Norrish type II analogous photodegradation of neopterin and biopterin to 5,8 -dihydropterin-6-aldehyde

Photoinduced Generation of H2O2 and O2•- by 6-formylpterin in Aqueous Solutions

“…Schallreuter et al demonstrated for the first time the accumulation of 6-carboxypterin in the epidermis of patients affected by this pathology and the generation of H 2 On during the photolysis of biopterin and formylpterin under aerobic conditions (19). In addition, the photooxidation of biopterin to formylpterin as previously reported by Pfleiderer et al (11,12) and the photooxidation of formylpterin to yield 6-carboxypterin as previously reported by Capparelli et al (14,15) was confirmed ( Scheme 2 ).…”

“…When solutions of 6-biopterin and neopterin, previously purged with Ar, are exposed to UV-Α radiation, red compounds are generated. It has been proposed that these compounds, with long wavelength (Àmax ~ 480 nm) absorption bands of low intensity, are 6-acyl-5,8-dihydropterins (10,11,12). Therefore the reactions observed imply the reduction of the pterin moiety and the oxidation of the substituent, through an intramolecular redox reaction.…”

Photoinduced Formation of Reactive Oxygen Species from the Acid Form of 6‐(Hydroxymethyl)pterin in Aqueous Solution

“…As soon as air (O 2 ) was let into the cell, a thermal reaction in the dark was observed, and the mentioned UV/VIS absorption band disappeared. Taking into account the studies carried out by Pfleiderer and co-workers on the photochemistry of biopterin and neopterin [21] [22] [44], and considering the spectroscopic features of related compounds like 5,8-dihydrolumazines [45] and 1,4-dihydropyrazines [46], our results suggest that, as in the case of anaerobic irradiation of the basic form 1b of HPT [23], an intermediate such as 6-formyl-5,8-dihydropterin is formed. However, the spectroscopic changes at wavelengths above 420 nm were lower than those observed during the irradiation of 1b.…”

Synthesis, Characterization of New Tungsten(IV)?Pterin Complexes and their Reactivity Studies towards Trimethylamine N-Oxide, Sodium Borohydride and Potassium Ferricyanide

“…Although the free ligand (1) is nonfluorescence, the present complexes possess intense fluorescence property (Figure 7), which can (Figure 7), which can be ascribed partly to the aromatic (oxidized) nature of the pyrimidine ring in the pterin ligand anion, L 2- (Figure 2) as well as to the overall rigidity of the chelated ligand/complex molecules, preventing dissipation of the excitation energy in manners other than by the emission of fluorescent light [35][36][37][38]. In short the fluorescence property is a good probe for understanding the overall oxidation state of the pterin ring and following its transformations [ e.g.…”