Study of new developments in birch reduction process and their applications for the synthesis and CNS depressant activity of 3-aminocyclohexa-1,4-diene-1-carboxylic acid and 3-[5-substituted 1,3,4-thiadiazole-2-yl]-2-styryl 5,8-dihydroquinazoline-4 (3H)-ones

Meta nitro benzoic acid has been reduced to 3-aminocyclohexa-1,5-diene-1-carboxylic acid withthree different Birch like reduction condition (Method I, II, III) to 3-aminocyclohexa-1,4-diene-1-carboxylicacid. 3-aminocyclohexa-1,4-diene-1-carboxylic acid is found to be structurally more super impossible ongama-amino butyric acid (GABA) and hence the synthesized compounds was tested for the CNSdepressant and muscle relaxant activities. A series of new 3-[5-substituted phenyl-1,3,4-thiadiazole-2-yl]-2-styryl 5,8-dihydroquinazoline-4 (3H)-ones were synthesized and evaluated for anticonvulsant, sedativehypnoticand CNS depression activities. Various derivatives of 3-[5-substituted phenyl-1,3,4-thiadiazole-2-yl]-2-styryl 5,8-dihydroquinazoline-4 (3H)-ones were examined in the maximal electroshock (MES) inducedseizures and subcutaneous pentylenetetrazole (scPTZ) induced seizure models in mice. Rotorod methodwas employed to determine the neurotoxicity. Out of 9 compounds only 3 compounds showedanticonvulsant activity in one or more test models. All except compound (a) exhibited significant sedativehypnoticactivity via actophotometer screen. Forced swim pool method to determine CNS depressant activityresulted in some potent compounds. It can be concluded that synthesized compounds exhibited bettersedative-hypnotic and CNS depressant activities than anticonvulsant activity.