Self‐catalytic mechanism of prebiotic reactions: II. From urea and glycinamide to hypoxanthine

Abstract

Mechanisms of reactions for formylation of urea, leading to N,N′‐diformylurea, and for the dehydration of glycinamide and N,N′‐diformylurea, yielding hypoxanthine, are suggested. It is shown that these reactions are self‐catalyzed. The first is catalyzed by formic acid, while the second is catalyzed by N,N′‐diformylurea. The suggested reaction mechanism shows that the N3 and N9 atoms of hypoxanthine originate from urea in agreement with available 1H NMR experimental data by Lagoja and Herdewijn (Lagoja & Herdewijn, Chem. Biodiv. 2004, 1, 106). A complete reaction pathway of prebiotic reactions for formation of the hypoxanthine from urea, formic acid, and glycinamide in formamide, where formamide/formimidic acid plays the role of a proton‐carrying catalyst, is also suggested.