The 6-(4-alkoxycarbonylalkoxy)phenoxy-3-alkylthio-5-(fluoro-substituted)phenyl-l-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 satisfactory yields (57-93%). Their structures were clearly verified by spectroscopic data (IR, H-1 NMR, C-13 NMR, MS, Elemental analysis or X-ray diffraction crystallog...
