4-[2-[1-(2-cyano-3-hydroxybut-2-enonylamino)ethyl]-4-ethylsulfamoylbenzo[b]furan-7-yloxy]butyric acid ethyl ester                                                                                                                                                              在
                                                                                                                                                                                 
sodium hydroxide                                                                                                                                  作用下,
                                                                                                                以
                                                                                         
乙醇                                                                                  为溶剂,
                                                                                                                                                    反应 2.5h,
                                                                                                                以44.7%的产率得到4-[2-[1-(2-cyano-3-hydroxybut-2-enonylamino)ethyl]-4-ethylsulfamoylbenzo[b]furan-7-yloxy]butyric acid