JP3010660B2 - Coumarin production method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an improvement in a method for producing coumarins from 3- (2-cyclohexanoyl) propionic esters.

Coumarins are important compounds especially in the perfumery industry. It is also an important compound as an intermediate for pesticides, medicines and dyes.

(Prior Art) Coumarins can be produced by subjecting 3- (2-cyclohexanoyl) propionic acid esters to a cyclodehydrogenation reaction by heating in the presence of a noble metal catalyst such as palladium (US (Patent No. 3,442,910), and a method of producing by co-existing barium sulfate, chromium oxide and the like as a co-catalyst together with a noble metal catalyst such as palladium and cyclodehydrogenation (JP-A-60-188102). .

(Problems to be Solved by the Invention) However, the yield of coumarones is not always high in the conventional method.

The present inventors have conducted intensive studies on a method for producing coumarin and a derivative thereof with good yield and economy, and as a result, have found a novel cocatalyst and completed the present invention.

(Means for Solving the Problems) That is, the present invention provides a compound represented by the general formula (I): (Wherein, R _{1 to} R ₄ each represent a hydrogen atom, a methyl group or an ethyl group, and at least two of R _{1 to} R ₄ are hydrogen atoms. R ₅ is an alkyl group having 1 to 4 carbon atoms. Is shown.)
A 3- (2-cyclohexanoyl) propionic acid ester represented by the general formula (II) by a cyclodehydrogenation reaction in the presence of a palladium catalyst; (Wherein R _{1 to} R ₄ are the same as those described above), which is carried out in the coexistence of magnesium trisilicate and / or zirconia as a co-catalyst. Production method.

3- (2-cyclohexanoyl) used in the present invention
As propionates, for example, 3- (2-
Methyl cyclohexanoyl) propionate, 3- (2-
Cyclohexanoyl) butyl propionate, 3- (2-
Methyl cyclohexanoyl-3-methyl) propionate, methyl 3- (2-cyclohexanoyl-5-methyl) propionate, 3- (2-cyclohexanoyl-4-methyl) propionate
Ethyl) propyl propionate, propyl 3- (2-cyclohexanoyl-3,4-diethyl) propionate, 3
Propyl- (2-cyclohexanoyl-3,4-dimethyl) propionate, 3- (2-cyclohexanoyl-3,5
Methyl-diethyl) propionate, methyl 3- (2-cyclohexanoyl-3-ethyl-6-methyl) propionate, and the like.

The catalyst used in the present invention includes Group IIA and III of the periodic table.
It is a solid metal catalyst in which palladium is supported on at least one carrier selected from the group consisting of Group A or Group IVA compounds, for example, carbon, alumina, silica gel, barium sulfate and the like.

These catalysts can be obtained by a known method, for example, a method of impregnating a support with a metal by an impregnation-supporting method ("Catalyst Experiment Manual" edited by the Catalysis Society of Japan, published by Maki Shoten) and reducing the hydrogen at a high temperature. May be used as it is.

If the amount of the catalyst used is small, the reaction activity is remarkably low. On the contrary, if the amount is large, the reaction activity is too high, so that many by-products are generated and the cost is high.
It is used usually in an amount of about 0.1-5% by weight, preferably about 0.5-2.5% by weight, based on propionates.

In this reaction, magnesium trisilicate and / or zirconia are added as a promoter together with a palladium catalyst. The co-catalyst is used in an amount of about 0.01 to 3% by weight, preferably about 3 to 3- (2-cyclohexanoyl) propionic acid esters.
0.05 to 0.5% by weight is used.

The cyclodehydrogenation of 3- (2-cyclohexanoyl) propionic esters is carried out at about 100 to 350 ° C., preferably at about 23 ° C.
Performed at 0-280 ° C. If the temperature is low, the reaction activity is low, and if the temperature is high, decomposition of the raw material occurs, which is not preferable.

