Aryl group

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A phenyl group is the simplest aryl group, here bonded to an "R" group. Phenyl-group.svg
A phenyl group is the simplest aryl group, here bonded to an "R" group.

In organic chemistry, an aryl is any functional group or substituent derived from an aromatic ring, usually an aromatic hydrocarbon, such as phenyl and naphthyl. [1] "Aryl" is used for the sake of abbreviation or generalization, and "Ar" is used as a placeholder for the aryl group in chemical structure diagrams, analogous to “R” used for any organic substituent. “Ar” is not to be confused with the elemental symbol for argon.

Contents

A simple aryl group is phenyl (C6H5), a group derived from benzene. Examples of other aryl groups consist of:

Arylation is the process in which an aryl group is attached to a substituent. It is typically achieved by cross-coupling reactions.

Nomenclature

The most basic aryl group is phenyl, which is made up of a benzene ring with one of its hydrogen atom replaced by some substituent, and has the molecular formula C6H5. Note that a phenyl group is not the same as a benzyl group, the latter consisting of a phenyl group attached to a methyl group and a molecular formula of C6H5CH2. [2]

Phenol (or hydroxybenzene) Phenol-2.svg
Phenol (or hydroxybenzene)

To name compounds containing phenyl groups, the phenyl group can be taken to be the parent hydrocarbon and be represented by the suffix "–benzene". Alternatively, the phenyl group could be treated as the substituent, being described within the name as "phenyl". This is usually done when the group attached to the phenyl group consists of six or more carbon atoms. [3]

As an example, consider a hydroxyl group connected to a phenyl group. In this case, if the phenyl group were taken to be the parent hydrocarbon, the compound would be named hydroxybenzene. Alternatively, and more commonly, the hydroxyl group could be taken as the parent group and the phenyl group treated as the substituent, resulting in the more familiar name phenol. [4]

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Aromatic compounds or arenes 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:

<span class="mw-page-title-main">Ether</span> Organic compounds made of alkyl/aryl groups bound to oxygen (R–O–R)

In organic chemistry, ethers are a class of compounds that contain an ether group—an oxygen atom connected to two alkyl or aryl groups. They have the general formula R−O−R′, where R and R′ represent the alkyl or aryl groups. Ethers can again be classified into two varieties: if the alkyl or aryl groups are the same on both sides of the oxygen atom, then it is a simple or symmetrical ether, whereas if they are different, the ethers are called mixed or unsymmetrical ethers. A typical example of the first group is the solvent and anaesthetic diethyl ether, commonly referred to simply as "ether". Ethers are common in organic chemistry and even more prevalent in biochemistry, as they are common linkages in carbohydrates and lignin.

<span class="mw-page-title-main">Functional group</span> Set of atoms in a molecule which augment its chemical and/or physical properties

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<span class="mw-page-title-main">Phenyl group</span> Cyclic chemical group (–C₆H₅)

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.

<span class="mw-page-title-main">Cycloalkane</span> Saturated alicyclic hydrocarbon

In organic chemistry, the cycloalkanes are the monocyclic saturated hydrocarbons. In other words, a cycloalkane consists only of hydrogen and carbon atoms arranged in a structure containing a single ring, and all of the carbon-carbon bonds are single. The larger cycloalkanes, with more than 20 carbon atoms are typically called cycloparaffins. All cycloalkanes are isomers of alkenes.

In organic chemistry, an alkyl group is an alkane missing one hydrogen. The term alkyl is intentionally unspecific to include many possible substitutions. An acyclic alkyl has the general formula of −CnH2n+1. A cycloalkyl group is derived from a cycloalkane by removal of a hydrogen atom from a ring and has the general formula −CnH2n−1. Typically an alkyl is a part of a larger molecule. In structural formulae, the symbol R is used to designate a generic (unspecified) alkyl group. The smallest alkyl group is methyl, with the formula −CH3.

<span class="mw-page-title-main">Aniline</span> Organic compound (C₆H₅NH₂); simplest aromatic amine

Aniline is an organic compound with the formula C6H5NH2. Consisting of a phenyl group attached to an amino group, aniline is the simplest aromatic amine. It is an industrially significant commodity chemical, as well as a versatile starting material for fine chemical synthesis. Its main use is in the manufacture of precursors to polyurethane, dyes, and other industrial chemicals. Like most volatile amines, it has the odor of rotten fish. It ignites readily, burning with a smoky flame characteristic of aromatic compounds. It is toxic to humans.

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<span class="mw-page-title-main">Skeletal formula</span> Representation method in chemistry

The skeletal formula, line-angle formula, or shorthand formula of an organic compound is a type of molecular structural formula that serves as a shorthand representation of a molecule's bonding and some details of its molecular geometry. A skeletal formula shows the skeletal structure or skeleton of a molecule, which is composed of the skeletal atoms that make up the molecule. It is represented in two dimensions, as on a piece of paper. It employs certain conventions to represent carbon and hydrogen atoms, which are the most common in organic chemistry.

In organic chemistry, a substituent is one or a group of atoms that replaces atoms, thereby becoming a moiety in the resultant (new) molecule.

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Arene substitution patterns are part of organic chemistry IUPAC nomenclature and pinpoint the position of substituents other than hydrogen in relation to each other on an aromatic hydrocarbon.

