A ring-enlarged oxetanocin A analog as an inhibitor HIV infectivity

Two ring-expanded analogues (compounds 2 and 3) of the anti-HIV fermentation product oxetanocin A (1) were synthesized from commercially available diacetone D-glucose. Antiviral testing against HIV in ATH8 cells revealed that the ring-expanded analogue 2 possessed a similar activity profile as oxetanocin A. Neither compound, however, was capable of providing full protection to the cells against HIV infection. The isomeric ring-expanded analogue 3 was totally devoid of anti-HIV activity. Molecular modeling suggested that while oxetanocin A and compounds 2 and 3 share a large common substructure with the potent anti-HIV drug, dideoxyadenosine (ddA), the extra hydroxymethyl substituent may contribute negatively to the binding of these molecules to a critical enzyme. The negative contribution may be less important in oxetanocin and isomer 2 than in isomer 3. From these studies it would appear that both oxetane and tetrahydrofuran rings are equivalent templates to support the adenine base in terms of anti-HIV activity.