反应详情

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. Tol.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 29 (0.931 g, 30%). 1H-n.m.r. (CDCl3): 5.83 (m, 1H, --CH=), 5.20 (m, 2H, =CH2), 3.95 (dd, 1H, J=5.5 and 1.0 Hz, allylics), 3.66 and 3.46 (two t, 2H each, J=6.5 Hz, O--CH2), 1.64 (m, 4H) and 1.44 (m, 2H): 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).

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