THE SYNTHESIS OF WATER-SOLUBLE ISOINDOLINE NITROXIDES AND A PRONITROXIDE HYDROXYLAMINE HYDROCHLORIDE UV-VIS PROBE FOR FREE-RADICALS

The novel water soluble nitroxides thylammonio-1,1,3,3-tetramethylisoi ndolin-2-yloxyl iodide 8 and 5-carboxy-1,1,3,3-tetramethylisoindolin-2 -yloxyl 10 are prepared by nitration of the parent nitroxide 2 and bro mination of its amine precursor 1; the stable (t(1/2) > 580 h in MeOH; ca 72 h in physiological saline) pronitroxide 2-hydroxy-1,1,3,3-tetra methylisoindoline hydrochloride 6 was synthesised by treatment of 2 wi th HCl gas in dry EtOH and reacts with radicals to form 2; the transfo rmation can be followed by UV-VIS spectroscopy.