The Easy Approach to N-Hydroxy-N-cycloalkenylamides through Nitrosocarbonyl Ene Reactions to Cycloalkenes: Valuable Compounds for Antiviral Syntheses

Synthesis ◽  
2018 ◽  
Vol 51 (06) ◽  
pp. 1383-1390 ◽  
Author(s):  
Paolo Quadrelli ◽  
Karzan Hameed ◽  
Ahmed Amin ◽  
Faiq Hussain ◽  
Misal Memeo ◽  
...  
Keyword(s):  
Organic Synthesis ◽  
Biologically Active ◽  
Thermal Generation ◽  
Ene Reactions ◽  
Ene Reaction ◽  
Valuable Compounds ◽  
Cyclic Alkenes

An easy approach to N-hydroxy-N-cycloalkenylamides, ene adducts of cyclic alkenes of different sizes, is presented. The products can be obtained both through the thermal generation of the nitrosocarbonyl intermediates and via the photochemical fragmentation of the Wieland heterocycle, this being the mildest way to generate these fleeting species, also affording the best results so far in terms of chemical yields. The use of the ene reaction for the synthesis of biologically active molecules represents an interesting and valuable aspect of modern organic synthesis, and this is the strategy proposed as a remarkable alternative to current methods.

scholarly journals Palladium-Catalyzed Coupling Reactions on Functionalized 2-Trifluoromethyl-4-chromenone Scaffolds: Synthesis of Highly Functionalized Trifluoromethyl Heterocycles

Synthesis ◽  
2018 ◽  
Vol 51 (06) ◽  
pp. 1342-1352 ◽  
Author(s):  
Javier Izquierdo ◽  
Atul Jain ◽  
Sarki Abdulkadir ◽  
Gary Schiltz
Keyword(s):  
Natural Products ◽  
Organic Synthesis ◽  
Biological Activities ◽  
Structural Complexity ◽  
Biologically Active ◽  
Coupling Reactions ◽  
Trifluoromethyl Group ◽  
Palladium Catalyzed ◽  
Active Natural

The chromenone core is an ubiquitous group in biologically active natural products and has been extensively used in organic synthesis. Fluorine-derived compounds, including those with a trifluoromethyl group (CF3), have shown enhanced biological activities in numerous pharmaceuticals compared with their non-fluorinated analogues. 2-Trifluoromethylchromenones can be readily functionalized at the 8- and 7-positions, providing chromenones cores of high structural complexity, which are excellent precursors for numerous trifluoromethyl heterocycles.

scholarly journals Zur Reaktivität des Germaethens Me2Ge=C(SiMe3)2: Mechanistische Aspekte der Diels-Aider- und En-Reaktionen [1] / On the Reactivity of Germaethene Me2Ge=C (SiMe3)2: Mechanistic Aspects of Diels Alder and Ene Reactions [1]

1996 ◽  
Vol 51 (6) ◽  
pp. 838-850 ◽  
Author(s):  
Nils Wiberg ◽  
Susanne Wagner
Keyword(s):  
Double Bond ◽  
Energy Difference ◽  
Diels Alder ◽  
Bond Polarity ◽  
Ene Reactions ◽  
Ene Reaction

Abstract Diels-Alder and ene reactions of germaethene Me2Ge=C(SiMe3)2 (2) with butadienes respectively, take place regioselectively, as well as stereoselectively. They are accelerated by an increasing tendency of substituents in butadiene or propene to donate electrons (e.g. 2-methylbutadiene > butadiene; 2-methylpropene > propene), and retarded by an increasing bulkyness of substituents in 1,4- or 1,3-positions (e.g. 1-methylbutadiene > 2-methylbutadiene; 1-vinylpropene > propene). It is concluded from these studies that Diels-Alder and ene reactions of 2 occur - like those of Me2Si=C(SiMe3)2 (1) or of ethenes >C=C< - in a concerted way and are HOMOdiene-LUMOdienophile and HOMOene-LUMOenophile controlled. Thus 2 and 1 behave as carbon analogues. With regard to a specific diene or ene (e.g. anthracene; toluene), 2 is the better dienophile or enophile than 1 or ethenes. With a fixed diene/ene mixture (e.g. butadiene/propene), 2 acts as the better dienophile, while 1 is the better enophile. These results can be explained by the π/π*- energy difference and the double bond polarity decreasing in the direction 1 > 2. Only cis-piperylene gives a [2+2] cycloadduct with 2. besides two [4+2] cycloadducts, and an ene reaction product

