Six new N-substituted quinazolinones were synthesized and evaluated for their adenosine antagonistic activity using allergic mice model where 1, 3-dibenzyl and 1, 3-dibutyl-quinazolindiones were found to be potent than 1, 3-dimethylanalogues. They were not significant in controlling the neutrophil and lymphocyte count but effective in controlling the eosinophil influx. In adenosine receptor binding studies, 1,3-dimethyl and 1,3-dibutyl derivatives were found to have significant adenosine A1 receptor binding efficiency with Ki values 9nM and 10nM, respectively, while 1,3- dibenzyl-quinazolinone was found to have significant binding to adenosine A2A receptor showing the influence of alkyl and aralkyl groups present in these compounds. Thus, the present work indicates the possibility to explore quinazolindiones as adenosine receptor ligands.

Several investigations were carried on the modification of tacrine (THA), an acetyl cholinesterase inhibitor, used in the treatment of Alzheimer's disease. THA can be prepared by several methods, among those Friedlander condensation is the simplest and convenient approach. As an attempt to synthesize tacrine analogues with less/no hepatotoxicity, we designed some novel thienopyridine derivatives by incorporating terpenoids into the structure. From the designed series, we synthesized three tetracyclic THA analogues by conventional and microwave methods using different catalysts in the presence/absence of solvent. We found the formation of byproducts and some charged species along with desired THA analogues. The reaction mixture was subjected to LC-MS and the title compounds were confirmed. Promising yields were found with anhydrous aluminum chloride in dichloroethane.