title: Pyrrolodiazines. 2. Structure and Chemistry of Pyrrolo[1,2-a]pyrazine and 1,3-Dipolar Cycloaddition of Its Azomethine Ylides.
abstract: A new synthesis of the pyrrolo[1,2-a]pyrazine system from pyrrole is described. In light of the ab initio calculations carried out on this heterocyclic system some of its basic chemistry was investigated and included electrophilic substitution, addition of organolithium reagents, metalation with lithium diisopropylamide and subsequent reaction with electrophiles, and formation of salts by quaternization of the nonbridgehead nitrogen. N-ylides obtained from these salts undergo 1,3-dipolar cycloaddition with suitable dipolarophiles to give dipyrrolo[1,2-a]pyrazines, pyrazolo[1,5-a]-pyrrolo[2,1-c]pyrazines, and heterobetaines. Examples of intramolecular 1,3-dipolar cycloadditions are also reported.
authors.affiliation: Institut de Quimica Computacional, Universitat de Girona, C/Albareda, 3-5, 17071-Girona, Spain.
authors.forename: José M.
authors.initials: JM
authors.lastname: Mínguez
authors.forename: María I.
authors.initials: MI
authors.lastname: Castellote
authors.forename: Juan J.
authors.initials: JJ
authors.lastname: Vaquero
authors.forename: José L.
authors.initials: JL
authors.lastname: García-Navio
authors.forename: Julio
authors.initials: J
authors.lastname: Alvarez-Builla
authors.forename: Obis
authors.initials: O
authors.lastname: Castaño
authors.forename: José L.
authors.initials: JL
authors.lastname: Andrés