Synthesis of 5-Hydroxy- and 5-Amino-1-tosyl-5-phenyl-3-(2-arylvinyl)4,5-dihydropyrazoles

The reaction of (beta)-arylacryloyloxiranes with tosylhydrazine leads to unexpected 5-hydroxysubstituted ((DELTA))^2-pyrazolines. A series of 3-styryl substituted pyrazoles and 5-amino-((DELTA))^2-pyrazolines were synthesized from the 5-hydroxy-((DELTA))^2-pyrazolines. The mechanism of this process has been proposed based on current and previous results.