Process for the preparation of tetraazamacrocycles

A process for the preparation of compounds of formula (I) ##STR13## in which n, p and q can independently be 0 or 1,

• comprising the following steps according to the Scheme:
• ##STR14## wherein step a):
• condensation of the polyamine of formula (III) with the glyoxal derivative of formula (IV), wherein Y is --OH (glyoxal hydrate) or [--SO.sub.3.sup.- Na.sup.+] (Bertagnini's salt), in water or in water-soluble solvents or in mixtures thereof, at a temperature of 0 to 50.degree. C., in the presence of stoichiometric amounts or of a slight excess of calcium hydroxide, to give the compound of formula (V);
• step b):
• condensation of the compound of formula (V) with an alkylating agent X--CH.sub.2 --(CH.sub.2).sub.q --CH.sub.2 --X, in which q is as previously defined and X is Cl or Br, in ratios of 1 to 5 mols per mol of compound (V), in a dipolar aprotic solvent and in the presence of a base selected from alkali or alkaline-earth metal carbonates, in ratios of 5 to 10 mols per mol of compound (V), and with the addition of NaZ, wherein Z is I or Br, as catalyst in ratios of 0.1 to 2 mols per mol of compound (V), wherein
• X and Z are not at the same time Br, at a temperature from 25 to 150.degree. C., to give the compound of formula (I).