100 μl of hydrazine monohydrate (2.05 mmol) are added to a solution of 650 mg (1 mmol) of ethyl 4′-[3-(1,3-dioxo-1,3-dihydroisoindol-2-yl)propoxy]-3′-(5,5,8,8-tetramethyl-5,6,7,8-tetrahydronaphth-2-yl)biphenyl-4-carboxylate in 50 ml of ethanol. The reaction mixture is stirred overnight at reflux. The reaction is stopped by adding water and hydrochloric acid to pH 4, and then extracted with ethyl acetate. The organic phases are combined and dried over sodium sulfate. The solvents are evaporated off. The residue is purified by chromatography on silica gel (eluent: 70/30 ethyl acetate/methanol). 180 mg of ethyl 4′-(3-aminopropoxy)-3′-(5,5,8,8-tetramethyl-5,6,7,8-tetrahydronaphth-2-yl)biphenyl-4-carboxylate are obtained in the form of a whitish solid (m.p.=155° C., yield=35%).
