Sodium sulphate hydrate → (4R)-4-methylnonanoic acid

Temperature

0 °C

(R)-2,6-Dimethylundec-2-ene 153 (10.03 g, 55.03 mmol) was dissolved in acetone (270 mL) and cooled to 0° C. Jones reagent (CrO3/H2SO4) (2.7 M, 120 mL) was added dropwise, and the reaction allowed to warm to room temperature over 18 hours. The reaction was poured on to water/Na2SO4 (200 mL), and the aqueous layer extracted with ethyl acetate (4×100 mL). The combined organics were dried over MgSO4, filtered, and rotovapped to give an oil. The crude oil was dissolved in CH2Cl2 (400 mL) and cooled to −78° C. Ozone was bubbled into reaction until blue to remove traces of the impurity (6E)(3S)-3,7-dimethylocta-1,6-diene. Dimethylsulfide (5 mL) was added, and the reaction stirred at room temperature for 2 hours. The solvent was removed, and the crude material chromatographed on silica eluting with 20% EtOAc/hex to give oil. The oil was dissolved in ether (100 mL) and extracted with 10% NaOH (2×25 mL). The aqueous layers were combined and extracted with ether (50 mL). The aqueous layer was cooled to 0° C. and acidified with HCl. The acidic layer was extracted with EtOAc (3×100 mL), and the combined extracts dried over MgSO4, filtered and rotovapped to give 154 as an oil (6.86 g, 54%). 1H NMR (400 MHz, CDCl3) δ 2.40–2.25 (m, 4H), 1.70–1.62 (m, 2H), 1.47–1.11 (m, 8H), 0.87–0.84 (m, 6H); [α]D=−11.4 (c1 in CHCl3).

1. temperatureto warm to room temperature over 18 hours
2. extractionthe aqueous layer extracted with ethyl acetate (4×100 mL)
3. dry with materialThe combined organics were dried over MgSO4
4. filtrationfiltered
5. customto give an oil
6. temperaturecooled to −78° C
7. customOzone was bubbled into reaction until blue
8. customto remove traces of the impurity (6E)(3S)-3,7-dimethylocta-1,6-diene
9. additionDimethylsulfide (5 mL) was added
10. customThe solvent was removed
11. customthe crude material chromatographed on silica eluting with 20% EtOAc/hex
12. customto give oil
13. extractionextracted with 10% NaOH (2×25 mL)
14. extractionextracted with ether (50 mL)
15. temperatureThe aqueous layer was cooled to 0° C.
16. extractionThe acidic layer was extracted with EtOAc (3×100 mL)
17. dry with materialthe combined extracts dried over MgSO4
18. filtrationfiltered

ORD record

ord-1238684ceba547cb8f3448f375561a4b

Source dataset

uspto-grants-2006_11

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07138542B2