Hydrochloric Acid → HCID 15327237, compound

Temperature

0 °C

28 (ethyl (2E)-2-methyl-4-oxopent-2-enoate) (HPLC: ˜84 area %, 16.73 g, 90 mmol) is dissolved in MeOH (500 ml) and cooled to 0° C. To the resulting solution is added NaBH4 (1.04 g, 27.5 mmol) in portions over 30 min. After 3 hours additional stirring at 0° C., the pH is adjusted to 5 with 2 M HCl (12 ml). The reaction mixture is concentrated under reduced pressure at room temperature. H2O (100 ml) is added. After acidification with 2 M HCl to pH 1, extraction with tBuOMe (1 and 0.5 l) follows. The organic phases are washed with H2O (100 ml) and brine (2×100 ml) successively. The combined organic phases are dried with Na2SO4 and evaporated under reduced pressure at 40° C. The residue is purified by flash chromatography (AcOiPr:heptane fraction 20:80 to 40:60) and yields 29 (rac-Ethyl (2E)-4-hydroxy-2-methylpent-2-enoate) (11.26 g, 79%) as a yellowish oil.

1. concentrationThe reaction mixture is concentrated under reduced pressure at room temperature
2. additionH2O (100 ml) is added
3. extractionAfter acidification with 2 M HCl to pH 1, extraction with tBuOMe (1 and 0.5 l)
4. washThe organic phases are washed with H2O (100 ml) and brine (2×100 ml) successively
5. dry with materialThe combined organic phases are dried with Na2SO4
6. customevaporated under reduced pressure at 40° C
7. customThe residue is purified by flash chromatography (AcOiPr:heptane fraction 20:80 to 40:60)

ORD record

ord-33dab8293bc74790b2bba284387f3812

Source dataset

uspto-grants-2012_10

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08288566B2