Sodium Hydroxide → α-Oxo-1,3-dioxolane-2-pentanoic acid

Temperature

0 °C

A 3 L 3-necked round bottom flask was equipped with an overhead stirrer, thermocouple, and an addition funnel containing 1.5 N NaOH (460 mL). The flask was charged with MeOH (700 mL) and cooled to 0° C. The NaOH solution was added slowly to the methanol, maintaining the temperature below 10° C. and upon complete addition, the resulting solution was cooled to 0° C. A methanol solution of 5-(1,3-dioxolan-2-yl)-2-oxo-pentanoic acid, ethyl ester (350 mL) was added to the reaction via dropping funnel at a rate which maintained the temperature of the reaction mixture below 3° C. (addition time 1 hr). The reaction was stirred at 0° C. for 2 hours and the pH of the reaction was adjusted to 7.71 by the addition of 2 M potassium bisulfate (75 mL). The methanol was evaporated and the cloudy aqueous slurry was washed with MTBE (3×500 mL). The pH of the aqueous layer was adjusted to 4.5 by the addition of 2 M potassium bisulfate (100 mL) and extracted with ethyl acetate (500 mL). The pH of the aqueous layer was further adjusted to 2.0 by the addition of 2 M potassium bisulfate (50 mL), and extracted with ethyl acetate (2×500 mL). The combined ethyl acetate extracts were dried over magnesium sulfate and concentrated to afford 5-(1,3-dioxolan-2-yl)-2-oxo-pentanoic acid (60 g, 80 M % yield) as a thick liquid.

1. customA 3 L 3-necked round bottom flask was equipped with an overhead stirrer
2. temperaturemaintaining the temperature below 10° C.
3. additionupon complete addition
4. temperaturethe resulting solution was cooled to 0° C
5. temperaturemaintained
6. additionthe temperature of the reaction mixture below 3° C. (addition time 1 hr)
7. customThe methanol was evaporated
8. washthe cloudy aqueous slurry was washed with MTBE (3×500 mL)
9. additionThe pH of the aqueous layer was adjusted to 4.5 by the addition of 2 M potassium bisulfate (100 mL)
10. extractionextracted with ethyl acetate (500 mL)
11. additionThe pH of the aqueous layer was further adjusted to 2.0 by the addition of 2 M potassium bisulfate (50 mL)
12. extractionextracted with ethyl acetate (2×500 mL)
13. dry with materialThe combined ethyl acetate extracts were dried over magnesium sulfate
14. concentrationconcentrated

ORD record

ord-9c70471e8b694d809fdbd11fdd5741bb

Source dataset

uspto-grants-2000_10

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06140088