Reacción #1539635

Ecuación de reacción

3,5-dibromobenzonitrile

thiophene-3-boronic acid

tri-o-tolylphosphine

sodium carbonate

→

3-bromo-5-(thien-3-yl)benzonitrile

Disolventes

acetonitrile

Condiciones de reacción

Tratamiento posterior

1. 1
   Temperaturawas refluxed under nitrogen for 6 hours
2. 2
   Concentraciónconcentrated under reduced pressure
3. 3
   Extracciónextracted with diethyl ether (3×80 mL)
4. 4
   LavadoThe combined organic extracts were washed with water (150 mL), saturated aqueous sodium bicarbonate (150 mL), and brine (50 mL)
5. 5
   Secadodried over magnesium sulfate
6. 6
   Otrochromatographed on silica
7. 7
   Lavadoeluted with a mobile phase of ethyl acetate in hexane
8. 8
   ConcentraciónThe first fraction was concentrated under reduced pressure

Procedimiento

A mixture of 3,5-dibromobenzonitrile (3 g, 11.5 mmol), thiophene-3-boronic acid (2.35 g, 18 mmol), dichlorobis(triphenylphosphine)palladium(II)(1.21 g, 1.7 mmol), tri-o-tolylphosphine (0.524 g, 1.7 mmol), sodium carbonate (3.46 g, 33 mmol) in aqueous acetonitrile (1:10), 110 mL) was refluxed under nitrogen for 6 hours, cooled to room temperature, concentrated under reduced pressure, suspended in hydrochloric acid (2N, 50 mL), and extracted with diethyl ether (3×80 mL). The combined organic extracts were washed with water (150 mL), saturated aqueous sodium bicarbonate (150 mL), and brine (50 mL), dried over magnesium sulfate, adsorbed onto silica, chromatographed on silica and eluted with a mobile phase of ethyl acetate in hexane. The first fraction was concentrated under reduced pressure to leave 3-bromo-5-(thien-3-yl)benzonitrile in the form of a yellow amorphous solid. Yield 1.47 g (48 percent). mp 62-63° C.; 1H NMR (CDCl3) δ 7.94 (t, J=1.8 Hz, 1H), 7.79 (t, J=1.5 Hz, 1H), 7.69 (t, J=1.8 Hz, 1H), 7.54 (dd, J1=3.0 Hz, J2=1.5 Hz, 1H), 7.46 (dd, J1=5.1 Hz, J2=3.0 Hz, 1H), 7.34(dd, J1=4.8 Hz, J2=1.5 Hz, 1H); EI/MS 265 m/e (M+); IR (KBr) σ cm−1 2230.

Fuente