- Copper-Catalyzed Annulation of Oxime Acetates with α-Amino Acid Ester Derivatives: Synthesis of 3-Sulfonamido/Imino 4-Pyrrolin-2-ones
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A copper-catalyzed annulation of oxime acetates and α-amino acid ester derivatives for the easy preparation of 4-pyrrolin-2-ones bearing a 3-amino group has been developed. This process features the oxidation of amines with oxime esters as the internal oxidant to produce the active 1,3-dinucleophilic and 1,2-dielectrophilic species concurrently. The subsequent nucleophilic cyclization realizes the efficient construction of 4-pyrrolin-2-one derivatives.
- Miao, Chun-Bao,Zheng, An-Qi,Zhou, Li-Jin,Lyu, Xinyu,Yang, Hai-Tao
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supporting information
p. 3381 - 3385
(2020/04/21)
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- Hydrophilic scaffolds of oxime as the potent catalytic inactivator of reactive organophosphate
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Despite its efficacy as a skin decontaminant of reactive organophosphates (OP), Dekon 139—a potassium salt of 2,3-butanedione monooxime (DAM)—is associated with adverse events related to percutaneous absorption largely due to its small size and lipophilicity. In order to address this physicochemical issue, we synthesized and evaluated the activity of a focused library of 14 hydrophilic oxime compounds, each designed with either a DAM or monoisonitrosoacetone (MINA) oxime tethered to a polar or charged scaffold in order to optimize the size, hydrophilicity, and oxime acidity. High-throughput colorimetric assays were performed with paraoxon (POX) as a model OP to determine the kinetics of POX inactivation by these compounds under various pH and temperature conditions. This primary screening led to the identification of 6 lead compounds, predominantly in the MINA series, which displayed superb catalytic activity by reducing the POX half-life (t1/2) by 2–3 fold relative to Dekon 139. Our mechanistic studies show that POX inactivation by the oxime compounds occurred faster at a higher temperature and in a pH-dependent manner in which the negatively charged oximate species is ≥ 10–fold more effective than the neutral oxime species. Lastly, using one of the lead compounds, we demonstrated its promising efficacy for POX decontamination in porcine skin ex vivo, and showed its potent ability to protect acetylcholine esterase (AChE) through POX inactivation. In summary, we report the rational design and chemical biological validation of novel hydrophilic oximes which address an unmet need in therapeutic OP decontamination.
- Tang, Shengzhuang,Wong, Pamela T.,Cannon, Jayme,Yang, Kelly,Bowden, Sierra,Bhattacharjee, Somnath,O'Konek, Jessica J.,Choi, Seok Ki
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- Structures, luminescent and magnetic properties of three dinuclear lanthanide complexes: Magnetic refrigeration and single-molecule magnet behaviour
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Three dinuclear lanthanide complexes: {[Ln2(L)2(pbd)4]·2CH3CN} (Ln = Eu (1), Gd (2), Dy (3); HL = 2-(hydroxyimino)-N′-(pyridin-2-ylmethylene)propanehydrazonic acid, pbd = 1-phenylbutane-1,3-dione) were fabricate
- Li, Peng-Fei,Shi, Tian-Xing,Chen, Ying-Ying,Shao, Li-Jun,Yu, Hong,Fang, Ming,Wang, Wen-Min,Wu, Zhi-Lei
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p. 371 - 376
(2018/12/02)
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- Modulating the magnetization dynamics of rare earth complexes by structural regulation utilizing different solvents
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Five novel di- and tetra-nuclear rare earth complexes were synthesized by the variation of the solvent molecules: [Nd2(dbm)2(L)2(CH3OH)2]·0.75CH3OH (1), [Dy2(dbm)2(L)
- Wu, Dong-Fang,Shen, Hai-Yun,Chang, Wen-Ju,Zhao, Li-Hua,Cui, Jian-Zhong,Gao, Hong-Ling
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supporting information
p. 43 - 53
(2018/12/13)
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- Exploring Tuning of Structural and Magnetic Properties by Modification of Ancillary β-Diketonate Co-ligands in a Family of Near-Linear Tetranuclear DyIII Complexes
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Three tetranuclear DyIII complexes, [Dy4(LH)2(CH3OH)4(acac)6] (1), [Dy4(LH)2(CH3OH)4(hmacac)6]·2CH3OH (2), and [Dy4(LH)2(CH3OH)4(dpacac)6]·2CHCl3·2CH3OH·2H2O (3), have been synthesized and characterized [LH4 = (2E,N′E)-N′-(2,3-dihydroxybenzylidene)-2-(hydroxyimino)propanehydrazide; acacH = acetylacetone; hmacacH = 2,2,6,6-tetramethyl-3,5-heptanedione; dpacacH = dibenzoylmethane]. The structural elucidation of these complexes reveals two types of DyIII centers in terms of the number of ancillary β-diketonate co-ligands coordinated to the metal centers. Detailed magnetic studies have been carried out on 1-3 which reveal a slow relaxation of magnetization at low temperatures. The relaxation of complexes 2 and 3 is distributed in three temperature ranges: lower temperature process, transition range, and higher temperature process. In the higher temperature range, the best fitting of the data for 2 yields τ0 = (6.3 ± 3.6) × 10-6 s and Ueff = (23.8 ± 4.0) K, and for 3, τ0 = (9.4 ± 5.9) × 10-6 s, Ueff = (29.0 ± 6.3) K.
