37868-93-2Relevant academic research and scientific papers
The First Zero-Length Mass Spectrometry-Cleavable Cross-Linker for Protein Structure Analysis
Hage, Christoph,Iacobucci, Claudio,Rehkamp, Anne,Arlt, Christian,Sinz, Andrea
, p. 14551 - 14555 (2017)
Combining the properties of a zero-length cross-linker with cleavability by tandem mass spectrometry (MS/MS) poses great advantages for protein structure analysis using the cross-linking/MS approach. These include a reliable, automated data analysis and the possibility to obtain short-distance information of protein 3D-structures. We introduce 1,1′-carbonyldiimidazole (CDI) as an easy-to-use and commercially available, low-cost reagent that ideally fulfils these features. CDI bridges primary amines and hydroxy groups in proteins with the lowest possible spacer length of one carbonyl unit (ca. 2.6 ?). The cross-linking reaction can be conducted under physiological conditions in the pH range between 7.2 and 8. Urea and carbamate cross-linked products are cleaved upon collisional activation during MS/MS experiments generating characteristic product ions, greatly improving the unambiguous identification of cross-links. Our innovative analytical concept is exemplified and applied for bovine serum albumin (BSA), wild-type tumor suppressor p53, an intrinsically disordered protein, and retinal guanylyl cyclase activating protein-2 (GCAP-2).
Metal-free, Mild, and Selective Synthesis of Bis(pyrazolyl)alkanes by Nucleophile-Catalyzed Condensation
Tansky, Maxym,Gu, Zipeng,Comito, Robert J.
, p. 1601 - 1611 (2021/01/14)
Bis(pyrazolyl)alkanes are a prolific class of ligands for catalysis, accessible by the condensation between bis(pyrazolyl)methanones and carbonyls. In this report, we describe a nucleophile-catalyzed innovation on this condensation that avoids the transition metals, high temperatures, reagent excess, and air-sensitive reagents common among the existing protocols. Significantly, this method accommodates sterically hindered and electronically diverse pyrazoles and aldehydes, applicable for systematic ligand optimization. Furthermore, our scope includes azoles and bridging functional groups previously unreported for this reaction, promising for new heteroscorpionate catalysts. We provide the first direct evidence for an elusive reaction intermediate and characterize the most complete mechanism for this condensation.
Synthesis and reactivity in ethylene oligomerization by heteroscorpionate dibromonickel(II) complexes
Zubkevich, Sergei V.,Gagieva, Svetlana Ch.,Tuskaev, Vladislav A.,Dorovatovskii, Pavel V.,Khrustalev, Victor N.,Sizov, Alexandr I.,Bulychev, Boris M.
, p. 58 - 67 (2017/01/06)
Novel heteroscorpionate ligands were synthesized by a Peterson rearrangement during the reaction of 2-pyridinecarboxaldehyde (or 2-quinolinecarboxaldehyde) and 1,1-carbonyl-bis(pyrazoles). Nickel(II) dibromide reacts with these ligands in THF to give the heteroscorpionate dibromo complexes of general formula LNiBr2. Crystal structures of two full-sandwich heteroscorpionate Ni(II) complexes were determined. Preliminary studies of catalytic activity in ethylene oligomerization using different organoaluminum cocatalysts were performed. The addition of one equivalent of triphenylphosphine resulted in increased catalytic activity for most examples. The catalyst system of (2-[bis(3,5-dimethylpyrazol-1-yl)methyl]pyridine nickel(II) dibromide/Et2AlCl/PPh3dimerized ethylene with an activity of 650?g oligomer mol?1?Ni?h?1while the share of 1-butene in the mixture has reached 75%. Tris(3,5-dimethylpyrazol-1-yl)methyl nickel(II) dibromide, activated by Et2AlCl/PPh3produced isobutylene (75% of the butene fraction).
Titanium and zirconium compounds stabilized by coordination of heteroscorpionate [N,N,O]-donor ligands. Synthesis, characterization and polymerization activity
Alesso, Giuseppe,Tabernero, Vanessa,Cuenca, Tomás
, p. 202 - 210 (2012/11/06)
The bis(pyrazol-1-yl)methane compounds [(2-hydroxyphenyl)bis(pyrazol-1-yl) methane (4) bpzmpH, (3,5-di-tert-butyl-2-hydroxyphenyl)bis(pyrazol-1-yl)methane (5) bpzmtBu2pH, (2-hydroxyphenyl)bis(3,5-dimethyl-pyrazol-1-yl) methane (6) Me2bpzmpH, (3,5-di-tert-butyl-2-hydroxyphenyl)bis(3,5- dimethyl-pyrazolyl)methane (7) Me2bpzmtBu2pH, (2-hydroxyphenyl)bis(4-methyl-pyrazolyl)methane (8) MebpzmpH and (3,5-di-tert-butyl-2-hydroxyphenyl)bis(4-methyl-pyrazolyl)methane (9) MebpzmtBu2pH] as heteroscorpionate precursor ligands have been prepared by reaction of the corresponding bis(pyrazol-1-yl)ketone (1), bis(3,5-dimethylpyrazol-1-yl)ketone (2) and bis(4-methylpyrazol-1-yl)ketone (3) with the appropriate salicylaldehyde derivative. The coordination of these molecules to titanium and zirconium compounds containing a cyclopentadienyl ligand has been studied. TiCpRCl3 (CpR = η5-C5H5 (Cp); η5-C 5H4SiMe3 (Cp′); η5-C 5Me5 (Cp*)) reacts with 4-9 in the presence of 2.5 equiv of NEt3, in toluene at room temperature, through an alcoholysis