Stability studies on 6-amidino-2-naphthyl 4-[(4,5-dihydro-1H-imidazol-2-yl)amino]benzoate dimethanesulfonate (FUT-187) in aqueous solution

Abstract

FUT-187 (I), 6-amidino-2-naphthyl 4-[(4,5-dihydro-1H-imidazol-2-yl)amino] benzoate dimethanesulfonate, is a new synthesized proteinase inhibitor. Decomposition kinetics and photoreactivity of I in aqueous solution were studied. In aqueous solution, I was hydrolyzed to its moieties, [4-(4,5-dihydro-1H-imidazol-2-yl)amino]benzoic acid (IABA) and 6-amidino-2-naphthol (AN). The hydrolysis followed a pseudo-first order reaction. I was stable under acidic condition between pH 2 and pH 3 and decomposed by irradiation from xenon light to form IABA, AN and compound II. The structure of II was studied by nuclear magnetic resonance, infrared, mass and ultraviolet spectra and identification tests. It was shown that II was 6-amidino-2-hydroxy-1-naphthyl[4-(4,5-dihydro-1H-imidazol-2-yl)amino]- phenyl ketone, benzophenone derivative, produced by photorearrangement reaction of I.