Dihydro-oxazolobenzodiazepinone derivatives (I) are new. Dihydro-oxazolobenzodiazepinone derivatives of formula (I) and their positional isomers, enantiomers, diastereoisomers or addition salts with acids, solvates, complexes or adducts, are new. R1 : H or 1-4C alkyl； R2 : 1-4C alkyl； and R3 : (hetero)aryl. An independent claim is included for the preparation of (I). [Image] ACTIVITY : Neuroleptic； Antidepressant； Neuroprotective； Nootropic； Antiparkinsonian； Anticonvulsant； Tranquilizer； Vulnerary； Cerebroprotective. MECHANISM OF ACTION : gamma -Aminobutyric acid (GABA) receptor agonist. The GABA receptor agonistic activity of (I) was tested in human embryonic kidney (HEK-293) cells. The result showed that 5-(6-fluoro-1-benzothien-2-yl)-8-methyl-1,9-dihydro-2H-[1,3]oxazolo[4,5-h][2,3]benzodiazepin-2-one exhibited an IC 5 0value of 100 nM.
