N-tert-butoxycarbonylamino-O-(2,3-difluorobenzyl)-D-serine

(R)-2-Amino-N-[5-(4-chloro-phenyl)-3,3-dimethyl-1,1-dioxo-2,3-dihydro-1H-1λ6-isothiazol-4-ylmethyl]-3-(2,3-difluoro-benzyloxy)-N-ethyl-propionamide

[(R)-1-{[5-(4-Chloro-phenyl)-3,3-dimethyl-1,1-dioxo-2,3-dihydro-1H-1λ6-isothiazol-4-ylmethyl]-ethyl-carbamoyl}-2-(2,3-difluoro-benzyloxy)-ethyl]-carbamic acid tert-butyl ester