Acetic Acid → Zinc copper couple

Participants

Reaction Steps

A zinc-copper couple was prepared following the procedure of Bradley (J. Org. Chem. 31, 626 (1966)) by stirring 1.0 g of copper sulfate in 20 ml of water with 15.0 g of zinc dust for 2 hours. The couple was collected by filtration, washed with acetone and dried overnight under vacuum at 100° C. To a solution of 33.0 g (106 mmol) of 2-benzylthio-5,7-dichloro-1,2,4-triazolo[1,5-a]pyrimidine in 12.5 ml (213 mmol) of acetic acid, 50 ml of methanol and 300 ml of tetrahydrofuran was added 20.5 g of Zn-Cu couple. The mixture was stirred overnight at 22°-23° C. When the reaction was complete (TLC analysis) the reaction mixture was filtered through celite and the filtrate was concentrated by evaporation at reduced pressure. The residue was triturated with hexane to separate a solid. The solid was collected by filtration to yield the desired product as 26.5 g (92%) of orange solid, m.p. 125°-127° C. IR and 1H NMR spectra were in agreement with the assigned structure.

Provenance & Evidence