Method for catalyzing vitamin A isomerization with ruthenium catalyst

Abstract

The invention provides a method for catalyzing vitamin A isomer conversion with a ruthenium catalyst. According to the method, a ruthenium compound is used as a catalyst, various vitamin A cis-isomerswith low biological activity can be converted into all-trans-isomers with high biological activity in a high proportion in the presence of an auxiliary agent, and the cis-isomers comprise 9-cis-isomers, 11-cis-isomers and 13-cis-isomers. The method has the characteristics of cheap and easily available catalyst, less catalyst dosage, mild reaction conditions, low reaction cost, high isomerizationefficiency and the like.

Description

technical field [0001] The invention belongs to the field of synthesis of chemical intermediates, and in particular relates to a method for catalyzing vitamin A isomerization with a ruthenium catalyst. Background technique [0002] Vitamin A (VA) is one of the essential vitamins for humans and animals. It is the basic substance required for the growth and development of the body, reproduction and vision, and affects the regulation of cell proliferation and differentiation. In addition to being used clinically to treat night blindness, conjunctivomalacia and xerosis cornea, it is also used as a food nutrition fortifier and animal feed additive. The structural formula is as follows. [0003] [0004] VA has a polyene structure with four conjugated double bonds on the side chain, and theoretically there are 16 cis-trans isomers, but due to steric hindrance effects, the only geometric isomers that exist in nature are all-trans without steric hindrance. body, 9-cis body, 13-c...

AI Technical Summary

Problems solved by technology

However, there are certain defects and deficiencies in these three methods: the iodine-catalyzed scheme can only promote the conversion of the 11-cis isomer to the all-trans isomer, and the reaction process produces a large amount of iodine-containing wastewater, which is harmful to the environment. Severe pollution (US3384633); photosensitizers are often used in the photocatalytic process as cocatalysts to convert isomers, this method can convert 9-cis isomers to all-trans isomers, but the reaction process uses The residual photosensitizer found in the product will affect the chromaticity and shelf life of VA crystals (US03838029); there are relatively more reports on the use of metal catalysts to catalyze the conversion of VA isomers, such as the use of Pd catalysts to promote the conversion of 11-cis isomers to all The conversion of trans isomers (US04051174), but the reaction process is accompanied by a large amount of generation of 9-cis isomers, and the utilization rate of raw materials is not high; Patent CN109731612A has reported the use of metal ionic liquids as catalysts in the wittig reaction to improve the completeness of the product The method of trans-vitamin A content, but the metal catalyst (iodide) of this scheme can only carry out the conversion of isomer in the wittig reaction system, promptly can only complete the higher 11-cis isomerization in the wittig reaction system Transformation of isomers, and after leaving the wittig reaction system, the transformation of related vitamin A isomers can no longer be carried out, and the cis isomers in the mother liquor after vitamin A crystallization and separation cannot be transformed again

[0007] In summary, the currently reported methods for catalyzing the conversion of cis vitamin A isomers to all-trans isomers have certain limitations, such as only a single cis isomer can be converted to all-trans isomers. body, low utilization rate of raw materials, more waste water generated by the reaction, or residual photosensitizer in the crystal, etc.

Images