METHOD FOR PREPARING 5-CHLORO-4-[(2-IMIDAZOLINE-2-YL)AMINO]-2,1,3-BENZOTHIADIZOLE Russian patent published in 2004 - IPC

FIELD: organic chemistry, chemical technology.

SUBSTANCE: invention relates to a method for preparing 5-chloro-4-[(2-imidazoline-2-yl)amino]-2,1,3-benzothiadiazole (I). Method involves interaction of 5-chloro-4-amino-2,1,3-benzothiadiazole (II) with 1-acetyl-2-imidazolidone (II) in phosphorus oxychloride medium at temperature 50-60^oC followed by distilling off phosphorus oxychloride excess, treatment of residue with water, alkalization of an aqueous solution with sodium hydroxide, isolation of interaction product from reaction mixture and its hydrolysis with sodium hydroxide in an aqueous-methanol mixture, the following distilling off methanol, cooling residue, filtering and drying the precipitated end product. 1-Acetyl-2-imidazolidone is treated preliminary with phosphorus oxychloride at 25-30^oC and the following addition of 5-chloro-4-amino-2,1,3-benzothiadiazole to reaction mass. The interaction product is isolated by treatment of an aqueous solution with activated carbon, alkalization of cleared solution and filtering and then the isolated product is subjected for hydrolysis as an aqueous paste. The yield of product is 81% as measured for compound (II) with mass part of the main substance 98.5%, not less, and melting point 219-222^oC. Invention provides simplifying method, reducing energy consumption, high yield and quality of the end product.

EFFECT: improved preparing method.

1 ex