1.4 g palladium on charcoal (10%/50% moisture) was added to a solution of 6.9 g (21.44 mmol) (RS)-S-cyclopropyl-S-(4-nitrophenyl)-N-(trifluoroacetyl)sulfoximide in 214 ml ethanol and 39 ml THF and was hydrogenated for 1 hour under normal pressure at 25° C. A further 1.4 g palladium on charcoal was added, and it was hydrogenated for a further 4.5 hours at normal pressure. The mixture was filtered, 1.4 g palladium on charcoal was added to the filtrate again and finally hydrogenated for 45 minutes. The mixture was filtered and concentrated by evaporation. 5.8 g (19.91 mmol; yield: 93%) of the product was obtained.
