Synthesis of an AZT-HEPT Hybrid and Homologous AzddU Derivatives

3'-Azido-2',3'-dideoxyuridines 6 and their corresponding alpha anomers 5 were synthesized by condensation of silylated 6-alkyl and 5,6-dialkyl substituted uracils 2 with methyl 3-azido-5-O-tert-butyldiphenylsilyl-2,3-dideoxy-alpha, beta-D-erythro-pentofuranoside (4). Compounds 5 and 6 were treated with tetrabutylammonium fluoride to obtain the deprotected nucleosides 7 and 8, respectively.