the same as natural products are desirable from the standpoint of safety for the human body. i Therefore, the purpose of the present invention is to produce 2,4,6,8-tetramethyldecanoic acid or its ester totally synthetically, which has the same structure as the natural product, and this purpose is achieved by the present invention. According to the following formula, 4,6,8-trimethyldecane-2-offune (■) is subjected to a cyanohydrination reaction, the product is dehydrated and solvolyzed in the presence of an acid, and the resulting This is achieved by hydrogenating a saturated carboxylic acid or its ester (■).

-H2O)ROH ゛CO2R (I) A step of hydrogenating 4,6,8-trimethyl-3-decen-2-one, which is represented by the presence of a double bond in either one of the two.

3. 2,4,6,8-tetramethyldecanoic acid or 2,4,6,8-tetramethyldecanoic acid according to claim 2, wherein 4,6-dimethyloctan-2-one of formula (■) is prepared by the following process. A method for producing the ester.

1. A step of reacting 11-halo-2-butene with mesityl oxide and/or isomethyl oxide, 2. The resulting 3-isopropenyl-5-heptene-2- represented by the following formula (■)
a step of rearranging 1, and a step of hydrogenating 4,6-dimethyl-3,7-octadien-2-one represented by the following formula (■) to be produced.

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing 2,4,6,8-tetramethyldecanoic acid and its ester derivatives represented by the following formula (1).

[In the formula (1), R represents a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms] 2●4●6●8-Tetramethyldecanoic acid skeleton compound was found in waterfowl secretions [Natur'Ell9λ600 (1963)],
Recently, its structure was confirmed to be an ester of octadecyl alcohol [BiOchemist
y. ．． Dan, NO. 8, 1774 (1975)].

The octadecyl ester of the above acid is also called swan oil. In general, branched esters such as swan oil have a low freezing point and viscosity, and are highly chemically stable, so they are not used in highly acidic or alkaline cosmetics such as rinse liquids, cold liquids, and oil shampoos, or higher fatty acid metal salts. It is ideal for formulating into products containing it. Furthermore, such esters are characterized by high spreadability, and can be blended to make creams with good spreadability. It has been considered difficult to produce the complex compound represented by the above formula (1) by total synthesis, and conventional studies have only been conducted mainly from a biochemical perspective.

Industrially, cetyl isooctanoate,
Isotridecyl isostearate, octyldodecyl isostearate, etc. are used, but it goes without saying that branched esters that are the same as natural products are desirable from the standpoint of safety for the human body. Therefore, the object of the present invention is to produce 2,4,6,8-tetramethyldecanoic acid or its ester totally synthetically, which has the same structure as the natural product; For example, as shown in the formula below, 4,6,8-trimethyldecane-2-offone (
This is achieved by subjecting (ii) to a cyanohydrination reaction, dehydrating and solvolyzing the product in the presence of an acid, and hydrogenating the resulting lower saturated carboxylic acid or its ester (■).

In the present invention, the cyanohydrination reaction of the Cl3 monosaturated ketone of formula (■) is carried out by the method generally employed in the synthesis of cyanohydrins by the addition reaction of cyanide to a carbonyl compound. You can do it by leaning.

Therefore, the reaction product has the following formula (
■'') cyanohydrin. Suitable cyanide compounds include hydrogen cyanide, cyanides of alkali metals such as sodium and potassium, cyanides of alkaline earth metals such as magnesium, calcium, strontium and barium, and ammonium cyanide. Particularly preferred are water-soluble cyanides.

Potassium cyanide or sodium cyanide are most preferably used in terms of availability or handling. These metal cyanides may be generated in situ in the reaction system.
The reaction can be carried out, for example, by the following method. 1U1
In a method called the tee method, anhydrous hydrogen cyanide is applied to the ketone while it is cold.

A trace amount of alkali cyanide is added to accelerate the reaction,
Increase yield. Note that the reaction at cold time has the meaning of suppressing the reverse decomposition of cyanohydrin. This method has the advantage that cyanohydrin can be easily isolated and purified. This is a method called the 2Urech method, in which a ketone is dissolved in an aqueous solution of cyanide, and then an inorganic acid such as sulfuric acid or hydrochloric acid is added.

