Reaktion #79373

Reaktionsgleichung

5-Bromo-2,2-dimethyl-pentanoic acid ethyl ester

ethylene glycol

NaI

NaH

→

desired product

Ausbeute 20.0%

5-(2-Hydroxy-ethoxy)-2,2-dimethyl-pentanoic acid ethyl ester

Ausbeute 20.0%

Lösungsmittel

H2O

Reaktionsbedingungen

Aufarbeitung

1. 1
   workup.STIRRINGAfter stirring for 20 min at rt
2. 2
   Temperaturthe mixture was cooled to rt
3. 3
   Extraktionextracted with chloroform (5′ 100 mL)
4. 4
   ExtraktionThe chloroform extract
5. 5
   Waschenwas then washed with 10% aq Na2S2O3 (300 mL)
6. 6
   TrocknenAfter drying over MgSO4
7. 7
   Sonstigethe solvent was evaporated
8. 8
   Sonstigeto give crude product (13.1 g), which
9. 9
   workup.DISTILLATIONwas further purified by vacuum distillation (80-83 C., 0.11 torr)

Vorschrift

5-Bromo-2,2-dimethyl-pentanoic acid ethyl ester LVX (19 g, 74.5 mmol) was dissolved in ethylene glycol LXVI (150 mL) and stirred under argon. After NaI (1.13 g, 7.5 mmol) was added as a catalyst, NaH as a dispersion in mineral oil (3.0 g, 60%, in mineral oil; 75 mmol) was added slowly in five portions. After stirring for 20 min at rt, the mixture was subjected to gentle heating in an oil-bath to 70° C. After 20 h, the heating was discontinued and the mixture was cooled to rt. The reaction mixture was diluted with H2O (500 mL), then extracted with chloroform (5′ 100 mL). The chloroform extract was then washed with 10% aq Na2S2O3 (300 mL), then with H2O (400 mL). After drying over MgSO4, the solvent was evaporated to give crude product (13.1 g), which was further purified by vacuum distillation (80-83 C., 0.11 torr) to give the desired product (3.25 g, 20% yield) as a clear, colorless oil. 1H NMR (CDC13), d (ppm): 4.51 (t, 1 H, J=5.5); 4.05 (q, 2 H,J=7.1); 3.48 (m, 2H); 3.40-3.31 (m, 4H); 1.18 (t, 3 H,J=7.1); 1.11 (s, 6H). 13C NMR (CDCl3), d (ppm): 176.7, 72.0, 70.5, 60.3, 59.8, 41.3, 36.7, 24.88, 24.78, 14.0. HRMS calcd. for C11H23O4 (MH+): 219.1613, found 219.1605.

Quelle