scholarly journals Direct Cross-Coupling of Alcohols with O-Nucleophiles Mediated by N-Iodosuccinimide as a Precatalyst under Mild Reaction Conditions

Catalysts ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 858
Author(s):  
Njomza Ajvazi ◽  
Stojan Stavber
Keyword(s):  
Substrate Concentration ◽  
Cross Coupling ◽  
High Substrate Concentration ◽  
Reaction Conditions ◽  
One Pot ◽  
High Substrate ◽  
Direct Cross ◽  
Chemical Profiles ◽  
Alkylation Reactions

We report N-iodosuccinimide as the most efficient and selective precatalyst among the N-halosuccinimides for dehydrative O-alkylation reactions between various alcohols under high-substrate concentration reaction conditions. The protocol is non-metal, one-pot, selective, and easily scalable, with excellent yields; enhancing the green chemical profiles of these transformations.

scholarly journals N-Halosuccinimides as Precatalysts for C-, N-, O-, and X-Nucleophilic Substitution Reactions of Alcohols under Mild Reaction Conditions

Catalysts ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 460
Author(s):  
Njomza Ajvazi ◽  
Stojan Stavber
Keyword(s):  
Nucleophilic Substitution ◽  
Substrate Concentration ◽  
Solvent Free ◽  
Substitution Reactions ◽  
High Substrate Concentration ◽  
Reaction Conditions ◽  
High Substrate ◽  
Nucleophilic Substitution Reactions ◽  
Solvent Free Reaction

N-halosuccinimides (chloro, bromo, and iodo, respectively) were introduced, tested, and applied as efficient and non-metal precatalysts for C-, N-, O-, and X-nucleophilic substitution reactions of alcohols under solvent-free reaction conditions (SFRC) or under high substrate concentration reaction conditions (HCRC) efficiently and selectively, into the corresponding products.

Enhanced thermostability and tolerance of high substrate concentration of an esterase by directed evolution

2004 ◽  
Vol 27 (4-6) ◽  
pp. 169-175 ◽  
Author(s):  
Ji-Heui Kim ◽  
Gi-Sub Choi ◽  
Seung-Bum Kim ◽  
Won-Ho Kim ◽  
Jin-Young Lee ◽  
...  
Keyword(s):  
Directed Evolution ◽  
Substrate Concentration ◽  
High Substrate Concentration ◽  
High Substrate

scholarly journals Synthesis and oxidation of aminoalkyl-onium compounds by pig kidney diamine oxidase

1971 ◽  
Vol 122 (4) ◽  
pp. 557-567 ◽  
Author(s):  
W. G. Bardsley ◽  
J. S. Ashford ◽  
C. M. Hill
Keyword(s):  
Substrate Concentration ◽  
Diamine Oxidase ◽  
Amino Group ◽  
High Substrate Concentration ◽  
High Substrate ◽  
Pig Kidney ◽  
Substrate Interaction ◽  
Enzyme Substrate ◽  
Potent Inhibition

1. The preparation of a series of compounds derived from diamines by replacing one amino group by a dimethylsulphonium, isothiuronium, trimethylammonium, NN′-dimethylimidazolium or N-methylpyridinium species is described. 2. The behaviour of these compounds as substrates of pig kidney diamine oxidase is reported. All but the trimethylammonium compounds proved to be substrates. 3. Many of these compounds showed potent inhibition at high substrate concentration and this was studied. 4. On the basis of these and other observations a scheme for enzyme–substrate interaction is suggested.

scholarly journals Effect of Substrate Feeding Concentration on Initial Biofilm Development in Anaerobic Hybrid Reactor

2017 ◽  
Vol 20 (3&4) ◽  
pp. 361-372
Author(s):  
B. Suraraksa ◽  
A. Nopharatana ◽  
P. Chaiprasert ◽  
S. Bhumiratana ◽  
M. Tanticharoen
Keyword(s):  
High Glucose ◽  
Glucose Concentration ◽  
Substrate Concentration ◽  
Early Stage ◽  
Hybrid Reactor ◽  
High Glucose Concentration ◽  
High Substrate Concentration ◽  
High Substrate ◽  
Low Glucose ◽  
Biofilm Development

