Synthetic organic reactions that use reactions between unsaturated molecules to form cyclical products.
Changing an open-chain hydrocarbon to a closed ring. (McGraw-Hill Dictionary of Scientific and Technical Terms, 5th ed)
Hydrocarbons with at least one triple bond in the linear portion, of the general formula Cn-H2n-2.
Organic chemistry methodology that mimics the modular nature of various biosynthetic processes. It uses highly reliable and selective reactions designed to "click" i.e., rapidly join small modular units together in high yield, without offensive byproducts. In combination with COMBINATORIAL CHEMISTRY TECHNIQUES, it is used for the synthesis of new compounds and combinatorial libraries.
Rhodium. A hard and rare metal of the platinum group, atomic number 45, atomic weight 102.905, symbol Rh. (Dorland, 28th ed)
The phenomenon whereby compounds whose molecules have the same number and kind of atoms and the same atomic arrangement, but differ in their spatial relationships. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 5th ed)
Organic or inorganic compounds that contain the -N3 group.
Acyclic branched or unbranched hydrocarbons having two carbon-carbon double bonds.
Unsaturated hydrocarbons of the type Cn-H2n, indicated by the suffix -ene. (Grant & Hackh's Chemical Dictionary, 5th ed, p408)
The location of the atoms, groups or ions relative to one another in a molecule, as well as the number, type and location of covalent bonds.
A plant genus of the family MENISPERMACEAE. Members contain sinomenine, caffeine, 1,7-dimethylxanthine, and other ALKALOIDS.
Imines are organic compounds containing a functional group with a carbon-nitrogen double bond (=NH or =NR), classified as azomethines, which can be produced from aldehydes or ketones through condensation with ammonia or amines.
Organic compounds that contain GOLD as an integral part of the molecule. Some are used as ANTIRHEUMATIC AGENTS. The term chrysotherapy derives from an ancient Greek term for gold.
The facilitation of a chemical reaction by material (catalyst) that is not consumed by the reaction.
SESQUITERPENES cyclized into two adjoining rings, one being 7-carbons and the other is 5-carbons.
'Ketones' are organic compounds with a specific structure, characterized by a carbonyl group (a carbon double-bonded to an oxygen atom) and two carbon atoms, formed as byproducts when the body breaks down fats for energy due to lack of glucose, often seen in diabetes and starvation states.
A group of compounds consisting in part of two rings sharing one atom (usually a carbon) in common.
A technology, in which sets of reactions for solution or solid-phase synthesis, is used to create molecular libraries for analysis of compounds on a large scale.
Carbonic acid (H2C03). The hypothetical acid of carbon dioxide and water. It exists only in the form of its salts (carbonates), acid salts (hydrogen carbonates), amines (carbamic acid), and acid chlorides (carbonyl chloride). (From Grant & Hackh's Chemical Dictionary, 5th ed)
Thiosemicarbazones are organic compounds resulting from the condensation of thiosemicarbazide with a carbonyl group, characterized by the presence of a -NH-CS-NH-CO- functional structure and widely used in chelation therapy due to their ability to form stable complexes with various metal ions.
Cyclopropanes are a class of hydrocarbons characterized by a small ring structure containing three carbon atoms, each with single bonds to the other two carbons and to hydrogen atoms, making it highly strained and reactive, which has implications for its use as an anesthetic in medicine.
Azo compounds are organic compounds characterized by the presence of one or more azo groups, -N=N-, linking two aromatic rings, which can impart various colors and are used in dyes, pharmaceuticals, and chemical research.
Triazoles are a class of antifungal drugs that contain a triazole ring in their chemical structure and work by inhibiting the synthesis of ergosterol, an essential component of fungal cell membranes, thereby disrupting the integrity and function of the membrane.
Saturated indolizines that are fused six and five-membered rings with a nitrogen atom at the ring fusion. They are biosynthesized in PLANTS by cyclization of a LYSINE coupled to ACETYL COENZYME A. Many of them are naturally occurring ALKALOIDS.
A heavy metal trace element with the atomic symbol Cu, atomic number 29, and atomic weight 63.55.
Organic compounds composed exclusively of carbon and hydrogen forming a closed ring that may be either alicyclic or aromatic.
Alicyclic hydrocarbons in which three or more of the carbon atoms in each molecule are united in a ring structure and each of the ring carbon atoms is joined to two hydrogen atoms or alkyl groups. The simplest members are cyclopropane (C3H6), cyclobutane (C4H8), cyclohexane (C6H12), and derivatives of these such as methylcyclohexane (C6H11CH3). (From Sax, et al., Hawley's Condensed Chemical Dictionary, 11th ed)
The characteristic three-dimensional shape of a molecule.
Substances used for the detection, identification, analysis, etc. of chemical, biological, or pathologic processes or conditions. Indicators are substances that change in physical appearance, e.g., color, at or approaching the endpoint of a chemical titration, e.g., on the passage between acidity and alkalinity. Reagents are substances used for the detection or determination of another substance by chemical or microscopical means, especially analysis. Types of reagents are precipitants, solvents, oxidizers, reducers, fluxes, and colorimetric reagents. (From Grant & Hackh's Chemical Dictionary, 5th ed, p301, p499)
A chemical element having an atomic weight of 106.4, atomic number of 46, and the symbol Pd. It is a white, ductile metal resembling platinum, and following it in abundance and importance of applications. It is used in dentistry in the form of gold, silver, and copper alloys.
Models used experimentally or theoretically to study molecular shape, electronic properties, or interactions; includes analogous molecules, computer-generated graphics, and mechanical structures.
Spectroscopic method of measuring the magnetic moment of elementary particles such as atomic nuclei, protons or electrons. It is employed in clinical applications such as NMR Tomography (MAGNETIC RESONANCE IMAGING).
'Bicyclo compounds' in medicinal chemistry refer to organic molecules containing two fused rings, where each ring shares two common atoms, creating a topological structure that resembles two overlapping circles or bicycle tires.
A group of compounds with an 8-carbon ring. They may be saturated or unsaturated.
A plant genus of the family APOCYNACEAE. It contains ellipticine.
OXADIAZOLES bearing an oxygen at the 5-position. They are mesoionic, with delocalized positive and negative charges.
Ring compounds having atoms other than carbon in their nuclei. (Grant & Hackh's Chemical Dictionary, 5th ed)
Compounds with a 5-membered ring of four carbons and an oxygen. They are aromatic heterocycles. The reduced form is tetrahydrofuran.
Organic compounds that contain the -NCO radical.
Group of alkaloids containing a benzylpyrrole group (derived from TRYPTOPHAN)
A major alkaloid of Vinca minor L., Apocynaceae. It has been used therapeutically as a vasodilator and antihypertensive agent, particularly in cerebrovascular disorders.
'Benzene derivatives' are organic compounds that contain a benzene ring as the core structure, with various functional groups attached to it, and can have diverse chemical properties and uses, including as solvents, intermediates in chemical synthesis, and pharmaceuticals.
Norbornanes are a class of bicyclic organic compounds consisting of a hydrocarbon skeleton made up of two fused 5-membered rings, where five of the six ring carbons are bonded to hydrogens and one is bonded to two additional carbon atoms, forming a bridge between the rings.
Azoles with an OXYGEN and a NITROGEN next to each other at the 1,2 positions, in contrast to OXAZOLES that have nitrogens at the 1,3 positions.

Total synthesis of (+)-nankakurines A and B and (+/-)-5-epi-nankakurine A. (1/73)

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Tyrosine-lipid peroxide adducts from radical termination: para coupling and intramolecular Diels-Alder cyclization. (2/73)

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Interception of a Rautenstrauch intermediate by alkynes for [5+2] cycloaddition: rhodium-catalyzed cycloisomerization of 3-acyloxy-4-ene-1,9-diynes to bicyclo[5.3.0]decatrienes. (3/73)

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Increasing the efficacy of bioorthogonal click reactions for bioconjugation: a comparative study. (4/73)

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The chemical synthesis of tetrodoxin: an ongoing quest. (5/73)

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Detection of transglutaminase activity using click chemistry. (6/73)

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Total synthesis of (+/-)-sorocenol B employing nanoparticle catalysis. (7/73)

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Effects of trehalose polycation end-group functionalization on plasmid DNA uptake and transfection. (8/73)

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A cycloaddition reaction is a type of chemical reaction involving the formation of one or more rings through the coupling of two unsaturated molecules. This process typically involves the simultaneous formation of new sigma bonds, resulting in the creation of a cyclic structure. Cycloaddition reactions are classified based on the number of atoms involved in each component molecule and the number of sigma bonds formed during the reaction. For example, a [2+2] cycloaddition involves two unsaturated molecules, each containing two atoms involved in the reaction, resulting in the formation of a four-membered ring. These reactions play a significant role in organic synthesis and are widely used to construct complex molecular architectures in various fields, including pharmaceuticals, agrochemicals, and materials science.

Cyclization is a chemical process that involves forming a cyclic structure or ring-shaped molecule from a linear or open-chain compound. In the context of medicinal chemistry and drug design, cyclization reactions are often used to synthesize complex molecules, including drugs, by creating rings or fused ring systems within the molecule's structure.

Cyclization can occur through various mechanisms, such as intramolecular nucleophilic substitution, electrophilic addition, or radical reactions. The resulting cyclized compounds may exhibit different chemical and biological properties compared to their linear precursors, making them valuable targets for drug discovery and development.

In some cases, the cyclization process can lead to the formation of stereocenters within the molecule, which can impact its three-dimensional shape and how it interacts with biological targets. Therefore, controlling the stereochemistry during cyclization reactions is crucial in medicinal chemistry to optimize the desired biological activity.

Overall, cyclization plays a significant role in the design and synthesis of many pharmaceutical compounds, enabling the creation of complex structures that can interact specifically with biological targets for therapeutic purposes.

Alkynes are a type of hydrocarbons that contain at least one carbon-carbon triple bond in their molecular structure. The general chemical formula for alkynes is CnH2n-2, where n represents the number of carbon atoms in the molecule.

The simplest and shortest alkyne is ethyne, also known as acetylene, which has two carbon atoms and four hydrogen atoms (C2H2). Ethyne is a gas at room temperature and pressure, and it is commonly used as a fuel in welding torches.

