Methyl chloroformate → HCID 58209574, compound

HRID 68273Notes

Reaction equation

HRID 68273 reaction equation
CCN(C(C)C)C(C)C.Cl.[NH2:11][C@@H:12]([CH:20]([CH3:22])[CH3:21])[C:13]([O:15][C:16]([CH3:19])([CH3:18])[CH3:17])=[O:14].Cl[C:24]([O:26][CH3:27])=[O:25]>C1COCC1>[CH3:27][O:26][C:24]([NH:11][C@@H:12]([CH:20]([CH3:22])[CH3:21])[C:13]([O:15][C:16]([CH3:17])([CH3:19])[CH3:18])=[O:14])=[O:25]

Participants

5

Reactant 3

HCID 6586Methyl chloroformateHCID 81531DiisopropylethylamineHCID 12490702tert-butyl (2S)-2-amino-3-methylbutanoate hydrochloride

Product 1

HCID 58209574HCID 58209574, compoundYield 99.3%

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent

Procedure

DIEA (137.5 mL, 0.766 mol) was added to a suspension of (S)-tert-butyl 2-amino-3-methylbutanoate hydrochloride (75.0 g, 0.357 mol) in THF (900 mL), and the mixture was cooled to 0° C. (ice/water bath). Methyl chloroformate (29.0 mL, 0.375 mol) was added dropwise over 45 min, the cooling bath was removed and the heterogeneous mixture was stirred at ambient temperature for 3 h. The solvent was removed under diminished pressure and the residue partitioned between EtOAc and water (1 L each). The organic layer was washed with H2O (1 L) and brine (1 L), dried (MgSO4), filtered and concentrated under diminished pressure. The crude material was passed through a plug of silica gel (1 kg), eluting with hexanes (4 L) and 15:85 EtOAc/hexanes (4 L) to afford (S)-tert-butyl 2-(methoxycarbonylamino)-3-methylbutanoate as a clear oil (82.0 g, 99% yield). 1H-NMR (500 MHz, DMSO-d6, δ=2.5 ppm) 7.34 (d, J=8.6, 1H), 3.77 (dd, J=8.6, 6.1, 1H), 3.53 (s, 3H), 1.94-2.05 (m, 1H), 1.39 (s, 9H), 0.83-0.92 (m, 6H). 13C-NMR (126 MHz, DMSO-d6, δ=39.2 ppm) 170.92, 156.84, 80.38, 60.00, 51.34, 29.76, 27.62, 18.92, 17.95. LC/MS: [M+Na]+ 254.17.

Workup

  1. customthe cooling bath was removed
  2. customThe solvent was removed under diminished pressure
  3. customthe residue partitioned between EtOAc and water (1 L each)
  4. washThe organic layer was washed with H2O (1 L) and brine (1 L)
  5. dry with materialdried (MgSO4)
  6. filtrationfiltered
  7. concentrationconcentrated under diminished pressure
  8. washeluting with hexanes (4 L) and 15:85 EtOAc/hexanes (4 L)

Sources & evidence

ORD record
ord-aac8ecdc60284f21b6c9437646022edb
Source dataset
uspto-grants-2014_09
Patent number
US08822444B2

Reaction notes

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