Photochemical reactions of 1-oxo-2-diazo-1, 2-dihydronaphthalenes and reactivity of their products

Photochemical reactions of 4-tolyl 1-oxo-2-diazo-1,2-dihydronaphthalene-5-sulfonate (DNQ-5STL) are studied, as a typical example of six-membered ring α -diazoketones, together with its two prototype molecules, i.e., 1-oxo-2-diazo-1,2-dihydrobenzene (DBQ), 1-oxo-2-diazo-1,2-dihydronaphthalene (DNQ), by reverse-phase liquid chromatography. The obtained products under different reaction conditions, such as photochemical reactions of pure solid DNQ-5STL in air and in vacuo, are examined. The reactivity of the carboxy compounds produced in air or in a water-containing solution is also discussed. They exhibit decarboxylation, dimerization or azo formation in the presence of bases, being markedly dependent on the type of molecules. The azo formation rate constant of the 3-carboxyindene analogue from DNQ-5STL is much greater than that of its dimerization.