Reaktion #1951056

Reaktionsgleichung

4-fluorobenzyl bromide

trimethyl phosphite

→

(4-fluoro-benzyl)-phosphonic acid dimethyl ester

Ausbeute 67.5%

Lösungsmittel

ethyl acetate

Reaktionsbedingungen

Aufarbeitung

1. 1
   Sonstigeat 90° C.
2. 2
   Sonstigeovernight
3. 3
   Temperaturto cool to ambient temperature
4. 4
   WaschenThe solution was washed with saturated sodium bicarbonate (350 mL)
5. 5
   TrocknenThe organic phase was dried with magnesium sulfate
6. 6
   Filtrationfiltered
7. 7
   Einengenconcentrated by rotatry evaporation
8. 8
   SonstigeThe resulting crude product was purified by flash silica chromatrography

Vorschrift

4-fluorobenzyl bromide (25 mL, 0.20 mol) was added to a stirred solution of trimethyl phosphite (35.9 mL, 0.30 mol) at ambient temperature, under a nitrogen atmosphere. The resulting solution was heated at 110° C. for six hours, and then at 90° C. overnight. The reaction mixture was allowed to cool to ambient temperature and then ethyl acetate (350 mL) was added. The solution was washed with saturated sodium bicarbonate (350 mL) and then with saturated brine (2×350 mL). The organic phase was dried with magnesium sulfate, filtered, and concentrated by rotatry evaporation. The resulting crude product was purified by flash silica chromatrography using 0-35% acetonitrile in ethyl acetate as eluant to yield (4-fluoro-benzyl)-phosphonic acid dimethyl ester (29.44 g, 135 mmol, 66% yield) as a colorless oil. 1H NMR (400 MHz, DMSO) δ 7.33-7.28 (m, 2H); 7.17-7.12 (dd, 2H); 3.61-3.58 (d, 6H); 3.31-3.24 (d, 2H); ESMS (m/z): (M+1)+ found, 219.

Quelle