、
5-(2,3-dichloro-phenoxy)-2H-pyridazin-3-one 、
Alpha-溴-环戊烷丙酸甲酯 以afforded 3-cyclopentyl-2-[4-(2,3-dichloro-phenoxy)-6-oxo-6H-pyridazin-1-yl]-propionic acid (12 g, 78% for the final step)的产率得到3-cyclopentyl-2-[4-(2,3-dichloro-phenoxy)-6-oxo-6H-pyridazin-1-yl]-propionic acid