Patent ID: 8921583

Claim:
A method for the preparation of a crystalline compound of Formula (III), wherein X is trifluorocetate, comprising (i) preparing a solution of a compound of Formula (IV) in an organic solvent, wherein PG is a suitable protecting group (ii) adding trifluoroacetic acid; (iii) bringing the solution to supersaturation to cause formation of crystals; and (iv) isolating the crystals, wherein said crystalline compound has 2θ values of 8.84; 15.18; 15.32;16.20; 16.82; 17.66; 18.26; 19.10; 21.20; 22.58; 23.06; 23.52; 25.32; 26.58; 28.60; 30.08; 30.48; 30.84; 32.20; 36.14; and 37.12.