N-bromobutanimide → tert-Butyl 4-(4-amino-3-bromophenyl)-piperidine-1-carboxylate

Participants

Reaction Steps

A solution of 2.00 g (7.24 mmol) 4-(4-amino-phenyl)-piperidine-1-carboxylic acid tert-butyl ester (as prepared in the previous step) in 40 mL of CH3CN was treated with solid 1.25 g (7.02 mmol) NBS and stirred at RT for 15 min. The solvents were evaporated in vacuo, the residue was taken up in EtOAc (70 mL) and washed with saturated aqueous NaHCO3 (2×50 mL). The combined organic layers were dried (MgSO4) and concentrated in vacuo. Silica gel chromatography of the residue with 10-25% EtOAc-hexanes afforded 3.12 g (97%) of the title compound as a tan solid: Mass spectrum (ESI, m/z): Calcd. for C12H16N2O2Br, 299.0 (M−C4H9+2H), found 299.1/301.1.

Provenance & Evidence