C[O:2][C:3](=[O:22])[C:4]1[CH:9]=[C:8]([CH:10]2[CH2:15][CH2:14][O:13][CH2:12][CH2:11]2)[C:7]([O:16][CH2:17][C:18]([F:21])([F:20])[F:19])=[N:6][CH:5]=1.O1CCCC1.[OH-].[Li+].Cl>O>[O:13]1[CH2:14][CH2:15][CH:10]([C:8]2[C:7]([O:16][CH2:17][C:18]([F:21])([F:19])[F:20])=[N:6][CH:5]=[C:4]([CH:9]=2)[C:3]([OH:22])=[O:2])[CH2:11][CH2:12]1In a 25 mL round-bottomed flask, the above prepared 5-(tetrahydro-pyran-4-yl)-6-(2,2,2-trifluoro-ethoxy)-nicotinic acid methyl ester (538 mg, 1.69 mmol, Eq: 1.00) was combined with tetrahydrofuran (4 ml) and water (2 ml) to give a colorless solution. Lithium hydroxide (80.7 mg, 3.37 mmol, Eq: 2) was added and the reaction mixture was stirred at 40° C. TLC after 3 h showed that the reaction was complete. 6 ml H2O and 4.5 ml 1N HCl were added and the white suspension was stirred for 10 min at 0° C. The solid was filtered off, washed with H2O and dried on hv to yield 489 mg of the title compound as white solid; MS (EI) 304.2 (M−H)−.
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