JPH10130192A - Production of 2-cycloalken-1-one compounds - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject compound useful as an organic synthetic intermediate in a high yield and in a high selectivity without causing side reactions such as an intermolecular aldol condensation reaction by reacting a dicarbonyl compound in the presence of a basic catalyst in a two layer reaction medium comprising water and an aromatic hydrocarbon. SOLUTION: A water-soluble dicarbonyl compound having two or three carbon atoms between the carbonyl groups, such as a compound of formula I or II (R<1> , R<3> , R<4> , R<5> , R<6> , R<7> and R<8> are each H, an alkyl group, an alkoxy group, phenoxy group, an aryl group, hydroxyl group; R<2> is H, an alkyl group, an aryl group), as a raw material, is reacted in the presence of 0.05-0.5mole of a water-soluble basic catalyst such as sodium hydroxide in a solvent mixture comprising 1-10 pts.wt. (per pt.wt. of the raw material) of an aromatic hydrocarbon solvent such as benzene insoluble or slightly soluble in water and capable of dissolving the objective 2-cycloalken-1-one compound and 0.5-10 pts.wt. of water capable of dissolving the basic catalyst at 50-150 deg.C for 0.5-24hrs, followed by distilling, extracting, recrystallizing, etc., the reaction product to obtain the 2-cycloalken-1-one compound, such as a compound of formula III or IV.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a 2-cycloalkene-1- by cyclocondensation of a dicarbonyl compound.
The present invention relates to a method for producing onions.

[0002]

2. Description of the Related Art 2-Cycloalkene-1-ones are useful as intermediates for synthesizing various organic compounds.
As a method for producing 2-cycloalkene-1-ones from a dicarbonyl compound, a method is known in which an alcoholic solvent is reacted in the presence of a base catalyst such as sodium hydroxide, potassium carbonate, or a metal alkoxide.

However, in the above-mentioned conventional method, side reactions such as intermolecular aldol condensation and aldol condensation of generated 2-cycloalkene-1-ones occur simultaneously with the desired intramolecular aldol condensation, and the desired intramolecular aldol condensation occurs. The yield of 2-cycloalkene-1-ones decreases. Generally, in order to avoid such a side reaction, a large amount of a solvent such as water or alcohol is used, and the reaction is performed with a low concentration of the starting material. However, this method has a problem that productivity is extremely low because the starting material concentration is low.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in order to solve the problems in the above-mentioned conventional method for producing 2-cycloalken-1-ones. An object of the present invention is to propose a method for producing 2-cycloalkene-1-ones which can suppress the reaction and produce the desired 2-cycloalkene-1-ones in high yield and high selectivity. .

[0005]

The present invention relates to the following method for producing 2-cycloalkene-1-ones. (1) The number of carbon atoms between carbonyl groups is 2
Alternatively, in a method for producing 2-cycloalkene-1-ones by subjecting a dicarbonyl compound of 3 to cyclocondensation in the presence of a base catalyst, water and an aromatic hydrocarbon are used as a reaction medium to prepare these dicarbonyl compounds. A method for producing 2-cycloalkene-1-ones, wherein the reaction is carried out in a reaction medium of a layer. (2) The production method according to the above (1), wherein the dicarbonyl compound is a 1,4-dicarbonyl compound. (3) The method according to the above (1), wherein the dicarbonyl compound is 2,5-hexanedione or a derivative thereof.

The 2-cycloalkene-1-ones produced in the present invention are typically compounds represented by the following general formula [1] or [2].

[0007]

Embedded image (In the formulas [1] and [2], R ¹ , R ³ , R ⁴ , R ⁵ ,
R ⁶ , R ⁷ and R ⁸ are hydrogen, an alkyl group, an alkoxy group, a phenoxy group, an aryl group or a hydroxy group, which may be the same or different, and R ² is a hydrogen, an alkyl group or an aryl group. )

The dicarbonyl compound used as a starting material in the present invention is a dicarbonyl compound having 2 or 3 carbon atoms between carbonyl groups, and a water-soluble dicarbonyl compound can be used. As such a dicarbonyl compound, a compound represented by the following general formula [3] or [4] is representative.

