Design and synthesis of α-carboxy phosphononucleosides

Rhodium catalyzed O-H insertion reactions employing α- diazophosphonate 20 with appropriately protected thymidine, uridine, cytosine, adenosine and guanosine derivatives leads to novel 5′-phosphononucleoside derivatives. Deprotection led to a novel series of phosphono derivatives bearing a carboxylic acid moiety adjacent to the phosphonate group with potential antiviral and/or anticancer activity. The phosphononucleosides bearing an α-carboxylic acid group are envisaged as potential diphosphate mimics. Conversion to mono- and diphosphorylated phosphononucleosides has been effected for evaluation as nucleoside triphosphate mimics. Most of the novel phosphononucleosides proved to be inactive against a variety of DNA and RNA viruses. Only the phosphono AZT derivatives 56-59 showed weak activity against HIV-1 and HIV-2.