Efficient one-pot synthesis of functionalised imidazo[1,2-a]pyridines and unexpected synthesis of novel tetracyclic derivatives by nucleophilic aromatic substitution?

RSC Advances Pub Date: 2020-02-25 DOI: 10.1039/C9RA10447J

Abstract

Novel tetracyclic imidazo[1,2-a]pyridine derivatives have been prepared by intramolecular nucleophilic aromatic substitution of 5-fluoroimidazo[1,2-a]pyridines under basic conditions. Use of the non-nucleophilic alcoholic solvent tert-butanol, rather than methanol, increased the yield of the tetracycles by reducing the competing intermolecular reaction observed for methanol. In addition, a modified protocol for the dehydration of formamides to isocyanides has been found to be tolerant of an unprotected hydroxyl functional group and one-pot conversion to imidazo[1,2-a]pyridyl-aminocyclohexanol analogues is reported.

Graphical abstract: Efficient one-pot synthesis of functionalised imidazo[1,2-a]pyridines and unexpected synthesis of novel tetracyclic derivatives by nucleophilic aromatic substitution
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