反应详情

In a two liter flask fitted with a Dean Stark water separator and a condenser were placed 186.5 g. (0.85 mole) of benzyl oximino-acetoacetate [1.1], 62 g. (1 mole) of ethylene glycol, 800 ml. of benzene (reagent grade) and 2 g. (10.5 mmole) of p-toluenesulfonic acid monohydrate. The reaction mixture was boiled at reflux until 15 ml. of water was removed (3 hours). The benzene solution was washed once with saturated sodium bicarbonate solution and once with brine. After drying over anhyrous sodium sulfate, the benzene solution was evaporated, leaving 212 g. (94% yield) of benzyl oximino-acetoacetate ethylene ketal [2.1] as a light yellow oil ! Its NMR spectrum was consistent with the assigned structure. Generally, the product was used as such in subsequent reactions but one of the isomers can be crystallized2 from toluene-petroleum either (b.p. 30°-60° C.); m.p. 52° C.

1. temperatureat reflux until 15 ml
2. customof water was removed (3 hours)
3. washThe benzene solution was washed once with saturated sodium bicarbonate solution and once with brine
4. dry with materialAfter drying over anhyrous sodium sulfate
5. customthe benzene solution was evaporated
6. customleaving 212 g