We discovered a novel compound, 5-methyl-1,4,5,7-tetrahydro-2,5-ethanoazocino[4,3-b]indol-6(3H)-one sulfuric acid salt (DS39201083), which was formed by derivatization of a natural product, conolidine. DS39201083 had a unique bicyclicskeleton and was a more potent analgesic than conolidine, as revealed in the acetic acid-induced writhing test and formalin test in ddY mice. The compound showed no agonist
A total synthesis of indole alkaloids, (±)-conolidine and (±)-apparicine, was accomplished via a gold(I)-catalyzed 6-exo-dig cyclization to construct a piperidine ring bearing an exocyclic (E)-ethylidene appendage.