Synthesis of diazafluorene- and diazafluorenone-N,N′-dioxides using HOF·CH3CN

A variety of diazafluorenes and diazafluorenones were oxidized using the HOF·CH₃CN complex to form the corresponding N,N′-dioxide derivatives under mild conditions. The products exhibit red-shift absorptions in the UV/visible spectrum relative to the parent compounds. Many such oxidations could not be achieved with any other oxygen-transfer agent.