Phase Separation As a Strategy Toward Controlling Dilution Effects in Macrocyclic Glaser-Hay Couplings
摘要:
Macrocycles are abundant in numerous chemical applications, however the traditional strategy for the preparation of these compounds remains cumbersome and environmentally damaging; involving tedious reaction set-ups and extremely dilute reaction media. The development of a macrocyclization strategy conducted at high concentrations is described which exploits phase separation of the catalyst and substrate, as a strategy to control dilution effects. Sequestering a copper catalyst in a highly polar and/or hydrophilic phase can be achieved using a hydrophilic ligand, T-PEG(1900), a PEGylated TMEDA derivative. Similarly, phase separation is possible when suitable copper complexes are soluble in PEG(400), a green and efficient solvent which can be utilized in biphasic mixtures for promoting macrocyclization at high concentrations. The latter phase separation technique can be exploited for the synthesis of a wide range of industrially relevant macrocycles with varying ring sizes and functional groups.
Preparation of biological labels with acetylenic linker arms
摘要:
The preparation of a series of fluorescent labels based on acridone, pyrene, fluorescein, dimedlylaminonaphthalenesulphonamide and tris-l,10-phenanthroline ruthenium and an enzymic label based on biotin with spacers containing a terminal acetylene is described. (C) 1997, Elsevier Science Ltd.
Copper‐Catalyzed Difluoromethylation of Alkyl Iodides Enabled by Aryl Radical Activation of Carbon–Iodine Bonds
作者:Aijie Cai、Wenhao Yan、Chao Wang、Wei Liu
DOI:10.1002/anie.202111993
日期:2021.12.20
An aryl radical activation strategy has been developed that can engage unactivated alkyliodides in copper-catalyzed Negishi-type cross-coupling reactions. The strategy is based on the largely overlooked yet highly efficient reactivity of aryl radicals to abstract iodine atoms from alkyliodides.
We report the synthesis of the first click-appended prodigiosene conjugates. Four prodigiosene conjugates of estradiol functionalised at the 7α-position were prepared, as were three prodigiosene conjugates of tamoxifen. The coupling between a prodigiosene and an 11-hydroxy estradiol derivative via an ether linkage was investigated, as was the 11- and 7-functionalisation of the estradiol core. The robustness
New myocardial imaging agents: stabilization of radioiodine as a terminal vinyl iodide moiety on tellurium fatty acids
作者:F. F. Knapp、M. M. Goodman、A. P. Callahan、L. A. Ferren、G. W. Kabalka、K. A. R. Sastry
DOI:10.1021/jm00363a014
日期:1983.9
To determine the myocardial uptake and retention properties of radioiodinated tellurium fatty acids, we prepared two new tellurium fatty acids in which iodine-125 has been chemically stabilized by attachment as a trans-vinyl iodide (I-CH = CH-R-Te-R'-COOH) and evaluated them in rats. Fabrication of 18-iodo-13-tellura-17-octadecenoic acid was accomplished by coupling 1,5-diiodo-1-pentene with sodium
The firsttotalsynthesis of the 15-epimer 1b of the naturally occurring acetogenin annonin I 1a is described. All stereogenic centres in the bis-THF subunit are controlled via successive Sharpless asymmetric epoxidations (AE). Alkyl side chains were attached directly to the core using alkyne-epoxide couplings.
描述了天然存在的产乙酸甘油酯Annnonin I 1a的15-受体1b的第一全合成。通过连续的Sharpless不对称环氧化(AE)控制bis-THF亚基中的所有立体异构中心。使用炔烃-环氧偶联剂将烷基侧链直接连接到核上。
Threading of various ‘U’ shaped bidentate axles into a heteroditopic macrocyclic wheel via Ni<sup>II</sup>/Cu<sup>II</sup> templation
functionalities (Axle1-Axle10) is investigated by using a heteroditopic amido-amine macrocyclic (MC) wheel via NiII or CuII metal ion templation. These bent shaped axles are the derivatives of 4, 4' substituted 2, 2' bipyridine, which are composed of various terminal groups like alkene, alkyne, bromide, hydroxyl and azide. Such metallo [2]pseudorotaxanes are well characterised by ESI-MS, EPR and FT-IR spectroscopic