Alkynes are unsaturated hydrocarbons, meaning that they have the potential to undergo chemical reactions that add atoms or groups of atoms to the molecule. In particular, alkynes can be converted into alkenes (hydrocarbons with a carbon-carbon double bond) through a process called partial reduction, or they can be fully reduced to alkanes (hydrocarbons with only single bonds between carbon atoms) through a process called complete reduction.

Alkynes are important intermediates in the chemical industry and are used to produce a wide range of products, including plastics, resins, fibers, and pharmaceuticals. They can be synthesized from other hydrocarbons through various chemical reactions, such as dehydrogenation, oxidative coupling, or metathesis.

Click chemistry is a term used to describe a group of chemical reactions that are fast, high-yielding, and highly selective. These reactions typically involve the formation of covalent bonds between two molecules in a simple and efficient manner, often through the use of a catalyst. The concept of click chemistry was first introduced by K. B. Sharpless, who won the Nobel Prize in Chemistry in 2001 for his work on chiral catalysis.

In the context of medical research and drug development, click chemistry has emerged as a valuable tool for rapidly synthesizing and optimizing small molecule compounds with therapeutic potential. By using click chemistry reactions to quickly and efficiently link different chemical building blocks together, researchers can rapidly generate large libraries of potential drug candidates and then screen them for biological activity. This approach has been used to discover new drugs for a variety of diseases, including cancer, infectious diseases, and neurological disorders.

One common type of click chemistry reaction is the copper-catalyzed azide-alkyne cycloaddition (CuAAC) reaction, which involves the reaction between an azide and an alkyne to form a triazole ring. This reaction is highly selective and can be carried out under mild conditions, making it a popular choice for chemical synthesis in the life sciences. Other types of click chemistry reactions include the Diels-Alder cycloaddition, the thiol-ene reaction, and the Staudinger ligation.

Overall, click chemistry has had a significant impact on medical research and drug development by enabling the rapid and efficient synthesis of complex small molecule compounds with therapeutic potential. Its versatility and selectivity make it a powerful tool for researchers seeking to discover new drugs and better understand the molecular mechanisms underlying human disease.

I'm sorry for any confusion, but "Rhodium" is not a medical term. It is a chemical element with the symbol Rh and atomic number 45. It is a rare, silvery-white, hard, corrosion-resistant, and chemically inert transition metal. It is found in small quantities in platinum or nickel ores along with some other rare metals.

It's primarily used in industrial applications, such as being a key component in catalytic converters in automobiles, which helps to reduce harmful emissions. It's also used in jewelry, electronics, and scientific instruments due to its properties of resistance to corrosion and heat.

If you have any medical terms or concepts that you would like me to explain, please let me know!

Stereoisomerism is a type of isomerism (structural arrangement of atoms) in which molecules have the same molecular formula and sequence of bonded atoms, but differ in the three-dimensional orientation of their atoms in space. This occurs when the molecule contains asymmetric carbon atoms or other rigid structures that prevent free rotation, leading to distinct spatial arrangements of groups of atoms around a central point. Stereoisomers can have different chemical and physical properties, such as optical activity, boiling points, and reactivities, due to differences in their shape and the way they interact with other molecules.

There are two main types of stereoisomerism: enantiomers (mirror-image isomers) and diastereomers (non-mirror-image isomers). Enantiomers are pairs of stereoisomers that are mirror images of each other, but cannot be superimposed on one another. Diastereomers, on the other hand, are non-mirror-image stereoisomers that have different physical and chemical properties.

Stereoisomerism is an important concept in chemistry and biology, as it can affect the biological activity of molecules, such as drugs and natural products. For example, some enantiomers of a drug may be active, while others are inactive or even toxic. Therefore, understanding stereoisomerism is crucial for designing and synthesizing effective and safe drugs.

An azide is a chemical compound that contains the functional group -N=N+=N-, which consists of three nitrogen atoms joined by covalent bonds. In organic chemistry, azides are often used as reagents in various chemical reactions, such as the azide-alkyne cycloaddition (also known as the "click reaction").

In medical terminology, azides may refer to a class of drugs that contain an azido group and are used for their pharmacological effects. For example, sodium nitroprusside is a vasodilator drug that contains an azido group and is used to treat hypertensive emergencies.

However, it's worth noting that azides can also be toxic and potentially explosive under certain conditions, so they must be handled with care in laboratory settings.

Alkadienes are organic compounds that contain two carbon-carbon double bonds in their molecular structure. The term "alka" refers to the presence of hydrocarbons, while "diene" indicates the presence of two double bonds. These compounds can be classified as either conjugated or non-conjugated dienes based on the arrangement of the double bonds.

Conjugated dienes have their double bonds adjacent to each other, separated by a single bond, while non-conjugated dienes have at least one methylene group (-CH2-) separating the double bonds. The presence and positioning of these double bonds can significantly affect the chemical and physical properties of alkadienes, including their reactivity, stability, and spectral characteristics.

Alkadienes are important intermediates in various chemical reactions and have applications in the production of polymers, pharmaceuticals, and other industrial products. However, they can also be produced naturally by some plants and microorganisms as part of their metabolic processes.

Alkenes are unsaturated hydrocarbons that contain at least one carbon-carbon double bond in their molecular structure. The general chemical formula for alkenes is CnH2n, where n represents the number of carbon atoms in the molecule.

The double bond in alkenes can undergo various reactions, such as addition reactions, where different types of molecules can add across the double bond to form new compounds. The relative position of the double bond in the carbon chain and the presence of substituents on the carbon atoms can affect the physical and chemical properties of alkenes.

Alkenes are important industrial chemicals and are used as starting materials for the synthesis of a wide range of products, including plastics, resins, fibers, and other chemicals. They are also found in nature, occurring in some plants and animals, and can be produced by certain types of bacteria through fermentation processes.

Molecular structure, in the context of biochemistry and molecular biology, refers to the arrangement and organization of atoms and chemical bonds within a molecule. It describes the three-dimensional layout of the constituent elements, including their spatial relationships, bond lengths, and angles. Understanding molecular structure is crucial for elucidating the functions and reactivities of biological macromolecules such as proteins, nucleic acids, lipids, and carbohydrates. Various experimental techniques, like X-ray crystallography, nuclear magnetic resonance (NMR) spectroscopy, and cryo-electron microscopy (cryo-EM), are employed to determine molecular structures at atomic resolution, providing valuable insights into their biological roles and potential therapeutic targets.

Sinomenium is not a medical term itself, but it is the name of a plant species (Sinomenium acutum) that has been used in traditional Chinese medicine. The dried root of this plant contains several alkaloids, among which sinomenine is the most prominent and well-studied one.

Sinomenine is an isoquinoline alkaloid with anti-inflammatory, analgesic, and immunomodulatory properties. It has been used in traditional Chinese medicine to treat various conditions such as rheumatoid arthritis, joint pain, and allergies.

In modern medical research, sinomenine has been investigated for its potential therapeutic effects on a range of diseases, including autoimmune disorders, neurodegenerative diseases, and cancer. However, more studies are needed to establish its safety and efficacy in clinical settings.

In the field of organic chemistry, imines are a class of compounds that contain a functional group with the general structure =CR-NR', where C=R and R' can be either alkyl or aryl groups. Imines are also commonly referred to as Schiff bases. They are formed by the condensation of an aldehyde or ketone with a primary amine, resulting in the loss of a molecule of water.

It is important to note that imines do not have a direct medical application, but they can be used as intermediates in the synthesis of various pharmaceuticals and bioactive compounds. Additionally, some imines have been found to exhibit biological activity, such as antimicrobial or anticancer properties. However, these are areas of ongoing research and development.

Organogold compounds are chemical compounds that contain carbon-gold bonds, where gold is bonded directly to carbon atoms. These compounds have been synthesized and studied for their unique properties and potential applications in various fields, including medicine, catalysis, and materials science. In the medical context, organogold compounds have been explored as potential therapeutic agents, particularly in the treatment of cancer and infectious diseases. Some organogold compounds have shown promising antitumor and antibacterial activities, although their clinical use is still under investigation.

Catalysis is the process of increasing the rate of a chemical reaction by adding a substance known as a catalyst, which remains unchanged at the end of the reaction. A catalyst lowers the activation energy required for the reaction to occur, thereby allowing the reaction to proceed more quickly and efficiently. This can be particularly important in biological systems, where enzymes act as catalysts to speed up metabolic reactions that are essential for life.

Sesquiterpenes are a class of terpenes, which are large and diverse group of naturally occurring organic compounds derived from isoprene, a five-carbon molecule. Sesquiterpenes are composed of three isoprene units, making them 15-carbon structures. They are synthesized in plants, fungi, and some insects, and can be found in various essential oils, resins, and other natural products.

Guaiane is a subclass of sesquiterpenes characterized by a particular carbon skeleton structure. Guaiane-type sesquiterpenes contain a unique bicyclic ring system with a five-membered ring fused to a seven-membered ring. This class of compounds includes various natural products, some of which have been found to exhibit biological activities, such as anti-inflammatory, antimicrobial, and cytotoxic effects.

Examples of guaiane sesquiterpenes include:

1. Guaiol: A compound found in the wood of the guaiacum tree, it has been used in traditional medicine for its anti-inflammatory properties.
2. Bulnesin: A compound isolated from the bulnesia sarmientoi tree, it has shown potential as an anticancer agent.
3. Elephantopusin: A compound found in elephantopus mollis, it has been studied for its anti-inflammatory and antioxidant properties.

It is important to note that while these compounds have demonstrated biological activities, further research is necessary to fully understand their mechanisms of action and potential therapeutic applications.

Ketones are organic compounds that contain a carbon atom bound to two oxygen atoms and a central carbon atom bonded to two additional carbon groups through single bonds. In the context of human physiology, ketones are primarily produced as byproducts when the body breaks down fat for energy in a process called ketosis.

Specifically, under conditions of low carbohydrate availability or prolonged fasting, the liver converts fatty acids into ketone bodies, which can then be used as an alternative fuel source for the brain and other organs. The three main types of ketones produced in the human body are acetoacetate, beta-hydroxybutyrate, and acetone.

