Patent ID: 11891455
Assignee: GALIMEDIX THERAPEUTICS INC
Field: Pharmaceuticals (Chemistry)
Classification: CPC C  A | IPC A  C

Claim 8:
9. A method for preparing ultrapure Form I of (R)-2-[2-amino-3-(indol-3-yl)propionylamino]-2-methylpropionic acid, characterized by an X-ray powder diffraction pattern displaying peaks at °2θ (d value Å) angles 6.75 (13.095), 10.19 (8.678), 11.76 (7.524), 13.56 (6.531), 17.68 (5.017), 18.63 (4.764), 20.15 (4.407), 22.08 (4.026), wherein said ultrapure Form I of the compound has a purity of from about 99.70 area % to about 99.999 area % by IPC-HPLC, the method comprising
(a) mixing compound (R)-2-[2-amino-3-(indol-3-yl)propionylamino]-2-methylpropionic acid with an aqueous HCl to provide a solution of the compound;
(b) cooling the solution to about 5-10° C., followed by adjusting the pH of the solution to about 5.6 with a base;
(c) stirring the solution at about 0-5° C. until precipitation is complete;
(d) isolating the resulting precipitate to obtain Form II of the compound;
(e) mixing the Form II of the compound of step (d) with water to prepare a solution of Form II of the compound;
(f) heating the solution of Form II of step (e) to about 30-35° C. and cooling to room temperature to produce a precipitate; and
(g) isolating and washing the precipitate to give an ultrapure Form I of the compound;
wherein the washing step is optionally repeated for two or three times;
(h) optionally drying at about 45-50° C.; and
(i) optionally repeating steps (a) to (h).