Showing 1-30 of 1060 results for "deprotonations"
S L Ashok Kumar et al.
Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy, 113, 123-129 (2013-05-30)
Two novel heterocyclic thiosemicarbazone derivatives have been synthesized, and characterized, by means of spectroscopic and single crystal X-ray diffraction methods. Their chromophoric-fluorogenic response towards anions in competing solvent dimethyl sulfoxide (DMSO) was studied. The receptor shows selective recognition towards fluoride...
Yuelin Song et al.
Journal of chromatography. A, 1406, 136-144 (2015-06-25)
Homolog-focused profiling is a favored option to bridge targeted metabolomics toward non-targeted metabolomics. In current study, an attempt was made for the large-scale ginsenoside-specific analysis in ginseng (G) and American ginseng (AG). When formic acid (0.1%, v/v) was introduced as...
Xiaobing Wan et al.
Journal of the American Chemical Society, 128(37), 12046-12047 (2006-09-14)
A unique method was discovered to construct polysubstituted pyrroles via an unprecedented multiple deprotonations/deaminations process from commercially available phenethylamines. During this transformation, twelve bonds were broken and five new bonds were constructed.
Alfons Penzkofer et al.
International journal of molecular sciences, 20(17) (2019-08-24)
QuasAr1 is a fluorescent voltage sensor derived from Archaerhodopsin 3 (Arch) of Halorubrum sodomense by directed evolution. Here we report absorption and emission spectroscopic studies of QuasAr1 in Tris buffer at pH 8. Absorption cross-section spectra, fluorescence quantum distributions, fluorescence...
Adam A Wallace et al.
The journal of physical chemistry. A, 124(38), 7768-7775 (2020-08-28)
We report a photoelectron imaging study of gas-phase deprotonation of isoxazole in which spectroscopic data are compared to the results of electronic structure calculations for the anion products corresponding to each of three possible deprotonation sites. The observed photoelectron spectra...
Adela Dudić et al.
Biological chemistry, 400(7), 927-938 (2019-03-25)
Quinoxalinediones are an important class of competitive antagonists at ionotropic glutamate receptors (iGluRs), where they are widely used to block α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) and kainate receptor responses. In this study we utilize two prototypic quinoxalinedione antagonists, namely DNQX and CNQX...
Miroslawa Dauter et al.
Acta crystallographica. Section D, Biological crystallography, 67(Pt 12), 1073-1075 (2011-11-29)
Many different proteins utilize the chemical energy provided by the cofactor adenosine triphosphate (ATP) for their proper function. A number of structures in the Protein Data Bank (PDB) contain adenosine 5'-(β,γ-imido)triphosphate (AMPPNP), a nonhydrolysable analog of ATP in which the...
Organoselenium chemistry. 4. Deprotonations with potassium diisopropylamide-lithium tert-butoxide. Alkylation of 1-(phenylseleno) alkenes and bis (phenylseleno) acetals.
Raucher S and Koolpe G A
The Journal of Organic Chemistry, 43(19), 3794-3796 (1978)
Deprotonation of benzoxazole and oxazole using lithium magnesates
Bayh O, et al.
The Journal of Organic Chemistry, 70(13), 5190-5196 (2005)
Cheng-Yi Chiang et al.
PloS one, 10(7), e0134108-e0134108 (2015-07-29)
Chromoproteins (CPs) have unique colors and can be used in biological applications. In this work, a novel blue CP with a maximum absorption peak (λmax) at 608 nm was identified from the carpet anemone Stichodactyla gigantea (sgBP). In vivo expression...
Matthew M Meyer et al.
The Journal of organic chemistry, 75(12), 4274-4279 (2010-05-26)
Deprotonation of 2-adamantanone (1) in the gas phase affords the corresponding beta-enolate anion. This ion was independently prepared by the fluoride-induced desilylation of 4-trimethylsilyl-2-adamantanone, and its reactivity and thermodynamic properties were measured (DeltaH degrees(acid) = 394.7 +/- 1.4, EA =...
Tatsushi Imahori
Yakugaku zasshi : Journal of the Pharmaceutical Society of Japan, 124(8), 509-517 (2004-08-07)
A novel type of deprotonative functionalization of aromatics was accomplished with a phosphazene base (t-Bu-P4 base). For various nitrogen heteroaromatics and benzene derivatives, deprotonative 1,2-additions proceeded with the t-Bu-P4 base and ZnI(2) as an additive in the presence of carbonyl...
Yinsheng Wang et al.
Journal of the American Society for Mass Spectrometry, 13(10), 1190-1194 (2002-10-22)
2-Aminoimidazolone and 5-formyluracil are major one-electron photooxidation products of guanine and thymine in oligodeoxynucleotides (ODNs). Herein we report the HPLC isolation and tandem mass spectrometric characterization of ODNs carrying those types of base modifications. Collision-activated dissociation (CAD) of the deprotonated...
Zhe Zhou et al.
Journal of the American Chemical Society, 139(1), 115-118 (2016-12-23)
Herein we disclose a novel method for the facile transfer of primary (-NH2) and secondary amino groups (-NHR) to heteroaryl- as well as arylcuprates at low temperature without the need for precious metal catalysts, ligands, excess reagents, protecting and/or directing...
Chuanjiang Hu et al.
Inorganic chemistry, 52(6), 3170-3177 (2013-03-09)
The effects of the deprotonation of coordinated imidazole on the vibrational dynamics of five-coordinate high-spin iron(II) porphyrinates have been investigated using nuclear resonance vibrational spectroscopy. Two complexes have been studied in detail with both powder and oriented single-crystal measurements. Changes...
