“…The syntheses of 9-(5-(piperidylcarbamothioyl)thiophen-2-yl)-2,3,6,7,12,13,16,17-octahydro-[1 H ,5 H ,11 H ,15 H ]-10-selenoxantheno[2,3,4-ij:5,6,7-i′j′]diquinolizin-18-ium chloride ( 5 ) and 9-(5-(piperidylcarbamoyl)thiophen-2-yl)-2,3,6,7,12,13,16,17-octa-hydro[1 H ,5 H ,11 H ,15 H ]-10-selenoxantheno-[2,3,4-ij:5,6,7-i′j′]diquinolizin-18-ium chloride ( 6 ) have been previously described 19 and a similar synthetic approach was employed for the synthesis of 7 – 10 . Xanthones 11 and 12 were prepared as previously described.…”