[CH2:1]([O:3][C:4]([C:6]1[NH:7][C:8]2[C:13]([CH:14]=1)=[CH:12][CH:11]=[CH:10][C:9]=2[O:15]CC1C=CC=CC=1)=[O:5])[CH3:2]>[Pd].C(O)C>[CH2:1]([O:3][C:4]([C:6]1[NH:7][C:8]2[C:13]([CH:14]=1)=[CH:12][CH:11]=[CH:10][C:9]=2[OH:15])=[O:5])[CH3:2]One gram of 10% palladium catalyst on active carbon is added to a solution of 22.2 g of 7-benzyloxyindole-2-carboxylic acid ethyl ester in 500 ml of ethanol and the mixture is hydrogenated for 1 hour with shaking under normal pressure. The reaction solution is then filtered and the filtrate evaporated to dryness under vacuum. The residue is recrystallized from ethanol, yielding 13.3 g of 7-hydroxyindole-2-carboxylic acid ethyl ester, mp 197°-199° C.
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