反应详情

A 100-mL round bottom flask was charged with 3-(3,5-di-tert-butyl-4-hydroxy-phenyl)-3-oxo-propanoic acid methyl amide (3.05 mg, 10 mmol) and toluene (20 mL). The mixture was heated and to the resulting hot solution was added N,N-dimethylformamide dimethyl acetal (1.50 mL, 11.3 mmol) with evolution of methanol. The mixture was stirred for 5 h without further heating then evaporated to an oil that was taken up in ethyl acetate (50 mL). The resulting solution was washed with water (4×50 mL) then with brine (20 mL), dried with sodium sulfate and evaporated to an oil and then further dried to a solid foam that was kept under high vacuum to reach a constant weight, then ground to a fine powder to afford 3.55 g of the title compound (98%). TLC (ethyl acetate) Rf 0.09. This material, and especially the equivalent material derived from N,N-dimethylacetamidine dimethyl acetal, is readily hydrolyzed to the starting material. It is therefore advisable to use the condensation product directly and immediately after solvent removal.

1. temperatureThe mixture was heated and to the resulting hot solution
2. temperaturewithout further heating
3. customthen evaporated to an oil that
4. washThe resulting solution was washed with water (4×50 mL)
5. dry with materialwith brine (20 mL), dried with sodium sulfate
6. customevaporated to an oil
7. customfurther dried to a solid foam that