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

HRID 1802383Notes

Reaction equation

HRID 1802383 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 62 g (0.32 mol) of ethyl α-bromoisobutyrate in DMF (500 mL) at room temperature are added 72 g (0.63 mol) of potassium thioacetate. The reaction is stirred for 16 h and then concentrated under reduced pressure. The residue is diluted with a 2M aqueous hydrochloric acid 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 of the residue by column chromatography (silica, eluent heptanes, DCM) provides 44 g of 2-acetylsulfanyl-2-methyl-propionic acid ethyl ester. Yield: 73%; ES-MS: m/z 191 [M+H]; 1H NMR (400 MHz, CHLOROFORM-d) δ ppm 1.27 (3 H, t, J=7.09 Hz), 1.58 (6 H, s), 2.28 (3 H, s), 4.20 (2 H, q, J=7.09 Hz)

Workup

  1. concentrationconcentrated under reduced pressure
  2. additionThe residue is diluted with a 2M aqueous hydrochloric acid 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 of the residue by column chromatography (silica, eluent heptanes, DCM)

Sources & evidence

ORD record
ord-8e33cd869a9041799f86a8b4715de877
Source dataset
uspto-grants-2013_01
Patent number
US08349871B2

Reaction notes

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