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Patent / Jan 01, 2006

Process for the preparation of tamsulosin and intermediates thereof starting from chiral phenylethylamine and using catalytic hydrogenation as the key step

  • Zita Mendes
  • Dionisio Martin
  • William Heggie
  • Joana Baptista
WO 2006061549

A process for producing tamsulosof formula I and pharmaceutically acceptable addn. salts, thereof is disclosed. The process comprises the following steps: reacting (R,R)-[2-(4-methoxy-phenyl)-1-methyl-ethyl]-(1- phenyl-ethyl)-amine or a salt thereof with chlorosulfonic acid with or without org. solvent, to obta(R,R)-2-methoxy-5-[2-(1-phenyl-ethylamino)-propyl]-benzenesulfonic acid. Hydrogenolysis of (R,R)-2-methoxy-5-[2-(1-phenyl-ethylamino)-propyl]- benzenesulfonic acid or a salt thereof carried out alc. the presence of a palladium catalyst using hydrogen or a source of hydrogen, to obta(R)-(-)-5-(2-amino-propyl)-2-methoxy-benzenesulfonic acid. Reacting primary amine (R)-(-)-5-(2-amino-propyl)-2-methoxy-benzenesulfonic acid or a salt thereof, with a 2-(2-ethoxyphenoxy)ethyl halide to obta5-[(2R)-2-[2-(2-ethoxy-phenoxy)-ethylamino]-propyl]-2-methoxy-benzenesulfonic acid, which reacted with halogenating agent, to obtathe corresponding sulfonyl chloride, which underwent amidation with ammonia to to give compd.