title: Isoxazoles V: chemical stability of diisoxazolylnaphthoquinone in aqueous solution.
abstract: The hydrolytic degradation of 2-(3,4-dimethyl-5-isoxazolylamine)-N-(3,4-dimethyl-5-isoxazolyl )-1,4- naphthoquinone-4-imine (1) was investigated over a wide range of pH values and at different temperatures. The degradation rates were determined by reversed-phase HPLC and were observed to follow pseudo-first-order kinetics with respect to the concentration of 1. The pH-rate profile was linear with slopes -1 and +1 in acid and alkaline pH, respectively, becoming pH independent in the region of maximum stability from pH 4.5 to 10.0. Neither primary salt effects nor buffer catalysis was observed due to the buffer species employed.
authors.affiliation: Departamento de Farmacia, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Argentina.
authors.forename: M R
authors.initials: MR
authors.lastname: Longhi
authors.forename: M M
authors.initials: MM
authors.lastname: de Bertorello
authors.forename: M C
authors.initials: MC
authors.lastname: Briñon
mesh_terms: D002384:Catalysis; D055598:Chemical Phenomena; D002621:Chemistry; D002851:Chromatography, High Pressure Liquid; D004355:Drug Stability; D006863:Hydrogen-Ion Concentration; D007555:Isoxazoles / Q000032:analysis*; D007700:Kinetics; D010080:Oxazoles / Q000032:analysis*; D013696:Temperature
chemical_list: D007555:Isoxazoles; D010080:Oxazoles; C060422:2-(3,4-dimethyl-5-isoxazolylamine)-N-(3,4-dimethyl-5-isoxazolyl)-1,4-naphthoquinone-4-imine