37566-39-5

55981-29-8

General procedure for the synthesis of 2,5-dibromo-1,3,4-thiadiazole from 2-amino-5-bromo-1,3,4-thiadiazole: 2-amino-5-bromo-1,3,4-thiadiazole (20 g, 0.111 mol) was slowly added under nitrogen protection to a non-homogeneous mixture containing CuBr2 (29.8 g, 1.2 eq.) and t-BuNO2 (19.8 mL, density = 0.867 g/mL) in a non-homogeneous mixture of MeCN (600 mL, 0.2 M solution), taking care to control the rate of addition to avoid intense exotherm. The reaction mixture was stirred overnight at room temperature. Upon completion of the reaction, the reaction was quenched with 600 mL of saturated aqueous NH4Cl solution and then extracted with ether. The organic layer was dried with MgSO4, filtered and concentrated in vacuum to give the crude product. The crude product was ground in 200 mL MeOH and the solid was collected by filtration to afford the target compound 2,5-dibromo-1,3,4-thiadiazole (18.7 g, 70% yield).