title: Facile one-pot synthesis of [1, 2, 3]triazolo[1, 5-a]pyridines from 2-acylpyridines by copper(II)-catalyzed oxidative N-N bond formation.
abstract: An efficient and simple method for the synthesis of various [1, 2, 3]triazolo[1, 5-a]pyridines has been established. The method involves a copper(II)-catalyzed oxidative N-N bond formation that uses atmospheric oxygen as the terminal oxidant following hydrazonation in one pot. The use of ethyl acetate as the solvent dramatically promotes the oxidative N-N bond-formation reaction and enables the application of oxidative cyclization in the efficient one-pot reaction. A mechanism for the reaction was proposed on the basis of the results of a spectroscopic study.
authors.affiliation: Laboratory of Medicinal and Pharmaceutical Chemistry, Gifu Pharmaceutical University, 1-25-4, Daigaku-nishi, Gifu 501-1196 (Japan), Fax: (+81) 58-230-8112.
authors.forename: Tasuku
authors.initials: T
authors.lastname: Hirayama
authors.forename: Satoshi
authors.initials: S
authors.lastname: Ueda
authors.forename: Takahiro
authors.initials: T
authors.lastname: Okada
authors.forename: Norihiko
authors.initials: N
authors.lastname: Tsurue
authors.forename: Kensuke
authors.initials: K
authors.lastname: Okuda
authors.forename: Hideko
authors.initials: H
authors.lastname: Nagasawa
mesh_terms: D002384:Catalysis; D003300:Copper / Q000737:chemistry*; D003500:Cyclization; D015394:Molecular Structure; D010084:Oxidation-Reduction; D011725:Pyridines / Q000737:chemistry*
chemical_list: D011725:Pyridines; D003300:Copper
keywords: NN coupling; copper; cyclizations; hydrazones; nitrogen heterocycles