JPH0334952A - Production of cis-3-hexenal dialkyl acetal and cis-3-hexenal - Google Patents

Abstract

PURPOSE:To easily obtain the title compound which is useful as a perfume substance with no use of expensive substances by catalytic hydrogenation of 2,4-hexadienal dialkyl acetal in the presence of a catalyst. CONSTITUTION:2,4-Hexadienal dialykyl acetal of formula I (R<1>, R<2> are lower alkyl or incorporate to form a lower alkylene) is used as a starting substance to effect catalytic hydrogenation using a metal carbonyl of formula II (M is a metal atom selected from Cr, Mo, W; arene is arene ligand; X is 1, 2; Y is 3 to 6; Z is 0 or 1 to 3) or an arene complex as a catalyst, preferably in an inert organic solvent such as methanol at room temperature to 230 deg.C, preferably at 40 to 200 deg.C under an appropriate pressure to give the compound of formula III. The subsequent hydrolysis gives cis-3-hexenal.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a method for producing cis-3-hexenal dialkyl acecool and cis-3-hexenal.

(Prior Art) Cis-3-hexenal has been known to be a compound useful as a fragrance substance because it has a strong green leaf-like aroma, and methods for its synthesis have been actively researched.

For example, a method is known in which cis-3-hexenol is oxidized with a chromium trioxide-pyridine-dichloromethane system or a dimethyl sulfoxide-dicyclohexyl sulfodiimide phosphorus pentoxide system to obtain cis-3-hexenal in good yield. (to griculturaland old o1ologic
al Chemistry,, 39 (])+
243-247.1975). However, the former reaction system produces a large amount of chromium waste, and is difficult to implement industrially due to the use of a large amount of solvent and separation operations. Furthermore, in the latter reaction system, there are problems with the use of expensive reaction reagents and the recovery of a large amount of dimethyl sulfoxide, and furthermore, the use of dimethyl sulfoxide is undesirable in the production of perfume substances due to its odor.

In addition, Witti (H
A method of deriving cis-3-hexenal through a reaction (Japanese Unexamined Patent Publication No. 75448/1983) is known, but this is not an economical production method considering the use of expensive triphenylphosphine and an expensive base. It's hard to say.

On the other hand, a conjugated diene such as 1-(5-methyl-2-furyl)-2,4hexadiene or 2,4-hexadienoic acid butyl ester is converted into a metal carbonyl represented by the general formula (II) below or an arene complex thereof. A method of constructing a cis double bond at the 3-position through a catalytic hydrogenation reaction in the presence of a catalyst is known (Japanese Patent Publication No. 61-2377, No. 2).
Abstracts of the 4th Kakuronkai Conference on Flavor Terpene and Essential Oil Chemistry, pp. 135-137).

Based on this knowledge, the present inventor attempted to catalytically hydrogenate 2,4-hexadienal, which can be easily produced manually, in the presence of the catalyst to obtain cis-3-hexenal simply and economically. However, side reactions occurred and the desired product could not be obtained in good yield.

(Problems to be Solved by the Invention) As a result of intensive research to solve the above-mentioned drawbacks, the present inventors have found two
．． If 4-hexadienal is converted to 2,4-hexadienal dialkyl acecule, catalytic hydrogenation can occur with high selectivity in the presence of the catalyst, resulting in cis-3
-Hexenal dialkyl acecule can be obtained in good yield, and it has been discovered that cis-3-hexenal can be obtained in good yield by further hydrolyzing this product, and based on this knowledge, the present invention has been completed. .

(Means for Solving the Problems) Thus, according to the present invention, as the first invention, the general formula (1
) (wherein R' and R2 represent a lower alkyl group or a lower alkylene group bonded to each other); arene),
(II) (wherein M4; t: represents a metal atom selected from 2iY consisting of Cr, Mo and W,
arene is an arene ligand. And X is 1 or 2, y is an integer from 3 to 6, and Z is O or 1 to 6.
(representing an integer of 3), wherein R1 and R2 are Provided is a method for producing cis-3-hexenal dialkyl acecule represented by

A second invention provides a method for producing cis-3-hexenal, which comprises hydrolyzing the cis-3-hexenal dialkyl acecul obtained by the method described above.