In this case as well, it is preferable to carry out the reaction in the cold. 3 Sodium bisulfite adduct method.

This is a method in which cyanide is reacted with a sodium bisulfite adduct of a ketone. Since the reaction is carried out in alkaline conditions, no hydrogen cyanide is generated and there is little danger. 4 Method using ion exchange resin.

This method involves reacting a ketone with hydrogen cyanide using a sulfonic acid-based ion exchange resin as a catalyst, and the yield is high. The product of the cyanohydrination reaction can be separated from the reaction mixture and purified, but in the present invention, the product in the reaction mixture is directly dehydrated and solvolyzed in the presence of an acid to obtain the product of formula (■). Conversion to unsaturated carboxylic acids or esters thereof is advantageous.

The acid that acts as a dehydrating agent and a catalyst for solvolysis is suitably a strong inorganic acid such as sulfuric acid, hydrochloric acid, or lyso acid, and is usually used in an amount of about equimolar to about 3 times the molar amount of the cyanohydrination reaction product. It will be done. Dehydration and solvolysis reactions can be carried out by heating, but in consideration of controlling the reaction rate and reaction selectivity, the initial stage of the reaction is carried out at a relatively low temperature of room temperature to 100'C, and then the reaction is carried out at a relatively low temperature of 100 to 200'C. Preferably, the reaction is carried out at a relatively high temperature of .degree. It is assumed that dehydration and solvolysis proceed simultaneously. If this reaction is carried out in an aqueous system, an unsaturated carboxylic acid in which R in formula (■) is a hydrogen atom will be obtained as a reaction product, and if carried out in the presence of alcohol, a corresponding alcohol ester of the unsaturated carboxylic acid will be obtained. It will be done. The alcohol can be a primary, secondary and tertiary alcohol having 1 to 20 carbon atoms, such as methanol, ethanol, propanol, butanol, octanol, cetyl alcohol, octadecyl alcohol. The unsaturated carboxylic acid obtained in the above reaction is esterified into an unsaturated carboxylic ester, and the obtained unsaturated carboxylic ester is converted into another type of unsaturated carboxylic acid by re-esterification or transesterification after hydrolysis. It can also be converted into esters. The resulting unsaturated carboxylic acid of formula (■) or its ester is then hydrogenated to give the desired 2,4,6,8-tetramethyldecanoic acid of formula (1) or its ester.

This hydrogenation saturates the carbon-carbon unsaturated bond, and can be carried out by a method known per se that is suitable for that purpose. The reaction is generally carried out in the presence of a conventional hydrogenation catalyst such as palladium, platinum, Raney nickel, Raney cobalt, or silica alumina, in a solvent such as a hydrocarbon, alcohol, ether, ketone, ester, or carboxylic acid, at room temperature to 150 ℃. It is carried out at ℃. The reaction pressure is normal pressure,
Either pressurization may be used. The product can be derived into other esters by esterification, hydrolysis followed by esterification or transesterification, as described for the compound of formula (■). b 4,6,8-trimethyldecan-2-one of formula (■) used as a starting material in the present invention is a new compound, and it can be used in the following steps (1) to (
7). 1) 1-Hello 2-
A step of reacting butene with mesityl oxide and/or isomesityl oxide in the presence of an alkaline condensing agent.
The reaction product of this step is usually represented by the following formula (■) 3
-Isopropenyl-5-hepten-2-one and formula (■)
3-isopropylidene-5-heptene-2 represented by
- It is a mixture with on. [In the above formula, X is a halogen atom such as chlorine or bromine, and the dotted line indicates that a double bond exists at either of the positions indicated by this.] The above reaction is a reaction between ketones and organic halogens. This can be carried out by a known method of producing a substituted ketone by reacting the compound with 2 in the presence of an alkali condensing agent.

The alkaline condensing agent is preferably sodium amide, potassium amide, lithium amide, sodium hydroxide, potassium hydroxide, sodium alcoholate, potassium alcoholate, and is about equimolar to about 1 mol based on 1-halo-2-butene. It is preferably used in an equimolar to 4-fold molar amount. (2) The unsaturated ketone of the above formula (■) is expressed by the formula (■)
The desired step isomerization of to an un5-saturated ketone.

