1,4-Butanediol → 1,3-Dioxepane, 2-(chloromethyl)-

Beteiligte Stoffe

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500 gms of chloroacetaldehyde dimethyl acetal (Aldrich catalog no C1940-6), 360 gms of 1,4-butanediol (Aldrich catalog no. 88,480 7) and 10 gms of Dowex 50 resin (Aldrich catalog No. 21,749-2) were placed in a 1000 ml, 3-neck round bottom flask equipped with a thermometer, a mechanical stirrer, a 8 inch Pen State column, and a distillation head. The mixture was heated to 115° C. under nitrogen blanket and methanol was removed continuously and the amount collected was measured by weigh up. The reaction was monitored by analyzing samples taken from the distillate in a Gas Chromatograph with a dimethyl silicon column in the temperature range of 50° C. to 250° C. The reaction was stopped when the stoichiometric amount of methanol was collected. The crude reaction mixture was filtered to remove the ion exchange resin. The product 2-chloromethyl 1,3-dioxepane was isolated from the crude mixture by fractional distillation in an Oldershaw column under partial vacuum. The fraction boiling at 105° C. at 55 mm of Hg was collected. The structure was confirmed by elemental analysis and proton NMR. Elemental analysis: C-47.2 percent (48 percent calculated), H=7.58 percent (7.33 percent calculated), 0=22.64 percent (21.34 percent calculated), C1=22.57 percent (23.3 percent calculated). Proton NMR:1.71-1.34 ppm multiplet (--OCH2CH2CH2CH2O--), 3.46-3.48 ppm doublet (--CH2Cl), 3.66-2.96 ppm 2 sets of triplets (--OCH2 ; 2 sets, 4 protons), 4.83-4.87 ppm triplet (C1CH2CH(O)2).

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