5-(2-(Tert-butoxycarbonyl)hydrazono)-5-(4-fluorophenyl)pentanoic acid → Tert-butyl 2-(4-fluorophenyl)-6-oxopiperidin-1-ylcarbamate

Participants

Reaction Steps

Step AAG (2): 10% Palladium on carbon (0.5 g) was carefully added to a solution of 5-(2-(tert-Butoxycarbonyl)hydrazono)-5-(4-fluorophenyl)pentanoic acid (2.3 g, 7.09 mmol) in MeOH (30 mL) in a Parr hydrogenation bottle under nitrogen. The bottle was repeatedly evacuated and flushed with H2 gas (50 psi). The mixture was shaken for 5 h. The vessel was flushed with nitrogen. The reaction contents were filtered through diatomaceous earth (Celite®). The plug and vessel were washed with fresh methanol. The filtrates were combined and concentrated in vacuo. The crude product was purified using silica gel column chromatography (10-80, EtOAc/chloroform, linear gradient) to afford tert-butyl 2-(4-fluorophenyl)-6-oxopiperidin-1-ylcarbamate (1.2 g, 55% yield). 1H NMR (500 MHz, chloroform-d) δ ppm 7.13-7.20 (an, 2 H) 7.06 (t, J=8.55 Hz, 2 H) 6.40 (br. s., 1 H) 4.91 (br. s., 1 H) 2.52-2.75 (m, 2 H) 2.20-2.40 (m, 1 H) 1.77-1.93 (m, 3 H) 1.44 (s, 9 H).

Provenance & Evidence