| abstract |
An object of the present invention is to provide a probe for the imaging of a protein of the Îmina-ß structure that can be used for the diagnosis of conformational diseases, particularly disease (tautopathy) having a cardinal symptom such as intracerebral accumulation of tau protein, for example, Alzheimer's disease; Another object of the present invention is to provide a compound that is highly specific for tau and can form a tau image with satisfactory sensitivity, and also has high brain transition, low or unrecognized bone search properties and low or unrecognized toxicity. ; In accordance with the present invention, the above problems are solved by providing a compound of a formula I (wherein A, R1, R2, R3, R4, R5, R6, Ra and Rb are as defined in the present description) or a pharmaceutically acceptable salt or solvate thereof. |