Hydrogen Exchange Reaction of Aminobenzoic Acid. I. Comparison between Wilzbach Tritiation and Acid Catalyzed Hydrogen Exchange Reaction

Abstract

Wilzbach tritiation in ortho-, meta- and para-aminobenzoic acids was compared with acid catalysed hydrogen exchange reaction and bromination. The acid catalysed hydrogen exchange reaction of the acids in 4 N DCl occurred at ortho and para to amino group of the acids and it was confirmed that the reaction was a typical electrophilic substitution. Tritium incorporation in the acids by Wilzbach labelling was high at ortho and para to amino group of the acids although the order of reactivity on Wilzbach labelling did not completely agreed with that in acid hydrogen exchange reaction. This seems to suggest that HeT⁺ ion would participate in the labelling predominantly.