scholarly journals Earthworms as a Biocatalyst: In Asymmetric Aldol Reactions

2017 ◽  
Vol 22 (9) ◽  
pp. 1162-1167
Author(s):  
Guo-Yan Zhang ◽  
Yan-Li Chen ◽  
Hai-Hong Li ◽  
Zhi Guan ◽  
Yan-Hong He
Keyword(s):  
Crude Extract ◽  
Industrial Production ◽  
Carbonyl Compounds ◽  
Large Scale ◽  
Environmentally Friendly ◽  
Aldol Reactions ◽  
Asymmetric Aldol ◽  
Excellent Yield ◽  
Wide Range ◽  
Potential Possibility

A crude extract from earthworms was used as an environmentally friendly and easily accessible biocatalyst for asymmetric direct aldol reactions. The β-hydroxy carbonyl compounds could be prepared in yields of up to 94%, with ee values of up to 98% and dr of up to >99:1. A wide range of substrates could participate in the reaction. This earthworm catalyst was also efficient in the large-scale reaction, providing product in excellent yield and good selectivity. The protocol as an example gives inspiration for the development of sustainable catalysts from nature, which also provides a potential possibility for application of earthworm catalyst in industrial production.

Catalytic asymmetric aldol addition reactions of 3-fluoro-indolinone derived enolates

2017 ◽  
Vol 15 (2) ◽  
pp. 311-315 ◽  
Author(s):  
Lijun Zhang ◽  
Wenzhong Zhang ◽  
Haibo Mei ◽  
Jianlin Han ◽  
Vadim A. Soloshonok ◽  
...  
Keyword(s):  
Aldol Reactions ◽  
Addition Reactions ◽  
Asymmetric Aldol ◽  
Wide Range ◽  
Stereogenic Centers ◽  
New Type ◽  
Catalytic Asymmetric ◽  
Aldol Addition ◽  
Quaternary Stereogenic Centers

Cu(i)/bisoxazoline ligand catalyzed asymmetric aldol reactions of fluoro-indolinone derived new type tertiary enolates have been developed. This process allows the preparation of a wide range of α-fluoro-β-aryl/hetaryl/alkyl-β-hydroxy-indolin-2-one products containing C–F quaternary stereogenic centers.

Direct Asymmetric Aldol Reactions Catalyzed by Lipase from Porcine Pancreas

2014 ◽  
Vol 69 (3-4) ◽  
pp. 170-180 ◽  
Author(s):  
Jing Zheng ◽  
Bang-Hua Xie ◽  
Yan-Li Chen ◽  
Jian-Fei Cao ◽  
Yang Yang ◽  
...  
Keyword(s):  
Organic Synthesis ◽  
Aldol Reactions ◽  
Type Ii ◽  
Cyclic Ketones ◽  
Porcine Pancreas ◽  
Asymmetric Aldol ◽  
Porcine Pancreas Lipase ◽  
Wide Range ◽  
Valuable Method ◽  
High Yields

Porcine pancreas lipase type II (PPL II) exhibited unnatural catalytic activity in direct asymmetric aldol reactions between cyclic ketones and aromatic or heteroaromatic aldehydes in acetonitrile in the presence of phosphate buffer. A wide range of substrates was accepted by the enzyme to afford the corresponding aldol products in low to high yields (10 - 98%), with moderate to excellent enantioselectivities (53 - 94% ee, for anti-isomers) and low to moderate diastereoselectivities (48/52 - 87/13 dr, anti/syn). This methodology expands the application of PPL II, and it might be developed into a potentially valuable method for sustainable organic synthesis.

Efficient synthesis of zirconium poly(styrene-phenylvinylphosphonate)phosphate-supported proline as a recyclable catalyst for direct asymmetric aldol reactions in water

RSC Advances ◽  
2015 ◽  
Vol 5 (5) ◽  
pp. 3168-3176 ◽  
Author(s):  
Chuanlong Wu ◽  
Xiaoqin Long ◽  
Xiangkai Fu ◽  
Guangwei Wang ◽  
Zakaria. A. Mirza
Keyword(s):  
Large Scale ◽  
Recyclable Catalyst ◽  
Aldol Reactions ◽  
Efficient Synthesis ◽  
Asymmetric Aldol

A completely non-chromatographic and highly large-scale adaptable synthesis of zirconium poly(styrene-phenylvinylphosphonate)phosphate-supported l-proline (ZrPS-PVPA-Pr) has been developed in only three steps overall.

