L-Leucine → L-Leucine, N-((1,1-dimethylethoxy)carbonyl)-

Temperature

23 °C

To the suspension of 10 g (76.2 mmol ) of L-leucine in 140 mL of diethyl ether was added 80 mL of 10% NaOH. After all solid dissolves, 20 mL (87.1 mmol) of BOC2O was added to the reaction mixture. The resulting reaction mixture was stirred at 23° C. for 12 h. After this period, the layers were separated and the aqueous layer was acidified to pH 1 by careful addition of 1 N aqueous HCl at 0° C. The resulting mixture was extracted with ethyl acetate (3×100 mL). The organic layers were combined and washed with brine and dried over anhydrous Na2SO4. The solvent was removed under reduced pressure to provide title product which was used directly for next reaction without further purification (yield, 97%). 1H NMR (400 MHz, CDCl3) δ 4.89 (broad d, 1H, J=8.3 Hz), 4.31 (m, 1H), 1.74–1.49 (m, 3H), 1.44 (s, 9H), 0.95 (d, 6H, J=6.5 Hz).

1. dissolutionAfter all solid dissolves
2. customThe resulting reaction mixture
3. waitAfter this period
4. customthe layers were separated
5. additionthe aqueous layer was acidified to pH 1 by careful addition of 1 N aqueous HCl at 0° C
6. extractionThe resulting mixture was extracted with ethyl acetate (3×100 mL)
7. washwashed with brine
8. dry with materialdried over anhydrous Na2SO4
9. customThe solvent was removed under reduced pressure

ORD record

ord-fa3dd99ca5c7443d92be56970ea8dc1f

Source dataset

uspto-grants-2007_07

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07244708B2