Transformations of the sulfur analogs of ?-carbolins under the influence of nucleophiles

Effect of the trifluoroacetyl group on the direction of the recyclization of the pyrazine ring in 6-trifluoroacetylpyrrolo[1,2-a]pyrazinium salts

“…Stupnikova et al [4] have described the formation of a base anhydride from N-methyl- [2,3-c]pyridinium iodide by the action of methanolic methylamine, which does not undergo the Kost-Sagitullin rearrangement upon heating at 100°C for 10 h.…”

“…The cyclotransformation of pyrrolo[1,2-a]pyrazinium salts 1a,b,d-g to give 6-acyl-2-methylpyrrolo-[1,2-a]pyrazin-1-ones 3a,b,d-g proceeds as the exchange of two atoms C (1) -C (2) in the ring by exocyclic atoms C (3) -C (4) .…”