JPS5829766B2 - Crocetan production method - Google Patents

Description

[Detailed description of the invention] The present invention relates to a method for producing crosetan.

Crocetan is a compound represented by the formula % and has extremely good affinity with the skin, so it can be used as a base material for cosmetics or as an additive for cosmetics, external medicines, etc.

Furthermore, since its melting point is extremely low, it is a useful substance as a lubricating oil in a low temperature range.

Furthermore, it is also useful as a plasticizer for polymers.

Currently, crosetan is not thought to be produced industrially, but a few methods for its synthesis are known.

One of them is to reduce citral to tetrahydrogeraniol, convert this into tetrahydrogeranyl bromide with a brominating agent, and further combine this with metallic potassium and Wurz (Wu).
r tz ) is a method of reacting to obtain crosetan.

(N, A, 5orensen et aLActaCh
em, 5cand, 2.140 (1948))
.

This method requires the use of extremely dangerous and expensive reagents such as metallic potassium, and is not suitable for industrial large-scale production.

Furthermore, a method to obtain crosetan by hydrogenating digeranil is known (J, Pliva et al.
ActaChem-5cand, +±, 846 (195
0);N,A.

5orensenetal+ 1bid 5.757
(1951): M, 5oucek et al.
Co11ection Czechoslov-Che
m, Corrmuns-, 26, 2551 (1961)
].

Digeranil, which is a raw material, is obtained from geranyl bromide by a Wurtz-type reaction similar to tetrahydrogeranyl bromide using metal magnesium, and Digeranyl by Sousek et al. is obtained by separating it from helgamot oil.

The method of obtaining crosetan from bergamot oil is too small and expensive for industrial production, and the method via geranyl bromide also requires a large amount of magnesium metal.
This is not a desirable method.

Also, P. Karrer et al.
M, Acta, 35.1494 (1962)] synthesized crosetan by removing the hydroxyl group from 1.20-dihydroxycrothecune using a brominating agent; It's not clear how to get there.

The present inventors have conducted repeated research on an industrially advantageous method for producing crosetan, and as a result, have arrived at the present invention.

That is, according to the present invention, an acenalene alcohol represented by general formula (I) or a mixture thereof is subjected to an oxidative coupling reaction to form acenalene alcohol represented by general formula (I) [wherein two R are mutually is the same or different and has the above meaning] and is hydrolyzed as is (directly) or hydrogenated to form an unsaturated compound having no triple bond or represented by formula (10) 6, 11-
Crocetan can be easily obtained by converting it into dihydroxycrocecne and then hydrolyzing it, or by dehydrating the 6,11-dihydroxycrocecne and then hydrogenating it.

Among the raw materials used in the present invention, that is, the compounds represented by the general formula (I), dehydrolinalool (II) is an intermediate for the production of synthetic vitamins A and E or their raw materials, linalool and citral, and is currently not available industrially. It is manufactured in large quantities.

Furthermore, 3,7-dimenaloct-7-en-1-y can be produced industrially at low cost by the following synthesis method.

That is, acetone, imbutylene and trioxane are reacted to obtain 6-methyl to but-6-en-2-one (
For this reaction see German Patent No. 1 268 135 of HoPOmmer et al),
This can be obtained by ethynylation reaction with acetylene.

Furthermore, 3,7-daminaloct-1-yn-3=ol (I-I[1) is 6-methylhebut-5-en-2-one, which is a raw material for dehydrolinalool (I-1), or the above 6- By hydrogenating but-6-en-2-one to methyl, 6-
It can be easily obtained by preparing menalhebutan-2-one and then subjecting it to an ethynylation reaction with acetylene.

The method of the present invention is extremely superior to conventional methods for synthesizing crosetan in terms of the required raw materials, the reaction yield in each manufacturing step, and the simplicity of the manufacturing process.

Next, each step of the method of the present invention will be explained in detail.

(A) 2,6,11,15-tetramethylhexadeca-
2,14-diene-7,9-diyne-6゜11-diol (kawa-1); 2,6,11゜15-tetramethylhexadeca-1,15-diene-7,9-diyne-6, 11
-Production of diol (n-n) and 2,6,11,15-tetramethylhexadeca-7,9-diyne-6,11-diol (n-m) 2,6, 11゜15-Tetramethylhexadeca-2,14-diene-7,9-diyne-6,11-diol (ni) is a new compound, dehydrolinalool (3,7-dimethyloct6-ene- It can be produced by subjecting 1-yn-3-ol (1-I) to an oxidative coupling reaction.

