Structural, electronic, and spectroscopic study on 1,5-methanoazocino[4,3-b]indole synthesized by TFB-based route

Abstract

This work proposed a new route to synthesizing pharmaceutical important molecules just in three steps. This synthetic route provides an economical way for synthetic chemistry to get the key products concerning the biochemical importance economically including the monoterpene alkaloids, uleine, tubifolidine. This route involves ring closure and the reaction also involved a cyclization reaction tetrahydrocarbazole with an amine side chain at the C-2 position, and this cyclization was mediated by tetrafluoro-1,4-benzoquinone (TFB). In proposed TFB-based route, (4) (2-(2,3,4,9-tetrahydro-1H-carbazol-2-yl)ethan-1-amine), (5) 2,3,4,5,6,7-hexahydro-1H-1,5-methanoazocino[4,3-b]indole, (6) methyl (1R,5S)-1,3,4,5,6,7-hexahydro-2H-1,5-methanoazocino[4,3-b]indole-2-carboxylate, (7) methyl (1R,5S)-6-oxo-1,3,4,5,6,7-hexahydro-2H-1,5-methanoazocino[4,3-b]indole-2-carboxylate compounds were synthesized and characterized by FTIR and NMR (1H and 13C) spectroscopic tools. Besides, the essential intramolecular interactions, chemical reactivity behavior, and the optical property of (7) as a final production of this work have been investigated by NBO, FMO, and NLO analyses, respectively, and the theoretical calculations were performed by both the B3LYP and M06-HF at 6–311 + G(d,p) basis set.