Propanoic acid, 2-bromo-2-methyl-, ethyl ester → Ethyl 2-(acetylthio)-2-methylpropanoate

HRID 386857Notes

Reaction equation

HRID 386857 reaction equation
Br[C:2]([CH3:9])([CH3:8])[C:3]([O:5][CH2:6][CH3:7])=[O:4].[C:10]([O-:13])(=[S:12])[CH3:11].[K+]>CN(C=O)C>[CH2:6]([O:5][C:3](=[O:4])[C:2]([S:12][C:10](=[O:13])[CH3:11])([CH3:9])[CH3:8])[CH3:7]

Participants

4

Reactant 2

HCID 11745Propanoic acid, 2-bromo-2-methyl-, ethyl esterHCID 23670855Potassium ethanethioate

Product 1

HCID 57937863Ethyl 2-(acetylthio)-2-methylpropanoateYield 73%

Reagents, catalysts & solvents 1

HCID 6228DimethylformamideSolvent

Procedure

To a solution of ethyl α-bromoisobutyrate (62 g, 0.32 mol) in DMF (500 mL) at room temperature is added potassium thioacetate (72 g, 0.63 mol). The reaction is stirred for 16 h and then concentrated under reduced pressure. The residue is diluted with a 2M aqueous HCl solution (500 mL) and extracted with ethyl acetate (3×500 mL). The organic fractions are combined, washed with brine (300 mL), dried over MgSO4, filtered and concentrated under reduced pressure. Purification by chromatography on silica eluting with heptanes/DCM provides 44 g of 2-acetylsulfanyl-2-methyl-propionic acid ethyl ester. Yield: 73%; m/z 191 [M+H]; 1H NMR (250 MHz, CHLOROFORM-d) δ ppm 1.18-1.30 (3H, m), 1.57 (6H, s), 2.27 (3H, s), 4.19 (2H, q, J=7.16 Hz)

Workup

  1. concentrationconcentrated under reduced pressure
  2. additionThe residue is diluted with a 2M aqueous HCl solution (500 mL)
  3. extractionextracted with ethyl acetate (3×500 mL)
  4. washwashed with brine (300 mL)
  5. dry with materialdried over MgSO4
  6. filtrationfiltered
  7. concentrationconcentrated under reduced pressure
  8. customPurification by chromatography on silica eluting with heptanes/DCM

Sources & evidence

ORD record
ord-163b5cf2d241408291819ccda6ab5476
Source dataset
uspto-grants-2013_02
Patent number
US08372874B2

Reaction notes

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