J. Einhorn et al., SYNTHESIS OF STABLE ALPHA,ALPHA'-BIS(CARBOXYMETHYL) SUBSTITUTED NITROXIDES VIA AN ORIGINAL DIANION-BASED STRATEGY, Journal of the Chemical Society, Chemical Communications, (10), 1995, pp. 1029-1030
New stable nitroxides, analogous to TEMPO (tetramethylpiperidine-N-oxy
l) where two alpha,alpha' methyl groups are formally replaced by ester
functions, are prepared via dienolate chemistry followed by a deprote
ction-oxidation sequence.