Recyclable Pd2dba3/XPhos/PEG-2000 System for Efficient Boryl­ation of Aryl Chlorides: Practical Access to Aryl Boronates

Synthesis ◽  
2021 ◽  
Author(s):  
Mingzhong Cai ◽  
Bin Huang ◽  
Chengkai Luo ◽  
Caifeng Xu
Keyword(s):  
Ethylene Glycol ◽  
Functional Group ◽  
Catalytic Efficiency ◽  
Poly Ethylene Glycol ◽  
Efficient Catalyst ◽  
Aryl Chlorides ◽  
Reaction Proceeds ◽  
Simple Extraction ◽  
Poly Ethylene

AbstractPd2dba3/XPhos in poly(ethylene glycol) (PEG-2000) is shown to be a highly stable and efficient catalyst for the borylation of aryl chlorides with bis(pinacolato)diboron. The borylation reaction proceeds smoothly at 110 °C, delivering a wide variety of aryl boronates in good to excellent yields with high functional group tolerance. The crude products were easily isolated via simple extraction of the reaction mixture with cyclohexane. Moreover, both expensive Pd2dba3 and XPhos in PEG-2000 system could be readily recycled and reused more than six times without loss of catalytic efficiency.

scholarly journals Catalytic activity of non-cross-linked microcrystals of aspartate aminotransferase in poly(ethylene glycol)

1983 ◽  
Vol 211 (2) ◽  
pp. 427-434 ◽  
Author(s):  
H Kirsten ◽  
P Christen
Keyword(s):  
Ethylene Glycol ◽  
Aspartate Aminotransferase ◽  
Crystal Packing ◽  
Catalytic Efficiency ◽  
Crystallographic Analysis ◽  
Poly Ethylene Glycol ◽  
Molar Activity ◽  
Kinetic Tests ◽  
Stokes Radius ◽  
Poly Ethylene

The molar activity of crystalline mitochondrial aspartate aminotransferase is decreased to 10% of that of the enzyme in solution. The activity was measured in suspensions of non-cross-linked microcrystals (average dimensions 22 microns X 5 microns X 0.8 microns) in 30% (w/v) poly(ethylene glycol). Kinetic tests ruled out the possibility that diffusion of the substrate in the crystals is rate-limiting. The observed decrease in catalytic efficiency can be attributed exclusively to crystal-packing effects. A direct inhibition by poly(ethylene glycol) is excluded because poly(ethylene glycol), with average Mr 6000, cannot penetrate the liquid channels of the crystals, owing to its large Stokes radius. The crystals examined were triclinic and of the same habit as those used for high-resolution X-ray-crystallographic analysis [Ford, Eichele & Jansonius (1980) Proc. Natl. Acad. Sci. U.S.A. 77, 2559-2563]. The catalytic competence of crystalline aspartate aminotransferase confirms the relevance of the spatial model of this protein for the elucidation of its mechanism of action.

N-Heterocyclic carbene ligands bearing poly(ethylene glycol) chains: effect of the chain length on palladium-catalyzed coupling reactions employing aryl chlorides

2015 ◽  
Vol 51 (98) ◽  
pp. 17382-17385 ◽  
Author(s):  
Tetsuaki Fujihara ◽  
Takahiro Yoshikawa ◽  
Motoi Satou ◽  
Hidetoshi Ohta ◽  
Jun Terao ◽  
...  
Keyword(s):  
Ethylene Glycol ◽  
Chain Length ◽  
Heterocyclic Carbenes ◽  
Coupling Reactions ◽  
Poly Ethylene Glycol ◽  
Carbene Ligands ◽  
Aryl Chlorides ◽  
Palladium Catalyzed ◽  
Poly Ethylene

N-Heterocyclic carbenes bearing poly(ethylene glycol) chains of different lengths have been employed as ligands in palladium-catalyzed coupling reactions of aryl chlorides.

Biomedical Applications of Gold Nanoparticles Functionalized Using Hetero-Bifunctional Poly(ethylene glycol) Spacer

2004 ◽  
Vol 845 ◽  
Author(s):  
Wei Fu ◽  
Dinesh Shenoy ◽  
Jane Li ◽  
Curtis Crasto ◽  
Graham Jones ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Ethylene Glycol ◽  
Biomedical Applications ◽  
Functional Group ◽  
Thiol Group ◽  
Poly Ethylene Glycol ◽  
Surface Attachment ◽  
Quenching Effect ◽  
Reactive Functional Group ◽  
Poly Ethylene

ABSTRACTTo increase the targeting potential, circulation time, and the flexibility of surface-attached biomedically-relevant ligands on gold nanoparticles, hetero-bifunctional poly(ethylene glycol) (PEG, MW 1, 500) was synthesized having a thiol group on one terminus and a reactive functional group on the other. Coumarin, a model fluorescent dye, was conjugated to the PEG spacer and gold nanoparticles were modified with coumarin-PEG-thiol. Surface attachment of coumarin through the PEG spacer decreases the fluorescence quenching effect of gold nanoparticles. The results of cellular cytotoxicity and fluorescence confocal analyses showed that the PEG spacer modified nanoparticles were essentially non-toxic and could be efficiently internalized in the cells within one hour of incubation.

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