反应详情

A mixture of 1.00 g of 2-(trans-1-pentenyl)-1,3-propanediol, 1.11 g of p-butoxybenzaldehyde, 3 drops of 2N sulphuric acid and 40 ml of toluene was heated to reflux for 2 hours with separation of water. The mixture was subsequently treated with 7 drops of triethylamine, left to cool, washed with 5 ml of saturated sodium hydrogen carbonate solution and three times with 10 ml of water each time, dried over sodium carbonate, filtered and concentrated. The semi-crystalline residue (1.86 g) was chromatographed on silica gel with hexane/diethyl ether (vol. 97:3). The product-containing fractions were pooled (0.99 g) and recrystallized twice from hexane at -25° C. There was obtained 0.44 g of pure trans-2-(p-butoxyphenyl)-5-(trans-1-pentenyl)-m-dioxane; m.p. (C--N) 60.6° C., cl.p. (N--I) 61.9° C.

1. temperaturewas heated
2. waitleft
3. temperatureto cool
4. washwashed with 5 ml of saturated sodium hydrogen carbonate solution and three times with 10 ml of water each time
5. dry with materialdried over sodium carbonate
6. filtrationfiltered
7. concentrationconcentrated
8. customThe semi-crystalline residue (1.86 g) was chromatographed on silica gel with hexane/diethyl ether (vol. 97:3)
9. customrecrystallized twice from hexane at -25° C