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 (19.35 gm of 90% cal grade, 0.110 mole) in 150 ml water was added. Th 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 (63.4 gm, 84.6% yield) 99.3 ec by chiral HPLC.

Provenance & Evidence