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ChemicalBook CAS DataBase List Cbz-L-tert-Leucine
62965-10-0

Cbz-L-tert-Leucine synthesis

8synthesis methods
N-(Benzyloxycarbonyloxy)succinimide

13139-17-8

L-tert-Leucine

20859-02-3

Cbz-L-tert-Leucine

62965-10-0

Step A: Synthesis of (S)-2-(((benzyloxy)carbonyl)amino)-3,3-dimethylbutanoic acid; to a methanolic (200 mL) suspension of L-tert-leucine (11.88 g, 90.7 mmol) was sequentially added triethylamine (26.56 mL, 190 mmol) and N-(benzyloxycarbonyloxy)succinimide (24.88 g, 99.8 mmol). The reaction mixture was stirred at room temperature for 14 hours. After completion of the reaction, methanol was removed by rotary evaporator under reduced pressure to give a viscous light yellow oil. The oily substance was dissolved in ethyl acetate (100 mL) and the organic layer was washed sequentially with 1 M hydrochloric acid (15 mL) and saturated saline. The organic layer was dried over anhydrous magnesium sulfate and filtered, and the filtrate was concentrated under reduced pressure by rotary evaporator to afford the title compound (S)-2-(((benzyloxy)carbonyl)amino)-3,3-dimethylbutanoic acid as an oil (24 g, quantitative yield).1H-NMR (CDCl3) δ: 7.43-7.36 (5H, m), 5.36 (1H, d, J = 9.4 Hz) , 5.12 (2H, br s), 4.20 (1H, d, J = 9.6 Hz), 1.02 (9H, s).LRMS: m/z 266 [M + H]+, 264 [M - H]-, 529 [2M - H]-.

-

Yield: 100%

Reaction Conditions:

with triethylamine in methanol at 20; for 14 h;

Steps:

A
Step A: 2S-Benzyloxycarbonylamino-3,3-dimethyl-butyric acid; To a suspension of L-tert-leucine (11.88 g, 90.7 mmol) in methanol (200 ml) were added triethylamine (26.56 ml, 190 mmol) and N-(benzyloxycarbonyl- oxy)-succinimide (24.88 g, 99.8 mmol). The reaction mixture was stirred at room temperature for 14 h. Methanol was removed in vacuo to afford a viscous pale yellow oil, which was dissolved in ethyl acetate (100 ml). The organic layer was washed with 1M hydrochloric acid (15 ml) and brine, dried over anhydrous magnesium sulfate and filtered. The solvent was removed in vacuo to fumish the title compound as an oil (24 g, quant.). 1H-NMR; δ(CDCl3), 7.43-7.36 (5H, m), 5.36 (1H, d, J = 9.4 Hz), 5.12 (2H, br s), 4.20 (1H, d, J = 9.6 Hz) and 1.02 (9H, s). LRMS: +ve ion 266 [M+H], -ve ion 264 [M-H], 529 [2M-H].

References:

Vernalis (Oxford) Ltd EP1210330, 2005, B1 Location in patent:Page/Page column 9-10

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