JPS6254480B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a biochemical method for producing optically active α-cyano-3-phenoxybenzyl alcohol. More specifically, it belongs to the genus Penicillium and Rhizopus, and is an organic carboxylic acid (saturated or unsaturated organic carboxylic acid having 1 to 18 carbon atoms) ester of (R S)-α-cyano-3-phenoxybenzyl alcohol. On the other hand, an esterase produced by a microorganism having an asymmetric hydrolyzing ability is allowed to act on the ester at a pH of 7 or lower to asymmetrically hydrolyze it, producing optically active α-cyano-3-phenoxybenzyl alcohol and its The present invention relates to a biochemical method for producing optically active α-cyano-3-phenoxybenzyl alcohol by obtaining an ester of its enantiomer. α-Cyano-3-phenoxybenzyl alcohol is known as a novel alcohol component of a group of ester compounds called synthetic pyrethroids, which have excellent insecticidal activity. Synthetic pyrethroids, such as fuenvalerate, cypermethrin, and deltamethrin, which contain this alcohol as an alcohol component, have dramatically increased efficacy and are resistant to sunlight, so they are useful not only for household use and epidemic prevention, but also for agricultural chemicals. It is also attracting attention as an insecticide, and therefore the importance of α-cyano-3-phenoxybenzyl alcohol is increasing. Since the α-cyano-3-phenoxybenzyl alcohol has an asymmetric carbon at the α-position, two types of optical isomers exist, and the insecticidal efficacy as an ester is higher than that of the S-form alcohol. is known to be far superior to the corresponding R-isomer (Kosuke Yoshioka, Organic Synthetic Chemistry, Vol. 38, No. 12, 1152-
1162 pages (1980)). Therefore, (R.S)-α-cyano-3 obtained by ordinary synthetic chemical production methods
It has been desired to develop a technique for optically resolving -phenoxybenzyl alcohol using an industrially advantageous method to obtain the S-form. By the way, the α-cyano-3-phenoxybenzyl alcohol is an unstable compound, and it is difficult to employ the conventional optical resolution method of alcohol via ester or half-ester with a normal optically active organic acid. Until now, (S)-(-)-α-cyano-
As a method for obtaining 3-phenoxybenzyl alcohol, (i) (R S)-α-cyano-3-phenoxybenzyl alcohol is cis-
2,2 dimethyl-3S- (dihydroxymethyl)
reacting with cyclopropane-1R-carboxylic acid lactone to form an ether compound and separating the resulting two isomer mixtures by physical means;
A method of hydrolyzing an ether compound containing a (S)-(-) alcohol component in an acidic medium to obtain the desired (S)-(-)-α-cyano-3-phenoxybenzyl alcohol (Unexamined Japanese Patent Publication No. Showa 54-109944
No.) and (ii) (S) of chiral and cyclopropane carboxylic acids
-(-)-α-Cyano-3-phenoxybenzyl alcohol ester is reacted with boron halide and then water is reacted with (S)-(-)-α-
Method for obtaining cyano-3-phenoxybenzyl alcohol (JP-A-56-12355). is only known. However, these methods also require steps, require expensive optically active reagents, and have a low total yield.
