- Synthesis and cytotoxicity of novel imidazo[4,5-d]azepine compounds derived from marine natural product ceratamine A
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A series of novel imidazo[4,5-d]azepine compounds derived from marine natural product ceratamine A were designed and synthesized in 7 steps. Most compounds exhibited comparable cytotoxicity against five human cancer cell lines (HCT-116, HepG2, BGC-823, A549 and A2780) to natural product ceratamine A. Compound 1k, bearing methoxy group at C-14, C-15 and C-16, showed the best in vitro cytotoxicity, which was better than ceratamine A. The structure and activity relationships study showed that the benzyloxymethyl group on N-3 played an important role on the cytotoxicity.
- Pan, Xuan,Tao, Lulu,Ji, Ming,Chen, Xiaoguang,Liu, Zhanzhu
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- Tripodal scaffolds with three appended imidazole thiones for Cu(I) chelation and protection from Cu-mediated oxidative stress
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Imidazole thiones appear as interesting building blocks for Cu(I) chelation and protection against Cu-mediated oxidative stress. Therefore, a series of tripodal molecules derived from nitrilotriacetic acid appended with three imidazole thiones belonging either to histamine-like or histidine-like moieties were synthesized. These tripods demonstrate intermediate affinity between that previously measured for tripodal analogues bearing three thiol moieties such as cysteine and those grafted with three thioethers, like methionines, consistently with the thione group in the imidazole thione moiety existing as a tautomer between a thiol and a thione. The two non-alkylated tripods derived from thioimidazole, TH and TH* demonstrated three orders of magnitude larger affinity for Cu(I) (logKpH 7.4 = 14.3) than their analogues derived from N,N′-dialkylated thioimidazole TMe and TEt (logKpH 7.4 = 11–11.6). Their efficiency to inhibit Cu-mediated oxidative stress is demonstrated by several assays involving ascorbate consumption or biomolecule damages and correlates with their ability to chelate Cu(I), related to their conditional complexation constants at pH 7.4. The two non-alkylated tripods derived from thioimidazole, TH and TH* are significantly more powerful in reducing Cu-mediated oxidative stress than their analogues derived from N,N′-dialkylated thioimidazole TMe and TEt.
- Das, Ranajit,Claron, Michael,Lebrun, Colette,Pécaut, Jacques,Ambala, Srinivas,Gateau, Christelle,Roy, Gouriprasanna,Delangle, Pascale
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- Monocycloplatinated Solvento Complex Displays Turn-on Ratiometric Phosphorescence Responses to Histamine
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The study of biological histamine (HA) requires probes capable of ratiometric photoluminescence detection of HA. We discovered that a monocycloplatinated complex having two solvento ligands ([Pt(2-(2-naphthyl)quinolinate)(NCCH3)2]ClO4) could produce ratiometric phosphorescence responses to HA in aerated aqueous solutions buffered to pH 7.4. The HA response was characterized with a hypsochromic shift of an emission peak wavelength from 635 to 567 nm. The corresponding phosphorescence intensity ratio (i.e., I567 nm/I635 nm) increased from 0.26 to 1.90. Spectroscopic and spectrometric investigations indicated an occurrence of spontaneous displacement of the labile CH3CN ligands with HA. An independently prepared HA adduct supported this notion. The ratiometric phosphorescence responses to HA were highly tolerant to other biological stimuli, including changes in pH and the presence of biometals and biological Lewis bases such as amino acids, nucleosides, biothiols, neurotransmitters, and small molecular metabolites. Of note was the high selectivity toward HA over common biological ligands, including histidine, cysteine, and homocysteine, which was ascribed to tighter HA binding. Our phosphorescence measurements employing Boc-protected derivatives of HA suggested that the bis-chelate motif involving imidazolyl and terminal amino groups was crucial for eliciting the ratiometric phosphorescence signaling. Finally, the bioimaging utility of the HA probe was validated using RAW 264.7 macrophages that were exogenously supplemented with HA or stimulated with thapsigargin to enrich intracellular HA. Ratiometric phosphorescence imaging microscopy experiments demonstrated the ability of the probe for monitoring intracellular HA uptake. In addition, photoluminescence lifetime imaging microscopy techniques could be applied for visualization of HA within the RAW 264.7 cells, because the HA binding elongated the photoluminescence lifetime. Our study demonstrated the promising utility of inner-sphere interactions of phosphorescent Pt(II) complexes for detection of biological HA.