Elevated levels of ketones in the blood, known as ketonemia, can occur in various medical conditions such as diabetes, starvation, alcoholism, and high-fat/low-carbohydrate diets. While moderate levels of ketosis are generally considered safe, severe ketosis can lead to a life-threatening condition called diabetic ketoacidosis (DKA) in people with diabetes.

"Spiro compounds" are not specifically classified as medical terms, but they are a concept in organic chemistry. However, I can provide a general definition:

Spiro compounds are a type of organic compound that contains two or more rings, which share a single common atom, known as the "spiro center." The name "spiro" comes from the Greek word for "spiral" or "coiled," reflecting the three-dimensional structure of these molecules.

The unique feature of spiro compounds is that they have at least one spiro atom, typically carbon, which is bonded to four other atoms, two of which belong to each ring. This arrangement creates a specific geometry where the rings are positioned at right angles to each other, giving spiro compounds distinctive structural and chemical properties.

While not directly related to medical terminology, understanding spiro compounds can be essential in medicinal chemistry and pharmaceutical research since these molecules often exhibit unique biological activities due to their intricate structures.

Combinatorial chemistry techniques are a group of methods used in the field of chemistry to synthesize and optimize large libraries of chemical compounds in a rapid and efficient manner. These techniques involve the systematic combination of different building blocks, or reagents, in various arrangements to generate a diverse array of molecules. This approach allows chemists to quickly explore a wide chemical space and identify potential lead compounds for drug discovery, materials science, and other applications.

There are several common combinatorial chemistry techniques, including:

1. **Split-Pool Synthesis:** In this method, a large collection of starting materials is divided into smaller groups, and each group undergoes a series of chemical reactions with different reagents. The resulting products from each group are then pooled together and redistributed for additional rounds of reactions. This process creates a vast number of unique compounds through the iterative combination of building blocks.
2. **Parallel Synthesis:** In parallel synthesis, multiple reactions are carried out simultaneously in separate reaction vessels. Each vessel contains a distinct set of starting materials and reagents, allowing for the efficient generation of a series of related compounds. This method is particularly useful when exploring structure-activity relationships (SAR) or optimizing lead compounds.
3. **Encoded Libraries:** To facilitate the rapid identification of active compounds within large libraries, encoded library techniques incorporate unique tags or barcodes into each molecule. These tags allow for the simultaneous synthesis and screening of compounds, as the identity of an active compound can be determined by decoding its corresponding tag.
4. **DNA-Encoded Libraries (DELs):** DELs are a specific type of encoded library that uses DNA molecules to encode and track chemical compounds. In this approach, each unique compound is linked to a distinct DNA sequence, enabling the rapid identification of active compounds through DNA sequencing techniques.
5. **Solid-Phase Synthesis:** This technique involves the attachment of starting materials to a solid support, such as beads or resins, allowing for the stepwise addition of reagents and building blocks. The solid support facilitates easy separation, purification, and screening of compounds, making it an ideal method for combinatorial chemistry applications.

Combinatorial chemistry techniques have revolutionized drug discovery and development by enabling the rapid synthesis, screening, and optimization of large libraries of chemical compounds. These methods continue to play a crucial role in modern medicinal chemistry and materials science research.

Thiosemicarbazones are a class of organic compounds that contain the functional group R-NH-CS-N=CNR', where R and R' are organic radicals. These compounds have been widely studied due to their various biological activities, including antiviral, antibacterial, and anticancer properties. They can form complexes with metal ions, which can also exhibit interesting biological activity. Thiosemicarbazones have the ability to act as chelating agents, forming stable coordination compounds with many metal ions. This property has been exploited in the development of new drugs and diagnostic agents.

Cyclopropanes are a class of organic compounds that contain a cyclic structure consisting of three carbon atoms joined by single bonds, forming a three-membered ring. The strain in the cyclopropane ring is due to the fact that the ideal tetrahedral angle at each carbon atom (109.5 degrees) cannot be achieved in a three-membered ring, leading to significant angular strain.

Cyclopropanes are important in organic chemistry because of their unique reactivity and synthetic utility. They can undergo various reactions, such as ring-opening reactions, that allow for the formation of new carbon-carbon bonds and the synthesis of complex molecules. Cyclopropanes have also been used as anesthetics, although their use in this application has declined due to safety concerns.

Azo compounds are organic compounds characterized by the presence of one or more azo groups (-N=N-) in their molecular structure. The term "azo" is derived from the Greek word "azō," meaning "to boil" or "to sparkle," which refers to the brightly colored nature of many azo compounds.

These compounds are synthesized by the reaction between aromatic amines and nitrous acid or its derivatives, resulting in the formation of diazonium salts, which then react with another aromatic compound containing an active methylene group to form azo compounds.

Azo compounds have diverse applications across various industries, including dyes, pigments, pharmaceuticals, and agrochemicals. They are known for their vibrant colors, making them widely used as colorants in textiles, leather, paper, and food products. In addition, some azo compounds exhibit unique chemical properties, such as solubility, stability, and reactivity, which make them valuable intermediates in the synthesis of various organic compounds.

However, certain azo compounds have been found to pose health risks due to their potential carcinogenicity and mutagenicity. As a result, regulations have been imposed on their use in consumer products, particularly those intended for oral consumption or direct skin contact.

Triazoles are a class of antifungal medications that have broad-spectrum activity against various fungi, including yeasts, molds, and dermatophytes. They work by inhibiting the synthesis of ergosterol, an essential component of fungal cell membranes, leading to increased permeability and disruption of fungal growth. Triazoles are commonly used in both systemic and topical formulations for the treatment of various fungal infections, such as candidiasis, aspergillosis, cryptococcosis, and dermatophytoses. Some examples of triazole antifungals include fluconazole, itraconazole, voriconazole, and posaconazole.

Indolizidines are a type of heterocyclic organic compound that contains a five-membered ring fused to a six-membered ring, with one nitrogen atom and one carbon atom common to both rings. The structure of indolizidine is similar to that of the naturally occurring alkaloids, which are found in various plants and animals and have diverse biological activities.

Indolizidines can be synthesized in the laboratory and have been studied for their potential therapeutic uses, such as anti-inflammatory, antiviral, and insecticidal properties. However, they can also have toxic effects and may interact with other drugs or chemicals in the body.

It is important to note that indolizidines are not a medical term per se, but rather a chemical classification of a specific type of organic compound.

Copper is a chemical element with the symbol Cu (from Latin: *cuprum*) and atomic number 29. It is a soft, malleable, and ductile metal with very high thermal and electrical conductivity. Copper is found as a free element in nature, and it is also a constituent of many minerals such as chalcopyrite and bornite.

In the human body, copper is an essential trace element that plays a role in various physiological processes, including iron metabolism, energy production, antioxidant defense, and connective tissue synthesis. Copper is found in a variety of foods, such as shellfish, nuts, seeds, whole grains, and organ meats. The recommended daily intake of copper for adults is 900 micrograms (mcg) per day.

Copper deficiency can lead to anemia, neutropenia, impaired immune function, and abnormal bone development. Copper toxicity, on the other hand, can cause nausea, vomiting, abdominal pain, diarrhea, and in severe cases, liver damage and neurological symptoms. Therefore, it is important to maintain a balanced copper intake through diet and supplements if necessary.

Cyclic hydrocarbons are a type of organic compounds that contain hydrogen and carbon atoms arranged in ring-like structures. These molecules are characterized by the presence of at least one closed chain of carbon atoms, forming a cycle or ring. The properties and chemical behavior of cyclic hydrocarbons depend on the number of carbon atoms in the ring, the type of bonds between them (single, double, or triple), and the presence of substituents or functional groups attached to the carbon skeleton.

Cyclic hydrocarbons can be classified into two main categories: alicyclic and aromatic compounds. Alicyclic hydrocarbons have only single bonds between the carbon atoms in their rings, while aromatic hydrocarbons contain alternating double bonds that give them unique chemical and physical properties.

Examples of cyclic hydrocarbons include cyclohexane (an alicyclic compound) and benzene (an aromatic compound). These molecules play important roles in various industrial applications, such as fuel production, pharmaceuticals, and materials science. However, some cyclic hydrocarbons can also have harmful effects on human health and the environment, making it essential to handle and dispose of them properly.

Cycloparaffins, also known as naphthenes or cycloalkanes, are a type of hydrocarbon molecule that contain one or more closed rings of carbon atoms. These rings can be saturated, meaning that they contain only single bonds between the carbon atoms, and may also contain one or more alkyl substituents.

The term "cycloparaffin" is used in the context of organic chemistry and petroleum refining to describe a specific class of hydrocarbons. In medical terminology, cycloparaffins are not typically referenced directly, but they may be relevant in certain contexts, such as in discussions of industrial chemicals or environmental exposures.

Cycloparaffins can be found in various sources, including crude oil and natural gas, and they are often used as feedstocks in the production of various chemicals and materials. They are also found in some foods, such as vegetable oils and animal fats, and may be present in trace amounts in some medications or medical devices.

While cycloparaffins themselves are not typically considered to have direct medical relevance, exposure to certain types of cycloparaffins or their derivatives may be associated with various health effects, depending on the level and duration of exposure. For example, some cycloparaffin-derived chemicals have been linked to respiratory irritation, skin and eye irritation, and potential developmental toxicity. However, it is important to note that these effects are typically associated with high levels of exposure in occupational or industrial settings, rather than with normal environmental or dietary exposures.

Molecular conformation, also known as spatial arrangement or configuration, refers to the specific three-dimensional shape and orientation of atoms that make up a molecule. It describes the precise manner in which bonds between atoms are arranged around a molecular framework, taking into account factors such as bond lengths, bond angles, and torsional angles.

Conformational isomers, or conformers, are different spatial arrangements of the same molecule that can interconvert without breaking chemical bonds. These isomers may have varying energies, stability, and reactivity, which can significantly impact a molecule's biological activity and function. Understanding molecular conformation is crucial in fields such as drug design, where small changes in conformation can lead to substantial differences in how a drug interacts with its target.

