Patent ID: 7534776

Claim:
A process for preparing water-soluble phosphonooxymethyl derivatives comprising the steps of: wherein R—OH represents an alcohol- or phenol-containing drug, n represents an integer of 1 or 2, R 1 is hydrogen, an alkali metal ion, or a pharmaceutically acceptable cation, and R 2 is hydrogen, an alkali metal ion, or a pharmaceutically acceptable cation; wherein the second step comprises i) reacting the R—O—CH 2 Cl with a molar excess of phophoric acid and base in a suitable solvent; ii) removing the solvent from the product of (i) to form a residue, dissolving the residue in water, and acidifying to a pH of about 1 to about 2; iii) exacting the product of (ii); iv) removing solvent from the product of (iii) to form a residue, disolving the residue in water to form a solution, and adjusting the pH of the solution to about 8 to about 11.5; v) extracting the solution with a suitable solvent; vii) optionally removing the solvent from the solution; and viii) precipitating or recrystallizing to obtain the water-soluble phosphonooxymethyl derivatives.