| 摘要 |
<p>Amides formed between optically active carboxylic acids and (/sB) or (-)-2-dehydroemetine and acid addition salts thereof are prepared by reacting (/sB)-2-dehydroemetine with the appropriate optically active acid, or with a functional derivative thereof such as acid halide, anhydride, or activated ester, and when required the amide or a salt thereof is subjected to fractionation to separate the amides of (+) and (-)-2-dehydroemetine or their acid addition salts for example by fractional crystallization, column chromatography, thin layer chromatography or mechanical separation, and decomposing the (-)-amide produced to form (-)-2-dehydroemetine by alkaline hydrolysis. Suitable optically active acids are mandelic, tartaric, chlorophenylacetic, phenylalanine, tyrosine and benzyl penicillin. Free hydroxy or free amino groups in the amino acids must be protected for the amide formation step, for example, a hydroxy group is protected as an acyloxy group or arylmethylether group, and an amino group is protected as an N-aryl methyl, N-trityl, or N-arylkoxycarbonyl group, and the protecting group removed after amide formation, for example, by hydrolysis or hydrogenation. a -chlorophenylacetylchloride is prepared by action of thionyl chloride in dimethylformamide on a -chlorophenylacetic acid.</p> |
