ethyl (E)-3-[2-(1,3-dihydro-4-hydroxy-6-methoxy-7-methyl-3-oxoisobenzofuran-5-yl)ethylidene]cyclopentane-1-carboxylate                                                                                                                                                                                              以
                                                                                         
dichloromethane hexane                                                                                  为溶剂,
                                                                                                                                                                                        以is obtained (E)-3-[2-(1,3-dihydro-4-hydroxy-6-methoxy-7-methyl-3-oxoisobenzofuran-5-yl)ethylidene]cyclopentane -1-carboxylic acid, m.p. 128°-130° C. (hexane-dichloromethane)的产率得到(E) 3-[2-(1,3-dihydro-4-hydroxy-6-methoxy-7-methyl-3-oxoisobenzofuran-5-yl)ethylidene]cyclopentane-1-carboxylic acid