1-(4-fluorophenyl)-3-(R)-[(4-fluorobenzoyl)methylthio]-4-(R)-{4-[N-(α-(R)-{N-[2-(t-butoxy)-(1S)-(t-butoxycarbonyl)ethyl]carbamoyl}benzyl)carbamoylmethoxy]phenyl}azetidin-2-one

{4-[(2R,3R)-3-[2-(2,3-dihydro-benzofuran-6-yl)-2-oxo-ethylsulfanyl]-1-(4-fluoro-phenyl)-4-oxo-azetidin-2-yl]-phenoxy}-acetic acid

N-({4-[(2R,3R)-3-{[2-(2,3-dihydro-1-benzofuran-5-yl)-2-oxoethyl]thio}-1-(4-fluorophenyl)-4-oxoazetidin-2-yl]phenoxy}acetyl)glycine

(R)-3-cyclohexyl-2-(2-(2-(4-((2R,3R)-3-((2-(2,3-dihydrobenzofuran-5-yl)-2-oxoethyl)thio)-1-(4-fluorophenyl)-4-oxoazetidin-2-yl)phenoxy)acetamido)acetamido)propanoic acid