FIELD: pharmacology.SUBSTANCE: invention relates to a new quinoline derivative of formula (I) or a pharmaceutically acceptable salt thereof, wherein A is or , R1 is halogen or , in which R4 and R5 each independently represents hydrogen, a lower alkyl group, or R4, R5 and the nitrogen atom to which they are attached together form a 6-member nitrogen-containing aliphatic ring (where the nitrogen atom may be substituted by a lower alkyl group), or R4 and the nitrogen atom to which it is attached together with ring A form a 10-membered nitrogen-containing fused bicyclic ring (one carbon atom constituting the nitrogen-containing condensed bicyclic ring can be replaced by the oxygen atom), and R5 is a lower alkyl group where a line crossed by a dashed line means a bond of the above general formula with another structural moiety, R2 or R3 each independently represents NRaRb or -O-lower alkyl group (each alkyl group may be substituted with 1 to 2 substituents selected from halogen, hydroxy groups), ring A is unsubstituted or substituted by R6 (where R6 is one substituent selected from halogen and an -O-lower alkyl group (each alkyl group may be substituted with 1 to 2 substituents selected from halogen, hydroxy, Ra and Rb each represents hydrogen or a lower alkyl group, m and n denote an integer from 0 to 1, wherein at least one of R2, R3 and R6 is an -O-lower alkyl group substituted with one hydroxy group and one halogen. The invention also relates to a pharmaceutical composition, a composition for conformational disease diagnosis, treatment or prevention, a diagnostic kit based on a compound of formula (I), a method of treatment, a method for detection or staining of a protein-layer β-structure, a process for preparation of a compound of formula (I) and intermediates.EFFECT: new compounds are obtained that can be used to diagnose and treat conformational diseases, in particular, a disease having such a cardinal symptom as intracerebral accumulation of tau protein, for e
