title: One-electron reduction of halothane and formation of halide ions in aqueous solutions.
abstract: Formation of Br- and, under certain conditions also F- ions has been observed in the radiation chemically induced one-electron reduction of the anesthetic halothane (2-bromo-2-chloro-1,1,1-trifluoroethane) in aqueous solutions. The initial step is the release of Br- and formation of the 2-chloro-1,1,1-trifluoroethyl radical. The latter can react via competing pathways including H-atom abstraction, addition of molecular oxygen and further reduction by an antioxidant. All of these three competitive routes lead to different product patterns. High yields of F- ions are observed under anaerobic conditions in the presence of antioxidants such as ascorbate, propyl-gallate, etc. The fluoride elimination is strongly pH-dependent and seems to occur in various steps after initiation through reduction of the (CF3CHCl) radical. The implication for biochemical studies on the metabolism of halothane under different oxygen concentrations is discussed.
mesh_terms: D000975:Antioxidants / Q000494:pharmacology; D001965:Bromides; D055598:Chemical Phenomena; D002621:Chemistry; D005459:Fluorides; D005720:Gamma Rays; D006221:Halothane / Q000031:analogs & derivatives / Q000528:radiation effects; D006863:Hydrogen-Ion Concentration; D010084:Oxidation-Reduction; D012996:Solutions; D014867:Water
chemical_list: D000975:Antioxidants; D001965:Bromides; D012996:Solutions; D014867:Water; C016800:1,1,1-trifluoro-2-chloroethane; D005459:Fluorides; D006221:Halothane