Benzenesulfonic Acid → Amlodipine besylate

Participants

Reaction Steps

68.8 gm (0.122 mole, 95.2% de) R (+) amlodipine hemi L(+) tartarate mono DMSO solvate prepared as per example-2 was suspended in aqueous isopropanol (70 ml IPA: 250 ml distilled water) and a solution of benzene sulfonic acid (21.28 gm of 90% technical grade, 0.122 mole) in 1150 ml water was added. The reaction mixture was stirred for 2 hrs and the slurry was filtered, washed with distilled water, hexane, the solid was dried under vac. at 40° C. till constant weight to give R(+) amlodipine besylate (66.74 gm, 89.1% yield) 98.7 ee by chiral HPLC.

Provenance & Evidence