phenylmethyl 2-[[2-(acetylsulfanylmethyl)-3-phenylbutanoyl]amino]acetate phenylmethyl 2-[[2-(acetylsulfanylmethyl)-3-phenyl-butanoyl]amino]acetate 2-[[2-[(acetylthio)methyl]-1-oxo-3-phenylbutyl]amino]acetic acid phenylmethyl ester 2-[[2-[(acetylthio)methyl]-3-phenyl-butanoyl]amino]acetic acid benzyl ester phenylmethyl 2-[[2-(ethanoylsulfanylmethyl)-3-phenyl-butanoyl]amino]ethanoate