METHOD FOR PRODUCING PHTALAZOL Russian patent published in 2019 - IPC C07D277/52 C07B63/04 

FIELD: organic chemistry.

SUBSTANCE: invention relates to organic chemistry and is a method of producing phthalazol, according to which reaction mass from purified water, sodium hydroxide and technical phthalazole is heated to 60 ± 10 °C further maintenance for 10–30 minutes, active coal is added and heated to 60 ± 10 °C with subsequent exposure for 20–40 minutes, adding sodium hydrosulfite and acetic acid to pH 4–6, after washing and wringing out a paste of phthalazole with content of chlorides of not more than 0.01 % and sulphates of not more than 0.025 % and drying at temperature of 90 ± 30 °C, characterized by that when producing technical phthalazole, commercial phthalic acid is used or synthesized by dissolving phthalic anhydride in water while heating, followed by acylation of norsulphazole with phthalic acid, at that, after curing, reaction mass is filtered through another filter into reactor, in reactor reaction mass is heated to 60 ± 10 °C, then loading sodium bisulphite and stirring for 10–20 minutes, and after termination of drying sample is taken to determine percentage of moisture, which should not be more than 1.6 %.

EFFECT: invention provides a wider range of pharmacopoeial phthalazole-producing agents.

1 cl