Acetic Acid → Dimethyl (3-methyl-2-oxobutyl)phosphonate

Temperatur

-78 °C

Dimethyl methylphosphonate (8.8 g, 0.071 mol) was dissolved in anhydrous THF (100 ml) under argon atmosphere. To the solution stirred at -78° C. was added dropwise n-butyl lithium (1.58N, 45 ml, 0.071 mol) over 30 minutes and then a solution of methyl isobutyrate (2.9 g, 0.0284 mol) in anhydrous THF (5 ml) was added dropwise over 30 minutes. The reaction mixture was warmed to room temperature. After 30 minutes, acetic acid (4.3 ml) and water (10 ml) were added with ice cooling. After concentration, water (20 ml) was added to the residue and the mixture was extracted with ethyl acetate (50 ml×2). The ethyl acetate layers were washed with water (20 ml×1) and with brine (20 ml×1), dried over anhydrous sodium sulfate, and concentrated. Distillation of the residue gave dimethyl 3-methyl-2-oxo-butylphosphonate (4.8 g, 0.025 mol, yield 88%, b.p.= 82°-84° C./0.31 mmHg). The structure was identified by the following data.

1. temperatureThe reaction mixture was warmed to room temperature
2. concentrationAfter concentration, water (20 ml)
3. additionwas added to the residue
4. extractionthe mixture was extracted with ethyl acetate (50 ml×2)
5. washThe ethyl acetate layers were washed with water (20 ml×1) and with brine (20 ml×1)
6. dry with materialdried over anhydrous sodium sulfate
7. concentrationconcentrated
8. distillationDistillation of the residue

ORD-Eintrag

ord-7b5c12fddb154797b17ba72cd4a46851

Quelldatensatz

uspto-grants-1988_10

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US04775692