The invention concerns compounds of general formula (I), wherein: A represents one of the radicals in which R.sup.5 represents independently a hydrogen atom, or alkyl; R.sup.6, R.sup.7 and R.sup.8 independently represent a hydrogen atom, alkyl, cycloalkyl, hydroxy or alkoxy; R.sup.11 represents a hydrogen atom of alkyl; and R.sup.9, R.sup.10 and R.sup.12 independently represent a hydrogen atom, alkyl, hydroxy or alkoxy; B represents a hydrogen atom or alkyl; n represents an integer from 0 to 5; R.sup.1 and R.sup.2 independently represent a hydrogen atom, alkyl or cycloalkyl; R.sup.3 and R.sup.4 independently represent a hydrogen atom or an alkyl radical, or R.sup.3 and R.sup.4 together form with the nitrogen atom which bears them a heterocycle optionally substituted comprising in all 1 to 2 heteroatoms and 5 to 7 members. Said compounds can be used for preparing a medicine for protecting mitochondria, and in particular a medicine for preventing or treating cirrhosis. ##STR00001##