Optically active acetylene polymer, membrane thereof and optical

Details Optically active acetylene polymer, membrane thereof and optical Optically active acetylene polymer, membrane thereof and optical

1994-12-27

1995-09-12

Hoke, Veronica P.

Synthetic resins or natural rubbers -- part of the class 520 ser

Synthetic resins

Polymers from only ethylenic monomers or processes of...

556489, 562401, 562402, C07F 708, C07F 3008

Patent

active

054497280

DESCRIPTION:

BRIEF SUMMARY
(FIELD OF THE INVENTION)

This invention relates to a novel optically active acetylene polymer, a membrane thereof and an optical resolution method using the same.


(DESCRIPTION OF THE PRIOR ART)

Many of organic compounds have an asymmetric center. Such an organic compound has optical isomers arising from the asymmetric center. Among optical isomers, optical antipodes (enantiomers) scarcely differ from each other in physical properties including boiling point and solubility. However, it is frequently observed that these antipodes largely differ from each other in physiological activities. It is therefore highly useful in the fields of, for example, drugs, agricultural chemicals and foods to obtain one of the optical isomers (D- or L-form).
In the case of glutamic acid, for example, the L(S)-form has a deliciousness but the D(R)-form lacks any deliciousness. In the case of asparthame which is a sweetener, it is said that the S-form exhibits a sweetness while the R-form exhibits a bitterness.
In the case of drugs, as well, it is sometimes observed that the D-form of a compound significantly differs from the L-form of the same compound in drug effect and toxicity. Accordingly, the Ministry of Health and Welfare describes in the Guide to Drug Manufacturing (1985) that "when the compound exists as a racemic modification, it is desirable to examine the absorption, distribution, metabolism and excretion behaviors of each isomer."
To meet these social needs, there have been devised various means for obtaining optically active forms from racemic modifications.
As examples of methods for obtaining an optically active form from a racemic modification, preferential crystallization, diastereomer method, enzymatic method, chromatographic method and membrane separation technique may be cited.
The preferential crystallization is a method which comprises inoculating a supersaturated solution of a racemic modification with desired crystals, allowing the development exclusively of the inoculated crystals and then precipitating them. Although this is an excellent method, only limited results have been brought thereby. This is because when a racemic modification is to be resolved by the preferential crystallization, it is necessary to examine whether the following factors are satisfied or not: (1) the solubility of the racemic modification in a specific solvent is higher than that of both optical isomers; (2) the melting point of the optically active forms is higher than that of the racemic modification; (3) the optically active forms are insoluble in the supersaturated solution of the racemic modification; and (4) the IR spectra of the racemic modification agree with those of the optically active forms [see Hiroshi Yamanaka and Yasuhisa Tashiro, Kikan Kagaku Sosetsu (Quarterly Survey of Chemistry), No. 6, pages 4-5 (1989)]. Further, it is an important technical problem in the preferential crystallization to timely effect the solid/liquid separation and to shorten the filtration time. Under these circumstances, it may be said that the preferential crystallization is a technique which is applicable exclusively to special crystals, in other words, special compounds.
The diastereomer method is a technique which comprises treating a racemic modification with an optically active acid or base to thereby form optical isomer salts being diastereomeric with each other and separating these optical isomer salts by fractional crystallization by taking advantage of the difference in solubility between these optical isomer salts formed. This method is accompanied by a difficulty in the selection of the resolving agent (the above-mentioned optically active acid or base) capable of easily forming salts or derivatives with the racemic modification. This method also suffers from restrictions such that an optically active form having a high purity can be hardly obtained thereby and that the resolving agent should be used in an equivalent amount to the racemic modification.
In the optical resolution method with the use of an enzyme, the stereos

REFERENCES:
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patent: 4800162 (1989-01-01), Matson
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The Guide To Drug Manufacturing, Japan, pp. 97 and 98 (1985).
Kikan Kagaku Sosetsu, (Quarterly Survey of Chemistry), No. 6, 4-5 (1989).
Biotechnology of Amino Acid Production, vol. 24, pp. 269 to 279, Kodansha Ltd., and Elsevier Science Pub. (1986).

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