Indicators and reagents are terms commonly used in the field of clinical chemistry and laboratory medicine. Here are their definitions:

1. Indicator: An indicator is a substance that changes its color or other physical properties in response to a chemical change, such as a change in pH, oxidation-reduction potential, or the presence of a particular ion or molecule. Indicators are often used in laboratory tests to monitor or signal the progress of a reaction or to indicate the end point of a titration. A familiar example is the use of phenolphthalein as a pH indicator in acid-base titrations, which turns pink in basic solutions and colorless in acidic solutions.

2. Reagent: A reagent is a substance that is added to a system (such as a sample or a reaction mixture) to bring about a chemical reaction, test for the presence or absence of a particular component, or measure the concentration of a specific analyte. Reagents are typically chemicals with well-defined and consistent properties, allowing them to be used reliably in analytical procedures. Examples of reagents include enzymes, antibodies, dyes, metal ions, and organic compounds. In laboratory settings, reagents are often prepared and standardized according to strict protocols to ensure their quality and performance in diagnostic tests and research applications.

I'm sorry for the confusion, but "Palladium" is not a medical term. It is a chemical element with symbol Pd and atomic number 46. It is a rare and lustrous silvery-white metal discovered in 1803 by William Hyde Wollaston. It's used in various applications, including jewelry, dental work, electronics, and chemical reactions. If you have any medical terms you would like me to define, please let me know!

Molecular models are three-dimensional representations of molecular structures that are used in the field of molecular biology and chemistry to visualize and understand the spatial arrangement of atoms and bonds within a molecule. These models can be physical or computer-generated and allow researchers to study the shape, size, and behavior of molecules, which is crucial for understanding their function and interactions with other molecules.

Physical molecular models are often made up of balls (representing atoms) connected by rods or sticks (representing bonds). These models can be constructed manually using materials such as plastic or wooden balls and rods, or they can be created using 3D printing technology.

Computer-generated molecular models, on the other hand, are created using specialized software that allows researchers to visualize and manipulate molecular structures in three dimensions. These models can be used to simulate molecular interactions, predict molecular behavior, and design new drugs or chemicals with specific properties. Overall, molecular models play a critical role in advancing our understanding of molecular structures and their functions.

Magnetic Resonance Spectroscopy (MRS) is a non-invasive diagnostic technique that provides information about the biochemical composition of tissues, including their metabolic state. It is often used in conjunction with Magnetic Resonance Imaging (MRI) to analyze various metabolites within body tissues, such as the brain, heart, liver, and muscles.

During MRS, a strong magnetic field, radio waves, and a computer are used to produce detailed images and data about the concentration of specific metabolites in the targeted tissue or organ. This technique can help detect abnormalities related to energy metabolism, neurotransmitter levels, pH balance, and other biochemical processes, which can be useful for diagnosing and monitoring various medical conditions, including cancer, neurological disorders, and metabolic diseases.

There are different types of MRS, such as Proton (^1^H) MRS, Phosphorus-31 (^31^P) MRS, and Carbon-13 (^13^C) MRS, each focusing on specific elements or metabolites within the body. The choice of MRS technique depends on the clinical question being addressed and the type of information needed for diagnosis or monitoring purposes.

Bicyclic compounds are organic molecules that contain two rings in their structure, with at least two common atoms shared between the rings. These compounds can be found in various natural and synthetic substances, including some medications and bioactive molecules. The unique structure of bicyclic compounds can influence their chemical and physical properties, which may impact their biological activity or reactivity.

Cyclooctanes are a class of organic compounds that contain a cyclic octane structure, which is an eight-carbon ring. These molecules can exist in various conformations, including "crowded" or "eclipsed" conformations, where the carbon-hydrogen bonds are arranged in a way that leads to steric strain. This strain makes cyclooctanes less stable than other cycloalkanes, such as cyclohexane. The properties and behavior of cyclooctanes can be studied and applied in fields like chemistry, biochemistry, and materials science.

"Aspidosperma" is a genus of flowering plants in the family Apocynaceae, which are native to the Americas. These trees and shrubs are known for their milky sap and contain various alkaloids with potential medicinal properties. However, it's important to note that many of these compounds can also be toxic if not used properly. Therefore, "Aspidosperma" itself is not a medical term or treatment, but rather a botanical name for a group of plants. Any medicinal use of these plants should be done under the guidance of a qualified healthcare professional.

I'm sorry for any confusion, but "Sydnones" is not a recognized term in medical terminology. It's possible that there may be a misunderstanding or a typo in the term you're looking for. If you meant "Sympathomimetics," these are medications that stimulate the sympathetic nervous system, leading to effects such as increased heart rate, blood pressure, and respiratory rate.

If you had something different in mind or if there's a specific medical concept you'd like me to explain, please provide more details, and I would be happy to help.

Heterocyclic compounds are organic compounds that contain at least one atom within the ring structure, other than carbon, such as nitrogen, oxygen, sulfur or phosphorus. These compounds make up a large class of naturally occurring and synthetic materials, including many drugs, pigments, vitamins, and antibiotics. The presence of the heteroatom in the ring can have significant effects on the physical and chemical properties of the compound, such as its reactivity, stability, and bonding characteristics. Examples of heterocyclic compounds include pyridine, pyrimidine, and furan.

Furans are not a medical term, but a class of organic compounds that contain a four-membered ring with four atoms, usually carbon and oxygen. They can be found in some foods and have been used in the production of certain industrial chemicals. Some furan derivatives have been identified as potentially toxic or carcinogenic, but the effects of exposure to these substances depend on various factors such as the level and duration of exposure.

In a medical context, furans may be mentioned in relation to environmental exposures, food safety, or occupational health. For example, some studies have suggested that high levels of exposure to certain furan compounds may increase the risk of liver damage or cancer. However, more research is needed to fully understand the potential health effects of these substances.

It's worth noting that furans are not a specific medical condition or diagnosis, but rather a class of chemical compounds with potential health implications. If you have concerns about exposure to furans or other environmental chemicals, it's best to consult with a healthcare professional for personalized advice and recommendations.

Isocyanates are a group of highly reactive chemicals that are widely used in the production of flexible and rigid foams, fibers, coatings, and adhesives. The most common isocyanates are toluene diisocyanate (TDI) and methylene diphenyl diisocyanate (MDI). Exposure to isocyanates can cause a range of health effects, including irritation of the eyes, nose, throat, and skin, as well as respiratory symptoms such as coughing, wheezing, and shortness of breath. Long-term exposure has been linked to the development of asthma and other respiratory diseases. Isocyanates are also known to be potential sensitizers, meaning that they can cause an allergic response in some individuals. It is important for workers who handle isocyanates to use appropriate personal protective equipment (PPE) and follow proper safety protocols to minimize exposure.

Indole alkaloids are a type of naturally occurring organic compound that contain an indole structural unit, which is a heterocyclic aromatic ring system consisting of a benzene ring fused to a pyrrole ring. These compounds are produced by various plants and animals as secondary metabolites, and they have diverse biological activities. Some indole alkaloids have important pharmacological properties and are used in medicine as drugs or lead compounds for drug discovery. Examples of medically relevant indole alkaloids include reserpine, which is used to treat hypertension, and vinblastine and vincristine, which are used to treat various types of cancer.

Vincamine is not a medical condition, but rather a type of alkaloid compound that is found in the Vinca minor plant, also known as periwinkle. It is often used in dietary supplements and medications due to its potential cognitive-enhancing and vasodilatory effects.

Medically, vincamine may be used to treat certain conditions related to cerebral insufficiency, which can include symptoms such as memory loss, difficulty concentrating, and dizziness. It works by increasing blood flow to the brain, which can help improve cognitive function and reduce oxidative stress. However, it is important to note that vincamine should only be used under the guidance of a healthcare professional, as it can have potential side effects and interactions with other medications.

Benzene derivatives are chemical compounds that are derived from benzene, which is a simple aromatic hydrocarbon with the molecular formula C6H6. Benzene has a planar, hexagonal ring structure, and its derivatives are formed by replacing one or more of the hydrogen atoms in the benzene molecule with other functional groups.

Benzene derivatives have a wide range of applications in various industries, including pharmaceuticals, dyes, plastics, and explosives. Some common examples of benzene derivatives include toluene, xylene, phenol, aniline, and nitrobenzene. These compounds can have different physical and chemical properties depending on the nature and position of the substituents attached to the benzene ring.

It is important to note that some benzene derivatives are known to be toxic or carcinogenic, and their production, use, and disposal must be carefully regulated to ensure safety and protect public health.

Norbornanes are a class of compounds in organic chemistry that contain a norbornane skeleton, which is a bicyclic structure consisting of two fused cyclohexane rings. One of the rings is saturated, while the other contains a double bond. The name "norbornane" comes from the fact that it is a "nor" (short for "norcarene") derivative of bornane, which has a similar structure but with a methyl group attached to one of the carbon atoms in the saturated ring.

Norbornanes have a variety of applications in organic synthesis and medicinal chemistry. Some derivatives of norbornane have been explored for their potential as drugs, particularly in the areas of central nervous system agents and anti-inflammatory agents. However, there is no specific medical definition associated with "norbornanes" as they are a class of chemical compounds rather than a medical term or condition.

Isoxazoles are not a medical term, but a chemical compound. They are organic compounds containing a five-membered ring consisting of one nitrogen atom, one oxygen atom, and three carbon atoms. Isoxazoles have various applications in the pharmaceutical industry as they can be used to synthesize different drugs. Some isoxazole derivatives have been studied for their potential medicinal properties, such as anti-inflammatory, analgesic, and antipyretic effects. However, isoxazoles themselves are not a medical diagnosis or treatment.

