Radical cyclization of sugar-derived beta-(alkynyloxy)acrylates: synthesis of novel fused ethers

[formula: see text] Tributyltin radical mediated cyclization of carbohydrate-derived beta-(alkynyloxy)acrylates leading to highly functionalized cis- and trans-fused bicyclic ethers of various ring sizes is described. The efficacy of the radical cyclization is nicely illustrated in the iterative construction of a trans-fused tricyclic tetrahydropyran.     

Halochrome Molekeln. Synthese und acidobasisches Verhalten substituierter 3′,6′-Bis (dimethylamino)-spiro [5H-imidazo [2, 1-α]-isoindolin-5,9′-xanthene]

Halochromic Molecules. Synthesis and Acidobasic Behaviour of Substituted 3′,6′-Bis(dimethylamino)-spiro [5H-imidazo [2,1-α]isoindolin-5,9′-xanthenes] Substituted 3′,6′-Bis (dimethylamino)-spiro [5H-imidazo [2, 1-α]isoindolin-5,9′-xanthenes] are prepared and their ¹H-NMR. spectra are discussed. An investigation of the complex protonation equilibria is made by stopped flow kinetic and spectrophotometric methods. pK values are determined and the results are discussed.     

Über die katalytische Spaltung von Orthoestern an Aluminiumoxyd

Ohne Zusammenfassung     

Über das Tabakaroma

Ohne Zusammenfassung     

Futtermittel

Ohne Zusammenfassung     

Unconditional uniqueness in the charge class for the Dirac–Klein–Gordon equations in two space dimensions

Recently, Grünrock and Pecher proved global well-posedness of the 2d Dirac–Klein–Gordon equations given initial data for the spinor and scalar fields in H ^s and H ^s+1/2 × H ^s-1/2, respectively, where s ≥ 0, but uniqueness was only known in a contraction space of Bourgain type, strictly smaller than the natural solution space C([0,T]; H ^s × H ^s+1/2 × H ^s-1/2). Here we prove uniqueness in the latter space for s ≥ 0. This improves a recent result of Pecher, where the range s > 1/30 was covered.