Reaktion #1766177
ord-9d0b811e284443458ed1aaed2de630ae
Reaktionsgleichung
Reagenzien
Lösungsmittel
Reaktionsbedingungen
Aufarbeitung
- 1SonstigeThe latter was prepared
Vorschrift
In another method of preparing the 5-benzyloxy-1,3-dioxane, the starting material was 5-hydroxy-1,3-dioxane (Tetrahedron 7, 10-18 (1959)). The latter was prepared by first reacting glycerol with trioxymethylene, in the presence of HCl as a catalyst to form a mixture of cyclic acetals (J. Am. Chem. Soc. 50, 3124 (1928)) which was then esterified with benzoyl chloride, in the presence of pyridine, yielding on recrystallization the benzoate 5-hydroxy-1,3-dioxane melting at 71°-72° C (J. Am. Chem. Soc. 50, 3120 (1928)). This ester was then split by reaction with sodium methylate in chloroform, to produce the purified 5-hydroxy-1,3-dioxane which was taken off as a cut boiling at 95°-96° C at 22 mm. Three grams (0.029 mol) of the latter product and 100 ml of benzene were placed in a flask equipped with a stirrer, condenser, thermometer and addition funnel. While stirring, 1.1 g of sodium hydride was added portionwise; hydrogen evolved. Next, after the resulting slurry had been kept at room temperature for 1/2 hour without further addition of ingredients while stirring continued, 3.65 g of benzyl chloride was added dropwise over a fifteen minute period. When all the benzyl chloride had been added the mixture was heated to 80° C and maintained at this temperature for 24 hours while stirring continued. The slurry thus obtained was then washed twice with 100 ml portions of water and the resulting organic layer was dried over MgSO4. This drying agent was then filtered off and the solvent was removed under reduced pressure, yielding an oil which was then distilled under reduced pressure to give a fraction (5-benzyloxy-1,3-dioxane) boiling at 80°-82° C at 0.15 mm and having an estimated purity of about 85%.