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Reductive Amination
Reductive amination (also known as reductive alkylation) is a form of amination that involves the conversion of a carbonyl group to an amine via an intermediate imine. The carbonyl group is most commonly a ketone or an aldehyde. It is considered the most important way to make amines, and a majority of amines made in the pharmaceutical industry are made this way. Reaction process In this organic reaction, the amine first reacts with the carbonyl group to form a hemiaminal species, which subsequently loses one molecule of water in a reversible manner by alkylimino-de-oxo-bisubstitution, to form the imine. The equilibrium between aldehyde/ketone and imine can be shifted toward imine formation by removal of the formed water through physical or chemical means. This intermediate imine can then be isolated and reduced with a suitable reducing agent (e.g., sodium borohydride). This method is sometimes called indirect reductive amination. In a separate approach, imine formation and redu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amination
Amination is the process by which an amine group is introduced into an organic molecule. This type of reaction is important because organonitrogen compounds are pervasive. Reactions ;Aminase enzymes Enzymes that catalyse this reaction are termed aminases. Amination can occur in a number of ways including reaction with ammonia or another amine such as an alkylation, reductive amination and the Mannich reaction. ;Acid-catatlyzed hydroamination Many alkyl amines are produced industrially by the amination of alcohols using ammonia in the presence of solid acid catalysts. Illustrative is the production of ''tert''-butylamine: :NH3 + CH2=C(CH3)2 → H2NC(CH3)3 ;Ritter reaction The Ritter reaction of isobutene with hydrogen cyanide is not useful in this case because it produces too much waste. In electrophilic amination, the amine as the nucleophile react with another organic compound as the electrophile. This sense of reactivity may be reversed for some electron-deficient amines, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Petasis Reaction
The Petasis reaction (alternatively called the Petasis borono–Mannich (PBM) reaction) is the multi-component reaction of an amine, a carbonyl, and a vinyl- or aryl-boronic acid to form substituted amines. Reported in 1993 by Nicos Petasis as a practical method towards the synthesis of a geometrically pure antifungal agent, naftifine. In the Petasis reaction, the vinyl group of the organoboronic acid serves as the nucleophile. In comparison to other methods of generating allyl amines, the Petasis reaction tolerates a multifunctional scaffold, with a variety of amines and organoboronic acids as potential starting materials. Additionally, the reaction does not require anhydrous or inert conditions. As a mild, selective synthesis, the Petasis reaction is useful in generating α-amino acids, and is utilized in combinatorial chemistry and drug discovery. Reaction scope and synthetic applications The amine is condensed with the carbonyl followed by addition of the boronic acid . ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pyridoxal Phosphate
Pyridoxal phosphate (PLP, pyridoxal 5'-phosphate, P5P), the active form of vitamin B6, is a coenzyme in a variety of enzymatic reactions. The International Union of Biochemistry and Molecular Biology has catalogued more than 140 PLP-dependent activities, corresponding to ~4% of all classified activities. The versatility of PLP arises from its ability to covalently bind the substrate, and then to act as an electrophilic catalyst, thereby stabilizing different types of carbanionic reaction intermediates. Role as a coenzyme PLP acts as a coenzyme in all transamination reactions, and in certain decarboxylation, deamination, and racemization reactions of amino acids. The aldehyde group of PLP forms a Schiff-base linkage (internal aldimine) with the ε-amino group of a specific lysine group of the aminotransferase enzyme. The α-amino group of the amino acid substrate displaces the ε-amino group of the active-site lysine residue in a process known as transaldimination. The resulting ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pyridoxamine Phosphate
Pyridoxamine is one form of vitamin B6, vitamin B6. Chemically it is based on a pyridine ring structure, with hydroxyl, methyl, aminomethyl, and hydroxymethyl substituents. It differs from pyridoxine by the substituent at the 4-position. The hydroxyl at position 3 and aminomethyl group at position 4 of its ring endow pyridoxamine with a variety of chemical properties, including the Scavenger (chemistry), scavenging of free radical species and carbonyl species formed in sugar and lipid degradation and chelation of metal ions that catalyze Amadori rearrangement, Amadori reactions. Research Pyridoxamine can form fairly weak complexes with a number of transition metal ions, with a preference for copper, Cu2+ and Iron (element), Fe3+. The 3'-hydroxyl group of pyridoxamine allows for efficient hydroxyl radical scavenging. Pyridoxamine inhibits the Maillard reaction and can block the formation of advanced glycation endproducts, which are associated with medical complications of diabetes. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transaminase
Transaminases or aminotransferases are enzymes that catalyze a transamination reaction between an amino acid and an α-keto acid. They are important in the synthesis of amino acids, which form proteins. Function and mechanism An amino acid contains an amine (NH2) group. A keto acid contains a keto (=O) group. In transamination, the NH2 group on one molecule is exchanged with the =O group on the other molecule. The amino acid becomes a keto acid, and the keto acid becomes an amino acid. Most transaminases are protein enzymes. However, some transamination activities of the ribosome have been found to be catalyzed by ribozymes (RNA enzymes). Examples being the hammerhead ribozyme, the VS ribozyme and the hairpin ribozyme. Transaminases require the coenzyme pyridoxal phosphate, which is converted into pyridoxamine in the first half-reaction, when an amino acid is converted into a keto acid. Enzyme-bound pyridoxamine in turn reacts with pyruvate, oxaloacetate, or alpha-ketoglut ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amino Acid
