反应详情

温度

-5 °C

2-Acetoxyacetyl chloride (6.42 g, 4.7 mmol) is added slowly to a mixture of 1A (7.62 g, 4.2 mmol) and toluene (50 ml), which is cooled to −5° C. After the addition is complete, the mixture is stirred for a further 1 hour at −5° C., then allowed to warm to room temperature and stirred for a further 1.5 hours. The reaction mixture is then cooled down to −3° C. and a mixture of triethylamine (6.5 ml, 4.7 mmol) and toluene (25 ml) is added slowly to the mixture. The mixture is stirred for a further 16 hours, during which time the temperature is gradually allowed to rise to room temperature. The mixture is filtered, and the filtrate is washed three times with water, dried over sodium sulfate and evaporated in vacuo to give the crude product (12.0 g, 89%) as an oil. A portion of this crude material (4 g) is purified by flash column chromatography, eluting with a mixture of ethyl acetate and petroleum ether (1:4) to give pure product (2.3 g, equivalent to 51% overall), with m.p. 38-40° C. NMR analysis of this indicates that the product has a purity of about 88 mol %, the impurity consisting mainly of two isomeric products.

1. additionAfter the addition
2. temperatureto warm to room temperature
3. stirringstirred for a further 1.5 hours
4. temperatureThe reaction mixture is then cooled down to −3° C.
5. additionis added slowly to the mixture
6. stirringThe mixture is stirred for a further 16 hours, during which time the temperature
7. customto rise to room temperature
8. filtrationThe mixture is filtered
9. washthe filtrate is washed three times with water
10. dry with materialdried over sodium sulfate
11. customevaporated in vacuo