Synthesis of some new 2, 5-disubstituted 1,3,4-oxadiazole derivatives and their biological activity

900-9042-(Coumarin-3-y l)-5-aryl-1,3,4-oxadiazole derivatives 3-5 have been synthesised by condensing hydrazide 2 of 3-carbethoxycoumarin with various aromatic acids. Compound 3 is also synthesized by another route involving synthesis of an intermediate N-2-hydroxy benzylidene coumarin-3-carboxyhydrazide 6 which is prepared by reacting 2 with salicy laldehyde. On refluxing it in presence of chloramine T the desired 1,3,4- oxadiazole deri vative 3 is obtained. In another set of experiments, 4- methyl -7- (5-phenyl-1,3,4-oxadiazole-2-yl methoxy) coumarin 10 and 4-methyl-7-(5-amino- 1,3,4-oxadiazo-2-yl methoxy) coumarin 11 were pre pared by condensing 4-methyl coumarinyl-7-oxyacetic hydrazide 9 with benzoic acid and cyanogen bromide respectively. All the oxadiazole derivatives and the compound 6 have been tested for their antiinflammatory, analgesic and antimicrobial activity with interesting results