Processes for preparing losartan and losartan potassium

Abstract From the Canadian patent

Losartan is prepared by acid catalyzed cleavage of a triarylmethyl group from a triarylmethyl-substituted losartan derivative in a diluent comprising liquid ketone. The reaction mixture is basified and liquid ketone is evaporated from the mixture leaving a residue from which a triarylmethyl alcohol and losartan are each obtained in high yield and high purity. In addition losartan , potassium is prepared by a process that is more convenient that those previously known in the art in which losartan is contacted with potassium ions in substantially pure liquid alcohol and losartan potassium is precipitated from the alcohol.