Synthesis and anti-herpes virus activity of acyclic 2'-deoxyguanosine analogs related to 9-[(1,3-dihydroxy-2-propoxy)methyl]guanine

Abstract
Several "sugar" modified acyclic nucleoside analogues related to 9-[(1,3-dihydroxy-2-propoxy)methyl]guanine (DHPG,2) were synthesized and evaluated for antiviral activity. The preparation generally involved the condensation of the acetoxymethyl ether of alchols 6c-g and 10-12a with diacetylguanine to give adducts 7c-g and 14-16, which were then deprotected to afford analogues 9c-g and 17-19. Alternatively, alcohols 12a and 13a were converted to iodides via their tosylates 12b and 13b and then reacted with the sodium salt of guanine to afford, after deprotection analogues 22 and 23. A crossed aldol-Cannizzaro reaction on aldehyde 27 readily afforded 28, which was deprotected to give analogue 29. An in vitro assay against HSV-1 showed that all compounds tested were less active than DHPG, though several were good substrates for the viral thymidine kinase. The more promising acyclic nucleosides 9c, 19, and 29 were evaluated in a mouse encephalitis model and proved ineffective at preventing death at dose of 20 mg/kg.