Semi-synthesis, structural modification and biological evaluation of 5-arylbenzofuran neolignans†
5-Arylbenzofuran neolignans, a newfound class of natural products, were reported to possess several kinds of pharmacological activities. To solve the lack of natural sources and promote the research of 5-arylbenzofuran neolignans in all fields, an available semi-synthesis methodology of 5-arylbenzofuran neolignans was developed, and a detailed structural modification was conducted. In the meantime, a one-pot process of Waker-type cyclization and Wacker-type oxidation was developed. To explore the potential of 5-arylbenzofuran neolignans as bioactive substances, 5-arylbenzofuran neolignans and their derivatives were evaluated for their cytotoxicity. As a result, a preliminary structure–activity relationship was obtained. Most derivatives revealed low cytotoxic effects suggesting that they were relatively safer than the natural 5-arylbenzofuran neolignan. Several derivatives showed high cytotoxicities which were found to be closely associated with apoptosis-inducing. The selectivity assay for cytotoxicity showed tumor cells were more sensitive to the promising compounds than normal cells.