Photochemical dehydrogenation of 3,4-dihydro-2-pyridones

Photochemical dehydrogenation of various substituted 3,4-dihydro-2-pyridones was achieved in a very efficient way by employing 10–15 mol% of photo-induced electron transfer sensitizers like 9-cyanoanthracene, 9-cyanophenanthrene and 1-cyanonaphthalene in presence of molecular oxygen, for the first time.