New highlights of the syntheses of pyrrolo[1,2-a]quinoxalin-4-ones

• Emilian Georgescu,
• Alina Nicolescu,
• Florentina Georgescu,
• Florina Teodorescu,
• Daniela Marinescu,
• Ana-Maria Macsim and
• Calin Deleanu

Beilstein J. Org. Chem. 2014, 10, 2377–2387, doi:10.3762/bjoc.10.248

• . Keywords: 1,3-dipolar cycloadditions; multicomponent; one-pot three-component reactions; pyrrolo[1,2-a]benzimidazole; pyrrolo[1,2-a]quinoxalin-4-one; Introduction The pyrrolo[1,2-a]quinoxaline system has significant biological activities and is a subject fo constant interest. This skeleton is a

• quinoxalines [6] have been recently reviewed. Among other synthetic routes, the 1,3-dipolar cycloaddition of heterocyclic N-ylides with various activated alkynes or alkenes is an important method for constructing fused heterocyclic systems such as pyrrolo[1,2-a]quinoxaline and pyrrolo[1,2-a]benzimidazole [7][8

• -(methoxycarbonylmethyl)benzimidazolium bromides with dimethyl acetylenedicarboxylate (DMAD) in presence of K2CO3 in DMF [7] or in presence of triethylamine in acetonitrile [8] give a mixture of pyrrolo[1,2-a]benzimidazole (2–7%) and a compound whose formation involves the loss of an alcohol molecule for which different