Synthesis and Cytotoxicity of Novel Indoloquinolines and Benzonaphthyridines from 4-Chloro-2,8-dimethylquinoline and Variety of Hetero Amines

Abstract

The synthesis of hetero substituted indoloquinolines and thiophene substituted benzonaphthyridienes from two heterocycles tethered by nitrogen or sulfur intermediates. Further it was cyclized using Pd(OAc)2 catalyst to yield products, i. e., various heteroindolo quinolines and polyphosphoric acid (PPA) mediated thiophene substituted naphthyridines. All the potential intermediates and their respective final products were screened for anticancer activity against HeLa and K562 cancer cells, and it showed good cytotoxicity against HeLa and K562 cells compared standard Adriamycin (ADR) drugs. Among the newly synthesized compounds, compounds 3 a, 3 b, 4 b and 5 a displayed stronger cytotoxic activity against both HeLa and K562 cells compared standard Adriamycin (ADR) drug. This might be due to the presence of benzothiazole and isoquinoline moieties, which enhanced the cytotoxic activity. Subsequently, compounds 3 c, 3 d, 4 a, 5 b and 7 also showed better cytotoxic activity with IC50 values <19 μM against HeLa and K562 cells, which was due to the presence of quinoline and thiophene moieties, which enhanced the cytotoxic activity.