Design and Synthesis of New Quinazolin-4-one Derivatives with Negative mGlu(7) Receptor Modulation Activity and Antipsychotic-Like Properties

Following the glutamatergic theory of schizophrenia and based on our previous study regarding the antipsychotic-like activity of mGlu(7) NAMs, we synthesized a new compound library containing 103 members, which were examined for NAM mGlu(7) activity in the T-REx 293 cell line expressing a recombinant human mGlu(7) receptor. Out of the twenty-two scaffolds examined, active compounds were found only within the quinazolinone chemotype. 2-(2-Chlorophenyl)-6-(2,3-dimethoxyphenyl)-3-methylquinazolin-4(3H)-one (A9-7, ALX-171, mGlu(7) IC(50) = 6.14 µM) was selective over other group III mGlu receptors (mGlu(4) and mGlu(8)), exhibited satisfactory drug-like properties in preliminary DMPK profiling, and was further tested in animal models of antipsychotic-like activity, assessing the positive, negative, and cognitive symptoms. ALX-171 reversed DOI-induced head twitches and MK-801-induced disruptions of social interactions or cognition in the novel object recognition test and spatial delayed alternation test. On the other hand, the efficacy of the compound was not observed in the MK-801-induced hyperactivity test or prepulse inhibition. In summary, the observed antipsychotic activity profile of ALX-171 justifies the further development of the group of quinazolin-4-one derivatives in the search for a new drug candidate for schizophrenia treatment.