Sodium hydride (0.48 g) was added to a solution of 2,2,2-trifluoroethanol (2.4 g) in toluene (30 ml) was added, and the mixture was stirred until the generation of hydrogen ceased. As a result, 2,2,2-trifluoroethanol sodium salt was prepared. To the product were added 1-(2-chloro-5-pyridylmethyl)-2-(nitroimino)imidazolidine (5.1 g) synthesized by the method of Example 3 and a catalytic amount of 4-dimethylaminopyridine. The mixture was heated at 80° C. for 10 hours with stirring. After cooling the reaction mixture, the precipitated crystals were collected by filtration, washed with water and ether and then purified by silica gel chromatography to give 1-[2-(2,2,2-trifluoroethoxy)-5-pyridylmethyl]-2-(nitroimino)imidazolidine (1.5 g).
