Arylidenemalononitriles as Versatile Synthons in Heterocyclic Synthesis

2022 ◽  
Vol 19 ◽  
Author(s):  
Pannala Padmaja ◽  
Subba Reddy ◽  
Vinod G. Ugale ◽  
Pedavenkatagari Narayana Reddy
Keyword(s):  
Heterocyclic Compounds ◽  
Biological Science ◽  
Heterocyclic Synthesis ◽  
Preparation Methods ◽  
Spirocyclic Compounds ◽  
Novel Complex

Background: Objective: Objective: biological science.: Background: Arylidenemalononitriles are valuable synthons for the construction of a variety of novel complex heterocyclic motifs, fused heterocycle derivatives and spirocyclic compounds. They are versatile chemical intermediates and have increasing applications in industry, agriculture, medicine, Objective: The aim of this review is to highlight the preparation methods and reactions of arylidenemalononitriles in the synthesis of various heterocyclic compounds. Conclusion: n this review, we have presented the application of arylidenemalononitriles to construct a variety of heterocycles. Various catalysts for the preparation of arylidnemalononitriles have been described.

Recent Advances in C-C/Heteroatom Bond Forming and Annulation Reactions of β-Ketodithioesters

2021 ◽  
Vol 18 ◽  
Author(s):  
Laishram Momota Devi ◽  
Thokchom Prasanta Singh ◽  
Okram Mukherjee Singh
Keyword(s):  
Heterocyclic Compounds ◽  
Multicomponent Reactions ◽  
Building Blocks ◽  
Heterocyclic Synthesis ◽  
Bond Forming ◽  
Mild Conditions ◽  
The Past ◽  
Rapid Construction ◽  
Fresh Perspective ◽  
Good Number

: β Ketodithioesters (KDEs) are versatile building blocks for the rapid construction of various heterocyclic compounds. Quite a good number of successful reactions based on KDEs have been developed in the past decade for the construction of heterocyclic skeletons under mild conditions. This review covers the new C-C/X bond formation and annulation reactions of KDEs with dielectrophilic or dinucleophilic reagents. Multicomponent reactions using KDEs to construct various heterocycles are also the major contents in this review. Objective: The aim of this review is to bring a fresh perspective on the application of KDEs in organic synthesis covering from 2013 to 2020. Conclusion: From this review, it is clear that KDEs have been the object of numerous studies on its use in heterocyclic synthesis. The presence of different functional groups on this synthon permits the incorporation of C-C/X sources into the final targets, which is the beauty of KDEs.

scholarly journals Synthesis of Some Heterocyclic Compounds Derived from Furfural

2018 ◽  
Vol 2 (1) ◽  
Keyword(s):  
Sodium Azide ◽  
Ring Opening ◽  
Heterocyclic Compounds ◽  
Pyrimidine Derivative ◽  
Heterocyclic Synthesis ◽  
Pyrimidine Derivatives ◽  
Triazole Derivatives ◽  
The Third

We know that most heterocyclic compounds are drugs or co- drugs. In our investigation furfural was used as a precursor for heterocyclic synthesis, either by ring opening of furfural going to pyrimidine derivative E3 then functionalizing this pyrimidine into its derivatives E8, E10 and cyclization into oxadiazole and thiadiazoles E8, 11. Or the reaction of pyrimidine with dimedon derivatives to afford dimedino pyrimidine derivatives. The second pathway involve the synthesis of oxamyl derivative of pyrmidine E21-25 these compounds were cyclized into new oxadiazoles E24-26. The third pathway involve the synthesis of mucobromic esters E27-29 from MBA acid then these esters were converted into the correspondig lactones E30-32 and E32-36 while reacting MBA with amines affording N-alkyland N-amidolactams. The last pathway was the reaction MBA with methanol, sodium azide to give azidointermeddiate which was cyclized with alkene or alkynes into triazole derivatives E42-49. The synthesized compounds were characterized by IR and some 1 HNMR measurements.

