Acyclic analogs of nucleosides. Synthesis of hydroxyalkylbenzimidazoles and -benzotriazoles

A Facile Synthesis of 9-(1,3-Dihydroxy-2-propoxymethyl)guanine (Ganciclovir) from Guanosine

“…21 We now wish to report an efficient synthetic route to ganciclovir (6) from inexpensive and readily accessible guanosine, using one kind of protection, acetyl groups, for all reactive functions of substrates. The acyclic sugar analog was prepared in reaction of 1,3-dichloro-2-(chloromethoxy)propane 22,23 with an excess of potassium acetate, which gave 1,3-diacetoxy-2-(acetoxy-methoxy)propane (2) in 71% yield. This compound may also be obtained in two steps from 4-chloromethyl-1,3-dioxolane.…”

“…9-(2',3',5'-Tri-O-acetyl-b-D-ribofuranosyl-N 2 -acetylguanine (1)was prepared according to Reese and Saffhill,25 and then precipitated by addition of its solution in CHCl 3 to Et 2 O giving 1 as a white powder. 1,3-Dichloro-2-(chloromethoxy)propane was obtained from 1,3-dichloropropan-2-ol.22,23 Melting points: Laboratory Devices Mel-Temp II micromelting point apparatus (uncorrected). UV spectra: Beckman DU-65 spectrophotometer.…”