Water → 4-Tert-butoxycarbonylamino-4-cyclohexyl-but-2-enoic acid methyl ester

To an ice cooled solution of trimethyl phosphonoacetate (19 mL, 0.11 mol) in THF (200 mL) was added 60% NaH (3.1 g, 0.08 mol) in portions. The ice bath was removed and the reaction mixture was stirred at room temperature for 30 min. The reaction mixture was then cooled to 0° C. before a solution of (1-cyclohexyl-2-oxo-ethyl)-carbamic acid tert-butyl ester (9 g, 37 mmol) in THF (200 mL) was added. The reaction mixture was stirred at room temperature for another 20 min. Water (100 mL) was added, and then most of the THF was evaporated. The product was extracted with EtOAc (400 mL), and the organic layer was washed with aqueous NaCl solution and then dried with MgSO4. Evaporation yielded a residue which was purified by column chromatography (1:1 heptane:EtOAc) to yield 4-tert-butoxycarbonylamino-4-cyclohexyl-but-2-enoic acid methyl ester as a white solid.

1. customThe ice bath was removed
2. additionwas added
3. stirringThe reaction mixture was stirred at room temperature for another 20 min
4. custommost of the THF was evaporated
5. extractionThe product was extracted with EtOAc (400 mL)
6. washthe organic layer was washed with aqueous NaCl solution
7. dry with materialdried with MgSO4
8. customEvaporation
9. customyielded a residue which
10. customwas purified by column chromatography (1:1 heptane:EtOAc)

ORD-Eintrag

ord-9cb01b08a3ec4aa69db13fe5993441bb

Quelldatensatz

uspto-grants-2009_05

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US07531545B2