Wright State University

Bruce A Reinhardt

Frank W Harris

A method of preparing tetraketone precursors which are useful in the production of high temperature resistant polyquinoxaline resins. Suitable diketones are oxidized with a halogenating agent, such as cupric halide or hydrogen bromide, and dimethylsulfoxide to produce the corresponding tetraketone. The tetraketones which can be produced by the instant process have the formula: ##STR1## wherein R is hydrogen or an aryl, substituted aryl, heterocyclic or substituted heterocyclic radical and R' is an aryl, substituted aryl, arylalkyl, arylether, arylthioether, arylsulfoxide, arylsulfone, heterocyclic or substituted heterocyclic radical.

Preparation of tetraketones

A method for preparing diketone starting materials useful in synthesizing tetraketone precursors for high temperature resistant polyquinoxaline resins. Dicarboxylic acid derivatives that contain no alpha hydrogens are contacted in the presence of a strong base with an active-hydrogen compound of the type R -- CH.sub.2 -- X where R is an aryl, substituted aryl, heterocyclic or substituted heterocyclic radical and X is a nitrile group or a carboxylic acid functional group. A reaction intermediate is formed having the formula: ##STR1## wherein R and X are as defined in regard to the active-hydrogen compound and R' is the same as R. The reaction intermediate is hydrolyzed and decarboxylated to form the diketone. The diketones produced by the instant invention have the formula: ##STR2## where R and R' are the same as in the reaction intermediate.

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Dayton, OH, United States of America

Bruce A Reinhardt