312700-70-2Relevant academic research and scientific papers
Substituent effects in isoxazoles: Identification of 4-substituted isoxazoles as Michael acceptors
Lee, Connie K.Y.,Easton, Christopher J.,Gebara-Coghlan, Mariana,Radom, Leo,Scott, Anthony P.,Simpson, Gregory W.,Willis, Anthony C.
, p. 2031 - 2038 (2007/10/03)
Crystallographic and theoretical studies have been used to investigate substituent effects, which are manifest in electrochemical and yeast-catalysed reactions of 4- and 5-acyl-, alkoxycarbonyl-, cyano- and phenyl-substituted isoxazoles. The results show that isoxazoles substituted at the 4-position with π-electron-withdrawing substituents have enhanced C4-C5 bond polarity and are structurally similar to Michael acceptors. As a consequence there is elongation and weakening of their N-O bonds. By contrast, their 5-substituted regioisomers and isoxazoles substituted at C4 with conjugating, but not π-electron-withdrawing, substituents have diminished C4-C5 bond polarity. This results in the selective electrochemical and yeast-catalysed reduction of 4-substituted isoxazoles, as well as their hydrogenolytic ring cleavage and conjugate reduction with sodium borohydride.
