2,3-Dichloro-5,6-dicyano-1,4-benzoquinone(DDQ)/Tert-butyl nitrite(TBN)/O2-mediated tandem reaction for the synthesis of 1-aza-anthraquinones and pyridocoumarins

A tandem reaction of 2-aminonaphthoquinone/4-aminocoumarins with 1,3-diarylpropenes mediated by 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ)/tert-butyl nitrite (TBN)/O2 is disclosed. It involves oxidative coupling, intramolecular annulation and dehydro-aromatization reaction, which provides an efficient and mild method for the synthesis of 1-aza-anthraquinones and pyridocoumarins.