DE1221631B - Process for the preparation of pure dextro-trans-pyrethric acid - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

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EDITORIAL

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C 07c

German KL 12 ο-25

1221631
S88872IVb / 12o
December 23, 1963
July 28, 1966

The invention relates to a new process for the preparation of dextro-trans-pyrethric acid from their mixtures with / S- (2,2-dimethyl-3-methoxycarbonyl-cyclopropyl) -methacrylic acid, which by partial saponification of the dextro-trans-chrysanthemum dicarboxylic acid dimethyl ester were obtained.

It is known that the insecticidal ingredients of the flowers of Chrysanthemum species contain pyrethrin I (general formula III, a), cinerin I (general formula III, b), pyrethrin II (general formula ίο mel III, c) and Cinerin II (general formula III, d). These compounds are esters of cyclopentenolone of the general formula I given below, namely of pyrethrolone (general formula I, a) and cinerolons (general formula I, b), with chrysanthemum monocarboxylic acid (general formula II, a) and pyrethric acid (general formula II, b), also called chrysanthemum dicarboxylic acid monomethyl ester referred to as.

CH ₃

Process for the production of pure
dextro-trans pyrethric acid

Applicant:

Sumitomo Chemical Company, Ltd.,

Osaka (Japan)

Represent

DipL-Chem. Dr. rer. nat. V. Vossius,

Patent attorney, Munich 23, Siegesstr. 26th

Named as inventor:

Masanao Matsui, Tokyo;

Hiroshi Meguro, Sendai-shi (Japan)

HIGH - HIGH CR
CH ₂ CO

(a) R = - CH ₂ CH = CH - CH = CH ₂

(b) R = - CH ₂ CH = CH - CH ₃

(I)

'CH ₃

H ₃ C _n

H ₃ C '

(a) X = -CH ₃

(b) X = - COOCH ₃

(c) X = - COOH

, CH-CH = C (

- COOH

20th 30th (d) Claimed priority: 2 Japan December 25, 1962 (58 844) = - CH ₂ CH = CH - CH = CH ₂ = —CH ₃ ²⁵ (a) R = = - CH ₂ CH = CH - CH ₃ X = = —CH ₃ (b) R = = - CH ₂ CH = CH - CH = CH ₂ X = = - COOCH ₃ (C) R = = - CH ₂ CH = CH - CH ₃ X = = - COOCH ₃ R = X =

CH ₃

O-CH C-R

I I I

CO CH ₂ -CO

H ₃ C

: h - Ch = c <

/ CH ₃

("'Recently, various analogs of the

Pyrethrum ingredients synthesized and technically produced, e.g. B. those compounds in which the radical R on the cyclopentenolone ring is an allyl, furfuryl, cyclopentadienyl or another group means.

Pyrethrin-I-type compounds are more effective in killing insects than they are Compounds of the pyrethrin-II type of the pyrethrin ingredients and their analogues. In contrast, the compounds of the pyrethrin-II type with regard to the Knook-down effect in insects is superior to compounds of the pyrethrin-I type. Accordingly there is a need for methods of making

(ΙΠ) pyrethric acid for the production of insecticides,

of this type with a superior knock-down effect.

According to Staudinger and Ruzicka, HeIv. Chim. Acta, Vol. 7, 1924, pp. 177 to 458, the compound called "pyrethric acid" is used with the

609 607/409

optical rotation value [α] Ό ⁸ = + 103.9 ° obtained by decomposition of natural pyrethrin. C1 ο mbie et al., J. Chem. Soc. (London), 1957, p. 2743, have reported that they produce "pyrethric acid" with the optical rotation value [a] ' _D ^B = + 103.4 ° by partial saponification of the dimethyl ester of an optically active chrysanthemum dicarboxylic acid (general formula II, c) have received.

