Irradiation of dihydropyridone 1 a in water yields mainly the unsaturated amides 3 (73%), 4 (8%), and acetone. A 1.3% yield of photohydration product 5 a is also obtained. Irradiation of 1 a in anhydrous methanol yields carbinolamidoether 8 (57%), whereas in t-butyl alcohol enamide 7 is the reaction product. Irradiation of the N-methyl derivative of 1 a (1 b) yields 90% of starting material and 5% of a photohydrate 5 b. The mechanistic path of the ...
