Glycosyl Triazole Ligand for Temperature-Dependent Competitive Reactions of Cu-Catalyzed Sonogashira Coupling and Glaser Coupling

2021 ◽  
Author(s):  
Nidhi Mishra ◽  
Sumit K. Singh ◽  
Anoop S. Singh ◽  
Anand K. Agrahari ◽  
Vinod K. Tiwari
Keyword(s):  
Sonogashira Coupling ◽  
Temperature Dependent ◽  
Competitive Reactions ◽  
Triazole Ligand ◽  
Glaser Coupling

scholarly journals A partially fluorinated ligand for two super-hydrophobic porous coordination polymers with classic structures and increased porosities

2020 ◽  
Author(s):  
Chao Wang ◽  
Dong-Dong Zhou ◽  
You-Wei Gan ◽  
Xue-Wen Zhang ◽  
Zi-Ming Ye ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Coordination Polymers ◽  
Surface Characteristic ◽  
Contact Angles ◽  
Porous Coordination Polymers ◽  
Temperature Dependent ◽  
One Pot ◽  
Water Contact ◽  
Triazole Ligand ◽  
Trifluoromethyl Groups

Abstract 3-Ethyl-5-trifluoromethyl-1,2,4-triazole is synthesized by a one-pot reaction. Using this asymmetric triazole ligand bearing one trifluoromethyl and one ethyl as side groups, we construct two new porous coordination polymers, MAF-9 and MAF-2F, being isostructural with the classic hydrophobic and flexible materials, FMOF-1 and MAF-2, based on symmetric triazole ligands bearing two trifluoromethyl groups or two ethyl groups, respectively. MAF-9 and MAF-2F can adsorb large amounts of organic solvents but completely exclude water, showing superhydrophobicity with water contact angles of 152o in between those of FMOF-1 and MAF-2. MAF-9 exhibits very large N2-induced breathing and colossal positive and negative thermal expansions like FMOF-1, but the lower molecular weight and smaller volume of MAF-9 give 16% and 4% higher gravimetric and volumetric N2 uptakes, respectively. In contrast, MAF-2F is quite rigid and does not show the inversed temperature-dependent N2 adsorption and large guest-induced expansion like MAF-2. Further, despite the higher molecular weight and larger volume, MAF-2F possesses 6% and 25% higher gravimetric and volumetric CO2 uptakes, respectively. These results can be explained by the different pore sizes and side group arrangements in the two classic framework prototypes, which demonstrate the delicate roles of ligand side groups in controlling porosity, surface characteristic and flexibility.

scholarly journals Linear free-energy correlation analysis of the electronic effects of the substituents in the Sonogashira coupling reaction

2008 ◽  
Vol 86 (5) ◽  
pp. 410-415 ◽  
Author(s):  
Christine Gottardo ◽  
Thomas M Kraft ◽  
M Selim Hossain ◽  
Peter V Zawada ◽  
Heidi M Muchall
Keyword(s):  
Correlation Analysis ◽  
Relative Rate ◽  
Coupling Reaction ◽  
Sonogashira Reaction ◽  
Sonogashira Coupling ◽  
Electronic Effects ◽  
Linear Free Energy ◽  
Competitive Reactions ◽  
Sonogashira Coupling Reaction ◽  
Hammett Correlation

Relative rate constants (krel) for the Sonogashira coupling were determined in competitive reactions between iodobenzene and a series of para- and meta-substituted iodobenzenes and compared to the charge on iodine and the z-component of the quadrupole moment of the iodine-bearing carbon. We use an Hammett correlation analysis and the computational data to provide further evidence that the rate limiting step of the Sonogashira reaction is the initial oxidative addition of Pd to the carbon-iodine bond.Key words: Sonogashira, competitive reactions, Hammett correlation.

scholarly journals The effects of amines on oxidative homo-coupling of terminal alkynes promoted by copper salts

2005 ◽  
Vol 2005 (2) ◽  
pp. 112-115 ◽  
Author(s):  
Lei Wang ◽  
Jincan Yan ◽  
Pinhua Li ◽  
Min Wang ◽  
Caina Su
Keyword(s):  
Reaction Medium ◽  
Cross Coupling ◽  
Catalytic Amount ◽  
Sonogashira Reaction ◽  
Coupling Reactions ◽  
Sonogashira Coupling ◽  
Terminal Alkynes ◽  
Copper Salts ◽  
Terminal Acetylenes ◽  
Glaser Coupling

