scholarly journals Microwave-Assisted Heating Reactions of N-Acetylglucosamine (GlcNAc) in Sulfolane as a Method Generating 1,6-Anhydrosugars Consisting of Amino Monosaccharide Backbones

Molecules ◽  
2020 ◽  
Vol 25 (8) ◽  
pp. 1944
Author(s):  
Harumi Kaga ◽  
Masaru Enomoto ◽  
Hiroki Shimizu ◽  
Izuru Nagashima ◽  
Keigo Matsuda ◽  
...  
Keyword(s):  
Optimal Condition ◽  
General Feature ◽  
Time Course ◽  
High Efficiency ◽  
Raw Materials ◽  
Reaction Conditions ◽  
Microwave Assisted ◽  
High Potentials ◽  
Course Changes

The microwave-assisted heating reaction of N-acetyl glucosamine (GlcNAc) in sulfolane is described. The reaction produces two major products that are assignable to 1,6-anhydro-2-acetamido-2-deoxy-β-d-glucopyranose (AGPNAc) and 1,6-anhydro-2-acetamido-2-deoxy-β-d-glucofuranose (AGFNAc). In order to reveal a general feature of the system, the 3, 5, and 10 min reactions were performed at 140, 160, 180, 200, and 220 °C to clarify the time course changes in the conversion of GlcNAc and the yields of the two produced 1,6-anhydrosugars. Temperature is a crucial factor that significantly affects the conversion of GlcNAc. The yields of AGPNAc and AGFNAc are also drastically changed depending on the reaction conditions. The 5-min reaction at 200 °C is shown to be the optimal condition to generate the 1,6-anhydrosugars with a high efficiency in which AGPNAc and AGFNAc are produced in the yields of 21% and 44%, respectively. Consequently, the microwave-assisted heating reaction of GlcNAc in sulfolane is shown to be a simple and promising pathway to generate 1,6-anhydrosugars consisting of amino monosaccharide backbones, which have high potentials as raw materials leading to biological oligosaccharides and biomimetic polysaccharides.

scholarly journals A Brief Review on Solvent-Free Synthesis of Zeolites

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 788
Author(s):  
Jinlin Mei ◽  
Aijun Duan ◽  
Xilong Wang
Keyword(s):  
High Efficiency ◽  
Raw Materials ◽  
Solvent Free ◽  
High Yield ◽  
Control Synthesis ◽  
Mechanical Mixing ◽  
Synthesis Mechanism ◽  
Wastewater Pollution ◽  
Low Efficiency ◽  
Solvent Free Synthesis

The traditional hydrothermal method to prepare zeolite will inevitably use a large amount of water as a solvent, which will lead to higher autogenous pressure, low efficiency, and wastewater pollution. The solvent-free method can be used to synthesize various types of zeolites by mechanical mixing, grinding, and heating of solid raw materials, which exhibits the apparent advantages of high yield, low pollution, and high efficiency. This review mainly introduces the development process of solvent-free synthesis, preparation of hierarchical zeolite, morphology control, synthesis mechanism and applications of solvent-free methods. It can be believed that solvent-free methods will become a research focus and have enormous industrial application potential.

scholarly journals Microwave-Assisted Asinger Synthesis of Thiazolines

2020 ◽  
Vol 3 (1) ◽  
pp. 27
Author(s):  
Raúl Eduardo Gordillo-Cruz ◽  
Liliana Gonzalez-Reyes ◽  
Milton Coporo-Reyes ◽  
Nieves Zavala-Segovia ◽  
Bernardo A. Frontana-Uribe ◽  
...  
Keyword(s):  
Microwave Irradiation ◽  
Reaction Times ◽  
Reaction Conditions ◽  
Microwave Assisted

An array of 2,4-disubstituted thiazolines was obtained through Asinger reaction approach from the straightforward treatment of diverse aldehydes/ketones with 1-mercaptopropan-2-one, in the presence of NH3 assisted by microwave irradiation, displaying similar and sometimes higher yields, as well as shorter reaction times that traditional Asinger reaction conditions at room and lower temperatures.