- Acharya, Joydev,Biswas, Sourav,Van Leusen, Jan,Kumar, Pawan,Kumar, Vierandra,Narayanan, Ramakirushnan Suriya,K?gerler, Paul,Chandrasekhar, Vadapalli
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p. 4004 - 4016
(2018/06/11)
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- Regulating the luminescent and magnetic properties of rare-earth complexes with β-diketonate coligands
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Eleven dinuclear rare-earth (RE) complexes, [RE2(dbm)2L2(DMF)2]·2CH3OH (RE = Y (1), Nd (2), Dy (6), Er (7)), [RE2(dbm)2L2(CH3OH)2]·nCH3OH (RE = Eu (3), Gd (4), Tb (5), Yb (8)) and [RE2(acac)2L2(CH3OH)2] (RE = Dy (9), Er (10), Yb (11)) (H2L = N′-(2-hydroxybenzylidene)-2-(hydroxyimino)-propanohydrazide, dbm- = 1,3-diphenyl-1,3-propanedionate, acac- = acetylacetonate, DMF = N,N-dimethylformamide) have been synthesized, and structurally and magnetically characterized. The rare-earth ions of the eleven complexes are all located in an eight-coordinated environment. The luminescence spectra in methanol solution show that complexes 3, 5 and 6 exhibit the typical emissions of the RE(iii) ions, while complex 1 exhibits an emission peak similar to that of the H2L ligand. And for complexes 2, 7, 8 and 11, all of them show near-infrared fluorescent characteristic peaks. Magnetic studies reveal that complex 4 can act as a cryogenic magnetic refrigerant with the maximum magnetic entropy change (-ΔSm) of 25.79 J kg-1 K-1 at 7 T and 2 K. Complex 9 shows slow magnetic relaxation behavior with an energy barrier of 23.78 K and the pre-exponential factor of 1.74 × 10-6 s, while complex 6 does not exhibit excellent SMM behavior. Besides, complex 9 presents multiple relaxation processes when subjected to an additional dc magnetic field of 2000 Oe. The distinct magnetic relaxation behaviors of the two Dy2 complexes originate from the different coordination environment around the Dy(iii) ions. These results mean that the luminescence and magnetic properties of rare-earth complexes can be finely tuned by altering the β-diketonate ligands.
- Chu, Xiao-Ya,Wang, Wen-Min,Nie, Yao-Yao,Cui, Jian-Zhong,Gao, Hong-Ling
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supporting information
p. 11417 - 11429
(2018/07/24)
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- Modulation of the relaxation dynamics of linear-shaped tetranuclear rare-earth clusters through utilizing different solvents
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Nine new tetranuclear centrosymmetric linear complexes, [RE4(dbm)8L2(DMF)2]·nCH2Cl2·mC2H3N (RE = Y (1), Tb (2), Dy (3), Ho (4), Er (5), Lu (6)) and [RE4(dbm)8L2(C2H5OH)2]·nCH3CN (RE = Tb (7), Dy (8), Ho (9)) (HL = 2-[(2-(hydroxyimino)propanehydrazide)methyl]-8-hydroxyquinoline and dbm = 1,3-diphenyl-1,3-propanedione) have been synthesized. Complexes 1-9 are tetranuclear complexes. Magnetic studies reveal that both DyIII-based complexes (3 and 8) exhibit single-molecule magnet (SMM) behavior under a zero dc field. Furthermore, complex 3 presents one relaxation process under a zero dc field, while application of an external dc field (1500 Oe) induces multi-relaxation signals of the ac magnetic susceptibility.
