Photoreactions of Compounds containing

Few if any novel photoreactions have been reported in nitrogen-containing systems during the period covered by this report. Publications have in most cases dealt with extensions to known processes, defining more clearly the scope and mechanism of these reactions. 

Rearrangements.- E-Photoisomerization occurs readily in imines and in azo compounds. The syn-isomer (1), for example, is the major product of irradiation of nitrofurazone (2) in solution and is formed together with the corresponding azine on exposure to laboratory illumination. The photoisomerization of azobenzene derivatives in solution, in membranes, in host-guest complexes of cyclodextrins, and in polymers continues to attract attention. The reversibility of E-photoisomerization of azobenzene in cyclo-hexane solution has been established, and the E/ -ratios generated by irradiation of various azobenzene derivatives adsorbed on 

Langmuir-Blodgett film, exhibits photochromic behaviour. 

Photochemically inducedelectrocyclic ring opening has also been reported for the 1,2-dihydro-1,2-pyridazine (8) which 

A recent review of the photochemistry of enamides draws attention to the ease with which enamides undergo 1,3-acyl shift on absorption of light, whereas dienamides prefer to follow a biT-photocyclization pathway. N-Aroylcarbazoles are converted on 

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Organic Aspects of Photochemistry Photoreactions of Compounds Containing Heteroatoms Other Than Oxygen , A. Gilbert, in Photochemistry , ed. D. Bryce-Smith, Royal Society of Chemistry, London, 1970, vol. 1, pp. 351-391. 

Photoreactions of Compounds containing Heteroatoms other than Oxygen... 

IIH6 Photoreactions of Compounds containing Heteroatoms other than Oxygen (CH2) tCH,),... 

Ill 16 Photoreactions of Compounds containing lieteroatoms other than Oxygen 391... 

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