A Facile General Synthesis of Arylmaleic Anhydrides:, Ccl.net archives
By a sequence involving Knoevenagel condensation, Michael addition of cyanide, hydrolysis, and selenium dioxide oxidation, a series of seven aryl maleic anhydrides were prepared in excellent overall yields. The regiospecificity of reaction of these anhydrides with various nucleophilic species, e.g. Me3SiN3, NH3, and PhNH2 was investigated. Except for a few cases, the nucleophile attacks the more hindered carbonyl, in a reaction controlled by electronic rather than steric factors. These anhydrides are of particular utility in the synthesis of 4-and 5-Aryl Substituted 1,3(3H) Oxazine-2,6-Diones (Oxauracils).