PYRIDAZINE DERIVATIVE INHIBITOR, METHOD OF ITS PREPARATION AND ITS USE Russian patent published in 2023 - IPC C07D401/12 C07D403/12 C07D405/14 C07D409/14 C07D413/14 A61K31/444 A61K31/501 A61P29/00 A61P37/00 

FIELD: pharmaceuticals.

SUBSTANCE: invention relates to an inhibitor that is a pyridazine derivative, namely a compound of formula (V), its stereoisomer or a pharmaceutically acceptable salt thereof, where R₉ is C_3-6 cycloalkyl, R is C_1-6 alkoxy, R₃ is selected from a group consisting of hydrogen and halogen, R₄ is cyclopropyl, R₅ and R₆ are hydrogen, x is either 0 or 1. The invention also relates to a method of producing a compound of formula (V), to a pharmaceutical composition containing it and to its use for the production of a TYK2 inhibitory medicinal product for the treatment of an inflammatory disease and an autoimmune disease, wherein the inflammatory disease and the autoimmune disease are selected from the group consisting of rheumatoid arthritis, dermatitis, psoriasis and inflammatory bowel disease.

EFFECT: development of a safer selective TYK2 inhibitor for the treatment of inflammatory and autoimmune diseases.

10 cl, 1 dwg, 121 ex, 5 tbl