This step is performed as necessary. Expression (■) and Expression (■
) can be separated into each unsaturated ketone by precision distillation, and the isomerization reaction may be applied to the separated unsaturated ketone of formula (■), but in the present invention, a mixture of the two can be used. The unsaturated ketone of formula (■), which has a lower boiling point than the unsaturated ketone of formula (■), can be obtained by subjecting it to an isomerization reaction and then distilling it, or by distilling a mixture of both under isomerization reaction conditions. It is advantageous to recover efficiently and with high purity.

In the isomerization reaction, the unsaturated ketone of formula (■) is treated with an acidic catalyst such as oxalic acid, adipic acid, or phenolic acid or with 1,8-
Diazabishikuro [5, 4, 0] - Undesen - 7,
1,5-diazabicyclo[4.3.0]-nonescy 5, by heating in the presence of an organic amine catalyst such as triethylamine or hexamethylenetetramine, or by treatment with an aqueous or alcoholic solution of an alkali metal compound. can be done. 3) A step of rearranging the unsaturated ketone of formula (■) to 4●6-dimethyl-3●7-octadien-2-one represented by the following formula (■).

This rearrangement reaction can be carried out by heating the ketone of formula (■) to a temperature of 150 to 250°C, preferably 170 to 200°C under an inert gas atmosphere.

The ketone of formula (■) usually has a cis/trans isomer of about (10-20)/(90-80
), and it is difficult to separate the two by distillation.
It is subjected to the reaction in the form of a mixture. However, the cis form is 1
・Due to the 3-diaxial (DiaxiaI) effect, the formula (
Since it is difficult to rearrange to the ketone ((2)), the cis form may be isomerized to the trans form if necessary. 1) 4 and 6 of formula (■)
- A step of hydrogenating dimethyl-3,7-octadien-2-one to obtain a saturated ketone of the following formula (■).

This reaction can be carried out in the same manner as described above regarding the hydrogenation reaction of the unsaturated carboxylic acid of formula (■) or its ester. (5) A step of preparing an acetylenic alcohol represented by the following formula (V) by reacting the saturated ketone of the formula (■) with a halogenated propargyl di such as propargyl bromide or propargyl chloride.

The above reaction can be carried out in a dry solvent such as diethyl ether or tetrahydrofuran in the presence of metallic magnesium or metallic aluminum in an amount equal to or greater than the mole of the compound of formula (■).

Preference is given to reaction in an inert atmosphere. (6) A step of preparing an unsaturated ketone of the following formula (■) by hydrating and dehydrating the obtained acetylenic alcohol of formula (V).

For example, J. Am. Chem. SOc. , plate, 7
18 (1938), that is, by dehydrating and hydrating the acetylenic alcohol of formula (V) using sulfuric acid in the presence of an acidic catalyst such as mercuric sulfate in an alcoholic aqueous solution.

The dehydration reaction and the hydration reaction may thus be carried out simultaneously or separately. (7) A step of hydrogenating an unsaturated ketone of formula (■) to a saturated ketone of formula (■).

This reaction can be carried out in all the same manner as described for the hydrogenation of unsaturated carboxylic acids of formula (■) or esters thereof. 2・4・manufactured by the present invention
6,8-tetramethyldecanoic acid and its esters are
It is useful as a cosmetic base and cosmetic additive in the production of rinse solutions, creams, jumpers, soaps, etc.

Next, the present invention will be specifically explained with reference to Examples.

Example 1 (1) 3-isopropenyl-5-heptene-2
Preparation of -one 900 g of 1-chloro-2-butene and 1960 y of mesityl oxide were mixed in a 55% by weight aqueous solution of 600 Da of sodium hydroxide in the presence of 20 V of trimethylstearylammonium chloride at room temperature for 2 hours.
The reaction was carried out at ℃ for 1 hour.

