Reaktion #351103

Reaktionsgleichung

Allyl bromide

1,5-pentanediol

sodium hydride

pentanediol

→

compound 229

Ausbeute 30.0%

Allyloxy-5-pentanol

Ausbeute 30.0%

Lösungsmittel

ethyl acetate

dimethylformamide

Reaktionsbedingungen

Aufarbeitung

1. 1
   SonstigeThe unreacted sodium hydride was destroyed by addition of methanol
2. 2
   EinengenThe mixture was concentrated to 50 mL by evaporation in vacuo
3. 3
   WaschenAfter dilution with methylene chloride (150 mL), the solvents were washed with water (three times)
4. 4
   Trocknendried over magnesium sulfate
5. 5
   Sonstigeevaporated in vacuo
6. 6
   SonstigeThe residue was chromatographed on silica gel using
7. 7
   workup.ADDITIONa 2:1 mixture of toluene and ethyl acetate as eluant

Vorschrift

Allyl bromide (2.5 mL, 0.029 mol) was added dropwise to the mixture of 1,5-pentanediol (3 g, 0.029 mol) and sodium hydride (1.2 g, 80% dispersion in oil) in dry dimethylformamide. Stirring was continued overnight at room temperature. T.l.c. (2:1-toluene and ethyl acetate) still indicated the presence of some unreacted pentanediol. The unreacted sodium hydride was destroyed by addition of methanol. The mixture was concentrated to 50 mL by evaporation in vacuo. After dilution with methylene chloride (150 mL), the solvents were washed with water (three times), dried over magnesium sulfate and evaporated in vacuo. The residue was chromatographed on silica gel using a 2:1 mixture of toluene and ethyl acetate as eluant. The appropriate fractions gave compound 229 (0.931 g, 30%). 1H-n.m.r. (CDCl3): 5.83 (m, 1 H, --CH=), 5.20 (m, 2 H, =CH2), 3.95 (dd, 1 H, J=5.5 and 1.0 Hz, allylics), 3.66 and 3.46 (two t, 2 H each, J=6.5 Hz, O--CH2), 1.64 (m, 4 H) and 1.44 (m, 2 H): methylenes); 13C-n.m.r. (CDCl3): 134.7 and 116.6 (ethylenics), 71.6, 70.1 (CH2 --O--CH2), 62.1 (CH2OH) 32.2, 29.2 and 22.2 (methylenes).

Quelle