Formation of isoxazole derivatives via nitrile oxide using ammonium cerium nitrate (CAN): a novel one-pot synthesis of 3-acetyl- and 3-benzoylisoxazole derivatives
作者:Ken-ichi Itoh、C.Akira Horiuchi
DOI:10.1016/j.tet.2003.11.088
日期:2004.2
4-diacetyl-1,2,5-oxadiazole 2-oxide) as the dimer of nitrile oxide. Moreover, it was found that yields of isoxazole derivatives were improved using ammonium cerium(III) nitrate tetrahydrate ((NH4)2Ce(NO3)5·4H2O, CAN(III))-formic acid. The reaction mechanisms based on nitration and formation of nitrile oxide mediated by CAN(IV) or CAN(III) from acetone or acetophenone are also proposed.
by the reaction of alkenes or alkynes with ketones (acetone or acetophenone), as both a reagent and the solvent, by three methods: iron(lll) nitrate under reflux, iron(III) salt-nitrogen dioxide (NO;) at room temperature, and iron(III) nitrate under microwave irradiation (MW).
Three types of reactions between nitrile oxides and (I) endo and exo alkenes, (II) dimerized alkenes, and (III) single alkenes, in which all the alkenes were generated in situ by NaHSO4/SiO2 are presented. This procedure allowed the concomitant generation of both nitrile oxides and alkenes in a single reaction vessel, gave higher yields for the expected isoxazoline products than the conventional method