Hydrochloric Acid → 2,2-Dimethyl-3-phenylpropanoic acid

Temperatur

0 °C

Hexamethyldisilazane (34 g, 0.21 mol) was dissolved in tetrahydrofuran (280 mL), and 1.67M n-butyllithium in hexane (127 mL, 0.21 mol) was added dropwise at −78° C. The reaction solution was warmed to 0° C. over 1 hour and then cooled to −78° C. again. Benzyl isobutyrate (25 g, 0.14 mol) in tetrahydrofuran (70 mL) was added dropwise, and the reaction solution was stirred at −78° C. for 1 hour. Chlorotrimethylsilane (36 mL, 0.12 mol) was further added dropwise at the same temperature, and the reaction solution was stirred for 1 hour, then warmed to room temperature and stirred for 19 hours. After completion of the reaction, the solvent was partially removed from the reaction solution under reduced pressure, and the resulting white suspension was diluted with hexane (200 mL) and filtered through Celite under a nitrogen atmosphere to remove the white solid from the reaction solution. The filtrate was distiled under reduced pressure, and the resulting pale yellow oil was heated at 100° C. for 2 hours to give a brown oil. The brown oil was mixed with 10 mL of 1 M hydrochloric acid and stirred at 60° C. for 4 hours, neutralized with saturated aqueous sodium hydrogen carbonate and extracted with ethyl acetate (100 mL×2) and chloroform (100 mL×2). The resulting organic layer was concentrated, and the resulting residue was purified by intermediate pressure silica gel column chromatography (silica gel 80 g, ethyl acetate 100%) to give 8.41 g of the desired product as white crystals.

1. temperaturecooled to −78° C. again
2. stirringthe reaction solution was stirred for 1 hour
3. temperaturewarmed to room temperature
4. stirringstirred for 19 hours
5. customAfter completion of the reaction
6. customthe solvent was partially removed from the reaction solution under reduced pressure
7. additionthe resulting white suspension was diluted with hexane (200 mL)
8. filtrationfiltered through Celite under a nitrogen atmosphere
9. customto remove the white solid from the reaction solution
10. customThe filtrate was distiled under reduced pressure
11. temperaturethe resulting pale yellow oil was heated at 100° C. for 2 hours
12. customto give a brown oil
13. stirringstirred at 60° C. for 4 hours
14. extractionextracted with ethyl acetate (100 mL×2) and chloroform (100 mL×2)
15. concentrationThe resulting organic layer was concentrated
16. customthe resulting residue was purified by intermediate pressure silica gel column chromatography (silica gel 80 g, ethyl acetate 100%)

ORD-Eintrag

ord-5eb09215b94f421c90eb9bc32fff0903

Quelldatensatz

uspto-grants-2014_02

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US08658686B2