2,6゜11.15-tetramethylhexadeca-1゜1
5-diene-7,9-diyne-6,11-diol (I
fl) and 2,6,11.15tetramenalhexadeca-7,9-diyne-6°11-diol (It-I
[I) is also a new compound, and in the same way, 3,
It can be produced from 7-dimenaloct-7-en-1-yn-3-ol (1-l) and 3,7-dimethyloct-1-yn-3ol (I-1).

In this oxidative coupling reaction step, a wide range of known oxidative coupling reaction methods for acetylene compounds can be applied.

Examples of general oxidative coupling reaction methods suitable for use in the present invention include methods (1), (2), and (3) below.

(1) A monovalent copper salt and ammonium chloride are dissolved in water, a compound represented by general formula (I) or a mixture thereof is added, and the mixture is reacted in air or oxygen atmosphere to obtain the desired product.

In this case, the reaction solvent water is ethanol, acetone,
It is more effective to use a mixed solvent with an organic solvent that mixes with water, such as tetrahydrofuran.

(2) A monovalent copper salt is dissolved in an amine solvent such as pyridine, picoline, or triethylamine, and raw material acetylene alcohol is added to the solution and reacted in an air or oxygen atmosphere.

(3) The above (2) using divalent copper salt:! : Obtain the desired product in a similar manner.

Among these methods, the particularly preferred method is method (2) or (3), in which a catalytic amount of the copper salt is sufficient.

When carrying out the reaction by this method, the copper salt is preferably a cupric carboxylate such as cuprous chloride and cupric acetate.

Furthermore, the solvents used are not only amine solvents such as pyridine, picoline, and triethylamine, but also all organic solvents.
For example, hydrocarbons, halogenated hydrocarbons, alcohols, ethers, ketones, esters, dimenalformamide, dimethyl sulfoxide, etc. can be used.

In this case, it is essential to use pyridine, picoline, triethylamine, etc., but it is sufficient if these are used at least 10 times the mole of the catalyst.

Preferred are tertiary amines such as pyridine, picoline, triethylamine.

In this case, the reaction may be carried out at room temperature to 100°C.

(B) 2,6,11,15-tetramethylhexadeca-2,14-diene-7,9-diyne-6゜1
1-diol (I[-I): 2,6,11゜15-tetramethylhexadeca-1,15-diene-7,9-diyne-6,11-diol (n-n) and 2,6,
1.1 Hydrogenation reaction of 1,15-tetramethylhexadeca-7,9-diyne-6,11-diol (n-■).

In carrying out the hydrogenation reaction of the above-mentioned compound according to the present invention, a conventional hydrogenation reaction can be employed.

Regarding the method for obtaining 6,11-dihydroxycrocetane from the compound represented by general formula (II), as a catalyst,
Examples include nickel, cobalt, palladium, platinum, rhodium, iridium, ruthenium, osmium, etc. Among these, the most common ones are Raney nickel, nickel supported on diatomaceous material (hereinafter abbreviated as lNi-diatomy material) ), palladium supported on activated carbon (hereinafter abbreviated as lPd-carbon, etc.), and any of them can be preferably used.

Depending on the reaction conditions during this reaction, a hydrolysis reaction may occur,
A mixture of 6-hydroxycrocetane or crosetane with 6,11-dihydroxycrocetane, which is the desired by-product, may be obtained in some cases, but such a mixture may be carried into the next step as is.

When the purpose is to obtain only 6°11-dihydroxycrocetane, it is necessary to select reaction conditions.

In order to avoid inducing a hydrolysis reaction during the hydrogenation reaction, it is generally preferable to select the following conditions.

That is, as for the catalyst, it is preferable to use one having basicity such as a Raney type catalyst.

It is preferable to avoid acidic and highly polar reaction solvents, and it is preferable to use saturated hydrocarbons, saturated ethers, saturated esters, etc. that do not change during hydrogenation.

The reaction temperature is also greatly affected; generally, lower temperatures are better, and temperatures of about 60°C to 150°C are preferred.

If the hydrogenation reaction is performed in a solvent with extremely high acidity or polarity, a cyclization reaction may occur, making it difficult to ultimately obtain high-purity crocetane.

The method of partially hydrogenating the compound represented by general formula (II) to obtain an unsaturated diol that does not have at least a triple bond allows the hydrogenation reaction to be carried out under milder conditions than the above hydrogenation reaction. has advantages.