The reaction solution was poured into water and extracted with ether. The extract layer was washed with water, dried, and then the solvent was distilled off under reduced pressure. According to gas chromatography analysis, the residue was 3-isopropenyl-5-hepten-2-one/3-isopropylidene-5-
It contained a 5/55 mixture of hepten-2-ones. This residue was crudely distilled to a boiling point of 72 to 100°C/25T.
973 g of the above mixture was obtained as a fraction of frffLHg. By precision distilling the fraction, 3-isopropenyl-5-hepten-2-one was produced with a boiling point of 83-85°C/25°C.
T! As a fraction of RmHg, 3-isopropylidene-5
- Hepten-2-one with a boiling point of 85-90℃/25wfm
It could be obtained as a Hg fraction. Next, 3-isopropenyl-5-hepten-2-one containing 21%
Isopropylidene-5-hepten-2-one 620y and 1,8-diazabicyclo [5●4
●0] 6.2y of -7-undecene was charged into a distillation column, the bottom temperature was 108-112℃, the top temperature was 89-90℃, and the degree of vacuum was 277177! Distillation was carried out under isomerization conditions while maintaining Hg, and 3-isopropenyl-5- with a purity of 98.8% was obtained.
Hepten-2-one 591y was obtained. The structure of the compound was confirmed by the following method. Infrared absorption spectrum (Nea
t) 1685.1612, 135011185s970 (C
Tn-1) Nuclear magnetic resonance spectrum (δi]!?P...

Ol4) 1.4 Ash 1.6 to 1.68 (Eachs..9
H. ．． CH3-) Member. --AJ1.92 (Eachs,.3ll..廿)
2.77(Eachs..2Hl-CH2-)Ca. 5
．． l9 (BrOads., 2Hl-CH=CH-) Infrared absorption spectrum (Neat) 1715, 1642, 1
34011379, 1355, 11601970190
0(Crfl-1) nuclear magnetic resonance spectrum (δso,.

CCl4) 1.49 (S..6H,.CH3-)
ShiFl3-shi- 1.89 (S..3H..ll.) Ca. l. 9O~2.40(M..?, -CH2-)2
．． 96(TllHl-7H-1J=7Hz)4.71(
S. ．． 2H>C=CH2)Ca. 5. l4, 5.18 (
M,,2lll-CH=CH-) The cis- and trans structures in 3-isopropenyl-5-hepten-2-one are shown in the carbon-B nuclear magnetic resonance spectrum (Ppm; InCDCl
3) was confirmed.

:2) 4,6-dimethyl-3,7-octadiene-2-
400y of 3-isopropenyl-5-hepten-2-one obtained in (1) above was heated under a nitrogen atmosphere with an oil bath temperature of 200±2°C and an internal temperature of 188 to 197°C.
A rearrangement reaction was carried out by heating for 1 hour.

The reaction solution was precisely distilled as it was, and the boiling point was 60℃/5.0wr.
! Cis/trans mixture of raw materials as NH-like fraction 3-
A mixture of 247y of isopropenyl-5-hepten-2-one and a part of the product, Δ3-cis, 4,6-dimethyl-3●4-octadien-2-one, was recovered and had a boiling point of 57±1°C/4.0TWLHg. As a fraction Δ3-trans, 4,6-dimethyl-3,7-octadiene-2
137.6y of -one (purity 94%) was obtained. The structure of this product was confirmed by the following method. Infrared absorption spectrum (Neat) 168 1615, 1359, 1351, 1213, 1
165 (C7n-Li nuclear magnetic resonance spectrum (δKichi PmC
Cl4)0.8 1.94 (S..4, CH3-)2.
00, 2.03 (S..6H..CH3-, carbon-13
Nuclear magnetic resonance spectrum (Ppm; InCDCl3) 1-
113.66-125.62-143.77-198.
7 3-36.28-20.3 4-49.09-19.7 5-156.8@-32.2 (3) Production of 4●6-dimethyloctan-2-one Method (2) above 75q of 4,6-dimethyl-3,7-octadien-2-one obtained in 300ml of n-hexane
2% palladium-carbon 3y as a catalyst, 1
Under hydrogen pressure not exceeding 0k91cIL, reaction temperature 50°C
The hydrogenation reaction was carried out at