ChemInform Abstract: The Application of a Structurally Simple, Recyclable, and Large-Scale L-Prolinamide Catalyst for Asymmetric Aldol Reactions.

ChemInform ◽  
2014 ◽  
Vol 45 (51) ◽  
pp. no-no
Author(s):  
Zhi Guan ◽  
Yuan Luo ◽  
Bao-Qiang Zhang ◽  
Krystal Heinen ◽  
Da-Cheng Yang ◽  
...  
Keyword(s):  
Large Scale ◽  
Aldol Reactions ◽  
Asymmetric Aldol

The application of a structurally simple, recyclable, and large-scale l-prolinamide catalyst for asymmetric aldol reactions

2014 ◽  
Vol 25 (10-11) ◽  
pp. 802-812 ◽  
Author(s):  
Zhi Guan ◽  
Yuan Luo ◽  
Bao-Qiang Zhang ◽  
Krystal Heinen ◽  
Da-Cheng Yang ◽  
...  
Keyword(s):  
Large Scale ◽  
Aldol Reactions ◽  
Asymmetric Aldol

Electron microscopy study of reactively sputter-deposited Ti/N films on silicon

1992 ◽  
Vol 50 (2) ◽  
pp. 1362-1363
Author(s):  
V. C. Kannan ◽  
A. K. Singh ◽  
R. B. Irwin ◽  
S. Chittipeddi ◽  
F. D. Nkansah ◽  
...  
Keyword(s):  
Integrated Circuits ◽  
Large Scale ◽  
Hexagonal Phase ◽  
Microscopy Study ◽  
Electron Microscopy Study ◽  
Process Conditions ◽  
Tin Films ◽  
Wide Range ◽  
Fcc Phase ◽  
Circuits Vlsi

Titanium nitride (TiN) films have historically been used as diffusion barrier between silicon and aluminum, as an adhesion layer for tungsten deposition and as an interconnect material etc. Recently, the role of TiN films as contact barriers in very large scale silicon integrated circuits (VLSI) has been extensively studied. TiN films have resistivities on the order of 20μ Ω-cm which is much lower than that of titanium (nearly 66μ Ω-cm). Deposited TiN films show resistivities which vary from 20 to 100μ Ω-cm depending upon the type of deposition and process conditions. TiNx is known to have a NaCl type crystal structure for a wide range of compositions. Change in color from metallic luster to gold reflects the stabilization of the TiNx (FCC) phase over the close packed Ti(N) hexagonal phase. It was found that TiN (1:1) ideal composition with the FCC (NaCl-type) structure gives the best electrical property.

THE SOME QUESTIONS OF AUTONOMOUS MOTION AND MANAGEMENT OF LAND-MOBILE ROBOTIC COMPLEXES FOR UKRAINIAN GROUND FORCESE

2019 ◽  
pp. 53-58
Author(s):  
О. Кravchuk ◽  
V. Symonenkov ◽  
I. Symonenkova ◽  
O. Hryhorev
Keyword(s):  
Large Scale ◽  
Armed Forces ◽  
Distributed Information ◽  
Wide Range ◽  
Highly Effective ◽  
Information Management Systems ◽  
Robotic Devices ◽  
Principles And Standards ◽  
And Control ◽  
The Eu

Today, more than forty countries of the world are engaged in the development of military-purpose robots. A number of unique mobile robots with a wide range of capabilities are already being used by combat and intelligence units of the Armed forces of the developed world countries to conduct battlefield intelligence and support tactical groups. At present, the issue of using the latest information technology in the field of military robotics is thoroughly investigated, and the creation of highly effective information management systems in the land-mobile robotic complexes has acquired a new phase associated with the use of distributed information and sensory systems and consists in the transition from application of separate sensors and devices to the construction of modular information subsystems, which provide the availability of various data sources and complex methods of information processing. The purpose of the article is to investigate the ways to increase the autonomy of the land-mobile robotic complexes using in a non-deterministic conditions of modern combat. Relevance of researches is connected with the necessity of creation of highly effective information and control systems in the perspective robotic means for the needs of Land Forces of Ukraine. The development of the Armed Forces of Ukraine management system based on the criteria adopted by the EU and NATO member states is one of the main directions of increasing the effectiveness of the use of forces (forces), which involves achieving the principles and standards necessary for Ukraine to become a member of the EU and NATO. The inherent features of achieving these criteria will be the transition to a reduction of tasks of the combined-arms units and the large-scale use of high-precision weapons and land remote-controlled robotic devices. According to the views of the leading specialists in the field of robotics, the automation of information subsystems and components of the land-mobile robotic complexes can increase safety, reliability, error-tolerance and the effectiveness of the use of robotic means by standardizing the necessary actions with minimal human intervention, that is, a significant increase in the autonomy of the land-mobile robotic complexes for the needs of Land Forces of Ukraine.

