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Solid-phase Synthesis
In chemistry, solid-phase synthesis is a method in which molecules are covalently bound on a solid support material and synthesised step-by-step in a single reaction vessel utilising selective protecting group chemistry. Benefits compared with normal synthesis in a liquid state include: * High efficiency and throughput * Increased simplicity and speed The reaction can be driven to completion and high yields through the use of excess reagent. In this method, building blocks are protected at all reactive functional groups. The order of functional group reactions can be controlled by the order of deprotection. This method is used for the synthesis of peptides, deoxyribonucleic acid ( DNA), ribonucleic acid (RNA), and other molecules that need to be synthesised in a certain alignment. More recently, this method has also been used in combinatorial chemistry and other synthetic applications. The process was originally developed in the 1950s and 1960s by Robert Bruce Merrifield in or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Chemistry
Chemistry is the scientific study of the properties and behavior of matter. It is a natural science that covers the elements that make up matter to the compounds made of atoms, molecules and ions: their composition, structure, properties, behavior and the changes they undergo during a reaction with other substances. Chemistry also addresses the nature of chemical bonds in chemical compounds. In the scope of its subject, chemistry occupies an intermediate position between physics and biology. It is sometimes called the central science because it provides a foundation for understanding both basic and applied scientific disciplines at a fundamental level. For example, chemistry explains aspects of plant growth ( botany), the formation of igneous rocks ( geology), how atmospheric ozone is formed and how environmental pollutants are degraded ( ecology), the properties of the soil on the moon ( cosmochemistry), how medications work (pharmacology), and how to collect DNA ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Carbonyl Group
In organic chemistry, a carbonyl group is a functional group composed of a carbon atom double-bonded to an oxygen atom: C=O. It is common to several classes of organic compounds, as part of many larger functional groups. A compound containing a carbonyl group is often referred to as a carbonyl compound. The term carbonyl can also refer to carbon monoxide as a ligand in an inorganic or organometallic complex (a metal carbonyl, e.g. nickel carbonyl). The remainder of this article concerns itself with the organic chemistry definition of carbonyl, where carbon and oxygen share a double bond. Carbonyl compounds In organic chemistry, a carbonyl group characterizes the following types of compounds: Other organic carbonyls are urea and the carbamates, the derivatives of acyl chlorides chloroformates and phosgene, carbonate esters, thioesters, lactones, lactams, hydroxamates, and isocyanates. Examples of inorganic carbonyl compounds are carbon dioxide and carbonyl sulfide. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Noncovalent Solid-phase Organic Synthesis
Noncovalent solid-phase organic synthesis or NC-SPOS is a form of Solid-phase synthesis whereby the organic substrate is bonded to the solid phase not by a covalent bond but by other chemical interactions. This bond may consist of an induced dipole interaction between a hydrophobic matrix and a hydrophobic anchor. As long as the reaction medium is hydrophilic (polar) in nature the anchor will remain on the solid phase. Switching to a nonpolar solvent releases the organic substrate containing the anchor. In one experimental setup the hydrophobic matrix is RP silica gel (C18) and the anchor is acridone. Acridone is N-alkylated and the terminal alkene group is converted into an aldehyde by ozonolysis. This compound is bonded to RP silica gel and this system is subjected to a tandem sequence of organic reactions. The first reaction is a Barbier reaction with propargylic bromide in water (green chemistry) and the second reaction is a Sonogashira coupling. Substrates may vary in thes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Combinatorial Chemistry
Combinatorial chemistry comprises chemical synthetic methods that make it possible to prepare a large number (tens to thousands or even millions) of compounds in a single process. These compound libraries can be made as mixtures, sets of individual compounds or chemical structures generated by computer software. Combinatorial chemistry can be used for the synthesis of small molecules and for peptides. Strategies that allow identification of useful components of the libraries are also part of combinatorial chemistry. The methods used in combinatorial chemistry are applied outside chemistry, too. History Combinatorial chemistry had been invented by Furka Á (Eötvös Loránd University Budapest Hungary) who described the principle of it, the combinatorial synthesis and a deconvolution procedure in a document that was notarized in 1982.Furka Á. Tanulmány, gyógyászatilag hasznosítható peptidek szisztematikus felkutatásának lehetőségéről (and Study on the possibility of sys ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Oligonucleotide Synthesis
Oligonucleotide synthesis is the chemical synthesis of relatively short fragments of nucleic acids with defined chemical structure ( sequence). The technique is extremely useful in current laboratory practice because it provides a rapid and inexpensive access to custom-made oligonucleotides of the desired sequence. Whereas enzymes synthesize DNA and RNA only in a 5' to 3' direction, chemical oligonucleotide synthesis does not have this limitation, although it is most often carried out in the opposite, 3' to 5' direction. Currently, the process is implemented as solid-phase synthesis using phosphoramidite method and phosphoramidite building blocks derived from protected 2'-deoxynucleosides ( dA, dC, dG, and T), ribonucleosides ( A, C, G, and U), or chemically modified nucleosides, e.g. LNA or BNA. To obtain the desired oligonucleotide, the building blocks are sequentially coupled to the growing oligonucleotide chain in the order required by the sequence of the product ( ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Oligonucleotides
Oligonucleotides are short DNA or RNA molecules, oligomers, that have a wide range of applications in genetic testing, research, and forensics. Commonly made in the laboratory by solid-phase chemical synthesis, these small bits of nucleic acids can be manufactured as single-stranded molecules with any user-specified sequence, and so are vital for artificial gene synthesis, polymerase chain reaction (PCR), DNA sequencing, molecular cloning and as molecular probes. In nature, oligonucleotides are usually found as small RNA molecules that function in the regulation of gene expression (e.g. microRNA), or are degradation intermediates derived from the breakdown of larger nucleic acid molecules. Oligonucleotides are characterized by the sequence of nucleotide residues that make up the entire molecule. The length of the oligonucleotide is usually denoted by " -mer" (from Greek ''meros'', "part"). For example, an oligonucleotide of six nucleotides (nt) is a hexamer, while one of 25 nt ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Modified Oligonucleotides
{{disambiguation ...
