1: With sodium hypochlorite; sodium chlorite; 2,2,6,6-tetramethyl-1-piperidinyloxy, free radical in water; acetonitrile T=35°C; pH=6.7; 7 h; Inert atmosphereaq. phosphate buffer; 2: With sodium hydrogencarbonate; sodium sulfite in water; acetonitrile T=0°C; pH=8; Inert atmosphere; 3: With hydrogenchloride in water pH=2; Inert atmosphere;