Anhydrous tetrahydrofuran (2.5 ml) was added to a mixture of 1-(2-hydroxyethyl)-1-phenethyl-3-[3-(4-pyridyl)propyl]thiourea (Compound No. 7-2) (601 mg, 1.75 mmol) and triphenylphosphine (913 mg, 3.49 mmol), and the whole was stirred under ice/methanol-cooling. A solution of diisopropyl azodicarboxylate (710 mg, 3.49 mmol) in anhydrous tetrahydrofuran was added dropwise thereto, and after 10 minutes, ethyl acetate (100 ml) was added to the reaction mixture. The whole was washed with a saturated aqueous sodium bydrogencarbonate solution (40 ml) and saturated brine (40 ml) successively, and the organic layer was dried over sodium sulfate and concentrated under reduced pressure. The residue was purified by silica gel column chromatography, and the obtained solid was filtered off with hexane to give 107 mg (19%) of the titled compound as crystals.
