Efficient synthesis of 2-alkylidene-3-iminoindoles, indolo1,2-bisoquinolin5-ones, delta-carbolines, and indirubines by domino and sequential reactions of functionalized nitriles

摘要

The sodium hydride mediated cyclization of arylacetonitriles with oxalic acid bis(imidoyl) dichlorides, azaanalogues 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-lactarnization" reaction of bis(imidoyl) chlorides with methyl 2-(cyanomethyl)benzoate was developed. This process allowed a convenient one-pot synthesis of indolo1,2-bisoquinolin-5-ones related to tryptanthrin. A new and convenient synthesis of delta-carbolines by intramolecular electrocyclization elimination reactions of 2-alkylidene-3-iminoindoles was developed. It was shown that delta-carbolines selectively bind to triplex or duplex DNA (intercalation). Indirubine analogues were prepared by deprotection and lactonization of functionalized 2-alkylidene-3-iminoindoles. References: 60