Syntheses of optically active monapterin, 7,8-dihydromonapterin, and 5,6,7,8-tetrahydromonapterin from l-xylose

Abstract

We describe the syntheses of monapterin, dihydromonapterin and tetrahydromonapterin in optically active forms. The syntheses involved the condensation of L-xylose with phenylhydrazine, providing a hydrazone derivative. The reaction of the resulting hydrazone with triamino-pyrimidinone followed by oxidation of the resulting pteridinone with molecular oxygen furnished pterin containing a hydroxylated side chain. Hydrogenation of the pterin derivatives over RANEY® Ni catalyst afforded dihydromonapterin and tetrahydromonapterin in optically active forms. We also investigated an alternative route involving an Amadori rearrangement, followed by the Polonovski–Boon reaction as the key step to make these monapterin derivatives.