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    • 9. 发明授权
    • Preparation of riboflavin
    • 核黄素的制备
    • US4567261A
    • 1986-01-28
    • US570457
    • 1984-01-13
    • Hansgeorg ErnstWolfram SchmidtJoachim Paust
    • Hansgeorg ErnstWolfram SchmidtJoachim Paust
    • C07D475/14C07D475/02
    • C07D475/02
    • Riboflavin of the formula I ##STR1## is prepared by condensing a 4,5-dimethyl-N-(D)-ribityl-2-phenylazoaniline of the formula II ##STR2## where R is H or --Cl, --NO.sub.2 or --CH.sub.3 in the o- or p-position, with barbituric acid of the formula III ##STR3## in the presence of an acid as the condensing agent, by an improved process in which the acidic condensing agent used is an aliphatic or cycloaliphatic/aliphatic tertiary carboxylic acid of the general formula IV ##STR4## where R.sup.1, R.sup.2 and R.sup.3 are each a lower alkyl group, R.sup.1, R.sup.2 and R.sup.3 together containing 3 to 20, preferably 3 to 10, carbon atoms, or R.sup.1 is a lower alkyl group, in particular methyl, and R.sup.2 and R.sup.3 together form a tetramethylene or pentamethylene group.The process can be particularly advantageously carried out using trimethylacetic acid or a commercial mixture of saturated tertiary carboxylic acids, e.g. Versatic .sup.R 10-acid.
    • 式I(I)的核黄素通过将式II的4,5-二甲基-N-(D) - 二乙基苯基偶氮苯胺(II)缩合制备,其中R是H或-Cl ,在邻位或对位的-NO 2或-CH 3与通式III的巴比妥酸(III)在作为缩合剂的酸存在下,通过改进的方法,其中使用酸性缩合剂 是通式IV(IV)的脂族或脂环族/脂肪族三羧酸,其中R 1,R 2和R 3各自为低级烷基,R 1,R 2和R 3一起含有3至20,优选3至10, 碳原子,或R 1是低级烷基,特别是甲基,R 2和R 3一起形成四亚甲基或五亚甲基。 该方法可以特别有利地使用三甲基乙酸或饱和叔羧酸的商业混合物,例如, 通用R10酸。