Phosphine Supported Ruthenium Nanoparticle Catalyzed Synthesis of Substituted Pyrazines and Imidazoles from α-Diketones.

J Org Chem

Institute of Chemical Research of Catalonia (ICIQ), The Barcelona Institute of Science and Technology, Av. Països Catalans 16, 43007 Tarragona, Spain.

Published: February 2017


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Article Abstract

A new methodology has been developed for the synthesis of highly substituted nitrogen heterocycles such as pyrazines and imidazoles starting from α-diketones using phosphine supported ruthenium nanoparticles (RuNPs) as catalysts. Ruthenium nanoparticles Ru1-Ru4 supported with different phosphines such as dbdocphos, dppp, DPEphos, and Xantphos are screened, of which Ru1 and Ru4 are found to be the most active. Interestingly, aryl-substituted and alkyl-substituted α-diketones produced different products: namely, pyrazine and imidazoles, respectively. This reaction methodology has been applied to the synthesis of a key intermediate (2m) of the marine cytotoxic natural product Dragmacidin B and an estrogen receptor (2l). This work represents the first examples of pyrazines prepared by RuNPs.

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http://dx.doi.org/10.1021/acs.joc.6b03032DOI Listing

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