JPS5988443A - Production of 2-cyclopentenone ester - Google Patents

Abstract

PURPOSE:To obtain easily the titled compound useful as an agricultural chemical using the whole compound, by reacting either one of optically active 4-cyclopentenones handled as useless compounds with a lower aliphatic carboxylic acid under heating. CONSTITUTION:An optically active 4-cyclopentenone of formula I (R is OH or OOCR'; R' is H or lower alkyl; R1 is H, alkyl or alkenyl; R2 is alkyl, alkenyl or alkynyl), e.g. 3-hydroxy-2-methyl-4-cyclopentenone or 3-hydroxy-2-ethyl-4- cyclopentenone, as a raw material is reacted with a lower aliphatic carboxylic acid, e.g. formic acid or propionic acid, in an amount of one equivalent or more, preferably 2 equivalents or more at 50-160 deg.C, preferably 60-140 deg.C to give the aimed compound of formula II (R3 is H or lower alkyl).

Description

Detailed Description of the Invention The present invention is based on the general formula (n) (wherein R1 is a hydrogen atom, an alkyl group or an alkenyl group, R2 is an alkyl group, an alkenyl group or an alkynyl group, and R8 is a hydrogen atom or a lower In more detail, regarding the method for producing 2-cyclobentenone esters represented by the general formula (I) (wherein the alkyl group is represented by
R1 and R2 have the same meanings as above, and k is -OH or -0OCR1.

Here, ' is a hydrogen atom or a lower alkyl group. 4-cyclobentenones represented by ) and a lower aliphatic carboxylic acid are reacted under heating.
This is a method for producing 2-cyclobentenone esters shown below.

In addition, the 2-cyclopenteno diesters in the present invention have a slight (+) # or (-) optical rotation, and therefore, to be more precise, either d- or t is present in slight excess. Although it is a mixture of optical isomers, its optical purity is generally very low, so it may be referred to as a racemate for convenience in the following text.

The present inventors previously discovered that the optically active 4 represented by general formula (I)
- We have proposed cyclobentenones and their production methods, and have found that these compounds are extremely important as agricultural chemicals or pharmaceutical intermediates/forms depending on their optically active form, but there are certain uses. For example, when the main purpose is to use agrochemicals such as a pesticide, 4-cyclobentenones with negative optical rotation may be useful, but their symmetry, 4-cyclobentenone with positive optical rotation, may be useful. Pentenones are not effective for that purpose.

Therefore, of the 4-cyclobentenones represented by the general formula (I), only one optically active form can be effectively used, and its symmetric form is unnecessary, and the utility value of the compound as a whole is low. There's a problem.

For this reason, the present inventors have conducted studies to effectively utilize the other optically active form of the 4-cyclobentenones represented by the general formula (I), which would otherwise be unnecessary. It has been discovered that 2-cyclobentenone esters represented by general formula (II) can be obtained in the caries form by reacting 4-cyclopentenones represented by formula (I) under specific conditions, This led to the present invention.

That is, as described above, the present invention provides a racemic form of 2-cyclopentenone esters represented by the general formula (1) by rearrangement with an optically active 4-cyclobentenone represented by the general formula (I). This is the way to obtain it.

The 2-cyclobentenone esters represented by the general formula (■) obtained by the present invention can be produced by hydrolyzing the racemic 2-substituted-4-hydroxy-8
-Methyl-2-cyclobentenoni/, which can be effectively used in racemic form for insecticide applications.

Thus, according to the present invention, one of the optically active forms of the 4-cyclobentenones represented by the general formula (I), which was treated as an unnecessary compound, is converted into a reusable compound. The economic significance of the present invention is extremely high.

