Studies on the Syntheses of Heterocyclic Compounds. CCCVII. : A Synthesis of 3-Phenyl-1, 5-trimethylenepyrazole

Abstract

Claisen condensation of acetophenone with γ-butyrolactone in the presence of sodium ethoxide afforded 1-hydroxy-6-phenylhexane-4, 6-dione (III), which was treated with 80% hydrazine hydrate to give 3-phenyl-5-(3-hydroxypropyl)pyrazole (IV). Cyclization of IV with phosphoryl chloride or 48% hydrobromic acid gave 3-phenyl-1, 5-trimethylenepyrazole (II), one of the isomers of withasomnine.