ethyl 4-[(4-nitrobenzoyl)amino]benzoate

ethyl 4-(ethoxycarbonylamino)benzoate

N-(benzyloxycarbonyl)-2-methylalanyl-4-aminobenzoesaure-ethylester

ethyl 4-(2-methylpropylamino)benzoate

ethyl 4-(3,3-diethoxypropylamino)benzoate