METHOD FOR PREPARATION OF 4-AMINOPYRIDINES Russian patent published in 2022 - IPC C07D237/20 C07D403/12 

FIELD: organic chemistry.

SUBSTANCE: group of inventions relates to organic chemistry and includes a method for obtaining dichloropyridazinamine compounds of formulas IVa, IVb, or mixtures thereof, a method for obtaining a pyridazinamine compound of formula V, or its salt, or tautomer, a method for obtaining a compound of formula VII, or its stereoisomer, or salt, or tautomer, as well as a mixture of intermediate dichloropyridazinamine compounds of formulas IVa and IVb for the preparation of a pyridazinamine compound of formula V. A method for producing (a) a dichloropyridazinamine compound of formula IVa, or its salt, or tautomer, or (b) a dichloropyridazinamine compound of formula IVb, or its salt, or tautomer, or (c) a mixture of (a) and (b) involves the interaction of a compound of formula III with ethylamine or its salt. The method additionally does not necessarily include a stage of obtaining a trichloropyridazine compound of formula III by reacting a compound of formula II with POCl₃. The method for obtaining a pyridazinamine compound of formula V, or its salt, or tautomer, includes a stage for obtaining a dichloropyridazinamine compound of formula IVa, or IVb, or their salt, or tautomer, or a mixture, by the above method. Then, (a) the dichloropyridazinamine compound of formula IVa, or its salt, or tautomer, or (b) the dichloropyridazinamine compound of formula IVb, or its salt, or tautomer, or (c) a mixture of (a) and (b) interact with hydrogen in the presence of a hydrogenation catalyst to obtain a compound of formula V. A method for obtaining a compound of formula VII, or its stereoisomer, or salt, or tautomer, involves the interaction of a compound of formula V, or its salt, or tautomer obtained by the above method, with a compound of formula VI, or its stereoisomer, or salt, or tautomer. In compounds of formulas IVa, IVb, V and VII, R¹ is CH₂CH₃. In compounds of formulas VI, VII, the substituents R², R³, R^N, X¹ are as indicated in the claims.

EFFECT: an improved method for obtaining intermediate compounds of dichloropyridazinamine formulas IVa, IVb, or mixtures thereof, with high yields, using ethylamine as a nucleophile, carried out at a reaction temperature of no more than 100°C and reaction time of no more than 12 hours.

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12 cl, 2 ex