A metal-centered cycloaddition is a subtype of the more general class of cycloaddition reactions. In such reactions "two or ... Cycloaddition reaction Frontier Molecular Orbital Theory Organometallic chemistry Pericyclic reaction 1,3-Dipolar cycloaddition ... Alkylidenes and other carbene analogs participate readily in cycloaddition reactions. Cycloaddition reactions of Ruthenium ... thereby catalyzing the reaction the Diels-Alder reaction. A crucial role of the metal in many cycloadditions reactions is to ...
The Bradsher cycloaddition reaction, also known as the Bradsher cyclization reaction is a form of the Diels-Alder reaction ... The Bradsher cycloaddition was first reported by C. K. Bradsher and T. W. G. Solomons in 1958. C. K. Bradsher, T. W. G. ... II.1The Diels-Alder Reaction". J. Am. Chem. Soc. 80 (4): 933. doi:10.1021/ja01537a045. Merck Index, 14th Ed. C. K. Bradsher, J ...
... cycloaddition reactions involving this class of reaction intermediates. The problem is generally less severe for five-membered ... The high stereospecificity and stereoselectivity inherent in many TMM cycloaddition reactions is a significant advantage; for ... Reactions of diazenes should employ degassed solvents to avoid radical reactions with oxygen. Tetrahydrofuran (THF) at reflux ... reagents which can generate TMM or TMM synthons in situ can be used to effect cycloaddition reactions with appropriate electron ...
The reaction leads to the formation of the same cyclohexene-like structure as usual for a Diels-Alder reaction, but as part of ... In organic chemistry, an intramolecular Diels-Alder cycloaddition is a Diels-Alder reaction in which the diene and a dienophile ... Diels-Alder reaction effects. Intramolecular Diels-Alder cycloaddition is extremely useful for the formation of naturally ... This reaction gives rise to various natural derivatives of decalin. Because the two reacting groups are already attached, two ...
The reaction product of a cycloaddition between diazomethane and trans-diethyl glutaconate is a 1-pyrazoline. This reaction is ... The Diazoalkane 1,3-dipolar cycloaddition is a 1,3-dipolar cycloaddition (an organic reaction) between a 1,3-dipole diazo ... The reaction is also a syn addition, and the configuration in the dipolarophile is preserved. The 1-pyrazoline is unstable and ... With diazo(phenyl)methane as the reactant the regioselectivity is reversed and the reaction is extended even further by simple ...
In organic chemistry, enone-alkene cycloadditions are a version of the [2+2] cycloaddition This reaction involves an enone and ... Enone-alkene cycloadditions often suffer from side reactions, e.g. those associated with the diradical intermediate. These side ... Intramolecular enone-alkene cycloaddition may give either "bent" or "straight" products depending on the reaction ... This energy-wasting process competes with cycloaddition and is evident in reactions that yield mixtures of cis- and trans-fused ...
The Huisgen cycloaddition reaction is a (2+3)cycloaddition. The Nitrone-olefin cycloaddition is a (3+2)cycloaddition. ... In this notation, the DA reaction and the dipolar reaction both become a [4+2]cycloaddition. The reaction between norbornadiene ... The classic example is the reaction of sulfur dioxide with a diene. Other cycloaddition reactions exist: [4+3] cycloadditions ... 3-dipolar cycloaddition is also a [4 + 2]-cycloaddition. Thermal cycloadditions are those cycloadditions where the reactants ...
3-dipolar cycloaddition reaction, also known as the Huisgen cycloaddition or Huisgen reaction. The Huisgen reaction is of ... His major achievement was the development of the 1,3-dipolar cycloaddition reaction, also called the Huisgen cycloaddition. ... Huisgen, Rolf; Grashey, Rudolf; Sauer, Jürgen (1964). "Cycloaddition reactions of alkenes". The Alkenes: Vol. 1 (1964). ... Huisgen, Rolf (1994). The adventure playground of mechanisms and novel reactions. Washington, DC: American Chemical Society. ...
... cycloaddition process. This reaction is a 1,3-dipolar cycloaddition, in which the nitrone acts as the 1,3-dipole, and the ... The nitrone-olefin [3+2] cycloaddition reaction is the combination of a nitrone with an alkene or alkyne to generate an ... These reactions generally take place at much lower temperatures than intermolecular cycloadditions. Regiochemistry is more ... Alkynes can also serve as dipolarophiles in this reaction. The rules for predicting alkene cycloaddition products based on the ...
3-dipolar cycloaddition reaction. The stereoselectivity of 1,3-dipolar cycloaddition reactions between carbonyl ylide dipoles ... 1,3-dipolar cycloaddition with nitrile oxides is a widely used masked-aldol reaction. Cycloaddition between a nitrile oxide and ... Using competition reaction experiments, relative rates of addition for different cycloaddition reactions have been found to ... 3-dipolar cycloaddition reaction with methyl propiolate and methyl propargyl ether. The reaction with methyl propiolate affords ...
Since the initial report of a rhodium-catalyzed VCP [5+2] cycloaddition from Paul A. Wender's research group, other reaction ... Ylijoki KE, Stryker JM (March 2013). "[5 + 2] cycloaddition reactions in organic and natural product synthesis". Chemical ... Vinylcyclopropane [5+2] cycloaddition is a type of cycloaddition between a vinylcyclopropane (VCP) and an olefin or alkyne to ... The proposed reaction mechanism involves an initial [2+2] cycloaddition between the vinylcyclopropane and TCNE, followed by ...
... reaction and [3+2] topochemical ene-azide cycloaddition (TEAC) reaction. The monomers are polymerized by heating for a few days ... synthesized a 2D polymer via 2+2 topochemical cycloaddition reaction.[1] Hema, Kuntrapakam; Ravi, Arthi; Raju, Cijil; Pathan, ... Hema, Kuntrapakam; Sureshan, Kana M. (2019-11-19). "Topochemical Azide-Alkyne Cycloaddition Reaction". Accounts of Chemical ... Hema, Kuntrapakam; Sureshan, Kana M. (2019-11-19). "Topochemical Azide-Alkyne Cycloaddition Reaction". Accounts of Chemical ...
The Prato reaction is a particular example of the well-known 1,3-dipolar cycloaddition of azomethine ylides to olefins. In ... Just as in other fullerene reactions like the Bingel reaction or Diels-Alder reactions this reaction can be reversed. A thermal ... Martín N, Altable M, Filippone S, Martín-Domenech A, Echegoyen L, Cardona CM (2006). "Retro-Cycloaddition Reaction of ... It is known that the Prato reaction is very useful to functionalize endohedral metallofullerenes. Prato reaction on M3N@C80 ...
Photogeneration, rearrangement, and cycloaddition reactions". J. Am. Chem. Soc. 98 (12): 3564-3572. doi:10.1021/ja00428a029. ... was discovered in 1990 by reaction of tetramethyltellurium with xenon difluoride to TeF2(CH3)4 followed by reaction with ... In the Ferrario reaction, phenyl ether is converted to phenoxathiin by action of elemental sulfur and aluminium chloride. ... Certain aromatic thiols can be accessed through a Herz reaction. Disulfides R−S−S−R with a covalent sulfur to sulfur bond are ...
Cycloaddition Reactions in Organic Synthesis. John Wiley & Sons. pp. 187-210. ISBN 9783527301591. Grieco, P. A.; Larsen, S. D ... an exemplar of the Schotten-Baumann reaction first described in the 1880s. The reaction takes place in a two-phase solvent ... It was first produced accidentally by Rudolf Leuckart in the reaction of benzaldehyde with formamide in a process now known as ... The aza-Diels-Alder reaction converts imines and dienes to tetrahydropyridines in which the nitrogen atom can be part of the ...
... s undergo different cycloaddition reactions; coordination properties of phospholes are also well studied. The parent ... One route to phospholes is via the McCormack reaction, involving the addition of a 1,3-diene to a phosphonous chloride (RPCl2) ... For example, they undergo Diels-Alder reactions with electrophilic alkynes. They are basic at P, serving as ligands. 2,5- ... Phenylphospholes can be prepared via zirconacyclopentadienes by reaction with PhPCl2. The behavior of the secondary phospholes ...
I. Synthesis and Cycloaddition Reactions". J. Org. Chem. 35 (10): 3470-3483. doi:10.1021/jo00835a064. Seitz, Karsten; Benecke, ...
... is reactive in cycloaddition reactions. Norbornadiene is also the starting material for the synthesis of ... Norbornadiene is also a useful dienophile in Diels-Alder reactions. Norbornadiene can be formed by a Diels-Alder reaction ... which is a useful source of "chromium tetracarbonyl," e.g. in reactions with phosphine ligands. The norbornadiene analogue of ... The Role of 7-Substituents in Governing the Facial Selectivity for the Diels-Alder Reaction of Benzonorbornadienes with 3,6-Di( ...
Roberts, John D.; Sharts, Clay M. (2011). "Cyclobutane Derivatives from Thermal Cycloaddition Reactions". Organic Reactions. pp ... Owing to the presence of four fluorine substituents, its reactions differ strongly from the behavior of conventional alkenes ... Gozzo, F.; Camaggi, G. (January 1966). "Oxidation reactions of tetrafluoroethylene and their products-I". Tetrahedron. 22 (6): ... Chloroform is fluorinated by reaction with hydrogen fluoride to produce chlorodifluoromethane (R-22). Pyrolysis of ...
Roberts, John D.; Sharts, Clay M. (2011). "Cyclobutane Derivatives from Thermal Cycloaddition Reactions". Organic Reactions. pp ... The reaction is reversible and at room temperature cyclopentadiene dimerizes over the course of hours to re-form ... In accord with the negative values of ΔH° and ΔS° for the Diels-Alder reaction, dissociation of dicyclopentadiene is more ... Cyclopentadiene is a useful diene in Diels-Alder reactions as well as a precursor to metallocenes in organometallic chemistry. ...
Stella, L. (1986). "Captodative Substituent Effects in Cycloaddition Reactions". In Viehe, H. G.; Janousek, Z.; Merényi, R. ( ... Thus, the reaction is slow relative to the R = OCH2CH3 case. When R = CH3, the rate of the reaction is faster relative to when ... Radical reactions play an integral role in several chemical reactions and are also important to the field of polymer science. ... When R = OCH2CH3, the rate of the reaction is the fastest because the reaction has the smallest energy of activation (ΔG‡). The ...
