Novel substituted lactones of amino acids in all their possible stereoisomeric forms or mixtures thereof of the formula ##STR1## wherein A is a hydrocarbon chain of 1 to 10 chain members containing one or more heteroatoms and one or more unsaturations and the chain members being a mono- or polycyclic system or comprises a system of spiro or endo type and may contain one or more chiral atoms or the lactone copula can present a supplementary chirality due to the asymetric spatial configuration of the molecule make up and R is selected from the group consisting of ##STR2## wherein Z is the organic remainder of an amino acid of the formula ##STR3## Y is derived from a primary, secondary or tertiary alcohol of the formula Y--OH and B is the remainder of a heterocyclic amino acid of 3 to 6 carbon atoms of the formula ##STR4## and their preparation and their use for the resolution of amino acids.