After the reaction, the catalyst was removed and the mother liquor was concentrated under reduced pressure to obtain 74.6y of a colorless liquid, which was distilled under reduced pressure to a boiling point of 89-90.
4◆6 of 72.1y as a fraction of 0C/21TwLHg
-dimethyloctan-2-one was obtained. The structure of this product was confirmed by the following method. Infrared absorption spectrum (N
eat) 171 & 1461, 1377, 1360, 1168 (C
ln-1) Nuclear magnetic resonance spectrum (δsoP.nCCl4
)N79n7 et al.N7λn-only A(z.QH-CHu)(
4) Production of 4●6,8-trimethyldecane-1-yn-4-ol To 11y of metallic magnesium in 150ml of dry ether and 0.7y of mercuric chloride was added to the mixture, under a nitrogen gas atmosphere, the above (3) ) obtained by 4・6−
A solution of a mixture of 70.0y of dimethyloctan-2-one and 53.6f of propargyl bromide dissolved in 350ml of ether was added dropwise under reflux to carry out the reaction.

After the addition, the mixture was refluxed for an additional hour, and then the reaction mixture was poured into an acetic acid aqueous solution, extracted with ether, washed with water, and dried.
After distilling off the solvent from the extract layer under reduced pressure, 75.8y of 4,6,8-trimethyldecane-1-yn-4-ol was obtained as a fraction with a boiling point of 68-69 layer C/0.2710 nHg. The structure of this product was confirmed by the following method. Infrared absorption spectrum 3440, 3300, 2120, 1463s1378,
114 & 635 (Cm-Li nuclear magnetic resonance spectrum (δW
, mCCl4)Ca. O. 76, 0.83, 0.88,
0.94 (M..9H..CH3-) 1.17 (S..
3H. ．． CH3-) Ca. l. OO~1.80 (M..8Hlca.l.8
4, 1.90 (Ml2Hl-CH2-) 2.21, 2.
24 (S., 2Hl-0H1-C...CH) (5) 4・6
・Production of 8-trimethyl-3-decen-2-one 300
30% aqueous methanol 90T in a 3 m1 flask
fLt1 Mix 1 y of mercury sulfate and 0.6 V of sulfuric acid, and add 20 ml of 30% aqueous methanol solution of 58.8 y of 4,6.8-trimethyldecane-1-yn-4-ol obtained in (4) above under reflux. was dripped.

After dropping, reflux for 24 hours! ! The reaction was carried out for 1 hour, and gas chromatography (PEG2OMll50°C) analysis confirmed that the raw materials had disappeared and that two new peaks appeared at positions with short retention times, and then the reaction was terminated. After neutralizing the reaction solution with sodium hydrogen carbonate, methanol was distilled off under reduced pressure, and the residue was extracted with ether, washed with water, and dried. The solvent was removed from the ether layer and the residue was vacuum distilled to a boiling point of 130.
~・137℃/22Tn! 49.6 as a fraction of NHg
4,6,8-trimethyl-3-decen-2-one of y was obtained. The structure of this substance was confirmed by mass spectrometry and infrared absorption spectroscopy (Neat; 1680, 1912, 1462, 1
37 & 1215, 1165 Sono Ichiri and nuclear magnetic resonance spectra. (6) Production of 4◆6●8-trimethyldecan-2-one By the same method as in (3) above, the above (
The 4,6,8-trimethyl-3-decene,12-one 45y obtained by the method 5) was hydrogenated using 2% palladium on carbon, and the same treatment reduced the boiling point to 74-76°C/0.
．． 43.6y of 4.6●8-trimethyldecan-2-one was obtained as a fraction of 3TWLHg.

The structure of this substance was confirmed by mass spectrometry [m/e=,1
9PFs13ku130116\151,140], McIafferty conversion peak specific to ketone [M]4-5
8=140 was confirmed, and the infrared absorption spectrum (Neat; 171den 1462, 1378Fs136
Confirmed by H.1165 analysis and nuclear magnetic resonance spectroscopy. (7) Production of methyl 2,4,6,8-tetramethyldecanoate 40y of 4,6,8-trimethyldecan-2-one obtained in (6) above was mixed with 11 potassium cyanide.
．． After adding 7y to a solution of 50 mt of water, 30% sulfuric acid 66y was added dropwise while keeping the reaction temperature below 20°C.

