Synthesis and cytotoxicity studies of cyclohepta[b]indoles, benzo[6,7]cyclohepta[1,2-b]indoles, indeno[1,2-b]indoles, and benzo[a]carbazoles

Synthesis and biological evaluation of various tricyclic and tetracyclic indoles are described. A number of these compounds possess in vitro activity against human nasopharyngeal carcinoma (HONE-1) and gastric adenocarcinoma (NUGC-3) cell lines.