Multiple n?* Triplet Reactions in the Photochemistry of Alkyl-Substituted Acylpyrazines, Ketones with Four Low-Lying Zero-Order Triplets

Article abstract of DOI:10.1021/jo00103a045

Irradiation of 7a-c and 11a-c leads to triplet-state abstraction of hydrogen by both nitrogen and oxygen with formation of the products shown in Schemes 1 and 2.Stern-Volmer quenching studies yield indistinguishable k_qτ's for abstraction by carbonyl oxygen and adjacent nitrogen in 11a, and also for intermolecular comparisons both of abstraction by nitrogen in 11b and 11c, and also of abstraction by oxygen in 7a and nitrogen in 7b.Reactions of 7a and 11a are sensitized by acetone, but fragmentation of 7c is not.