Selective reduction of condensed N-heterocycles using water as a solvent and a hydrogen source

Organic & Biomolecular Chemistry Pub Date: 2012-12-14 DOI: 10.1039/C2OB26903A

Abstract

The reduction of unprotected indoles and quinolines is described using water as a hydrogen source. The method is based on the application of a RANEY? type Ni–Al alloy in an aqueous medium. During the reaction the Al content of the alloy, used as reductants, reacts with water in situ providing hydrogen and a RANEY? Ni catalyst, thus the alloy serves as a hydrogen generator as well as a hydrogenation catalyst. The simplicity and efficacy of the method are illustrated by the selective reduction of a variety of substituted indoles and quinolines to indolines and tetrahydroquinolines, respectively.

Graphical abstract: Selective reduction of condensed N-heterocycles using water as a solvent and a hydrogen source
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