反应详情

温度

2.5 °C

5-methyl-furan-3-one (2, 7.0 g g, 0.071 mol) was dissolved in dichloromethane (40 mL) and taken in a 3-necked 500 mL round bottomed flask fitted with a mechanical agitator and calcium chloride guard tube. Vanillin (3b, 9.0 g, 0.059 mol) dissolved in dichloromethane (40 mL) was added. The mixture was cooled to 0-5° C. with stirring. Tri-sec-butyl borate (15.0 g, 0.065 mol) was added and stirred for 2 h. The color of the reaction mixture turned yellow. n-Butyl amine (2 drops) was added and the reaction mixture allowed to warm to room temp. on its own and stirred at room temp. overnight. The yellow color of the reaction mixture intensified. This mixture was poured into 5% aq. acetic acid solution (120 mL) preheated to 60° C. with stirring. This was stirred for 30 min., and then allowed to settle down. The dichloromethane layer was isolated and concentrated under reduced pressure to get a red color thick liquid. Hexane (80 mL) was added to this gummy material and stirred overnight. A yellow color solid crystallized out. This was filtered, dried in vacuo at 110° C. to get pure 2-(4-hydroxy-3-methoxy-benzylidene)-5-methyl-furan-3-one (4b, 10.0 g, 61% yield) as pale yellow powder, m.p. 167.5°-170.0° C.

1. customtaken in a 3-necked 500 mL round bottomed flask
2. additionwas added
3. stirringstirred for 2 h
4. temperatureto warm to room temp. on its own
5. stirringstirred at room temp. overnight
6. custompreheated to 60° C.
7. stirringwith stirring
8. stirringThis was stirred for 30 min.
9. concentrationconcentrated under reduced pressure
10. customto get a red color thick liquid
11. stirringstirred overnight
12. customA yellow color solid crystallized out
13. filtrationThis was filtered
14. customdried in vacuo at 110° C.