Design, synthesis and diversification of natural product-inspired hydantoin-fused tetrahydroazepino indolesElectronic supplementary information (ESI) available: Full spectroscopic data (1H and 13C NMR, LRMS, HRMS, FT-IR, chiral HPLC) for compounds 7a-7s and X-ray crystallographic data of compound 5, 7b and 7r are included in the SI file. Their DAO enzymatic assay, inhibition screening on porcine kidney DAO and IC50 data are attached. CCDC 1033162, 1028024 and 1027211. For ESI and crystallographi

A facile and efficient synthesis of novel oxo, thio and seleno hydantoin fused tetrahydroazepino [4,5- b ]indoles was reported. A naturally occurring iboga class alkaloid inspired seven-membered azepino[4,5- b ]indole ring was synthesized as a new scaffold through Pictet-Spengler reaction followed by skeletal rearrangement of the aziridine ring. To improve the efficiency of the synthetic route, the double bond of the rearranged olefinic product 5 was reduced and a privileged hydantoin moiety was constructed on the core system through urea formation using a variety of isocyanates, isothiocyanates and isoselenocyanates followed by intramolecular cyclization to incorporate elements of diversity. The regeneration of the double bond of intermediate 9 afforded hydantoin-fused tetrahydroazepino [4,5- b ]indoles. A facile and efficient synthesis of novel oxo, thio and seleno hydantoin fused tetrahydroazepino [4,5- b ]indoles was reported.