Functionalized derivatives of sterically hindered o-quinones and pyrocatechols. 3,6-di-tert-butyl-4-dicyanometyl-1,2-benzoquinone and its isomers

Base-catalyzed interaction of 3,6-di-rert-butyl-1,2-benzoquinone with malononitrile mainly occurs as 1,4-addition to give 3,6-di-tert-butyl-4-dicyanomethylpyrocatechol. Its oxidation leads to 3,6-di-tert-butyl-4-dicyanomethyl-1,2-benzoquinone, which converts into 3,6-di-tert-butyl-2-hydroxy-alpha,alpha-dicyano- 1,4-quinomethane in solution and in the solid state. The latter rearranges into isomeric 3,6-di-tert-butyl-5-dicyanomethylenecyclohex-3-ene-1,2-dione. Reverse conversion occurs under the action of amines. Semiquinone complexes of dicyanomethylquinone were studied in solutions by ESK.