Evans, D. A.; Chapman, K. T.; Bisaha, J. (1984). "New Asymmetric Diels-Alder Cycloaddition Reactions. Chiral α,β-Unsaturated ... including aldol reactions, alkylation reactions, and Diels-Alder reactions. The oxazolidinones are substituted at the 4 and 5 ... utilizes oxazolidinone chiral auxiliaries for one asymmetric alkylation reaction and four asymmetric aldol reactions, setting ... The cycloaddition product was carried forward to the iodolactone shown below, an intermediate in the classic Corey synthesis of ...
This reaction is a derivative of the established Diels-Alder reaction and proceeds via a similar [4+2] cycloaddition mechanism ... The HDDA reaction can be used in a cascade reaction sequence with ene reactions, such as the Alder ene reaction and the ... including reaction solvents. Thus, in practice the HDDA reaction describes a two-step cascade reaction of benzyne formation and ... The simplest model of an HDDA reaction is the cycloaddition of butadiyne and acetylene to form ortho-benzyne (o-benzyne, shown ...
Having obtained silyl enol ether 7 in 11 steps from bicycle 6, itself the product of a Diels-Alder cycloaddition between ... As initially reported by J. M. Conia and P. Le Perchec, the Conia-ene reaction is a heteroatom analog of the ene reaction that ... Like other pericyclic reactions, the original Conia-ene reaction required high temperatures to proceed, limiting its wider ... In the decades after the discovery of the Conia-ene reaction, several improvements allowed for milder reaction conditions and ...
... cycloaddition reactions". Chemical Reviews. 89 (7): 1525-1534. doi:10.1021/cr00097a008. (Name reactions, Cycloadditions). ... Oxo Diels-Alder reaction Aza-Diels-Alder reaction Heintzelman, G. R.; Meigh, I. R.; Mahajan, Y. R.; Weinreb, S. M. (2005). " ... 11) The IDA reaction has been applied to the synthesis of a number of alkaloid natural products. Danishefsky's diene is used to ... The imino Diels-Alder (IDA) reaction may occur either by a concerted or stepwise process. The lowest-energy transition state ...
Bradsher cycloaddition Wagner-Jauregg reaction Imine Diels-Alder reaction Aza-Diels-Alder reaction Diels-Alderases, enzymes ... this reverse reaction is known as the retro-Diels-Alder reaction. The reaction is an example of a concerted pericyclic reaction ... Name reactions, Carbon-carbon bond forming reactions, Ring forming reactions, German inventions, 1928 in science, 1928 in ... Diels-Alder reactions, as concerted cycloadditions, are stereospecific. Stereochemical information of the diene and the ...
Coldham, I.; Hufton, R. (2005). "Intramolecular dipolar cycloaddition reactions of azomethine ylides". Chem. Rev. 105 (7): 2765 ... In this reaction, enoxyphthalimide was used to serve as both the nitrogen and carbon source. The reaction mechanism is proposed ... The reaction mechanism varies with different transition metals. For palladium-catalyzed carboamination reactions, Pd(0)/Pd(II) ... Generally, there are four categories of reaction modes for alkene carboamination. The first class is cyclization reactions, ...
Jewett, John C.; Bertozzi, Carolyn R. (2010-03-22). "Cu-free click cycloaddition reactions in chemical biology". Chemical ... All LSF reactions are chemoselective but not every chemoselective reaction fulfills the requirements of the definition for LSF ... The requirements for LSF can be met by both C-H functionalization reactions and functional group manipulations. LSF reactions ... In contrast, bioorthogonal 1,3-dipolar cycloadditions (see also copper-free click chemistry and Huisgen cycloaddition) ...
... cycloaddition reaction in which three alkyne units (C≡C) react to form a benzene ring. The reaction requires a metal catalyst. ... Carbon-carbon bond forming reactions, Cycloadditions, Multiple component reactions). ... Being a cycloaddition reaction, it has high atom economy. Many variations have been developed, including cyclisation of ... Wills, M. S. B.; Danheiser, R. L. (1998). "Intramolecular [4 + 2] Cycloaddition Reactions of Conjugated Ynones. Formation of ...
Both isomers participate in Kumada coupling reactions. trans-1,2-Dichloroethylene participates in cycloaddition reactions. ... "Arene synthesis by extrusion reaction. 16. Coplanar and stable derivatives of 13,14-didehydro-tribenzo[a,c,e]cyclooctene: ...
A metal-centered cycloaddition is a subtype of the more general class of cycloaddition reactions. In such reactions "two or ... Cycloaddition reaction Frontier Molecular Orbital Theory Organometallic chemistry Pericyclic reaction 1,3-Dipolar cycloaddition ... Alkylidenes and other carbene analogs participate readily in cycloaddition reactions. Cycloaddition reactions of Ruthenium ... thereby catalyzing the reaction the Diels-Alder reaction. A crucial role of the metal in many cycloadditions reactions is to ...
... photochemical cycloaddition reaction. A Bronsted acid catalyzed rearrangement of the 11-trimethylsilyl-tetracyclo[8.1.0.03,7.04 ... cycloaddition, followed by a novel radical cyclization with a cyclic conjugated diene, in only five steps. A novel [4+1] ... 1. Chromium(0)- Promoted Higher Order Cycloaddition Reactions: Studies Toward The Total Synthesis Of The Cyclocitrinols And ... De, Saptarshi, "1. Chromium(0)- Promoted Higher Order Cycloaddition Reactions: Studies Toward The Total Synthesis Of The ...
This new tandem reaction comprises a cycloaddition between a nitrile and (TMS)N-3 followed by an intramolecular N-allylation. ... Synthesis of fused tetrazole derivatives via a tandem cycloaddition and N-allylation reaction and parallel synthesis of fused ... Synthesis of fused tetrazole derivatives via a tandem cycloaddition and N-allylation reaction and parallel synthesis of fused ... the synthesis of novel fused tricyclic tetrazoles from allylic bromides generated by the recently discovered DiazAll reaction ...
This thesis introduces the total syntheses of C-glycosides by starting with two cycloaddition reactions. The [4+2] reaction of ... The [4+3] cycloaddition of furan and pentachloroacetone and subsequent reactions provided C-furanosides and C-pyranosides. A ... 1,3-pentadiene with glyoxylic acid and subsequent reactions afforded five C-pyranosides. ... This thesis introduces the total syntheses of C-glycosides by starting with two cycloaddition reactions. The [4+2] reaction of ...
Keywords: Activity-based protein profiling; Cycloaddition reaction; Lipases; Lipid esterases; Tetrahydrolipstatin. MeSH terms * ... Here, we used THL analogs functionalized to enable Huisgen-base cycloaddition, commonly known as "click chemistry," to identify ...
The examination of the cycloaddition reactions of 1 1 2 3. The examination of the cycloaddition reactions of 1 1 2 3 17 bearing ... Number 1 Previous studies with 1 2 3 Perhaps the most remarkable of the cycloaddition reactions of 1 1 2 3 and the most ... Herein we display that while such substituents do slow the pace of reaction of the 1 2 3 their reaction with amidines remained ... rapid rates of cycloaddition.11 Recently our attempts extended to 1 1 2 3 examining the synthesis and cycloaddition reaction ...
This review offers a systematic analysis of literature data about intramolecular C-H insertion reactions of diazocarbonyl ... Recent progress in the synthesis of nitroisoxazoles and their hydrogenated analogs via [3+2] cycloaddition reactions ( ... The key diazo ester 70 was obtained in a Leimgruber-Batcho reaction from 3-methyl-4-nitrophenol. The reaction of compound 70 ... had a substantial effect on the reaction (Scheme 20). The reaction catalyzed by Rh2(OAc)4 produced a significant amount of ...
Density functional theory calculations were used to investigate the reaction mechanisms on [3 + 2] cycloaddition reactions of ... cycloaddition reaction. All of these findings could be useful for experimental chemists to develop "click reactions" in ... Home » Reaction Mechanisms on [3 + 2] Cycloaddition of Azides with Metal Carbyne Complexes: Significant Effects of Aromaticity ... Reaction Mechanisms on [3 + 2] Cycloaddition of Azides with Metal Carbyne Complexes: Significant Effects of Aromaticity, ...
... as diene in thermal DielsAlder cycloaddition reactions with several electron-poor dienophiles is reported. Among several ... Reactivity of 4-Vinyl-2H-1-benzopyran-2-ones in Diels-Alder Cycloaddition Reactions: Access to Coumarin-Based Polycycles with ... Reactivity of 4-Vinyl-2H-1-benzopyran-2-ones in Diels-Alder Cycloaddition Reactions: Access to Coumarin-Based Polycycles with ... as diene in thermal DielsAlder cycloaddition reactions with several electron-poor dienophiles is reported. Among several ...
The influence of reaction conditions on the outcome of the cycloadditions, in particular the stereoselectivity and reaction ... While the cycloadditions have been attempted at the sulfide, sulfoxide and sulfone levels of oxidation, use of the sulfoxide ... The Diels-Alder cycloadditions of cyclopentadiene and 2,3-dimethyl-1,3-butadiene to a range of 2-thio-3-chloroacrylamides under ... The influence of reaction conditions on the outcome of the cycloadditions, in particular the stereoselectivity and reaction ...
3 (Cyclo)addition Reactions with Styrenes. 4 Transformations via Cleavage of C-F, C-I, C-S and C-N Bonds ... Photoinduced Organic Reactions by Employing Pyrene Catalysts. Akira Shiozuka. a Interdisciplinary Graduate School of ... Cycloadditions - Established and Novel Trends - in Celebration of the 70th Anniversary of the Nobel Prize Awarded to Otto Diels ... pyrene - photoinduced reactions - organic photosensitizer - electron transfer - organic synthesis Publication History. Received ...
First diastereoselective [3+2] cycloaddition reaction of diethyl isocyanomethylphosphonate and maleimides. Organic and ...
Soluble imidazolium-functionalized coordination cages for efficient homogeneous catalysis of CO 2 cycloaddition reactions. ... Hydration reactions catalyzed by transition metal-NHC (NHC = N-heterocyclic carbene) complexes. Coordination Chemistry Reviews ... Probing Reaction Mechanism of [1,5]‐Migration in Pyrrolium and Pyrrole Derivatives: Activation of a Stronger Bond in ... Mild Friedel-Crafts Reactions inside a Hexameric Resorcinarene Capsule: C−Cl Bond Activation through Hydrogen Bonding to ...
Recorded Lecture Topic: Topochemical Azide-Alkyne Cycloaddition (TAAC) reaction for the synthesis of biopolymer mimics ... Recorded Lecture Topic: In situ cycloaddition for the development of small molecule drugs ...
