JPS6187640A - Separation process - Google Patents

Abstract

PURPOSE:To enable the sharp separation of the enantiomer of an alpha- hydroxycarboxylic acid and/or its salt, by liquid chromatography using a filler obtained by bonding a metallic salt of an optically active amino acid to a carrier. CONSTITUTION:The optical resolution of an enantiomer of an alpha-hydroxy carboxylic acid and/or its salt (e.g. lactic acid, mandelic acid, their Na salt, Ca salt, etc.) is carried out by the liquid chromatography using a filler obtained by bonding a metallic salt of an optically active amino acid to a carrier. When a silica gel is used as the carrier, the filler is represented by the formula (at least one of Y<1>-Y<3> is a siloxane bonding group with silica gel, and the remainders are H, alkyl, aryl, halogen, OH, etc.; X is 1-20C spacer; R is metal lic salt of optically active amino acid). The mobile phase for the chromatographic separation is preferably an aqueous solution of a strong acid salt of bivalent copper, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] Acids The present invention relates to a separation method for optically resolving enantiomers of α-hydroxycarbonate salts using liquid chromatography.

[Conventional technology]

Up until now, optical resolution of α-hydroxycarboxylic acids using liquid chromatography has been carried out by Tanimura et al., Society of Analytical Chemistry, 30th Conference Abstracts, PI3 (1981), or Benecke, J. Ohromazogr.
291 (19'84), 155. These methods use a reversed-phase partitioning filler, divalent steel and optically active amino acid or optically active N,N-dialkyl abanoic acid in the mobile phase, and detect pentavalent iron. The Bosutravel detection method uses a salt solution as the coloring reagent.

[Problem that the invention seeks to solve]

However, the method described in the above-mentioned literature has the problem that an overwhelmingly large amount of the optically active substance is consumed as a mobile phase in the optical resolution of a sample containing a trace amount of the optically active substance. There is.

In addition, since the mobile phase described in the literature shows strong absorbance to ultraviolet and visible light, it is recommended to use an ultraviolet/5IpA absorption photometer (UV-VIS detection can't use [vessel],
The device has the disadvantage that a complicated boss travel detection method must be used.

[Means for solving problems]

The present inventors have conducted intensive studies on separation efficiency (filling material for liquid chromatography) 1 as a method for separating α-hydroxycarboxylic acids or in-situ enantiomers without using an optically active storage device in the mobile phase. As a result of 7IC, we found that the above problems could be solved by using a filler in which an optically active amino acid was bound to a metal group as a carrier.
The invention was completed.

The present invention is a method for separating enantiomers of α-hydroxycarboxylic acids and/or salts thereof by liquid chromatography using a packing material comprising a gold N4 salt of a photoactive amino acid bound to a carrier.

Examples of carriers used in the present invention include silica gel, porous synthetic polymers, and polysaccharides; more specifically, porous synthetic sieve molecules include styrene divinylbenzene copolymers, and acrylic esters of polyhydric alcohols. polymer of
Examples of polysaccharides include dextran and cellulose, but silica gel is most preferred.

When silica gel is used as a carrier, the filler used in the present invention is represented by the following general formula (1).

Y -8i-X-R (1 [However, in the formula, at least one of Y, Y, and Y represents silica gel and a siloxane bonding moiety with silica gel, and the rest are hydrogen and an alkyl group having 1 to 6 carbon atoms, respectively. , represents an aryl group having 6 to 14 carbon atoms, an arylalkyl group having 7 to 20 carbon atoms, a halogen, a hydroxy group, an alkoxy group having 1 to 6 carbon atoms, or any combination thereof. Represents a spacer.R
represents an optically active metal salt of an amino acid.] Any known silane treatment agent can be used to form a spacer portion of the filler represented by the above general formula (1), but specifically, 3-chloropropyl trimethoxysilane, 5-chloropropyldimethoxymethylsilane, 5-chloropropylmethyldichlorosilane, 3-
/lolopropyltrichlorosilane, 5-bromopropyldimethylchlorosilane, 5-bromopropyltrichlorosilane, 3-bromopropyltrimethoxysilane, 2-
<5.4-epoxycyclohexylethyl]trimethoxysilane, 5-glycidoxypropyltrimethoxysilane, jetoxy-5-glycidoxypropylmethylsilane, 5-glycidoxypropyldimethylethoxysilane, 8-bromo Examples include octyltrichlorosilane. Examples of metal salts of optically active amino acids include metal salts of natural or unnatural α-amino acids and β-amino acids. More specifically, alanine, arginine, asparagine, aspartic acid, cysteine, glutamic acid, histidine, inleucine, leucine, lysine, ornithine, methionine, phenylalanine, serine, threonine, )lJ7')77;/, tyrosine, valine, Examples include metal salts such as phenylglycine, florin, hydroxyproline, and allohydroxyproline. Examples of metals that form salts include divalent copper, nickel, and pentavalent cobalt.

