1,3-dihydroxy-2--4,4,5,5-tetramethyl-2-imidazoline

N-t-butyl N-nitroxide N'-oxide

ethyl N--D-(-)-α-phenylglycinate

2--4,4,5,5-tetramethyl-4,5-dihydroimidazol-3-oxid-1-oxyl

bis->-m-phenylenediamine