Isopropyl chloroformate → HCID 86669327, compound

To a solution of acid from Step 1 (2.92 g, 13.9 mmol) in a mixture of THF/DMF (5:1, 60 mL) was added isopropylchloroformate (2.71 mL, 20.9 mmol). After 20 h of stirring at room temperature, the solution was cooled to 0° C. and NaBH4 (1.06 g, 27.9 mmol) followed methanol (5 mL) was added to the solution. After 30 min of stirring, a saturated aqueous solution of ammonium chloride was added (20 mL) and followed by ethyl acetate (20 mL). The layers were separated and the aqueous layer was extracted with ethyl acetate (2×30 mL). The combined organic layers were washed with brine, dried with magnesium sulfate, filtered and the filtrate was concentrated in vacuo. The residue was purified by silica gel chromatography (hexanes/ethyl acetate 95:5 to 60:40). After evaporation at low temperature, ethyl 5-hydroxy-4,4-dimethyl-pentanoate (1.82 g, 75% yield) was obtained as a volatile colorless oil.

1. temperaturethe solution was cooled to 0° C.
2. additionwas added to the solution
3. stirringAfter 30 min of stirring
4. customThe layers were separated
5. extractionthe aqueous layer was extracted with ethyl acetate (2×30 mL)
6. washThe combined organic layers were washed with brine
7. dry with materialdried with magnesium sulfate
8. filtrationfiltered
9. concentrationthe filtrate was concentrated in vacuo
10. customThe residue was purified by silica gel chromatography (hexanes/ethyl acetate 95:5 to 60:40)
11. customAfter evaporation at low temperature

ORD record

ord-b2f2b5ffbac14334985ca7373ef8f89b

Source dataset

uspto-grants-2015_06

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US09051248B2