Malononitrile → Methyl 3,3-dicyano-2,2-dimethylpropanoate

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Reaction Steps

In THF (91 ml), 3 g (45.411 mmol) of malononitrile were added slowly to 1.816 g (45.411 mmol) of sodium hydride (60% in mineral oil). Subsequently, 5.876 ml (45.411 mmol) of methyl 2-bromo-2-methylpropanoate were added and the mixture was stirred at RT overnight. Thereafter, another 5.876 ml (45.411 mmol) of methyl 2-bromo-2-methylpropanoate were added and the mixture was heated at 50° C. overnight. Then yet another 1.762 ml (13.623 mmol) of methyl 2-bromo-2-methylpropanoate were added and the mixture was heated at 50° C. for a further 4 h. Saturated aqueous sodium bicarbonate solution was then added to the reaction, and the mixture was extracted three times with ethyl acetate. The combined organic phases were washed with saturated aqueous sodium chloride solution, dried over sodium sulfate, filtered and concentrated to dryness. This gave 8.9 g of crude product, which was purified by chromatography on silica gel (cyclohexane-ethyl acetate 4:1).

Provenance & Evidence