4-Amino-N-(3-amino-2-hydroxy-4-phenyl-butyl)-N-isobutyl-benzenesulfonamide → N-((2R,3S)-3-Amino-2-hydroxy-4-phenylbutyl)-N-(2-methylpropyl)-4-aminobenzenesulfonamide

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Reaction Conditions

Reaction Steps

The obtained solution was then cooled to 40±3° C. followed by the addition of water. Adjustment of the pH of the solution to around 9.5 with aqueous solution of sodium hydroxide gave crystals 4-Amino-N-(3-amino-2-hydroxy-4-phenyl-butyl)-N-isobutyl-benzenesulfonamide. Additional water was added to this solution to adjust the concentration of 4-Amino-N-(3-amino-2-hydroxy-4-phenyl-butyl)-N-isobutyl-benzenesulfonamide to 5.5-5.8 wt %, and then this solution was cooled to 6±4° C. The resulting crystals were filtered off and washed with a mixed solution composed of water and ethanol and then washed with water. The resulting wet crystals were subjected to vacuum drying to give the product of (2R,3S)-N-(3-amino-2-hydroxy-4-phenylbutyl)-N-isobutyl-4-amino-benzenesulfonamide. Yields were 75˜85% based on (1-Benzyl-2-hydroxy-3-[isobutyl-(4-nitro-benzenesulfonyl)-amino]-propyl)-carbamic acid tert-butyl ester.

Provenance & Evidence