The asymmetric unit of the title compound, C17H25NO7S, contains two independent molecules, which are enantiomers forming a hydrogen-bonded dimer associated with two R2 2(7) patterns. In each molecule, one ethyl group from the two available ethyl ester functional groups is disordered. In one molecule, the ethyl group of the ester function from an - carboxylic acid is positionally disordered over two sets of sites with occupancies of 0.66:0.34. In the second molecule, it is the ethyl group in the -ester function that is disordered over two sets of sites with occupancies of 0.58:0.42.