Revisiting Hydrazine Moiety as a Scaffold for the Synthesis of Potential Antiviral Pyrazole Ribonucleoside Analogues.

Pyrazole ribonucleoside analogues were prepared via a linear approach starting with the reaction of D-ribosylhydrazine with 1,3-dicarbonyl or acrylonitrile derivatives, thereby avoiding the regio- and stereoselectivity challenges typically encountered in N-glycosylation reactions. Three series of pyrazole nucleoside analogues, as along with selected corresponding pronucleotides, were prepared and their antiviral activity against Zika virus and Sars-Cov-2 is reported.