p. 900 - 907
(1999)(2008/06/13)
(R)-4-(4-nitrobenzoyloxy)-1-methyl-2-oxopyrrolidine
4-nitrobenzyl (1R,5S,6S)-6-[(R)-1-hydroxyethyl]-1-methyl-2-[(S)-1-methyl-5-oxopyrrolidin-3-ylthio]-1-carbapen-2-em-3-carboxylate
4-nitrobenzyl (1R,5S,6S)-6-[(R)-1-hydroxyethyl]-1-methyl-2-[(R)-1-methyl-5-oxopyrrolidin-3-ylthio]-1-carbapen-2-em-3-carboxylate
pivaloyloxymethyl (1R,5S,6S)-6-[(R)-1-hydroxyethyl]-1-methyl-2-[(S)-1-methyl-5-oxopyrrolidin-3-ylthio]-1-carbapen-2-em-3-carboxylate
pivaloyloxymethyl (1R,5S,6S)-6-[(R)-1-hydroxyethyl]-1-methyl-2-[(R)-1-methyl-5-oxopyrrolidin-3-ylthio]-1-carbapen-2-em-3-carboxylate