Improved Industrial Syntheses of Penciclovir and Famciclovir Using N2-Acetyl-7-Benzylguanine and a Cyclic Side Chain Precursor
作者:Takayoshi Torii、Keizo Yamashita、Mitsuhiko Kojima、Yumiko Suzuki、Toyoto Hijiya、Kunisuke Izawa
DOI:10.1080/15257770600686279
日期:2006.6
We have established practical synthetic methods for penciclovir (PCV, 1) and famciclovir (FCV, 2) from N2-acetyl-7-benzylguanine (NAc7BnG, 3) and 6,6-dimethyl-5,7-dioxaspiro[2.5]octane-4,8-dione (4)-the latter being a more easily prepared cyclic precursor of the diacetate side chain (5) used in the conventional process. The coupling of 4 with 3 proceeded regioselectively at the N9 position of guanine in good yield. The coupling product was then successfully transformed into the known antiviral agents in a short number of steps.