[0009]

Embedded image (In the formulas [3] and [4], R ¹ , R ³ , R ⁴ , R ⁵ ,
R ⁶ , R ⁷ and R ⁸ are hydrogen, an alkyl group, an alkoxy group, a phenoxy group, an aryl group or a hydroxy group, which may be the same or different, and R ² is a hydrogen, an alkyl group or an aryl group. )

Examples of the above dicarbonyl compounds include:
2,5-dione compound, 3,6-dione compound, 1,4
The number of carbon atoms between carbonyl groups such as dicarbonyl compound is 2
Digarbonyl compound; 2,6-dione compound, 1,5
3 carbon atoms between carbonyl groups such as dicarbonyl compounds
And the like.

Specific examples of the 2,5-dione compound include 2,5-hexanedione, 3-methyl-2,
5-hexanedione, 3-phenyl-2,5-hexanedione, 1-phenyl-2,5-hexanedione, 3-
Methoxy-2,5-hexanedione, 3-phenoxy-
2,5-hexanedione, 3-hydroxy-2,5-hexanedione, 1-methoxy-2,5-hexanedione, 1-phenoxy-2,5-hexanedione, 1-hydroxy-2,5-hexanedione 2,5-hexanedione or a derivative thereof; 2,5-heptanedione.

Specific examples of the 1,4-dicarbonyl compound include 4-oxopentanal, 4-oxo-2-methylpentanal, 4-oxo-2-phenylpentanal, and 4-oxo-5. -Phenylpentanal, 4-oxo-3-phenylpentanal, 4-oxo-3-methylpentanal, 4-oxohexanal, 4-oxodecanal and the like.

Specific examples of the 2,6-dione compound include 2,6-heptanedione, 3-methyl-2,
6-heptanedione, 3-phenyl-2,6-heptanedione, 1-phenyl-2,6-heptanedione, 3-
Methoxy-2,6-heptanedione, 3-phenoxy-
2,6-heptanedione, 3-hydroxy-2,6-heptanedione, 1-methoxy-2,6-heptanedione, 1-phenoxy-2,6-heptanedione, 1-hydroxy-2,6-heptanedione 2,6-heptanedione or a derivative thereof; 2,6-octanedione;
2,6-decandione and the like.

Specific examples of the 1,5-dicarbonyl compound include 5-oxohexanal, 5-oxo-2-methylhexanal, 5-oxo-2-phenylhexanal, and 5-oxo-6-phenylhexanal. , 5-oxo-3-phenylhexanal, 5-oxo-3-methylhexanal, 5-oxodecanal and the like.

Other specific examples of the dicarbonyl compound which can be used as a starting material include 3,6
-Octanedione, 1,2-diacetylcyclohexane, 1- (2-acetylcyclohexyl) acetone and the like.

The base catalyst used in the present invention is a water-soluble base, for example, a metal hydroxide such as sodium hydroxide, lithium hydroxide or potassium hydroxide; a metal carbonate such as sodium carbonate, potassium carbonate or lithium carbonate; Carboxylates such as sodium formate and sodium acetate; and phosphates such as sodium phosphate and potassium phosphate. The amount of the base catalyst used varies depending on the type of the catalyst, but it is 0.01 to the starting material dicarbonyl compound.
１1 mol%, preferably 0.05-0.5 mol%.

The aromatic hydrocarbon used as a reaction medium in the present invention is insoluble or hardly soluble in water, and when mixed with water, separates from an aqueous layer to form an aromatic hydrocarbon layer,
Moreover, it is an aromatic hydrocarbon capable of dissolving 2-cycloalkene-1-ones.

Specific examples of such aromatic hydrocarbons include benzene, toluene, xylene, cumene, ethylbenzene and the like. The amount of the aromatic hydrocarbon to be used is 1 to 20 parts by weight, preferably 1 to 10 parts by weight, per 1 part by weight of the starting material dicarbonyl compound.

