Application of organolithium and related reagents in synthesis. Part 18. Synthetic strategies based on aromatic metallation. A conversion of methyl ortho-pyridoylbenzoates into aza-anthra-5,10-quinones

Article abstract of DOI:10.1016/0040-4020(96)00620-5

The synthesis of the aza-anthraquinones (16) and (17) via metallation (LDA/THF) of the pyridine nucleus at the C³-carbon atom of the methyl ortho-pyridinecarbonyl benzoates (12) and (13), and then the intramolecular cross addition of the generated lithiated species to the carbomethoxy group is described.