Synthesis of New Azoles and Azolopyrimidines Incorporating Morpholine Moiety as Potent Anti-Tumor Agents

A new series of morpholinyl-chalcones 2a–d was prepared by reaction of 2-oxo-N,4-diarylbut-3-enehydrazonoyl chlorides 1a–d with morpholine. These chalcones were used as a building block for constructing pyrazoles 3a–d and 3,4-dihydropyrimidine-2(1H)-thione 6 via their reaction with phenylhydrazine and thiourea, respectively. Moreover, a new series of azolopyrimidine derivatives 11a,b, 15, 17, 19, and 21 incorporating morpholine moiety were synthesized by reaction of 1-morpholino-4-phenyl-1-(2-phenylhydrazono)but-3-en-2-one (2a) with a number of heterocyclic amines in the presence of a catalytic amount of acetic acid. The assigned structures for all the newly synthesized compounds were confirmed on the basis of elemental analyses and spectral data and the mechanisms of their formation were also discussed. All the synthesized compounds were tested for in vitro activities against two antitumor cell lines, human lung cancer (A-549) and human hepatocellular carcinoma (HepG-2) compared with the employed standard antitumor drug (cisplatin) and the results revealed that compounds 6, 8c and 17 have promising activities compared with cisplatin.