A 15N study of the ammonia‐induced deamination of 1‐aminopurinium salts

Abstract Reaction of 1‐aminoadeninium mesitylenesulfonate (1) and 1,2‐diaminopurinium mesitylenesulfonate (8) with methanolic ammonia for 17 h at 100°C leads to deamination at N(l), yielding adenine and 2‐aminopurine, respectively, as well as dideamination, yielding purine. It is very likely that 6‐hydrazinopurine is formed in the dideamination of 1 and that 2‐hydrazinopurine is an intermediate in the dideamination of 8. From both hydrazinopurines, purine is formed. Labelling studies, using 15N‐labelled methanolic ammonia, show that, in the deamination reactions, a ring‐opening reaction (ANRORC mechanism) is involved.