D-Phenylalanine → (R)-2-Bromo-3-phenylpropionic acid

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

Potassium bromide (24.49 g, 0.21 moles) was first dissolved in a 2.50 N aqueous solution of sulfuric acid (120 mL). To this stirring solution was then added D-phenylalanine (10.00 g, 60.54 mmoles). After the addition, the mixture was cooled down to 0° C. and sodium nitrite (6.27 g., 90.87 mmoles) was added in small portions during 30 minutes. A strong bubbling was observed. The reaction was kept at this temperature for 50 minutes, and it was then allowed to proceed at room temperature for another 60 minutes. The crude product was isolated using standard work up and the obtained residue was purified by flash chromatography (SiO2, 30% ethyl acetate-70% hexanes) to give 7.20 g (51.9% yield) of the title compound as a yellowish oil: 1H NMR (CDCl3, 300 MHz) □ 10.86 (br s, 1H), 7.31 (m, 5H), 4.48 (t, 1H), 3.51 (dd, 1H), 3.29 (dd, 1H); 13C NMR (CDCl3, 75 MHz) □175.29, 136.26, 129.10, 128.69, 127.42, 44.83, 40.62.

Herkunft & Nachweise