Oxidation–reduction reactions involving nitro groups in trifluoromethanesulfonic acid. Part 3. The reactions of 2-nitrobenzyl alcohol and related compounds

Abstract

2-Nitrobenzyl alcohol reacts with trifluoromethanesulfonic acid (99%) at 90 °C to give a 66% yield of 4-amino-3-carboxyphenyl trifluoromethanesulfonate 4. The reaction occurs through the intermediate formation of the C-protonated conjugate acid of anthranil N-oxide 7 and then probably involves the mono- and di-protonated forms of 2-nitrosobenzaldehyde. Under the same conditions, 2-nitrobenzyl chloride and 2-nitrosobenzaldehyde react to give the same product in essentially the same yield. Low temperature reactions in trifluoromethanesulfonic acid permit the conversion of N-phenylhydroxylamine into 4-aminophenyl trifluoromethanesulfonate in a yield of 78%.