New propargyl thioquinolines--synthesis, antiproliferative activity in vitro and structure-activity relationships.

The series of the propargyl thioquinolines has been prepared on the basis of the reaction of thioquinanthrene (1) (1,4-dithiino[2,3-c:5,6-c']-diquinoline) with sodium alkoxides. Some of these compounds have revealed good antiproliferative activity in vitro against the cells of human and murine cancer lines. 13 C NMR spectra were measured for the studied compounds to examine the electronic properties-activity relationships. A regression study on 10 compounds showed a linear correlation of antiproliferative activity with electronic properties, expressed as the 13 C NMR chemical shift for C-4 carbon atom (R 2 = 0.97). It was found that compounds with chemical shift for C-4 value falling in the range of 135-140 ppm exhibited significant antiproliferative activity, while compounds which possess moderate or low activity are located in the range 140-165 ppm. This finding leads to the expectation that the antiproliferative activity of propargyl thioquinolines can be predicted using the 13 C NMR chemical shift value of their C-4 carbon atom.