Ethyl 4-bromobenzoate → Ethyl 4-(diethoxyphosphoryl)benzoate

A sealed pressure flask, flushed with N2, containing a mixture of 4-bromo-benzoic acid ethyl ester (2a) (5 g, 0.0218 mol), diethyl phosphite (3.093 mL, 0.024 mol), NMM (2.88 mL, 0.0262 mmol) and Pd(PPh3)4 (2.017 g, 0.00175 mol) in acetonitrile (20 mL) was stirred at ambient temperature for 5-10 min, then heated at 90° C. for 18 hours. The reaction mixture was filtered through celite, and the celite was washed with EtOAc (3×30 mL) until the filtrate showed little or no evidence of product by HPLC. The combined organics were dried over Na2SO4 and concentrated on a rotary evaporator. The desired product was purified by silica gel flash chromatography to give a pale yellow oil (4.24 g). 1H NMR (300 MHz, CDCl3) δ (ppm)) 1.36 (m, 6H), 1.42 (t, J=7 Hz, 3H), 4.16 (m, 4H), 4.42 (q, J=7 Hz, 2H),7.93 (m, 2H), 8.15 (m, 2H). 31P NMR (121 MHz, CDCl3) δ 17.63.

1. customA sealed pressure flask, flushed with N2
2. additioncontaining
3. temperatureheated at 90° C. for 18 hours
4. filtrationThe reaction mixture was filtered through celite
5. washthe celite was washed with EtOAc (3×30 mL) until the filtrate
6. dry with materialThe combined organics were dried over Na2SO4
7. concentrationconcentrated on a rotary evaporator
8. customThe desired product was purified by silica gel flash chromatography

ORD-Eintrag

ord-4972b91a55274c0484a1ab33aa00a9e3

Quelldatensatz

uspto-grants-2005_11

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US06960572B2