Aromatic compounds usually refers to organic compounds "with a chemistry typified by benzene" and "cyclically conjugated " The word "aromatic" originates from the past grouping of molecules based on odor, before their general chemical properties were understood. The current definition of aromatic compounds does not have any relation to their odor. Aromatic compounds are now defined as cyclic compounds satisfying Hückel's Rule. Aromatic compounds have the following general properties:
In organic chemistry, a functional group is a substituent or moiety in a molecule that causes the molecule's characteristic chemical reactions. The same functional group will undergo the same or similar chemical reactions regardless of the rest of the molecule's composition. This enables systematic prediction of chemical reactions and behavior of chemical compounds and the design of chemical synthesis. The reactivity of a functional group can be modified by other functional groups nearby. Functional group interconversion can be used in retrosynthetic analysis to plan organic synthesis.
In organic chemistry, the phenyl group, or phenyl ring, is a cyclic group of atoms with the formula C6H5, and is often represented by the symbol Ph. The phenyl group is closely related to benzene and can be viewed as a benzene ring, minus a hydrogen, which may be replaced by some other element or compound to serve as a functional group. A phenyl group has six carbon atoms bonded together in a hexagonal planar ring, five of which are bonded to individual hydrogen atoms, with the remaining carbon bonded to a substituent. Phenyl groups are commonplace in organic chemistry. Although often depicted with alternating double and single bonds, the phenyl group is chemically aromatic and has equal bond lengths between carbon atoms in the ring.
Carl Graebe was a German industrial and academic chemist from Frankfurt am Main who held professorships in his field at Leipzig, Königsberg, and Geneva. He is known for the first synthesis of the economically important dye, alizarin, with Liebermann, and for contributing to the fundamental nomenclature of organic chemistry.
In chemical nomenclature, the IUPAC nomenclature of organic chemistry is a method of naming organic chemical compounds as recommended by the International Union of Pure and Applied Chemistry (IUPAC). It is published in the Nomenclature of Organic Chemistry. Ideally, every possible organic compound should have a name from which an unambiguous structural formula can be created. There is also an IUPAC nomenclature of inorganic chemistry.
In organic chemistry, nitration is a general class of chemical processes for the introduction of a nitro group into an organic compound. The term also is applied incorrectly to the different process of forming nitrate esters between alcohols and nitric acid. The difference between the resulting molecular structures of nitro compounds and nitrates is that the nitrogen atom in nitro compounds is directly bonded to a non-oxygen atom, whereas in nitrate esters, the nitrogen is bonded to an oxygen atom that in turn usually is bonded to a carbon atom.
In electrophilic aromatic substitution reactions, existing substituent groups on the aromatic ring influence the overall reaction rate or have a directing effect on positional isomer of the products that are formed. An electron donating group (EDG) or electron releasing group is an atom or functional group that donates some of its electron density into a conjugated π system via resonance (mesomerism) or inductive effects —called +M or +I effects, respectively—thus making the π system more nucleophilic. As a result of these electronic effects, an aromatic ring to which such a group is attached is more likely to participate in electrophilic substitution reaction. EDGs are therefore often known as activating groups, though steric effects can interfere with the reaction.
o-Xylene (ortho-xylene) is an aromatic hydrocarbon with the formula C6H4(CH3)2, with two methyl substituents bonded to adjacent carbon atoms of a benzene ring (the ortho configuration). It is a constitutional isomer of m-xylene and p-xylene, the mixture being called xylene or xylenes. o-Xylene is a colourless slightly oily flammable liquid.
m-Xylene (meta-xylene) is an aromatic hydrocarbon. It is one of the three isomers of dimethylbenzene known collectively as xylenes. The m- stands for meta-, indicating that the two methyl groups in m-xylene occupy positions 1 and 3 on a benzene ring. It is in the positions of the two methyl groups, their arene substitution pattern, that it differs from the other isomers, o-xylene and p-xylene. All have the same chemical formula C6H4(CH3)2. All xylene isomers are colorless and highly flammable.
In chemistry, azoxy compounds are a group of organic compounds sharing a common functional group with the general structure R−N=N+(−O−)−R. They are considered N-oxides of azo compounds. Azoxy compounds are 1,3-dipoles and cycloadd to double bonds. Most azoxy-containing compounds have aryl substituents.
In organic chemistry, the Hammett equation describes a linear free-energy relationship relating reaction rates and equilibrium constants for many reactions involving benzoic acid derivatives with meta- and para-substituents to each other with just two parameters: a substituent constant and a reaction constant. This equation was developed and published by Louis Plack Hammett in 1937 as a follow-up to qualitative observations in his 1935 publication.
Divinylbenzene (DVB) is an organic compound with the chemical formula C6H4(CH=CH2)2 and structure H2C=CH−C6H4−HC=CH2. It is related to styrene by the addition of a second vinyl group. It is a colorless liquid manufactured by the thermal dehydrogenation of isomeric diethylbenzenes. Under synthesis conditions, o-divinylbenzene converts to naphthalene and thus is not a component of the usual mixtures of DVB.
In chemistry, meta is a prefix, used for systematic names in IUPAC nomenclature. It has several meanings.
In organic chemistry, the vicarious nucleophilic substitution is a special type of nucleophilic aromatic substitution in which a nucleophile replaces a hydrogen atom on the aromatic ring and not leaving groups such as halogen substituents which are ordinarily encountered in SNAr. This reaction type was reviewed in 1987 by Polish chemists Mieczysław Mąkosza and Jerzy Winiarski.
In organic chemistry, tolyl groups are functional groups related to toluene. They have the general formula CH3C6H4−R, the change of the relative position of the methyl and the R substituent on the aromatic ring can generate three possible structural isomers 1,2 (ortho), 1,3 (meta), and 1,4 (para). Tolyl groups are aryl groups which are commonly found in the structure of diverse chemical compounds. They are considered nonpolar and hydrophobic groups.
The Birch reduction is an organic reaction that is used to convert arenes to 1,4-cyclohexadienes. The reaction is named after the Australian chemist Arthur Birch and involves the organic reduction of aromatic rings in an amine solvent with an alkali metal and a proton source. Unlike catalytic hydrogenation, Birch reduction does not reduce the aromatic ring all the way to a cyclohexane.
Electrophilic aromatic substitution is an organic reaction in which an atom that is attached to an aromatic system is replaced by an electrophile. Some of the most important electrophilic aromatic substitutions are aromatic nitration, aromatic halogenation, aromatic sulfonation, alkylation and acylation Friedel–Crafts reaction.
In chemical nomenclature, a descriptor is a notational prefix placed before the systematic substance name, which describes the configuration or the stereochemistry of the molecule. Some listed descriptors are only of historical interest and should not be used in publications anymore as they do not correspond with the modern recommendations of the IUPAC. Stereodescriptors are often used in combination with locants to clearly identify a chemical structure unambiguously.
In organic chemistry, a diethynylbenzene dianion is an anion consisting of two ethynyl anions as substituents on a benzene ring. With the chemical formula C
6H
4C2−
4, three positional isomers are possible, differing in the relative positions of the two substituents around the ring:
Ortho effect is a organic chemistry phenomenon where the presence of an chemical group at the at ortho position or the 1 and 2 position of a phenyl ring, relative to the carboxylic compound changes the chemical properties of the compound. This is caused by steric effects and bonding interactions along with polar effects caused by the various substituents which are in a given molecule, resulting in changes in its chemical and physical properties. The ortho effect is associated with substituted benzene compounds.
