When 2, 5, 8 (1H)-quinolinetriones were supported on silica gel and treated with 1- dimethylamino-1-azadienes in excess, followed by rapid chromatography, the corresponding 5, 8-dihydro-1, 8-diazaanthracene-2, 9, 10-triones or 1, 8-diazaanthracene-2, 9, 10-triones were obtained, normally in excellent yields. This procedure minimizes or completely prevents the addition of dimethylamine to the starting quinone, a problem that ...