Patent ID: 6855813
Filing Date: 2005-02-15
Classification: C07H

Abstract:
1. A process for making Azithromycin monohydrate crystals, said process comprising the steps of: (a) dissolving 9-Deoxo-9a-aza-9a-homoerythromycin A in acetonitrile, to form a solution; (b) adding formic acid and formaldehyde to said solution; (c) refluxing said solution to form a reaction mixture; (d) adjusting the pH of said reaction mixture from about 10 to about 11 with alkaline solution; (e) optionally filtering the pH adjusted reaction mixture of step (d); (f) adding water to said reaction mixture to precipitate said Azithromycin monohydrate crystals directly from said reaction mixture; (g) filtering out said Azithromycin monohydrate crystals precipitated in said step (f); and (h) drying said Azithromycin monohydrate crystals, wherein said process is conducted without an extraction step.