Synthesis of cyanodibenzo[1,4]dioxines and their derivatives by cyano-activated fluoro displacement reactions

A new group of cyanodibenzo[1,4]dioxines have been synthesized by cyano-act ivated fluoro displacement reactions between cyanodifluorobenzenes and cate chols in DMF at 130 degreesC in the presence of potassium carbonate. This r oute is exemplified by the synthesis of cyanodibenzo[1,4]dioxines from seve ral substituted catechols. The reactions are virtually quantitative. Cyanod ibenzo[1,4]dioxines were hydrolysed with potassium hydroxide in ethylene gl ycol or converted into amide derivatives to yield additional substituted di benzo[1,4]dioxines. Cyanodibenzo[1,4]-dioxines are fluorescent and excitati on and emission data are presented. Improved syntheses of 4,5-diphenyl- ver atrole and 3,6-dimethylcatechol, the latter involving reduction of a phenol ic Mannich base at atmospheric pressure, have been elaborated.