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

Abstract

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