Abstract:In the present work a series of novel derivatives of 1,3,4-

Schiff Bases of 5-(2-phenoxypyridin-3-yl)-1, 3, 4-thiadiazol-2-aminederivatives 6(a-h) have been synthesized with different aromatic aldehyde and tested for in vitro anticancer activity; the 1, 3, 4-thiadiazole derivatives were prepared by the reaction ofthiosemicarbazide, phosphorousoxychloride and aromatic acids. The synthesized final Schiff base compounds were purified by column-chromatography and the structures of the titled Schiff bases were elucidated by IR, 1 H NMR and LCMS spectral measurements. Three different cell lines namely Hela, Hep-G2 and MCF7 are used for the present study. The compounds tested were, in most of cases shows cytotoxic effect but, only one compound showed good activity on breast carcinoma cell line having IC50 = 2.28 μg/ mL.