- Michael versus retro-Michael reaction in the regioselective synthesis of N-1 and N-3 uracil adducts
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By controlling the temperature or reaction time in the base-catalysed Michael-type addition of 5-substituted uracil derivatives we were able to synthesise N-1 or N-3 uracil adducts using methyl acrylate and acrylonitrile as acceptors. The mechanism of this chemical inequivalence was established using 1H NMR spectroscopic studies. The investigations revealed that formation of the N-1 adduct was achievable under kinetically controlled conditions irrespective to the type of the base used (TEA, DBU). In turn, synthesis of the N-3 adducts proceeded from the initially formed N-1,N-3 diadduct via a retro-Michael reaction which dominates at elevated temperature or prolonged reaction time.
- Boncel, S?awomir,McZka, MacIej,Walczak, Krzysztof Z.
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experimental part
p. 8450 - 8457
(2010/12/25)
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- Symmetrical and unsymmetrical α,ω-nucleobase amide-conjugated systems
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We present the synthesis and selected physicochemical properties of several novel symmetrical and unsymmetrical α,ω-nucleobase mono-and bis-amide conjugated systems containing aliphatic, aromatic or saccharidic linkages. The final stage of the synthesis i
- Boncel, Slawomir,Mazka, MacIej,Motyka, Radoslaw,Walczak, Krzysztof Z.,Koziol, Krzysztof K. K.
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scheme or table
(2010/07/09)
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- Novel acyclic amide-conjugated nucleosides and their analogues
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An effective one-step synthesis of new amide-conjugated nucleosides and their analogues, in the presence of 4-(4,6-dimethoxy-1,3,5-triazin-2-yl)-4- methylmorpholinium chloride (DMT-MM) as the condensing agent, is presented. Substrate subunits carrying carboxylic group were obtained by acidic hydrolysis of Michael-type adducts of various 5-substituted uracil derivatives to methyl acrylate. Amine substrate was synthesized by reduction of 1-(2′- cyanoethyl)thymine with sodium borohydride in the presence of nickel (II) chloride as catalyst. Other applied amine substrates were 5′-amino- 5′-deoxythymidine and 5-aminouracil. Copyright Taylor & Francis Group, LLC.
- Boncel, Slawomir,Walczak, Krzysztof
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experimental part
p. 103 - 117
(2009/06/18)
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