5-benzyloxymethyl-3-bromo-1-(2-trimethylsilylethoxymethyl)-1,5-dihydropyrrolo[2,3-d]pyridazin-4-one 、
3-bromo-1,5-bis(2-trimethylsilylethoxymethyl)-1,5-dihydropyrrolo[2,3-d]pyridazin-4-one 、
甲基硼酸 以respectively, whereby 25.3 g of the title compound was obtained as a brownish oil的产率得到5-benzyloxymethyl-3-methyl-1-(2-trimethylsilylethoxymethyl)-1,5-dihydropyrrolo[2,3-d]pyridazin-4-one