SU420627A1 - Method of producing derivatives of 2,2,5,5-tetra-substituted 3-imidazoline-1-oxyls - Google Patents

Description

one

This invention relates to a process for the preparation of new stable iminoxyl radicals in an imidazoline range.

A known method for producing, for example, 2,2,6,6 - tetramethyl-4 - oxopiperidin-1-oxyl by oxidation of the corresponding hydroxylamine.

The application of the known method for the oxidation of the corresponding hydroxylamines in the imidazoline range has resulted in the production of new stable iminoxyl radicals with more valuable properties than the known ones.

A process for the preparation of 2,2,5,5-tetra-substituted-3-imidazolin-1-oxyl derivatives of the general formula is described.

example, lead dioxide, air oxygen. The desired product is isolated in the known m method. You are 80-95%.

Example 1. A suspension of 0.65 g of 1-hydroxy-2,2,5,5-tetramethyl-4-phenyl-3-imidazoline (1a) and 7.00 g of lead dioxide in 50 ml of benzene are left under stirring for 3 hour at room temperature. The benzene solution is filtered and evaporated. The resulting 2,2,5,5-tetramethyl-4-phenyl-3-imidazolip-1-oxyl orange crystals (11a) have a yield of 0.61 g (94% of theory), and so on. 79.5-8H (hexane).

Found,%: C 72.3; H 7.9; N 13.1

C.sH.yNsO

Example 3. Oxidation of 1-okoi-5,5-dimethyl-2-spirocyclopentyl-4-phenyl-3-imidazoline (1c) under the conditions of example 1 results in 5,5-d "methyl-2-spiro" phenyl-3-imidazolin-1-oxyl (P-in) with a yield of 95%, and so on. pl. 64-65.6 ° (hexane).

Found,%: C 74.8; H 7.9; N 11.7.

ClsHigNsO

Calculated,%: C 74.1; H 7.9; N 11.5.

UV spectrum Hmax. nm (Ige): 250 (4.1).

Example 4. Oxidation of 1-hydroxy-2,2,4,5,5-pentamethyl-3-imidazoline (1 g) under the conditions of example 1 results in 2,2,4,5,5-tapemethyl-3-imidazoline -1-oxyl (11 g) in 80% yield. After chromatographic purification

T. KEP. 160-165 °.

Found,%: C 61.9; H 10.1; N 17.5. CgHisNaO

Calculated,%: C 62.0; H 9.8; N 18.1.

Example 5. By passing air through a suspension of 0.10 g of compound (1a) in benzene for one day at room temperature, an orange solution is formed, evaporating

In vacuum, which leads to a radical (Pv), the weight is 0.095 g (95% of the theoretical).

Subject invention

Claims (2)

1. A method for producing 2,2,5,5-tetra-substituted-3-imidazolin-1oxyl derivatives of the general formula ft N With N R7 Hi 6 where R is hydrogen, alkyl, aryl; Ri, R2 is alkyl, aryl, characterized in that the corresponding 1-hydroxy-2,2,5,5-tetra-substituted-3-imidazoline derivative is oxidized in an organic solvent medium, followed by isolation of the target product in a known manner. 2. A process according to claim 1, characterized in that lead oxide, air oxygen is used as the oxidizing agent.