反应详情

A solution of 16.0 g. (0.14 mol) 4-methyl-3,4,5,6-tetrahydro-2-pyranone in 50 ml. anhydrous ethanol is saturated with hydrogen bromide gas at 0°-5° C., left to stand overnight, poured into water and extracted with diethyl ether. The combined ether extracts are dried over anhydrous sodium sulphate and evaporated and the residue is distilled in a vacuum to give 21.9 g. (70% of theory) of the desired product in the form of a colourless liquid; b.p. 85°-87° C./0.1 mm.; nD20 =1.4590.

1. waitleft
2. extractionextracted with diethyl ether
3. dry with materialThe combined ether extracts are dried over anhydrous sodium sulphate
4. customevaporated
5. distillationthe residue is distilled in a vacuum
6. customto give 21.9 g