Synthesis of biopterin and related pterin glycosides

Certain pterins having a hydroxyalkyl side chain at C-6 have been found as glycosidic forms in certain prokaryotes, such as 2'-O-(α-D-glucopyranosyl) biopterin from various kinds of cyanobacteria, and limipterin from a green sulfur photosynthetic bacterium. Synthetic studies on glycosides of biopterin and related pterins have been made in view of the structural proof as well as for closer examination of their biological activities and functions. The syntheses of these natural pterin glycosides have effectively been achieved, mostly through appropriately protected N²-(N,N- dimethylaminomethylene)-3-[2-(4-nitrophenyl)ethyl]pterin derivatives as glycosyl acceptors, and are reviewed here.