Isobutyric Acid → 2,2-Dimethyl-3-(thiophen-2-yl)propanoic acid

Temperatur

0 °C

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).

1. temperatureAfter heating
2. temperatureat reflux for 15 min
3. temperaturethe solution was heated to 35° C. for 30 min
4. temperaturecooled to 0° C.
5. waitAfter 30 min at 0° C.
6. wait35° C. for 1 hour
7. customwas recooled to 0° C.
8. customThe water layer was separated
9. extractionextracted with diethyl ether
10. customdried
11. concentrationconcentrated
12. customto afford 4.23 g of crude product
13. customRecrystallization from methylene chloride/hexane

ORD-Eintrag

ord-950ecf4497bd4b84b4dc009a3ce5fbd3

Quelldatensatz

uspto-grants-1997_04

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US05620977