NMR investigation on the structure and conformation of 3′-azido-2′,3′-dideoxyribosylthymine (AZT), an inhibitor of the HIV (AIDS virus)

1H and 13C NMR study of 3′-azido-2′,3′-dideoxyribosylthymine (AZT), an inhibitor of HIV (human immunodeficiency virus) replication, has been undertaken. Modified Karplus relations have been used to obtain the molecular structure from the indirect coupling constants. NMR results are consistent with an anti glycosyl angle, a sugar pucker with equilibrium between C2′-endo and C3′-endo geometries and a predominantly g + conformation about C4′C5′ bond. These results are in variance with those obtained in the solid state by X-ray diffraction studies.