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Benzyl
In organic chemistry, benzyl is the substituent or molecular fragment possessing the structure . Benzyl features a benzene ring () attached to a methylene group () group. Nomenclature In IUPAC nomenclature, the prefix benzyl refers to a substituent, for example benzyl chloride or benzyl benzoate. Benzyl is not to be confused with phenyl with the formula . The term benzylic is used to describe the position of the first carbon bonded to a benzene or other aromatic ring. For example, is referred to as a "benzylic" carbocation. The benzyl free radical has the formula . The benzyl cation or phenylcarbenium ion is the carbocation with formula ; the benzyl anion or phenylmethanide ion is the carbanion with the formula . None of these species can be formed in significant amounts in the solution phase under normal conditions, but they are useful referents for discussion of reaction mechanisms and may exist as reactive intermediates. Abbreviations The abbreviation "Bn" denotes be ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Benzyl Alcohol
Benzyl alcohol is an aromatic alcohol with the formula C6H5CH2OH. The benzyl group is often abbreviated "Bn" (not to be confused with "Bz" which is used for benzoyl), thus benzyl alcohol is denoted as BnOH. Benzyl alcohol is a colorless liquid with a mild pleasant aromatic odor. It is a useful solvent due to its polarity, low toxicity, and low vapor pressure. Benzyl alcohol has moderate solubility in water (4 g/100 mL) and is miscible in alcohols and diethyl ether. The anion produced by deprotonation of the alcohol group is known as benzylate or benzyloxide. Natural occurrences Benzyl alcohol is produced naturally by many plants and is commonly found in fruits and teas. It is also found in a variety of essential oils including jasmine, hyacinth and ylang-ylang. It is also found in castoreum from the castor sacs of beavers. Benzyl esters also occur naturally. Preparation Benzyl alcohol is produced industrially from toluene via benzyl chloride, which ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Benzyl Benzoate
Benzyl benzoate is an organic compound which is used as a medication and insect repellent. As a medication it is used to treat scabies and lice. For scabies either permethrin or malathion is typically preferred. It is applied to the skin as a lotion. Typically two to three applications are needed. It is also present in Balsam of Peru, Tolu balsam, and in a number of flowers. Side effects may include irritation of the skin. It is not recommended in children. It is also used in other animals; however, it is considered toxic to cats. How it works is unclear. Benzyl benzoate was first studied medically in 1918. It is on the World Health Organization's List of Essential Medicines. Benzyl benzoate is sold under the brand name Scabanca among others and is available as a generic medication. It is not available for medical use in the United States. Uses Medical Benzyl benzoate is an effective and inexpensive topical treatment for human scabies. It has vasodilating and spas ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Benzyl Chloride
Benzyl chloride, or α-chlorotoluene, is an organic compound with the formula C6H5CH2Cl. This colorless liquid is a reactive organochlorine compound that is a widely used chemical building block. Preparation Benzyl chloride is prepared industrially by the gas-phase photochemical reaction of toluene with chlorine: :C6H5CH3 + Cl2 → C6H5CH2Cl + HCl In this way, approximately 100,000 tonnes are produced annually. The reaction proceeds by the free radical process, involving the intermediacy of free chlorine atoms. Side products of the reaction include benzal chloride and benzotrichloride. Other methods of production exist, such as the Blanc chloromethylation of benzene. Benzyl chloride was first prepared from treatment of benzyl alcohol with hydrochloric acid. Uses and reactions Industrially, benzyl chloride is the Precursor (chemistry), precursor to benzyl esters, which are used as plasticizers, flavorants, and perfumes. Phenylacetic acid, a precursor to pharmaceuticals, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Benzyl Group V
