Mechanisms and Substituent Effects of Metal-Free Bioorthogonal Reactions

2021 ◽  
Author(s):  
Titas Deb ◽  
Julian Tu ◽  
Raphael M. Franzini
Keyword(s):  
Substituent Effects ◽  
Bioorthogonal Reactions ◽  
Metal Free

scholarly journals Metal-Free Synthetic Approach to 3-Monosubstituted Unsymmetrical 1,2,4,5-Tetrazines Useful for Bioorthogonal Reactions

2018 ◽  
Vol 130 (37) ◽  
pp. 12233-12237 ◽  
Author(s):  
Yangyang Qu ◽  
François-Xavier Sauvage ◽  
Gilles Clavier ◽  
Fabien Miomandre ◽  
Pierre Audebert
Keyword(s):  
Synthetic Approach ◽  
Bioorthogonal Reactions ◽  
Metal Free

Tuning the maximum absorption wavelengths of phthalocyanine derivatives

2005 ◽  
Vol 09 (01) ◽  
pp. 32-39 ◽  
Author(s):  
Shan Jin ◽  
Gongzhen Cheng ◽  
George Z. Chen ◽  
Zhenping Ji
Keyword(s):  
General Formula ◽  
Absorption Spectra ◽  
Electronic Absorption ◽  
Electronic Absorption Spectra ◽  
Substituent Effects ◽  
Maldi Tof Ms ◽  
Metal Free ◽  
Maldi Tof ◽  
Low Symmetry ◽  
Tof Ms

A new series of low-symmetry octasubstituted metal-free phthalocyanines with the general formula H 2 N x P β4− x ( OBu )8 ( x = 0-4) were synthesized by mixed condensation of two different substituted precursors (4,5-dibutoxy- phthalonitrile and 1,4-dibutoxy-2,3-dicyanonaphthalene). Their electronic absorption spectra and MALDI-TOF-MS were investigated. The regiospecific, nonlinear and linear substituent effects of alkoxyl groups on the positions of the Q-bands of phthalocyanines with different substituent groups at different peripheral positions were systematically investigated. The results could provide a guide to the tuning of Q-band absorptions of phthalocyanine derivatives.

scholarly journals Metal-Free Synthetic Approach to 3-Monosubstituted Unsymmetrical 1,2,4,5-Tetrazines Useful for Bioorthogonal Reactions

2018 ◽  
Vol 57 (37) ◽  
pp. 12057-12061 ◽  
Author(s):  
Yangyang Qu ◽  
François-Xavier Sauvage ◽  
Gilles Clavier ◽  
Fabien Miomandre ◽  
Pierre Audebert
Keyword(s):  
Synthetic Approach ◽  
Bioorthogonal Reactions ◽  
Metal Free

Substituent Effects of 2-Pyridones on Selective O-Arylation with Diaryliodonium Salts: Synthesis of 2-Aryloxypyridines under Transition­-Metal-Free Conditions

Synthesis ◽  
2018 ◽  
Vol 50 (08) ◽  
pp. 1699-1710 ◽  
Author(s):  
Dong-Liang Mo ◽  
Xiao-Hua Li ◽  
Ai-Hui Ye ◽  
Cui Liang
Keyword(s):  
Transition Metal ◽  
Functional Groups ◽  
Steric Hindrance ◽  
Good Yield ◽  
Substituent Effects ◽  
Lead Compound ◽  
Metal Free ◽  
Diaryliodonium Salts ◽  
Good Precursor

An efficient transition-metal-free strategy to synthesize 2-aryloxypyridine derivatives has been developed by a selective O-arylation of 2-pyridones with diaryliodonium salts. The reaction was compatible with a series of functional groups for 2-pyridones and diaryliodonium salts such as halides, nitro, cyano, and ester groups. The substituents at the C6-position of 2-pyridones favored O-arylation products because of steric hindrance. The reaction was easily performed on a gram-scale and 6-chloro-2-pyridone was a good precursor to access various unsubstituted 2-aryloxypyridines by dehalogenation. A P2Y1 lead compound analogue could be prepared in good yield over two steps.

