(2R,3S)-1-[4-(2-Ethyl-benzyloxy)-benzenesulfonyl]-3-methyl-piperazine-2-carboxylic acid tert-butyl ester

(2R,3S)-3-(2-Hydroxy-ethylamino)-2-[4-(2-methyl-benzyloxy)-benzenesulfonylamino]-butyric acid tert-butyl ester

(2R,3S)-1-[4-(Isoquinolin-4-ylmethoxy)-benzenesulfonyl]-3-methyl-piperazine-2-carboxylic acid tert-butyl ester

(2R,3S)-1-[4-(5-Fluoro-2-methyl-benzyloxy)-benzenesulfonyl]-3-methyl-piperazine-2-carboxylic acid tert-butyl ester

(2R,3S)-4-Acetyl-3-methyl-1-[4-(2-methyl-pyridin-3-ylmethoxy)-benzenesulfonyl]-piperazine-2-carboxylic acid tert-butyl ester