Ethyl chloroformate → HCID 54283045, compound

HRID 1279087Notes

Reaction equation

HRID 1279087 reaction equation
[NH2:1][C@@H:2]([C:6]([S:9][CH:10]([CH3:12])[CH3:11])([CH3:8])[CH3:7])[C:3]([OH:5])=[O:4].O1CCOCC1.[OH-].[Na+].Cl[C:22]([O:24][CH2:25][CH3:26])=[O:23]>O>[CH2:25]([O:24][C:22]([NH:1][C@@H:2]([C:6]([S:9][CH:10]([CH3:12])[CH3:11])([CH3:7])[CH3:8])[C:3]([OH:5])=[O:4])=[O:23])[CH3:26]

Participants

6

Reactant 4

HCID 10928Ethyl chloroformateHCID 14798Sodium Hydroxide3×HCID 312751,4-DioxaneHCID 22958551HCID 22958551, compound

Product 1

HCID 54283045HCID 54283045, compoundYield 21%

Reagents, catalysts & solvents 1

HCID 962WaterSolvent

Procedure

2-(R)-Amino-3-isopropylsulfanyl-3-methyl-butyric acid (approx. 27 mmol; crude material from the previous step) was dissolved in 40 mL of water and 40 mL of dioxane and pH 9.5 was adjusted by adding aqueous NaOH. Ethyl chloroformate (3.3 mL) was slowly added at 5° C. while maintaining pH 9.5 by addition of the appropriate amount of aqueous NaOH. Stirring was continued for 6 h at room temperature. Aqueous NaOH was added (pH 11) and the dioxane removed in vacuo followed by extraction of the remaining aqueous solution with ethyl acetate. KHSO4 was added and the acidified aqueous solution extracted with ethyl acetate several times. Evaporation of the solvent in vacuo gave a yellow oil, which was purified by HPLC (RP-18; pH 2.3; H2O/CH3OH 3/7) to give 1.50 g (21%) of the title compound as a colorless oil. (+)-APCI-MS: 264 (MH−).

Workup

  1. temperaturewhile maintaining pH 9.5
  2. customthe dioxane removed in vacuo
  3. extractionfollowed by extraction of the remaining aqueous solution with ethyl acetate
  4. additionKHSO4 was added
  5. extractionthe acidified aqueous solution extracted with ethyl acetate several times
  6. customEvaporation of the solvent in vacuo
  7. customgave a yellow oil, which
  8. customwas purified by HPLC (RP-18; pH 2.3; H2O/CH3OH 3/7)

Sources & evidence

ORD record
ord-c82a28701085434c9f225d51232fe8be
Source dataset
uspto-grants-2002_09
Patent number
US06444672B1

Reaction notes

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