Gl. Rusinov et al., 2,3-Dichloro-1-alkylpyrazinium tetrafluoroborates: the synthesis and reactions with nucleophiles, MENDELEEV C, (2), 2001, pp. 78-80
The alkylation of 2,3-dichloropyrazine with the Meerwein reagents R3O+BF4-
(R = Me or Et) afforded 1-alkyl-2,3-dichloropyrazinium tetrafluoroborates,
which were transformed into mono- or disubstitution products, while the rea
ction of these salts with 1,4-N,X-dinucleophiles resulted in fused heterocy
clic systems.