M. M a t s u i and H. M e g u r ο have pyrethric acid in the pure state, starting from Chrysanthemum monocarboxylic acid, and they recognized when comparing these synthetic ones: Pyrethric acid with the so-called "pyrethric acid", which both Staudinger and Ruζicka as well as from C1 ο m b i e and employees became that this "pyrethric acid" is not pure, but a mixture of pyrethric acid with an isomeric jS- (2,2-dimethyl-3-methoxycarbonylcyclopropyl) methacrylic acid (IV), which has the following formula:

H ₃ C _x , CH - CH = C (

H ₃ C ^{x N} CH -COOCH ₃

CH ₃

COOH (IV)

The optically active pyrethric acid obtained from Mat sui and M egur o (general formula II, b) has the optical rotation value [a] l ⁵ = + 88.7 °. The optically active isomeric acid of the formula IV has the optical rotation value [α] ¥ = + 105.8 °. A mixture of equal parts of the two acids obtained from M atsui and M egur ο (general formula II, b and formula IV) practically agrees with the so-called "pyrethric acid" obtained from Staudinger and Ruζicka and from C 1 ο mbie et al from comparing their ultrared absorption spectra. Pure pyrethric acid (chrysanthemum dicarboxylic acid monomethyl ester) was first produced by M atsui and M egur ο.

Since dextro-trans-pyrethric acid is the most effective compound among the stereoisomers and optical Isomers of the acid residue of the pyrethrum ingredients and their analogues, it is advantageous to use pure dextro-trans-pyrethric acid from that obtained by partial saponification of dextro-trans-chrysanthemum dicarboxylic acid dimethyl ester so-called "pyrethric acid" obtained, which contains the isomeric acid of the formula IV, since this occurs during the esterification with the cyclopentenolone of the general formula I results in an ineffective and worthless product.

The method according to the invention is characterized in that that one can do this by partial saponification of the dextro-trans-chrysanthemum dicarboxylic acid dimethyl ester with an approximately equimolecular amount of an alkali hydroxide or low molecular weight Alcoholate obtained in water or a low molecular weight alcohol mixture of dextro-trans-pyrethric acid and dextro-trans- / S- (2,2-dimethyl-3-methoxycarbonylcyclopropyl) methacrylic acid converted into a mixture of the quinine salts with approximately the same molecular weight of quinine in acetone, the crystalline Quinine salt of dextro-trans-) S- (2,2-dimethyl-3-methoxycarbonylcyclopropyl) methacrylic acid of the formula IV separates from the filtrate the quinine salt of dextro-trans-pyrethric acid after evaporation of the acetone wins and this, if necessary after recrystallization, with a dilute acid converted into the free pure dextro-trans-pyrethric acid.

The starting mixture can be obtained by partial saponification of the dextro-trans-chrysanthemum dicarboxylic acid dimethyl ester be carried out according to conventional methods, such as those described in e.g. B. in J. Chem. Soc. (London), 1957, pp. 2743-2754. Usually the dimethyl ester with about equimolecular amount of an alkali hydroxide or a low molecular weight alcoholate in water, a brought low molecular weight alcohol or its mixture to the reaction. For example, sodium or potassium hydroxide or methylate or ethylate in hydrous methanol or ethanol used. In general, the mixture is left at room temperature or below 60 ° C for about Stand for 12 hours to several days. The low molecular weight one optionally used as a solvent Alcohol is removed by distillation, after which the reaction mixture is optionally mixed with water. After acidification, the aqueous reaction mixture yields the mixture of dextrotrans-pyrethric acid and the isomeric acid of formula IV.

For the production of the starting material, protection is not given within the scope of the present invention claimed.

For the separation of the dextrotrans-pyrethric acid according to the invention, the procedure described above is used Mixture with the equimolecular amount of quinine reacted in acetone, whereby the quinine salts form.

The quinine salts of dextro-trans-pyrethric acid (general formula II, b) and the isomeric acid of formula IV have significantly different solubility properties in acetone. For example the quinine salt of dextro-trans-pyrethric acid is soluble in acetone, that of the isomeric acid is difficult soluble. The two acids can therefore be obtained by fractional crystallization of the quinine salts in acetone separate from each other. After the separation, the quinine salt of dextro-trans-pyrethric acid becomes optionally Purified by recrystallization and then with dilute acid, e.g. B. a dilute inorganic Acid, treated, whereby the free pyrethric acid is obtained in pure form. The isomers Acid of the formula IV can be obtained in pure form in the same way. Of course you can the isomeric acid of the formula IV again into the dimethyl chrysanthemum dicarboxylate transfer, partially hydrolyze this again and the mixture obtained in this way according to the invention into the transfer pure dextro-trans-pyrethric acid.

