title: Phosphine Supported Ruthenium Nanoparticle Catalyzed Synthesis of Substituted Pyrazines and Imidazoles from α-Diketones.
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.
authors.affiliation: Institute of Chemical Research of Catalonia (ICIQ), The Barcelona Institute of Science and Technology , Av. Països Catalans 16, 43007 Tarragona, Spain.
authors.forename: Prasad
authors.initials: P
authors.lastname: Ganji
authors.affiliation: Institute of Chemical Research of Catalonia (ICIQ), The Barcelona Institute of Science and Technology , Av. Països Catalans 16, 43007 Tarragona, Spain.|Laboratoire de Physique et Chimie des Nano Objets, LPCNO, UMR5215 INSA-UPSCNRS, Université de Toulouse, Institut National des Sciences Appliquées , 135 Avenue de Rangueil, 31077 Toulouse, France.
authors.forename: Piet W N M
authors.identifier: 0000-0002-2165-7090
authors.initials: PW
authors.lastname: van Leeuwen