反应详情

A mixture of 3.6 g of 2-(4-pentenyl)-1,3-propanediol, 4,4 of p-(3-butenyl)oxybenzaldehyde, 75 ml of toluene and 3 drops of 10 percent sulphuric acid is heated to boiling for 2.5 hours, whereby about 50 ml of wet solvent are distilled off and are replaced by the dropwise addition of 50 ml of fresh toluene. Thereafter, the mixture is neutralized with 4 drops of triethylamine and, after cooling, is washed with 5 percent sodium hydrogen carbonate solution and water. The organic phase is dried over sodium sulphate and concentrated. Chromatographic separation of the residue on silica gel with hexane/ethyl acetate and recrystallization from hexane gives trans-2-[p-(3-butenyl)oxyphenyl]-5-(4-pentenyl)-m-dioxane with m.p. (C-I) 17.8° C. and cl.p. (N-I) 7.3° C.

1. temperatureis heated
2. distillationwhereby about 50 ml of wet solvent are distilled off
3. additionare replaced by the dropwise addition of 50 ml of fresh toluene
4. temperatureafter cooling
5. washis washed with 5 percent sodium hydrogen carbonate solution and water
6. dry with materialThe organic phase is dried over sodium sulphate
7. concentrationconcentrated
8. customChromatographic separation of the residue on silica gel
9. customwith hexane/ethyl acetate and recrystallization from hexane