Abstract Treatment of 2-X-substituted pyrazines [X= H, Me, Et, Pr, i-Pr, t-Bu, MeCH (OH), H 2 N, AcNH] with O-mesitylenesulfonylhydroxylamine gave the corresponding 2-X-and 3-X-(1- amino) pyrazin-1-ium mesitylenesulfonates. 2-Alkylpyrazines (X= Me, Et, Pr, i-Pr) displayed a correlation between the logarithms of the concentration ratio of 2-and 3-substituted cations and substituent steric constants. Wider series of substituted pyrazines [X= H, Me, Et, Pr, i- ...