As the separation method of the present invention, a compound represented by the general formula (Xt) is used as a packing material for liquid chromatography, and 2
It is preferable to use a water bath solution of a strong acid salt of copper, or a mixture thereof with acetonitrile and alcohol. Examples of strong acid salts of divalent copper include cupric chloride, cupric nitrate, copper sulfate, steel perchlorate, and hydrates thereof, which are used as aqueous solutions.

In the present invention, the cylindrical column used for liquid chromatography to separate enantiomers and t-hydroxycarboxylic acids and their salts may be made of glass or stainless steel, but usually has a working pressure and pressure resistance. selected from. In principle, it is possible to use any column size, but the sample injection volume, analysis time,
An appropriate one is selected from among the solvent streams-m, etc.

The packing material represented by the above general formula (11) is packed into the above column. Either dry or wet packing method is possible, but for small collars, the wet method is usually used because it can obtain a high number of theoretical plates. In other words, it is best to use the slurry method for filling.The packed column is connected to a pump and the solvent is flowed through it, but a syringe is provided between the pump and the column.
From there, inject the enantiomers to be separated into a solvent,
Splitting is done within columns. The separated enantiomers are detected by a detector installed at the outlet of the column, but any possible detection method may be used; a commonly used UV detector is often sufficient for the purpose.
Ru.

The target compound to be optically resolved according to the present invention is a racemic mixture of α-hydroxycarboxylic acids and salts thereof. Specific examples include lactic acid, mandelic acid, malic acid, glyceric acid, and their sodium salts, potassium salts, and calcium salts.

〔Effect of the invention〕

α-Hydroxycarboxylic acid is a heavy substance as an intermediate in the total synthesis of optically active substances, especially physiologically active substances, and in many cases, only one of the enantiomers is used as the heart wall. Analysis of its isomers and their isolation are necessary. The separation method provided by the present invention exhibits extremely good optical resolution ability for enantiomers of α-hydroxycarboxylic acids and their salts, and the enantiomers D and 5
The compounds are eluted with a sufficient difference in elution time, and the peaks of each component are sharply separated, so it can be advantageously used for qualitative and stationary analysis of enantiomers and their fractionation.

〔Example〕

The present invention will be described in detail below with examples, but the present invention is not limited thereto.

Synthesis Example 1 Silica gel Lichrosorb SI 100, particle size 10 μm (IC, manufactured by MerOk) is heated to 120 to 150° C. for 5 hours in vacuum and dried. 20g dry silica gel 120% anhydrous benzene
8 ml of glycidoxypropyltrimethoxysilane was added thereto, and the mixture was heated to reflux under a stream of dry nitrogen.

The methanol generated at this time should be removed from the system.
Allow time to react. After the reaction is complete, cool to room temperature and filter through a glass filter. The resulting 41% decorated silica gel was washed with water and benzene, and then dried in vacuo at 40°C. Sodium salt of L-proline 1.249 total anhydrous methanol so
Dissolve mtvc and add dC-modified silica gel 5.5
Add Nk, suspend and shake at room temperature for 4 days. The modified silica gel was washed with methanol, and 2g of sulfuric acid steel was added.
was transferred to an aqueous solution dissolved in 50 d of pure water to obtain a copper salt.

This was passed through the VV again and washed with pure water to obtain silica gel to which the copper salt of L-proline was chemically bonded.

Example 1 The filler obtained in Synthesis Example 1 was used to carry out base separation of racemic forms of α-hydroxycarboxylic acids and their salts. That is, the average particle size is 10 μm and the average pore size is 10O
A packing material consisting of a copper salt of L-proline bonded to fully porous silica gel was packed into a stainless steel column for high performance liquid chromatography (25 (to) Xo, 46+'?+),
．． 5 x 10-' M copper sulfate aqueous solution used in all solvents and distributed 1
When optical resolution was carried out on the racemic form of a-hydroxycarboxylic acid or its salt shown below at room temperature at room temperature, the following Table 1 was obtained.
The following results were obtained.

Table-1 In Table 1, k', α, and Rs are defined as follows.

As shown by the volume ratio of the weakly adsorbed enantiomers, that is, α in Table 1 and IIα of R8, there is a sufficient difference in the elution time of the 0- and L-enantiomers of each compound. Since both are observed and the peaks are completely separated, it can be seen that the method described in this 9ei is an excellent separation method that can be used for qualitative and constant loss analysis of enantiomers as well as for their preparative separation.

Claims (1)

[Claims] 1. A separation method characterized in that enantiomers of α-hydroxycarboxylic acid or/and its salts are separated by liquid chromatography using a packing material comprising a carrier bound to a metal salt of an optically active amino acid.