Stirring and aeration system for the upgrading of small waste water treatment plants

1994 ◽  
Vol 29 (12) ◽  
pp. 149-156 ◽  
Author(s):  
Marcus Höfken ◽  
Katharina Zähringer ◽  
Franz Bischof
Keyword(s):  
Waste Water ◽  
Water Treatment ◽  
Large Scale ◽  
Waste Water Treatment ◽  
Water Treatment Plants ◽  
Waste Water Treatment Plants ◽  
Basic Fluid ◽  
Aeration System ◽  
Technical Realization ◽  
Wide Range

A novel agitating system has been developed which allows for individual or combined operation of stirring and aeration processes. Basic fluid mechanical considerations led to the innovative hyperboloid design of the stirrer body, which ensures high efficiencies in the stirring and the aeration mode, gentle circulation with low shear forces, excellent controllability, and a wide range of applications. This paper presents the basic considerations which led to the operating principle, the technical realization of the system and experimental results in a large-scale plant. The characteristics of the system and the differences to other stirring and aeration systems are illustrated. Details of the technical realization are shown, which conform to the specific demands of applications in the biological treatment of waste water. Special regard is given to applications in the upgrading of small compact waste water treatment plants.

Thin structure of heterogeneous and multiphase fluid flows

2012 ◽  
Vol 9 (1) ◽  
pp. 175-180
Author(s):  
Yu.D. Chashechkin
Keyword(s):  
Large Scale ◽  
Fundamental System ◽  
Fluid Flows ◽  
Regular Solutions ◽  
Flow Models ◽  
Group Methods ◽  
Wide Range ◽  
Thin Structure ◽  
Multiphase Fluid ◽  
Complete Solutions

According to the results of visualization of streams, the existence of structures in a wide range of scales is noted: from galactic to micron. The use of a fundamental system of equations is substantiated based on the results of comparing symmetries of various flow models with the usage of theoretical group methods. Complete solutions of the system are found by the methods of the singular perturbations theory with a condition of compatibility, which determines the characteristic equation. A comparison of complete solutions with experimental data shows that regular solutions characterize large-scale components of the flow, a rich family of singular solutions describes formation of the thin media structure. Examples of calculations and observations of stratified, rotating and multiphase media are given. The requirements for the technique of an adequate experiment are discussed.

α-Alkoxyalkyl Triphenylphosphonium Salts: Synthesis and Reactions

2019 ◽  
Vol 23 (16) ◽  
pp. 1738-1755
Author(s):  
Humaira Y. Gondal ◽  
Zain M. Cheema ◽  
Abdul R. Raza ◽  
Ahmed Abbaskhan ◽  
M. I. Chaudhary
Keyword(s):  
Carbonyl Compounds ◽  
Claisen Rearrangement ◽  
Alder Reaction ◽  
Coupling Reactions ◽  
Phosphonium Salts ◽  
Organic Transformations ◽  
Enol Ethers ◽  
Wide Range ◽  
Synthetic Methodologies ◽  
Alkoxy Groups

Following numerous applications of Wittig reaction now functionalized phosphonium salts are gaining attention due to their characteristic properties and diverse reactivity. This review is focused on α-alkoxyalkyl triphenylphosphonium salts: an important class of functionalized phosphonium salts. Alkoxymethyltriphenylphosphonium salts are majorly employed in the carbon homologation of carbonyl compounds and preparation of enol ethers. Their methylene insertion strategy is extensively demonstrated in the total synthesis of a wide range of natural products and other important organic molecules. Similarly enol ethers prepared thereof are important precursors for different organic transformations like Diels-Alder reaction, Claisen rearrangement, Coupling reactions, Olefin metathesis and Nazarov cyclization. Reactivity of these α-alkoxyalkylphosphonium salts have also been studied in the nucleophilic substitution reactions. A distinctive application of this class of phosphonium salts was recently reported in the phenylation of carbonyl compounds under very mild conditions. Synthesis of structurally diverse alkoxymethyltriphenylphosphonium salts with variation in alkoxy groups as well as counter anions are reported in literature. Here we present a detailed account of different synthetic methodologies for the preparation of this unique class of quaternary phosphonium salts and their applications in organic synthesis.

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