Conjugated azoalkenes. Part XI. Direct synthesis of substituted pyrazoles and 4-triphenylphosphoranylidene-4,5-dihydropyrazol-5-ones by heterocyclization of some zwitterionic 1,4-adducts between conjugated azoalkenes and triphenylphosphine

Article abstract of DOI:10.1016/S0040-4020(01)88729-9

The simple and direct synthesis in good yields of substituted pyrazoles and 4-triphenylphosphoranylidene-4,5-dihydropyrazol-5-ones is reported.These products have been prepared by heterocyclization under different reaction conditions of some 1,5-zwitterio