The application relates to a process for the synthesis of organic sulfonic acid salts of amino acid esters comprising the steps of (i) reacting at least one lactam with at least 3 carbon atoms in the lactam ring with at least one organic sulfonic acid in an aqueous solution, (ii) esterification of the organic sulfonic amino acid salt of step (i) with at least one alcohol with at least 8 carbon atoms comprising at least one hydroxyl group, (iii) optionally removal of water and/or removal of excess alcohol of step (ii). The application also relates to organic sulfonic acid salts of amino acid esters of the general formula (I).