2,6-Di(tertiary-butyl)-4-(4'-carboxyphenylimino)-2,5-cyclohexadien-l-one → 4-(3,5-Di-tertiary-butyl-4-hydroxyanilino)benzoic acid

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Reaction Steps

To a solution of 5.0 g (0.0147 mole) of 2,6-di(tertiary-butyl)-4-(4'-carboxyphenylimino)-2,5-cyclohexadien-1-one in 300 ml of ethanol was added 0.25 g of 5 percent palladium on charcoal. It was subjected to hydrogenation in a Paar apparatus and filtered. This solvent was removed by evaporation under vacuum and the residue was recrystallized from a 5:2 (v/v) ethanol-water mixture to provide light-orange crystals of 4-(3,5-di-tertiary-butyl-4-hydroxyanilino)benzoic acid, m.p. 241°-243° C. Analysis: Calculated for C21H27NO3 : % C, 73.9; % H 8.0; % N, 4.1; Found: % C, 73.9; % H, 7.9; % N, 3.8.

Provenance & Evidence