5728-20-1

Colorless liquid

3,4-Dichloro-1,2,5-thiadiazole is a chlorinated thiadiazole that is a potent inhibitors of nitrification in soil. 3,4-Dichloro-1,2,5-thiadiazole is used as a building block in the preparaton of the β-adrenergic blocking agent, Timolol (T443700).

Tetrahedron Letters, 15, p. 1687, 1974 DOI: 10.1016/S0040-4039(01)82554-5

GENERAL PROCEDURE: The reaction system was cooled to -25°C under argon protection, followed by the slow dropwise addition of disulfur dichloride (S2Cl2, 0.64 mL, 8.00 mmol) to a solution of anhydrous acetonitrile (10 mL) containing o-dichloroacetaldioxime (2.0 mmol) and pyridine (0.80 mL, 10.0 mmol) while stirring was maintained. After dropwise addition, the reaction mixture was gradually warmed to room temperature and continued stirring for 1 hour, followed by heating to reflux state for 4 hours. Upon completion of the reaction, the mixture was filtered to remove insoluble material and the filtrate was concentrated under reduced pressure to remove solvent. The resulting crude product was purified by column chromatography (silica gel Merck 60, eluent was a solvent mixture of hexane/dichloromethane) to afford the target product 3,4-dichloro-1,2,5-thiadiazole.

[1] Tetrahedron, 2014, vol. 70, # 35, p. 5558 - 5568
[2] Journal of Organic Chemistry, 1970, vol. 35, p. 1165 - 1169