Abstract: A novel process for the preparation of N,N′-bis[2,3-dihydroxypropyl]-5-[(hydroxyacetyl) methylamino]-2,4,6-triiodo-1, 3-benzenedi carboxamide of formula (I), commonly known as lomeprol, a novel non-ionic contrast agent which shows very good safety and contrast effectiveness.

Abstract: 1,4,7,10-tetraazacyclododecane-1,4-diacetic acid of formula (I): as well as its chelated complex salts with bi-valent metal ions having atomic numbers from 20 to 31, 39, 42, 43, 44, 49, or from 57 to 83, as well as their salts with anions of physiologically acceptable organic acid selected from acetate, succinate, citrate, fumarate, maleate, oxalate, or with anions of inorganic acids selected from halo acids ions. The compounds are intermediates for preparing 1,4,7,10-tetraaza-cyclododecane chelating agents.

Abstract: Compounds of formula (I) in which R is in which R is hydrogen, a straight or branched or cyclic C1-C6 alkyl group, unsubstituted or substituted by 1 to 10 oxygen atoms, or a C1-C20 alkyl group, optionally interrupted by a phenylene, in turn substituted by a straight or branched C1-C6 alkyl group, unsubstituted or substituted by 1 to 3 C1-C7 alkyl groups; the phenylene group being unsubstituted or substituted by alkoxy, carboxy, sulfamoyl, hydroxyalkyl, amino groups; as well as its complexes with a bi- or trivalent metal ion having an atomic number from 20 to 31, 39, 42, 43, 44, 49, or from 57 to 83, as well as its salts with anions of physiologically acceptable organic acids chelated complexes of these compounds are used as contrast agents for nuclear magnetic resonance imaging.