1. A study was made of the reaction of p-dimethylaminobenzyldiethylamine, p-dimethyiaminobenzyl ethyl ether, p-methoxybenzyl ethyl ether and p-methoxybenzyl acetate with triethyl phosphite. The compounds, containing the dimethylamino group in the p-position, react with triethyl phosphite in the presence of acetic acid to give the diethyl ester of p-dimethylaminobenzylphosphonic acid. The other analogs do not react with triethyl phosphite. 2. The methiodides of p-dimethylaminobenzyldiethylamine and diethylbenzylamine react with triethyl phosphite to give respectively the p-dimethylaminobenzyl- and benzylphosphonates.