The invention relates to a
pyridine derivative and a preparation method and application thereof. Specifically, the invention provides a compound shown as a formula I, or a pharmaceutically acceptablesalt, or a
hydrate, or a solvate, or a conformational isomer, or a
crystal form, or an
isotope replacement form thereof, and a preparation method and application thereof. Experimental results show that the
pyridine compound is labeled by
radionuclide and can be used as a
Tau protein tracer agent for identifying neurofibrillar entanglement (NFTs) formed by abnormal aggregation of over-phosphorylated
Tau protein in the brain, and can be used for diagnosing neurofibrillar entanglement related diseases, can also be used for monitoring the progress of the diseases in the treatment process, provideshigher and more accurate diagnosis and tracking for patients with the neurofibrillar entanglement related diseases or potential patients, and has a good application prospect in
clinical diagnosis.