[CH:1]1([O:6][C:7]2[CH:8]=[C:9]([CH:19]=[CH:20][C:21]=2[O:22][CH3:23])[CH2:10][NH:11][C:12]2[C:16]([CH2:17][OH:18])=[CH:15][NH:14][N:13]=2)[CH2:5][CH2:4][CH2:3][CH2:2]1.O.[C:25]1(C)C=CC(S(O)(=O)=O)=CC=1.[OH-].[Na+]>CO>[CH:1]1([O:6][C:7]2[CH:8]=[C:9]([CH:19]=[CH:20][C:21]=2[O:22][CH3:23])[CH2:10][NH:11][C:12]2[C:16]([CH2:17][O:18][CH3:25])=[CH:15][NH:14][N:13]=2)[CH2:5][CH2:4][CH2:3][CH2:2]1A solution of 3-(3-cyclopentyloxy-4-methoxybenzylamino)-4-hydroxymethylpyrazole (1.0 g, 3.15 mmol) and p-toluenesulfonic acid monohydrate (0.2 g, 1.0 mmol) in methanol (100 mL) was kept at room temperature for 10 min. The reaction mixture was neutralized with 1 N aqueous sodium hydroxide and evaporated under reduced pressure at room temperature. The residue-was partitioned between water (50 mL) and ethyl acetate (50 mL). The layers were separated and the aqueous layer was extracted with ethyl acetate (10 mL). The combined ethyl acetate layers were washed with water and evaporated under reduced pressure. The residue was taken up in a small volume of methylene chloride and applied to a 4 mm silica gel disk on a Chromatotron. Elution with 525 mL of methylene chloride and 275 mL of 1% methanol/methylene chloride removed some impure material. Continued elution with 75 mL of 1% methanol/methylene chloride afforded 380 mg (36%) of pure 3-(3-cyclopentyloxy-4-methoxybenzylamino)-4-methyoxymethylpurazole, mp. 112-115°.
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