Method for preparing 4-amino-N-[(2R,3S)-3-amino-2-hydroxy-4-benzene butyl]-N-isobutyl benzsulfamide

The invention discloses a method for preparing 4-amino-N-[(2R,3S)-3-amino-2-hydroxy-4-benzene butyl]-N-isobutyl benzsulfamide. The method comprises the following steps: S1: enabling L-phenylalanine and diazomethane to react to obtain a diazo methyl ketone intermediate product, and enabling the diazo methyl ketone intermediate product and haloid acid to react to obtain a compound A; S2, conducting carbonyl deoxidation on the compound A to obtain a compound B; S3, under the existence of iso-butylamine, conducting cyclization reaction and ring-opening reaction on the compound B in sequence to obtain a compound C; S4, enabling the compound C and nitrobenzenesulfonyl chloride to react to obtain a compound D; S5, conducting nitro reduction on the compound D to obtain the 4-amino-N-[(2R,3S)-3-amino-2-hydroxy-4-benzene butyl]-N-isobutyl benzsulfamide. The method is simple in course, low in cost, mild in condition, and higher in intermediate product stability, and is beneficial for industrial application.