Synthesis of 3,5-disubstituted 4-aminoisoxazoles by cyclization of O-(β-oxoalkyl)-substituted α-hydroxyimino nitriles
作者:V. P. Kislyi、E. B. Danilova、V. V. Semenov
DOI:10.1007/s11172-005-0379-0
日期:2005.5
4-Amino-5-benzoyl(acetyl)isoxazole-3-carboxamides were prepared by cyclization of α-hydroxyimino nitriles O-alkylated with bromoacetophenones (bromoacetone). The purity of the target 4-aminoisoxazoles can be substantially increased by treating O-alkylated oximes with LiClO4 before cyclization.
Competitive formation of 4-aminoisoxazoles and 5-aminooxazoles in the cyclization reactions of O-alkylated hydroxyimino nitriles
作者:V. P. Kislyi、E. B. Danilova、V. V. Semenov、A. A. Yakovenko、F. M. Dolgushin
DOI:10.1007/s11172-006-0495-5
日期:2006.10
Base-catalyzed cyclization of O-alkylated α-hydroxyimino nitriles gave mixtures of 4-aminoisoxazoles and 5-aminooxazoles, their ratio depending on the substituent structures and the reaction conditions. The formation mechanism of 5-aminooxazoles in this reaction is discussed.