title: Fluorinated heterocyclic compounds. An effective strategy for the synthesis of fluorinated Z-oximes of 3-perfluoroalkyl-6-phenyl-2h-1,2,4-triazin-5-ones via a ring-enlargement reaction of 3-benzoyl-5-perfluoroalkyl-1,2,4-oxadiazoles and hydrazine.
abstract: The reaction of 3-benzoyl-5-perfluoroalkyl-1,2,4-oxadiazoles with hydrazine has been investigated, evidencing the possibility of competitive reaction paths. Nucleophilic addition of the hydrazine to the electrophilic C(5) of the 1,2,4-oxadiazole ring, followed by ring opening and ring closure with enlargement, leads with high yield and in very mild experimental conditions to the formation of Z-oximes of 3-perfluoroalkyl-6-phenyl-2H-1,2,4-triazin-5-ones (11a-c) as major products of the reaction. In turn, the hydrazine can attack the electrophilic carbonyl carbon giving 4-perfluoroacylamino-5-phenyl-2H-1,2,3-triazoles (13a-c) through the well-known Boulton-Katritzky rearrangement of the intermediate hydrazones.
authors.affiliation: Dipartimento di Chimica Organica E. Paterno, Università degli Studi di Palermo, Viale delle Scienze-Parco d'Orleans II, I-90128 Palermo, Italy. sbuscemi@unipa.it
authors.forename: Silvestre
authors.initials: S
authors.lastname: Buscemi
authors.forename: Andrea
authors.initials: A
authors.lastname: Pace
authors.forename: Antonio
authors.initials: A
authors.lastname: Palumbo Piccionello
authors.forename: Gabriella
authors.initials: G
authors.lastname: Macaluso
authors.forename: Nicolo
authors.initials: N
authors.lastname: Vivona
authors.forename: Domenico
authors.initials: D
authors.lastname: Spinelli
authors.forename: Gianluca
authors.initials: G
authors.lastname: Giorgi