Synthesis and reactivity of pyrrolo[1,2-α]quinoxalines. Crystal structure and AM1 calculation

2-Methylquinoxaline reacts with ethyl bromopyruvate giving 2-substituted pyrrolo[1,2-α]quinoxalines. The yield of the condensation depends on the functionalization of starting materials, and optimization is obtained with 2-dimethylamino-3-methylquinoxaline ( 1c ). Reactivity of the resulting pyrrolo[1,2-a]-quinoxalines was investigated and supported by a theoretical approach (AM1 calculation performed with the MOPAC 6.0 software). X-ray analysis of 5 which crystallizes in the monoclinic system, space group P2₁/n, with a = 9.095(1), b = 8.972(1), c = 17.749(3) A, β = 96.56(1)°, is also reported.