Reaktion #48459

Reaktionsgleichung

2-bromopropanoic acid

carbon disulfide

benzylmagnesium chloride

ether

→

title compound ( 20 )

Ausbeute 39.0%

2-[(2-phenylethanethioyl)sulfanyl]propanoic Acid

Ausbeute 39.0%

Lösungsmittel

ethyl acetate

tetrahydrofuran

Reaktionsbedingungen

Aufarbeitung

1. 1
   workup.WAITAfter 48 h
2. 2
   Waschenwashed with water (3×100 mL)
3. 3
   TrocknenThe organic layer was dried (magnesium sulfate)
4. 4
   Sonstigeevaporated
5. 5
   workup.DISTILLATIONThe remaining liquid was distilled (120°/0.13 Pa, Kugelrohr)
6. 6
   Sonstigeto remove unreacted 2-bromopropanoic acid
7. 7
   workup.DISSOLUTIONThe residue was then dissolved in ether (200 mL)
8. 8
   Extraktionextracted with 5% sodium bicarbonate solution (4×50 mL)
9. 9
   WaschenThe combined aqueous extracts were washed with ether (100 mL)
10. 10
    ExtraktionThe resulting mixture was extracted with ethyl acetate (2×100 mL)
11. 11
    Waschenthe combined organic extracts were washed with water (2×50 mL), saturated sodium chloride (50 mL)
12. 12
    Trocknendried with magnesium sulfate
13. 13
    SonstigeEvaporation of the solvent

Vorschrift

A solution of benzylmagnesium chloride in ether (1.0 M, 40 mL, 40 mmol) was added slowly with stirring to an ice-cooled solution of carbon disulfide (4.0 mL, 66 mmol) in dry tetrahydrofuran (40 mL) under nitrogen. After 30 min, 2-bromopropanoic acid (3.6 mL, 6.2 g, 40 mmol) was added and the reaction was stirred at ambient temperature. After 48 h, the mixture was poured into ethyl acetate (200 mL) and washed with water (3×100 mL), followed by saturated sodium chloride solution (100 mL). The organic layer was dried (magnesium sulfate) and evaporated. The remaining liquid was distilled (120°/0.13 Pa, Kugelrohr) to remove unreacted 2-bromopropanoic acid. The residue was then dissolved in ether (200 mL) and extracted with 5% sodium bicarbonate solution (4×50 mL). The combined aqueous extracts were washed with ether (100 mL), then acidified to pH<1 with 2 M hydrochloric acid. The resulting mixture was extracted with ethyl acetate (2×100 mL) and the combined organic extracts were washed with water (2×50 mL), saturated sodium chloride (50 mL) and then dried with magnesium sulfate. Evaporation of the solvent gave the title compound (20) as a red liquid (3.73 g, 39%) which slowly solidified on standing.

Quelle