The Curtius Rearrangement of Azidocarbonylfuroxans: Some Peculiarities and the Synthesis of Aminofuroxans

The kinetics of the Curtius rearrangement of the isomeric 3(4)-azidocarbonyl-4(3)-methylfuroxans has been studied; CON₃ group rearrangement was shown to proceed faster at the 3- versus the 4-position and to be favoured by an electron-withdrawing substituent at the second ring carbon atom; a series of previously inaccessible isomeric aminofuroxans has been synthesized.