Methyl acetoacetate → Methyl 3-oxooctadecanoate

Participants

Reaction Steps

Four liters of a suspension of 440 g (11 mol) of 60% sodium hydride in dried tetrahydrofuran was cooled to 0° C. Thereto was added dropwise 1.8 L of a tetrahydrofuran solution of 1.161 kg (10 mol) of methyl acetoacetate. After this mixture was stirred at room temperature for 1 hour, 3.023 kg (11 mol) of hexadecanoyl chloride was added dropwise at 0 to 5° C. and the resultant mixture was stirred at room temperature overnight. Thereafter, the tetrahydrofuran was distilled off, and the residue was poured into ice water and extracted with 8 L of ethyl acetate. The ethyl acetate was distilled off, and the residue was poured into a mixture of 400 g of a 28% methanol solution of sodium methoxide and 1.2 L of methanol. The resultant mixture was stirred with heating at 60 to 65° C. for 6 hours. The reaction mixture was cooled with ice, and the pH thereof was then adjusted to 5 with 10% sulfuric acid. This reaction mixture was extracted with ethyl acetate. The ethyl acetate layer was washed with 5% aqueous sodium carbonate solution and saturated aqueous common salt solution. Thereafter, the ethyl acetate was distilled off and the concentrate was recrystallized from methanol to obtain 1.72 kg (5.5 mol) of methyl 3-oxooctadecanoate. Yield, 55%.

Provenance & Evidence