In general, the hydrogenation reaction is easiest for triple bonds, and trisubstituted olefins are easier to perform than benisubstituted olefins.

When a compound represented by the general formula (II) is subjected to a hydrogenation reaction under extreme conditions or under conditions where a hydrolysis reaction is extremely likely to occur, a cyclization reaction often occurs, making it difficult to obtain highly pure crosetan.

It has been found that such side reactions do not occur if the triple bond of the compound represented by the general formula (II) is hydrogenated and the partially hydrogenated reaction product is subjected to a hydrolysis reaction.

When Crocetane is finally obtained by a hydrolysis reaction, the remaining unsaturated bonds are easily hydrogenated under the conditions of the hydrolysis reaction, so if such side reactions do not occur, the hydrogenation reaction in the previous step is not possible. It is not necessary to hydrogenate all unsaturated bonds.

As a catalyst for such a partial hydrogenation reaction, those mentioned above can be used as catalysts that can be used to obtain hydroxycrocetane from the compound represented by the general formula (If). A Pd-supported catalyst having a strong activity under certain temperature conditions and having a small amount of Raney nickel supported is preferable from an economic point of view.

The reaction temperature is preferably room temperature to about 100°C.

6. Hydrogenating the compound represented by general formula (II);
The hydrogenation reaction of unsaturated crocetane obtained by dehydrating 11-dihydroxycrocetane is exactly the same as the hydrogenation reaction of 6.11-dihydroxycrocetane from the compound represented by general formula (I). I can do it.

For any hydrogenation reaction, a hydrogen pressure of 100 kg/criL or less during the reaction is sufficient, and normal pressure is also possible.

Since the compounds to be subjected to the hydrogenation reaction step, such as the compound represented by the general formula (n) and the dehydration reaction product of 6,11 dihydroxycrocecne, have extremely high viscosity, the hydrogenation reaction is preferably carried out in a suitable solvent.

Preferably used solvents include saturated hydrocarbons, saturated ethers, saturated alcohols, and saturated esters.

? ) 6. Production of unsaturated crocetane by dehydration reaction of 11-dihydroxycrocetane A hydrogenated product of the compound represented by general formula (1) is subjected to a dehydration reaction to dehydrate the tertiary hydroxyl group present in the molecule of the compound. do.

In this case, catalysts that can be used for the dehydration reaction are: (a) Brønsted acids, such as sulfuric acid, hydrochloric acid, phosphoric acid, perchloric acid, boric acid, etc. (b) Lewis acids, such as zinc chloride, aluminum chloride, Boron mifutride, tin tetrachloride, etc. (c) Acidic salts of strong acids and strong bases, such as sodium hydrogen sulfate, sodium hydrogen phosphate, potassium hydrogen sulfate (d) Salts of strong acids and weak bases, such as magnesium sulfate, sulfuric acid Zinc, calcium sulfate, copper sulfate, magnesium chloride, etc. (e) Solid acids, such as silica-alumina, alumina, solid phosphoric acid, kanaone exchange resins, etc.

The reaction can be carried out in the presence of such a catalyst without a solvent or by dissolving the hydrogenation reaction product in an appropriate solvent.

For example, when a mineral acid such as sulfuric acid or phosphoric acid, a Lewis acid such as zinc chloride or aluminum chloride, or a solid acid such as a cation exchange resin is used as a catalyst, it is preferable to use a hydrocarbon, -alcohol, ether, or ketone. Dehydration can be carried out quantitatively in organic solvents such as organic solvents or in the absence of solvents under mild conditions at temperatures below 200°C.

On the other hand, when a solid acid such as alumina, silica-alumina, or activated silica is used as a catalyst, it is desirable to carry out the reaction at a temperature in the range of 150 to 300° C. in order to perform dehydration in a short reaction time.

The dehydrated product thus obtained can be converted to crocetane by hydrogenation under the same conditions as the hydrogenation reaction in (B) above.

(D Production of crosetane by the hydrolysis reaction of a compound represented by the general formula (1), a product obtained by partially hydrogenating said compound, and 6゜11-dihydroxycrocecne Hydrolysis reaction in the method of the present invention This can be carried out at high temperatures by adding acidic substances such as those used in dehydration reactions to a conventional hydrogenation reaction system.

