Toluene → 2-(3,5-ditert-butyl-4-hydroxy-benzoyl)-3-dimethylamino-N-methyl-prop-2-enamide

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Reaction Steps

A 100-mL round bottom flask was charged with 3-(3,5-ditert-butyl-4-hydroxy-phenyl)-N-methyl-3-oxo-propanamide (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.

Provenance & Evidence