The amount of water used as a reaction medium in the present invention may be at least an amount capable of dissolving the base catalyst, and is 0.5 to 20 parts by weight based on 1 part by weight of the starting dicarbonyl compound. Parts by weight, preferably 0.5 to
It is desirable to use 10 parts by weight.

In the production method of the present invention, the starting material dicarbonyl compound is reacted in the presence of the base catalyst using water and the aromatic hydrocarbon as a reaction medium,
Cyclocondensate. In this case, the reaction is performed in a two-layer reaction medium of an aqueous layer and an aromatic hydrocarbon layer.

The reaction temperature is 20 to 250 ° C., preferably 5
It is desirable to be 0-150 degreeC. At such a reaction temperature, a side reaction is suppressed and 2-cycloalkene-1
-Ones can be produced at a high reaction rate. The reaction time depends on the dicarbonyl compound used, the catalyst or the reaction temperature, but is usually about 0.5 to 24 hours. The reaction pressure is not particularly limited as long as the reaction system can be maintained in a liquid phase, and there is no particular limitation on normal pressure or pressurization. The reaction is preferably performed with stirring.

The reaction may be carried out continuously in the liquid phase,
It may be performed batchwise and is not particularly limited. After the completion of the reaction, the 2-cycloalkene-1-ones can be separated by performing ordinary operations such as distillation, extraction, and recrystallization.

The 2-cycloalkene-1-ones thus produced are compounds in which the dicarbonyl compound as a starting material is cyclized through aldol condensation in the molecule. For example, when 2,5-hexanedione is used as the dicarbonyl compound, 3-methyl-2-cyclopentenone is obtained. This reaction is represented by the following reaction formula [5].

[0024]

Embedded image

Examples of 2-cycloalkene-1-ones other than 3-methyl-2-cyclopentenone include 3,4-dimethyl-2-cyclopentenone and 3,5-dimethyl-2.
-Cyclopentenone, 3-methyl-4-phenyl-2-
Cyclopentenone, 3-methyl-5-phenyl-2-cyclopentenone, 2-phenyl-3-methyl-2-cyclopentenone, 3-benzyl-2-cyclopentenone,
3-methyl-4-methoxy-2-cyclopentenone, 3
-Methyl-5-methoxy-2-cyclopentenone, 3-
Methyl-4-phenoxy-2-cyclopentenone, 3-
Methyl-5-phenoxy-2-cyclopentenone, 3-
Methyl-4-hydroxy-2-cyclopentenone, 3-
Methyl-5-hydroxy-2-cyclopentenone, 2-
Methoxy-3-methyl-2-cyclopentenone, 3-methoxymethyl-2-cyclopentenone, 2-phenoxy-3-methyl-2-cyclopentenone, 3-phenoxymethyl-2-cyclopentenone, 2- Hydroxy-3-
Methyl-2-cyclopentenone, 3-hydroxymethyl-2-cyclopentenone,

2-cyclopentenone, 4-methyl-2-
Cyclopentenone, 4-phenyl-2-pentenone, 2
-Phenyl-2-cyclopentenone, 5-phenyl-2
-Pentenone, 5-methyl-2-cyclopentenone, 2
-Methyl-2-cyclopentenone, 2-pentyl-2-
2-cyclopentenone derivatives such as cyclopentenone;

