Acetic Acid → HCID 14302198, compound

Temperature

-20 °C

Under argon atmosphere, a solution of n-butyl lithium in hexane (1.64N, 26 ml, 0.043 mol) was dropwise added with stirring into a solution of anhydrous diisopropylamine (4.3 g, 0.043 mol) in anhydrous THF (35 ml) at -20° C. and the reaction mixture was stirred for 30 min. at -20° C. To the mixture was added dropwise a solution of ethyl 2-methyl-4-hexynoate (5.4 g, 0.035 mol) in anhydrous THF (15 ml) at -20° C. To the mixture was added anhydrous HMPA (2.25 ml, 0.013 mol). The reaction mixture was heated to room temperature and then stirred for 40 min. The mixture was again cooled to -30° C. and to the mixture was dropwise added a solution of methyl iodide (6.05 g, 0.043 mol) in anhydrous THF (5 ml). After warming to room temperature, the mixture was stirred for one hour, acetic acid (2.5 ml, 0.043 mol) was added, and the resulting mixture was concentrated. The residue was diluted with water (50 ml) and extracted with ethyl acetate (100 ml×2). The combined ethyl acetate layer were washed with water (30 ml) and with brine (20 ml), dried over anhydrous sodium sulfate, and concentrated. Distillation of the residue in vacuo give ethyl 2,2-dimethyl-4-hexynoate (3.7 g, 0.022 mol, 62%, B.p.: 65°-68° C./10 mmHg). The product was assigned the structure by the following data.

1. temperatureThe reaction mixture was heated to room temperature
2. stirringstirred for 40 min
3. temperatureThe mixture was again cooled to -30° C. and to the mixture
4. temperatureAfter warming to room temperature
5. stirringthe mixture was stirred for one hour
6. concentrationthe resulting mixture was concentrated
7. additionThe residue was diluted with water (50 ml)
8. extractionextracted with ethyl acetate (100 ml×2)
9. washThe combined ethyl acetate layer were washed with water (30 ml) and with brine (20 ml)
10. dry with materialdried over anhydrous sodium sulfate
11. concentrationconcentrated
12. distillationDistillation of the residue in vacuo

ORD record

ord-757b405260e04d55a9f040ada38cc9bb

Source dataset

uspto-grants-1988_10

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US04775692