The invention concerns compounds of general formula (I) (wherein R and R represent an alkyl radical or an aryl group and R" is hydrogen or a CO—R¹ group wherein R¹ is an alkyl radical or an aryl group; and the dimers formed by the disulphide bond from one and/or the other of the two sulphur atoms of the compounds of general formula (I); and the corresponding thiazolidin forms), the methods for preparing them and uses thereof. More particularly, it concerns the use of said compounds as antioxidant agents, in particular for preparing medicines designed to increase the intracellular and/or extracellular level of glutathione (GSH).