Ethyl 2-bromopropionate → Piperidin-1-yl-acetic acid

Ethyl 2-bromopropionate (0.0001 mol) was added to a mixture of intermediate (12) (0.000084 mol) and tri-n-butylthiourea (TBTU) (0.000168 mol) in DIPEA (4 ml). The reaction mixture was shaken for 2 hours at 70° C. The reaction mixture was cooled to room temperature, filtered and the filtrate was evaporated. The residue was dissolved in DCM (4 ml), then washed with water (2 ml). The mixture was filtered through Extrelut™ and the filter residue was washed with DCM (2×3 ml). The filtrate was evaporated. The residue was purified by HPLC (Waters column, with Xterra MS C18; eluent: [(0.5% NH4OAc in H2O)/CH3CN 90/10)]/CH3CN (0 min) 85/15, (10 min) 10/90, (16 min) 0/100, (18.10-20.00 min) 85/15), yielding 1-piperidineacetic acid, α-phenyl-4-[4-[[[4′-(trifluoromethyl)[1,1′-biphenyl]-2-yl]carbonyl]amino]phenyl]-, 2-ethoxy-1-methyl-2-oxoethyl ester (compound 111).