SYNTHESIS AND IN VITRO ANTIBACTERIAL ACTIVITY OF NOVEL 5′-O-ANALOG DERIVATIVES OF ZIDOVUDINE AS POTENTIAL PRODRUGS

ABSTRACT

An efficient, short synthesis of four potential prodrugs of 3′-azido-3′-deoxythymidine (AZT) and their antibacterial activity are reported. The 5′-OH group of AZT was functionalized with oxalyl chloride obtaining an acyl chloride derivative (AZT-Ox), which by further transformation with leucine, isoleucine and valine amino acids led to the corresponding AZT analogs, namely AZT-Leu, AZT-iLeu and AZT-Val. A carboxyl acid derivative (AZT-Ac) was also obtained by hydrolysis of AZT-Ox. These compounds, which exhibit anti HIV activity, have killed collection and clinical strains of some opportunistic infectious agents in AIDS-related complex. Thus, the clinical strains, K. oxytoca, S. typhi and K. pneumoniae, and collection strain K. pneumoniae ATCC 10031 showed sensitivity to antibiotics. The activity order for the studied compounds against the most sensitive strain (K. pneumoniae ATCC 10031) was AZT-Leu > AZT-iLeu > AZT-Val > AZT-Ac > AZT. On the other hand, the activity order for the second most sensitive strain (K. oxytoca) was AZT-Leu > AZT-Val=AZT-Ac > AZT-iLeu > AZT. The most effective antibacterial drug AZT-Leu, M.I.C.=0.125 µg mL⁻¹) was 16 times more active than AZT (AZT, M.I.C.=2 μg mL⁻¹) against K. pneumoniae ATCC 10031. Thus, this compound may therefore have better clinical potential than AZT for the treatment of AIDS-related complex.

ACKNOWLEDGMENT

The authors gratefully acknowledge the Agencia Nacional de Promoción Científica, the Agencia Córdoba Ciencia and the Secretaría de Ciencia y Técnica de la Universidad Nacional de Córdoba (SECYT-UNC) of Argentina for financial support. The authors also wish to express their sincere thanks to Dra. L. Alassia (FILAXIS Laboratories, Buenos Aires, Argentina) for supplying zidovudine. G.N.M. acknowledges receipt of a fellowship granted by the Consejo de Investigaciones Científicas y Technológicas de la Provincia de Córdoba (CONICOR.)