Synthesis, structure, ionochromic and cytotoxic properties of new 2-(indolin-2-yl)-1,3-tropolones.

The acid-catalyzed reaction of benzo[()] derivatives of 2,3,3-trimethylindolenines with -chloranil leads to new 2-(benzo[()]indolin-2-yl)-5,6,7-trichloro-1,3-tropolones and 2-(benzo[()]indolin-2-yl)-4,5,6,7-tetrachloro-1,3-tropolones. Based on the results of PBE0/6-311+G(d,p) calculations, the structural and energetic characteristics of the tautomeric forms of the obtained 1,3-tropolones were determined. The structure of 2-(3,3-dimethyl-3-benzo[]indolin-2-yl)-5,6,7-trichloro-1,3-tropolone was determined by X-ray diffraction analysis. The compounds obtained are capable of switching emission at 420-440 nm and 476-530 nm upon successive exposure to CN and Hg ions in an acetonitrile solution. 2-(1,1-Dimethyl-1-benzo[]indolin-2-yl)-5,6,7-trichloro-1,3-tropolone exhibited high in vitro cytotoxic activity against A431 skin cancer and H1299 lung cancer cell lines.