The 2,4 hexadienal dialkyl acecul used as a starting material in the present invention is represented by the above-mentioned -C formula (1). R1 constituting the acetal moiety
Specific examples of R2 include lower alkyl groups such as methyl, ethyl, propyl, butyl, and R1 and R2.
Examples include lower alkylene groups such as ethylene, trimethylene, and propylene groups to which 2 is bonded. 2
Specific examples of 4-hexadienal dialkyl acecool include 2,4-hexadienal dimethyl acecool, 2,4-hexadienal chetyl acecool, 2,
4-hexadienal dipropyl acecool, 2,4-
Hexagenal dibutyl acetal, 2-(L3-pentagenyl)-1,3-dioxolane, 2-(1,3
-pentagenyl)-4methyl-1,3-dioxolane, 2-(L3-pentagenyl)-1,3-dioxane, and the like.

Such 2,4-hexagenal can be easily produced by reacting 2,4-hexagenal obtained by reacting 2-butinal and acetaldehyde with a lower alcohol or orthoformic acid ester. It can be bottomed out.

In the present invention, a catalytic hydrogenation reaction of 2,4-hexadienal dialkyl acecule is carried out using a metal carbonyl represented by the above formula (II) or an arene complex thereof as a catalyst. As mentioned above, such catalysts have been conventionally used as catalysts for the catalytic hydrogenation of diene compounds, and include, for example, hexaluponylchromium, benzenetricarbonylchromium, thiophene I-licarbonylchromium, pyridinetricarbonylchromium, and anisoletricarbonylchromium. ruphonylchromium, chlorhenzentricarbonylchromium, methylhenzuate tricarbonylchromium, hydride l, 1doπ-
■Coventadienyl I/licarbonylchromium, π-
Cyclobentadienylmemethi-licarubonylchromium, cyclohebutanetrientricarbonylchromium, cyclooctatrientrycarbonylchromium,
Mesitylene tricarbonyl chromium, stilbene hexacarbonyl chromium, acetophenone tricarbonyl chromium, benzene tricarbonyl molybdenum, mesitylene tricarbonyl molybdenum, pyridine tricarbonyl molybdenum, azulene hexacarbonyl molybdenum, cyclohebutane I-licarbonyl molybdenum, cyclooctatricarbonyl molybdenum , di-π-cyclopentadienylhexacarbonyldimolybdenum, hydride
π-cyclopentadienyltricarbonylmolybdenum,
Examples include Henzen tricarbonyl tungsten, l-reentrant carbonyl tungsten, pyridine pentacarbonyl tungsten, cyclooctadiene tetracarbonyl tungsten, mesitylene tricarbonyl tungsten, and among them, chromium compounds are preferred in terms of yield.

The amount of such a catalyst to be used is usually 10 to 10-5 mol%, preferably 5 to 10-2 mol%, based on the starting compound of general formula (,l).

Although the catalytic hydrogenation reaction of the present invention can be carried out without a solvent, it is preferably carried out in the presence of any inert organic medium that can dissolve the raw material compound of general formula (1). Inert organic media include, for example, methanol, ethanol, propanol, butanol, ethylene glycol, propylene glycol, alcohols such as -\alcohol, diethyl ether, trihydrofuran,
Ethers such as dioxane, esters such as ethyl acetate, methyl acetate, pentane, hexadiene,
Aliphatic or alicyclic hydrocarbons such as heptano, cyclopenkune, cyclo-xane, methylcyclohexane, etc., and aromatic hydrocarbons such as heptane, toluene, xylene, etc. are used alone or in combination. be able to.

The reaction is carried out at room temperature to 230° C1, preferably 40 to 200°
Under heating at C, under appropriate hydrogen pressure, e.g. 2 to 150 kg
This is achieved by carrying out the reaction under a hydrogen pressure of /cm' for 10 minutes to 20 hours, preferably 2 to 5 hours.

