Ammonium formate → 3(2H)-Benzofuranone, 5-amino-2,2,6,7-tetramethyl-

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Reaction Steps

A mixture of 2,2,6,7-tetramethyl-5-nitro-1-benzofuran-3(2H)-one obtained in Reference Example 46 (5.0 g, 21.3 mmol), 10%-palladium carbon (50% hydrous, 500 mg) and ammonium formate (7.06 g, 85.0 mmol) in methanol (100 mL) was heated under reflux for two hours. The solid material was removed and the filtrate was concentrated under reduced pressure. Water and ethyl acetate were added to the residue to separate the organic layer, and the aqueous layer was extracted with ethyl acetate. The combined organic layer was washed with water, dried over anhydrous sodium sulfate and then concentrated under reduced pressure. The solvent was distilled off under reduced pressure to obtain a residue, which was crystallized with ethyl acetate-hexane to obtain 4.0 g (yield 92%) of the title compound. Melting point: 149-150° C.

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