1,1-Dimethylethyl 4-[(5-methoxy-4-chloro-2-nitrophenyl)amino]-piperidinecarboxylate (D47) (400 mg) was dissolved in ethanol (10 ml) and Raney nickel (50% aqueous suspension, 1.0 ml) was added at room temperature; the mixture was heated to 40° C. and hydrazine monohydrate (0.5 ml) was added over 30 min. After 30 min more, the reaction mixture was cooled to room temperature, filtered through Celite evaporated and chromatographed on silica gel eluting with ethyl acetate-hexane mixtures to yield the title compound, 300 mg.
