A series of 4-and 5-[2, 3-dihydro-6, 7-bis [[~ N-alkylcarbamoyl) oxy] methyl]-l~-pyrrolizin-5-yl]- 2-haloppidinium iodides were synthesized. The rates of hydrolysis of the a-halopyridinium salts to the corresponding pyridones, and the reactivities of the carbamate moieties were studied as a function of pH, buffer composition, and ionic strength. The 4-and 5-pyrrolizinyl-2- halopyridinium iodides and the corresponding pyridones were evaluated against P388 ...