Recyclization of pyrrolo[1,2-a]pyrazinium salts into 6- and 8-aminoindolizines

Recyclization of 3-alkylpyrrolo1,2-a]pyrazinium salts in the presence of base afforded derivatives of 6-aminoindolizine. Rearrangement of 1,3-dialkylpyrrolo1,2-a]pyrazinium salts proceeded in two directions, giving rise to both 6- and 8-aminoindolizines, though the latter predominated in terms of yield. In the absence of alkyl substituents at positions 1 and 3 the pyrazine ring was cleaved on treatment with base, yielding derivatives of 2-acylpyrrole.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 921–928, July, 1992.