Ytterbium → (5s)-4-(4-Fluorophenyl)-4-(6-fluoro-3-pyridyl)-5-methyl-2-(1,2,5-thiadiazol-3-yl)-2-imidazoline

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Reaction Steps

Triethylamine (23 mg) and 1,1′-carbonyldiimidazole (37 mg) were added to a solution of 1,2,5-thiadiazole-3-carboxylic acid (30 mg) in tetrahydrofuran (3 mL) in this order, and the mixture was stirred at room temperature for one hour. A solution of (2S)-1-(4-fluorophenyl)-1-(6-fluoro-3-pyridyl)-1,2-propanediamine (50 mg) described in Reference Example 5-1 in tetrahydrofuran (1 mL) was added to the above reaction mixture, and the resultant mixture was stirred at room temperature for 17 hours. The reaction mixture was concentrated in vacuo, and then the obtained residue was dissolved in ethyl acetate. Then the solution was washed with water and saturated sodium chloride aqueous solution in this order, and dried over anhydrous sodium sulfate. Sodium sulfate was removed by filtration, and the organic solvent was evaporated in vacuo. The obtained crude product was dissolved in toluene (0.5 mL). Ytterbium triflomethanesulfonate (12 mg) was added to the solution, and then the mixture was stirred at 100° C. for 10 hours. The reaction mixture was diluted with ethyl acetate, and the dilution was washed with saturated sodium hydrogen carbonate aqueous solution, water and saturated sodium chloride aqueous solution in this order. The mixture was dried over anhydrous sodium sulfate. Sodium sulfate was removed by filtration, and the organic solvent was evaporated in vacuo. The obtained residue was purified by silica gel column chromatography (C-300; hexane: ethyl acetate=2:3) to give the objective compound (37 mg) as colorless oil.

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