[O:1]1[CH2:5]CCC1.[F:6][C:7]1[C:8]([C:16]([F:19])([F:18])[F:17])=[CH:9][C:10]([C:13]([NH2:15])=O)=[N:11][CH:12]=1.C(N1C=CN=C1)([N:22]1C=CN=C1)=O.N12CCCN=C1CCCCC2.[OH2:43]>>[F:6][C:7]1[C:8]([C:16]([F:19])([F:18])[F:17])=[CH:9][C:10]([C:13]2[NH:22][O:43][C:5](=[O:1])[N:15]=2)=[N:11][CH:12]=1To 4 ml of tetrahydrofuran were added 0.4 g of 5-fluoro-4-trifluoromethylpyridine-2-carboxamide=oxime and 0.41 g of 1,1′-carbonyldiimidazole, and the mixture was stirred at room temperature for 2 hours. Thereafter, 0.38 g of 1,8-diazabicyclo[5,4,0]undec-7-ene was added, and the mixture was stirred for 9 hours. To the reaction solution were added water and a 10% aqueous HCl solution, the resultant solution was extracted with ethyl acetate three times, and the organic layers were combined, dried with anhydrous magnesium sulfate, and concentrated. The residue was subjected to silica gel column chromatography to obtain 0.35 g of 3-(5-fluoro-4-trifluoromethylpyridin-2-yl)-1,2,4-oxadiazol-5-one (present compound (52)).
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