JPS5939852A - Preparation of cyclopentenone ester - Google Patents

Abstract

PURPOSE:To obtain the titled compound useful as an agricultural chemical and its derivative, etc. easily in high yield and industrially advantageously, by reacting a cyclopentenone alcohol to be easily synthesized with a lower fatty carboxylic acid. CONSTITUTION:A cyclopentenone alcohol shown by the formula I (R1 is H, alkyl, or alkenyl; R2 is alkyl, alkenyl, alkynyl, cycloalkyl, etc.) is reacted with a lower fatty carboxylic acid (e.g., both carboxylic acid such as formic acid, acetic acid, propionic acid, butyric acid, etc. and its metal salt are preferably used), to give a cyclopentenone ester shown by the formula II (R is H, or lower alkyl). 2-Methyl-3-hydroxy-4-cyclopentenone, etc. may be cited as the compound shown by the formula I . The compound shown by the formula I is easily obtained by rearrangement of a furancarbinol.

Description

Detailed Description of the Invention The present invention is based on the general formula (I) (where kl is a hydrogen atom, an alkyl group, an alkenyl group, and phantom is an alkyl group, an alkenyl group, an alkynyl group, a cycloalkyl group, an aryl group, - cyanohexyl group, k represents a hydrogen atom or a lower alkyl group).

By reducing the cyclobentenone powder represented by the general formula (I) with acetic acid, a cyclobentenone derivative in which the acyloxy group is replaced with hydrogen can be obtained, and this compound is extremely important as a fragrance. be.

Such a cyclobentenone ester can be synthesized by esterification of an alcohol corresponding to Q O or substitution reaction of a halogen atom, as shown in the following formula, but in either method, the raw materials themselves are expensive; Even as an industrial manufacturing method, there are drawbacks and it is not satisfactory.

Based on this, the present inventors researched a new method for producing cyclobentenone ester represented by general formula (I), and found that the desired product was obtained in good yield by a novel reaction that was completely unknown until now. We have found an industrially advantageous method for obtaining this, and have completed the present invention.

That is, the present invention is directed to the general formula (10, in which R1 and R2 have the same meanings as above), which is characterized in that cyclobentenone alcohol and lower aliphatic carboxylic acids are allowed to react with each other.
This is a method for producing a cyclobentenone ester represented by I).

Such a reaction is a novel reaction revealed for the first time by the present inventors.

In this reaction, cyclobentenone alcohol used as a raw material can be easily synthesized by rearranging furancarbinols as shown in the following equation.

(In the formula, R1 and R2 have the same meanings as above.

) Specifically, the cyclobentenone alcohol represented by the general formula (6) is 2-methyl-8-hydroxy-
4-cyclo, bentenone, 2-ethyl-8-hydroxy-4-cyclobentenone.

2-n-propyl-8-hydroxy-4-cyclobentenone, 2-isopropyl-8-hydroxy-4-cyclobentenone, 2-n-butyl-8-hydroxy-4-cyclobentenone, 2-n- pentyl-8-hydroxy-
4-cyclobentenone, 2-n-hexyl-8-hydroxy-4-cyclobentenone, 2-n-hebutyl-8-
Hydroxy-4-cyclobentenone, 2-allyl-8-
Hydroxy-4-cyclobentenone, 2-(2-cis-
butynyl)-8-hydroxy-4-cyclobentenone,
2-(2-cis-benanyl)-3-hydroxy-4-
Cyclohentenone, 2-(2-trans-pentenyl)
-8-Hydroxy-4-cyclobentenone.

2-(B-cis-hexenyl)-3-hydroxy-4-
Cyclobentenone, 2-propargyl-8-hydroxy-4-cyclobentenone, 2-(2-pentynyl)-8
-Hydroxy-4-cyclobentenone, 2-(ω-cyanohexyl)-8-hydroxy-4-cyclobentenone, 2-phenyl-8-hydroxy-4-cyclobentenone, 2-(α-methylallyl)- 3-hydroxy-4-
Cyclobentenone, 2-methyl-8-hydroxy-3-
Methyl-4-cyclobentenone, 2-ethyl-8-hydroxy-3-methyl-4-cyclobentenone, 2-n-
Propyl-8-hydroxy-8-methyl-4-cyclobentenone, 2-n-butyl-3-hydroxy-3-methyl-4-cyclobentenone, 2-n-pentyl-8-hydroxy-8-methyl- 4-cyclobentenone, 2-n
-hexyl-8-hydroxy-8-methyl-4-cyclobentenone, 2-n-hebutyl-8-hydroxy-8-
Methyl-4-cyclobentenone, 2-allyl-8-hydroxy-3-methyl-4-cyclobentenone, 2-(2
-cis-butynyl)-3-hydroxy8-methyl-4-
Cyclobentenone.

2-(2-cis-butynyl)-3-hydroxy-8-methyl-4-cyclobentenone, 2-(2-trans-pentenyl)-8-hydroxy-4-cyclobentenone,
2-(8-cis-hexenyl)-8-hydroxy-8-
Methyl-4-cyclobentenone, 2-phenyl-8-hydroxy-8-methyl-4-cyclobentenone 2-p-
Chlorophenyl-3-hydroxy-8=methyl-4-cyclobentenone, 2-propargyl-8-hydroxy-
8-Methyl-4-cyclobentenone, 2-(2-pentynyl)-8-hydroxy-8-methyl-4-cyclobentenone, 2-n-pentyl-3-allyl-8-hydroxy-4-cyclo Guntenone, 2-(ω-cyanohexyl)-8-hydroxy-8-methyl-4-cyclobentenone, and the like are exemplified.

