Propyne → 2-hexylthio-7-(1-propynyl)-5H-1,3,4-thiadiazolo[3,2-a]pyrimidin-5-one

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Reaction Steps

Into a solution of 8.6 g of the thus obtained 7-iodo-2-hexylthio-5H-1,3,4-thiadiazolo[3,2-a]pyrimidin-5-one, 11 g of triethylamine, 0.15 g of bis(triphenylphosphine)palladium(II) chloride, 0.04 g of cuprous iodide and 33 ml of tetrahydrofurane, 2.6 g of 1-propyne was introduced through a bubbling glass tube under ice-cold-water chilling and constant stirring over a 1 hour period. Thereafter, the solution was further stirred at room temperature for 30 minutes, and 0.23 g of bis(triphenylphosphine)palladium(II) chloride and 0.06 g of cuprous iodide were added. The solution was stirred further for 4 hours. Then toluene was added, and the solution was filtered, and the filtrate was concentrated under reduced pressure. The residue was dissolved in toluene, the solution was washed with water and dried over anhydrous sodium sulfate. The solvent was distilled off and the residue was recrystallized from an ethanol/hexane mixture and thus 3.9 g of 7-(1-propynyl)-2-hexylthio-5H-1,3,4-thiadiazolo[3,2-a]pyrimidin-5-one was obtained. m.p. 94°~97° C. Yield 72%.

Provenance & Evidence