Catalysts that can be used for the hydrolysis reaction are nickel,
Examples include metals such as palladium, platinum, rhodium, and iridium, compounds thereof, or catalyst components thereof supported on a suitable carrier.

The hydrolysis reaction using these catalysts can be carried out by various methods such as those described below.

(1) Method carried out in an organic carboxylic acid The carboxylic acids used include acetic acid, propionic acid, butyric acid,
Isobutyric acid and the like are preferred.

These carboxylic acids may be used in combination with other highly acidic carboxylic acids such as α-halogen fatty acids and α-oxy fatty acids.

(2) Method carried out in the presence of an acidic substance in an inert organic solvent The organic solvent used is a saturated hydrocarbon such as hexane, heptane, cyclohexane, ethylcyclohexane,
Preferred are decalin, squalane, or crosetane, which is the object of the present invention.

Depending on the reaction conditions, aromatic hydrocarbons, cyclic ethers, esters, ketones, alcohols, especially tertiary alcohols, etc. can undergo reactions such as hydrogenation, ring opening, hydrolysis, and dehydration. It is desirable to avoid use under conditions that cause

Acidic substances include (a) Brønsted acids such as sulfuric acid, hydrochloric acid, phosphoric acid, perchloric acid, boric acid, etc. (b) Lewis acids such as zinc chloride, aluminum chloride, boron trifluoride, etc. (c) Strong acids and strong bases Acid salts such as sodium hydrogen sulfate, sodium hydrogen phosphate, potassium hydrogen sulfate, etc. (d) Salts consisting of strong acids and weak bases, such as magnesium sulfate, zinc sulfate, calcium sulfate, copper sulfate, magnesium chloride, etc. (e) Solid acids, e.g. Silica alumina, solid phosphoric acid, etc. and (f) organic carboxylic acids such as acetic acid, formic acid, monochloroacetic acid, lactic acid, etc. are effective.

When carrying out a hydrolysis reaction by the method described above, the combination of a hydrogenation catalyst and an acidic substance, or the combination of a catalyst, an acidic substance, and a solvent is particularly important if the catalyst is partially poisoned by the acidic substance or solvent. It is preferable to use a combination system that does not dissolve.

For these reasons and the fact that industrially economical catalysts can be used, a particularly preferred hydrolysis method is (a) a nickel or palladium catalyst supported on a carrier, such as a nickel catalyst supported on a diatomer;
A method of hydrolysis in the presence of a palladium catalyst supported on activated carbon and in the coexistence of a salt consisting of a strong acid and a weak base or a solid acid without a solvent or in an inert organic solvent.

(b) Hydrolysis in an organic carboxylic acid or a mixed solvent of an organic carboxylic acid and an inert organic solvent that is stable in the organic carboxylic acid in the presence of a palladium catalyst supported on a carrier such as activated carbon. be.

When carrying out the hydrolysis reaction by these methods, the hydrolysis reaction can be carried out in a liquid phase at an elevated temperature.

The reaction temperature is approximately 100°C or higher, especially 15°C, considering the reaction rate.
0 to 200°C is preferred.

Regarding hydrogen pressure, this reaction can be carried out under normal pressure, but in order to increase the reaction rate, it is preferable to carry out the reaction under hydrogen pressure, and a hydrogen pressure of about io to 100 kg/criL (gauge pressure) is usually used. Re: Ru.

The amount of catalyst used depends on the type of catalyst used, but can generally vary within a wide range, such as about 0.1 to 10% by weight based on the raw material.

As mentioned in section (B), when the compound represented by the general formula (If) is hydrolyzed, a cyclization reaction may occur and high purity crocetane may not be obtained.

However, it is possible to obtain highly pure crosetan by directly hydrolyzing the compound represented by the general formula (Kawa) by selecting reaction conditions.

These reaction conditions can be achieved by making the hydrogenation reaction rate extremely high compared to the apparent dehydration reaction rate.

Such conditions depend on the hydrogenation catalyst used, the acidic substance, their ratio, and the reaction temperature.

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

Example 1: 3,7-dimethyloct6-en-1-yn-8-ol (tehydrolinalool) ioo in a round bottom flask
, p1 ammonium chloride 264.9° cuprous chloride 165
g and 660 ml of water were added, and the mixture was stirred vigorously at room temperature while blowing oxygen, and reacted for 24 hours.

After the reaction, 600 rIL of benzene was added to the reaction mixture, which did not contain any raw materials, and the mixture was stirred.The entire reaction mixture was centrifuged to remove the solid matter, and then separated, and the organic layer was evaporated to produce the desired product. 74.4 g of product was obtained.

