p-Nitrobenzyl alpha-[4-mercapto-3-phenoxyacetamido-2-oxoazetidin-1-yl]-alpha-(2-bromo-1-hydroxyethylidene)acetate                                                                                                                                                              在
                                                                                                                                                                                 silica gel   、                                                                                                  
氯仿                                                                                                                                  作用下,
                                                                                                                以
                                                                                         
苯                                                                                  为溶剂,
                                                                                                                                                    反应 1.0h,
                                                                                                                以to give p-nitrobenzyl 3-hydroxy-7-phenoxyacetamido-3-cephem-4-carboxylate (60 mg)的产率得到para-nitrobenzyl 7-(R)-phenoxyacetamido-3-hydroxy-3-cephem-4-carboxylate