1H NMR characterization of the intermediate formed upon UV-A excitation of biopterin, neopterin and 6-hydroxymethylpterin in O2-free aqueous solutions

Pterins belong to a family of heterocyclic compounds present in a wide range of living systems and participate in relevant biological functions. Under anaerobic conditions, the unstable red intermediate generated by UV-A irradiation of biopterin, neopterin and 6-hydroxymethylpterin was identified by 1H NMR analysis, in alkaline D2O solutions, as 5,8-dihydro-6-formylpterin.