The metabolism of aminophenols, o-formamidophenol, benzoxazole, 2-methyl- and 2-phenyl-benzoxazoles and benzoxazolone in the rabbit

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Abstract
Following the admn. of o-, m- and p-aminophenols to rabbits, they were excreted unchanged in 11, 0 and 2%, were excreted 17, 39 and 45% conjugated with acetic acid, 15, 15 and 12%, with sulfuric acid, and 65, 64 and 61% with glucuronic acid. The properties of the glucuronides isolated were not in complete agreement with those recorded in the literature. Of the administered o-formamidophenol 2% was excreted as o-aminophenol 7% unchanged, 37% acylated, 16% conjugated with sulfuric acid, and 74% conjugated with glucuronic acid. One % of the benzoxazole was excreted as o-aminophenol, 44% as acylated aminophenol, 16% as aminophenol conjugated with sulfuric acid, and 50% as aminophenol conjugated with glucuronic acid. About 14% of the dose was excreted as un-diazotizable glucuronide, i.e. hydroxylated without rupture of the oxazole ring. A hydroxybenzoxazolone (4% of dose) was isolated from urine. One % of the 2-methylbenzoxazole was excreted as o-aminophenol, 56%, as aminophenol conjugated with acetic acid 16% with sulfuric acid and 35% with glucuronic acid. About 32% of the dose was excreted as undiazotizable glucuronide. 2-Phenylbenzoxazole was excreted as free phenols to the extent of 2%, and conjugated with sulfuric acid 10% and with glucuronic acid 48%. There was no evidence of fission of the oxazole ring. A metabolite, believed to be 2-(3-hydroxyphenyl)-benzoxazole, and its glucuronide were isolated. Benzoxazolone was excreted as free phenols to the extent of 2%, and conjugated with sulfuric acid 22% and with glucuronic acid 53%. There was no evidence of fission of the oxazolone ring. A hydroxybenzoxazolone was isolated from urine and its constitution is discussed. RF values on paper chromatograms for the phenolic metabolites are recorded.
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