Synthesis and in vitro cytotoxicity of a series of 3-aminoflavones

To further understand the molecular requirements for the antiproliferative activity of flavonoids, a series of 3-aminoflavones and some of their derivatives were prepared and evaluated using L1210 murine leukemia. Our novel five-step synthetic approach required easily available substituted aromatic aldehydes as starting materials and proved more convenient and more general than previously reported methods. Our results in the 3-aminoflavones series indicated that the 4'-methoxy group is important for cytotoxic activity. Moreover, for the flavone-8-acetic analogs, a marked increase in potency was observed with the addition of a 3-amino or a 3-nitro group, Methoxy groups on the 6 and 7 positions of flavonoids (as in cirsiliol) also appear to be important for antiproliferative activity. These results are essential for the further understanding of the critical molecular requirements that lead to antiproliferative properties in the flavonoid series.