[C:1]([N:5]1C(C2C=CC=CC=2)[O:6]1)([CH3:4])([CH3:3])[CH3:2].S(=O)(=O)(O)O.O1CN1.[C:22]([OH:25])(=[O:24])[CH3:23].[OH-].[Na+]>C(O)C.O.C(OCC)(=O)C>[C:22]([O-:25])(=[O:24])[CH3:23].[C:1]([NH2+:5][OH:6])([CH3:4])([CH3:3])[CH3:2]2-tert-Butyl-3-phenyloxaziridine (30.3 g, 98.2area %, 0.17 mol) was dissolved in ethanol (90 g). Sulphuric acid (25.7 g, 95 to 97%, 0.25 mol, 1.5 equiv.) was diluted in water (90 g) and added to the 500 ml reaction bottle. The reaction mixture was stirred at +20° C. for 20 h at which time analysis by GC showed that 5.8 area % oxaziridine remained. Leaving the reaction stirring over the weekend gave complete conversion. The solvents were evaporated and the concentrate was partitioned between water (90 g) and ethyl acetate (90 g). The organic phase was discarded and fresh ethyl acetate (150 g) and acetic acid (10.8 g, 0.18 mol, 1.1 equiv.) were added, followed by sodium hydroxide (45% aqueous solution) until the aqueous phase had approximately pH 5.5. The organic phase was then separated, filtered through K200 filter paper and concentrated giving an oil (17.3 g). This material was distilled at 20 mbar and the fractions distilling above +72° C. were collected giving a clear oil (11.5 g, 45%) that crystallized immediately. Chromatographic purity (GC): 99.5 area %
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