Boc-L-alanine methyl ester → tert-butyl N-((2S)-1-oxopropan-2-yl)carbamate

Boc-L-alanine methyl ester (5.0 g, 24.6 mmol) was dissolved in dry toluene (150 ml) under an argon atmosphere and cooled in a dry ice-acetone bath. To this vigorously stirred solution was added a solution of diisobutylaluminumhydride (1.0 M in hexanes, 61.5 ml, 61.5 mmol), pre-cooled in a dry ice-acetone bath, via a transfer needle. After 6 minutes, the reaction was carefully quenched with methanol (4 ml) and the mixture allowed to warm to room temperature. The reaction mixture was poured into a separatory funnel containing 250 ml ether and 200 ml of ice cold 0.25 N hydrochloric acid. The layers were separated and the organic layer was washed with 0.25 N hydrochloric acid (3×80 ml) and brine (50 ml). The organic layer was dried over magnesium sulfate, filtered and concentrated using a rotary evaporator at ambient temperature. The residue was chromatographed using hexanes--30% ethyl-acetate to give Boc-L-alaninal. The compound may also be prepared by the technique described in Synthesis, 1983, pg. 676.

1. temperaturecooled in a dry ice-acetone bath
2. temperaturepre-cooled in a dry ice-acetone bath, via a transfer needle
3. customthe reaction was carefully quenched with methanol (4 ml)
4. additionThe reaction mixture was poured into a separatory funnel
5. additioncontaining 250 ml ether and 200 ml of ice cold 0.25 N hydrochloric acid
6. customThe layers were separated
7. washthe organic layer was washed with 0.25 N hydrochloric acid (3×80 ml) and brine (50 ml)
8. dry with materialThe organic layer was dried over magnesium sulfate
9. filtrationfiltered
10. concentrationconcentrated
11. customa rotary evaporator at ambient temperature
12. customThe residue was chromatographed

ORD record

ord-4b0625eccb9b43b1b544250f32bc1e4b

Source dataset

uspto-grants-2000_10

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06130315