N, N'-Dicyclohexyl-およびN, N'-Diisopropyl-O-(7-methoxycoumarin-4-yl)methylisoureaによるケトカルボン酸のけい光ラベル化反応

抄録

A fluorescent labeling method has been developed for the determination of α-ketocarboxylic acids (pyruvic acid, α-ketobutyric acid and phenylpyruvic acid). Their reactions with N, N'-dicyclohexyl- and N, N'-diisopropyl-O-(7-methoxycoumarin-4-yl)-methylisourea (DCCI and DICI) in the presence of N, N-dimethylhydrazine in acetonitrile at 80°C for 1 h yielded (7-methoxycoumarin-4-yl) methyl esters of α-substituted α-(N, N-dimethylhydrazono) acetic acid (IIIa-c). Thin-layer chromatographic separation and fluorescence measurement of the esters allow the determination of α-keto acids at concentrations as low as 1-150 n mol/ml. Levulinic acid (γ-keto acid) reacted with DCCI and DICI as well as monocarboxylic acids to give the corresponding ester in a good yield.