ABSTRACT
Therapeutic interventions are being developed for Huntington's disease (HD), a hallmark of which is mutant huntingtin protein (mHTT) aggregates. Following the advancement to human testing of two [11C]-PET ligands for aggregated mHTT, attributes for further optimization were identified. We replaced the pyridazinone ring of CHDI-180 with a pyrimidine ring and minimized off-target binding using brain homogenate derived from Alzheimer's disease patients. The major in vivo metabolic pathway via aldehyde oxidase was blocked with a 2-methyl group on the pyrimidine ring. A strategically placed ring-nitrogen on the benzoxazole core ensured high free fraction in the brain without introducing efflux. Replacing a methoxy pendant with a fluoro-ethoxy group and introducing deuterium atoms suppressed oxidative defluorination and accumulation of [18F]-signal in bones. The resulting PET ligand, CHDI-650, shows a rapid brain uptake and washout profile in non-human primates and is now being advanced to human testing.
Subject(s)
Huntington Disease , Positron-Emission Tomography , Animals , Humans , Huntingtin Protein/genetics , Huntingtin Protein/metabolism , Ligands , Positron-Emission Tomography/methods , Huntington Disease/diagnostic imaging , Huntington Disease/drug therapy , Brain/diagnostic imaging , Brain/metabolismABSTRACT
We describe herein the discovery and development of a series of 4-arylthieno[3,2-d]pyrimidines which are potent adenosine A(2A) receptor antagonists. These novel compounds show high degrees of selectivity against the human A(1), A(2B) and A(3) receptor sub-types. Moreover, a number of these compounds show promising activity in vivo, suggesting potential utility in the treatment of Parkinson's disease.
Subject(s)
Adenosine A2 Receptor Antagonists , Antiparkinson Agents/therapeutic use , Drug Design , Parkinsonian Disorders/drug therapy , Pyrimidines/therapeutic use , Adenosine A1 Receptor Antagonists , Adenosine A3 Receptor Antagonists , Antiparkinson Agents/chemical synthesis , Humans , Models, Chemical , Pyrimidines/chemical synthesis , Stereoisomerism , Structure-Activity RelationshipABSTRACT
The (-)-(11R,2'S)-enantiomer of the antimalarial drug mefloquine has been found to be a reasonably potent and moderately selective adenosine A(2A) receptor antagonist. Further investigation of this compound has led to the discovery of a series of keto-aryl thieno[3,2-d]pyrimidine derivatives, which are potent and selective antagonists of the adenosine A(2A) receptor. These derivatives show selectivity against the A(1) receptor. Furthermore, some of these compounds have been shown to have in vivo activity in a commonly used model, suggesting the potential for the treatment of Parkinson's disease.
