Nitron derivative, 8-hydroxy-1,4,5,7-tetramethyl-6,8-diazabicyclo [3.2.1]oct-6-ene 6-oxide, was obtained by the cyclodimerization of 3-methyl-3-buten-2-one oxime at 80 °C. This nitron was easily converted into the stable nitroxy radical by the attack of poly(N-methylacrylamide) radical.