Tetrahedron

Synthesis of pyrazolidine, 1-pyrazoline, 2-pyrazoline derivatives by selenium-induced cyclization of homoallylhydrazines

M Ternon, F Outurquin, C Paulmier

Index: Ternon, Michael; Outurquin, Francis; Paulmier, Claude Tetrahedron, 2001 , vol. 57, # 52 p. 10259 - 10270

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Citation Number: 20

Abstract

The PhSeBr-induced cyclization of N′-but-3-en-1-yl ethoxycarbonylhydrazines 1, phenylhydrazines 2 and dimethylhydrazines 3 has been studied. A 5-exo-trig ring closure occurred in each case and phenylselanylmethyl-pyrazolidines 4, 2-pyrazolines 5 and 10, 1- pyrazolines 8 and pyrazolidinium bromides 11 were synthesized. Radical deselenenylation has allowed the preparation of 5-methylpyrazolidines 12 and 5-methyl-2-pyrazolines 13 ...