Nitrosocarbonyl Carbohydrate Derivatives: Hetero Diels–Alder and Ene Reaction Products for Useful Organic Synthesis

Synthesis ◽  
2020 ◽  
Author(s):  
Paolo Quadrelli ◽  
Marco Corti ◽  
Marco Leusciatti ◽  
Mattia Moiola ◽  
Mariella Mella
Keyword(s):  
Organic Synthesis ◽  
Tertiary Amine ◽  
Diels Alder ◽  
Mild Oxidation ◽  
Reaction Products ◽  
Ene Reaction ◽  
Nitrile Oxides

AbstractThe generation and trapping of two new nitrosocarbonyl intermediates bearing carbohydrate-based chiral substituents is achieved by the mild oxidation of the corresponding nitrile oxides with tertiary amine N-oxides. Their capture with suitable dienes and alkenes afforded the corresponding hetero Diels–Alder cycloadducts and ene adducts from fair to excellent yields. The entire methodology looks highly promising by the easy conversion of aldoximes into hydroxymoyl halides, widening the access to nitrosocarbonyls, versatile tools in organic synthesis.

scholarly journals Ruthenium catalysis in organic synthesis

2002 ◽  
Vol 74 (1) ◽  
pp. 19-24 ◽  
Author(s):  
Shun-Ichi Murahashi ◽  
Hikaru Takaya ◽  
Takeshi Naota
Keyword(s):  
Organic Synthesis ◽  
Lewis Acid ◽  
Catalytic Reactions ◽  
Biologically Active ◽  
Hydride Complexes ◽  
Base Catalysts ◽  
Acid And Base ◽  
Ruthenium Catalysis ◽  
Lewis Acid And Base ◽  
Neutral Conditions

Ruthenium, rhodium, iridium, and rhenium hydride complexes are highly useful redox Lewis acid and base catalysts. Various substrates bearing hetero atoms are activated by these catalysts and undergo reactions with either nucleophiles or electrophiles under neutral conditions. These types of catalytic reactions are described together with their application to the preparation of various biologically active compounds.

scholarly journals Microalgae: A Promising Source of Valuable Bioproducts

Biomolecules ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 1153 ◽  
Author(s):  
Vyacheslav Dolganyuk ◽  
Daria Belova ◽  
Olga Babich ◽  
Alexander Prosekov ◽  
Svetlana Ivanova ◽  
...  
Keyword(s):  
New Technologies ◽  
Value Added ◽  
Component Composition ◽  
Biologically Active Substances ◽  
Biologically Active ◽  
High Productivity ◽  
Advantages And Disadvantages ◽  
Valuable Compounds ◽  
Promising Source ◽  
Active Substances

Microalgae are a group of autotrophic microorganisms that live in marine, freshwater and soil ecosystems and produce organic substances in the process of photosynthesis. Due to their high metabolic flexibility, adaptation to various cultivation conditions as well as the possibility of rapid growth, the number of studies on their use as a source of biologically valuable products is growing rapidly. Currently, integrated technologies for the cultivation of microalgae aiming to isolate various biologically active substances from biomass to increase the profitability of algae production are being sought. To implement this kind of development, the high productivity of industrial cultivation systems must be accompanied by the ability to control the biosynthesis of biologically valuable compounds in conditions of intensive culture growth. The review considers the main factors (temperature, pH, component composition, etc.) that affect the biomass growth process and the biologically active substance synthesis in microalgae. The advantages and disadvantages of existing cultivation methods are outlined. An analysis of various methods for the isolation and overproduction of the main biologically active substances of microalgae (proteins, lipids, polysaccharides, pigments and vitamins) is presented and new technologies and approaches aimed at using microalgae as promising ingredients in value-added products are considered.

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