反应详情

17.5 g of 2,5-dimethyl-3,4-dihydroxy-tetrahydrofuran-3-one of about 80% purity were heated, in a suspension of 40 g of bismuth oxide and 50 g of glacial acetic acid, for 25 minutes at 120° C. After the reaction mixture had cooled, it was diluted with 80 g of ethyl acetate, whereupon metallic bismuth and bismuth acetate precipitated. The filtrate was fractionated, giving, at 85°-101° C./0.3 mbar, 14.2 g of a distillate containing about 77% of (I). This corresponds to a yield of 79%. 2.5 g of this fraction were taken up in a mixture of 2.8 g of chloroform and 1.6 g of petroleum ether, from which, after cooling, pure (I) of solidification point 75°-76° C. crystallized.

1. temperatureAfter the reaction mixture had cooled
2. customprecipitated
3. customgiving, at 85°-101° C./0.3 mbar, 14.2 g of a distillate
4. temperatureafter cooling
5. custompure (I) of solidification point 75°-76° C. crystallized