A new nitroxide radical derived from 2,2,4,6,6-pentamethyl-1,2,5,6-tetrahydro-pyrimidine and its conversion to 2,2,4,6,6-pentamethyl-1,2,5,6-tetrahydro-pyrimidine-1-oxyl

The new oxaziridine nitroxide, 2,2,4,4,6-pentamethyl-7-oxa-1,3-diaza-bicyclo[4.1.0]heptan-3-oxyl, has been obtained in 90% yield by oxidation of 2,2,4,6,6-pentamethyl-1,2,5,6-tetrahydro-pyrimidine with MCPBA in ether. This nitroxide is stable in the solid state or in non-protic solvents. It was converted to the known 2,2,4,6,6-pentamethyl-1,2,5,6-tetrahydro-pyrimidine-1-oxyl by successive reduction with LiAlH4 and oxidation with Ag2O, with a reproducible yield of 16% from the starting tetrahydropyrimidine.