Patent ID: 8791259

Claim:
A process for the preparation of tenofovir of formula I, comprising the steps of: a) reacting 9-[2-(R)-(hydroxy)propyl]adenine (HPA) of formula III with di-Alk-p-toluene sulfonyloxy methyl phosphonate in presence of a base and a metal salt in an organic solvent to obtain (R)-9-[2-(di-Alk-phosphono methoxy)propyl]adenine of formula II; wherein “Alk” represents C 1-4 alkyl, and wherein the metal salt is represented by the formula MX 2 , wherein M represents a divalent metal cation, and X represents halide, acetate, or trifluoromethane sulfonate; and b) dealkylating the compound of formula II with a suitable dealkylating agent to obtain tenofovir.