Evaluation of diazotized 4-amino-3, 5-dinitrobenzoic acid (ADBA) as a new derivatizing reagent

Abstract

A preliminary evaluation of the reactivity of diazot.zed 4 amino-3,5-dinitrobenzoic a d d (ADBA) towards selected aro" mane compounds has been described. Successful diazo coupling of pharmaceuticals possessing aromatic rings ofva™ mg reactivities was achieved with the arenediazoniumion^f ADBA at room (30°C) or elevated temperature 80»C) Z adducts formed in spot-test reactions were colored for some compounds(e.g cloxacillin and chloroxylenol),othersshow™ coburate elevated temperature of reaction (e.g., salicylicac!d and aspirin), while others showed no detectable change in color of reaction mixture, even at elevated temperature (e * imidazole and tinidazole). The colored product formed at room temperature decomposed and the color discharged at elevated temperature in some cases (e.g., 0-naphthol). However, thin layer chromatographic analysis suggested that a more lipophilic derivative, relative to the original compound was formed for some of the compounds studied which did not show any detectable color change in the spot test reactions. The diazotized ADBA is thus shown to be a reactive coupling reagent with which a suitable derivatization methodology could be developed for a wide range of pharmaceuticals in ultraviolet/visible spectrophotometry and high performance liquid chromatographic (HPLC) analysis.