-(10-DIAZO-10H-ANTHRACEN-9-YLIDENE)MALONODINITRILE - A CONVENIENT PRECURSOR OF 9,10-DISUBSTITUTED ANTHRACENES

The acid promoted decomposition of (10-diazo-10H-anthracen-9-ylidene)- malonodinitrile in the presence of water, methanol, ethanol, acetic an d propionic acid, ethyl thioglycolate, p-thiocresole, and acetyl aceto ne yielding 9,10-disubstituted 9,10-dihydroanthracenes was investigate d. Treatment of the reaction products with tri-ethyl amine followed by hydrochloric acid caused their tautomerization to the corresponding 9 ,10-disubstituted anthracenes. A mechanism for this:reaction is propos ed. The first example of an intermolecular C-C-bond formation during t he protic acid promoted decomposition of a diazo compound in the prese nce of CH-acids was found. An improved procedure for the preparation o f the starting diazo compound, which may serve as a convenient precurs or of 9,10-disubstituted anthracenes, is described.