Rate-Equilibrium Relationships for the Deprotonation of ... Contribution from the Department of Chemistry, University of Toronto, Toronto, Ontario M5S 1 AI, Canada. Received October 12, I989 ... Abstract: Substituent effects upon the equilibria and kinetics of enolate ion formation from eight 4-(X-phenacyl)pyridines (5), eight l-methyl-4-(X-phenacyl)pyridinium cations (6), five l-benzyl-4-(X-phenacyl)pyridinium cations (7), and eight 1 -(X-benzyl)-4- ...