272458-08-9Relevant academic research and scientific papers
Heterocyclic free radicals. Part 1. 4,5-Diazafluorene derivatives of Koelsch's free radical: an EPR and metal-ion complexation study
Plater, M. John,Kemp, Steven,Lattmann, Eric
, p. 971 - 980 (2007/10/03)
Heteroaromatic precursors to nitrogen substituted derivatives of Koelsch's free radicals have been prepared by the condensation of 4,5-diazafluorene with a fluorenylidene or diazafluorenylidene. These compounds appear coloured and can exist in different tautomeric forms. An improved one pot synthesis of 4,5-diazafluorenone has been developed by the oxidative ring contraction of 1,10-phenanthroline with aqueous potassium permanganate. Aza derivatives of Koelsch's free radical are easily generated by oxidation of the appropriate precursors with K3Fe(CN)6. Treatment of 9-[(9H-4,5-diazafluoren-9-ylidene)phenylmethyl]-9H-fluoren-9-yl radical with CuCl2 in EtOH gives a brown precipitate of a 1:1 radical-ligand complex.
