Synthesis 2005(17): 2901-2905  
DOI: 10.1055/s-2005-916008
PAPER
© Georg Thieme Verlag Stuttgart · New York

Stereoselective Synthesis of 3,5-Dialkyl-3,5-dihydro-3,5-diphenyl-4H-pyrazol-4-ones

Andrey G. Moiseev, Douglas C. Neckers*
Center for Photochemical Sciences, Bowling Green State University, Bowling Green, OH 43403, USA
Fax: +1(419)3720366; e-Mail: neckers@photo.bgsu.edu;
Further Information

Publication History

Received 12 April 2005
Publication Date:
26 August 2005 (online)

Abstract

We report stereoselective five-step syntheses of cis-3-ethyl-3,5-dihydro-3,5-diphenyl-5-methyl-4H-pyrazol-4-one (cis-1b) and trans-3,5-diethyl-3,5-dihydro-3,5-diphenyl-4H-pyrazol-4-one (trans-1c). The key synthon was 1,3-diphenylpent-2-en-1-one (5b) synthesized in a new one-pot crossed aldol/dehydration reaction of acetophenone with propiophenone using titanium(IV) chloride/tributylamine, followed by treatment with methanesulfonyl chloride and triethylamine.