Multigram Scale Synthesis and Anti-Influenza Activity of 3-Indoleacetonitrile Glucosides

Indole-3-acetonitrile-6-O-beta-d-glucopyranoside 1 is a simple alkaloid with anti-influenza A virus activity extracted from Radix isatidis. Herein, a concise and practical total synthetic route of 1 was presented, starting from 6-benzyloxyindole on a multigram scale. The pivotal reaction sequence involved the Mannich reaction, the fluoride ion-induced elimination-addition reaction, and phase-transfer-catalyzed glycosylation reaction as key steps. In addition, compounds 1 and two modified derivatives 8 and 16 were tested for anti-influenza efficacy and cytotoxicity in vitro performed on Madin-Darby canine kidney cells. The results revealed that the compounds exerted antiviral activity against the influenza A virus to a certain extent and displayed no cytotoxicity. These findings could contribute to the development of traditional Chinese medicine R. isatidis for treating the influenza virus.