- Imprinted Apportionment of Functional Groups in Multivariate Metal-Organic Frameworks
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Sophisticated chemical processes widely observed in biological cells require precise apportionment regulation of building units, which inspires researchers to develop tailorable architectures with controllable heterogeneity for replication, recognition and information storage. However, it remains a substantial challenge to endow multivariate materials with internal sequences and controllable apportionments. Herein, we introduce a novel strategy to manipulate the apportionment of functional groups in multivariate metal-organic frameworks (MTV-MOFs) by preincorporating interlocked linkers into framework materials. As a proof of concept, the imprinted apportionment of functional groups within ZIF-8 was achieved by exchanging imine-based linker templates with original linkers initially. The removal of linker fragments by hydrolysis can be achieved via postsynthetic labilization, leading to the formation of architectures with controlled heterogeneity. The distributions of functional groups in the resulting imprinted MOFs can be tuned by judicious control of the interlocked chain length, which was further analyzed by computational methods. This work provides synthetic tools for precise control of pore environment and functionality sequences inside multicomponent materials.
- Feng, Liang,Wang, Kun-Yu,Lv, Xiu-Liang,Powell, Joshua A.,Yan, Tian-Hao,Willman, Jeremy,Zhou, Hong-Cai
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- Bu3SnH mediated oxidative radical cyclisation onto imidazoles and pyrroles
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A new protocol using radical cyclisation has been developed for the synthesis of [1,2-c]-fused imidazoles and [1,2-a]-fused pyrroles. The intermediate nucleophilic N-alkyl radicals, generated using Bu3SnH from N- (ω-bromoalkyl) or N-[ω-(phenylselanyl)alkyl] imidazoles and pyrroles, undergo regio-selective radical cyclisalion onto the azole rings followed by oxidative re-aromatisation.
- Aldabbagh, Fawaz,Russell Bowman,Mann, Emma,Slawin, Alexandra M.Z.
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- Turn-on trivalent cation selective chemodosimetric probe to image native cellular iron pools
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A new turn-on cell permeable chemodosimetric probe 1 has been developed and its application in the selective detection of trivalent cations (Fe 3+/Cr3+/Al3+) at a sub-nanomolar level has been demonstrated. The selectivity of 1 over a broad spectrum of mono- and divalent metal ions was established using fluorescence spectroscopy. Moreover, the changes in the absorption spectra of 1 in the presence of trivalent cations enabled the most bio-relevant metal ion Fe3+ over Cr 3+/Al3+ to be distinguished. The probe was found to be successful in the fluorescence imaging of native cellular iron pools. The fluorescence imaging of the native iron pools of banana pith further supported the high sensitivity of 1 towards Fe3+ present in living systems. To the best of our knowledge, this is the first example of a turn-on chemodosimetric probe to image native cellular Fe3+ pools. This journal is the Partner Organisations 2014.
- Venkateswarulu,Mukherjee, Trinetra,Mukherjee, Subhrakanti,Koner, Rik Rani
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- Halogen–metal exchange on bromoheterocyclics with substituents containing an acidic proton via formation of a magnesium intermediate
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A selective and practical bromine–metal exchange on bromoheterocyclics bearing substituents with an acidic proton under non-cryogenic conditions was developed by a simple modification of an existing protocol. Our protocol of using a combination of i-PrMgCl and n-BuLi has not only solved the problem of intermolecular quenching that often occurred when using alkyl lithium alone as the reagent for halogen–lithium exchange, but also offered a highly selective method for performing bromo–metal exchange on dibrominated arene compounds through chelation effect.
- Tian, Qingqiang,Shang, Suqin,Wang, Huajun,Shi, Guoqiang,Li, Zhiyao,Yuan, Jianyong
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supporting information
(2017/12/05)
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- Asymmetric Copper(II)-catalysed nitroaldol (Henry) reactions utilizing a chiral C1-symmetric dinitrogen ligand
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A series of stable chiral C1-symmetric dinitrogen ligands were conveniently synthesized in high yields by condensation of chiral amines [(-)-exo-bornylamine or (+)-(1S,2S,5R)-menthylamine] with various substituted imidazolecarbaldehydes. With the assistance of base, the ligand L1 in combination with CuCl2·2H2O (2.5 mol-% or 5.0 mol-%) can efficiently promote nitroaldol (Henry) reactions between a variety of aldehydes and nitromethane. Both aromatic and aliphatic aldehydes were tolerated in our catalytic system, affording the expected nitroalcohol products in high yields (up to 97%) and with good enantioselectivities (up to 96%) under mild reaction conditions. A series of chiral C1-symmetric dinitrogen ligands were conveniently synthesized in high yields by condensations of chiralamines with various substituted imidazolecarbaldehydes. The ligand L1 in conjunction with CuCl2·2H2O can efficiently promote nitroaldol (Henry) reactions between various aldehydes and nitromethane in high yields (up to 97%) and with good enantioselectivities (up to 96%).
