Synthesis of Novel 5-Hydrogenphosphonothioate Derivatives of AZT, d4T and ddI

5ʹ-hydrogenphosphonothioate derivatives of AZT, d4T, and ddI as anti-HIV prodrug candidates were synthesized in 61–76% yields under mild conditions through sequential one-pot reactions, i.e., couple of triethylammonium phosphinate with different alcohols in the presence of pivaloyl chloride (PV-Cl), following oxidation with elemental sulfur and further condensation with AZT, d4T, or ddI in the presence of PV-Cl.