A process for the preparation of 4-O-[(N-(3-methyl-2-amino-butyryl-piperidinyl) sulfanyl)acetyl]mutilins of formulafeasible for large-scale production of high purity products, and wherein the carbon atom at the piperidine ring attached to the sulphur atom is either in the (S)-configuration or in the (R)-configuration, and a new crystalline form of 14-O-[(N-3-methyl-2-(R)-amino-butyryl-piperidine-3(S)-yl)sulfanyl]acetyl]mutilin -hydrochloride.一種用於製備具有下式的14-O-[(N-(3-甲基-2-胺基-丁醯基-哌啶基)硫基)乙醯基]側耳菌素類(mutilins)之方法,其可用於大規模製造高純度產物,且其中在哌啶環上接於硫原子的碳原子係呈(S)-構型或呈(R)-構型;及一種14-O-[(N-(3-甲基-2-(R)-胺基-丁醯基-哌啶-3(S)-基)硫基)乙醯基]側耳菌素-鹽酸鹽的新結晶形式。
