Synthesis of 2-((2-(4-(Benzyloxy)-4-oxobutanamido)ethyl)dimethylammonio)propane-1-sulfonate and 2-((2-(5-(Benzyloxy)-5-oxopentanamido)ethyl)dimethylammonio)propane-1-sulfonate

Two previously undescribed sulfobetaine zwitterions bearing benzyl ester and amide functionalities were synthesized through a concise three-step sequence starting from benzyl alcohol and either succinic or glutaric anhydride. The route comprised esterification, amidation with -dimethylpropane-1,3-diamine, and ring-opening of 1,3-propanesultone by the resulting tertiary amine. Differing only in the length of the diacid-derived spacer, the two compounds constitute a matched pair well suited to probing structure–property relationships in sulfobetaine surfactants and thermoresponsive materials.