In addition, lower aliphatic carboxylic acids, which are the other reaction raw materials, include carboxylic acids such as formic acid, acetic acid, propionic acid, butyric acid, and valeric acid, and metal salts thereof (for example, lithium salts, sodium salts, potassium salts, calcium salts, copper salts, zinc salts, palladium salts, lead salts, tin salts, manganese salts, etc.) and organic amine salts (such as trimethylamine salts, triethylamine salts, pyridine salts, picoline salts, etc.), and these may be used alone or in mixtures. In particular, it is preferable to use a carboxylic acid and a metal salt thereof in combination.

-ff cyclobentenone arL represented by formula (II)
The reaction between t-col and lower aliphatic carboxylic acids is carried out by heating in the presence or absence of a solvent.

In this reaction, when a solvent is used, examples of the solvent include aliphatic or Examples include solvents that are inert to the reaction, such as aromatic hydrocarbons, ethers, and halogenated hydrocarbons, either alone or as a mixture. There are no particular restrictions on the needle used.

Moreover, lower aliphatic carboxylic acid, which is a reaction component, can also be used as a solvent.

In this reaction, the amount of lower aliphatic carboxylic acids to be used is at least 1 equivalent per cyclobentenone alcohol (I[), preferably at least 2 equivalents.

The reaction temperature is 0 to 150°C, preferably 30 to 1
It is in the range of 40°C.

There is no particular restriction on the reaction time.

Through such a reaction, the cyclobentenone ester represented by the general formula (I) can be easily obtained in a good yield,
These can be carried out using conventional separation means such as extraction, branching, concentration,
It can be easily isolated from the reaction mixture by distillation or the like.

The present invention will be explained below with reference to Examples.

Example 1 15.2 f of 2-allyl-8-hydroxy-8-menoanone, 45 d of acetic acid, and 2 f of sodium acetate are added to a four-sided flask equipped with a stirrer and a thermometer, and the mixture is stirred under reflux for 7 hours.

After the reaction, acetic acid was distilled off under reduced pressure, and toluene 6 was added to the residue.
Add 0 ml and 4 o of water for extraction.

After washing the organic layer with sodium bicarbonate and water, toluene is distilled off. The concentrated residue was distilled to obtain 4-acedoxy-2-allyl-3-methyl-2-cyclopentenone.

Yield 18. fM (yield 95.8%) b, p, too~ito°C 10. i〜o−a +uli
fIn addition, in the above example, the yield of the target compound was as shown in Table 1. Ta.

Table 1 Examples 2 to 9 Cyclobentenone al as described in Table 2 instead of 2-allyl-8-hydroxy-3-methyl-4-cyclobentenone in Example 1 Example IO When used in Example 1 In a similar flask, 2-aryrua-
Hydroxy-8-methyl-4-cyclobentetune15.
2N, propionic acid 60- and sodium propionate 8fI were charged, and the mixture was stirred at 120 to 180°C for 8 hours.

After the reaction is completed, propionic acid is distilled off under reduced pressure, and 60 mm of toluene and 40 mm of water are added to the residue for extraction treatment. Thereafter, the same treatment as in Example 1 was carried out to obtain 2-allyl-4-propionyloxy-8-methyl-2-cyclobentenone.

Yield 19.7N (yield 94.7%) b, p, 115-120°C 10.1-0.2 Simple 11 (1 Example 11-13 2-allyl-8-hydroxy-3- in Example 10
Table 8 shows the reaction and treatment results in the same manner as in Example 1 except that cyclobentenone alcohol listed in Table 8 was used in place of methyl-4-cyclobentenone.

Example 14 In a flask similar to that used in Example 1, 8-hydroxy-2-n-pentyl-8-methyl-4-cyclobentenone 1B, 211d! Charge 0:h acid 55- and heat and stir for 15 hours.

After the reaction, acetic acid was distilled off under reduced pressure, and toluene was added to the residue.
0- and water 50- are added for extraction treatment.

The following post-treatment was carried out according to Example 1, and 2-n-pentyl-8
-Methyl 4-acetoxy-2-cyclobentetun 20.
6N (yield 92%) was obtained. b, p, 125-18
5℃10.2~0.5Hp Procedural amendment (voluntary) June 17, 1980 Commissioner of the Japan Patent Office Kazuo Wakasugi Tonosho f1157 Patent Application No. 148609 2 Title of invention Process for producing cyclobentenone ester 3. Relationship with the case of the person making the amendment Patent applicant 5-15 Kitahama, Higashi-ku, Osaka (209) Representative Takeshi Hijikata 4, Sumitomo Chemical Co., Ltd. Contact information for the agent: (06) 220-34045; Column 6 of Detailed Description of the Invention of the Subject Specification, Contents of Amendment (1) In the second line from the bottom of page 13 of the specification, ``Example I'' is amended to read Example 10J.

that's all

Claims (1)

[Claims] The general formulas are a rukynyl group, a cycloalkyl group, an aryl group, and an ω-cyanohexyl group, respectively. A general formula characterized by reacting a cyclobentenone alcohol represented by ) A method for producing a cyclobentenone ester.