Production of malonic anhydrides and derivatives thereof

A process for producing a derivative of a malonic anhydride selected from the group consisting of a malonic acid, a malonic acid monoester and a malonic acid monoamide, which comprises passing ozone through an inert organic solvent containing an enol-lactone dimer of a ketene, said dimer of a ketene having the general formula ##STR3## where R and R' are selected from the group consisting of hydrogen, alkyl having a chain length ranging from C.sub.1 to C.sub.20, cycloalkyl containing from about 3 to about 8 carbon atoms, carbocyclic aryl, said aryl groups containing from about 6 to about 20 carbon atoms, and where R and R' can be the same or different, and where R and R' together can constitute the atoms necessary to form a carbocyclic ring of from about 4 to about 8 carbon atoms, said solvent being maintained at a temperature ranging from about -100.degree. C. to about 0.degree. C., and forming a malonic anhydride having the formula ##STR4## where R and R' are defined as above, adding a derivatizing agent selected from the group consisting of water, alcohols, phenols, ammonia and amines to the reaction mixture, and permitting the reaction mixture to warm to about room temperature.