Preparative uses of aryldiazonium salts of complex fluoro-acids. Part II. Novel preparations of fluorenones and xanthones from aryldiazonium tetrafluoroborates

Abstract

A novel and often convenient preparation of fluorenones and xanthones, the latter in some cases accompanied by 6H-dibenzo[b,d]pyran-6-ones, has been devised by decomposing o-carboxybenzenediazonium tetrafluoroborates in aromatic hydrocarbons or phenols respectively. Xanthones have also been prepared by thermolysis of aryldiazonium tetrafluoroborates in salicyclic acid. The mechanism and scope of these reactions are discussed.