KOH-mediated intramolecular amidation and sulfenylation: A direct approach to access 3-(arylthio)imidazo[1,2-a]pyridin-2-ols
A simple and facile method for the synthesis of 3-(arylthio)imidazo[1,2-a]pyridin-2-ols has been developed by a KOH-mediated reaction of 2-aminopyridinium bromides with aryl thiols. The method afforded a wide range of 3-(arylthio)imidazo[1,2-a]pyridin-2-ols in moderate to excellent (56–95%) yields with excellent functional group tolerance. Synthetic utility of the protocol was demonstrated by gram-scale reaction and preparation of 2-aryl-3-(p-tolylthio)imidazo[1,2-a]pyridines from 3-(p-tolylthio)imidazo[1,2-a]pyridin-2-ol.
Metal-free synthesis of pyridin-2-yl ureas from 2-aminopyridinium salts
An unprecedented base promoted domino approach has been developed for the synthesis of pyridin-2-yl urea derivatives via the reaction of 2-aminopyridinium salts and arylamines. The developed strategy tolerated a wide range of functional groups and afforded pyridin-2-yl ureas in moderate to good yields. The reaction was postulated to involve tandem cyclization, intermolecular nucleophilic addition, ring opening, and demethylation.
Saroj,Patel, Om P.S.,Rangan, Krishnan,Kumar, Anil
(2019/07/23)
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