The following example explains the process according to the invention.

The starting material can be produced as follows:

A solution of 12.6 g of dimethyl dextro-trans chrysanthemum dicarboxylate in 50 ml of methanol, 55 ml of an 1 molar methanol solution of sodium methylate and 5 nil of water are added. The mixture is left to stand for 48 hours at room temperature. The methanol is then distilled off and 50 ml of water are added to the residue. The mixture is extracted with diethyl ether to Separate neutral substances. The aqueous solution is

Carefully acidified with dilute hydrochloric acid while cooling with ice. The separating oil is with Diethyl ether extracted. The diethyl ether solution is washed with water and dried over sodium sulfate. After the ether has evaporated, the residue is distilled in vacuo. You get 10 g of a mixture of dextro-trans-pyrethric acid and the acid of the formula IV, the so-called "Pyrethric acid", from bp 140 to 150 ° C / 0.1 Torr.

example

10 g of the mixture of isomers described above are dissolved in acetone and the solution is with 16.3 g of quinine, dissolved in hot acetone, mixed. The mixture is on a water bath warmed for a few minutes and then left to stand overnight. The separating crystals (Crystals A) are filtered off and washed with acetone. The acetone filtrate and the washing solutions are combined (mother liquor B).

The crystals A are recrystallized from methanol. 8.3 g of colorless needles with a ^{melting point of 198 to 200 °} C. are obtained. After another recrystallization, the melting point rises to 204 to 207 ^° C. 8.3 g of water and then dilute hydrochloric acid are added to the quinine salt and the mixture is extracted with ether. The ether extract is washed thoroughly with water, dried over sodium sulfate and then distilled. Dextro-trans- _J 8- (2,2-dimethyl-3-methoxycarbonylcyclopropyl) methacrylic acid (IV) with a boiling point of 128 ° to 134 ° C./0.1 Torr is obtained; [a] I ^s = + 105.8 ° (c = 1.91 in CCl ₄ ); Λ £ ^ ^{ΟΗ =} 232 πΐμ, ε = 15 500.

The mother liquor B is evaporated to separate off the acetone. 16 g of quinine salt remain, which is recrystallized from a mixture of acetone and water (5: 1). 12 g of needles with a melting point of 164.degree. C. are obtained. After another recrystallization, the melting point rises to 169.degree. The quinine salt is treated in the same way as crystallizate A. 4.7 g of dextro-trans-pyrethric acid (general formula II, b) with a boiling point of 135 ° to 140 ° C./1 Torr are obtained; [a] l ⁵ = + 88.7 ° (c = 2.13 in CCl _4); ^ ma " ⁵ ° ^{H =} 239 ηΐμ, ε = 14 700.

Claims (1)

Claim: Process for the preparation of pure dextrotrans-pyrethric acid, characterized in that the obtained by partial saponification of the dextro-trans-chrysanthemum dicarboxylic acid dimethyl ester with an approximately equimolecular amount of an alkali hydroxide or low molecular weight alcoholate in water or a low molecular weight alcohol and a mixture of dextetro-trans-pyrethric acid -trans- ^ - (2,2-dimethyl-3-methoxycarbonylcyclopropyl) methacrylic acid converted into a mixture of quinine salts with approximately the equimolecular amount of quinine in acetone, the crystalline quinine salt of dextro - trans - β - (2,2 -. Dimethyl - 3 - methoxycarbonylcyclopropyl) methacrylic acid is separated off, the quinine salt of dextro-trans-pyrethric acid is obtained from the filtrate by evaporation of the acetone and this, optionally after recrystallization, is converted with a dilute acid into the free, pure dextro-trans-pyrethric acid. Considered publications:
Journal of the Chemical Society (London), 1957, pp. 2743-2754.