Synthesis, binding studies, and structure activity relationships of 1-aryl- and 2-aryl[1]benzopyranopyrazol-4-ones, central benzodiazepine receptor ligands

Benzodiazepines are important therapeutic agents which have been the object intense investigation. These drugs exert their main actions, such as anxiolytic, hypnotic, anticonvulsant, and muscle relaxant effects, on the central nervous system, by interacting with special neuronal membrane proteins, the benzodiazepine receptors, which are at least partly located in GABA-ergic synapses. The authors report the syntheses and binding studies of a series of 1,4-dihydro-1-aryl-3-methyl(1)benzopyrano(3,4-d)-pyrazol-4-ones 1 and a series of 2,4-dihydro-2-aryl-3-methyl(1)benzopyrano(4,3-c)pyrazol-4-ones 2.