Monoacetylation of Carbohydrate Diols via Transesterification with Ethyl Acetate

2014 ◽  
Vol 67 (4) ◽  
pp. 679 ◽  
Author(s):  
Xuyu Liu ◽  
Bernd Becker ◽  
Matthew A. Cooper
Keyword(s):  
Ethyl Acetate ◽  
Efficient Method ◽  
New Method ◽  
Protecting Groups ◽  
Acyl Donor

Monoacetylation of secondary diols in protected monosaccharides was achieved with ethyl acetate as acyl donor and sodium tert-butoxide as a base. The regioseletivity of the reaction varied depending on the substrate. This new method provides a simple, fast, and efficient method to access selectively acetylated carbohydrates that is compatible with acid-sensitive protecting groups.

HSCCC Separation of Three Main Compounds from the Crude Extract of Dracocephalum Tanguticum by Using Dimethyl Sulfoxide as Cosolvent

2020 ◽  
Author(s):  
Xue Yang ◽  
Yongling Liu ◽  
Tao Chen ◽  
Nana Wang ◽  
Hongmei Li ◽  
...  
Keyword(s):  
Acetic Acid ◽  
Ethyl Acetate ◽  
Dimethyl Sulfoxide ◽  
Efficient Method ◽  
Crude Extract ◽  
High Speed ◽  
Glacial Acetic Acid ◽  
Butyl Alcohol ◽  
Preparative Hplc ◽  
Counter Current

Abstract Separation of natural compounds directly from the crude extract is a challenging work for traditional column chromatography. In the present study, an efficient method for separation of three main compounds from the crude extract of Dracocephalum tanguticum has been successfully established by high-speed counter-current chromatography (HSCCC). The crude extract was directly introduced into HSCCC by using dimethyl sulfoxide as cosolvent. Ethyl acetate/n-butyl alcohol/0.3% glacial acetic acid (4: 1: 5, v/v) system was used and three target compounds with purity higher than 80% were obtained. Preparative HPLC was used for further purification and three target compounds with purity higher than 98% were obtained. The compounds were identified as chlorogenic acid, pedaliin and pedaliin-6″-acetate.

A New Method for Railway Fastener Detection Using the Symmetrical Image and Its EA-HOG Feature

2019 ◽  
Vol 34 (02) ◽  
pp. 2055006
Author(s):  
Jiajia Liu ◽  
Jianying Yuan ◽  
Yongfang Jia
Keyword(s):  
Computer Vision ◽  
Sparse Representation ◽  
Efficient Method ◽  
Important Task ◽  
New Method ◽  
Automatic Inspection ◽  
Test Image ◽  
Recognition Result ◽  
The Status ◽  
Railway Operation

Railway fastener recognition and detection is an important task for railway operation safety. However, the current automatic inspection methods based on computer vision can effectively detect the intact or completely missing fasteners, but they have weaker ability to recognize the partially worn ones. In our method, we exploit the EA-HOG feature fastener image, generate two symmetrical images of original test image and turn the detection of the original test image into the detection of two symmetrical images, then integrate the two recognition results of symmetrical image to reach exact recognition of original test image. The potential advantages of the proposed method are as follows: First, we propose a simple yet efficient method to extract the fastener edge, as well as the EA-HOG feature of the fastener image. Second, the symmetry images indeed reflect some possible appearance of the fastener image which are not shown in the original images, these changes are helpful for us to judge the status of the symmetry samples based on the improved sparse representation algorithm and then obtain an exact judgment of the original test image by combining the two corresponding judgments of its symmetry images. The experiment results show that the proposed approach achieves a rather high recognition result and meets the demand of railway fastener detection.

Synthesis of the 5-Fluoro-4-hydroxypentyl Side Chain Metabolites of Synthetic Cannabinoids 5F-APINACA and CUMYL-5F-PINACA

Synthesis ◽  
2018 ◽  
Vol 50 (23) ◽  
pp. 4683-4689 ◽  
Author(s):  
Mark Trudell ◽  
Ryan McKinnie ◽  
Tasneam Darweesh ◽  
Phoebe Zito ◽  
Terrell Shields
Keyword(s):  
Efficient Method ◽  
Synthetic Cannabinoids ◽  
Synthetic Cannabinoid ◽  
Protecting Groups ◽  
Side Chain ◽  
Hydroxy Metabolites

An efficient method for the construction of the 5-fluoro-4-hydroxypentyl side chain common to a number of synthetic cannabinoid metabolites was developed. A series of hydroxyl protecting groups was examined to assess the viability as orthogonal protecting groups for epoxidation and regioselective hydrofluorination. The 1-[5-fluoro-4-(diphenyl-tert-butylsilyloxy)]pentyl tosylate was prepared in 67% overall yield (six steps) from pent-4-en-1-ol and was employed for the synthesis of the 4-hydroxy metabolites of the synthetic cannabinoid 5F-APINACA and CUMYL-5F-PINACA.

scholarly journals A Simple and Efficient Method to Isolate LTR Sequences of Plant Retrotransposon

