JPS59122947A - Liquid-chromatographic analysis of mixture comprising mirror-image isomers of alpha-phenyl fatty acid esters - Google Patents

Abstract

PURPOSE:To directly resolve a mixture comprising mirror-image isomers of alpha- phenyl fatty acid esters to perform the simple and accurate analysis thereof, by performing liquid chromatograph using a stationary phase grafted with an optically active N-acylated amino acid. CONSTITUTION:By liquid chromatography using a packing obtained by grafting an inorg. carrier having OH groups on the surface thereof with an optically active organosilane represented by the formula I [wherein R1, R2 and R3 are each alkyl, alkoxy, OH or halogen and at least one of them is alkoxy or halogen, R4 is lower alkyl or phenyl, n is 2-4, X is -NHCO- or -N<+>H3OCO- and means an asymmetric carbon], a mixture comprising mirror-image isomers of alpha-phenyl fatty acid esters each represented by formula II [wherein Y is H or halogen, R is lower alkyl, A is (substituted) aryl or alkyl and means an asymmetric carbon] is directly and accurately resolved into respective isomers to perform quantitative analysis.

Description

Detailed Description of the Invention The present invention is based on the general formula CI) RO (wherein, Y represents a hydrogen atom or a halogen atom, and 鈮 represents a lower alkyl group. A represents an optionally substituted aryl group or a substituted represents an optionally aralkyl group.

This represents an asymmetric carbon. ) This relates to an analytical method characterized in that an enantiomeric mixture of α-phenyl fatty acid esters represented by .

α-Phenyl fatty acid esters exhibit excellent effects as synthetic pyrethroid insecticides, and excellent insecticides such as fenvalerate have been developed. In addition, it is known that these esters have different physiological activities based on the enantiomers of the acid component. Two enantiomers of the component 2-(4-chlorophenyl)isovaleric acid and the alcohol component α-cyano-
There are a total of four isomers of 3-phenoxybenzyl alcohol, which are a combination of two enantiomers, and the ester obtained from S-type acid and S-type alcohol has the highest insecticidal efficacy. . Therefore, various attempts have been made to increase the activation of these esters by optical resolution, and analysis of their optical isomers is essential for quality control and efficacy evaluation, and it is necessary to develop accurate analytical methods. It's been happening.

However, until now, there has been no known report on the direct separation of optical isomers of these compounds by chromatography. Therefore, at present, the analysis of optical isomers of α-phenyl fatty acid esters involves hydrolyzing the esters to obtain α-phenyl fatty acids or derivatives thereof.
This is dehydrated and condensed with optically active alcohols and amines,
These acids are analyzed as diastereomers, or are separated and analyzed as acid amides by reacting these acids with amines using gas chromatography or liquid chromatography using an optically active stationary phase. Furthermore, a method has been adopted for the above-mentioned fenvalerate, in which optically active menthol is reacted with the fenvalerate, and 94 isomers are separated and analyzed by liquid chromatography. However, these methods have many problems such as isomerization during the photoamidation reaction with high optical purity. Therefore, if it were possible to directly separate and analyze the optical isomers of α-phenyl fatty acid esters, it would be extremely advantageous.

Under these circumstances, the present inventors conducted extensive studies and found that when a packing material grafted with an optically active N-acylated amino acid was used as a stationary phase in liquid chromatography, α-phenyl The present invention was completed based on the discovery that enantiomeric mixtures of fatty acid esters can be directly separated and analysis of the mixing ratio of isomers, that is, analysis of optical purity, can be carried out easily and accurately. It is something that

The filler grafted with an optically active N-acylated amino acid used in the method of the present invention may be, for example, a filler of the general formula (II) (wherein, R2 and R,s are the same or different cy, alkyl groups, represents an alkoxyl group, a hydroxyl group, or a halogen atom, at least one of which is an alkoxyl group or a halogen atom, R4 represents a lower alkyl group or a phenyl group, and n is an optically active organosilane represented by 2 to 4. A specific example is a chromatographic packing material in which N-(
Examples include silica gel to which 3,5-dinitrobenzoyl)-〇-phenylglycine or N-(3,5-dinitrobenzoyl)-L-valine is grafted via ω-aminopropylsilane.

When preparing the filler, the method of Pirkle et al. (
J, Chromatogr., 192, 143 (1
980) e J-Org-Chem, 46, 2
935 (1981), J. Am. Chem.

Soc, 3964, (1981)'
) can be applied, for example, optically active N-
A method in which an organosilane obtained by a reaction between an acylated amino acid and an ω-aminoalkylsilane is grafted onto an inorganic carrier such as silica gel, and an ω-aminoalkylsilane is grafted onto an inorganic carrier such as silica gel in advance, and optically active N -Acylated amino acids can be prepared by multiple bonding or ionic bonding with dehydration condensation.

