A Very Efficient Synthesis of (1H)-1,5-Diazaanthracene-2,9,10-triones

Acylation of ortho-lithiated species derived from N,O-dipivaloyl-6-amino-5,8-dimethoxy-4-methyl- 2(1H)-quinolinone, followed by condensation with carbonyl reagents and in situ N-deprotection gave 7-alkyl or 6,7-dialkyl-9,10-dimethoxy-4-methyl-1,5-diaza-2(1H)-anthracenones, which were finally oxidised to the title compounds.