BrMOZPhC, a novel coumarin type reagent for the fluorescent derivatisation of carboxylic acids Original Research Article

A new fluorescent reagent was synthesized in order to be used as a fluorescent probe in analytical HPLC derivatisation reactions. Briefly, 2,4-dimethoxyaniline was acylated and demethylated and the resulting diphenol reacted with α-bromoacetoacetate in the presence of conc. sulfuric acid (the Von Pechmann reaction). The resulting acetamido coumarin was hydrolyzed and the aminohydroxy derivative cycled to form the corresponding bromo-coumarinoxazine. The analytical reaction was performed with butyric acid as model compound and catalyzed by 18-crown-6 ether. The calibration curve constructed was characterized by good linearity whereas the precision of the reaction gave an R.S.D. values below 3%. The reaction applied to the separation of five aliphatic acids.