Reaktion #82510

Reaktionsgleichung

chloromethylphenyl sulfide

isobutyric acid

n-butyllithium

sodium hydride

diisopropylamine

→

2,2-dimethyl-3-(thiophenyl)propionic acid

Ausbeute 21.6%

Lösungsmittel

diethyl ether

hexane

tetrahydrofuran

water

Reaktionsbedingungen

Aufarbeitung

1. 1
   TemperaturAfter heating
2. 2
   Temperaturat reflux for 15 min
3. 3
   Temperaturthe solution was heated to 35° C. for 30 min
4. 4
   Temperaturcooled to 0° C.
5. 5
   workup.WAITAfter 30 min at 0° C.
6. 6
   workup.WAIT35° C. for 1 hour
7. 7
   Sonstigewas recooled to 0° C.
8. 8
   SonstigeThe water layer was separated
9. 9
   Extraktionextracted with diethyl ether
10. 10
    Sonstigedried
11. 11
    Einengenconcentrated
12. 12
    Sonstigeto afford 4.23 g of crude product
13. 13
    SonstigeRecrystallization from methylene chloride/hexane

Vorschrift

To a mixture of 1.23 g (41 mmol) of 80% sodium hydride in 50 mL of dry tetrahydrofuran was added 3.88 g (38.3 mmol) of diisopropylamine and then 3.3 g (37.5 mmol) of isobutyric acid. After heating at reflux for 15 min, and cooling to 0° C., 15 mL (37.5 mmol) of a 2.5M n-butyllithium in hexane solution was added over 10 min. After 15 min, the solution was heated to 35° C. for 30 min, cooled to 0° C. and 5.94 g (37.5 mmol) of chloromethylphenyl sulfide was added. After 30 min at 0° C. and 35° C. for 1 hour, the solution was recooled to 0° C., water added and then diethyl ether. The water layer was separated, acidified and extracted with diethyl ether, dried and concentrated to afford 4.23 g of crude product. Recrystallization from methylene chloride/hexane afforded 1.49 g of 2,2-dimethyl-3-(thiophenyl)propionic acid, m/e 211 (M+H). To a mixture of 1.1 g (5.2 mmol) of 2,2-dimethyl-3-(thiophenyl)propionic acid in 12 mL of acetic acid was added 1.8 mL (17.8 mmol) of 30% aqueous hydrogen peroxide. After 10 minutes at room temperature, all the solids dissolved and the solution was heated to reflux for two hours. After cooling in an ice bath, 23 mL of 10% aqueous sodium sulfite was added and the volatiles removed under vacuum. The residue was acidified with 12N aqueous HCl, extracted with ethyl acetate, dried and concentrated to afford 1.23 g of 2,2-dimethyl-3-(phenylsulfonyl)propionic acid, m/e 260 (M+NH4 +).

Quelle