Hydrochloric Acid → Benzyl 4-(4-aminophenyl)piperazine-1-carboxylate

Participants

Reaction Steps

To a mixture of 8.0 g benzyl 4-(4-nitrophenyl)piperazine-1-carboxylate (23.5 mmol) and 11 g CoCl2 (47 mmol) in 100 mL MeOH was added 8.6 g (225 mmol) of NaBH4 portion-wise and then stirred at rt for 1 hr. To the reaction mixture was added 3N HCl until the black precipitate dissolved. The resulting mixture was concentrated to remove MeOH and the residue was extracted twice with ether. The aqueous layer was basified with 1N NaOH and then extracted twice with ethyl acetate. The combined extracts were concentrated to give an oil that was purified by MPLC chromatography (ISCO, 50% hexane/ethyl acetate, 40 g+12 g stacked column) to give 5.8 g of benzyl 4-(4-aminophenyl)piperazine-1-carboxylate. LCMS: (M+H)+=312.25.

Provenance & Evidence