Amino acids are organic compounds that contain both amino and carboxylic acid functional groups. Although hundreds of amino acids exist in nature, by far the most important are the alpha-amino acids, which comprise proteins. Only 22 alpha amino acids appear in the genetic code. Amino acids can be classified according to the locations of the core structural functional groups, as Alpha and beta carbon, alpha- , beta- , gamma- or delta- amino acids; other categories relate to Chemical polarity, polarity, ionization, and side chain group type (aliphatic, Open-chain compound, acyclic, aromatic, containing hydroxyl or sulfur, etc.). In the form of proteins, amino acid '' residues'' form the second-largest component (water being the largest) of human muscles and other tissues. Beyond their role as residues in proteins, amino acids participate in a number of processes such as neurotransmitter transport and biosynthesis. It is thought that they played a key role in enabling life ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrogen
Hydrogen is the chemical element with the symbol H and atomic number 1. Hydrogen is the lightest element. At standard conditions hydrogen is a gas of diatomic molecules having the formula . It is colorless, odorless, tasteless, non-toxic, and highly combustible. Hydrogen is the most abundant chemical substance in the universe, constituting roughly 75% of all normal matter.However, most of the universe's mass is not in the form of baryons or chemical elements. See dark matter and dark energy. Stars such as the Sun are mainly composed of hydrogen in the plasma state. Most of the hydrogen on Earth exists in molecular forms such as water and organic compounds. For the most common isotope of hydrogen (symbol 1H) each atom has one proton, one electron, and no neutrons. In the early universe, the formation of protons, the nuclei of hydrogen, occurred during the first second after the Big Bang. The emergence of neutral hydrogen atoms throughout the universe occurred about 370,000 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diisopropylethylamine
''N'',''N''-Diisopropylethylamine, or Hünig's base, is an organic compound and an amine. It is named after the German chemist Siegfried Hünig. It is used in organic chemistry as a base. It is commonly abbreviated as DIPEA, DIEA, or ''i''-Pr2NEt. Structure DIPEA consists of a central nitrogen atom that is bonded to an ethyl group and two isopropyl groups. A lone pair of electrons resides on the nitrogen atom, which can react with electrophiles. However, as the two isopropyl groups and the ethyl group occupy much of the space surrounding the N atom, only small electrophiles such as protons can react with the nitrogen lone pair. Occurrence and preparation DIPEA is commercially available. It is traditionally prepared by the alkylation of diisopropylamine with diethyl sulfate. Pure DIPEA exists as a colorless liquid, although commercial samples can be slightly yellow. If necessary, the compound can be purified by distillation from potassium hydroxide or calcium hydride. Use ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Triethylamine
Triethylamine is the chemical compound with the formula N(CH2CH3)3, commonly abbreviated Et3N. It is also abbreviated TEA, yet this abbreviation must be used carefully to avoid confusion with triethanolamine or tetraethylammonium, for which TEA is also a common abbreviation. It is a colourless volatile liquid with a strong fishy odor reminiscent of ammonia. Like diisopropylethylamine (Hünig's base), triethylamine is commonly employed in organic synthesis, usually as a base. Synthesis and properties Triethylamine is prepared by the alkylation of ammonia with ethanol: :NH3 + 3 C2H5OH → N(C2H5)3 + 3 H2O The pKa of protonated triethylamine is 10.75,David Evans Research Group and it can be used to prepare buffer solutions at that pH. The |
Reductive Amination Acetophenone Ammonia
Reduction, reduced, or reduce may refer to: Science and technology Chemistry * Reduction (chemistry), part of a reduction-oxidation (redox) reaction in which atoms have their oxidation state changed. ** Organic redox reaction, a redox reaction that takes place with organic compounds ** Ore reduction: see smelting Computing and algorithms * Reduction (complexity), a transformation of one problem into another problem * Reduction (recursion theory), given sets A and B of natural numbers, is it possible to effectively convert a method for deciding membership in B into a method for deciding membership in A? * Bit Rate Reduction, an audio compression method * Data reduction, simplifying data in order to facilitate analysis * Graph reduction, an efficient version of non-strict evaluation * L-reduction, a transformation of optimization problems which keeps the approximability features * Partial order reduction, a technique for reducing the size of the state-space to be searched b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acetophenone
Acetophenone is the organic compound with the formula C6H5C(O)CH3. It is the simplest aromatic ketone. This colorless, viscous liquid is a precursor to useful resins and fragrances. Production Acetophenone is formed as a byproduct of the cumene process, the industrial route for the synthesis of phenol and acetone. In the Hock rearrangement of isopropylbenzene hydroperoxide, migration of a methyl group rather than the phenyl group gives acetophenone and methanol as a result of an alternate rearrangement of the intermediate: :C6H5C(CH3)2O2H -> C6H5C(O)CH3 + CH3OH The cumene process is conducted on such a large scale that even the small amount of acetophenone by-product can be recovered in commercially useful quantities. Acetophenone is also generated from ethylbenzene hydroperoxide. Ethylbenzene hydroperoxide is primarily converted to 1-phenylethanol (α-methylbenzyl alcohol) in the process with a small amount of by-product acetophenone. Acetophenone is recovered or hydrogena ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
