Fluorescent tricyclic analogues of acyclovir and ganciclovir. A structure-antiviral activity study

Of a series of new guanine base modified tricyclic analogues of acyclovir ( ACV, 1) and ganciclovir (GCV, 2), derivatives of the 3,9-dihydro-9-oxo-5H-i midazo[1,2-a]purine system, evaluated for activity against herpes simplex v irus type 1 and 2, several fluorescent analogues, 6-(4-MeOPli)-TACV (8), 7- Me-6-Ph-TACV (17), 6-(4-MeOPh)-TGCV (27), and 7-Me-6-Ph-TGCV (28), were obt ained that showed similar potency and selectivity as the parent compounds. The activity was found to Le strongly dependent on the nature and steric de mands of the substituents in the 6 and/or 7 position.