[OH-].[K+].[CH:3]1([O:8][C:9]2[N:14]=[C:13]([C:15]([O:17]C3CCCC3)=[O:16])[CH:12]=[CH:11][C:10]=2[O:23][CH3:24])[CH2:7][CH2:6][CH2:5][CH2:4]1>O.CO>[CH:3]1([O:8][C:9]2[N:14]=[C:13]([C:15]([OH:17])=[O:16])[CH:12]=[CH:11][C:10]=2[O:23][CH3:24])[CH2:4][CH2:5][CH2:6][CH2:7]1Potassium hydroxide (1.98 g) in water (12 mL) is added to a solution of cyclopentyl 6-cyclopentyloxy-5-methoxypyridine-2-carboxylate (3.6 g) in methanol (35 mL) and the mixture stirred at room temperature for 2.5 hours. The solution is concentrated to half of the original volume and diluted with water. The solution is acidified to pH 4 with concentrated hydrochloric acid and the product extracted with ethyl acetate. The extracts are dried (MgSO4) and concentrated to give 6-cyclopentyloxy-5-methoxypyridine-2-carboxylic acid (1.38 g) as a yellow solid, m.p. 96–99° C.
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