1,1-Dimethylethyl 4-[(4-fluoro-5-methyl-2-nitrophenyl)amino]-1-piperidinecarboxylate (D27) (0.96 mmol, 340 mg) in ethanol (20 mL) was treated under argon at room temperature with Raney Nickel (suspension, 50% in water, 0.5 mL) then dropwise with hydrazine hydrate (9.6 mmol, 10 eq) in ethanol over 15 min. The mixture was heated at 45° C. for 50 min. The Raney nickel was filtered off and washed with ethanol. The reaction mixture was concentrated under vacuum to give the title compound (0.88 mmol, 284 mg, 92% yield). M+H=324.16.
