Synthesis and analysis of benzisoxazoles as substrates for the Kemp elimination in presence of hemoproteins

This elaborate focuses on the synthesis and kinetic analysis of substituted benzisoxazoles as substrates for the Kemp reaction, in presence of three hemoproteins, i.e. cytochrome c, myoglobin and hemoglobin. Formylation of a phenol derivative, nucleophilic addition of hydroxylamine and a final ciclization are the three step keys which afforded the desired fused isoxazole rings. The base-catalyzed decomposition of synthesized substrates was monitored through UV/Vis spectrophotometry, in order to study the catalytic effect of different enzymes under examination, using a common spectrophotometer UV/Vis. Finally the kinetic isotope effect of a deuterated substrate was analyzed to evidence the nature of the rate-limiting step of Kemp elimination.