In the present invention, the 4-cyclopentenones used as raw materials include, for example, 3-hydro-2-methyl-4-cyclobentenone, 3-hydroxy-2-ethyl-4-cyclobentenone, 3-hydroxy- 2-n-propyl-4-cyclobentenone,
3-hydroxyl 2-iso-propyl-4-cyclobentenone, 3-hydroxy-2-n-butyl-3-4-cyclobentenone, 8-hydroxy-2-n-pentyl-
4-cyclobentenone, 3-hydroxy-2-n-hexyl-4-cyclobentenone, 3-hydroxy-2-n
-hebutyl-4-cyclobentenone, 8-hydroxy-
2-allyl-4-cyclopentenone, 3-hydroxy-
2-(2-cis-butenyl)-4-cyclobentenone,
3-hydroxy-2-(ω-butenyl)-4-cyclobentenone, 3-hydroxy-2-(2-trans-pentenyl)-4-cyclobentenone, 3-hydroxy-2
-(8-cis-hexenyl)-4-cyclobentenone,
3-hydroxy-2-propargyl-4-cyclobentenone, 3-hydroxy-2-(2-pentynyl)-4-
Cyclobentenone, 3-hydroxy-2-(α-methylallyl)-4-cyclopentenone, 8-hydroxy-2
-(1-cyclopentenyl)-4-cyclobentenone,
8-hydroxy-2-cyclohexyl-4-cyclobentenone, 8-hydroxy-2,3-dimethyl-4-cyclobentenone, 3-hydroxy-2-ethyl-3-methyl-4-cyclobentenone, 8- Hydroxy-2-11
-propyl-8-methyl-4-cyclobentenone, 8-
Hydroxy-2-isopropyl-8-methyl-4-cyclobentenone, 3-hydroxy-2-n-butyl-3-
Methyl-4-cyclobentenone, 3-hydroxy-2-
n-pentyl-3-methyl-4-cyclopentenone, 3
-Hydroxy-2-n-hexyl-8-methyl-4-cyclobentenone, 3-hydroxy-2-n-hexyl-
8-methyl-4-cyclobentenone, 3-hydroxy-
2-allyl-3-methyl-4-cyclobentenone, 3-
Hydroxy-2-(2-cis-butenyl)-8-methyl-4-cyclobentenone, 8-hydroxy-2-(ω-
(futhynyl)-8-methyl-4-cyclobentenone, 8-
Hydroxy-2-(2-cis-pentenyl)-8-methyl-4-cyclobentenone, 3-hydroxy-2-(2
-) lance-pentenyl)-3-methyl-4-cyclobentenone, 8-hydroxy-2-(3-cis-hexenyl)-8-methyl-4-cyclopentenone, 8-hydroxy-2-propargyl-3 -Methyl-4-cyclobentenone, 8-hydroxy-2-(2-pentynyl)-3
-Methyl-4-cyclobentenone, 8-hydroxy-2
-(α-methylallyl)-8-methyl-4-cyclobentenone, 3-hydroxy-2-(1-cyclopentenyl)-8-methyl-4-cyclobentenone, 8-hydroxy-2-cyclohexyl-3 -Methyl-4-cyclobentenone and compounds in which the hydroxyl group at the 8-position in these compounds is substituted with an acetoxy group or a propionyloxy group are exemplified.

Examples of lower aliphatic carboxylic acids, which are the other reaction raw materials, include formic acid, acetic acid, propionic acid, butyric acid, and valeric acid. 1. Used in combination with potassium salts, calcium salts, copper salts, zinc salts, palladium salts, lead salts, tin salts, manganese salts, etc.), organic amine salts (e.g. trimethylamine salts, triethylamine salts, pyridine salts, picoline salts, etc.) However, it is particularly preferable to use a carboxylic acid and its metal salt in combination.

The reaction between the optically active 4-cyclobenteno di/s represented by the general formula (I) and the lower aliphatic carboxylic acid is carried out by heating in the presence or absence of a solvent.

When a solvent is used in this reaction, examples of the solvent include aliphatic compounds such as tetrahydrofuran, ethyl ether, acetone, methyl ethyl ketone, toluene, benzene, chlorobenzene, dichloromethane, dichloromethane, chloroform, dichloromethane, dimethylformamide, dimethyl sulfoxide, etc. Alternatively, solvents such as aromatic hydrocarbons, ethers, halogenated hydrocarbons, etc., which are inert to the reaction, may be used alone or in mixtures.

There is no particular restriction on the amount 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 acid used is
It is required to be used in an amount of 1 equivalent or more, preferably 2 equivalents or more, based on the optically active 4-cyclobentenone.

The reaction temperature is arbitrary in the range of 50 to 160°C, but preferably in the range of 60 to 140°C.

There is no particular restriction on the reaction time. Through such a reaction, racemic cyclobentenone esters represented by general formula (II) can be easily obtained in good yields, and these can be separated by conventional separation methods such as extraction, separation, concentration, and distillation. It can be easily isolated from the reaction mixture by et al.

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

Example 1 d-2- was placed in a Yotsuro flask equipped with a stirrer and a thermometer.
Allyl-8-hydroxy-3-methyl-4-cyclobentenone s, sy [optical rotation α] D + 22.5. (C
=1. chloroform)], 20 g of acetic acid and 0.4 f of sodium acetate were added, and the mixture was stirred under reflux for 7 hours.

After the reaction, acetic acid was distilled off under reduced pressure, and toluene was added to the residue.
0- and water 1o- are added for extraction treatment.

After washing the organic layer with sodium bicarbonate and water, the toluene is distilled off. The concentrated residue was purified by column chromatography to obtain 4-amythoxy-2-allyl-3-methyl-2-cyclobentenone8.
65g (94% collected) was obtained.

b-p 100-110°C 10.1-0.8 Hg optical rotation α]D-1,8° (c=1.chloroporm) In the above example, 0.4 g of sodium acetate was replaced with The reaction and treatment were carried out in exactly the same manner except that the acetate shown in 1 was used, and the yield of the target compound was as shown in Table 1.