Next, potassium carbonate was added to neutralize the mixture, and after reaching the neutralization point, 5y of potassium carbonate was further added to salt out the product, followed by ether extraction. The ether was distilled off from the extract layer to recover 41.3y of crude cyanohydrin, which was dissolved in concentrated sulfuric acid 3
2y was added little by little. At this time, since a considerable amount of heat was generated, the reaction was carried out in a water bath and the temperature was maintained at 60 to 70°C. Next, the reaction temperature was raised to about 150° C. to continue the dehydration and hydrolysis reactions, and after further cooling, 100 ml of methanol was added and the reaction was carried out under reflux for 3 hours. After neutralizing the reaction mixture with sodium hydrogen carbonate, methanol was distilled off under reduced pressure, poured into water, and extracted with ether. Distill the extract layer to boiling point 88-95℃/0.3TmH
methyl 2-methylene-4,6,8-trimethyldecanoate and 2,4,6,8-tetramethyl-2 as fractions of g.
-34.2 g of a mixture of methyl decenoate was obtained. The mixture was subjected to a hydrogenation reaction in the same manner as in (3) above, with a boiling point of 87-90°C/0.377!77! As a fraction of Hg 2
・Methyl 4,6,8-tetramethyldecanoate 33.6y
I got it. This includes infrared absorption spectrum, mass spectrometry,
The structure was confirmed by nuclear magnetic resonance spectroscopy. ))2・4
・Production of 6,8-tetramethyldecanoic acid octadecyl ester Methyl 2,4,6,8-tetramethyldecanoate 3y obtained in (7) above and octadecyl alcohol 5q
The mixture was heated under reflux in 30 ml of toluene in the presence of 0.1 y of potassium hydroxide, and the transesterification reaction was carried out while constantly distilling off methanol by-produced outside the reaction system.

Claims (1)

[Claims] 1. 4,6,8-trimethyldecan-2-one represented by the following formula (III) ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (III) is subjected to a cyanohydrination reaction, and the product is The following formula (II) obtained by dehydrating and solvolyzing in the presence of an acid ▲ mathematical formula, chemical formula,
There are tables, etc. ▼Unsaturated carboxylic acid or its ester represented by (II) represents a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms].
I) ▲ Numerical formulas, chemical formulas, tables, etc. ▼ Method for producing 2,4,6,8-tetramethyldecanoic acid or its ester represented by (I) [R in formula (I) is as defined above. ]. 2 4,6,8-trimethyldecane-2- of formula (III)
A method for producing 2,4,6,8-tetramethyldecanoic acid or an ester thereof according to claim 1, wherein 1 is prepared by the following steps. (1) The following formula (VI) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ Process of Grignard reaction of 4,6-dimethyloctan-2-one represented by (VI) and propargyl halide (2) The following is obtained Formula (V)▲There are mathematical formulas, chemical formulas, tables, etc.▼(V
) The process of hydrating and dehydrating the acetylenic alcohol represented by (3) the following formula (IV) produced ▲There are mathematical formulas, chemical formulas, tables, etc. ▼4,6,8-trimethyl-3 represented by (IV) - A step of hydrogenating decen-2-one. 3. 2,4,6,8-tetramethyldecanoic acid or 2,4,6,8-tetramethyldecanoic acid according to claim 2, wherein 4,6-dimethyloctan-2-one of formula (VI) is prepared by the following process. A method for producing the ester. (1) A step of reacting 1-halo-2-butene with mesityl oxide and/or isomethyl oxide, (2
) The following formula (VIII) is obtained ▲ Numerical formulas, chemical formulas, tables, etc. are available ▼ Step of rearranging 3-isopropenyl-5-hepten-2-one represented by (VIII), (3) The following formula (VII) is obtained. ) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ A process of hydrogenating 4,6-dimethyl-3,7-octadien-2-one represented by (VII).