[OH:1][C:2]1[CH:3]=[C:4]2[C:8](=[CH:9][CH:10]=1)[NH:7][N:6]=[CH:5]2.C(=O)([O-])[O-].[K+].[K+].I[CH2:18][CH3:19].C(OCC)(=O)C>CC(C)=O.CCCCCC>[CH2:18]([O:1][C:2]1[CH:3]=[C:4]2[C:8](=[CH:9][CH:10]=1)[NH:7][N:6]=[CH:5]2)[CH3:19]
A solution of 5-hydroxy-1H-indazole [0.5 g, Reference Example 38] in acetone (10 ml) was treated with potassium carbonate (2.56 g) then with iodoethane (0.296 ml). The mixture was refluxed for 4 hours then cooled and then evaporated. The residue was partitioned between ethyl acetate and water and the aqueous layer was further extracted twice with ethyl acetate. The combined organic fractions were dried over magnesium sulfate and then evaporated to yield a brown residue which was subjected to flash column chromatography on silica eluting with a mixture of ethyl acetate and hexane (1:1, v/v) to give 5-ethoxy-1H-indazole (0.38 g) as an off-white solid. LC-MS (METHOD B): RT=2.68 minutes; 163 (M+H)+.
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