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Efficient Synthesis of 2‐Alkylidene‐3‐iminoindoles, Indolo[1,2‐ b ]isoquinolin‐5‐ones, δ ‐Carbolines, and Indirubines by Domino and Sequential Reactions of Functionalized Nitriles
Author(s) -
Langer Peter,
Anders Joachim T.,
Weisz Klaus,
Jähnchen Judith
Publication year - 2003
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.200204566
Subject(s) - chemistry , oxalyl chloride , sodium hydride , selectivity , medicinal chemistry , domino , combinatorial chemistry , intramolecular force , cascade reaction , organic chemistry , catalysis
Abstract The sodium hydride mediated cyclization of arylacetonitriles with oxalic acid bis(imidoyl) dichlorides, aza‐analogues of oxalyl chloride, afforded functionalized 2‐alkylidene‐3‐iminoindoles with very good regio‐ and E / Z selectivity. Excellent chemoselectivities were observed for functionalized substrates. Based on these results a domino “cyclization–lactamization” reaction of bis(imidoyl) chlorides with methyl 2‐(cyanomethyl)benzoate was developed. This process allowed a convenient one‐pot synthesis of indolo[1,2‐ b ]isoquinolin‐5‐ones related to tryptanthrin. A new and convenient synthesis of δ ‐carbolines by intramolecular electrocyclization–elimination reactions of 2‐alkylidene‐3‐iminoindoles was developed. It was shown that δ ‐carbolines selectively bind to triplex or duplex DNA (intercalation). Indirubine analogues were prepared by deprotection and lactonization of functionalized 2‐alkylidene‐3‐iminoindoles.