To elucidate the effect of substrate concentration on biofilm development, glucose concentrations of 500 and 1,000 mg/L were used.  At an early stage, biofilm development at both concentrations was not significantly different (P=0.621).  After removing suspended biomass at 24 operational hours, the biofilm development at high substrate concentration was higher than at lower concentration.  At 72 operational hours, the amounts of attached biomass at low and high glucose feeding were 9.04±1.17 and 28.58±2.72 g VSS/m2, respectively.  The activities of acidogens, acetogens, and methanogens at the low glucose concentration were 0.334, 0.016 and 0.003 g COD/g VSS/h, and those at the high glucose concentration were 0.145, 0.003 and 0.001 g COD/g VSS/h, respectively.  Moreover, the ratio of methanogenic activity at low glucose concentration was higher than at high glucose concentration.  The glucose utilization at low and high feeding concentrations was 33% and 27%, respectively.  These results indicated that rapid biofilm development by using high substrate concentration would be less beneficial if unbalance of methanogenic ratio was found in biofilm.

scholarly journals Using Choline Chloride-Based DESs as Co-Solvent for 3,5-Bis(trifluoromethyl) Acetophenone Bioreduction with Rhodococcus erythropolis XS1012

Catalysts ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 30 ◽  
Author(s):  
Chen ◽  
Qian ◽  
Lin ◽  
Chen ◽  
Wang
Keyword(s):  
Substrate Concentration ◽  
Choline Chloride ◽  
Cell Activity ◽  
Great Influence ◽  
Rhodococcus Erythropolis ◽  
Deep Eutectic Solvents ◽  
Cell Membrane Permeability ◽  
Buffer System ◽  
High Substrate Concentration ◽  
Reaction Conditions

(S)-3,5-Bistrifluoromethylphenyl ethanol((S)-BTPE) is a key pharmaceutical intermediate of the NK-1 receptor antagonist. The asymmetric bioreduction of 3,5-bis(trifluoromethyl) acetophenone (BTAP) to (S)-BTPE using Rhodococcus erythropolis XS1012 has been established in a phosphate buffer system. To overcome the problem of unsatisfactory yields at high substrate concentration, deep eutectic solvents (DESs) have been introduced to the buffer system. After screening 13 kinds of choline chloride-based DESs, [choline chloride][urea] ([ChCl][U]) showed great influence on the cell activity and significantly increased the cell membrane permeability. Subsequently, some major parameters for this reaction were determined. A remarkable (S)-BTPE yield of 91.9% was gained at 150 mM substrate concentration under optimized reaction conditions with >99.9% product enantioselectivity. Compared to reduction in a buffer system, the developed [ChCl][U]-containing system increased the yield from 82.6% to 91.9%. It maintains a yield of 80.7% with the substrate concentration up to 300 mM, compared to only 63.0% in buffer system. This study demonstrated that [ChCl][U] is a feasible co-solvent to improve the bioreduction process.

Consecutive Palladium Catalyzed Reactions in One-Pot Reactions

2020 ◽  
Vol 17 (5) ◽  
pp. 559-569
Author(s):  
Ingrid Caroline Vaaland ◽  
Magne Olav Sydnes
Keyword(s):  
Cross Coupling ◽  
Coupling Reactions ◽  
Homogeneous Reaction ◽  
Reaction Conditions ◽  
One Pot ◽  
Cross Coupling Reactions ◽  
Palladium Catalyzed ◽  
Catalyzed Reactions

Combining palladium catalyzed reactions in one-pot reactions represents an efficient and economical use of catalyst. The Suzuki-Miyaura cross-coupling has been proven to be a reaction which can be combined with other palladium catalyzed reactions in the same pot. This mini-review will highlight some of the latest examples where Suzuki-Miyaura cross-coupling reactions have been combined with other palladium catalyzed reactions in one-pot reaction. Predominantly, examples with homogeneous reaction conditions will be discussed in addition to a few examples from the authors where Pd/C have been used as a catalyst.

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