Guanosine produced by fermentation is one of the nucleosides most read
ily available on an industrial scale. We have recently developed sever
al processes leading to known antiviral agents starting with guanosine
. The processes involve enzymatic transglycosylation for stavudine (d4
T), chemical transpurination for acyclovir and ganciclovir, and novel
alkylation for penciclovir and famciclovir.