4-(3-bromo-4-fluoro-phenyl)-6-ethyl-2-methyl-5-oxo-4,5,6,8-tetrahydro-1H-pyrano[3,4-b]pyridine-3-carboxylic acid methyl ester                                                                                                                                                              在
                                                                                                                                                                                 
吡啶   、                                                                                                  pyridinium hydrobromide perbromide                                                                                                                                  作用下,
                                                                                                                以
                                                                                         
氯仿                                                                                  为溶剂,
                                                                                                                                                    反应 0.58h,
                                                                                                                生成                                                 (-)-cis-9-(3-bromo-4-fluorophenyl)-7-ethyl-5,9-dihydro-3H,4H-2,6-dioxa-4-azacyclopenta[b]naphthalene-1,8-dione