Time course changes of vasopressin-induced enlargement of the rat intrastrial space and the effects of a vasopressin type 2 antagonist

2009 ◽  
Vol 129 (7) ◽  
pp. 709-715 ◽  
Author(s):  
Masahiko Nishimura ◽  
Akinobu Kakigi ◽  
Taizo Takeda ◽  
Teruhiko Okada ◽  
Katsumi Doi
Keyword(s):  
Time Course ◽  
Course Changes

Solid-state regioselective nitration of activated hydroxyaromatics and hydroxycoumarins with cerium (IV) ammonium nitrate

2005 ◽  
Vol 2005 (11) ◽  
pp. 733-735 ◽  
Author(s):  
Nemai C. Ganguly ◽  
Sanjoy Dutta ◽  
Mrityunjoy Datta ◽  
Prithwiraj De
Keyword(s):  
Solid State ◽  
Ammonium Nitrate ◽  
High Efficiency ◽  
Solvent Free ◽  
High Melting ◽  
Microwave Assisted ◽  
Solvent Free Conditions ◽  
High Yields ◽  
Regioselective Nitration ◽  
Cerium Iv Ammonium Nitrate

Predominant ortho-selective mononitration of low-melting and liquid phenols and hydroxycoumarins in moderate to high yields has been accomplished upon grinding with solid cerium (IV) ammonium nitrate (CAN). Microwave-assisted expeditious CAN-mediated nitration of relatively high melting phenols and hydroxycoumarins with high efficiency and selectively under solvent-free conditions has been also developed to address the problems of sluggishness and low yield for these reluctant substrates.

Cerebral oxygenation changes in response to motor stimulation

1996 ◽  
Vol 81 (3) ◽  
pp. 1174-1183 ◽  
Author(s):  
H. Obrig ◽  
C. Hirth ◽  
J. G. Junge-Hulsing ◽  
C. Doge ◽  
T. Wolf ◽  
...  
Keyword(s):  
Time Course ◽  
Near Infrared ◽  
Cerebral Oxygenation ◽  
Motor Task ◽  
Hemoglobin Concentration ◽  
Hemodynamic Response ◽  
Blood Oxygenation ◽  
Initial Increase ◽  
Cerebral Hemodynamic ◽  
Course Changes

We studied cerebral hemodynamic response to a sequential motor task in 56 subjects to investigate the time course and distribution of blood oxygenation changes as monitored by near-infrared spectroscopy (NIRS). To address whether response is modulated by different performance velocities, a group of subjects (n = 12) was examined while performing the motor task at 1, 2, and 3 Hz. The results demonstrate that 1) the NIRS response reflects localized changes in cerebral hemodynamics, 2) the response, consisting of an increase in oxygenated hemoglobin concentration [oxy-Hb] and a decrease in deoxygenated hemoglobin concentration ([deoxy-Hb]), is lateralized and increases in amplitude with higher performance rates, and 3) changes in [oxy-Hb] and [deoxy-Hb] differ in time course. Changes in [oxy-Hb] are biphasic, with a fast initial increase and a pronounced poststimulus undershoot. The stimulus-associated decrease in [deoxy-Hb] is monophasic, and response latency is greater. We conclude that NIRS is able to detect even small changes in cerebral hemodynamic response to functional stimulation.

Time-course changes in clinical features of early-onset Japanese type 1 and type 2 diabetes: TWMU hospital-based study

2008 ◽  
Vol 82 (1) ◽  
pp. 80-86 ◽  
Author(s):  
Yasuko Uchigata ◽  
Toshika Otani ◽  
Hiroko Takaike ◽  
Junnosuke Miura ◽  
Mari Osawa ◽  
...  
Keyword(s):  
Type 2 Diabetes ◽  
Clinical Features ◽  
Early Onset ◽  
Time Course ◽  
Course Changes

scholarly journals Application of enzyme engineering in pharmacy

2020 ◽  
Vol 9 (2) ◽  
Author(s):  
Qiaole Li ◽  
Yanhong Li ◽  
Haoran Niu
Keyword(s):  
High Efficiency ◽  
Development Trend ◽  
Enzyme Engineering ◽  
Reaction Conditions ◽  
Important Method ◽  
Reaction Specificity ◽  
Prevention And Treatment ◽  
Modern Biotechnology ◽  
Catalytic Functions ◽  
The Development Trend

Enzyme engineering is an important part of modern biotechnology. Due to its high reaction specificity, high efficiency, mild reaction conditions, and low pollution, it is also an important method widely used in the pharmaceutical field. The application of enzymes in medicine is diverse, such as: diagnosis, prevention and treatment of diseases with enzymes, manufacture of various drugs with enzymes, etc., mainly through manual operations, to obtain enzymes required by the pharmaceutical industry, and through various means Enzymes perform their catalytic functions. This article mainly introduces the application of enzyme engineering in the pharmaceutical field, and also prospects the development trend of enzyme engineering in the pharmaceutical field.

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