The reaction can also be performed using a solvent. As the solvent, phenyl ether, benzyl ether, methyl-α
-Naphthyl ether, ethyl naphthalene, dimethyl biphenyl, dodecane, tetradecane, tetralin, acetophenone, phenylpropyl ketone, methyl benzoate,
And dimethyl glutamate.

The reaction is carried out by heating at a predetermined temperature for several hours to several tens of hours.

As a result of the reaction, coumarins are obtained in a yield of about 20 to 35%, and 3,4-dihydrocoumarins are obtained in a yield of about 35 to 45%. In addition, ortho-ethylphenol, methyl dihydrocinnamate, etc. are by-produced.

The 3,4-dihydrocoumarins are further dehydrogenated to be converted into coumarins, or used as a perfume raw material or the like.

(Effect of the Invention) By coexisting magnesium trisilicate and / or zirconia as the cocatalyst of the present invention, the coumarin yield can be increased.

(Examples) Hereinafter, the present invention will be described specifically with reference to Examples.
The present invention is not limited to these examples.

Example 1 Methyl 3- (2-cyclohexanoyl) propionate
200 g and 3 g of a catalyst having 5 wt% of palladium supported on activated carbon,
As a cocatalyst, 0.2 g of magnesium trisilicate was mixed in a four-necked flask, and under a nitrogen atmosphere, the number of stirring was 300 rpm, and the temperature was 240 ° C.
For 1 hour. Thereafter, the temperature was raised to 260 ° C. and heating was performed for 5 hours. The temperature was further raised to 270 ° C. and heating was performed for 15 hours.

After completion of the reaction, the reaction mixture was filtered by a catalyst and the like, and analyzed by gas chromatography. As a result, the conversion of methyl 3- (2-cyclohexanoyl) propionate was 99.8%, and coumarin and 3,4- The yield of dihydrocoumarin is 3
They were 28.7% and 36.6%, respectively, of methyl-(2-cyclohexanoyl) propionate.

Example 2 Methyl 3- (2-cyclohexanoyl) propionate
Example 1 was repeated except that 300 g was used and 0.3 g of zirconia was used instead of 0.2 g of magnesium trisilicate as a promoter.

As a result, the conversion of methyl 3- (2-cyclohexanoyl) propionate was 99.7%, and the yields of coumarin and 3,4-dihydrocoumarin were respectively based on methyl 3- (2-cyclohexanoyl) propionate. 28.0% and 40.6
%Met.

Comparative Example 1 The same procedure was performed as in Example 2 except that 0.3 g of zirconia was not used.

As a result, the conversion of methyl 3- (2-cyclohexanoyl) propionate was 99.7%, and the yields of coumarin and 3,4-dihydrocoumarin were respectively based on methyl 3- (2-cyclohexanoyl) propionate. 19.2% and 47.2
%Met.

Comparative example 2 It carried out like Example 2 except having used 0.3 g of barium sulfate as a cocatalyst.

As a result, the conversion of methyl 3- (2-cyclohexanoyl) propionate was 99.6%, and the yields of coumarin and 3,4-dihydrocoumarin were respectively relative to methyl 3- (2-cyclohexanoyl) propionate. 27.0% and 36.3
%Met.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-60-188102 (JP, A) JP-A-3-112977 (JP, A) JP-A-3-112978 (JP, A) JP-A-3-3 197478 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C07D 311/00-311/96 B01J 21/00-21/20 B01J 23/00-23/96 CA (STN)

Claims (1)

(57) [Claims] (1) a compound represented by the general formula (I): (Wherein, R _{1 to} R ₄ each represent a hydrogen atom, a methyl group or an ethyl group, and at least two of R _{1 to} R ₄ are hydrogen atoms. R ₅ is an alkyl group having 1 to 4 carbon atoms. Is shown.)
A 3- (2-cyclohexanoyl) propionic acid ester represented by the general formula (II) by a cyclodehydrogenation reaction in the presence of a palladium catalyst; (Wherein R _{1 to} R ₄ are the same as the groups described above), characterized in that coumarin is carried out in the presence of magnesium trisilicate and / or zirconia as a co-catalyst. Manufacturing methods.