Hydrochloric Acid → HCID 20586035, compound

Temperature

0 °C

L-leucine methyl ester hydrochloride (25 g, 0.14 mol) was dissolved in methylene chloride (450 mL), cooled to 0° C., and pyridine (43.5 g, 0.55 mol, 44.5 mL) was added, then a 1.93 M solution of phosgene in toluene (0.18 mol, 92.7 mL) was added slowly. After stirring at 0° C. for 2 h, the mixture was poured into 0.5 N HCl (1400 mL) and ice (900 mL). The organic layer was washed with 0.5 N HCl (1400 mL) and ice (900 mL). The aqueous layers were extracted with methylene chloride (450 mL) and the combined organic layers were washed with saturated brine (1400 mL) and ice (900 mL), then dried (MgSO4), filtered and concentrated. The residue was distilled (56-58° C.; 0.78 mmHg) to provide the title compound as a colorless liquid (20.4 g, 86%). 1H NMR (250 MHz, CDCl3) δ 4.04 (dd, 1H), 3.82 (s, 3H), 1.92-1.72 (m, 1H), 1.69-1.62 (m, 2H), 0.96 (d, 3H), 0.94 (d, 3H).

1. washThe organic layer was washed with 0.5 N HCl (1400 mL) and ice (900 mL)
2. extractionThe aqueous layers were extracted with methylene chloride (450 mL)
3. washthe combined organic layers were washed with saturated brine (1400 mL) and ice (900 mL)
4. dry with materialdried (MgSO4)
5. filtrationfiltered
6. concentrationconcentrated
7. distillationThe residue was distilled (56-58° C.; 0.78 mmHg)

ORD record

ord-f684681cb99c4b8a8884a8d0de4ed4cb

Source dataset

uspto-grants-2003_05

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06562842B2