8-methoxy-6-ethoxycarbonyl-3,4-dihydrocarbostyril                                                                                                                                                                                              以
                                                                                         
甲醇                                                                                  为溶剂,
                                                                                                                                                                                        以in the same manner as in Reference Example 10, 0.75 g of 8-methoxy-6-carboxy-3,4-dihydrocarbostyril was obtained as colorless needle-like crystals (recrystallized from methanol)的产率得到8-methoxy-6-carboxy-3,4-dihydrocarbostyril