process to give the monocyclopentadienyl heteroscorpionate dichloro complexes TiCpRLCl2 [CpR = Cp, L = bpzmp (10), Me2bpzmtBu2p (11), MebpzmtBu2p (12); CpR = Cp′, L = Me2bpzmtBu2p (13); CpR = Cp*, L = bpzmp (14), Me2bpzmtBu2p (15)] (Scheme 2). Treatment of TiCp*Me3 with 4, 6 and 8 affords the dimethyl complexes TiCp*LMe2 [L = bpzmp (16), Me2bpzmp (17), Mebpzmp (18)]. Analogous dichloro ZrCpLCl2 [L = bpzmp (19), bpzmtBu2p (20), Me2bpzmp (21), MebpztBu2p (22)] and dibenzyl ZrCpLBz2 [L = bpzmp (23), bpzmtBu2p (24), Me2bpzmp (25), MebpzmtBu2p (26)] zirconium complexes have also been prepared by reaction of ZrCpCl3 in THF or ZrCpBz3 in toluene with 4, 5, 6 and 8 at room temperature. From spectroscopic data tetrahedral structures in solution with a κ1-O coordination mode are suggested for the titanium complexes, while distorted octahedral geometries with a κ3-N,N, O coordination are proposed for the zirconium derivatives. Fluxional exchange between coordinated and non-coordinated pyrazolate rings is concluded in some zirconium compounds, depending on the electronic and steric effects imposed by the substituents of the heteroscorpionate ligands. Preliminary studies of catalytic activity for ethylene polymerization using sMAO as cocatalyst were performed. The complexes proved to be moderate catalysts due to loss of the scorpionate ligand.
(Arene)ruthenium(II) complexes containing substituted bis(pyrazolyl)methane ligands - Catalytic behaviour in transfer hydrogenation of ketones
Carrion, M. Carmen,Jalon, Felix A.,Manzano, Blanca R.,Rodriguez, Ana M.,Sepulveda, Francisco,Maestro, Miguel
, p. 3961 - 3973 (2008/03/12)
A new and safer methodology has been developed for the synthesis of bis(pyrazol-1-yl)methane ligands (NN). Several ligands containing different phenyl groups on the central carbon atom have been obtained. Ruthenium derivatives of the type [Ru(arene)Cl(NN)]BPh4 (arene = benzene, p-cymene) have been synthesised using these ligands. One or two isomers that differ regarding the axial or equatorial disposition of the phenyl group on the metallacycle have been obtained. Their formation is rationalised by considering steric effects. The structures of five derivatives were determined by X-ray diffraction. In four complexes the phenyl substituent is in the axial disposition of the metallacycle and in one case in the equatorial orientation. The dihedral angle formed by the planes of the two pyrazole rings is always bigger for the complexes containing unsubstituted pyrazolyl heterocycles. The behaviour of the new derivatives in the transfer hydrogenation of benzophenone in the presence of KOH was studied. The benzene derivatives showed higher activity than the p-cymene complexes. A marked and positive effect of the methyl groups on the pyrazolyl rings was observed. The effect of the substituents on the benzyl carbon atom was also important. It has been observed that the benzophenone hydrogenation was possible without the addition of complexes. The effect of the KOH concentration was evaluated and a concentration that leads to negligible conversion in a base-only process was chosen. Wiley-VCH Verlag GmbH & Co. KGaA, 2007.
Substituted heterocyclylisoquinolinium salts and compositions and method of use thereof
-
, (2008/06/13)
Substitutued heterocyclylisoquinolinium salts, pharmaceutical compositions containing them and methods for the treatment or prevention of neurodegenerative disorders or neurotoxic injuries utilizing them.
Substituted 6,11-ethano-6,11-dihydrobenzo[b] quinolizinium salts and compositions and methods of use thereof
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, (2015/04/15)
Substituted 6,11-ethano-6,11-dihydrobenzo[b]quinolizinium salts, pharmaceutical compositions containing them, and methods for the treatment of neurodegenerative disorders or neurotoxic injuries utilizing them, wherein the substituted 6,11-ethano-6,11-dihydrobenzo[b]quinolizinium salts have the formula: STR1 wherein: R1, R2, R3, R4, R5, R6, R7, X and p are as defined in the specification.
The synthesis of tripodal nitrogen donor ligands and their characterization as PdIIMe2 and PdIIIMe derivatives
Byers, Peter K.,Canty, Allan J.,Honeyman, Thomas
, p. 417 - 427 (2007/10/02)
New tripod ligands containing pyridin-2-yl (py), N-methylimidazol-2-yl (mim), and pyrazol-1-yl (pz) groups have been made by addition of 2-bromopyridine to deprotonated (py)(mim)CH2 or (mim)2CH2 to form (py)2(mim)CH and (py)(mim)2CH, or by simple condensation reactions of (pz)2CO with (mim)CHO or (py)CHO to form (pz)2(mim)CH and (pz)2(py)CH.The ligands may have general application in coordination and organometallic chemistry, especially bis(pyrazol-1-yl)(pyridin-2-yl)methane , which can be readily synthesized and is an unsymmetrical tripod closely relatedto (pz)3CH and (py)3CH.Dimethylpalladium(II) and methyl(iodo)palladium(II) complexes of the ligands have been isolated, and compared with complexes of (pz)3CH, (py)3CH and (pz)4C.
