Synthesis and antiproliferative properties of N3/8-disubstituted3,8-diazabicyclo[3.2.1]octane analogues of 3,8-bis[2-(3,4,5-trimethoxyphenyl)pyridin-4-yl]methyl-piperazine

A series of novel N(3/8)-disubstituted-3,8-diazabicyclo[3.2.1]octanes in order to improve the in vitro activity of the prototype 3,8-bis[2-(3,4,5-trimethoxyphenyl)pyridyl-4-yl)methylpiperazine (1) were synthesized and evaluated by assays of growth inhibition against several tumor cell lines. Compounds 2a,b,f and m demonstrated not only growth-inhibitory activities against leukemia cancer cells, but also fairly good activities against the growth of certain solid tumors. Among them, 2a is the most potent one with IC(50) values in the low micromolar range. Moreover, compound 2a has been selected for in vitro testing on MCF-7 cell to evaluate the mode of action of this lead compound.