Combinatorial synthesis of 4-oxo-4H-imidazo[1,5-a]quinoxalines and 4-oxo-4H-pyrazolo[1,5-a]quinoxalines

摘要

A combinatorial synthetic route yielding imidazo[1,5-a]quinoxalines and pyrazolo[1,5-a]quinoxalines is described.The use of 2-fluoroaniline and 1H-imidazole-4-carboxylic acid,respectively,1H-pyrazole-3-carboxylic acid in the Ugi-reaction(U-4CR)followed by a nucleophilic aromatic substitution(S_NAr)affords the imidazo-as well as the pyrazolo-[1,5-a]quinoxaline moiety in good yield and high diversity.