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Da-Long Guo ◽  
Xiao-Gai Hou ◽  
Xi Zhang
Keyword(s):  
Molecular Markers ◽  
Efficient Method ◽  
High Efficiency ◽  
Size Structure ◽  
Restriction Enzymes ◽  
Rnase H ◽  
Plant Genome ◽  
New Method ◽  
Tree Peony ◽  
Time Saving

Retrotransposons (RTNs) have important roles in the formation of plant genome size, structure, and evolution. Ubiquitous distributions, abundant copy numbers, high heterogeneities, and insertional polymorphisms of RTNs have made them as excellent sources for molecular markers development. However, the wide application of RTNs-based molecular markers is restricted by the scarcity of the LTR (long terminal repeat) sequences information. A new, simple, and efficient method to isolate LTR sequences of RTNs was presented based on the degenerate RNase H nested primers and PPT (polypurine tract) primer of RTNs in tree peony. This method combined the characteristics and advantages of high-efficiency thermal asymmetric interlaced PCR (hiTAIL-PCR), annealing control primer (ACP) system, and suppression PCR method. Nineteen LTR sequences were isolated using this new method in tree peony and the applicability of the LTR sequences based markers was validated by further SSAP analysis. The results showed that the new method is simple, of low-cost, and highly efficient, which is just conducted by three rounds of PCR and does not need any restriction enzymes and adapters, much less the hybridizations. This new method is rapid, economical, and cost- and time-saving, which could be easily used to isolate LTR sequences of RTNs.

Synthesis of precipitating chromogenic/fluorogenic β-glucosidase/β-galactosidase substrates by a new method and their application in the visual detection of foodborne pathogenic bacteria

2017 ◽  
Vol 53 (1) ◽  
pp. 103-106 ◽  
Author(s):  
Xianhu Wei ◽  
Qingping Wu ◽  
Jumei Zhang ◽  
Youxiong Zhang ◽  
Weipeng Guo ◽  
...  
Keyword(s):  
Efficient Method ◽  
Pathogenic Bacteria ◽  
Visual Detection ◽  
New Method ◽  
Foodborne Pathogenic Bacteria

Some indoxyl β-glycosides and novel precipitating fluorogenic β-glucosides were synthesized by a new efficient method and applied for detecting bacteria.

scholarly journals An Automatic High Efficient Method for Dish Concentrator Alignment

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Yong Wang ◽  
Song Li ◽  
Jinshan Xu ◽  
Yijiang Wang ◽  
Xu Cheng ◽  
...  
Keyword(s):  
Solar Energy ◽  
Efficient Method ◽  
Isosceles Triangle ◽  
Energy System ◽  
Light Spot ◽  
New Method ◽  
Automatic Determination ◽  
High Efficient ◽  
Key Factor

Alignment of dish concentrator is a key factor to the performance of solar energy system. We propose a new method for the alignment of faceted solar dish concentrator. The isosceles triangle configuration of facet’s footholds determines a fixed relation between light spot displacements and foothold movements, which allows an automatic determination of the amount of adjustments. Tests on a 25 kW Stirling Energy System dish concentrator verify the feasibility, accuracy, and efficiency of our method.

scholarly journals A New Method for Transcarbamation and Amidation from Benzyl Carbamate

2020 ◽  
Author(s):  
sudershan gondi
Keyword(s):  
Potassium Carbonate ◽  
Efficient Method ◽  
New Method ◽  
Heating Condition

<div>Abstracts: A convenient, and efficient method for Transcarbamation and conversion of</div><div>benzyl carbamates to amide using potassium carbonate in alcohols under heating condition</div><div>is described.</div>

Efficient Method for Aziridination of Olefines

1993 ◽  
Vol 58 (7) ◽  
pp. 1705-1710 ◽  
Author(s):  
Madhukar B. Hogale ◽  
Pravina B. Chavan
Keyword(s):  
Efficient Method ◽  
New Method

New method for aziridination of olefinic esters is described.

scholarly journals An Efficient Method for Geometric Modeling of 3D Braided Composites

2016 ◽  
Vol 11 (4) ◽  
pp. 155892501601100 ◽  
Author(s):  
Qi Wang ◽  
Ronghua Zhang ◽  
Jianming Wang ◽  
Yanan Jiao ◽  
Xiaohui Yang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Efficient Method ◽  
Geometric Modeling ◽  
Three Dimensional ◽  
Structure Design ◽  
New Method ◽  
Braided Composites ◽  
3D Braided Composites ◽  
Cad Simulation ◽  
Geometric Study

To estimate the precise mechanical properties of a three-dimensional (3D) braided composite, a geometric study is needed. Because of the complexity of the yarn paths inside the preform, the geometric modeling for 3D braided composites is always time consuming. In this paper, an efficient method, namely preform boundary reflection (PBR), is proposed for motion model construction in geometric studies. Furthermore, a CAD simulation system using novel combinations of parameters was developed for integral geometric descriptions of 3D braided preforms. Compared with the traditional method, the new method significantly simplifies the simulation process without affecting the precision of geometric structure. As a result, the structure design for composite preforms is effectively accelerated. The new method establishes a foundation for microstructure and mechanical properties analysis of preforms with complex geometric structures.

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