Sodium Carbonate → 4,7-Di(thiophen-2-yl)benzo(c)(1,2,5)thiadiazole

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Reaction Steps

A solution of 4,7-dibromobenzo[c][1,2,5]thiadiazole (3.0 g, 10.2 mmol) and thiophen-2-ylboronic acid (2.87 g, 22.4 mmol) in 150 mL of 1,2-dimethoxyethane and 50 mL anhydrous ethanol was carefully degassed by bubbling nitrogen through the solution. Next, 7.16 g (67.2 mmol) of sodium carbonate dissolved in 30 mL water was added. The resulting emulsion was degas sed, and the catalyst Pd(PPh3)4 (200 mg, 0.17 mmol) was added. Afterwards, the mixture was refluxed under nitrogen overnight. After removal of the organic solvent by reduced pressure, the mixture was poured into water (300 mL) and was extracted with chloroform (3×40 mL). The organic phase was washed with water (30 mL), dried over magnesium sulphate, and the solvent was removed in vacuo. Purification by flash silica gel column chromatography [hexane:chloroform=1:1 (v/v)] followed by recrystallization from hexane/dichloromethane (DCM) yielded orange crystals of TBT (2.6 g, 84.9%).

Provenance & Evidence