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

ORD record

ord-33affe05117547ec85da035c24e8106f

Source dataset

uspto-grants-2001_05

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06232342B1