[C:1]([O:5][C:6]([C@@H:8]1[CH2:13][CH2:12][C@H:11]([O:14][C:15]2[CH:25]=[CH:24][C:18]([C:19]([O:21]CC)=[O:20])=[CH:17][N:16]=2)[CH2:10][CH2:9]1)=[O:7])([CH3:4])([CH3:3])[CH3:2].O.[OH-].[Li+]>C1COCC1.CO>[C:1]([O:5][C:6]([C@@H:8]1[CH2:13][CH2:12][C@H:11]([O:14][C:15]2[CH:25]=[CH:24][C:18]([C:19]([OH:21])=[O:20])=[CH:17][N:16]=2)[CH2:10][CH2:9]1)=[O:7])([CH3:4])([CH3:2])[CH3:3]1.33 g of ethyl cis-6-(4-tert-butoxycarbonylcyclohexyloxy)nicotinate (3.97 mmol, 1 eq.) are dissolved in 60 mL of a 1/1 mixture of THF/methanol. At 0° C., 0.333 g of lithium hydroxide monohydrate (7.93 mmol; 2 eq.) is added with stirring. After stirring for 16 hours at room temperature, the reaction medium is evaporated and aqueous 6% sulfur dioxide solution is added. The precipitate formed is filtered off and washed with water to give 1.25 g of cis-6-(4-tert-butoxycarbonylcyclohexyloxy)nicotinic acid.
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