1,6-Diazaphenanthrenes from 1,2-Dihydro-4,6-dimethyl-2-(2-nitrophenyl)-pyridine-3,5-dicarboxylic Acid Esters

Article abstract of DOI:10.1002/ardp.19883210810

Reduction of the nitropyridines 7, obtained from the 1,2-dihydropyridines 4, yields the cyclic hydroxamic acids 8a, b.The nitrosopyridines 5, existing in the solid state as dimers 6, which are formed by irradiation of 4, cyclize with HCl to give the 9-chloro-substituted 1,6-diazaphenanthrenes 8c, d.The hydroxamic acids 8 could be desoxygenated with PCl3 to yield the lactames 9.