上海科技大学知识管理系统

Indeno[2,1-b]indole and shikimic acid-like structures are natural privileged scaffolds in several bioactive NPs. In this work, we developed a high-efficient and diastereoselective synthetic approach to construct novel indeno[2,1-b]indole/shikimic acid hybrid analogues via photo-Nazarov reaction. The protocol is the first case of excited-state photo-Nazarov cyclization of indole-2-yl vinyl ketone to indeno[2,1-b]indole. (6aS, 10aR)-products were afforded in moderate to good yields (37-92 %) for most of substrates (91 % for model substrate 1 aa) after the condition optimization. Even more attractive, several synthesized analogues (2 t, 3 c and 3 d) exhibited potent RANKL-induced osteoclastogenesis inhibitory activities (inhibitory rate >50 % at 5 mu M), which suggested promising prospect of the novel tetracyclic indeno[2,1-b]indole/shikimic acid hybrid scaffold for anti-osteoporosis drug development.