The 6-(4-alkoxycarbonylalkoxy) phenoxy-3-alkylthio-5-(fluoro-substituted) phenyl-1- phenylpyrazolo [3, 4-d] pyrimidin-4-ones 6 have been successfully synthesized via a tandem aza-Wittig and annulation reactions of the corresponding iminophosphorances 4, aromatic isocyanate, and substituted phenols 2 in 59–69% isolated yields using actonitrile as solvent. These novel compounds 6 could be oxidized to sulfones 7 by hydrogen peroxide in ...