Atorvastatin → Atorvastatin

Participants

Reaction Steps

The benethamine salt of atorvastatin (Form B) was synthesized by preparing a stock solution of the free acid of atorvastatin (U.S. Pat. No. 5,273,995) in 2-propanol (IPA) (1 g in 40 mL of IPA). A solution of N-benzyl-2-phenylethylamine (benethamine) was prepared by dissolving 388.68 mg (1.1 equivalents) in 2-propanol (100 mL). The stock solution of atorvastatin free acid was added to the counterion solution with stirring. Seed crystals of the benethamine salt were added. The mixture was reduced to a wet solid under a nitrogen bleed, and the resulting solids were slurried in 2-propanol (40 mL). After 7 days of stirring at ambient temperature, the solids were isolated by vacuum filtration using a Buchner funnel fitted with a paper filter (#2 Whatman). The solids were rinsed with 2-propanol (25 mL), and placed in a 25° C. oven under nitrogen to dry overnight to afford atorvastatin benethamine Form B.

Provenance & Evidence