Nucleophilic Substitution of Hydrogen in Arenes and Heteroarenes

SNH Amidation of 5-Nitroisoquinoline: Access to Nitro- and Nitroso Derivatives of Amides and Ureas on the Basis of Isoquinoline

For the first time, amides and ureas based on both 5-nitroisoquinoline and 5-nitrosoisoquinoline were obtained by direct nucleophilic substitution of hydrogen in the 5-nitroisoquinoline molecule. In the case of urea and monosubstituted ureas, only 5-nitrosoisoquinoline-6-amine is formed under anhydrous conditions.

Transition-metal-free [3 + 3] annulation of indol-2-ylmethyl carbanions to nitroarenes. A novel synthesis of indolo[3,2-b]quinolines (quindolines)

Indol-2-ylmethyl carbanions stabilized by alkoxycarbonyl, cyano or benzenesulfonyl groups react with nitroarenes to form σ^H-adducts, which in the presence of base (triethylamine or DBU) and trimethylchlorosilane transform into indolo[3,2-b]quinoline derivatives in moderate to good yields.

Metal-Free Sequential C(sp2)-H/OH and C(sp3)-H Aminations of Nitrosoarenes and N-Heterocycles to Ring-Fused Imidazoles

Hydrogen bond assisted ortho-selective C(sp²)-H amination of nitrosoarenes and subsequent α-C(sp³)-H functionalization of aliphatic amines is achieved under metal-free conditions. The annulation of nitrosoarenes and 2-hydroxy-C-nitroso compounds with N-heterocycles provides a facile excess to a wide range of biologically relevant ring-fused benzimidazoles and structurally novel polycyclic imidazoles, respectively. Nucleophilic aromatic hydrogen substitution (S_NArH) was found to be preferred over classical S_NAr reaction during the C(sp²)-H amination of halogenated nitrosoarenes.

Transition-metal-free synthesis of 3-(1-pyrrolidinyl)quinolines and 3-(1-pyrrolidinyl)quinoline 1-oxides via a one-pot reaction of 3-(1-pyrrolidinyl)crotonates with nitrobenzenes

A carbanion of tert-butyl 3-(1-pyrrolidinyl)crotonate adds to nitrobenzenes to form σ^H-adducts, which in the presence of pivaloyl chloride and triethylamine are converted into 3-(1-pyrrolidinyl)quinolines or 3-(1-pyrrolidinyl)quinoline 1-oxides depending on the nitrobenzene structure. This is the first methodology in which a quinoline ring is constructed from a substrate bearing a pyrrolidinyl ring. Starting from optically pure enamines, the method allows synthesis of the corresponding chiral products without racemisation.

Simple synthesis 11-substituted norcryptotackieine derivatives

11-Substituted indolo[2,3-b]quinolines were obtained in reactions ofN-protected indol-3-yl-acetonitrile, -acetate, and -methylsulfone with nitrobenzene derivatives in presence of base and trialkylchlorosilanes.