This method cannot necessarily be said to be sufficient in that it requires an ester of -cyano-3-phenoxybenzyl alcohol. The present inventors have conducted repeated research to overcome these problems and find an industrially advantageous method for producing (S)-(-)-α-cyano-3-phenoxybenzyl alcohol. , racemate i.e. (R・S)
-Using an ester of α-cyano-3-phenoxybenzyl alcohol as a raw material, by biochemically asymmetrically hydrolyzing it, optically active α-cyano-3-phenoxybenzyl alcohol and the enantiomer They found that it is possible to efficiently divide the compound into esters, and after further various studies, they have completed the present invention. That is, the present invention relates to Penicillium
Genus, belonging to the genus Rhizopus, (R.S)
- Esterase that has the ability to asymmetrically hydrolyze an organic carboxylic acid (saturated or unsaturated carboxylic acid having 1 to 18 carbon atoms) ester of α-cyano-3-phenoxybenzyl alcohol ( In the present invention, esterase refers to esterases in a broad sense, including reverses, which are active against water-insoluble ester substrates. , provides a method for producing optically active α-cyano-3-phenoxybenzyl alcohol by splitting it into optically active α-cyano-3-phenoxybenzyl alcohol and its enantiomer ester. Used as a raw material in the present invention (R・
Examples of the organic carboxylic acid component of the ester of S)-α-cyano-3-phenoxybenzyl alcohol include formic acid, acetic acid, propionic acid, butyric acid, citric acid, isochenric acid, caproic acid, caprylic acid, caproic acid, Examples include lauric acid, myristic acid, palmitic acid, stearic acid, oleic acid, linoleic acid, etc., and esters of organic carboxylic acids having 2 to 18 carbon atoms are preferred from the viewpoint of ease of handling, optical purity of the reaction product, etc. An acetic acid ester is more preferable from the viewpoint of ease of handling and economical aspects. These esters can be easily produced by a conventional method for producing esters, for example, by reacting (R.S)-α-cyano-3-phenoxybenzyl alcohol with an anhydride of an organic carboxylic acid or an organic carboxylic acid halide. can do. It can also be produced by reacting 3-phenoxybenzaldehyde with sodium cyanide and a halide of the organic carboxylic acid instead of (R.S)-α-cyano-3-phenoxybenzyl alcohol. Esterases that can be used in the present invention are esterases in a broad sense, including lipases produced by microorganisms belonging to the genus Penicillium and Rhizopus. Specific examples of this microorganism include the following strains. (1) Penicillium frequentans IFO 5692 Penicillium frequentans (2) Rhizopus chinensis IFO 4737 Rhizopus chinensis All of these strains are preserved at the Institute of Fermentation (IFO) in Osaka City, and must be obtained from this preservation institution. Can be done. The above microorganisms are cultured in liquid culture according to a conventional method, such as by inoculating the microorganisms into a sterilized malt extract liquid medium or yeast extract liquid medium, and usually at 20 to 40°C for 2 to 3 hours.
Culture with reciprocating shaking can be carried out for days, or solid culture can be carried out if necessary. When carrying out the method of the present invention, (R・S)-α-
The asymmetric hydrolysis of the organic carboxylic acid ester of cyano-3-phenoxybenzyl alcohol is carried out using an esterase-containing solution such as a culture solution, a culture filtrate, an esterase extract or a concentrate obtained by culturing the microorganism,
Alternatively, it may be carried out by mixing an aqueous solution containing crude esterase or purified esterase with the organic carboxylic acid ester of the (R·S)-alcohol, and stirring or shaking the mixture. If necessary, a non-ester surfactant may be added. It is also possible to immobilize the enzyme and use it. Further, the reaction temperature at this time is suitably 10 to 65°C, and preferably 20 to 50°C since the alcohol produced is relatively unstable to heat and the reaction rate is slow at too low a temperature. The reaction time is usually 3 to 48 hours, but the reaction time can be shortened by increasing the reaction temperature or using a highly active enzyme. Furthermore, since α-cyano-3-phenoxybenzyl alcohol is particularly easily decomposed by bases, it is important to control the pH of the aqueous solution during the enzymatic reaction. That is, even if asymmetric hydrolysis by esterase proceeds in a basic medium, the alcohol produced will undergo