5-Bromo-benzo[2,1,3]thiadiazole → 5-Cyano-2,1,3-benzothiadiazole

Participants

Reaction Conditions

Reaction Steps

5-Bromobenzo[1,2,5]thiadiazole from Step 1 was dissolved in anhydrous DMF (160 mL) under nitrogen. Then, CuCN (7.27 g, 81 mmol) was added and the mixture was heated to 150° C. overnight. After cooling down, a solution of FeCl3 (19.7 g) in concentrated HCl (7 mL) and water (40 mL) was added dropwise and the mixture was stirred at 70° C. for 30 minutes. After extraction with DCM (200 ml×2), the combined organic phases were extracted with HCl (6M, 100 mL×3), water (100 mL), and brine (100 mL), and dried over MgSO4. Concentration gave a brown solid which was purified by column chromatography with DCM as the eluent. Finally, a white solid was obtained (2.95 g, 65% yield for two steps). 1H NMR (CDCl3 500 MHz): δ: 8.48 (d, 1H, J=1.5 Hz), 8.16 (d, 1H, J=9.0 Hz), 7.75 (dd, 1H, J=9.0, 1.5 Hz).

Provenance & Evidence