反应详情

温度

160 °C

8.9 g of p-cresol, 8.9 g of penta-O-acetyl-D-galactopyranose and 0.56 g of ZnCl2 are mixed, heated to 160° C. and kept at this temperature for 30 minutes, according to HELFERICH's method. After cooling to 60° C., the reaction medium is taken up with 400 ml of CH2Cl2 and washed with twice 400 ml of water and then with a solution of sodium hydroxide (≈1N) until the aqueous phase is practically colourless. The organic phase is finally washed with twice 400 ml of water, dried over anhydrous sodium sulfate and then evaporated to dryness in a water bath (temperature: 35°-40° C.) to give a residue of 7.08 g (yield=70%). Chromatography on a column of 60H silica (solvent: hexane/ethyl acetate: 90/10 v/v) gives 2.9 g of the compound 1 (yield=29%) and 1.17 g of its β anomer (yield=12%).

1. temperatureAfter cooling to 60° C.
2. washwashed with twice 400 ml of water
3. washThe organic phase is finally washed with twice 400 ml of water
4. dry with materialdried over anhydrous sodium sulfate
5. customevaporated to dryness in a water bath (temperature: 35°-40° C.)
6. customto give a residue of 7.08 g (yield=70%)