Triethylamine → HCID 86678442, compound

Temperature

0 °C

To a solution of (S)-5-tert-butoxy-4-(tert-butoxycarbonylamino)-5-oxopentanoic acid (1.0 g, 3.3 mmol) in anhydrous CH2Cl2 (15 mL) was added triethylamine (0.69 mL, 4.95 mmol) and cooled the mixture to 0° C. with an external ice-methanol cold bath. At the same temperature, 4-dimethylaminopyridine (0.04 g, 0.33 mmol) followed by ethyl chloroformate (0.38 mL, 3.96 mmol) were added sequentially and the mixture stirred for one hour. After completion of the reaction, reaction mixture was diluted with CH2Cl2 (150 mL) and the saturated aq. NaHCO3 solution (150 mL). The layers were separated and the aqueous phase extracted with an additional CH2Cl2 (100 mL). The combined organic layers were dried over Na2SO4, filtered and the filtrate was concentrated under reduced pressure. The resulting residue was purified on 40 g silica gel column (eluent hexanes to 30% ethyl acetate in hexanes) to afford (S)-1-tert-butyl 5-ethyl 2-(tert-butoxycarbonylamino)pentanedioate (0.80 g, 73% yield) as a thick oil. 1H NMR (CDCl3) δ ppm: 5.10 (d, J=7.8 Hz, 1H), 4.16 (m, 3H), 2.39 (m, 2H), 2.16 (m, 1H), 1.94 (m, 1H), 1.49 (s, 9H), 1.46 (s, 9H), 1.28 (t, J=7.2 Hz, 3H). MS (ESI+): 354 (M+Na)+.

1. additionwere added sequentially
2. customAfter completion of the reaction, reaction mixture
3. customThe layers were separated
4. extractionthe aqueous phase extracted with an additional CH2Cl2 (100 mL)
5. dry with materialThe combined organic layers were dried over Na2SO4
6. filtrationfiltered
7. concentrationthe filtrate was concentrated under reduced pressure
8. customThe resulting residue was purified on 40 g silica gel column (eluent hexanes to 30% ethyl acetate in hexanes)

ORD record

ord-159a8c75626c43ae9236402a7eca36ad

Source dataset

uspto-grants-2014_07

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08784774B2