Iodinated vicinal-diol-based compounds and radiopaque hydrogels formed from same

A method of making a polyiodinated polyamino compound comprising:

• reacting a polyiodinated aromatic compound that comprises a plurality of vicinal diol groups in an ester coupling reaction with a molar excess of a carboxylic-acid-substituted polyamino compound in which amino groups are protected, thereby forming a product mixture that comprises (a) a polyiodinated polyamino compound comprising a single residue of the polyiodinated aromatic compound and a single residue of the carboxylic-acid-substituted polyamino compound in which the amino groups are protected and (b) a polyiodinated polyamino compound comprising a single residue of the polyiodinated aromatic compound and two or more residues of the carboxylic-acid-substituted polyamino compound in which the amino groups are protected;
• deprotecting the amino groups to provide a product mixture that comprises (a) a polyiodinated polyamino compound comprising the single residue of the polyiodinated aromatic compound and a single residue of the carboxylic-acid-substituted polyamino compound and (b) a polyiodinated polyamino compound comprising the single residue of the polyiodinated aromatic compound and two or more residues of the carboxylic-acid-substituted polyamino compound;
• and
• separating the polyiodinated polyamino compound comprising the single residue of the polyiodinated aromatic compound and the single residue of the carboxylic-acid-substituted polyamino compound from the polyiodinated polyamino compound comprising the single residue of the polyiodinated aromatic compound and the two or more residues of the carboxylic-acid-substituted polyamino compound.