Structural Elucidations of Pyrano[3,2-g]pteridine Derivatives by 2D NMR Spectroscopy†

Pterin derivatives are natural materials biosynthesized from guanosinetriphosphate (GTP) in biological systems and generated from all living things in the nature. Biopterin was reported as a 6-(D-erythro-1,2-dihydroxypropyl)pterin isolated from human’s urine.1 Its biosynthetic pathway has been paid attention as they play an important role in amino acid hydroxylation as a tetrahydroform. Atypical phenylketouria disease is caused by the defect of biosynthetic process for tetrahydrobiopterin.2,3 Neopterin was identified as a 6-(D-erythro-1,2,3-trihydroxypropyl)pterin from larva of bee, royal jelly4,5 and human’s urine.6 Neopterin was synthesized by Viscontini Reaction of 2,5, 6-triamino-pyrimidin-4(3H)-one and D-arabinose phenyl-hydrazone, with more than 80 % of yield,7 while biopterin was obtained from the reaction of 5-deoxy-L-arabinos