Reaktion #465130

Reaktionsgleichung

3-benzoylpropionic acid

triethylamine

2-methyl-2-propanol

→

t-butyl 3-benzoylpropionate

Ausbeute 64.0%

Lösungsmittel

benzene

Reaktionsbedingungen

Aufarbeitung

1. 1
   Filtrationafter which the THF solution was filtered
2. 2
   Sonstigeto remove the triethylamine hydrochloride
3. 3
   Sonstigeto yield a light beige solid
4. 4
   workup.STIRRINGthe mixture was stirred
5. 5
   Temperaturwith heating
6. 6
   workup.DISSOLUTIONto dissolve all of the solid
7. 7
   workup.ADDITIONwas added to the solution
8. 8
   workup.STIRRINGThe solution immediately turned dark red and was stirred at room temperature for 36 hours
9. 9
   WaschenThe solution was washed with 10% aqueous HCl solution
10. 10
    TrocknenThe organic layer was then dried (MgSO4)
11. 11
    Filtrationfiltered
12. 12
    Einengenconcentrated
13. 13
    SonstigeThe resultant oil was purified twice by column chromatography (silica gel, Eluent: 20% ethyl acetate: hexanes)
14. 14
    Sonstigethe resultant oil obtained
15. 15
    workup.DISTILLATIONwas distilled under reduced pressure

Vorschrift

Once the 3-benzoylpropionic acid had dissolved, then 6.1 mL (0.0830 mol) of triethylamine was added. The solution was stirred for 6 hours, after which the THF solution was filtered to remove the triethylamine hydrochloride. The filtrate was rotoevaporated to yield a light beige solid. To this solid was added 200 mL of benzene followed by 6.0 mL (0.104 mol) of 2-methyl-2-propanol and the mixture was stirred with heating to dissolve all of the solid. After complete dissolution, 5.40 g (0.0442 mol) of DMAP was added to the solution. The solution immediately turned dark red and was stirred at room temperature for 36 hours. The solution was washed with 10% aqueous HCl solution, followed by 2×5% aq. NaOH solution and finally with water. The organic layer was then dried (MgSO4), filtered and concentrated. The resultant oil was purified twice by column chromatography (silica gel, Eluent: 20% ethyl acetate: hexanes) and the resultant oil obtained was distilled under reduced pressure to yield 6.45 g (64%) of t-butyl 3-benzoylpropionate as a colorless oil. lit bp 129-130° C. at 1.5 mm Hg.; 1HNMR ppm (δ), CDCL3 7.98 (d, 2H), 7.54 (m, 1H), 7.46 (m, 2H), 3.26 (t, 2H), 2.68 (t, 2H), 1.45 (s, 9H). 13CNMR ppm (δ), CDCl3, 198.3 (C=O), 172.1 (CO2), 136.7 (q), 133.0, 128.6, 128.0, 80.6 (C(CH3)3), 33.5, 29.4, 28.0 (CH3).

Quelle