THE PHOTOLYSIS OF 2,4,5,6-TETRACHLORO-1,3-DICYANOBENZENE

2,4,5,6-Tetrachloro-1,3-dicyanobenzene undergoes extensive transformation to many photoproducts of single and sequential excitation on UV irradiation in ethanol. Cl → H and CN → H exchange take place with the solvent, and solvent incorporation occurs followed by cyclization on the cyano groups(s) and/or further side-chain deoxygenation. Cl → Et exchange is also observed. The photoproducts were identified by gas chromatography—mass spectrometry (GC—MS). Some were isolated and analysed by IR and nuclear magnetic resonance (NMR) spectroscopy, which provided evidence for their structural identification. o-Cholorobenzonitrile was found to yield only the product of photoreduction of the C-Cl bond.