4392-83-0Relevant academic research and scientific papers
Substrate-directed lewis-acid catalysis for peptide synthesis
Muramatsu, Wataru,Hattori, Tomohiro,Yamamoto, Hisashi
supporting information, p. 12288 - 12295 (2019/08/20)
A Lewis-acid-catalyzed method for the substrate-directed formation of peptide bonds has been developed, and this powerful approach is utilized for the new "remote" activation of carboxyl groups under solvent-free conditions. The presented method has the following advantages: (1) the high-yielding peptide synthesis uses a tantalum catalyst for any amino acids; (2) the reaction proceeds without any racemization; (3) the new substrate-directed chemical ligation using the titanium catalyst is applicable to convergent peptide synthesis. These advantages overcome some of the unresolved problems in classical peptide synthesis.
Geometry matters: Inverse cytotoxic relationship for: Cis / trans -Ru(II) polypyridyl complexes from cis / trans -[PtCl2(NH3)2]
Wachter, Erin,Zamora, Ana,Heidary, David K.,Ruiz, José,Glazer, Edith C.
supporting information, p. 10121 - 10124 (2016/08/18)
Two thermally activated ruthenium(ii) polypyridyl complexes, cis-Ru(bpy)2Cl2 and trans-Ru(qpy)Cl2 were investigated to determine the impact of the geometric arrangement of the exchangable ligands on the potential of the compounds to act as chemotherapeutics. In contrast to the geometry requirements for cisplatin, trans-Ru(qpy)Cl2 was 7.1-9.5× more cytotoxic than cis-Ru(bpy)2Cl2. This discovery could open up a new area of metal-based chemotherapeutic research.
Reaction of 2-pyridyllithium with azine N-oxides. Simple and convenient method for the synthesis of 2,2′-bipyridine 1-oxide and 2,2′:6′,2″:6″2?-tetrapyridine 1′-oxide
Kovalev,Rusinov,Chupakhin
experimental part, p. 176 - 181 (2010/02/28)
In the reaction of 2-pyridyllithium with quinoline 1-oxide and isoquinoline 2-oxide a nucleophilic substitution of hydrogen occurs to form the corresponding pyridin-2-ylquinolines. A dimerization of the substrate occurs with pyridine 1-oxide, 2,2′-bipyridine 1-oxide or quinoxaline N-oxide. A similar dimerization in good yield occurs when treating azine N-oxides with tert-butyllithium and this serves as a simple and convenient method for preparing bi- and tetrapyridines.
Bis-qtpy (qtpy = 2,2′:6′,2″:6″,2?- quaterpyridine) metal complexes, [M(qtpy)2]2+
Dell' Amico, Daniela Belli,Calderazzo, Fausto,Curiardi, Matteo,Labella, Luca,Marchetti, Fabio
, p. 5459 - 5465 (2008/10/09)
Reactions of perchlorates of iron(II), nickel(II), and zinc(II) with 2,2′:6′,2″:6″,2?-quaterpyridine (qtpy) gave the first crystallographically established bis-qtpy metal complexes of formula [M(qtpy)2][ClO4]2 (M = Fe, Ni, Zn). Coordination of two terdentate quaterpyridines to the same center produces a distorted octahedron of six nitrogen atoms around the metal, leaving two pendant pyridyl groups, one for each quaterpyridine. For the diamagnetic zinc system, an NMR investigation has been carried out in order to establish the conditions to obtain the intermediate mono-qtpy complex, of formula [Zn(qtpy)(H 2O)2][ClO4]2, which has also been crystallographically established. The corresponding hexafluorophosphate derivatives [M(qtpy)2][PF6]2 (M = Ni and Zn) were prepared in DMF at room temperature.
The use of Ni(CO)2(PPh3)2 in aryl and pyridyl coupling reactions
Leadbeater, Nicholas E.,Resouly, Sarah M.
, p. 4243 - 4246 (2007/10/03)
The zerovalent nickel complex Ni(CO)2(PPh3)2 has been used for the coupling of aryl halides to form biaryls and for the coupling of bromopyridines to form polypyridines. The effects of solvent, halide and substituents have also been investigated.
A new and simple 'LEGO' system for the synthesis of 2,6-oligopyridines
Pabst, Gunther R.,Sauer, Juergen
, p. 6687 - 6690 (2007/10/03)
The condensation of α-arylglyoxals with carboxamidrazones 1 - 2 is the best method for the synthesis of aryl or hetaryl substituted 1,2,4-triazines 3 - 4. These 1,2,4-triazines can be easily transformed to pyridines by [4+2] cycloaddition with bicyclo[2.2.1]hepta-2,5-diene followed by [4+2] cycloreversions of nitrogen and cyclopentadiene. This reaction sequence offers a new, simple and general access to 2,6-oligopyridines 8 - 11.
2,2′:6′,2″:6″,2?-Quaterpyridine (qtpy): A
Constable, Edwin C.,Elder, Susan M.,Hannon, Michael J.,Martin, Avelino,Raithby, Paul R.,Tocher, Derek A.
, p. 2423 - 2433 (2007/10/03)
The co-ordination behaviour of 2,2′:6′,2″:6″,2?-quaterpyridine (qtpy) has been systematically studied. Double-helical dinuclear complexes were only obtained with ions bearing a low charge or a low charge-to-radius ratio and which have no electronically imposed preference for geometries in which the ligand can present a planar donor set. The double-helical complexes [Cu2(qtpy)2][PF6]2 and [Ag2(qtpy)2][BF4]2 have been structurally characterised, as have the mononuclear species [Ni(qtpy)(OH2)2][BF4]2 and [Pd(qtpy)][PF6]2. Complexes with zinc(II) and cadmium(II) are mononuclear but it is suggested that a double-helical dinuclear complex is formed with mercury(II).
Ipso substitution of 2-alkylsulfinylpyridine by 2-pyridyllithium; a new preparation of oligopyridine and their bromomethyl derivatives
Uenishi,Tanaka,Wakabayashi,Oae,Tsukube
, p. 4625 - 4628 (2007/10/02)
Unsymmetrical and symmetrical 2,2'-bipyridines have been prepared. The methods applied are new and offer efficient syntheses of higher oligopyridines and their bromomethyl derivatives.
A Convenient Preparation of 2,2':6',2":6",2'"-Quaterpyridine; The Crystal and Molecular Structures of 2,2':6',2":6",2'"-Quaterpyridine and Bis(acetonitrile)-(2,2':6',2":6",2'"-quaterpyridine)nickel(II)Hexafluorophosphate-Acetonitrile(1/1)
Constable, Edwin C.,Elder, Susan M.,Healy, John,Tocher, Derek A.
, p. 1669 - 1674 (2007/10/02)
2,2':6',2":6",2'"-Quaterpyridine has been prepared in 40-45percent yield by nickel(0) coupling of a 6-halogeno-2,2'-bipyridine.The reaction initially yields a nickel(II) complex of 2,2':6',2":6",2'"-quaterpyridine which may be demetallated by treatment with NaCN.The crystal and molecular structures of 2,2':6',2":6",2'"-quaterpyridine 1/n, Z= 2> and bis(acetonitrile)-(2,2':6',2":6",2'"-quaterpyridine)nickel(II) hexafluorophosphate-acetonitrile (1/1) have been determined.The free ligand is essentially planar with transoid arrangements of the pyridyl rings as observed in 2,2'-bipyridine.The nickel complex is approximately octahedral with the 2,2':6',2":6",2'"-quaterpyridine occupying the equatorial sites; the Ni-N distances to the terminal pyridine rings are longer than those to the inner rings.
