Appearance of the original drug is gray-white crystals, specific gravity 1.44 (20C), melting point 181-182C, 20C vapor pressure 0.0147mPa (20C); solubility (20C): in water, hexane, chloroform, benzene, acetone solubility of 1.45*10-2g/l, 0.2g/L, 234.4g/L, 15.6g/L. 31.7g/L. The original content of active ingredients is less than 98%, stable storage under normal conditions, 31.7g/L. The content of the original active ingredient is not less than 98%, and the storage is stable under normal conditions.
Industrial production of pyrazosulfuron is usually as the ethyl variant and typically begins with synthesis of the substituted pyrazole core, often through condensation of a beta-ketoester with hydrazine derivatives, followed by chlorination or activation at the appropriate position to enable later coupling. In parallel, the sulfonamide fragment is prepared by reacting a chlorosulfonyl intermediate with a selected amine to generate the sulfonyl chloride or sulfonamide precursor. These two components are then united through formation of the sulfonylurea bridge, usually by treating the sulfonamide with an isocyanate or carbamoyl-activating reagent and subsequently coupling it to the activated pyrazole moiety. After the key bond forming step, the crude product is purified by crystallization or solvent washing to remove unreacted materials and by-products.
