Ethyl Acetate → D-2-Amino-5-phenyl-pentanoic acid

To a stirred solution of N-[(1,1-dimethylethoxy)carbonyl]amino-(2S,3R)-(+)-6-oxo-2,3-diphenyl-4-morpholinecarboxylate, (1.0 g, 2.8 mmol) and cinnamyl bromide (2.78 g, 14 mmol) in dry THF (70 mL) at -78° C., was added dropwise sodium hexamethyldisilazide (5.6 mL; 1.0M solution in hexane). The reaction mixture was stirred for 30 minutes, then poured into ethyl acetate (150 mL) and washed with brine, dried over anhydrous magnesium sulfate, filtered and evaporated. The crude product was first washed with warm hexane and then with an ether:hexane (1:1) mixture. The solid material was the desired product. A solution of this intermediate (1.0 g, 2.1 mmol) in CH2Cl2 (2 mL) and TFA (2 mL) was stirred at room temperature for 1 h. The solvents were removed under reduced pressure and the residue was dissolved in saturated aqueous sodium bicarbonate solution and extracted with CHCl3. The organic layer was washed with brine, dried over potassium carbonate, filtered and evaporated to give the amine as a foam which was used without purification. Approximately 0.6 g (1.62 mmol) of this material was dissolved in 40 mL of (2:1) EtOH:THF and hydrogenated under 40 psi using PdCl2 /C for 24 h. The catalyst was filtered off through celite pad and the solvent was evaporated to give the title compound as a colorless solid.

1. washwashed with brine
2. dry with materialdried over anhydrous magnesium sulfate
3. filtrationfiltered
4. customevaporated
5. washThe crude product was first washed with warm hexane
6. customThe solvents were removed under reduced pressure
7. dissolutionthe residue was dissolved in saturated aqueous sodium bicarbonate solution
8. extractionextracted with CHCl3
9. washThe organic layer was washed with brine
10. dry with materialdried over potassium carbonate
11. filtrationfiltered
12. customevaporated

ORD record

ord-e21331dd2bbb42f4933741f02dcd021c

Source dataset

uspto-grants-1996_11

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US05578593