Table 1 Example 2 t-2-allyl-3-hydroxy-8-methyl-4-cyclobentenone instead of d-2-allyl-3-hydroxy-8-methyl-4-cyclobentenone s, syc optical rotation α〕9-2′8.9° (C=l, chloroform)
] The reaction and post-treatment were carried out in the same manner as in Example 1 except that
Further column chromatography purification (toluene:ethyl acetate-1
0:1) to give 4-acetoxy-2-allyl-3-methyl-2-cycloentenone a, 58y (yield 91%).

0 optical rotation 2 α], +2.4° (c = 1', chloroform) Example 8 In a flask similar to that used in Example 1, t-3-acetoxy-2-allyl-3-methyl-0 4-cyclo bentenone a, s y [optical rotation α] 9
-98.6° (C=l, chloroform)], 30-propionic acid, and 1.5 g of sodium propionate, and stirred at 110 to 120°C for 6 hours.

After the reaction is completed, propionic acid is distilled off under reduced pressure, and the residue is extracted with 8 kg of toluene (11 kg, 20 kg of water).

Thereafter, 8.1 g (yield: 80%) of 2-allyl-4-propionyloxy-3-methyl-2-cyclobentenone was obtained by post-treatment according to Example 2.

Optical rotation: α]D -1,1° (C=1, chloroform) Example 4 T-8-
Arotoxic 2-allyl-3-methyl-4-cyclobentenone 8.88g [optical rotation α] D-98-6° (c=
1, chloroform)], 30-acetic acid, and 1 g of sodium acetate, and stirred under reflux for 5 hours.

After the reaction, acetic acid was distilled off under reduced pressure, and toluene was added to the residue.
Add 0-t and 20-liters of water and perform an extraction process. After washing the organic layer with sodium bicarbonate water, toluene is distilled off. The concentrated residue was purified by column chromatography to obtain 4-acetoxy-2-allyl-
8.11 g of 3-methyl-2-cyclobentenone (8.1 g of 3-methyl-2-cyclobentenone
2%).

Optical rotation α], = 0.9° (c=1, chloroform) Examples 5 to 9 Reaction was carried out in the same manner as in Example 4 except that the compounds shown in Table 2 were used as optically active 4-cyclobentenones. Table 2 shows the results of the treatment.

Examples 10 to 14 Table 8 shows the reaction and treatment results in the same manner as in Example 1, except that the compounds shown in Table 8 were used as optically active 4-cyclobentenones.

Example 15 In a flask similar to that used in Example 1, propionic acid 2 (
Prepare ld and 1.5 g of sodium propionate,
Heat to 100°C. Then 1-8-acetoxy-2,3
-dimethyl-4-cyclobentenone [optical rotation α] D-1
9.6° (C=1.chloroform) 18.86N was added dropwise over 1 hour. It is further held at the same temperature for 6 hours. Thereafter, post-treatment was carried out according to Example 8, and 2.8-dimethyl-4-propionyloxy-2-cyclobentenone 8.
021 (yield 83%) was obtained.

Optical rotation α ] D −0,6° (c = 1. Chloroform) Voluntary writing of procedural amendment) June 17, 1980 Director-General of the Patent Office Kazuo Wakasugi 1, Incident Indication 1982 Patent Application No. 199588 2, Title of the invention 2 - Process for producing cyclobentenone esters 3, Relationship with the amended case Patent applicant 5-15 Kitahama, Higashi-ku, Osaka (209) Sumitomo Chemical Co., Ltd. Representative Takeshi Hijikata 4, Agent Personal contact information ([16) 220-34046, Contents of amendment (1) Regarding Nα8 and 9 in Table 2 on page 16 of the specification)
] p is r-o, 46J, "-0,7°, respectively
”, respectively, correct it to T: +4″J, r+7°”.

(2) In Nos. 13 and 14 of Table 3 on page 17, the α-po of the target 2-cyclobentenone ester (n) is r+0.4°J, r+o, and so, respectively. Correct as r+4.2°j and r+8.1' J.

that's all

Claims (1)

[Claims] General formula (wherein R represents -OH or 10OCR', where ' is a hydrogen atom or a lower alkyl group.P
-1 is a hydrogen atom, an alkyl group, or an alkenyl group,
R2 represents an alkyl group, an alkenyl group or an alkynyl group, respectively. ) is characterized by reacting an optically active 4-cyclobentenone with a lower aliphatic carboxylic acid under heating (in the formula, yen and suke have the same meanings as above, and phantom is A method for producing 2-cyclobentenone esters represented by (representing a hydrogen atom or a lower alkyl group)