Abstract: New compounds useful as immunoregulatory and antineoplastic agents are amino-acid derivatives of formula: ##STR1## wherein: n is an integer from 1 to 5;R.sup.1 is a hydrogen atom, an alkyl group, a haloalkyl group, a halogen atom, a mercapto group, an alkylmercapto group, a hydroxy group, an alkoxy group, an acyloxy group, a carboxyl group, an alkoxycarbonyl group, an amino group, an alkyl-substituted amino group, an aryl-substituted amino group, an acylamino group, a haloalkoxycarbonylamino group, an alkanesulphonyl group, a nitro group or a cyano group (and, when n is an integer from 2 to 5, the radicals R.sup.1 may be the same or different);R.sup.2 and R.sup.3 may be the same or different and each is a hydrogen atom or an alkyl group;R.sup.