Dissolve this substance 11 in 50ml of benzene and 1g of activated carbon.
was added, stirred overnight at room temperature, and then filtered.

Furthermore, benzene was completely removed by distillation.

7.2 g of a very viscous pale yellow liquid was obtained.

The elemental analysis values for this product are as follows.

HO Theoretical value* 79.42 10.00 10.58 Measured value 78.56 9.72 10.28*However, the theoretical value is 2,6,11,15 Tetramethylhexadeca-2°14-diene-7,9 Table 1 shows the 13C-NMR spectrum of -diyne-6,11-diol.

The freezing point was ~14 to -15°C.

From the elemental analysis 13C-NMR and the synthesis of 6,11-dihydroxycrocecne and crosetane from this product shown below, this product is 2,6゜11.15-tetramethylhexadeca-2,14-diene-7, 9-diyne-
It is clear that it is a 6,11-diol.

3 out of 74.4g of the above oxidative coupling reaction product
Dissolve 0 g in 100 yd of butyl alcohol and add 5% Pd.
8 g of /C was added and reacted at room temperature for 24 hours while blowing hydrogen under normal pressure.

The catalyst was removed from the reaction product, and n-butyl alcohol was distilled off by simple distillation.

The desired product is 178-179°G/0.52 mm
Distilled with Hg.

Distillate amount: 25.6.9° This product can be recrystallized with n-hebutane.

The melting point after recrystallization was 81-82°C.

The elemental analysis values are shown below.

CHO Theoretical value 76.37 13.46 10.17 Measured value 76-47 13.59 10.69 Also, the 1''C-NMR spectrum of this product is shown in Table 2.

From the elemental analysis values, 13C-NMR spectrum, and the synthesis of crosetan from this product shown below, this product is 6,
It is clear that it is 11-dihydroxycrocecne.

Next, 1 g of anhydrous zinc chloride was added to 20 g of 25.6 g of the hydrogenated product, and a dehydration reaction was carried out at 150° C. for 30 minutes.

Add n-butane 100- to dissolve the reaction mixture, and n-
- The hebutane solution was washed repeatedly with water.

Furthermore, 2 g of 5% Pd/C was added to the obtained n-hebutane solution, and a hydrogenation reaction was carried out at 50° C. under a hydrogen pressure of 5 to 10 −/m.

After the reaction, Pd/C was removed, and n-hebutane was distilled under reduced pressure.

Main distillate boiling point 127-136°c/o, 38mm
Hg (literature value 144-155℃/2. OmmHg
N,A,58rensenet al,ActaC
hem-5cand-t 2 t 140 (1948)
)90 n 1.4412 (literature value n201.4431.1
．． 4406P.

D D Karrer et at, He1v, Chim, A
cta, 35, 14945 (1962), freezing point -108-1100C, d 25
0.783 (literature value 0.792.0.789 P, K
arreretal.

He1v, Chim, Acta, 35, 1494
(1962) ), J., Pliva et al., A.
cta, Chem, 5cand・, 4.

846 (1950)), and the physical property values show good agreement with the literature values.

In addition, the result of M s s analysis [M] 10-282 is given,
Its spectral pattern is consistent with crosetan.

Table 3 shows the C-NMR spectrum of crosetan obtained.

Table 3 Example of 13C-NMR spectrum of Crocetane
2 3,7-dimethylocta7 in a 21 three neck round bottom flask
-en-1-yn-3-ol15. 10 g of cuprous chloride, and 1400 mA of pyridine were added, and the mixture was reacted at 50 to 60° C. for 3 hours in an oxygen atmosphere.

After the reaction, no raw alcohol was present.

Pyridine was distilled off from the reaction system and benzene 300rfL1
The organic layer was washed with a 3N aqueous sulfuric acid solution and then with distilled water, and benzene was distilled off to obtain 10.3 g of a viscous liquid.

This product, n-hebutane 50-1, was placed in a 100 ml autoclave containing silica alumina 0.05. ! il', add nickel-diatomite catalysts o, s, p with a nickel content of about 5070 to 200~2
Hydrolysis reaction was carried out at 30°C for 16 hours.

The reaction mixture was subjected to gas chromatography (hereinafter referred to as "GLC").
It was identified as crosetan obtained in Example 1 by the method (abbreviated as ) and was consistent with the crosetan obtained in Example 1.

