A novel and general approach for (13)C(2)- and (2)H-labeled phenethylamine derivatives has been developed, based on a highly convergent single-step assembly of the carbon skeleton. The efficient incorporation of two carbon-13 isotopes into phenethylamines was accomplished using a palladium-catalyzed double carbonylation of aryl iodides with near stoichiometric carbon monoxide. 相似文献
We introduce admissible lattices and Gabor pairs to define discrete versions of wave-front sets with respect to Fourier–Lebesgue and modulation spaces. We prove that these wave-front sets agree with each other and with corresponding wave-front sets of “continuous type”. This implies that the coefficients of a Gabor frame expansion of f are parameter dependent, and describe the wave-front set of f. 相似文献
Ring‐opening metathesis polymerization (ROMP) was used for the synthesis of monolithic capillary columns with inner diameters of 200 µm. The resulting polymeric monoliths were characterized by inverse size‐exclusion chromatography (ISEC). Surface functionalization was carried out in situ using 2‐(N,N‐dimethylaminoethyl)norborn‐5‐ene‐2‐ylcarboxylic amide ( 1 ). The resulting functionalized monoliths were successfully used in anion‐exchange chromatography of oligodeoxynucleotides.
We have obtained the single-crystal X-ray crystallographic structures of the bisphosphonates [(1-isoquinolinylamino)methylene]-1,1-bisphosphonate and [[(5-chloro-2-pyridinyl)amino]methylene]-1,1-bisphosphonate, bound to the enzyme 1-deoxyxylulose-5-phosphate reductoisomerase (DXR, EC 1.1.1.267, also known as 2-C-methyl-d-erythritol-4-phosphate synthase), an important target for the development of antimalarial drugs. Our results indicate that both bisphosphonates bind into the fosmidomycin binding site. The aromatic groups are in a shallow hydrophobic pocket, and the phosphonate groups are involved in electrostatic interactions with Mg2+ or a cluster of carboxylic acid groups and lysine while the fosmidomycin phosphonate-binding site is occupied by a sulfate ion (as also observed in the DXR/NADP+ structure). The availability of these two new crystal structures opens up the possibility of the further development of bisphosphonates and related systems as DXR inhibitors and, potentially, as antiinfective agents. 相似文献
Herein, we report a nickel-catalyzed carbonylative coupling of α-bromonitriles and alkylzinc reagents with near stoichiometric carbon monoxide to give β-ketonitriles in good yields. The reaction is catalyzed by a readily available and stable nickel(II) pincer complex. The developed protocol tolerates substrates bearing a variety of functional groups, which would be problematic or incompatible with previous synthetic methods. Additionally, we demonstrate the suitability of the method for carbon isotope labeling by the synthesis of 13C-labeled β-ketonitriles and their transformation into isotopically labeled heterocycles. 相似文献