After the reaction, highly pure cis-3-hexenal sialylacecour can be obtained by purification by means such as distillation.

Next, cis-3-hexenal can be easily obtained by hydrolyzing the thus obtained cis-3-hexenal dialkyl acecul in accordance with a conventional method. The hydrolysis reaction is carried out in the presence of an acid such as hydrochloric acid, sulfuric acid, phosphoric acid, formic acid, acetic acid, oxalic acid, monochloroacetic acid, trichloroacetic acid, acidic ion exchange resin, and the like.

During the reaction, it is preferable to coexist water or a mixed solvent of water and an inert organic solvent, and examples of the organic solvent include acetone, tetrahydrofuran, dioxane, dimethylformamide, dimethylsulfoxide, and methanol.

The reaction conditions are not particularly limited, but the reaction temperature is usually 18
The reaction time at 0 to 200°C is 20 minutes to 10 hours.

After the reaction, for example, the reaction product is extracted with a suitable solvent and distilled to obtain cis-3---- Gisenal in high yield and high degree of chaos.

(Effects of the Invention) Thus, according to the present invention, cis-3-hexenal can be obtained in high yield through a simple process from raw materials that can be easily obtained manually compared to the conventional techniques.

(Example) The present invention will be explained in more detail with reference to the following example. In addition, the percentages in the examples, comparative examples, and reference examples are based on the weight basis ff1lu unless otherwise specified.

Reference Example 1 Synthesis of 2,4-hexadienal dimethyl acecure To a mixture of 96.2 g of 2,4-hexadienal and 132.6 g of methyl orthoformate, 4 ammonium nitrate was added.
．． 0 g of methanol and 60 g of methanol) were added, and the mixture was stirred at room temperature for 6 hours. After the reaction, the precipitate was removed by filtration, anhydrous sodium carbonate 6,0g was added, and methanol, unreacted methyl ortho-formate, and methyl formate produced by the reaction were distilled off under reduced pressure. The obtained crude product was distilled under reduced pressure 3 and 2,4-hexagenal dimethyl acetal 9
9.7 g was obtained. The yield of 2,4-hexadienal dimethylacecool based on the 2,4-hexadienal used was 70 mol%.

Example 1 Synthesis of cis-3-hexenal dimethylacecool Ill! In an autoclave, 568 g of 2,4-hexadienal dimethyl acecool and 200 mI of methylcyclohexadi! and 2.2 g of hexaluponylchromium
After replacing the air inside with nitrogen, replace the hydrogen with 5
The mixture was introduced under pressure at 0 kg/cm2 and reacted at 190 to 195°C for 3 hours with stirring. After cooling, the reaction mixture was taken out, the precipitate was removed by filtration, and then distilled under reduced pressure to obtain 49.5 g of cis-3-hexenal dimethyl acecool. The yield was 86 mol% based on the 2,4-hexadienal dimethylacecool used in the reaction.

Incidentally, cis-3-hexenaldimethylacecool was identified by measuring the IR spectrum and 'It-NMR spectrum values.

■4 Example 2 50 [] rn in the autoclave 2,4-he-)-ri'genal dinotyl acecool 1.4.2
g, Tetoushi; Lofuran l 00 m p, *; and Notylhenzue 1 tricarbonyl chromium 1.3g were added,
After replacing the internal air with nitrogen for 11 minutes, 50 kg of hydrogen was added.
/cm2, and heated at 120-130°C for 31. The reaction was allowed to continue under stirring for 10 minutes. When the 6 mixture was distilled under reduced pressure, cis 3-hegicenal cimethyl acetal 1.1.4
g was obtained. Yield: 51 to 2,4- used in the reaction:
It was mol%.

Example 3 Synthesis of 2.4-Hexadienaldiethyl acecule 30.0 g of 2,4-hexadienal diethyl acecool, 100 rr12 of methylcyclohexane and 1. After 1g of hydrogen was introduced, the air inside was sufficiently replaced with nitrogen, 50kg/cm2 of hydrogen was introduced, and the temperature was 190~1.
The reaction was allowed to proceed at 195°C for 3 hours under stirring.