Danese, M.; Bon, M.; Piccini, G. M.; Passerone, D. The reaction mechanism of the azide-alkyne Huisgen cycloaddition. Phys. Chem ... Manipulating the reaction path of the CO2 hydrogenation reaction in molecular sieves. Catal. Sci. Technol. 2015, 5 (9), 4613- ... magnetically recoverable and reusable catalysts for Suzuki CC cross-coupling reactions, hydrogenation, and sequential reactions ... A nearly zero-strain Li-rich rock-salt oxide with multielectron redox reactions as a cathode for Li-ion batteries. Chem. Mater. ...
Title: Asymmetric Conjugate Addition and Cycloaddition Reactions to α,β-Unsaturated 2-Acyl Imidazoles ... Title: Asymmetric Alkynylation and Propargylation Reactions Catalyzed by Chiral Copper Complexes.. Supervisors: Prof. Vinod K. ... Title: Asymmetric Organocatalytic Reactions Catalyzed by a Cinchonidine Derived Squaramide Catalyst. Supervisors: Prof. V. K. ... Title: Development of Ruthenium Catalyzed Cross-Coupling Reactions and their Applications in Total Syntheses of Hydroxy _β_- ...
ICCROS 2024: Cycloaddition Reactions in Organic Synthesis Conference, Toronto (Jun 13-14, 2024) ... ICCROS 2024: Cycloaddition Reactions in Organic Synthesis Conference, Berlin (Jul 22-23, 2024) ...
FISCHER-CARBENE-COMPLEXES/AMINO-ACID DERIVATIVES/CYCLOADDITION REACTIONS/ALLYLIC SUBSTITUTION ... ... TRANSITION-METAL CATALYSIS/CROSS-COUPLING REACTION/PAUSON-KHAND REACTION/ZINC-ENE REACTIONS/ALLYLIC ACETATES ... . Tamaru, in ... Pauson-Khand reactions catalyzed by entrapped rhodium complexes. ... Organic Chemistry Portal Pauson-Khand reactions catalyzed ... Iridium-catalyzed enantioselective Pauson-Khand-type reaction of 1,6-enynes. ... , Enynes, Carbonylation, Pauson-Khand reaction ...
Tandem Ring Opening/Intramolecular [2 + 2] Cycloaddition Reaction for the Synthesis of Cyclobutane Fused Thiazolino-2-Pyridones ... Intramolecular Povarov Reactions for the Synthesis of Chromenopyridine fused 2-Pyridone Polyheterocycles Binding to α-Synuclein ...
This reaction precedes rapidly via an inverse electron demand [4 + 2] Diels-Alder cycloaddition to yield a stable covalent ... Cu-free cycloadditions offer efficient ligation reactions useful for a variety of bioconjugation applications. When working ... The most well-known example of a "click" reaction is the Copper(I)-catalyzed Azide-Alkyne 1,3-dipolar Cycloaddition (CuAAC), ... The reaction of 1,2,4,5 tetrazines with strained alkenes has been applied as a rapid bio-orthogonal click chemistry reaction ...
At the heart of click chemistry is the Huisgen cycloaddition reaction between alkyne and azide. The reason the click reaction ... On reaction with iodine and oxidant, the tin-aryl bond is cleaved. The residual unreacted starting material can be separated ... Click for PET: rapid preparation of [18F]fluoropeptides using CuI catalyzed 1,3-dipolar cycloaddition. Tetrahedron Lett. 2006; ... A stepwise huisgen cycloaddition process: copper(I)-catalyzed regioselective "ligation" of azides and terminal alkynes. Angew ...
Microwave assisted cycloaddition reactions of thieno[3,4-d]pyridazinone and thieno[3,4-c]quinolinone. Heterocycles 2008, 75, ... Using the same reagent ratios and solvent as these for the reaction run at room temperature, we performed the reaction of ... The build-up of pressure in the closed reaction vessel was carefully monitored. After the irradiation, the reaction tube was ... The build-up of pressure in the closed reaction vessel was carefully monitored. After the irradiation, the reaction tube was ...
Two new methanofullerenes (PC61BP & HC61NP) have been synthesized by using our reported amine assisted cycloaddition reaction ( ... Two new methanofullerenes (PC61BP & HC61NP) have been synthesized by using our reported amine assisted cycloaddition reaction ( ...
The second key design feature is a one pot oxidative dearomatization/Diels-Alder cycloaddition reaction (6→5). Resorcinol ... Because of the compact tetracyclic cage the route is built around many unusual reaction observations and solutions have emerged ... For example a first of its kind Grob fragmentation reaction featuring a trifluoroethyl leaving group has been uncovered ... whose Carboplatin purpose is to guideline the oxidative dearomatization reaction towards Carboplatin allylic ether site. ...
Our research interests are centered on a very reliable organic reaction - the copper-catalyzed cycloaddition of sulfonyl azides ...
cycloadditions as a strategy.19 Later, novel approaches were also and potent catalyst for various organic reactions.2 Moreover ... Reactions in Aqueous Media, Wiley & Sons, New York, 1997. 6 (a) D. C. Rideout and R. Breslow, J. Am. Chem. Soc., 1980, 102, ... 2). Similarly, reactions of 1,3-cyclohexanedione (1), 5-isopropyl- 1,3-cyclohexanedione (3), 5-phenyl-1,3-cyclohexanedione (4 ... good yields by the reactions of a variety of cyclic 1,3-dicarbonyls with several a,b-unsaturated ...
A group of Spanish scientists have investigated the intramolecular [4C+3C] cycloaddition reaction of allenedienes in this ... Reactions of an organoruthenium anticancer complex with 2-mercaptobenzanilide-a model for the active-site cysteine of protein ... Theoretical study on intramolecular allene-diene cycloadditions catalyzed by PtCl2 and Au(I) complexes. Sergi Montserrat, Isaac ... do the allene substituents affect the reaction mechanism? Are the PtCl2 and Au(I)-catalyzed processes exhibiting a similar ...
... of anchored dyes on mesoporous metal oxide photoelectrochemical cells with copper-free Huisgen cycloaddition reaction. Y. ... Photoinduced Electron-Transfer Reactions of Perylene in Acetonitrile. E. Vauthey, P. Suppan, E. Haselbach and R.S. Davidson. ... Entropic effects in excited state CT reactions. A. Pigliucci, E. Vauthey and W. Rettig. Chemical Physics Letters, 469 , 2009, ... Photoinduced electron transfer reactions: from the elucidation of old problems towards the exploration of interfaces. M. ...
... biotinylation reagent that reacts with TCO-containing compounds via a Inverse-Electron-Demand Diels-Alder reaction to form a ... The inverse-electron demand Diels-Alder cycloaddition reaction of TCO with tetrazines is a bioorthogonal reaction that ... Such excellent reaction rate constants are unparalleled by any other bioorthogonal reaction pair described to date. ... biotinylation reagent that reacts with TCO-containing compounds via a Inverse-Electron-Demand Diels-Alder reaction to form a ...
Diels-Alderases (DAs), functionally unique enzymes catalysing [4 + 2] cycloaddition reactions, have received considerable ... which catalyses the oxidative cyclisation reactions of isoprenoid-substituted phenolic compounds." Find the paper and authors ...
  • Metal ions are frequently a component of 1,3-dipolar cycloadditions, and Diels-Alder reactions. (wikipedia.org)
  • A Lewis acidic can coerce a Diene into the reactive cisoid conformation, thereby catalyzing the reaction the Diels-Alder reaction. (wikipedia.org)
  • Cycloaddition reaction Frontier Molecular Orbital Theory Organometallic chemistry Pericyclic reaction 1,3-Dipolar cycloaddition Diels-Alder reaction Cram, Donald J. (1964). (wikipedia.org)
  • Whereas the Diels-Alder type reactions (which are 2+4) occur very easily. (chemistry-online.com)
  • But if we test these reactions with some of the reactants in their excited state (photochemical reactions), the opposite happens, i.e., now the 2+2 or 4+4 reactions occur easily while the Diels-Alder reaction in the excited state is very difficult to observe. (chemistry-online.com)
  • Since we have another π system with 4 electrons the Diels-Alder reaction will be π 2s +π 4s , a reaction involving both π systems in a suprafacial manner, and this has importance, since the stereochemistry of the interaction implies stereochemistry in the products, since in our case it will cause the b substituents to go up and the to substituents to go down. (chemistry-online.com)
  • The Diels-Alder cycloadditions of cyclopentadiene and 2,3-dimethyl-1,3-butadiene to a range of 2-thio-3-chloroacrylamides under thermal, catalytic and microwave conditions is described. (ucc.ie)
  • While the cycloadditions have been attempted at the sulfide, sulfoxide and sulfone levels of oxidation, use of the sulfoxide derivatives is clearly beneficial for stereoselective construction of Diels-Alder cycloadducts. (ucc.ie)
  • 1. Chromium(0)- Promoted Higher Order Cycloaddition Reactions: Studies Toward The Total Synthesis Of The Cyclocitrinols And Echinopines A And B 2. (wayne.edu)
  • A molecular electron density theory study of the higher-order cycloaddition reactions of tropone with electron-rich ethylenes. (unab.cl)
  • Dive into the research topics of 'A molecular electron density theory study of the higher-order cycloaddition reactions of tropone with electron-rich ethylenes. (unab.cl)
  • This new tandem reaction comprises a cycloaddition between a nitrile and (TMS)N-3 followed by an intramolecular N-allylation. (lu.se)
  • This review offers a systematic analysis of literature data about intramolecular C-H insertion reactions of diazocarbonyl compounds, applicable to the synthesis of biologically active nitrogen- and oxygen-containing heterocyclic systems. (springer.com)
  • Intramolecular insertion reactions at C-H bonds have the highest synthetic importance, while only a few cases are known for intermolecular reactions of this type. (springer.com)
  • Here, we used THL analogs functionalized to enable Huisgen-base cycloaddition, commonly known as "click chemistry," to identify target proteins after enrichment from mycobacterial cell lysates obtained from different physiological conditions. (nih.gov)
  • We then used Huisgen cycloaddition chemistry (or Click-Chemistry) to identify protein disulfide isomerase (PDI) as the molecular target of multiple active compounds. (gobreastcancer.info)
  • Click chemistry is a term coined by Barry Sharpless to describe chemical reactions that are modular, efficient, wide in scope, provide very high yields, and generate only inoffensive byproducts. (sigmaaldrich.com)
  • Cycloadditions involving metal centers are a staple of organic and organometallic chemistry, and are involved in many industrially-valuable synthetic processes. (wikipedia.org)
  • It was expected that this modification would decrease the overall reactivity of the 1 2 3 perhaps even to the point of preventing the anticipated cycloaddition chemistry. (researchassistantresume.com)
