| abstract |
A process for the preparation of a crystalline compound of formula (III): ** Formula ** where X is any suitable counterion, comprising (i) preparing a solution of a compound of formula (IV) in an organic solvent, where PG it is a suitable protecting group ** Formula ** (ii) add a suitable acid; ** Formula ** (iii) bring the solution to supersaturation to cause crystal formation; and (iv) isolate the crystals; Where to bring the solution to supersaturation comprises adding an antisolvent that is hexanes or heptanes, cooling the solution to room temperature and reducing the volume of the solution. |