Benzyl Alcohol → 1-Benzyloxy-3-chloro-2-propanol

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Reaction Steps

Epichlorohydrin is reacted with benzyl alcohol in the presence of tetrabutylammonium bisulfate in aqueous sodium hydroxide, at room temperature. The product of this reaction, benzyl glycidyl ether, is isolated by conventional means and is then added slowly to a suspension of lithium chloride in tetrahydrofuran and acetic acid, at 40°-70° C., preferably below 60° C. The reaction mixture is allowed to cool to room temperature, and stirred for 2-10 hours, preferably 3-6 hours. The product is isolated by extraction, washed and dried to provide 1-benzyloxy-3-chloro-2-propanol. To this product is then added methoxymethyl propionate, which is prepared by adding propionic anhydride to dimethoxymethane in the presence of an ion exchange resin, e.g., Amberlyst 15, maintaining the temperature between 40°-60° C., preferably between 40°-50° C. during the addition. The reaction mixture is aged and cooled, then filtered, washed and distilled. This product, methoxymethyl propionate, is reacted with 1-benzyloxy-3-chloro-2-propanol in an aprotic solvent, e.g., hexanes, in the presence of p-toluenesulfonic acid hydrate at reflux. Distillation and washing affords the product 1-benzyloxy-3-chloro-2-(propionyloxy)methoxypropane. Finally, to prepare the compounds of Formula (III), 1-benzyloxy-3-chloro-2-(propionyloxy)methoxypropane, is refluxed with an alkali metal alkanoate, e.g., sodium propionate, in an aprotic solvent, e.g., toluene, after which a phase transfer catalyst such as tetrabutylphosphonium chloride is added. The reaction mixture is stirred at 90° C. to reflux temperature for 1-3 days, preferably 2 days, at which time more tetrabutylphosphonium chloride and solvent may be added, if required. The mixture is heated to reflux and the distillate removed, then stirred at 90° C. to reflux temperature for 3-16 hours, preferably 5-10 hours, then cooled to ambient temperature. The mixture is then washed with water and brine, and the organic phase is separated and concentrated to yield 1-benzyloxy-3-propionyloxy-2-(propionyloxy)methoxy propane. In an analogous manner, other glycerol derivatives of Formula (III) may be prepared.

Provenance & Evidence