The condensation of 4-(pivaloyloxy)benzenesulfonyl chloride (I) with the glycine benzyl ester (II) in pyridine gives N-[2-[4-(pivaloyloxy)phenylsulfonamido]benzoyl]glycine benzyl ester (III), which is then debenzylated by hydrogenolysis with H2 over Pd/C in methanol. The starting compounds (I) and (II) are obtained as follows: 1) The condensation of pivaloyl chloride (IV) with 4-hydroxybenzenesulfonic acid (V) by means of NaOH in THF - water gives 4-(pivaloyloxy)benzenesulfonic acid (VI), which is then treated with SOCl2 to afford the corresponding acyl chloride (I). 2) The condensation of 2-nitrobenzoyl chloride (VII) with glycine benzyl ester (VIII) by means of triethylamine in dichloromethane gives N-(2-nitrobenzoyl)glycine benzyl ester (IX), which is then reduced with Fe - HCl in THF - water to the amino derivative (II).

The condensation of 4-(pivaloyloxy)benzenesulfonyl chloride (I) with the glycine benzyl ester (II) in pyridine gives N-[2-[4-(pivaloyloxy)phenylsulfonamido]benzoyl]glycine benzyl ester (III), which is then debenzylated by hydrogenolysis with H2 over Pd/C in methanol. The starting compounds (I) and (II) are obtained as follows: 1) The condensation of pivaloyl chloride (IV) with 4-hydroxybenzenesulfonic acid (V) by means of NaOH in THF - water gives 4-(pivaloyloxy)benzenesulfonic acid (VI), which is then treated with SOCl2 to afford the corresponding acyl chloride (I). 2) The condensation of 2-nitrobenzoyl chloride (VII) with glycine benzyl ester (VIII) by means of triethylamine in dichloromethane gives N-(2-nitrobenzoyl)glycine benzyl ester (IX), which is then reduced with Fe - HCl in THF - water to the amino derivative (II).

The condensation of 4-(pivaloyloxy)benzenesulfonyl chloride (I) with the glycine benzyl ester (II) in pyridine gives N-[2-[4-(pivaloyloxy)phenylsulfonamido]benzoyl]glycine benzyl ester (III), which is then debenzylated by hydrogenolysis with H2 over Pd/C in methanol. The starting compounds (I) and (II) are obtained as follows: 1) The condensation of pivaloyl chloride (IV) with 4-hydroxybenzenesulfonic acid (V) by means of NaOH in THF - water gives 4-(pivaloyloxy)benzenesulfonic acid (VI), which is then treated with SOCl2 to afford the corresponding acyl chloride (I). 2) The condensation of 2-nitrobenzoyl chloride (VII) with glycine benzyl ester (VIII) by means of triethylamine in dichloromethane gives N-(2-nitrobenzoyl)glycine benzyl ester (IX), which is then reduced with Fe - HCl in THF - water to the amino derivative (II).