Isoindolinone compounds and imaging agents for imaging Huntingtin protein

1 . A compound that is:

or an isotopically enriched analog, pharmaceutically acceptable salt, tautomer, stereoisomer, or a mixture of stereoisomers thereof, optionally wherein the compound is labeled with a radioactive isotope.

2 . The compound of claim 1 , wherein the compound is labeled with a radioactive isotope.

3 . The compound of claim 2 , wherein the compound contains a positron-emitting radioactive isotope selected from 11 C, 13 N, 15 O, and 18 F.

4 . An imaging agent comprising the compound of claim 2 , or an isotopically enriched analog, pharmaceutically acceptable salt, tautomer, stereoisomer, or a mixture of stereoisomers thereof.

5 . A method of detecting a presence or absence of a protein susceptible to aggregation in an individual comprising administering an effective amount of the imaging agent of claim 4 to the individual, and generating an image of a body part or body area of the individual.

6 . The method of claim 5 , wherein the presence or absence of a protein aggregate corresponds to a presence or absence of a neurodegenerative disease.

7 . The method of claim 6 , wherein the neurodegenerative disease is selected from Alzheimer's disease, amyotrophic lateral sclerosis, Huntington's disease, Parkinson's disease, Prion disease, and spinocerebellar ataxias.

8 . The method of claim 7 , wherein the neurodegenerative disease is Huntington's disease (HD).

9 . The method of claim 5 , wherein generating an image comprises positron emission tomography (PET) imaging, PET with concurrent computed tomography imaging (PET/CT), PET with concurrent magnetic resonance imaging (PET/MRI), single-photon emission computed tomography (SPECT) imaging, or a combination thereof.

10 . The method of claim 9 , wherein generating an image comprises PET imaging.