3-吡啶羧酸,4-乙氧基乙酯   、                                                                                      p-toluenesulphonic acid (5-methoxybenzocyclobuten-1-yl)methyl ester                                                                                                                                                                                              以
                                                                                         
乙醇                                                                                  为溶剂,
                                                                                                                                                    反应 72.0h,
                                                                                                                以1-[(5-methoxy- benzocyclobuten-1-yl)methyl]-3-ethoxycarbonyl-4-ethoxypyridinium tosylate is obtained in the form of a light-yellow foam的产率得到1-[(5-methoxybenzocyclobuten-1-yl)methyl]-4-ethoxy-3-ethoxycarbonylpyridinium tosylate