title: 4-Pyridylnitrene and 2-pyrazinylcarbene.
abstract: Both flash vacuum thermolysis (FVT) and matrix photolysis generate 2-diazomethylpyrazine (22) from 1,2,3-triazolo[1,5-a]pyrazine (24). FVT of 4-azidopyridine (18) as well as of 24 or 2-(5-tetrazolyl)pyrazine (23) affords the products expected from the nitrene, i.e., 4,4'-azopyridine and 2- and 3-cyanopyrroles. Matrix photolyses of both 18 and 24 result in ring expansion of 4-pyridylnitrene/2-pyrazinylcarbene to 1,5-diazacyclohepta-1,2,4,6-tetraene (20). Further photolysis causes ring opening to the ketenimine 27.
authors.affiliation: School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Qld 4072, Australia.
authors.forename: Curt
authors.initials: C
authors.lastname: Wentrup
authors.forename: Ales
authors.initials: A
authors.lastname: Reisinger
authors.forename: David
authors.initials: D
authors.lastname: Kvaskoff
keywords: carbene–nitrene interconversion; diazepines; flash vacuum thermolysis; matrix photochemistry; nitrile ylides; reactive intermediates