Sodium Carbonate → Ethyl 2-[2-(4'-nitro-1,1'-biphenyl-4-yl)-2-oxoethyl]pentanoate

Temperatur

85 °C

To a 150 mL 3-neck flask fitted with a reflux condenser was added ethyl 2-[2-(4-bromophenyl)-2-oxoethyl]pentanoate (1.33 g, 4.10 mmol) and 4-nitro phenyl boronic acid (0.81 g, 4.9 mmol), dissolved in toluene (37 mL) and dioxane (10 mL), followed by addition of saturated aqueous sodium carbonate (11 mL). A thin-gauge needle was inserted into the bi-phasic mixture and the mixture was degassed with argon over 30 minutes, at which point 1,2-bis[(diphenylphosphino) ferrocene] dichloropalladium(II) (0.17 g, 0.20 mmol) was added, followed by 15 minutes of degassing. The mixture was heated to 85° C. for 16 h. The very darkly colored reaction mixture was allowed to cool, and diluted with ethyl acetate (100 mL) and saturated aqueous sodium chloride solution (100 mL). The layers were separated, the aqueous layer extracted twice with ethyl acetate (50 mL), and the combined organic layers were washed with saturated aqueous sodium chloride solution (75 mL), dried over anhydrous magnesium sulfate, and filtered in vacuo through 2 cm Celite®/2 cm silica. The filtrate was concentrated under reduced pressure, leaving a dark red-brown oil, that was purified by flash chromatography (10:1 hexane:ethyl acetate, then 7:1 hexane:ethyl acetate, then 4:1 hexane:ethyl acetate) to afford ethyl 2-[2-(4′-nitro-1,1′-biphenyl-4-yl)-2-oxoethyl]pentanoate (0.71 g, 48%). LC-MS ret. time 3.88 min, m/z 369.8 (MH+); 1H NMR (300 MHz, CDCl3) δ 0.95 (t, 3H), 1.30 (t, 3H), 1.35–1.50 (m, 2H), 1.60–1.83 (m, 2H), 3.0–3.18 (m, 2H), 3.5 (dd, 1H), 4.20 (q, 2H), 7.65–7.88 (overlapping d, 4H), 8.10 (d, 2H), 8.35 (d, 2H).

1. customTo a 150 mL 3-neck flask fitted with a reflux condenser
2. additionwas added
3. customof degassing
4. temperatureto cool
5. additiondiluted with ethyl acetate (100 mL) and saturated aqueous sodium chloride solution (100 mL)
6. customThe layers were separated
7. extractionthe aqueous layer extracted twice with ethyl acetate (50 mL)
8. washthe combined organic layers were washed with saturated aqueous sodium chloride solution (75 mL)
9. dry with materialdried over anhydrous magnesium sulfate
10. filtrationfiltered in vacuo through 2 cm Celite®/2 cm silica
11. concentrationThe filtrate was concentrated under reduced pressure
12. customleaving a dark red-brown oil, that
13. customwas purified by flash chromatography (10:1 hexane

ORD-Eintrag

ord-a78d2dcb1e5548479df3ef45416b6e74

Quelldatensatz

uspto-grants-2006_08

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US07091228B2