denaturation, so it is important to carry out the enzymatic reaction at a pH of 7 or lower. Furthermore, since the enzyme is inactivated if the pH is too low, it is preferable to carry out the reaction within the range of PH3.5 to PH6.5. Furthermore, in order to prevent the pH from decreasing due to organic acids such as acetic acid produced by hydrolysis, it is desirable to control the pH to a constant level by using a buffer solution or the like. As the buffer solution, either an inorganic acid salt buffer solution or an organic acid salt buffer solution can be used. The concentration of the ester substrate used is in the range of 1 to 80 w/w%, preferably in the range of 5 to 35%, based on the reaction solution, and the reaction can be carried out even at high substrate concentrations. Next, after performing the asymmetric hydrolysis reaction in this manner, the liberated optically active α-cyano-3-phenoxybenzyl alcohol and the unreacted enantiomer ester are separated and recovered. For this separation and recovery, operations such as solvent extraction, fractional distillation, column chromatography, etc. can be appropriately employed. For example, the reaction solution is extracted with an organic solvent such as ether, benzene, or toluene, and this extract is fractionally distilled under reduced pressure to separate optically active α-cyano-3-phenoxybenzyl alcohol and its enantiomer ester. Free optically active α-cyano-3-phenoxybenzyl alcohol can be obtained by separating or separating the extract using silica gel or the like or by column chromatography. The unreacted ester thus separated and removed can be epitomized by contacting with a basic compound such as ammonia, pyridine, triethylamine, etc., and can be used again as a raw material in the method of the present invention. Next, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited thereto. Examples 1-2 In a 500ml shoulder flask, malt extract, yeast extract liquid medium (1 part water, 5.0 g peptone, glucose
Dissolve 10.0g, malt extract 3.0g, and yeast extract 3.0g, and adjust the pH to 6.5. ) After sterilization, 2 platinum loops of each microorganism listed in Table 1 were inoculated from the slant culture and cultured at 30°C for 72 hours with reciprocal shaking. Next, each culture solution was diluted with a 2M HCl aqueous solution.
The pH was set to 5.0, and the acetate ester of (R・S)-α-cyano-3-phenoxybenzyl alcohol was 2.0.
g was added thereto, and the mixture was reacted at 30° C. for 30 hours with stirring. During the reaction, a concentration of 1M was added as the reaction progressed.
The NaOH aqueous solution is made into minute water droplets using a drop controller, and then carefully added using a PH controller.
PH was controlled constant. After carrying out the reaction for 40 hours, the reaction product was extracted with toluene. The extract was subjected to high performance liquid chromatography (HPLC) [Lichrosorb RP-
18, methanol-water (6:4), 254 nm, UV detection), acetic acid ester of α-cyano-3-phenoxybenzyl alcohol and α-cyano-3
- The hydrolysis rate was calculated from the peak area ratio with phenoxybenzyl alcohol. The extract was concentrated and subjected to silica gel column chromatography, eluted with a cyclohexane-ethyl ether (94:6) solution to separate and remove unreacted acetic acid ester of α-cyano-3-phenoxybenzyl alcohol. Elute with methanol containing a trace amount (10 ^-5 %) of para-toluenesulfonic acid.
Free α-cyano-3-phenoxybenzyl alcohol was obtained. After distilling off the elution solvent, 10 mg of the obtained free α-cyano-3-phenoxybenzyl alcohol was dissolved in 1 ml of toluene, and an equimolar amount of (S)-(+)-2-(4-chlorophenyl) was dissolved in 1 ml of toluene. )
-Isovaleric acid chloride and pyridine are added and reacted to form a diastereomer of (S)-(+)-2-(4-chlorophenyl)-isovaleric acid of α-cyano-3-phenoxybenzyl alcohol. Gas chromatography (10% DOQF-1, 2.5m, 250
Optical isomer analysis was performed at (°C). The results are shown in Table 1.

【table】

Claims (1)

[Claims] 1 Belongs to the genus Penicillium and the genus Rhizopus, and (R・S)-α-cyano-
An organic carboxylic acid (saturated or unsaturated carboxylic acid having 1 to 18 carbon atoms) ester of 3-phenoxybenzyl alcohol is treated with an esterase produced by a microorganism capable of asymmetric hydrolysis at a pH of 7 or below. , optically active α-cyano-3-phenoxy, which is characterized by asymmetric hydrolysis to split it into optically active α-cyano-3-phenoxybenzyl alcohol and its enantiomer ester. Biochemical production of benzyl alcohol.