| abstract |
Novel 3 - chloro - 1,2,5 - thiadiazole - 4-carboxylic acid is prepared by heating 3-chloro - 4 - cyano - 1,2,5 - thiadiazole with a strong mineral acid. Preferably the reaction is carried out by heating with sulphuric acid at 75-100 DEG C. in aqueous solution. Heating the 4-carboxylic acid at a temperature of at least 130 DEG C. yields 3-chloro-1,2,5-thiadiazole. |