- Zhang, Ru-Xia,Chang, Yi-Xin,Shen, Hai-Yun,Wang, Wen-Min,Zhou, Xiao-Pu,Wang, Ni-Ni,Cui, Jian-Zhong,Gao, Hong-Ling
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supporting information
p. 19117 - 19126
(2016/12/09)
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- Concise Total Synthesis of Trichodermamides A, B, and C Enabled by an Efficient Construction of the 1,2-Oxazadecaline Core
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We report herein a facile and efficient method of the construction of the cis-1,2-oxazadecaline system, distinctive of (pre)trichodermamides, aspergillazine A, gliovirin, and FA-2097. The formation of the 1,2-oxazadecaline core was accomplished by a 1,2-addition of an αC-lithiated O-silyl ethyl pyruvate oxime to benzoquinone, which is followed by an oxa-Michael ring-closure. The method was successfully applied to the concise total synthesis of trichodermamide A (in gram quantities) and trichodermamide B, as well as the first synthesis of trichodermamide C.
- Mfuh, Adelphe M.,Zhang, Yu,Stephens, David E.,Vo, Anh X. T.,Arman, Hadi D.,Larionov, Oleg V.
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supporting information
p. 8050 - 8053
(2015/07/15)
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- TETRAZOLYL OXIME DERIVATIVE, SALT THEREOF, AND PLANT DISEASE
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The present invention provide a tetrazolyl oxime derivative represented by formula (1) (in formula (1), X represents a halogen atom or the like, n1 represents an integer of 0 to 5, A represents a tetrazolyl group, Het represents a group represented by for
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Page/Page column 10
(2012/01/13)
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- Metal nitrite: A powerful oxidizing reagent
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An efficient and simple source of nitroso reagents and their oxidation reactions are described. The combination of a Lewis acid and a metal nitrite was applied to the oxidation of silyl enol ethers. Amino acid and peptide derivatives were easily accessed through in situ C-C bond cleavage of fully substituted silyl enol ethers upon oxidation.
- Baidya, Mahiuddin,Yamamoto, Hisashi
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p. 13880 - 13882
(2011/10/09)
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- NOVEL PRODRUGS
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The present invention describes novel prodrugs of formula (I) or their salts, process of preparation and uses thereof.
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Page/Page column 36-37
(2008/12/07)
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- In vitro and in vivo stability investigations of Cu(II), Zn(II), Ca(II) and Gd(III) complexes with N,N′-bis(2-hydroxyiminopropionyl) propane-1,3-diamine
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Formation constants of copper(II), zinc(II), calcium(II) and gadolinium(III) with N,N′-bis(2-hydroxyiminopropionyl) propane-1,3-diamine (L2) have been studied at 25°C and an ionic strength of 0.15 mol dm-3. The reasonably high formation constants of the copper with this ligand are due to the ease with which the metal ion deprotonates the amide moieties. The square-planar coordination of L2 towards copper as predicted from UV-visible data may also account for the high selectivity of L2 towards the metal ion. Octanol/water partition coefficients of Cu(II)-L2 complexes indicate that although these complexes are largely hydrophilic, approximately 1.86% of the [CuL2H-1] species goes into the octanol layer and hence may promote dermal absorption of copper with a calculated penetration rate of 1.24 × 10-5 cm h-1. The [CuL2H-1] complex which predominates at pH 7.4 is a poor mimic of native copper-zinc Superoxide dismutase. Blood-plasma simulation studies predict that, despite the high concentration of zinc and calcium in vivo, L2 is able to increase the low-molecular-mass fraction of copper. Biodistribution experiments using 64Cu-labelled [CuL2H-1] indicate an initial high uptake of this species in the liver, but it is predominantly excreted through the renal system.
- Nomkoko, Edmund T.,Jackson, Graham E.,Nakani, Bandile S.
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p. 1432 - 1440
(2007/10/03)
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- New Synthesis of α-Nitroso Esters and Oximes of α-Keto Esters
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Ketene O-alkyl O'-silyl acetals on reaction with nitric oxide or isoamyl nitrite in the presence of titanium(IV) chloride provide either one of α-nitroso esters and oximes of α-keto esters.
- Ali, Syed Masarrat,Matsuda, Yoshihiko,Tanimoto, Shigeo
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p. 805 - 806
(2007/10/02)
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- Nitrosoalkenes: Synthesis and Reactivity
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Some α- and β-halonitrosoalkenes 1 have been synthesized and characterized.The halogen atoms of the oxime precursors 2 can be substituted by alkoxy groups.Two kinds of cycloaddition reaction of 1 have been observed: i) reaction of the NO group with dienes
- Francotte, Eric,Merenyi, Robert,Vandenbulcke-Coyette, Brigitte,Viehe, Heinz-Guenther
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p. 1208 - 1218
(2007/10/02)
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