Abstract: The reactions of N-(2-~ yanoethyl) isoquinolinium cations (la (unsubstituted), lb (4- bromo), IC (4-aminocarbonyl), Id (4-cyano), le (5-nitro)) have been investigated in basic aqueous solution (pH 9-13) at 25 OC and ionic strength 0.1. In these solutions, these cations are rapidly equilibrated with their C-1 pseudobases, and pseudobase alkoxide ions, and pKR+ and pKRo-have been evaluated. Subsequently, la-lc and le undergo hydroxide ion ...