Synthesis method of 5, 6-dihydroxyindole and intermediate of 5, 6-dihydroxyindole

The invention provides a synthesis method of 5, 6-dihydroxy indole and an intermediate thereof, the method comprises the following steps: taking 5, 6-dihydroxy indoline halogen acid salt or other acid salt (IC241-01) as a raw material, successively protecting heteroatom nitrogen and phenolic hydroxyl group to obtain an intermediate compound 1-carbobenzoxy-5, 6-dibenzyloxy indoline (IC241-03), and reacting the intermediate compound 1-carbobenzoxy-5, 6-dibenzyloxy indoline (IC241-03) to obtain the 5, 6-dibenzyloxy indoline (IC241-03). The preparation method comprises the following steps: by taking 5, 6-dibenzyloxyindole (IC241-04) as a raw material, further carrying out oxidation reaction to obtain an intermediate compound 1-benzyloxycarbonyl-5, 6-dibenzyloxyindole (IC241-04), and in the presence of a trace amount of antioxidant and polymerization inhibitor, carrying out catalytic hydrogenation to remove a protecting group to obtain 5, 6-dihydroxyindole (DHI). The method disclosed by the invention has the advan