A solution of 2.39 g of 4-(4-piperidinomethyl-2-pyridyloxy) -cis-2-butenylamine and 1.08 g of 4-pyrazolecarboxylic acid in 40 ml of dry dimethylformamide was stirred for 5 minutes, whilst ice-cooling. 1.89 g of diethyl cyanophosphonate and 1.65 ml of triethylamine were added to the mixture, and the resulting mixture was stirred at room temperature for 3 hours. At the end of this time, the reaction mixture was diluted with water and extracted with ethyl acetate. The extract was washed with a saturated aqueous solution of sodium hydrogencarbonate and then with a saturated aqueous solution of sodium chloride, after which it was dried over anhydrous magnesium sulfate. The solvent was then removed by distillation under reduced pressure, and the residue was purified by column chromatography through silica gel, using a 1:9 by volume mixture of methanol and chloroform as the eluent, to give 1.65 g (yield 51%) of the title compound as a white powder, melting at 121°-123° C.