- Park, Gyurim,Yu, Seungyeon,Kim, Sinheui,Nah, Yoonseo,Son, Ahjeong,You, Youngmin
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p. 13985 - 13997
(2018/11/01)
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- Facile syntheses of histamine-and imidazole-4-propionic acid-derived room-temperature ionic liquids
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We report synthesis of histamine-and imidazole-4-propionic acid-based ionic liquids containing a variety of alkyl and aryl groups placed at the two different positions of the constituent imidazole ring in convenient steps in good yields.
- Dubey, Ravi Kant,Kumar, Neeraj,Jain, Rahul
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experimental part
p. 2207 - 2216
(2012/06/18)
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- Carbonic anhydrase i and II activation with mono- and dihalogenated histamine derivatives
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Mono- and dihalogenated histamine derivatives incorporating fluorine, chlorine and bromine have been prepared together with the corresponding boc-protected compounds at the aminoethyl group. They have been investigated as activators of the zinc enzyme carbonic anhydrase (CA, EC 4.2.1.1). The cytosolic human (h) isoforms hCA I and II were moderately activated by the boc-protected halogenated histamines and very effectively activated by the deprotected ones. Low nanomolar and subnanomolar hCA I and II activators have been detected for the first time, starting from histamine as lead which has an affinity of 2 μM against isoform I and of 125 μM against hCA II.
- Saada, Mohamed-Chiheb,Vullo, Daniela,Montero, Jean-Louis,Scozzafava, Andrea,Winum, Jean-Yves,Supuran, Claudiu T.
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p. 4884 - 4887
(2011/09/21)
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- Boiling water-catalyzed neutral and selective N-Boc deprotection
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A general protocol for removing Boc groups from various types of nitrogen is reported and a preliminary investigation of the reaction mechanism indicates that water acts as a dual acid/base catalyst at elevated temperature. The Royal Society of Chemistry 2009.
- Wang, Jia,Liang, Yan-Liang,Qu, Jin
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supporting information; experimental part
p. 5144 - 5146
(2009/12/08)
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- ELECTROCHEMICAL AFFINITY BIOSENSOR SYSTEM AND METHODS
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The present invention provides novel osmium-based electrochemical species for the detection of wide variety of analytes using immunological techniques. The present invention also provides diagnostic kits and test sensors supporting electrode structures that can be used with the osmium-based electrochemical species. The test sensor can be fabricated to support interdigitated arrays of electrodes that have been designed to provide amplification of the electrical signal amplification desired to analyze analytes that may be present at low concentrations.
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Page/Page column 65-66; Sheet 12
(2010/02/11)
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- Selective removal of the N-BOC protective group using silica gel at low pressure
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Selective removal of BOC groups from nitrogen atoms in conjugation with an aromatic or carbonyl groups, employing silica gel, is described.
- Apelqvist, Theresa,Wensbo, David
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p. 1471 - 1472
(2007/10/03)
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- SELECTIVE REMOVAL OF THE TERT-BUTOXYCARBONYL GROUP FROM SECONDARY AMINES: ZnBr2 AS THE DEPROTECTING REAGENT
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ZnBr2 in dichloromethane is a convenient reagent for mild and selective removal of the tert-butoxycarbonyl group from secondary amines.
- Nigam, Satish C.,Mann, Andre,Taddei, Maurizio,Wermuth, Camille-Georges
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p. 3139 - 3142
(2007/10/02)
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