title: 3-Pyridylnitrene, 2- and 4-pyrimidinylcarbenes, 3-quinolylnitrenes, and 4-quinazolinylcarbenes. Interconversion, ring expansion to diazacycloheptatetraenes, ring opening to nitrile ylides, and ring contraction to cyanopyrroles and cyanoindoles.
abstract: Precursors of 3-pyridylnitrene and 2- and 4-pyrimidinylcarbenes all afford mixtures of 2- and 3-cyanopyrroles on flash vacuum thermolysis, but 3-cyanopyrroles are the first-formed products. 3-Quinolylnitrenes and 4-quinazolinylcarbenes similarly afford 3-cyanoindoles. 2-Pyrimidinylcarbenes rearrange to 3-pyridylnitrenes, but 4-pyrimidinylcarbenes and 4-quinazolinylcarbenes do not necessarily rearrange to the corresponding 3-pyridylnitrenes or 3-quinolylnitrenes. The ring contraction reactions are interpreted in terms of ring opening of either the nitrenes or the diazacycloheptatetraenes to nitrile ylides.
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: Nguyen Mong
authors.initials: NM
authors.lastname: Lan
authors.forename: Adelheid
authors.initials: A
authors.lastname: Lukosch
authors.forename: Pawel
authors.initials: P
authors.lastname: Bednarek
authors.forename: David
authors.initials: D
authors.lastname: Kvaskoff
keywords: carbene-nitrene interconversion; diazepines; flash vacuum thermolysis; matrix photochemistry; nitrile ylides; reactive intermediates