Oxidative cyclization of 1-(pyridin-2-yl)guanidine derivatives: a synthesis of [1,2,4]triazolo[1,5-a]pyridin-2-amines and an unexpected synthesis of [1,2,4]triazolo[4,3-a]pyridin-3-amines

Autor:	Toshiaki Nagata, Kazuhisa Ishimoto, Tomomi Ikemoto, Mika Murabayashi
Rok vydání:	2015
Předmět:	Reaction mechanism Oxidative cyclization Aqueous solution Chemistry Nitrene Organic Chemistry Biochemistry Medicinal chemistry Potassium carbonate chemistry.chemical_compound Drug Discovery Diazirine Methanol Guanidine
Zdroj:	Tetrahedron. 71:407-418
ISSN:	0040-4020
DOI:	10.1016/j.tet.2014.12.015
Popis:	Oxidative cyclization of 1-(pyridin-2-yl)guanidine derivatives using N -chlorosuccinimide and aqueous potassium carbonate has been investigated. Chlorination of 1-(5-nitropyridin-2-yl)guanidine by N -chlorosuccinimide in methanol followed by addition of aqueous potassium carbonate gave rise to cyclization and afforded 6-nitro-[1,2,4]triazolo[1,5- a ]pyridin-2-amine in one-pot. In the course of studying the scope and limitation of the reaction, it was found that some of the examined 1-(pyridin-2-yl)guanidine derivatives gave not only the desired [1,2,4]triazolo[1,5- a ]pyridin-2-amines but also unexpected [1,2,4]triazolo[4,3- a ]pyridin-3-amine products. As plausible reaction mechanisms of this oxidative cyclization, diazirine formation and nitrene formation are presented.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_________::5aa1708fddbda053d98dc6e27d158966 https://doi.org/10.1016/j.tet.2014.12.015 Zobrazit plný text záznamu Full Text from ScienceDirect