Ionic Liquids-Prompted Synthesis of Biologically Relevant Five- and Six-Membered Heterocyclic Skeletons

2015 ◽  
pp. 437-493 ◽  
Author(s):  
Bhuwan B. Mishra ◽  
Dhananjay Kumar ◽  
Anoop S. Singh ◽  
Rama P. Tripathi ◽  
Vinod K. Tiwari
Keyword(s):  
Ionic Liquids ◽  
Biologically Relevant

Room-Temperature Ionic Liquids in Glycoscience: Opportunities and Challenges+

2021 ◽  
Vol 25 ◽  
Author(s):  
Sanchayita Rajkhowa ◽  
Raju R. Kale ◽  
Jyotirmoy Sarma ◽  
Abhijeet Kumar ◽  
Prabhu P. Mohapatra ◽  
...  
Keyword(s):  
Ionic Liquids ◽  
Room Temperature ◽  
Materials Science ◽  
High Yield ◽  
Easy Access ◽  
Room Temperature Ionic Liquids ◽  
Green Solvents ◽  
Diverse Range ◽  
Biologically Relevant ◽  
Wide Range

: Carbohydrates are fascinating molecular scaffolds known for their diverse applications in chemistry, biology, medicine, technology, and materials science. In addition, owing to the notable features of room-temperature ionic liquids (RTILs) such as high yield, short reaction time, simple handling, excellent recyclability, and environmentally benign nature, they have been extensively utilized as green solvents, catalysts, or both in a wide range of organic transformation methodologies for easy access of a diverse range of biologically relevant molecules. This review highlights the importance of RTILs that offer promising solutions in glycoscience, particularly in relevance to the dissolution, functionalization, glycosylation, and modification of carbohydrates as well as their challenges, impact, and future perspectives.

An Efficient and Ecofriendly Three-Component Reaction for the Rapid Synthesis of 2-Amino-4H-chromenes Catalyzed by a DABCO­-Based Ionic Liquid

Synthesis ◽  
2018 ◽  
Vol 50 (18) ◽  
pp. 3708-3714 ◽  
Author(s):  
Da-Zhen Xu ◽  
Cheng-Bin Li ◽  
Yu-Wei Li
Keyword(s):  
Ionic Liquid ◽  
Ionic Liquids ◽  
Michael Reaction ◽  
Reaction Times ◽  
Rapid Synthesis ◽  
Biologically Relevant ◽  
Mild Conditions ◽  
Three Component Reaction ◽  
Green Strategy

An efficient, economical, and green strategy for the construction of biologically relevant 2-amino-4H-chromene scaffolds via a tandem Knoevenagel–Pinner cyclization–Michael reaction has been successfully developed. In the presence of DABCO-based ionic liquids, two different 2-amino-4H-chromene derivatives, 2-amino-4-(indol-3-yl)-4H-chromenes and 2-amino-4-(pyrazol-4-yl)-4H-chromenes, were prepared in good to excellent yields (81–97%) within short reaction times under mild conditions. All the products are purified by simple crystallization. The catalyst could be recycled for at least five times.

Investigation of thin sections of biological standards by EDX, EELS, and Auger electron spectroscopy

1990 ◽  
Vol 48 (2) ◽  
pp. 184-185
Author(s):  
S. Lehner ◽  
H.E. Bauer ◽  
R. Wurster ◽  
H. Seiler
Keyword(s):  
Processing System ◽  
Beam Current ◽  
Beam Diameter ◽  
Thin Sections ◽  
Biologically Relevant ◽  
Energy Filtering ◽  
Low Viscosity ◽  
Carbon Foils ◽  
Electron Microscopical ◽  
Exchange Membrane

In order to compare different microanalytical techniques commercially available cation exchange membrane SC-1 (Stantech Inc, Palo Alto), was loaded with biologically relevant elements as Na, Mg, K, and Ca, respectively, each to its highest possible concentration, given by the number concentration of exchangeable binding sites (4 % wt. for Ca). Washing in distilled water, dehydration through a graded series of ethanol, infiltration and embedding in Spurr’s low viscosity epoxy resin was followed by thin sectioning. The thin sections (thickness of about 50 nm) were prepared on carbon foils and mounted on electron microscopical finder grids.The samples were analyzed with electron microprobe JXA 50A with transmitted electron device, EDX system TN 5400, and on line operating image processing system SEM-IPS, energy filtering electron microscope CEM 902 with EELS/ESI and Auger spectrometer 545 Perkin Elmer.With EDX, a beam current of some 10-10 A and a beam diameter of about 10 nm, a minimum-detectable mass of 10-20 g Ca seems within reach.

Quantification of cell-surface expressed antigenic sites with 5-nm gold markers: Getting close to biologically relevant data

1989 ◽  
Vol 47 ◽  
pp. 1050-1051
Author(s):  
Etienne de Harven ◽  
Hilary Christensen ◽  
Richard Leung ◽  
Cameron Ackerley
Keyword(s):  
Cell Surface ◽  
Human Peripheral Blood ◽  
Contour Length ◽  
Thin Sections ◽  
Gold Particles ◽  
Biologically Relevant ◽  
Transmission Electron ◽  
Entire Cell ◽  
Electron Imaging ◽  
Cell Contour

The T-derived subset of human peripheral blood normal lymphocytes has been selected as a model system to study the usefulness of 5 nm gold markers for quantification of single epitopes expressed on cell surfaces. The chosen epitopes are parts of the CD3 and CD5 molecules and can be specifically identified by hybridoma produced monoclonal antibodies (MoAbs; LEU-4 and LEU-1; Becton-Dick- inson, Mountain view, CA) . An indirect immunolabeling procedure, with goat anti-murine IgG adsorbed on the surface of 5 nm colloidal gold particles (GAM-G5, Janssen Pharmaceutica, Beerse, Belgium) has been used. Backscattered Electron Imaging (BEI) in a field emission scanning electronmicroscope (SEM) and transmission electron microscopy of thin sections of lymphocytes labeled before plastic embedding, were both used to identify and quantitate gold labeled cell surface sites, Estimating that the thickness of “silver” sections is approximately 60 nm and counting the number of gold particles on the entire cell perimeter, we calculated that, for LEU-4, the number of markers per um2 of cell surface is in the 140-160 range (Fig.l). Cell contour length measurements indicated that the surface of one lymphocyte is approximately 130-160 um2 that of a smooth sphere of identical diameter, reflecting the role of microvilli in expanding the surface area. The total number of gold labeled sites on the surface of one lymphocyte averages, therefore between 20,000 and 24,000 per cell.

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