3-methyl-2-cyclohexenone, 3,
4-dimethyl-2-cyclohexenone, 3,6-dimethyl-2-cyclohexenone, 3-methyl-4-phenyl-2-cyclohexenone, 3-methyl-6-phenyl-
2-cyclohexenone, 2-phenyl-3-methyl-2
-Cyclohexenone, 3-benzyl-2-cyclohexenone, 3-methyl-4-methoxy-2-cyclohexenone, 3-methyl-6-methoxy-2-cyclohexenone, 3-methyl-4-phenoxy-2-cyclohexene Senone, 3-methyl-6-phenoxy-2-cyclohexenone, 3-methyl-4-hydroxy-2-cyclohexenone, 3-methyl-6-hydroxy-2-cyclohexenone, 2-methoxy-3-methyl-2 -Cyclohexenone, 3-methoxymethyl-2-cyclohexenone, 2-
Phenoxy-3-methyl-2-cyclohexenone, 3-
Phenoxymethyl-2-cyclohexenone, 2-hydroxy-3-methyl-2-cyclohexenone, 3-hydroxymethyl-2-cyclohexenone, 3-ethyl-2-
Cyclohexenone, 2,3-dimethyl-2-cyclohexenone, 3-n-butyl-2-cyclohexenone, 2-
Propyl-3-methyl-2-cyclohexenone,

2-cyclohexenone, 4-methyl-2-
Cyclohexenone, 4-phenyl-2-cyclohexenone, 2-phenyl-2-cyclohexenone, 5-phenyl-2-cyclohexenone, 5-methyl-2-cyclohexecin, 2-n-butyl-2-cyclohexenone And the like.

In the production method of the present invention, since the reaction is carried out in a two-layer reaction medium, the dicarbonyl compound as a starting material is cyclocondensed in the aqueous layer to form 2-cycloalkene-1-.
The reaction to generate the ONs proceeds, and the generated 2-cycloalkene-1-ones dissolve in the aromatic hydrocarbon and move from the aqueous layer to the aromatic hydrocarbon layer. Therefore, it is considered that side reactions are suppressed even at a high starting material concentration, and the desired 2-cycloalkene-1-ones are produced with high yield and high selectivity.

The thus obtained 2-cycloalkene-1-ones can be used as intermediates for synthesizing various organic compounds. For example, 3-methyl-2-cyclopentenone obtained by the above reaction formula (1) can be used as a synthetic intermediate of a cyclopentadienyl complex.

[0031]

According to the process for producing 2-cycloalkene-1-ones of the present invention, a dicarbonyl compound having 2 or 3 carbon atoms between a carbonyl group and a carbonyl group is converted to a water compound in the presence of a base catalyst. And aromatic hydrocarbons are reacted in a two-layer reaction medium, so that 2-cycloalkene-1-ones useful as synthetic intermediates of various organic compounds are produced in high yield and high selectivity. Can be highly productive.

[0032]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples. Example 1 1.71 g of 2,5-hexanedione in a 50 ml eggplant-shaped flask and 8.32% of a 1% by weight aqueous potassium hydroxide solution
g and 8.35 g of toluene were added, and the mixture was stirred under reflux for 3 hours. After stopping the stirring, the aqueous layer was discarded, and the amount of 3-methyl-2-cyclopentenone in the toluene layer was quantitatively analyzed by gas chromatography. As a result, the yield of 3-methyl-2-cyclopentenone was 73%.

Comparative Example 1 The procedure was as in Example 1, except that toluene was not used. As a result, the yield of 3-methyl-2-cyclopentenone was 49%.

Comparative Example 2 Example 1 was repeated except that hexane was used instead of toluene.
The same was done. As a result, the yield of 3-methyl-2-cyclopentenone was 26%.

Comparative Example 3 The procedure of Example 1 was repeated, except that 1,2-dichloroethane was used instead of toluene. As a result, the yield of 3-methyl-2-cyclopentenone was 26%.

Claims (3)

[Claims] 1. A cyclocarbonyl condensation of a dicarbonyl compound having 2 or 3 carbon atoms between carbonyl groups in the presence of a base catalyst to give 2-cycloalkene-
A method for producing 1-ones, wherein water and an aromatic hydrocarbon are used as a reaction medium, and the reaction is carried out in a two-layer reaction medium, wherein 2-cycloalkene-1-ones are produced. Method. 2. The method according to claim 1, wherein the dicarbonyl compound is a 1,4-dicarbonyl compound. 3. The method according to claim 1, wherein the dicarbonyl compound is 2,5-hexanedione or a derivative thereof.