Structural study of bioisosteric derivatives of 5-(1-indol-3-yl)-benzotriazole and their ability to form chalcogen bonds.

Recently, inter-est in the isosteric replacement of a nitro-gen atom to selenium, sulfur or oxygen atoms has been highlighted in the design of potential inhibitors for cancer research. In this context, the structures of 5-(1-indol-3-yl)-2,1,3-benzotriazole derivatives [5-(1-indol-3-yl)-2,1,3-benzo-thia-diazole (bS, CHNS) and 5-(1-indol-3-yl)-2,1,3-benzoxa-diazole (bO, CHNO)], as well as a synthesis inter-mediate of the selenated bioisostere [5-[1-(benzensulfon-yl)-1-indol-3-yl]-2,1,3-benzoselena-diazole (p-bSe, CHNOSSe)] were determined using single-crystal X-ray diffraction (SCXRD) analyses. Despite being analogues, different crystal packing, torsion angles and supra-molecular features were observed, depending on the substitution of the central atoms of the benzotriazole.