Conjugated azoalkenes. Part XI. Direct synthesis of substituted pyrazoles and 4-triphenylphosphoranylidene-4, 5-dihydropyrazol-5-ones by heterocyclization of some …
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- zwitterionic species obtained from the 1, 4-conjugate addition of triphenylphosphine to the azo-ene system of conjugated azoalkenes.