<span class="mw-page-title-main">Cyclic compound</span> Molecule with a ring of bonded atoms

A cyclic compound is a term for a compound in the field of chemistry in which one or more series of atoms in the compound is connected to form a ring. Rings may vary in size from three to many atoms, and include examples where all the atoms are carbon, none of the atoms are carbon, or where both carbon and non-carbon atoms are present. Depending on the ring size, the bond order of the individual links between ring atoms, and their arrangements within the rings, carbocyclic and heterocyclic compounds may be aromatic or non-aromatic; in the latter case, they may vary from being fully saturated to having varying numbers of multiple bonds between the ring atoms. Because of the tremendous diversity allowed, in combination, by the valences of common atoms and their ability to form rings, the number of possible cyclic structures, even of small size numbers in the many billions.

Pyrylium is a cation with formula C5H5O+, consisting of a six-membered ring of five carbon atoms, each with one hydrogen atom, and one positively charged oxygen atom. The bonds in the ring are conjugated as in benzene, giving it an aromatic character. In particular, because of the positive charge, the oxygen atom is trivalent. Pyrilium is a mono-cyclic and heterocyclic compound, one of the oxonium ions.

<span class="mw-page-title-main">Phenyl azide</span> Chemical compound

Phenyl azide is an organic compound with the formula C6H5N3. It is one of the prototypical organic azides. It is a pale yellow oily liquid with a pungent odor. The structure consists of a linear azide substituent bound to a phenyl group. The C−N=N angle is approximately 120°. It was discovered in 1864 by Peter Griess by the reaction of ammonia and phenyldiazonium.

<span class="mw-page-title-main">Diphenylmethane</span> Chemical compound

Diphenylmethane is an organic compound with the formula (C6H5)2CH2 (often abbreviated CH
2
Ph
2
). The compound consists of methane wherein two hydrogen atoms are replaced by two phenyl groups. It is a white solid.

<span class="mw-page-title-main">Phenacyl group</span> Functional group

In organic chemistry, a phenacyl group is an aromatic substituent that consists of a phenyl group attached to an acyl group. A molecule containing a phenacyl group has the formula RCH2(CO)C6H5 and the structure shown to the right. Here, R denotes the remainder of the molecule; for instance, if R is Br, then the compound could be called "phenacyl bromide". Note however that in the standard IUPAC nomenclature this compound would instead be called "2-bromo-1-phenylethanone".

<span class="mw-page-title-main">Parent structure</span> Chemical structure from which derivatives can be visualized

In chemistry, a parent structure is the structure of an unadorned ion or molecule from which derivatives can be visualized. Parent structures underpin systematic nomenclature and facilitate classification. Fundamental parent structures have one or no functional groups and often have various types of symmetry. Benzene is a chemical itself consisting of a hexagonal ring of carbon atoms with a hydrogen atom attached to each, and is the parent of many derivatives that have substituent atoms or groups replacing one or more of the hydrogens. Some parents are rare or nonexistent themselves, as in the case of porphine, though many simple and complex derivatives are known.

<span class="mw-page-title-main">Phenol ether</span> O-alkyl derivative of phenol

In chemistry, a phenol ether (or aromatic ether) is an organic compound derived from phenol (C6H5OH), where the hydroxyl (-OH) group is substituted with an alkoxy (-OR) group. Usually phenol ethers are synthesized through the condensation of phenol and an organic alcohol; however, other known reactions regarding the synthesis of ethers can be applied to phenol ethers as well. Anisole (C6H5OCH3) is the simplest phenol ether, and is a versatile precursor for perfumes and pharmaceuticals. Vanillin and ethylvanillin are phenol ether derivatives commonly utilized in vanilla flavorings and fragrances, while diphenyl ether is commonly used as a synthetic geranium fragrance. Phenol ethers are part of the chemical structure of a variety of medications, including quinine, an antimalarial drug, and dextromethorphan, an over-the-counter cough suppressant.

References

  1. IUPAC , Compendium of Chemical Terminology , 2nd ed. (the "Gold Book") (1997). Online corrected version: (2006) " aryl groups ". doi : 10.1351/goldbook.A00464
  2. Carey, Francis; Sundberg, Richard (2008). Advanced Organic Chemistry, Part A: Structure and Mechanisms (5th ed.). Springer.
  3. IUPAC, Commission on Nomenclature of Organic Chemistry (1993). A Guide to IUPAC Nomenclature of Organic Compounds (Recommendations 1993). Blackwell Scientific Publications. Archived from the original on 2014-02-08. Retrieved 2017-10-26 via acdlabs.com.
  4. Brown, William Henry (2018). Organic chemistry. Brent L. Iverson, Eric V. Anslyn, Christopher S. Foote (8th ed.). Boston, MA. ISBN   978-1-305-58035-0. OCLC   974377227.{{cite book}}: CS1 maint: location missing publisher (link)
  5. Bock KW, Köhle C (2006). "Ah receptor: dioxin-mediated toxic responses as hints to deregulated physiologic functions". Biochem. Pharmacol. 72 (4): 393–404. doi:10.1016/j.bcp.2006.01.017. PMID   16545780.