“Greener” Synthesis of Zoledronic Acid from Imidazol-1-yl-acetic Acid and P-Reagents Using Diethyl Carbonate as the Solvent Component

The synthesis of a third generation dronic acid, zoledronic acid by the reaction of imidazol- 1-yl-acetic acid with phosphorus trichloride/phosphorous acid in diethyl carbonate (DEC) as a “green” solvent, and in DEC – methanesulfonic acid (MSA) solvent mixtures is described. The earlier not “green” and expensive MSA and sulfolane solvents may be replaced by DEC.