4-(2,2-dimethyl-1-oxido-3-oxo-3,4-dihydro-2H-pyrrol-5-yl)benzoic acid                                                                                                                                                              在
                                                                                                                                                                                 
manganese(IV) oxide                                                                                                                                  作用下,
                                                                                                                以
                                                                                         
氯仿                                                                                  为溶剂,
                                                                                                                                                                                        以80%的产率得到4-{3-[2-(4-carboxyphenyl)-5,5-dimethyl-1-oxido-4-oxo-4,5-dihydro-3H-pyrrol-3-ylidene]-5,5-dimethyl-1-oxido-4-oxo-4,5-dihydro-3H-pyrrol-2-yl}benzoic acid