2-Amino-5-bromo-1,3,4-thiadiazole → 2-Bromo-5-nitro-1,3,4-thiadiazole

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Reaction Steps

To a stirred solution of NaNO2 (116 g, 1.68 mol) in water (1200 mL) was added copper metal powder (72 g, 1.12 mol) and 1.2 mL conc. HCl. Thereafter, 5-bromo-1,3,4-thiadiazol-2-amine (100 g, 0.56 mol) was warmed to dissolve in 4 M aq. HCl (120 mL) and added potionwise. The mixture was stirred at r.t. for 3 hrs. The precipitated yellow solid was filtered and washed with water. The solid was dissolved in ether, filtered and the filtrate concentrated in vacuo to give 2-bromo-5-nitro-[1,3,4]thiadiazole (57 g, 88% purity in HPLC, 48% yield).

Provenance & Evidence