Fischer carbene complexes. A new tool for heterocyclic synthesis

2002 ◽  
Vol 74 (8) ◽  
pp. 1317-1325 ◽  
Author(s):  
José Barluenga
Keyword(s):  
Michael Addition ◽  
Heterocyclic Compounds ◽  
Short Review ◽  
Enantioselective Synthesis ◽  
Heterocyclic Synthesis ◽  
Fischer Carbene Complexes ◽  
Carbene Complexes ◽  
Fischer Carbene ◽  
Stereogenic Centers ◽  
Sequential Processes

This short review covers our contribution in the field of the application of group 6 Fischer carbene complexes toward the synthesis of heterocyclic compounds. Alkenyl and alkynyl carbene complexes are suitable partners in [2+2], [3+2], [4+2], and [4+3] cycloaddition reactions. Moreover, chiral alkenyl carbene complexes react in sequential processes involving an initial Michael addition of a ketone lithium enolate to afford lactones with up to five consecutive stereogenic centers. Based on this strategy, we have devised a new method for the enantioselective synthesis of eight-membered carbocycles.

Green Multi-Component Synthesis of Fused heterocyclic derivatives: An atom economic ecofriendly approach for complex molecules

2021 ◽  
Vol 09 ◽  
Author(s):  
Ravikumar Dhanalakshmi ◽  
Gopal Jeya ◽  
Murugan Anbarasu ◽  
Vajiravelu Sivamurugan
Keyword(s):  
Heterocyclic Compounds ◽  
Multicomponent Reactions ◽  
Primary Objective ◽  
Single Step ◽  
Indole Derivatives ◽  
Heterocyclic Synthesis ◽  
Complex Molecules ◽  
Fused Heterocycles ◽  
Heterocyclic Derivatives ◽  
Recent Trends

Background: The construction of fused heterocyclic compounds is always fascinating on the strength of their applications as novel pharmaceuticals. Multi-component reactions (MCRs) are atom economical, beneficial, straightforward and ecofriendly approach for synthesis of complex heterocycles in a single step with higher selectivity. Methods: The review mainly focused on the synthesis of fused heterocycles such as pyrimidine - chromene, Pyrrolo - pyrazine, Pyrazolo - pyrimidine, pyran - imidazole and pyrazole- imidazole - pyrimidine, pyran - pyridmidone, pyrrolo - chromene, pyridine-pyrimidinone, fused indole derivatives, furano - pyran along with some simple MCRs discussed, which published in in the period of 2019 and 2020. A table of summary about 50 heterocycles with product, catalysts and cited literature for are given at end. Conclusions: From this review we understand that MCRs can deliver an effortless access to molecular targets of our interest with wide choice of reactants and their combinations. Thus, the creativity and choice of reactants are pushing the development in MCRs towards more atom economical and eco-friendly approach Objective: Understanding recent trends in the development of MCRs is a requisite for anyone, who wish to synthesise simple and fused heterocycles. By keeping this as primary objective, the present review provides an overview of latest developments in fused heterocyclic synthesis via green multicomponent reactions in the period of 2019 and 2020.

Pyrimidinethione as a building block in heterocyclic synthesis: synthesis of pyrano[2,3-d]pyrimidine, chromeno[2,3-d]pyrimidine, pyrido[3′,2′:5,6]pyrano[2,3-b]pyridine, and pyrimido[5′,4′:5,6]pyrano[2,3-d]pyrimidine derivatives

2016 ◽  
Vol 22 (6) ◽  
Author(s):  
Mohamed Ahmed Mahmoud Abdel Reheim ◽  
Ibrahim Saad Abdel Hafiz ◽  
Mohamed Ahmed Elian
Keyword(s):  
Biological Activity ◽  
Building Block ◽  
Heterocyclic Compounds ◽  
Heterocyclic Synthesis ◽  
Pyrimidine Derivatives

AbstractNew heterocyclic compounds with expected biological activity have been prepared by reactions of 6-phenyl-2-thioxo-2,3-dihydropyrimidine-4(5

Electron microscopic studies on ultrathin frozen sections of lactating mouse mammary gland

1978 ◽  
Vol 36 (2) ◽  
pp. 46-47
Author(s):  
Jan Zarzycki ◽  
Joseph Szroeder
Keyword(s):  
Mammary Gland ◽  
Protein Denaturation ◽  
Chemical Constituents ◽  
Freeze Substitution ◽  
Electron Microscopic Examination ◽  
Mouse Mammary Gland ◽  
Electron Microscopic ◽  
Preparation Methods ◽  
Microscopic Studies ◽  
Ultrathin Frozen Sections

The mammary gland ultrastructure in various functional states is the object of our investigations. The material prepared for electron microscopic examination by the conventional chemical methods has several limitations, the most important are the protein denaturation processes and the loss of large amounts of chemical constituents from the cells. In relevance to this,one can't be sure about a degree the observed images are adequate to the realy ultrastructure of a living cell. To avoid the disadvantages of the chemical preparation methods,some autors worked out alternative physical methods based on tissue freezing / freeze-drying, freeze-substitution, freeze-eatching techniqs/; actually the technique of cryoultraraicrotomy,i,e.cutting ultrathin sections from deep frozen specimens is assented as a complete alternative method. According to the limitations of the routine plastic embbeding methods we were interested to analize the mammary gland ultrastructure during lactation by the cryoultramicrotomy method.

