Synfacts 2008(7): 0695-0695  
DOI: 10.1055/s-2008-1078470
Synthesis of Heterocycles
© Georg Thieme Verlag Stuttgart · New York

Substituted 1H-Pyrazoles and Isoxazoles from Cyclopropyl Oximes

Contributor(s): Victor Snieckus, Jignesh J. Patel
K. Wang, D. Xiang, J. Liu, W. Pan, D. Dong*
Northeast Normal University, Changchun and Changchun Institute of Applied Chemistry, P. R. of China
Further Information

Publication History

Publication Date:
20 June 2008 (online)

Significance

Reported here is a synthesis of substituted 1H-pyrazoles and isoxazoles from the oximes of 1-acyl and 1-carbamyl cyclopropanes under mild reaction conditions. The synthesis of the pyrazoles was achieved under Vilsmeier conditions (DMF/POCl3) via ring opening and chloro­vinylation followed by intramolecular cyclization. When DMF was replaced with CH2Cl2, the same substrates afforded isoxazoles via ring opening followed by an intramolecular vinylic substitution reaction. In some cases, the yields for 1H-pyrazoles were very low and the reactions furnished inseparable and uncharacterizable mixtures.