Ammonium Chloride → HCID 118175696, Verbindung

Temperatur

-10 °C

A solution of (S)-2-hydroxy-3-methyl-butyric acid methyl ester (1.32 g, 10 mmol) in tetrahydrofuran (30 mL) was stirred at −10° C. under nitrogen. Sodium bis(trimethylsilyl)amide (6 mL, 12 mmol, 2 M in tetrahydrofuran) was added dropwise and the reaction mixture was stirred at −10° C. for 10 min. Trifluoro-methanesulfonic acid 2-methyl-but-3-enyl ester (2.18 g, 10 mmol) was added in one portion and the reaction mixture was stirred at room temperature for 2 h. Saturated ammonium chloride solution was added and the mixture was extracted with ethyl acetate. The organic extracts were combined, washed with water and brine, dried over anhydrous magnesium sulfate, filtered and evaporated. The residue was purified by silica gel chromatography using a gradient of iso-hexanes/diethyl ether 20:1 to 10:1 to afford the title compound (429 mg, 21% over 2 steps) as an oil, as a 1:1 mixture of two diastereoisomers. 1H NMR (300 MHz, CDCl3) δ 0.96-0.99 (m, 6H), 1.05 (d, J=6.9 Hz, 1.5H), 1.08 (d, J=6.6 Hz, 1.5H), 2.01-2.12 (m, 1H), 2.45-2.56 (m, 1H), 3.06-3.21 (m, 1H), 3.44-3.60 (m, 2H), 3.76 (s, 3H), 5.00-5.11 (m, 2H), 5.74-5.88 (m, 1H).

1. stirringthe reaction mixture was stirred at room temperature for 2 h
2. extractionthe mixture was extracted with ethyl acetate
3. washwashed with water and brine
4. dry with materialdried over anhydrous magnesium sulfate
5. filtrationfiltered
6. customevaporated
7. customThe residue was purified by silica gel chromatography

ORD-Eintrag

ord-0829b71f5cf745ee99efcaee12ad8e10

Quelldatensatz

uspto-grants-2015_06

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US09062092B2