Hydrochloric Acid → 1,2,4-Thiadiazole-3-carboxylic acid, 5-chloro-, methyl ester

Participants

Reaction Conditions

Reaction Steps

To a mixture of methyl 5-amino-1,2,4-thiadiazole-3-carboxylate (26 g), conc.hydrochloric acid (490 ml) and a small amount of copper was added dropwise over 40 minutes a solution of sodium nitrite (22.5 g) in water (28 ml) at -10° to -15° C. The mixture was stirred for 1.5 hours at the same temperature and for 30 minutes at 50° C. The reaction mixture was poured into ice-water (500 ml) and extracted with ethyl acetate. The extract was washed, dried and concentrated to give white powder of methyl 5-chloro-1,2,4-thiadiazole-3-carboxylate (8.9 g).

Provenance & Evidence