286-45-3Relevant articles and documents
Highly efficient aerobic epoxidation of cyclic olefins in mild conditions by a novel binuclear manganese(II) complex containing N-(4-nitrophenyl)picolinamide ligand
Bagherzadeh, Mojtaba,Ghanbarpour, Alireza,Khavasi, Hamid Reza
, p. 72 - 75 (2015)
A novel binuclear Mn(II) complex based on a para-nitro substituted amidic ligand (N-(4-nitrophenyl)picolinamide) has been synthesized and characterized by X-ray crystallography. This complex shows a high degree of conversion and epoxide selectivity in Mukaiyama aerobic epoxidation reactions of cyclic olefins in mild conditions.
Multilayer structured MFI-type titanosilicate: Synthesis and catalytic properties in selective epoxidation of bulky molecules
Wang, Jianggan,Xu, Le,Zhang, Kun,Peng, Honggen,Wu, Haihong,Jiang, Jin-Gang,Liu, Yueming,Wu, Peng
, p. 16 - 23 (2012)
A lamellar titanosilicate (LTS-1) was hydrothermally synthesized by employing a bifunctional surfactant as the structure-directing agent (SDA). Highly crystalline LTS-1 was obtained at an optimal SDA/Si molar ratio of 0.04. As-synthesized LTS-1 possessed a multilayer structure, which was constructed from a collection of 2-nm zeolite nanosheets and interlayer SDA molecules. Removing the intercalated organic species induced irregular layer stacking to a certain extent, leading to intracrystal mesopores of ca. 3.2 nm in diameter. The catalytic performance of LTS-1 was investigated in the epoxidation of various bulky alkenes with tert-butyl hydroperoxide, cumene hydroperoxide, or aqueous H2O2. LTS-1 was more active than conventional titanosilicates for reactions involving bulky alkenes and oxidants, and it was immune to Ti leaching and irreversible deactivation.
Proton Switch in the Secondary Coordination Sphere to Control Catalytic Events at the Metal Center: Biomimetic Oxo Transfer Chemistry of Nickel Amidate Complex
Kim, Soohyung,Jeong, Ha Young,Kim, Seonghan,Kim, Hongsik,Lee, Sojeong,Cho, Jaeheung,Kim, Cheal,Lee, Dongwhan
supporting information, p. 4700 - 4708 (2021/02/12)
High-valent metal-oxo species are key intermediates for the oxygen atom transfer step in the catalytic cycles of many metalloenzymes. While the redox-active metal centers of such enzymes are typically supported by anionic amino acid side chains or porphyrin rings, peptide backbones might function as strong electron-donating ligands to stabilize high oxidation states. To test the feasibility of this idea in synthetic settings, we have prepared a nickel(II) complex of new amido multidentate ligand. The mononuclear nickel complex of this N5 ligand catalyzes epoxidation reactions of a wide range of olefins by using mCPBA as a terminal oxidant. Notably, a remarkably high catalytic efficiency and selectivity were observed for terminal olefin substrates. We found that protonation of the secondary coordination sphere serves as the entry point to the catalytic cycle, in which high-valent nickel species is subsequently formed to carry out oxo-transfer reactions. A conceptually parallel process might allow metalloenzymes to control the catalytic cycle in the primary coordination sphere by using proton switch in the secondary coordination sphere.
Nonheme manganese(III) complexes for various olefin epoxidation: Synthesis, characterization and catalytic activity
Lee, Sojeong,Park, Soyoung,Lee, Myoung Mi,Lee, Jiyoung,Kim, Cheal
, (2021/03/14)
Three mononuclear imine-based non-heme manganese(III) complexes with tetradentate ligands which have two deprotonated phenolate moieties, ([(X2saloph)Mn(OAc)(H2O)], 1a for X = Cl, 1b for X = H, and 1c for X = CH3, saloph = N,N-o-phenylenebis(salicylidenaminato)), were synthesized and characterized by 1H NMR, 13C NMR, ESI-Mass and elemental analysis. MnIII complexes catalysed efficiently various olefin epoxidation reactions with meta-chloroperbenzoic acid (MCPBA) under the mild condition. MnIII complexes 1a and 1c with the electron-withdrawing group -Cl and electron-donating group –CH3 showed little substituent effect on the epoxidation reactions. Product analysis, Hammett study and competition experiments with cis- and trans-2-octene suggested that MnIV = O, MnV = O, and MnIII-OOC(O)R species might be key oxidants in the epoxidation reaction under this catalytic system. In addition, the use of PPAA as a mechanistic probe demonstrated that Mn-acylperoxo intermediate (MnIII-OOC(O)R) 2 generated from the reaction of peracid with manganese complexes underwent both the heterolysis and the homolysis to produce MnV = O (3) or MnIV = O species (4). Moreover, the MnIII-OOC(O)R 2 species could react directly with the easy-to-oxidize substrate to give epoxide, whereas the species 2 might not be competent to the difficult-to-oxidize substrate for the epoxidation reaction.
PEPTIDE CONJUGATES OF CYTOTOXINS AS THERAPEUTICS
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Paragraph 0448-0449, (2021/01/25)
The present invention relates to peptide conjugates of cytotoxins such as topoisomerase I inhibitors which are useful for the treatment of diseases such as cancer.
