乙酸异丙烯酯   、                                                                                      
(6R,7R)-7-{2-[(E)-Methoxyimino]-2-[2-(trityl-amino)-thiazol-4-yl]-acetylamino}-3-methyl-8-oxo-5-thia-1-aza-bicyclo[4.2.0]oct-2-ene-2-carboxylic acid benzhydryl ester                                                                                                                                                              在
                                                                                                                                                                                 
对甲苯磺酸                                                                                                                                  作用下,
                                                                                                                                                                                                                            以42%的产率得到(6R,7R)-7-(Acetyl-{2-[(E)-methoxyimino]-2-[2-(trityl-amino)-thiazol-4-yl]-acetyl}-amino)-3-methyl-8-oxo-5-thia-1-aza-bicyclo[4.2.0]oct-2-ene-2-carboxylic acid benzhydryl ester