Stereospecific Alkylation of 3,5,5-Trisubstituted-4-hydroxy-1-p-tosyl-2-pyrazolines by Trimethylaluminum. An Efficient Synthesis of 3,3,5,5-Tetrasubstituted-1-pyrazolin-4-ones

Article abstract of DOI:10.1021/jo01305a007

Isomeric p-tosylpyrazolines 5 and 6 are obtained in high yield by cyclization of the tosylhydrazones of various β,β-disubstituted-α,β-epoxy ketones 4.Oxidation of these mixtures to pyrazolones 9 followed by selective reduction affords isomers 5.Reaction o