نتایج جستجو برای: nn alkylidene bisamide
تعداد نتایج: 11752 فیلتر نتایج به سال:
Four new compounds, the limonoid 24-epi-melianodiol (8), the tirucallane aglaiodiol (9), and the two cyclopentatetrahydrobenzopyran derivatives pyramidaglain A (11) and B (12) were isolated from the leaves of Aglaia andamanica Hiern (Meliaceae), together with the eleven known constituents beta-sitosterol, beta-sitosterol glucoside, cycloart-23E-ene-3 beta,25-diol (1), three flavonoids 5-hydroxy...
Terbium(III) was coordinated to four novel 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) amphiphilic bisamide ligands. The complexes were assembled into mono-disperse micellar nano-aggregates and for the first time Tb(III) has been evaluated as a single lanthanide negative bimodal contrast agent for MRI/OI. The complexes show characteristic Tb(III) emission with quantum yields...
Addition of 1 equiv of [HNMe2Ph]BAr4 (Ar ) 3,5-(CF3)2C6H3) to Mo(NAr)(CHCMe2Ph)(Pyrrolide)2 (Pyrrolide ) parent pyrrolide (Pyr) or 2,5-dimethylpyrrolide (Me2Pyr)) species in THF produced [Mo(NAr)(CHCMe2Ph)(Pyrrolide)(THF)x]BAr4 species (x ) 2 for Me2Pyr (1b) or 3 (1a) for Pyr; Ar ) 2,6-diisopropylphenyl). [Mo(NAr)(CHCMe2Ph)(Me2Pyr)(2,4-lutidine)]BAr4 (1c) was formed upon addition of 2,4-lutidin...
Several regioselectively π-extended, pyrrole fused porphyrinoids have been synthesized by the 1,3-dipolar cycloaddition of meso-alkylidene-(benzi)porphyrins. Pd(II) complexes gave oxidation resistant, bis-pyrrole fused adducts. The repeated 1,3-dipolar cycloaddition followed by oxidation-reduction of pentaphyrin analogs afforded π-extended porphyrin analogs.
Lewis acid-mediated conjugate addition of vinyl azides to electron-deficient alkenes led to the efficient construction of 1-pyrroline skeletons. The reactions of vinyl azides with 3-alkylidene-2-oxoindolines afford 3',4'-dihydrospiro[indoline-3,2'-pyrrol]-2-ones in a diastereoselective fashion, whereas those with dimethyl 2-alkylidenemalonates provide 4,5-dihydro-3H-pyrroles.
Acyclic diamines are valuable feedstocks for polyamide synthesis. Ruthenium-alkylidene catalysed cross metathesis of amino alkenes is problematic and acyl derivatisation can result in less efficient syntheses, poor catalyst turnover and isomerisation. Temporary amine masking via stable and soluble ammonium salts delivers cyclic and acyclic aminoalkenes in high yield and purity.
In the 70’s, there has been many indications of new mesons coupled to the nucleon–antinucleon (NN) system. States below the NN threshold were claimed, e.g., in radiative transitions NN → X + γ. Above the threshold, states were tentatively seen as bumps in cross sections. Clarifying the experimental situation was one of the main motivation for building the lowenergy part of the antiproton beam f...
Molecular characterization of the Hansenula polymorpha FLDI gene encoding formaldehyde dehydrogenase
Richard J. S. Baerends,{, Grietje J. Sulter, Thomas W. Jeffries, James M. Cregg and Marten Veenhuis* 1 Eukaryotic Microbiology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Kerklaan 30, 9751 NN Haren, The Netherlands 2 Institute for Microbial and Biochemical Technology, Forest Products Laboratory, US Department of Agriculture, One Gifford Pinchot Drive, ...
Cu(I)-catalyzed asymmetric Michael addition of cyclic ketimino esters with alkylidene malonates has been developed for efficient construction of β-branched α-amino acids containing adjacent quaternary and tertiary stereogenic centers in good yields with excellent diastereo-/enantioselectivities. The generated Michael adduct was further converted to the biologically important pyrrolizidine analo...
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