The yield of Crocetan analyzed by GLC was 7.63.
! It was li+.

Example 3 Oxidative coupling was carried out in the same manner as in Example 2, using 3゜7-dimethyloct-yn-3-ol as a raw material instead of 3,7-dimethyloct-7-en-1-yn-3-ol. reaction, followed by hydrolysis reaction to produce Crocetane 6.5
8 g (GLC analysis) was obtained.

Example 4 32.7 g of cupric acetate, 1 part of pyridine in a 51 round bottom flask
45 ml, n-hebutane 21. Dehydrolinalool 9
In addition to 13 g, oxygen was blown into the mixture while stirring, and the reaction was carried out at 60 to 80° C. for 8 hours.

After the reaction, it was washed several times with a 3N aqueous sulfuric acid solution and then with water.

N-hebutane was distilled off from the obtained n-hebutane solution.
287 g of crude product was obtained.

2゜6.11,15-tetramethylhexadeca-2゜14-diene-7,9-diyne-6,11- in the crude product
The concentration of diol was analyzed by liquid chromatography and was found to be 61.4%.

402 g of this crude reaction product, 200 ml of n-heptane.
Then, 30 g of Raney nickel was placed in an autoclave, and the hydrogen pressure was adjusted to 50 to 100 liters.

The reaction was carried out at ℃ for 8 hours.

The reaction wave catalyst was filtered, and n-hebutane was distilled to obtain 263 g of a crude reaction product.

The product analyzed by GLC is mostly 2°6.1
A peak that is 1,15-tetramethylhexadecane-6°,11-diol, which is considered to be monohydroxycrocecne, and crosetan were hardly observed.

21, n-hebutane 40 vertical in 263 g of crude reaction product,
Acetic acid 5TJ11 15% Pd/CO, 5 g io.

-Hydrogen pressure in autoclave: 80-100kg/i1
Hydrolysis reaction was carried out at 230°C for 16 hours.

The amount of crocetane produced after the reaction is 15. :l.

Example 5 In 263 g of crude 2,6,11,15-tetramenalhexadecane-6-11-diol obtained in Example 4, 20
g, n-hebutane 40rrL11 0.5g of the silica-alumina catalyst and 0.5g of the nickel-diatomite catalyst used in the hydrolysis reaction of Example 2. ! 7 was placed in an autoclave and reacted for 6 hours at a hydrogen pressure of 80 to 100 kg/ci and a reaction temperature of 230°C.

The amount of crosetan produced was 15.0 g.

Example 6 Hydrolysis was carried out in exactly the same manner as in Example 5, using 1 g of magnesium sulfate instead of the silica alumina as the hydrolysis catalyst.

The amount of crosetan produced was 5.6 g.

Example 7 In 1287 g of the crude product obtained by the oxidative coupling reaction of Example 4, 403.9. n-hebutane 200m
30 g of No. 11 Raney nickel was placed in a No. 11 autoclave, and a hydrogenation reaction was carried out at room temperature under a hydrogen pressure of 50 to 100 kg/criY.

During the reaction, the internal temperature of the autoclave reached 50-60'C.

After 3 hours, the reaction was stopped, the catalyst was filtered, and n-hebutane was distilled off to obtain 286 g of a crude product.

According to the 13C-NMR spectrum, this product had no triple bonds and only double bonds remained.

The iodine value was 123.8.

20 g of this crude product, 40 TrL of n-hebutane, 11 ml of silica alumina, which is the hydrolysis catalyst used in Example 2, and 0.5 g of silica alumina, which is the hydrolysis reaction catalyst used in Example 2. ! 9. Nickel-diatomy catalyst 0.5 to 10
0ml autoclave, hydrogen pressure 80-100kg
/i, reaction temperature was 230'C for 16 hours.

Claims (1)

[Scope of Claims] 1. A compound represented by the general formula (I) in which the two R's are the same or different and have the above meanings], which is directly hydrolyzed or hydrogenated. A method for producing crocetane, which comprises adding the compound to form an unsaturated compound having no triple bond or 6,11-dihydroxycrocetane, followed by hydrolysis. 2 (representing the general formula <1)] or a mixture thereof is subjected to an oxidative coupling reaction to form the general formula (1) [wherein the two R's are the same or different, and the above A compound represented by
-dihydroxycrocetane, and the method for producing crocetane is characterized in that the 6.11-dihydroxycrocecne is dehydrated and then hydrogenated.