Some different demethylation products and the double bond isomer of 2-bromo-4-[1-eth-(E)- ylidene-2-(4-methoxy-phenyl)-butyl]-1-methoxy-benzene (3) were obtained under different conditions dur-ing synthesizing 3’-methoxyl-1,2-diethystilbestrol (2). The angiogenesis inhibitory activities of some com-pounds were evaluated on human umbilical vein endothelial cells and the assay data indicated that the groups substituted on the skeleton of diethystilbestrol analogs could significantly affect their anti-angiogenesis activities.

Key words: 2-bromo-4-[1-eth-(E)-ylidene-2-(4-methoxy-phenyl)-butyl]-1-methoxy-benzene, isomerisation of double bond reaction, angiogenesis inhibitor, demethylation reaction