Site-Selective Monotitanation of Dialkynylpyridines and Its Application for Preparation of Highly Fluorescent π-Conjugated Oligomers
摘要:
Reaction of Ti(O-i-Pr)(4)/2i-PrMgCl reagent with 2,n-bis[(trimethylsilyl)ethynyl]pyridines, where n is 3, 4, 5, and 6, or with 3,4-bis[(trimethylsilyl)ethynyl]pyridines, proceeded with excellent site-selectivity to afford the corresponding monotitanated complex. Synthetic application of the reaction was demonstrated by an efficient preparation of pi-conjugated oligomers having pyridine and enyne units alternately, which possess intense blue fluorescence emission.
Regiochemistry in the deprotonation of bromopyridines was found to be greatly influenced by the choice of metal amide base, and DA-zincate and TMP-zincate turned out to be excellent complementary practical agents for regioselective metalation of bromopyridines.
Homoleptic lithium tri‐ and tetraalkyl zincates were reacted with a set of bromopyridines. Efficient and chemoselective bromine–metal exchanges were realized at roomtemperature with a substoichiometric amount of nBu4ZnLi2⋅TMEDA reagent (1/3 equiv; TMEDA=N,N,N′,N′‐tetramethylethylenediamine). This reactivity contrasted with that of tBu4ZnLi2⋅TMEDA, which was inefficient below one equivalent. DFT calculations
Ruthenium half-sandwich complexes as protein kinase inhibitors: derivatization of the pyridocarbazole pharmacophore ligand
作者:Nicholas Pagano、Jasna Maksimoska、Howard Bregman、Douglas S. Williams、Richard D. Webster、Feng Xue、Eric Meggers
DOI:10.1039/b700433h
日期:——
A general route to ruthenium pyridocarbazole half-sandwich complexes is presented and applied to the synthesis of sixteen new compounds, many of which have modulated protein kinase inhibition properties. For example, the incorporation of a fluorine into the pyridine moiety increases the binding affinity for glycogen synthase kinase 3 by almost one order of magnitude. These data are supplemented with cyclic voltammetry experiments and a protein co-crystallographic study.
Deprotonative Metalation of Chloro- and Bromopyridines Using Amido-Based Bimetallic Species and Regioselectivity-Computed CH Acidity Relationships
作者:Katia Snégaroff、Tan Tai Nguyen、Nada Marquise、Yury S. Halauko、Philip J. Harford、Thierry Roisnel、Vadim E. Matulis、Oleg A. Ivashkevich、Floris Chevallier、Andrew E. H. Wheatley、Philippe C. Gros、Florence Mongin
DOI:10.1002/chem.201101993
日期:2011.11.18
A series of chloro‐ and bromopyridines have been deprotometalated by using a range of 2,2,6,6‐tetramethylpiperidino‐based mixed lithium–metal combinations. Whereas lithium–zinc and lithium–cadmium bases afforded different mono‐ and diiodides after subsequent interception with iodine, complete regioselectivities were observed with the corresponding lithium–copper combination, as demonstrated by subsequent
Ligand‐Enabled β‐Methylene C(sp
<sup>3</sup>
)−H Arylation of Masked Aliphatic Alcohols
作者:Guoqin Xia、Zhe Zhuang、Luo‐Yan Liu、Stuart L. Schreiber、Bruno Melillo、Jin‐Quan Yu
DOI:10.1002/anie.202000632
日期:2020.5.11
salicylic-aldehyde-derived L,X-type directing group with an electron-deficient 2-pyridone ligand to enable the β-methylene C(sp3 )-H arylation of aliphaticalcohols, which has not been possible previously. Notably, this protocol is compatible with heterocycles embedded in both alcohol substrates and aryl coupling partners. A site- and stereo-specific annulation of dihydrocholesterol and the synthesis of a key
On‐Surface Reactive Planarization of Pt(II) Complexes
作者:Jindong Ren、Marvin Cnudde、Dana Brünink、Stefan Buss、Constantin G. Daniliuc、Lacheng Liu、Harald Fuchs、Cristian A. Strassert、Hong‐Ying Gao、Nikos L. Doltsinis
DOI:10.1002/anie.201906247
日期:2019.10.21
A series of Pt(II) complexes with tetradentate luminophores has been designed, synthesized, and deposited on coinage metal surfaces with the aim to produce highly planar self-assembled monolayers. Low-temperature scanning tunneling microscopy (STM) and density functional theory (DFT) calculations reveal a significant initial nonplanarity for all complexes. A subsequent metal-catalyzed separation of