Synthesis and in vitro antiproliferative activity of new substituted benzo[3',2':5,6]thiopyrano[4,3-d]pyrimidines.

The synthesis of new planar benzo[3',2':5,6]thiopyrano[4,3-d]pyrimidine derivatives, carrying different side groups in the 2 position, is described. The novel substituted pyrimidines were obtained by reaction of the key intermediate 3-dimethylamino methylen-7-methoxy-2,3-dihydrobenzo[3',2':5,6]thiopyran-4(4H)-one, characterized by a reactive group adjacent to the C=O function, with the suitable binucleophile amidines in a basic medium. All the new compounds were evaluated for the antiproliferative ability by an in vitro assay on two human tumor cell lines (Hl-60 and HeLa), and the 2-phenyl substituted derivative showed the capacity to inhibit cell grow on Hl-60. Linear flow dichroism measurements indicated the inability to form a molecular complex with DNA.