Fragmentations and Miscellaneous Reactions

The diene (109) is formed when the keto-diene (110) is irradiated in various solvents using A = 254 nm. The Diels-Alder activity of the diene (109) was 

Irradiation (A 220 nm) of the saturated esters (117, 118, and 119) and acids results in two photoprocesses. The ester (117) undergoes elimination of acetic 

Tsujimoto, Y. Kamiyama, Y. Furukawa, and M. Ohashi, Kokagaku Toronkai Koen Yoshishu, 

The photolysis of the ether (127) in n-heptane yields free radicals in a first-order reaction.The lactone (128) and the 3-tetrahydropyrone (129) are formed when the compound (130) is subjected to solution-phase irradiation.  

A study of a series of bis-sulphenylated keto compounds has revealed a remarkable solvent effect. Thus irradiation of, for example, (132) in acetonitrile yields (133, 43%) as the major product accompanied by two minor products (134, 25%) and (135, 23%). But in benzene the products (134, 63%) and (135,49%) were produced with no evidence for the formation of the cyclized material (133). Several examples of the reaction are cited. The photodegradation of some sulphonamides e.g., 136) has been studied. 

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