Enhancement of Contrast in the CEM and STEM Using Bumpy Specimens and Employing the “Dappled Field” Mode of Operation

1974 ◽  
Vol 32 ◽  
pp. 552-553 ◽  
Author(s):  
L. Gandolfi ◽  
J. Reiffel
Keyword(s):  
Operating Mode ◽  
Scanning Transmission Electron Microscope ◽  
Dark Field ◽  
Specimen Preparation ◽  
Field Mode ◽  
Preparation Methods ◽  
Scanning Transmission Electron ◽  
Transmission Electron ◽  
Mode Of Operation ◽  
Scanning Transmission

Calculations have been performed on the contrast obtainable, using the Scanning Transmission Electron Microscope, in the observation of thick specimens. Recent research indicates a revival of an earlier interest in the observation of thin specimens with the view of comparing the attainable contrast using both types of specimens.Potential for biological applications of scanning transmission electron microscopy has led to a proliferation of the literature concerning specimen preparation methods and the controversy over “to stain or not to stain” in combination with the use of the dark field operating mode and the same choice of technique using bright field mode of operation has not yet been resolved.

Structure-property relations of liquid crystalline polymers

1987 ◽  
Vol 45 ◽  
pp. 460-463
Author(s):  
Linda C. Sawyer
Keyword(s):  
Solid State ◽  
Liquid Crystalline ◽  
Structural Model ◽  
Crystalline Polymer ◽  
Liquid Crystalline Polymers ◽  
Mechanical Anisotropy ◽  
Structure Property ◽  
Preparation Methods ◽  
Crystalline Polymers ◽  
Extended Chain

Recent liquid crystalline polymer (LCP) research has sought to define structure-property relationships of these complex new materials. The two major types of LCPs, thermotropic and lyotropic LCPs, both exhibit effects of process history on the microstructure frozen into the solid state. The high mechanical anisotropy of the molecules favors formation of complex structures. Microscopy has been used to develop an understanding of these microstructures and to describe them in a fundamental structural model. Preparation methods used include microtomy, etching, fracture and sonication for study by optical and electron microscopy techniques, which have been described for polymers. The model accounts for the macrostructures and microstructures observed in highly oriented fibers and films.Rod-like liquid crystalline polymers produce oriented materials because they have extended chain structures in the solid state. These polymers have found application as high modulus fibers and films with unique properties due to the formation of ordered solutions (lyotropic) or melts (thermotropic) which transform easily into highly oriented, extended chain structures in the solid state.

DNA nick end labeling: a reliable marker for apoptosis?

1995 ◽  
Vol 53 ◽  
pp. 962-963
Author(s):  
Anne F. Bushnell ◽  
Sarah Webster ◽  
Lynn S. Perlmutter
Keyword(s):  
Cell Death ◽  
Cultured Cells ◽  
Apoptotic Cell ◽  
Morphological Characteristics ◽  
Detection Methods ◽  
Tissue Preparation ◽  
Preparation Methods ◽  
Dna Laddering ◽  
Disease States ◽  
Reliable Marker

Apoptosis, or programmed cell death, is an important mechanism in development and in diverse disease states. The morphological characteristics of apoptosis were first identified using the electron microscope. Since then, DNA laddering on agarose gels was found to correlate well with apoptotic cell death in cultured cells of dissimilar origins. Recently numerous DNA nick end labeling methods have been developed in an attempt to visualize, at the light microscopic level, the apoptotic cells responsible for DNA laddering.The present studies were designed to compare various tissue processing techniques and staining methods to assess the occurrence of apoptosis in post mortem tissue from Alzheimer's diseased (AD) and control human brains by DNA nick end labeling methods. Three tissue preparation methods and two commercial DNA nick end labeling kits were evaluated: the Apoptag kit from Oncor and the Biotin-21 dUTP 3' end labeling kit from Clontech. The detection methods of the two kits differed in that the Oncor kit used digoxigenin dUTP and anti-digoxigenin-peroxidase and the Clontech used biotinylated dUTP and avidinperoxidase. Both used 3-3' diaminobenzidine (DAB) for final color development.

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