In organic chemistry, benzyl is the substituent or molecular fragment possessing the structure . Benzyl features a benzene ring () attached to a methylene group () group. Nomenclature In IUPAC nomenclature, the prefix benzyl refers to a substituent, for example benzyl chloride or benzyl benzoate. Benzyl is not to be confused with phenyl with the formula . The term benzylic is used to describe the position of the first carbon bonded to a benzene or other aromatic ring. For example, is referred to as a "benzylic" carbocation. The benzyl free radical has the formula . The benzyl cation or phenylcarbenium ion is the carbocation with formula ; the benzyl anion or phenylmethanide ion is the carbanion with the formula . None of these species can be formed in significant amounts in the solution phase under normal conditions, but they are useful referents for discussion of reaction mechanisms and may exist as reactive intermediates. Abbreviations The abbreviation "Bn" denotes benzyl. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Allylic
In organic chemistry, an allyl group is a substituent with the structural formula , where R is the rest of the molecule. It consists of a methylene bridge () attached to a vinyl group (). The name is derived from the scientific name for garlic, . In 1844, Theodor Wertheim isolated an allyl derivative from garlic oil and named it "". The term allyl applies to many compounds related to , some of which are of practical or of everyday importance, for example, allyl chloride. Allylation is any chemical reaction that adds an allyl group to a substrate. Nomenclature A site adjacent to the unsaturated carbon atom is called the allylic position or allylic site. A group attached at this site is sometimes described as allylic. Thus, "has an allylic hydroxyl group". Allylic C−H bonds are about 15% weaker than the C−H bonds in ordinary sp3 carbon centers and are thus more reactive. Benzylic and allylic are related in terms of structure, bond strength, and reactivity. Other ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Benzoyl
In organic chemistry, benzoyl (, ) is the functional group with the formula C6H5CO-. It can be viewed as benzaldehyde missing one hydrogen. The term "benzoyl" should not be confused with benzyl, which has the formula C6H5CH2. The benzoyl group is given the symbol "Bz". Benzyl is commonly abbreviated "Bn". Sources Benzoyl chloride is a favored source of benzoyl groups, being used to prepare benzoyl ketones, benzamides (benzoyl amides), and benzoate esters. The source of many naturally occurring benzoyl compounds is the thioester benzoyl-CoA. Irradiation of benzil generates benzoyl radicals, which have the formula PhCO. Benzoyl compounds Many ketones contain the benzoyl group. They have the formula C6H5CO–R, an important example being benzophenone. Benzoyl esters and amides are common in organic chemistry. The esters are used as a protecting groups in organic synthesis, which can be easily removed by hydrolysis in dilute basic BASIC (Beginners' All-purpose Symbolic I ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carbanion
In organic chemistry, a carbanion is an anion in which carbon is trivalent (forms three bonds) and bears a formal negative charge (in at least one significant resonance form). Formally, a carbanion is the conjugate base of a carbon acid: :R3CH\, + \ddot^- -> \mathbf + HB where B stands for the base. The carbanions formed from deprotonation of alkanes (at an sp3 carbon), alkenes (at an sp2 carbon), arenes (at an sp2 carbon), and alkynes (at an sp carbon) are known as alkyl, alkenyl (vinyl), aryl, and alkynyl ( acetylide) anions, respectively. Carbanions have a concentration of electron density at the negatively charged carbon, which, in most cases, reacts efficiently with a variety of electrophiles of varying strengths, including carbonyl groups, imines/ iminium salts, halogenating reagents (e.g., ''N''-bromosuccinimide and diiodine), and proton donors. A carbanion is one of several reactive intermediates in organic chemistry. In organic synthesis, organolithium reagents an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wohl–Ziegler Bromination
The Wohl–Ziegler reaction is a chemical reaction that involves the allylic or benzylic bromination of hydrocarbons using an ''N''-bromosuccinimide and a radical initiator. : Best yields are achieved with ''N''-bromosuccinimide in carbon tetrachloride solvent. Several reviews have been published. In a typical setup, a stoichiometric amount of ''N''-bromosuccinimide solution and a small quantity of initiator are added to a solution of the substrate in CCl4, and the reaction mixture is stirred and heated to the boiling point. Initiation of the reaction is indicated by more vigorous boiling; sometimes the heat source may need to be removed. Once all ''N''-bromosuccinimide (which is denser than the solvent) has been converted to succinimide Succinimide is an organic compound with the formula (CH2)2(CO)2NH. This white solid is used in a variety of organic syntheses, as well as in some industrial silver plating processes. The compound is classified as a cyclic imide. It may be prep ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trityl
