Synthesis of Sepiapterin

Abstract

Sepiapterin was synthesized by the reaction of α-keto-β-hydroxybutyric acid and 7, 8- dihydropterin(Na salt) in the presence of zinc chloride. The reaction products were the mixture of two yellow compounds ((I) and (II)), which could be separated by chromatography on cellulose and Sephadex columns. Both compounds gave the same molecular formula, C₉H₁₁O₃N₅. From UV, NMR and ORD spectral data as well as chemical reactions, the structures of the compounds were proved to be 2-amino-4-hydroxy-6-(d, l-lacty1)-7, 8-dihydropteridine (I)and 2-amino-4-hydroxy-16-(1'-hydroxy-2'-oxopropy1)-7, 8-dihydropteridine (II). (I) was a mixture of sepiapterin and its stereoisomer (each, 50%) this was proved by the action of sepiapterin reductase.
The reaction of 7, 8-dihydropterin and a-hydroxyacetoacetic acid gave solely the compound (II).