METHOD FOR PREPARING 5-CHLORO-4-AMINO-SUBSTITUTED DERIVATIVE OF 3(2H)-PYRIDAZINONE Russian patent published in 2003 - IPC

FIELD: organic chemistry, chemical technology, pharmacy. SUBSTANCE: invention relates to a novel method for preparing 5-chloro-4-amino-substituted derivative of 3(2H)-pyridazinone of the formula (I) and its pharmaceutically acceptable acidic additive salts. The compound of the formula (I) shows antiarrhythmic properties and prevents ventricular and auricular fibrillations. The proposed method involves reaction of 3,4,5- -trichloropyridazine of the formula (V) with 3-amino-1-propanol and the following interaction of synthesized compound of the formula (IV) with agent suitable for incorporation of a lower alkanoyl group and interaction of synthesized compound of the general formula (III) where R means lower alkanoyl with agent incorporating a splitting off halogen group and interaction of synthesized compound of the general formula (II) where X means halogen atom with compound of the formula (VI) and if necessary the conversion of synthesized compound of the formula (I) to its acidic additive salt. Invention relates also to novel intermediate compounds of formulas (IV), (III) and (II). Invention provides the enhancement of regioselectivity of process in preparing compound of the formula (I). EFFECT: improved preparing method. 18 cl, 5 ex