Synthesis, characterization and derivatization of hydroxyl-functionalized iron(<scp>ii</scp>) bis(NHC) complexes
作者:Anja C. Lindhorst、Manuel Kaspar、Philipp J. Altmann、Alexander Pöthig、Fritz E. Kühn
DOI:10.1039/c7dt04774f
日期:——
hydroxyl-functionalized tetradentate NHC/pyridine hybrid ligand and the corresponding Ag(I) and Fe(II) complexes are presented. Spectroscopic and X-ray diffraction techniques are used for structural investigations and cyclic voltammetry measurements reveal interesting electronic properties. Transmetalation of the trinuclear Ag(I) complex (C1) yields a mononuclear and a dinuclear iron(II) bis(NHC) complex (C2
Preparation and Properties of Aluminum and Zinc Haloalcoholates
作者:Takashi Ueshima、Shimpei Tomita、Takeo Saegusa
DOI:10.1246/bcsj.41.1194
日期:1968.5
distilled nor sublimed even in vacuo. The usual aluminum alcoholates, such as ethoxide and isopropoxide, are easily distilled under reduced pressures. (2) The haloalcoholates are stronger Lewis acids than the usual alcoholates. The acid strength of some aluminumhaloalcoholates is even higher than triethylaluminum. The strong acid nature of the aluminumhaloalcoholate can be ascribed to the electron-withdrawing
Formation of etheno adducts of adenosine and cytidine from 1-halooxiranes. Evidence for a mechanism involving initial reaction with the endocyclic nitrogen atoms
作者:F. Peter Guengerich、Veronica D. Raney
DOI:10.1021/ja00029a041
日期:1992.1
The etheno derivatives of nucleic acid bases contain an additional ring and are of interest because of their useful fluorescence properties and their potential as mutagenic lesions in DNA. The mechanism of formation from 2-haloacetaldehydes is known to involve initial Schiff base formation at an exocyclic nitrogen; however, mechanisms of formation from the more relevant 1-substituted oxiranes have not been established. The reaction of N6-methyladenosine (5) with 1-chlorooxirane yielded the stable carbinolamine 7,8-dihydro-8-hydroxy-9-methyl-3-beta-D-ribofuranosylimidazo[2,1-i]purinium species (10), consistent with initial attack of the N1 atom of adenine at the methylene of 1-chlorooxirane. No products indicative of initial reaction at the N6 atom of adenine were found. Reaction of 2,2-dibromoethanol with adenosine or cytidine at pH 9.2 yielded 1,N6-ethenoadenosine (1) or 3,N4-ethenocytidine (2), respectively, presumably via the base-catalyzed formation of 1-bromooxirane from the bromohydrin. When reactions were done with 2,2-dibromo[1-C-13]ethanol, 1 contained label only at C-7 and 2 contained label only at C-3. A role for 2-bromoacetaldehyde in these reactions was ruled out by the lack of incorporation of deuterium from (H2O)-H-2 into 1 under conditions where the exchange of the methylene protons of 2-bromoacetaldehyde with the solvent was relatively rapid. The collective results are most consistent with a mechanism in which the basic endocyclic nitrogen (N1 of adenine or N3 of cytosine) reacts with the methylene carbon of the 1-halooxirane, and, after ring opening and loss of the leaving group, the resulting aldehyde reacts with the exocyclic nitrogen to form the additional ring.