On the photochemistry of 4-azidoquinoline 1-oxide: Structural elucidation of primary photoproduct

The primary product of the photolysis of 4-azidoquinoline 1-oxide (1) is believed to be the azo-dimer (4), consistent with the photochemistry of the pyridine analogue (2). This species has not been unambiguously identified, and previous workers have only isolated various isomers of the azoxy species (5). A combined IR, NMR, LC/MS and computational study confirms the structure 4 as the primary product of photolysis of 1 at 355 nm, suggesting that 5 arises from secondary photochemistry of 4.