5-Bromo and 5-fluoro-2',3'-dideoxycytidine have been found to be active in the DTP anti-HIV screening program at FCRF. 2'-Fluoro-2',3'-dideoxyarabinosyl adenine is not only as active and potent as ddA in anti-HIV tests, it is completely stable to the acid catalyzed glycosidic cleavage which occurs so rapidly with ddA. Oral studies in the dog showed 83% bioavailability for the fluoro analogue but only 30% for ddA. Two five-member ring analogues of the fermentation product, oxetanocin, were prepared. The first had no cellular protective properties. The second is under evaluation.
