honic acid (dronic acid) derivatives applied in the treatment of bone diseases. Methods: Ibandronate was synthesized from N-methyl-N-pentyl-β-alanine using phosphorus trichloride and phosphorous acid in different ratios, applying sulfolane as the solvent (1.), or under solvent-free conditions (2.), or in ionicliquids as additives (3.). Results: In the first two cases (1. and 2.), using phosphorus