| abstract |
Compounds of formula (I) wherein: R1, R2 which are the same or different, are a hydrogen atom, or a -(CH2)m-O-(CH2)n-R3 group, wherein R3 is an aryl residue, m is an integer 1 to 5 and n is an integer 1 to 4, with the proviso that R1 and R2 cannot be at the same time hydrogen, as well as the optically active forms of the chelates thereof with Mn(II) and the salts thereof with physiologically compatible organic bases selected from primary, secondary, tertiary amines or basic amino acids, or with inorganic bases whose cations are sodium, potassium, magnesium, calcium, or mixtures thereof, are disclosed. |