(3S,4R,1'S)-3-t-butoxycarbonylamino-1-(1'-phenyl-ethyl)-4-(tetrahydropyran-2-yloxymethyl)pyrrolidin-2-one
methyl (3R,4S)-{4-(tert-butoxycarbonylamino)-1-[(1S)-1-(4-methoxyphenyl)ethyl]-5-oxopyrrolidin-3-yl}carboxylate
(3R,4S)-{4-(tert-butoxycarbonylamino)-1-[(1S)-1-(4-methoxyphenyl)ethyl]-5-oxopyrrolidin-3-yl}carboxylic acid
(3S,4R,1S')-3-t-butoxycarbonylamino-4-methoxycarbonyl-1-(1'-phenylethyl)pyrrolidin-2-one
(3S,4R,1'S)-3-t-butoxycarbonylamino-4-hydroxymethyl-1-(1'-phenylethyl)pyrrolidin-2-one