Triphenylmethane, or triphenyl methane, is the hydrocarbon with the formula (C6H5)3CH. This colorless solid is soluble in nonpolar organic solvents and not in water. Triphenylmethane is the basic skeleton of many synthetic dyes called triarylmethane dyes, many of them are pH indicators, and some display fluorescence. A trityl group in organic chemistry is a triphenylmethyl group Ph3C, e.g. triphenylmethyl chloride (trityl chloride) and the triphenylmethyl radical (trityl radical). Preparation Triphenylmethane was first synthesized in 1872 by the German chemist August Kekulé and his Belgian student Antoine Paul Nicolas Franchimont (1844–1919) by heating diphenylmercury (Hg(C6H5)2, ''Quecksilberdiphenyl'') with benzal chloride (C6H5CHCl2, ''Benzylenchlorid''). Triphenylmethane can be synthesized by Friedel–Crafts reaction from benzene and chloroform with aluminium chloride catalyst: :3 C6H6 + CHCl3 → Ph3CH + 3 HCl Alternatively, benzene may react with carbon tetrach ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Benzhydryl Compounds
The benzhydryl compounds are a group of organic compounds whose parent structures include diphenylmethane (which is two benzene rings connected by a single methane), with any number of attached substituents, including bridges. This group typically excludes compounds in which either benzene is fused to another ring (bicyclic, tricyclic, polycyclic) or includes a heteroatom, or where the methane connects to three or four benzenes. The benzhydryl ''radical'' can be abbreviated or Bzh. Carboaromatic Alcohols *''Acyclic:'' pridinol *''Pyrolidino:'' diphenylprolinol *''2-Piperidine:'' pipradrol *''4-Piperidine:'' terfenadine, fexofenadine *''Benzilic ester:'' QNB, JB-336, JB-318, benactyzine Alkenes *''Tricycle:'' amitriptyline, melitracen, cyclobenzaprine, tianeptine, amineptine, clopenthixol, chlorprothixene, flupentixol, thiothixene, zuclopenthixol *''Tricyclic and piperidine:'' pimethixene, cyproheptadine *''Acyclic:'' gilutensin Alkyl(amine)s *''Acyclic:'' (3 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bond Dissociation Energy
The bond-dissociation energy (BDE, ''D''0, or ''DH°'') is one measure of the strength of a chemical bond . It can be defined as the standard enthalpy change when is cleaved by homolysis to give fragments A and B, which are usually radical species. The enthalpy change is temperature-dependent, and the bond-dissociation energy is often defined to be the enthalpy change of the homolysis at 0 K (absolute zero), although the enthalpy change at 298 K (standard conditions) is also a frequently encountered parameter. As a typical example, the bond-dissociation energy for one of the C−H bonds in ethane () is defined as the standard enthalpy change of the process : , : ''DH''°298() = Δ''H°'' = 101.1(4) kcal/mol = 423.0 ± 1.7 kJ/mol = 4.40(2) eV (per bond). To convert a molar BDE to the energy needed to dissociate the bond ''per molecule'', the conversion factor 23.060 kcal/mol (96.485 kJ/mol) for each eV can be used. A variety of experim ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carbocation
A carbocation is an ion with a positively charged carbon atom. Among the simplest examples are the methenium , methanium and vinyl cations. Occasionally, carbocations that bear more than one positively charged carbon atom are also encountered (e.g., ethylene dication ). Until the early 1970s, all carbocations were called ''carbonium ions''. In the present-day definition given by the IUPAC, a carbocation is any even-electron cation with significant partial positive charge on a carbon atom. They are further classified in two main categories according to the coordination number of the charged carbon: three in the carbenium ions and five in the carbonium ions. This nomenclature was proposed by G. A. Olah. Carbonium ions, as originally defined by Olah, are characterized by a three-center two-electron delocalized bonding scheme and are essentially synonymous with so-called ' non-classical carbocations', which are carbocations that contain bridging C–C or C–H σ-bonds. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