5 The reaction mixture was treated in the same manner as in Example 1, resulting in cis-3
- 25.88 g of hexenal diethyl acecure was added to I). The yield was 85 mol% based on the 2,4-hexagenal dimethylacecool used in the reaction.

Incidentally, cis-3-hexenal diethyl acecool was identified by measuring the IR spectrum and the 'II-NMR spectrum' value.

Practical example 4 Synthesis of cis-3-hexenal 1p equipped with stirrer, dropping row 1, thermometer and reflux condenser
, 4] In a coffin flask, add 36.0 g of cis-3-hexenal diethyl acecool, 7150 g of acetic acid, and oxalic acid dihydrate 7. After stirring, 180 g of water distilled into the mixture was added dropwise through a dropping funnel while maintaining the temperature at 50° C. in a water bath under a nitrogen atmosphere. 'After dropping,
After stirring for another 30 minutes at the same temperature, the mixture was cooled with ice water, and 6 g of hydrogen carbonate was added and stirred. Further, salt was added to saturate the mixture, and extraction was performed three times with ether. Whisk the ether layer and add 5% hydrogen carbonate to 1~lium water? Liquid 8 and 6 were then distilled under reduced pressure to obtain 147 g of cis-3-h-1-cenal. The yield in the cis-3 hexenal dimethyl acecure used in the reaction was 60 mol%.

Incidentally, cis-3-hexenal was identified by measuring the jR spectrum and the '1m-NMR spectrum.

Comparative example 2. Hydrogenation of 4-hex-s'genal 50
Into a 0 mff autoclave, put 9.6 g of 2,4-hegizagenal, 100 ml of methylcyclohagizan, and 1.1 g of hexalponylchromium, and after replacing the air inside with nitrogen by ζ size, hydrogen was added to 50 kg/c.
m 2 was introduced under pressure, and the reaction was continued at a temperature of 190 to 1.95°C for 3 hours with stirring. Analysis of the reaction mixture by gask [171 graphography] revealed that the raw material 2,4 hexadienal was completely consumed, but the [171 cis-
Little 3-hexenal was obtained, giving a complex mixture.

Claims (1)

[Claims] 1. General formula (I) ▲ Numerical formula, chemical formula, table, etc. ▼ (I) (In the formula, R^1 and R^2 represent a lower alkyl group or a lower alkylene group bonded to each other. ) represented by 2,
4-hexadienal dialkyl acetal, general formula (II) M_x(CO)_y(arene)_z(II) (in the formula,
M represents a metal atom selected from the group consisting of Cr, Mo and W, and arene represents an arene ligand. And x is 1 or 2, y is an integer from 3 to 6, and z
(represents 0 or an integer from 1 to 3) General formula (III) characterized by carrying out a catalytic hydrogenation reaction in the presence of a metal carbonyl or its arene complex catalyst ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (III) A method for producing cis-3-hexenal dialkyl acetal represented by (wherein R^1 and R^2 are the same as above). 2. General formula (I) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (I) (In the formula, R^1 and R^2 represent a lower alkyl group or a lower alkylene group bonded to each other) 2,
The 4-hexadienal dialkyl acetal is represented by the general formula (II) M_x(CO)_y(arene)_z(II) (wherein,
M represents a metal atom selected from the group consisting of Cr, Mo and W, and arene represents an arene ligand. And x is 1 or 2, y is an integer from 3 to 6, and z
(represents 0 or an integer from 1 to 3) is subjected to a catalytic hydrogenation reaction in the presence of a metal carbonyl or its arene complex catalyst to form the general formula (III) ▲There are mathematical formulas, chemical formulas, tables, etc.▼(III) ( A cis-3-hexenal dialkyl acetal represented by the formula (wherein R^1 and R^2 are the same as above) is obtained and then hydrolyzed.
-Production method of hexenal.