Synthesis of pyrazolo[1,5-a]quinoxalin-4(5H)-ones via one-pot amidation/N-arylation reactions under transition metal-free conditions.

An efficient one-pot transition metal-free procedure for the synthesis of new pyrazolo[1,5-a]quinoxalin-4(5H)-ones from easily prepared 1-(2-chlorophenyl-5-ethylcarboxylate)pyrazoles and various primary alkylamines is described. The key steps involved in the synthesis of the new 5,6-fused ring system are the formation of an amide intermediate followed by an intramolecular N-arylation reaction via nucleophilic aromatic substitution.