The alpha carbon in organic chemistry refers to the first carbon after the carbon that attaches to the functional group (the carbon is attached at the first, or alpha, position). Organic chemistry is a discipline within Chemistry which involves the scientific study of the structure properties composition reactions, and preparation In Organic chemistry, functional groups are specific groups of Atoms within Molecules that are responsible for the characteristic Chemical reactions By extension, the second carbon is the beta carbon, and so on. This nomenclature can also be applied to the hydrogen atoms attached to the carbons. A hydrogen attached to an alpha carbon is called an "alpha-hydrogen" (α-hydrogen), a hydrogen on the beta-carbon is a beta-hydrogen, and so on.
This naming standard is sometimes considered to be not in compliance with IUPAC nomenclature (which encourages that carbons be identified by number, not by Greek letter); but it nonetheless remains very popular, particularly because it is useful in identifying the relative location of carbons to other functional groups (often a carbonyl). IUPAC Nomenclature is a system of naming Chemical compounds and of describing the science of Chemistry in general In Organic chemistry, a carbonyl group is a Functional group composed of a Carbon Atom double-bonded to an Oxygen
α-carbon is also a term that applies to proteins and amino acids. Proteins are large Organic compounds made of Amino acids arranged in a linear chain and joined together by Peptide bonds between the Carboxyl In Chemistry, an amino acid is a Molecule containing both Amine and Carboxyl Functional groups In Biochemistry, this It is the backbone carbon next to the carbonyl carbon. Therefore, reading along the backbone of a typical protein would give a sequence of carbonyl C, α-C, N, carbonyl C, α-C, N, and so on (when reading in the C to N direction). The α-carbon is where the different substituents attach to each different amino acid. That is, the groups hanging off the chain at the α-carbon are what give amino acids their diversity. These groups give the α-carbon its stereogenic properties for every amino acid except for glycine. A stereocenter, or stereogenic centre, is any Atom in a Molecule bearing groups such that an interchanging of any two groups leads to a Stereoisomer Glycine (abbreviated as Gly or G) is the Organic compound with the formula NH2CH2COOH Therefore, the α-carbon is a stereocenter for every amino acid except glycine. A stereocenter, or stereogenic centre, is any Atom in a Molecule bearing groups such that an interchanging of any two groups leads to a Stereoisomer
The α-carbon of an amino acid is significant in protein folding. Protein folding is the physical process by which a Polypeptide folds into its characteristic and functional three-dimensional structure. When describing a protein (which is a chain of amino acids), one often approximates the location of each amino acid as the location of its α-carbon. In general, α-carbons of adjacent amino acids in a protein are about 3. 8 ångströms (380 picometers) apart. An ångström or angstrom (symbol Å) (ˈɔːŋstrəm Swedish: ˈɔ̀ŋstrœm is an internationally recognized non- SI unit of length equal A picometre ( American spelling: picometer, symbol pm) is a unit of Length in the Metric system, equal to one trillionth
The α-carbon is important for enol and enolate based carbonyl chemistry as well. Enols (also known as alkenols) are Alkenes with a Hydroxyl group affixed to one of the carbon atoms composing the Double bond. In Organic chemistry, a carbonyl group is a Functional group composed of a Carbon Atom double-bonded to an Oxygen Chemical transformations effected by the conversion to either an enolate or enol generally lead to the α-carbon acting as a nucleophile becoming, for example, alkyated in the presence of primary haloalkane. The haloalkanes (also known as halogenoalkanes or alkyl halides) are a group of Chemical compounds consisting of Alkanes such as Methane An exception is in reaction with silyl- chlorides, -bromides, and -iodides, where the oxygen acts as the nucleophile to produce silyl enol ether. Silyl enol ethers in Organic chemistry are a class of Organic compounds sharing a common Functional group composed of an Enolate bonded through
In ketones (a type of carbonyl) with acidic alpha hydrogen atoms on either side of the carbonyl carbon, selectivity of deprotonation may be achieved under select conditions. A ketone (pronounced as key tone) is either the Functional group characterized by a Carbonyl group (O=C linked to two other Carbon atoms or Deprotonation is a Chemistry term that refers to the removal of a Proton ( Hydrogen Cation H+ from a Molecule, forming At low temperatures (-78°C, i. e. dry ice bath), in aprotic solvents, and with bulky non-equilibrating bases (e. g. LDA) the "kinetic" proton may be removed. Lithium diisopropylamide is the Chemical compound with the formula 2NLi The "kinetic" proton is the one which is sterically most accessible. Under thermodynamic conditions (warmer temperatures, weak base, and protic solvent) equilibrium is established between the ketone and the two possible enolates, the enolate favoured is termed the "thermodynamic" enolate and is favoured because of its lower energy level than the other possible enolate. Thermodynamic reaction control or kinetic reaction control in a Chemical reaction can decide the composition in a reaction product when competing reactions lead to Thus, by choosing the "correct" conditions to generate an enolate one can increase the yield of the desired product and minimize the formation of the undesired product.
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