- Zhou, Yirong,Gong, Yuefa
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experimental part
p. 6092 - 6099
(2011/11/29)
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- Photoinduced electron-transfer-promoted redox fragmentation of N-alkoxyphthalimides
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A new photoinduced electron-transfer-promoted redox fragmentation of N-alkoxyphthalimides has been developed. Mechanistic experiments have established that this reaction proceeds through a unique concerted intramolecular fragmentation process. This distinctive mechanism imparts many synthetic advantages, which are highlighted in the redox fragmentation of various heterocyclic substrates.
- Zlotorzynska, Maria,Sammis, Glenn M.
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supporting information; experimental part
p. 6264 - 6267
(2012/01/15)
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- NMR characterization of hydrate and aldehyde forms of imidazole-2- carboxaldehyde and derivatives
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The existence and stability of the aldehyde-hydrate form of imidazole-2-carboxaldehyde (4) were studied using FTIR together with solution- and solid-state NMR experiments. The results allowed us to conclude that the hydrate form was stable and precipitate
- Lazaro Martinez, Juan Manuel,Romasanta, Pablo Nicolas,Chattah, Ana Karina,Buldain, Graciela Yolanda
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supporting information; experimental part
p. 3208 - 3213
(2010/08/19)
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- Isoquinoline compound melanocortin receptor ligands and methods of using same
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The invention relates to melanocortin receptor ligands and methods of using the ligands to alter or regulate the activity of a melanocortin receptor. The invention further relates to tetrahydroisoquinoline aromatic amines that function as melanocortin receptor ligands and as agents for controlling cytokine-regulated physiologic processes and pathologies, and combinatorial libraries thereof.
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- Synthesis of 1-(Dimethylsulfamoyl)-2- and 5-Imidazolecarboxaldehydes. Rearrangement of 1-(Dimethylsulfamoyl)-5-imidazolecarboxaldehyde to the 4-Carboxaldehyde
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Lithiation of 1-(dimethylsulfamoyl)imidazole by n-butyllithium, followed by substitution with dimethylformamide provided 1-(dimethylsulfamoyl)-2-imidazolecarboxaldehyde in 19percent yield.When 1-(dimethylsulfamoyl)-2-(tert-butyldimethylsilyl)imidazole was lithiated by sec-butyllithium, followed by methyl formate, there was obtained 1-(dimethylsulfamoyl)-2-(tert-butyldimethylsilyl)-5-imidazolecarboxaldehyde (57percent).Removal of the silyl group by acetic acid yielded 1-(dimethylsulfamoyl)-5-imidazolecarboxaldehyde (11, 96percent) as a gum.Isomerization of 11 took place slowly at room temperature (10 days), or faster in tetrahydrofuran solution containing triethylamine (2 hours) to form crystalline 1-(dimethylsulfamoyl)-4-imidazolecarboxaldehyde (12) in 68percent yield.Proton and carbon-13 nmr spectra were alanyzed to determine the structure of the isomers.However, only X-ray crystallography established the structure of 1-(dimethylsulfamoyl)-4-imidazolecarboxaldehyde, unequivocally.A mechanism for the isomerization of 11 to 12 is proposed.
- Kim, Jang-Woo,Abdelaal, Salma M.,Bauer, Ludwig,Heimer, Norman E.
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p. 611 - 620
(2007/10/02)
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- Angiotensin-II receptor blocking, heterocycle substituted imidazoles
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Novel heterocycle substituted imidazoles of Formula (I), which are useful as angiotensin-II antagonists, are disclosed: STR1
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- 2,2'-bi-1H-imidazoles
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This invention relates to novel derivatives of 2,2'-bi-1H-imidazoles, to the processes and intermediates used in their preparation, to their ability to exert the pharmacologic effects of lowering high blood pressure and of increasing heart contractile force and to their use as chemotherpauetic agents useful in treating cardiac insufficiency and hypertension.
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- Synthesis, molecular structure, and complexation of 1,4-dihydropyridines containing ligands for intramolecular complexation of metal electrophiles
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A series of 4-substituted Hantzsch 1,4-dihydropyridines has been synthesized.Substituents at the 4-position include 2-pyridyl, 2-imidazolyl, and 1-methyl-2-imidazolyl.By use of various acetoacetic ester derivatives methoxy and methylthio groups have been introduced in the ester side chains at the 3,5-positions.A representative example is bis(2-methoxyethyl) 1,4-dihydro-2,6-dimethyl-4-(1H-imidazol-2-yl)-3,5-pyridinedicarboxylate (5h).The crystal structure of bis1,4-dihydro-2,6-dimethyl-4-(1H-imidazol-2-yl)-3,5-pyridinedicarboxylate (5i) has been determined.The imidazole group at the 4-position is located in a pseudo-axial position.In the 13C- and 1H-NMR spectra line doubling is seen in the 4-imidazole-substituted derivatives.This is apparently the result of slow tautomerization.Various complexes with Zn(NO3)2*4H2O have been prepared but no crystal structures could be obtained.These 1,4-dihydropyridines have little capacity, either in the presence or absence of metal ions, to carry out reductions.This may be the result of a stereoelectronic effect caused by the (presumably) equatorial orientation of the hydrogen (hydride) to be donated.
- Kaptein, Bernard,Kellogg, Richard M.,Bolhuis, F. van
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p. 388 - 395
(2007/10/02)
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