Photochemical reactions of azo compounds. X. Photochemical properties of azobenzene-2-carboxylic acids

Abstract

Two chloro and two methyl derivatives of azobenzene-2-carboxylic acid have been found to yield the corresponding derivatives of benzo[c]cinnoline-4- carboxylic acid in good yields when irradiated in 98% sulphuric acid. The question of intramolecular hydrogen bonding in relation to the properties of azobenzene-2-carboxylic acids is discussed. Infrared absorption spectra of the neutral compounds have provided confirmation of internal hydrogen bonding. Attempts to prepare the cis isomers of these azo compounds have been unsuccessful.