N-(2-(Pyridin-2-yl)ethyl)benzenesulfonamide derivatives and 1,1,1-trifluoro-N-(2-(pyridin-2-yl)ethyl)methanesulfonamide (1-4), along cat. with three-legged piano stool Cp*(IrCl)-Cl-III complexes (5-11) (Cp* = pentamethylcyclopentadienyl) bearing pyridinesulfonamide ligands with varying electronic parameters, were synthesized. These ligands and air-stable complexes were characterized by H-1 and C-13{H-1} NMR spectroscopy, elemental analysis, and single-crystal X-ray diffraction. Precatalysts, 5-11, were assessed for transfer hydrogenation of aryl, diaryl, dialkyl, linear, cycloaliphatic, and alpha,beta-unsaturated ketones, diones, beta-ketoesters, and a biomass-derived substrate with 2-propanol, using 1 mol % precatalyst. Catalysis was also efficient using a 0.1 mol % loading. Remarkably, all catalysis experiments can be conducted in air without dried and degassed substrates, and basic additives and halide abstractors are not required for high activity in transfer hydrogenation. Control experiments and a mercury poisoning experiment support a homogeneous catalyzed pathway. Overall, the fastest reactions are observed using electron-poor substrates and precatalysts bearing electron-rich ligands.
Ligand-Free Copper(I)-Catalyzed Benzylic Acyloxylation of 2-Alkylpyridines under Aerobic Conditions
作者:Li Cheng、Yuqian Sun、Wenrong Wang、Changsheng Yao、Tuan-Jie Li
DOI:10.1021/acs.joc.8b02794
日期:2019.3.15
A ligand-free copper(I)-catalyzed benzylic acyloxylation of 2-alkylpyridines with carboxylic acids was realized by using 1.0 atm of O2 as a green oxidant. The transformation provided a facile access to a wide range of N-heterocyclic esters through C–O bond formation, with broad substrate scope and good functional group tolerance. Preliminary mechanistic investigations showed that this protocol included
Electrochemical C−H Amidation of Heteroarenes with<i>N</i>‐Alkyl Sulfonamides in Aqueous Medium
作者:Yan Zhang、Zhipeng Lin、Lutz Ackermann
DOI:10.1002/chem.202004229
日期:2021.1.4
The construction of C−N bonds by free radical reactions represents a powerful synthetic approach for direct C−Hamidations of arenes or heteroarenes. Developing efficient and more environmentally friendly synthetic methods for C−Hamidationreactions remains highly desirable. Herein, metal‐free electrochemical oxidative dehydrogenative C−Hamidations of heteroarenes with N‐alkylsulfonamides have been
作者:Kelly J. Kilpin、William Henderson、Brian K. Nicholson
DOI:10.1039/b803835j
日期:——
The pyridyl-2-alkylsulfonamides C5H4N(CH2)nNHSO2R (n = 1,2; R = Me, Ph or p-C6H4Me) and 8-(p-tosylamino)quinoline undergo facile cycloauration reactions with H[AuCl4] in water, giving metallacyclic complexes coordinated through the pyridyl (or quinolyl) nitrogen atom and the deprotonated nitrogen of the sulfonamide group. The complexes have been fully characterised by NMR spectroscopy, ESI mass spectrometry and elemental analysis. The X-ray crystal structures of two derivatives reveal the presence of non-planar sulfonamide nitrogen atoms. The complexes show low activity against P388 murine leukaemia cells, possibly as a result of their ease of reduction with mild reducing agents.
Compounds of the present invention, and pharmaceutically acceptable compositions thereof, are useful as modulators of ATP-Binding Cassette (“ABC”) transporters or fragments thereof, including Cystic Fibrosis Transmembrane Conductance Regulator (“CFTR”). The present invention also relates to methods of treating ABC transporter mediated diseases using compounds of the present invention.
Synthesis and Some First-Row Transition-Metal Complexes of the 1,2,4-Triazole-Based Bis(terdentate) Ligands TsPMAT and PMAT
作者:Marco H. Klingele、Boujemaa Moubaraki、Keith S. Murray、Sally Brooker
DOI:10.1002/chem.200500387
日期:2005.11.18
octahedral, as evidenced by the X-ray crystalstructure analyses of [Co(II) (2)(TsPMAT)(2)](BF(4))(4)6 MeCN (246 MeCN) and [Fe(II) 2(PMAT)2](BF4)4DMF (27DMF). Studies of the magnetic properties of [Co(II) 2(TsPMAT)2](BF4)4.4 H2O (244 H2O), [Mn(II) 2(PMAT)2](ClO4)4 (26), and [Co(II) 2(PMAT)2](BF4)4 (28) have revealed weak antiferromagnetic coupling (J=-3.3, -0.16, and -2.4 cm(-1), respectively) between the two