  • All of these findings could be useful for experimental chemists to develop "click reactions" in organometallic chemistry. (chem8.org)
  • Alkylidenes and other carbene analogs participate readily in cycloaddition reactions. (wikipedia.org)
  • This review is dedicated to carbenoid reactions at С-Н bonds as key steps in the total synthesis of some natural compounds and their synthetic analogs, characterized by a broad range of biological activity. (springer.com)
  • Such C-H insertion reactions are the key steps in many syntheses of heterocyclic systems, analogs of natural compounds. (springer.com)
  • Three previously unreported 1 2 3 were chosen to probe the effects of electron-donating substituents within the reactivity and regioselectivity of the cycloaddition reactions with amidines ynamines and enamines. (researchassistantresume.com)
  • The reactivity of 4-(1-butoxyvinyl)-2H-chromen-2-one (1) and (E)-4-(2-butoxyvinyl)-2H-chromen-2-one (2) as diene in thermal DielsAlder cycloaddition reactions with several electron-poor dienophiles is reported. (univ-lorraine.fr)
  • Density functional theory calculations were used to investigate the reaction mechanisms on [3 + 2] cycloaddition reactions of azides with metal carbyne complexes. (chem8.org)
  • This reaction between azides and alkynes offers high yields and involves functionalities that can be introduced relatively easily in a variety of molecules such as synthetic polymers, fluorophores, small molecules or into specific locations in biomolecules. (sigmaaldrich.com)
  • Our PEG azides are ideal starting materials for the synthesis of PEG derivatives via azide-alkyne cycloaddition or Staudinger ligation. (sigmaaldrich.com)
  • The interaction of that π system of 2 electrons is with both ends on the same side and is represented by first indicating whether the electrons involved in the reaction are π or s , in this case both are of π type, then we indicate the number of electrons, in this case 2, and finally the stereochemistry, in the suprafacial example, so the system would be π 2s . (chemistry-online.com)
  • The key structural unit, the bicyclo[4.4.1]A/B ring system, was constructed by a regioselective Cr(0)-promoted [6π + 4π] photochemical cycloaddition reaction. (wayne.edu)
  • The key [5.5.7] tricyclic intermediate, which has been previously used for synthesis of Echinopine A and B, was synthesized using a sequence of Cr(0)-promoted photochemical [6p+2p] cycloaddition, followed by a novel radical cyclization with a cyclic conjugated diene, in only five steps. (wayne.edu)
  • Cycloaddition reactions of Ruthenium phosphinidenes with alkenes and alkynes is an active area research and has promise as catalytic cycle for hydrophosphination. (wikipedia.org)
  • They can be formed as ligands in-situ by the [2+2] cycloaddition of sterically bulky alkynes bound to a metal. (wikipedia.org)
  • The Dötz reaction is a formal [3+2+1] cycloaddition of two alkynes, a carbene, and a carbonyl ligand to form a benzene ring. (wikipedia.org)
  • Pérez-Ramírez, J. Reaction-induced metal-metal oxide interactions in Pd-In 2 O 3 /ZrO 2 catalysts drive selective and stable CO 2 hydrogenation to methanol. (empa.ch)
  • A common role for a metal centre in cycloaddition reactions is to exert control over the conformation of the reactants. (wikipedia.org)
  • A crucial role of the metal in many cycloadditions reactions is to bind simultaneously to the reactants. (wikipedia.org)
  • Underlying any attempt to explain cycloaddition reactions is Frontier Molecular Orbital Theory, which describes the interaction between the Highest Occupied Molecular Orbital (HOMO) and the Lowest Unoccupied Molecular Orbital (LUMO) of the reactants. (wikipedia.org)
  • These arrows indicate the movement of electron pairs from the reactants to move to the TS, and subsequently to the product of the reaction. (chemistry-online.com)
  • Among the best known dipoles used in 1,3-dipolar reactions are O 3 , NO 2 , CON (nitrile oxide), COO (carbonyl oxide). (chemistry-online.com)
  • This reaction would be a case of a 2+2 reaction, since one of the components has two electrons and the other also has two electrons. (chemistry-online.com)
  • Within the cycloaddition reactions it is worth highlighting the existence of some reactions that are widely used in heterocycle synthesis since they occur very easily, and they are the 1,3-dipolar cycloaddition reactions which is the reaction between a 2-electron π system with a 1,3-dipole which is a system with 4 electrons and three centers (which can usually be represented by different resonant forms). (chemistry-online.com)
  • Cycloadditions that require unstable synthons such as carbanions or carbenes are often possible using organometallic compounds. (wikipedia.org)
  • Several synthetic routes to cyclopropyl and cyclopropenyl compounds involve the cycloaddition of a metal carbene to an alkene or alkyne. (wikipedia.org)
  • A method for the synthesis of novel fused tricyclic tetrazoles from allylic bromides generated by the recently discovered DiazAll reaction has been developed. (lu.se)
  • The unusual reaction of carbene insertion at hydrocarbon C-H bonds was discovered a half-century ago and attracted considerable interest due to its potential for building new С-С bonds. (springer.com)
  • AGENT Recent Advances in Catalytic Asymmetric Reactions Promoted by Transition Metal Complexes. (organic-chemistry.org)
  • Another example is ethylene plus butadiene to give cyclohexene, this would be a 2+4 reaction. (chemistry-online.com)
  • But which is a very unstable compound that breaks down in a reverse cycloaddition reaction but instead of generating the starting products, it breaks down in such a way as to give, on the one hand, a carbonyl group and, on the other hand, carbonyl oxide. (chemistry-online.com)
  • Metal-stabilized allyl and pentadienyl complexes are used in [4+3] and [5+2] cycloadditions for preparing seven-membered rings. (wikipedia.org)
  • Whether that movement is to the right or left is completely arbitrary and only gives us an idea of how the electron pairs can be redistributed, but the only true thing is that in the TS the π electron pairs involved in the reaction form a closed loop. (chemistry-online.com)
  • The examination of the cycloaddition reactions of 1 1 2 3 17 bearing electron-donating substituents at C5 are described. (researchassistantresume.com)
  • The effectiveness and robust nature of these reactions led to our further study of 1 1 2 3 that contain electron-donating organizations at C5. (researchassistantresume.com)
  • Further analyses show that the electron-donating ligand on metal centers or the electron-withdrawing group on the azide could accelerate the [3 + 2] cycloaddition reaction. (chem8.org)
  • In this review, we summarize recent developments in pyrene-catalyzed photoinduced organic reactions occurring via energy transfer or single-electron transfer based on the excited state of the pyrene. (thieme-connect.com)
  • Herein we display that while such substituents do slow the pace of reaction of the 1 2 3 their reaction with amidines remained remarkably effective providing the product pyrimidines in superb yields. (researchassistantresume.com)
  • In selected cases even less effective dienophiles such as ynamines and enamines were found to be capable of cycloaddition albeit in more modest yields. (researchassistantresume.com)
  • The most well-known example of a "click" reaction is the Copper(I)-catalyzed Azide-Alkyne 1,3-dipolar Cycloaddition (CuAAC), which yields a 1,4-disubstituted five-membered 1,2,3-triazole ring. (sigmaaldrich.com)
  • For example, olefin metathesis using a Grubbs catalyst typically involves a reversible [2+2] cycloaddition. (wikipedia.org)
  • Its exact nature involves two double bonds, indicating its potential for reactions. (lookchem.com)
  • An unusual formal [5+4] cycloaddition was reported by Kreiter et al. (wikipedia.org)
  • In such reactions "two or more unsaturated molecules unite directly to form a ring", incorporating a metal bonded to one or more of the molecules. (wikipedia.org)
  • Metals play a crucial role in cycloaddition reactions because they can bind to unsaturated molecules, changing the symmetries and energy levels of the HOMO and/or LUMO. (wikipedia.org)
  • An advantage of this reaction for biological purposes is that the azide and alkyne functional groups are largely inert, or biorthogonal, towards biological molecules and aqueous environments. (sigmaaldrich.com)
  • However, this review is not meant to be comprehensive and can provide only a general view of the synthetic potential of such reactions. (springer.com)
  • A metal-centered cycloaddition is a subtype of the more general class of cycloaddition reactions. (wikipedia.org)
  • There are two general types of metal-centered cycloaddition reactions: those in which the metal is incorporated into the cycle (a metallocycle), and those in which the metal is external to the cycle. (wikipedia.org)
  • Aromaticity plays an important role in stabilizing the products in these reactions. (chem8.org)
  • The Woodward-Hoffmann rules and Green-Davies-Mingos rules can provide some indication of the effects of metal-bonding on cycloaddition reactions. (wikipedia.org)
  • The influence of reaction conditions on the outcome of the cycloadditions, in particular the stereoselectivity and reaction efficiency, is discussed. (ucc.ie)
  • A cycloaddition will only proceed if the HOMO and LUMO have an allowed symmetry and are similar in energy. (wikipedia.org)
  • Number 1 Previous studies with 1 2 3 Perhaps the most remarkable of the cycloaddition reactions of 1 1 2 3 and the most effective of those examined to date is definitely their reactions with amidines to provide pyrimidines. (researchassistantresume.com)
  • These reactions are 2+4, to give rise to 5-membered cyclic systems. (chemistry-online.com)
  • Thus, in the case of ozonolysis, O 3 reacts very easily with olefinic systems, where it is postulated that this is the first product of the reaction. (chemistry-online.com)
  • When one of the components of the cycloaddition reaction, or one of the π-systems, intervenes in the reaction with both ends of its π-system on the same side, it is said to proceed in a supra-facial manner. (chemistry-online.com)