Water → 220129-58-8

Participants

Reaction Conditions

Reaction Steps

To ethyl 2-[4-[2-[[(1S,2R)-2-hydroxy-2-(4-hydroxy-phenyl)-1-methylethyl]amino]ethyl]phenoxy]acetate phosphate (62.0 g) was added 2 mole/L aqueous sodium hydroxide solution (393 mL), and the mixture was heated to 40° C. of internal temperature with stirring to dissolve. 4 Mole/L aqueous phosphoric acid solution (115 mL) was added dropwise to the solution at 40-46° C. of internal temperature. After stirring at room temperature overnight, the resulting crystals were collected by filtration and washed with water to obtain white crystals. The resulting crystals suspended in a mixed solvent (200 mL) of water and methanol (1/8) were heated under reflux for 30 minutes. After cooling to room temperature, the crystals were collected by filtration and dried at 40-50° C. for 3 hours under reduced pressure to give 2-[4-[2-[[(1S,2R)-2-hydroxy-2-(4-hydroxyphenyl)-1-methylethyl]amino]ethyl]-phenoxy]acetic Acid (Crystalline Form α) (50.0 g). A powder X-ray diffraction pattern of the crystalline polymorph (crystalline form α) is shown in the following FIG. 1.

Provenance & Evidence