University of Missouri

Megh Singh

Robert W Murray

The subject invention relates to a method of synthesizing nitroxides from secondary amines. This method uses a suitable dioxirane compound such as dimethyldioxirane (DMD), which is relatively stable and simple to synthesize, as the oxidizing agent. A quantity of a secondary amine having no hydrogen atoms directly attached to the alpha carbon atoms is mixed with a 2x molar ratio of the dioxirane. In a first reaction, the secondary amine is oxidized to form a hydroxylamine; in a second reaction, the hydroxylamine is further oxidized to form a nitroxide. When the dioxirane loses an oxygen atom it converts into a ketone; for example, dimethyldioxirane is converted into acetone. This is very convenient, since the ketone byproduct is a solvent that can be easily removed after the reaction without causing interfering reactions. This method provides a simple, highly selective, rapid reaction with very high yields. It can be carried out in a single reaction vessel and can be used with a wide variety of secondary amines (including secondary amines having more than one amine group) to create a corresponding variety of nitroxides.

Synthesis of nitroxides using dioxiranes

The subject invention relates to a method of synthesizing hydroxylamines from secondary amines. This method uses a dioxirane compound such as dimethyldioxirane (DMD, which is relatively stable and simple to synthesize), as the oxidizing agent. The reaction proceeds as follows: ##STR1## This method provides a simple, one-step reaction with high yields. It can be performed in acetone solution, and the transferral of an oxygen atom from dimethyldioxirane to the secondary amine converts the dioxirane into acetone, the solvent, permitting simple workup and purification. This method can be used with a wide variety of secondary amines, including aliphatic, aromatic, cyclic, and heterocyclic secondary amines, to create a corresponding variety of hydroxylamines.

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St. Louis, MO, United States of America

Megh Singh