HCID 10644854, compound → (S)-3-Amino-4-phenylbutanoic acid

Participants

Reaction Steps

The 3(S)-{{(benzyloxy)carbonyl}amino}-4-phenylbutyric acid benzyl ester (from step A) (10.97 g, 27.2 mmol) in MeOH (1 L) was stirred at room temperature for 7 h under an hydrogen atmosphere (1 atmosphere) in the presence of 20% Pd (OH)2/C (50 mg). The catalyst was removed by filtration through diatomaceous earth. The filtrate was concentrated under reduced pressure to yield 4.53 g (93% yield) of 3(S)-amino-4-phenylbutyric acid as a white solid. A suspension of NaHCO3 (12.74 g, 152 mmol) in MeCN (1.55 L) was stirred and heated to gentle reflux. Mesyl chloride (2.15 mL, 27.8 mmol) was added, followed by the portionwise addition of the preceding acid (4.53 g, 25.3 mmol) over 5 h. After 16 h under reflux, the solid was removed by filtration at 60° and the filtrate was concentrated under reduced pressure. The residual solid was triturated with EtOAc and filtered. The filtrate was concentrated and the residue purified by flash chromatography (SiO2, 40% EtOAc in hexane) to give 4(S)-benzylazetidin-2-one (2.20 g, 54% yield) as a white solid. 1H-NMR (400 MHz, CDCl3) δ7.35-7.17 (m, 5H), 5.83 (brs, 1H), 3.88-3.82 (m, 1H), 3.08 (ddd, J=14.8, 5.0, 2.2 Hz, 1H), 2.98 (dd, J=13.7, 5.7 Hz, 1H), 2.84 (dd, J=13.7, 7.9 Hz, 1H), 2.70 (ddd, J=14.9, 2.0, 1.3 Hz, 1H).

Provenance & Evidence