[Studies on synthesis and anticonvulsant activity of 3-GABA derivatives of 6-(substituted-phenyl) pyridazines].

In recent years considerable emphasis has been placed on the hypothesis that enhancement of GABA transmission could be beneficial in some types of epilepsy. The alpha-(aryl)-4-morpholineacetonitrile obtained by the interaction of aryl aldehydes, morpholine and potassium cyanide, have been used to synthesize 3-(aroyl)-propionic acids and esters by 1,4-additions to acrylonitrile or acrylic ester. 3-(Aroyl) propionic acids reacting with hydrazine can yield 6-aryl-4,5-dihydro-3(2H) pyridazinones which are dehydrogenated by bromine (via bromination dehydrobromination) to give 6-aryl-3(2H) pyridazinones. The latter compounds were converted into 3-(N-GABA)-6-(substitutedphenyl) pyridazines and 3-(N-butyryllactamyl)-6-(substitutedphenyl) pyridazines by the chlorination (by means of phosphorus oxychloride) and then reaction with GABA. By this method seventeen 3-GABA derivatives of 6-(substituted-phenyl)pyridazines were synthesized. The anticonvulsant activity (MES) of these compounds were also tested. 3-(N-GABA)-6-(2',4'-dichloro)phenylpyridazine; potent anticonvulsant (ED50 = 21.05 mg/kg).