David Salom et al.
Proceedings of the National Academy of Sciences of the United States of America, 103(44), 16123-16128 (2006-10-25)
The changes that lead to activation of G protein-coupled receptors have not been elucidated at the structural level. In this work we report the crystal structures of both ground state and a photoactivated deprotonated intermediate of bovine rhodopsin at a...
Gandrath Dayaker et al.
Chemical communications (Cambridge, England), 46(16), 2862-2864 (2010-04-07)
A mixed lithium-cadmium amide and a combination of lithium and zinc amides were reacted with a range of ferrocenes; deprotonative mono- or dimetallation in general occurred chemoselectively at room temperature, as evidenced by subsequent quenching with iodine.
Yufang Liu et al.
Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy, 79(1), 213-218 (2011-03-23)
The combined density functional theory (DFT) and time-dependent density functional theory (TDDFT) method was used to study the electronic spectral properties of different deprotonated forms of esculetin. By comparing the experimental absorption and fluorescence bands with the calculated electronic spectra...
Claudia Köthe et al.
Inorganic chemistry, 51(18), 9740-9747 (2012-09-07)
The reaction of [L(tBu)Ni(OEt(2))] (where L(tBu) = [HC(C(t)BuNC(6)H(3)((i)Pr)(2))(2)](-)) with phenylhydrazine leads to the phenylhydrazido(1-) complex [L(tBu)Ni(η(2)-NPhNH(2))] (1) with concomitant formation of H(2). Treatment of 1 with potassium graphite in the presence of crown ether again leads to H(2) evolution and...
Sven Heiles et al.
Physical chemistry chemical physics : PCCP, 20(23), 15641-15652 (2018-05-31)
Structures of deprotonated Cys, Asp, Glu, Phe, Pro, His homo dimers as well as [2Cys - 3H]-, [Asp + Glu - H]- and [2Glu - 2H + Na]- are investigated with infrared multiple-photon dissociation (IRMPD) spectroscopy between 650 and 1850...
Ting Wang et al.
Structure (London, England : 1993), 21(2), 290-297 (2013-02-12)
Despite extensive investigation, the precise mechanism controlling the opening of the cytoplasmic proton uptake pathway in bacteriorhodopsin (bR) has remained a mystery. From an analysis of the X-ray structure of the D96G/F171C/F219L triple mutant of bR and 60 independent molecular...
Ricardo Vessecchi et al.
Rapid communications in mass spectrometry : RCM, 24(14), 2101-2108 (2010-06-17)
Electrospray ionization mass spectrometric analysis of lapachol (2-hydroxy-3-(3-methyl-2-butenyl)-1,4-naphthoquinone) was accomplished in order to elucidate the gas-phase dissociation reactions of this important biologically active natural product. The occurrence of protonated and cationized species in the positive mode and of deprotonated species...
Viktoria H Gessner et al.
Journal of the American Chemical Society, 130(44), 14412-14413 (2008-10-10)
TMEDA and its ethyl-substituted analogue, TEEDA, show a different behavior toward the deprotonation with lithiumalkyls. While TMEDA mainly undergoes alpha-lithiation of its methyl group, TEEDA shows selective beta-lithiation with following elimination of ethene. The crystal structure of the monomeric intermediate...
Roberto Fernandez-Maestre et al.
Rapid communications in mass spectrometry : RCM, 30(11), 1332-1338 (2016-05-14)
When dopants are introduced into the buffer gas of an ion mobility spectrometer, spectra are simplified due to charge competition. We used electrospray ionization to inject tetrahydrofuran-2-carbonitrile (F, 2-furonitrile or 2-furancarbonitrile) as a buffer gas dopant into an ion mobility...
Liangliang Zhang et al.
International journal of molecular sciences, 19(10) (2018-10-14)
In the present paper, methyl gallate (MeG), a simple polyphenol and also the monomer of hydrolysable tannins, was selected to study the deprotonation process for the hydroxyls of the galloyl group by the combined use of spectroscopic measurements and quantum...
Deprotonation of thiophenes using lithium magnesates
Bayh O, et al.
Tetrahedron, 61(20), 4779-4784 (2005)
Deprotonation of furans using lithium magnesates
Mongin F, et al.
Tetrahedron Letters, 46(46), 7989-7992 (2005)
S Sunil Kumar et al.
The journal of physical chemistry. A, 115(38), 10383-10390 (2011-07-23)
The UV photodissociation dynamics of deprotonated 2'-deoxyadenosine 5'-monophosphate ([5'-dAMP-H](-)) has been studied using a unique technique based on the coincident detection of the ion and the neutral fragments. The observed fragment ions are m/z 79 (PO(3)(-)), 97 (H(2)PO(4)(-)), 134 ([A-H](-))...
Gaku Akimoto et al.
The Journal of organic chemistry, 83(21), 13498-13506 (2018-10-23)
The reaction pathways of lithium 2,2,6,6-tetramethylpiperidide (LiTMP)-mediated deprotonative metalation of methoxy-substituted arenes were investigated. Importantly, it was experimentally observed that, whereas TMEDA has no effect on the course of the reactions, the presence of more than the stoichiometric amount of...
José L Castro et al.
Langmuir : the ACS journal of surfaces and colloids, 28(24), 8926-8932 (2012-01-25)
The surface-enhanced raman scattering (SERS) of benzoic acid/benzamide and salicylic acid/salicylamide on silver colloids show important wavenumber shifts with respect to the Raman spectrum of the band assigned to mode 1;ν(ring) when adsorbed on the metal surface (ca. +50 cm(-1))....

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