To a solution of 3,5-di-t-butyl-4-hydroxybenzoic acid (5.0 g) in methylene chloride (20 ml) was added dicyclohexylcarbodiimide (2.17 g) and the mixture was stirred overnight at room temperature. Subsequently, triethylamine (2.1 ml), 4-dimethylaminopyridine (0.37 g) and o-phenylenediamine (1.08 g) were added and the mixture was stirred overnight at room temperature. The insolubles was filtered off and the filtrate was concentrated to dryness. The residue was purified by a silica gel column chromatography (chloroform:ethyl acetate=20:1) and crystallized from diisopropyl ether to give N-(2-aminophenyl)-3,5-di-t-butyl-4-hydroxybenzamide (1.10 g, 32%).