The effects of all kinds of amines on homo-couplings (Glaser reactions) of terminal alkynes promoted by copper salts and the Sonogashira coupling reactions were studied systematically. Diethylamine (2° amine) can serve as an excellent solvent, base and coordination ligand in the oxidative homo-coupling of terminal alkynes and several modified Glaser coupling procedures have been developed which are based on a catalytic amount of cuprous salts (CuI, CuBr or CuCl) with diethylamine systems. Homo-coupling of terminal acetylenes in the Sonogashira reaction could be inhibited by using triethylamine (3° amine) as reaction medium, and the cross-coupling products were formed as the exclusive products.

(111) Monocrystalline Nickel Films

1972 ◽  
Vol 30 ◽  
pp. 512-513
Author(s):  
T.E. Pratt ◽  
R.W. Vook
Keyword(s):  
Film Thickness ◽  
Deposition Rate ◽  
Room Temperature ◽  
Narrow Range ◽  
High Vacuum ◽  
Residual Pressure ◽  
Temperature Dependent ◽  
Deposition Parameters ◽  
Transmission Electron ◽  
Substrate Temperatures

(111) oriented thin monocrystalline Ni films have been prepared by vacuum evaporation and examined by transmission electron microscopy and electron diffraction. In high vacuum, at room temperature, a layer of NaCl was first evaporated onto a freshly air-cleaved muscovite substrate clamped to a copper block with attached heater and thermocouple. Then, at various substrate temperatures, with other parameters held within a narrow range, Ni was evaporated from a tungsten filament. It had been shown previously that similar procedures would yield monocrystalline films of CU, Ag, and Au.For the films examined with respect to temperature dependent effects, typical deposition parameters were: Ni film thickness, 500-800 A; Ni deposition rate, 10 A/sec.; residual pressure, 10-6 torr; NaCl film thickness, 250 A; and NaCl deposition rate, 10 A/sec. Some additional evaporations involved higher deposition rates and lower film thicknesses.Monocrystalline films were obtained with substrate temperatures above 500° C. Below 450° C, the films were polycrystalline with a strong (111) preferred orientation.

In Vitro Effects of Urokinase — Prevention by Different Inhibitors

1990 ◽  
Vol 64 (03) ◽  
pp. 402-406 ◽  
Author(s):  
M D Oethinger ◽  
E Seifried
Keyword(s):  
In Vitro Study ◽  
Thrombin Time ◽  
Plasma Samples ◽  
Temperature Dependent ◽  
Chloromethyl Ketone ◽  
Control Value ◽  
Dose Time ◽  
In Vitro Effects ◽  
Full Protection

SummaryThe present in vitro study investigated dose-, time- and temperature-dependent effects of two-chain urokinase plasminogen activato(u-PA, urokinase) on normal citrated plasma. When 10 μg/ml u-PA wereadded to pooled normal plasma and incubated for 30 min at an ambient temperature (25° C), α2-antiplas-min decreased to 8% of the control value. Incubation on ice yielded a decrease to 45% of control,whereas α2-antiplasmin was fully consumed at 37° C. Fibrinogen and plasminogen fell to 46% and 39%, respectively, after a 30 min incubation at 25° C. Thrombin time prolonged to 190% of control.Various inhibitors were studied with respect to their suitability and efficacy to prevent these in vitro effects. Aprotinin exhibited a good protective effect on fibrinogen at concentrations exceeding 500 KlU/ml plasma. Its use, however, was limited due to interferences with some haemostatic assays. We could demonstrate that L-Glutamyl-L-Glycyl-L-Arginyl chloromethyl ketone (GGACK) and a specific polyclonal anti-u-PA-antibody (anti-u-PA-IgG) effectively inhibited urokinase-induced plasmin generation without interfering with haemostatic assays. The anti-u-PA-antibody afforded full protection ofα2-antiplasmin at therapeutic levels of u-PA.It is concluded that u-PA in plasma samples from patients during thrombolytic therapy may induce in vitro effects which should be prevented by the use of a suitable inhibitor such as GGACK or specific anti-u-PA-antibody.

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