The Shadow Widths of Very Small Particles are Formed Independently of the Metal Cap Build Up on the Particle

1981 ◽  
Vol 39 ◽  
pp. 568-569
Author(s):  
George C. Ruben
Keyword(s):  
Gold Particle ◽  
Film Surface ◽  
Small Particles ◽  
Geometric Process ◽  
Metal Free ◽  
Shadow Area

The formation of shadows behind small particles has been thought to be a geometric process (GP) where the metal cap build up on the particle creates a shadow width the same size as or larger than the particle. This GP cannot explain why gold particle shadow widths are generally larger than the gold particle and may have no appreciable metal cap build up (fig. 1). Ruben and Telford have suggested that particle shadow widths are formed by the width dependent deflection of shadow metal (SM) lateral to and infront of the particle. The trajectory of the deflected SM is determined by the incoming shadow angle (45°). Since there can be up to 1.4 times (at 45°) more SM directly striking the particle than the film surface, a ridge of metal nuclei lateral to and infront of the particle can be formed. This ridge in turn can prevent some SM from directly landing in the metal free shadow area. However, the SM that does land in the shadow area (not blocked by the particle or its ridge) does not stick and apparently surface migrates into the SM film behind the particle.

Recent advancement in the electrocatalytic synthesis of ammonia

Nanoscale ◽  
2020 ◽  
Vol 12 (15) ◽  
pp. 8065-8094 ◽  
Author(s):  
Xudong Wen ◽  
Jingqi Guan
Keyword(s):  
Metal Oxide ◽  
Oxide Catalysts ◽  
Single Atom ◽  
Metal Oxide Catalysts ◽  
Metal Free ◽  
Recent Advancement ◽  
Nanocomposite Catalysts

Different kinds of electrocatalysts used in NRR electrocatalysis (including single atom catalysts, metal oxide catalysts, nanocomposite catalysts, and metal free catalysts) are introduced.

Transition-metal-free catalytic hydroboration reduction of amides to amines

2020 ◽  
Vol 7 (21) ◽  
pp. 3515-3520
Author(s):  
Wubing Yao ◽  
Jiali Wang ◽  
Aiguo Zhong ◽  
Shiliang Wang ◽  
Yinlin Shao
Keyword(s):  
Transition Metal ◽  
Selective Catalytic Reduction ◽  
Catalytic Reduction ◽  
Value Added ◽  
Metal Free

The selective catalytic reduction of amides to value-added amine products is a desirable but challenging transformation.

Deaminative carbonylative thioesterification of activated alkylamines with thiophenols under transition-metal-free conditions

2021 ◽  
Author(s):  
Fengqian Zhao ◽  
Xiao-Feng Wu
Keyword(s):  
Free Radical ◽  
Transition Metal ◽  
Metal Free

A transition-metal-free radical carbonylation of activated alkylamines with thiophenols has been successfully developed. Various thioesters were selectively produced with moderate to good yields.

Substituent effects and solvents

1992 ◽  
Vol 89 ◽  
pp. 1567-1571
Author(s):  
O Pytela ◽  
M Ludwig
Keyword(s):  
Substituent Effects

Stereodivergent Alkyne Hydrofluorination Using a Simple Practical Reagent

2020 ◽  
Author(s):  
Rui Guo ◽  
Xiaotian Qi ◽  
Hengye Xiang ◽  
Paul Geaneoates ◽  
Ruihan Wang ◽  
...  
Keyword(s):  
Bond Formation ◽  
Biologically Active ◽  
Dft Studies ◽  
Thermodynamic Control ◽  
Important Goal ◽  
Peptide Bonds ◽  
Metal Free ◽  
Vinyl Cation ◽  
E And Z Isomers ◽  
Vinyl Fluorides

Vinyl fluorides play an important role in drug development as they serve as bioisosteres for peptide bonds and are found in a range of biologically active molecules. The discovery of safe, general and practical procedures to prepare vinyl fluorides remains an important goal and challenge for synthetic chemistry. Here we introduce an inexpensive and easily-handled reagent and report simple, scalable, and metal-free protocols for the regioselective and stereodivergent hydrofluorination of alkynes to access both the E and Z isomers of vinyl fluorides. These conditions were suitable for a diverse collection of alkynes, including several highly-functionalized pharmaceutical derivatives. Mechanistic and DFT studies support C–F bond formation through a vinyl cation intermediate, with the (E)- and (Z)-hydrofluorination products forming under kinetic and thermodynamic control, respectively.<br>

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