A New Process for the Synthesis of R‐nosylate a Key Intermediate of Nafithromycin

Abstract Present study described the facile and efficient synthesis of R ‐nosylate (chemical name: ( R )‐1‐(5‐(pyridin‐2‐yl)‐1,3,4‐thiadiazol‐2‐yl)‐ethyl,4‐nitrobenzenesulfonate) as new key intermediate of nafithromycin. The R ‐nosylate ( 3 b ) was prepared in six steps, starting from readily available methyl‐ D ‐lactate. To produce a 3 b with a good yield and remarkable chiral high performance liquid chromatography (CHPLC) purity more than 99 %, a large‐scale practical and environmentally friendly process was generated and optimized. The developed method, which was successfully established at the pilot scale and then used as the base for industrial production, considerably decreased the use of harmful reagents.