Para-aminophenol sulfate

Formulas Monomethyl para-aminophenol sulfate para-Methylaminophenyl sulfate. 

Paracetamol (known as acetaminophen in the USA) is N-acetyl-para-aminophenol (Figure 25.11). It has the same detoxification pathways as phenol and also carries the risk of inducing methemoglobinemia. To be on the safe side, it should not be used as an intravenous analgesic during a full-face phenol peel, so as not to saturate the detoxification pathways. Paracetamol is also an intermediate in the pathway for detoxification of aniline derivatives, before hepatic glucuronide and sulfate conjugation allow them to... 

As well as these traditional aqueous acid rearrangement conditions, Ratnam and coworkers have shown that the reaction can take place on solid acid catalysts, such as beta zeolite, KIO clay, sulfonated sUica, and sulfated zirconias [65]. In their work, the rearrangement of A-phenylhydrox-ylamine to para-aminophenol was investigated, in water at 80°C, using a series of these solid acid catalysts, and it was found that both the activity and selectivity are affected by the choice of the catalyst used, and the rate constant shows a linear dependence on the number of acid sites [65]. 

Hydroxylation of arylamines with persulfate ion, or Boyland-Sims oxidation, gives ortho-substituted aminophenols in good yields [29]. As with the Elbs oxidation, the procedure is also carried out in two steps - first, treatment with the oxidant to obtain an aminophenyl sulfate ester and, second, hydrolysis to obtain the final product. Primary, secondary and tertiary amines can all be used in this reaction. The ortho product is formed, except when no ortho-positions are available, which leads to para-substitution. Electrophilic attack on the ipso-carbon is believed to be the most likely mechanism, although minor radical pathways also seem to be present. 

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