Modified may refer to: * ''Modified'' (album), the second full-length album by Save Ferris *Modified racing, or "Modifieds", an American automobile racing genre See also * Modification (other) * Modifier (other) Modifier may refer to: * Grammatical modifier, a word that modifies the meaning of another word or limits its meaning ** Compound modifier, two or more words that modify a noun ** Dangling modifier, a word or phrase that modifies a clause in an a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Tert-Butyloxycarbonyl Protecting Group
The ''tert''-butyloxycarbonyl protecting group or ''tert''-butoxycarbonyl protecting group (BOC group) is a protecting group used in organic synthesis. The BOC group can be added to the amine under aqueous conditions using di-''tert''-butyl dicarbonate in the presence of a base such as sodium carbonate: Protection of the amine can also be accomplished in acetonitrile solution using 4-dimethylaminopyridine (DMAP) as the base. Removal of the BOC in amino acids can be accomplished with strong acids such as trifluoroacetic acid in dichloromethane, or with HCl in methanol. A complication may be the tendency of the ''t''-butyl cation intermediate to alkylate other nucleophiles; scavengers such as anisole or thioanisole may be used. Selective cleavage of the ''N''-Boc group in the presence of other protecting groups is possible when using AlCl3. Sequential treatment with trimethylsilyl iodide then methanol can also be used for Boc deprotection, especially where other deprotec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Fluorenylmethyloxycarbonyl Protecting Group
The fluorenylmethoxycarbonyl protecting group (Fmoc) is a base-labile protecting group used in organic synthesis. Protection & Formation Fmoc carbamate is frequently used as a protecting group for amines, where the Fmoc group can be introduced by reacting the amine with fluorenylmethyloxycarbonyl chloride (Fmoc-Cl), e.g.: : The other common method for introducing the Fmoc group is through 9-fluorenylmethylsuccinimidyl carbonate (Fmoc-OSu), which may itself be obtained by the reaction of Fmoc-Cl with the dicyclohexylammonium salt of ''N''-hydroxysuccinimide. Reacting with 9-fluorenylmethyloxycarbonyl azide (itself made by reacting Fmoc-Cl with sodium azide) in sodium bicarbonate and aqueous dioxane is also a method to install Fmoc group. Because the fluorenyl group is highly fluorescent, certain UV-inactive compounds may be reacted to give the Fmoc derivatives, suitable for analysis by reversed phase HPLC. Analytical uses of Fmoc-Cl that do not use chromatography may be l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Ester
In chemistry, an ester is a compound derived from an oxoacid (organic or inorganic) in which at least one hydroxyl group () is replaced by an alkoxy group (), as in the substitution reaction of a carboxylic acid and an alcohol. Glycerides are fatty acid esters of glycerol; they are important in biology, being one of the main classes of lipids and comprising the bulk of animal fats and vegetable oils. Esters typically have a pleasant smell; those of low molecular weight are commonly used as fragrances and are found in essential oils and pheromones. They perform as high-grade solvents for a broad array of plastics, plasticizers, resins, and lacquers, and are one of the largest classes of synthetic lubricants on the commercial market. Polyesters are important plastics, with monomers linked by ester moieties. Phosphoesters form the backbone of DNA molecules. Nitrate esters, such as nitroglycerin, are known for their explosive properties. '' Nomenclature E ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Amido
In organic chemistry, an amide, also known as an organic amide or a carboxamide, is a compound with the general formula , where R, R', and R″ represent organic groups or hydrogen atoms. The amide group is called a peptide bond when it is part of the main chain of a protein, and an isopeptide bond when it occurs in a side chain, such as in the amino acids asparagine and glutamine. It can be viewed as a derivative of a carboxylic acid () with the hydroxyl group () replaced by an amine group (); or, equivalently, an acyl (alkanoyl) group () joined to an amine group. Common examples of amides are acetamide (), benzamide (), and dimethylformamide (). Amides are qualified as primary, secondary, and tertiary according to whether the amine subgroup has the form , , or , where R and R' are groups other than hydrogen. The core of amides is called the amide group (specifically, carboxamide group). Amides are pervasive in nature and technology. Proteins and important plastics ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Covalent Bond
A covalent bond is a chemical bond that involves the sharing of electrons to form electron pairs between atoms. These electron pairs are known as shared pairs or bonding pairs. The stable balance of attractive and repulsive forces between atoms, when they share electrons, is known as covalent bonding. For many molecules, the sharing of electrons allows each atom to attain the equivalent of a full valence shell, corresponding to a stable electronic configuration. In organic chemistry, covalent bonding is much more common than ionic bonding. Covalent bonding also includes many kinds of interactions, including σ-bonding, π-bonding, metal-to-metal bonding, agostic interactions, bent bonds, three-center two-electron bonds and three-center four-electron bonds. The term ''covalent bond'' dates from 1939. The prefix ''co-'' means ''jointly, associated in action, partnered to a lesser degree, '' etc.; thus a "co-valent bond", in essence, means that the atoms share "valence" ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |