Entity

Time filter

Source Type

Budapest, Hungary

Pilipecz M.V.,Szent Istvan University | Varga T.R.,Szent Istvan University | Scheiber P.,Szent Istvan University | Mucsi Z.,Szent Istvan University | And 5 more authors.
Tetrahedron | Year: 2012

Using different reducing methods unsaturated indolizidine and quinolizidine lactams substituted with a nitro group were transformed into various alkaloid-like derivatives. Hydrogen transfer and palladium catalyzed hydrogenation gave compounds of ketolactam or lactam type meanwhile the nitro group was eliminated. On the other hand, in presence of Raney-nickel catalyst the nitro compounds were reduced to diastereomeric amino derivatives whose stereochemistry was elucidated by NMR spectroscopy. Using sodium bis-dimethoxy-ethoxy-aluminum-hydride (Red-Al) as reducing agent an unexpected tricyclic azetidine was isolated and characterized. © 2012 Elsevier Ltd. All rights reserved. Source


Pham T.S.,Budapest University of Technology and Economics | Balazs L.,Chinoin Ltd | Petnehazy I.,Budapest University of Technology and Economics | Jaszay Z.,Hungarian Academy of Sciences
Tetrahedron Asymmetry | Year: 2010

An enantioselective Michael addition of diethyl cyanomethyl phosphonate to chalcones catalysed by bifunctional catalysts based on cinchona alkaloids has been developed, producing enantiomerically enriched cyanophosphonate precursors of α-substituted β-aminophosphonates. © 2010 Elsevier Ltd. All rights reserved. Source


Pham T.S.,Budapest University of Technology and Economics | Czirok J.B.,Budapest University of Technology and Economics | Balazs L.,Chinoin Ltd | Pal K.,Hungarian Academy of Sciences | And 4 more authors.
Tetrahedron Asymmetry | Year: 2011

Several novel 1,1′-bi-2-naphthyl-appended azacrown ethers with donor side-arms were synthesized and applied for the first time as chiral catalysts in the asymmetric Michael addition of an N-protected aminomethylenephosphonate onto acrylonitriles, resulting in high diastereoselectivity and enantioselectivity. The absolute configuration of the adduct was determined from its experimental and calculated CD spectra. © 2011 Elsevier Ltd. All rights reserved. Source


Molnar A.,Chinoin Ltd | Molnar A.,Budapest University of Technology and Economics | Kapros A.,Budapest University of Technology and Economics | Parkanyi L.,Hungarian Academy of Sciences | And 3 more authors.
Organic and Biomolecular Chemistry | Year: 2011

The palladium-catalyzed Suzuki-Miyaura cross-coupling reactions of halo derivatives of 4H-pyrido[1,2-a]pyrimidin-4-one with (het)arylboronic acids allow easy access to (het)aryl and vinyl derivatives of this bicycle in good to excellent yields, even from chloro derivatives. The sequence of reactivity of the halogen in the different positions of the ring system was also investigated. 6-Phenyl-4H-pyrido[1,2-a]pyrimidin-4-one could be prepared by thermal cyclization of isopropylidene (6-phenylpyrid-2-ylamino)methylenemalonate, together with a small amount of 7-phenyl-1,4-dihydro-1,8-naphthyridin-4-one. © 2011 The Royal Society of Chemistry. Source


Molnar A.,Chinoin Ltd | Molnar A.,Budapest University of Technology and Economics | Boros S.,Chinoin Ltd | Simon K.,Chinoin Ltd | And 3 more authors.
Arkivoc | Year: 2010

Treatment of N,N'-di(quinoxalin-2-yl)diazene N-oxide 3 with strong acids did not give the expected Wallach-type hydroxylated product, but the first representative of the pentacyclic imidazo[1,2-a:4,5-b']diquinoxaline system 5. Heating in a weaker acid or neat furnished 1-(quinoxalin-2-yl)quinoxalin-2(1H)- one 12. The structures of these products were confirmed by independent synthesis and NMR experiments or X-ray crystallography. © ARKAT USA, Inc. Source

Discover hidden collaborations