3,4-Dichloro-1,2,5-thiadiazole → 1,2,5-Thiadiazole, 3-chloro-4-(2-thienyl)-

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Reaction Steps

0.92 g (0.00246 mol) of 2-(tributylstannyl)thiophene and 0.12 g (0.0001 mol) of tetrakis(triphenylphosphine)palladium(0) were added to a solution of 0.33 g (0.00213 mol) of 3,4-dichloro-1,2,5-thiadiazole in 4 mL of toluene under nitrogen and heated at reflux. After 3 and 6 h respectively, 0.04 g (2 times 2.5×10−5 mol) of tetrakis (triphenylphosphine)palladium(0) were added. After 24 h of reflux (quantitative HPLC: 54% of product formed, all the stannane was consumed), the reaction medium was diluted with 5 mL of ethyl acetate and vigorously stirred with 10 mL of a 1M aqueous solution of KF for 2 h. After filtration through celite, the aqueous phase was re-extracted with ethyl acetate, the combined organic phases were dried over magnesium sulfate and concentrated.

Provenance & Evidence