The packing material grafted with an optically active N-acylated amino acid used in the method of the present invention is packed into a chromatographic column according to a conventional method and used as a stationary phase in liquid chromatography. The stationary phase can be prepared by filling a chromatographic column with a packing material grafted with ω-aminoalkylsilane in advance using a conventional method, and then flowing a solution of an optically active N-acylated amino acid through the column. , optically active N- through ionic bonding
It can also be prepared by a method of immobilizing acylated amino acids.

In liquid chromatography using the stationary phase of the present invention, separation and analysis of enantiomeric mixtures of esters of σ-phenyl fatty acids can be achieved by selecting appropriate elution conditions, especially commonly used normal phase partition conditions. can be performed with good separation power (and in a short time).

Hereinafter, the present invention will be specifically explained with reference to Examples, but the present invention is not limited to these Examples. After filtering out insoluble matter, the solvent was distilled off under reduced pressure. Two hundred grams of 5% aqueous sodium bicarbonate solution was added to the residue, and after occasional shaking, the mixture was allowed to stand overnight. After insoluble matter was filtered off, the filtrate was washed twice with ether 5O-, and then 1% hydrochloric acid was added to adjust the pH to 5.0.

The precipitated crystals were dissolved in 20ml of ethyl acetate, and the ethyl acetate layer was washed three times with 50ml of water, then dehydrated over anhydrous sodium sulfate, and the solvent was distilled off under reduced pressure. The residue was recrystallized from a mixed solvent of tetra-9hydrofuran-n-hexane (5:1) to yield N-(3,5-dinitrobenzoyl)-D-phenylglycine 10F! I got it.

Melting point: 215-217°C [α]: -89.6° (C=0.93%
, tetrahydrofuran) elemental analysis C information I H
(H) N Sorry) Actual measurement value 51.97 3゜12
12.29 Calculated value 52.1B 3.21 12
．． 17 (as C15HllNsOy) Next, ω-aminopropyl silylated silica gel for high performance liquid chromatography (particle size 5μ”, pore size 60A) 3
9 was added with 50ml of dehydrated tetrahydrofuran, degassed under reduced pressure, and then N-(3,5-dinitrobenzoyl)-D
-Phenylglycine 3F and N-ethoxycarbonyl-2-ethoxy-1,2-dihydroquinoline 2 were added and stirred at room temperature for 2 hours.

The reaction solution was filtered through a glass filter, and the obtained silica gel carrier was washed on the filter with tetrahydrofuran, methanol, acetone, and ether in this order, and dried under reduced pressure to obtain N-(3,5-dinitrobenzoyl)D-phenylchrysine. The desired filler grafted via the -aminopropylsilyl group was obtained.

The elemental analysis values for this are N: 2.43%, C: 9.02
It was %.

The filler thus obtained has an inner diameter of 4% and a length of 30 mm.
The slurry was packed into a stainless steel column of 5 cm, and (t)-α-cyano-3-phenoxybenzyl (
)-2-(4-chlorophenyl)isovalerate (fenvalerate) was analyzed, and the chromatogram shown in Figure 1 was obtained.

In Figure 1, peak number (1) is (+)-α-cyano-3
-Phenoxybenzyl (t)-2-(4-chlorophenyl)invalerate (abbreviated as (t)-in) form. below,
Other isomers are also abbreviated. ), (2) is (c)
-←) body, (3) is the (he)-(t) body, and (4) is the (+)-←) body. The time required for peak (1) to elute is approximately 32 minutes; (1) and (2)
The separation coefficient of both peaks is 1.09, and the area ratio of the peaks is 5.
0:50, (the separation coefficient of both peaks 31 and (4) was 1.11, and the area ratio of the peaks was 50:50.

Example 2 Using the column obtained in Example 1, the following compounds were analyzed under the following conditions to determine the separation coefficient.

The results are shown in the table below.

[Brief explanation of the drawing]

FIG. 1 is a chromatogram obtained in Example 1, in which the vertical axis represents intensity and the horizontal axis represents retention time.

Claims (1)

[Claims] (1) General formula (wherein Y represents a hydrogen atom or a halogen atom, k
represents a lower alkyl group. A represents an optionally substituted aryl group or an optionally substituted aralkyl group. Kano represents asymmetric carbon. An analytical method characterized in that an enantiomeric mixture of α-phenyl fatty acid esters represented by the following formula is analyzed by liquid chromatography using a stationary phase grafted with an optically active N-acylated amino acid.
3゜(2) The stationary phase grafted with an optically active N-acylated amino acid has the general formula (wherein R1, R2 and R3 are the same or different groups,
It represents an alkyl group, an alkoxyl group, a hydroxyl group, or a halogen atom, and at least one is an alkoxyl group or a halogen atom. R4 represents a lower alkyl group or a phenyl group, and n is an integer from 2 to 4. The first claim is a chromatographic packing material in which X represents an -NHCO- group or an -NH30GO- group, and an optically active organosilane hexahydroxyl group on the surface thereof is grafted onto an inorganic carrier. Analysis method described in Section 1.