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pathways open to further reaction. It can adduct to the protein,217 to give 193, react with molecular oxygen, to form the trichloromethylperoxy radical (194),216 or undergo a second one-electron reduction, to generate the trichloro-methyl anion (195), which protonates to yield chloroform (58), or eliminates a second chloride anion, to generate dichlorocarbene (196).218

Both oxidative and reductive metabolism of the general anesthetic halothane (60) have been associated with hepatotoxicity (Scheme 21). Both processes lead to covalent adduction of a reactive metabolite to various proteins. In the case of oxidative metabolism, it is the trifluoroacetylated protein 197, formed by reaction with the trifluoroacetyl chloride metabolite of halothane, as discussed earlier, while in the case of reductive metabolism it is the 2,2,2-trifluoro-1-chloroethylated protein 198, formed from reaction with the 2,2,2-trifluoro-1-chloroethyl radical, which in turn is generated from the reductive elimination of a bromide anion from halothane.214'219

5.05.3.1.2 Reduction of nitrogen-containing functional groups

Cytochrome P450 is also capable of reducing nitrogen-containing functional groups of various oxidation states back to the corresponding saturated nitrogen-containing functional group (amine, hydrazine, etc.). So, N-oxides, imines,

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