L-Hydroxy-2,2,4,5,5-pentamethyl-3-imidazoline

Pentamethyl-3-imidazoline-3-oxide-l-oxyl (7a). l-Hydroxy-2,2,4,5,5-pentamethyl-3-imidazoline-3-oxide (6a) (10 g, 58 mmoles) is rubbed with Mn02 (20 g, 230 mmoles) and intermixed in benzene (200 ml) until the solution acquires an intensive yellow color (for about 30 min). The solution is decanted, 150 ml of benzene is added to the residue, and the solution is intermixed again till it acquires an intensive yellow color (for about 30 min). Then the solution is decanted. This operation is repeated two or three more times until the coloring of the benzene solution ceases. The combined filtrates are evaporated under reduced pressure. The yellow oil that remains after the evaporation of the benzene is crystallized. The yield of 7a is 9 g (90%), m.p. 103-104°C (from hexane-benzene mixture, 1 1). UV (ethanol), Anm (Ig e) 234 (4.07). IR (in KBr), vem- 1601 (C=N), 1294 (N+—O ), 1250, 1170. 

Styryl-2,2,5,5 tetramethyl-3-imidazoline-3-oxide I-oxyl(42a). To a solution of sodium hydroxide (0.5 g, 12.5 mmoles) in methanol (10 ml) are added l-hydroxy-2,2,4,5,5-pentamethyl-3-imidazoline-3-oxide (6a) (2.0 g. 

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