Phenyl in the context of "Phenylalanine"

Azo compounds are organic compounds bearing the functional group diazenyl (R−N=N−R′, in which R and R′ can be either aryl or alkyl groups).

IUPAC defines azo compounds as: "Derivatives of diazene (diimide), HN=NH, wherein both hydrogens are substituted by hydrocarbyl groups, e.g. PhN=NPh azobenzene or diphenyldiazene.", where Ph stands for phenyl group. The more stable derivatives contain two aryl groups. The N=N group is called an azo group (from French azote 'nitrogen', from Ancient Greek ἀ- (a-) 'not' and ζωή (zōē) 'life').

Toluene (/ˈtɒl.juiːn/), also known as toluol (/ˈtɒl.ju.ɒl, -ɔːl, -oʊl/), is a substituted aromatic hydrocarbon with the chemical formula C₆H₅CH₃, often abbreviated as PhCH₃, where Ph stands for the phenyl group. It is a colorless, water-insoluble liquid with the odor associated with paint thinners. It is a mono-substituted benzene derivative, consisting of a methyl group (CH₃) attached to a phenyl group by a single bond. As such, its systematic IUPAC name is methylbenzene. Toluene is predominantly used as an industrial feedstock and a solvent.

As the solvent in some types of paint thinner, permanent markers, contact cement and certain types of glue, toluene is sometimes used as a recreational inhalant and has the potential of causing severe neurological harm.

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. "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.

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

Methyl benzoate is an organic compound. It is an ester with the chemical formula C₆H₅COOCH₃, sometimes abbreviated as PhCO₂Me, where Ph and Me are phenyl and methyl, respectively. Its structure is C₆H₅−C(=O)−O−CH₃. It is a colorless liquid that is poorly soluble in water, but miscible with organic solvents. Methyl benzoate has a pleasant smell, strongly reminiscent of the fruit of the feijoa tree, and it is used in perfumery. It also finds use as a solvent and as a pesticide used to attract insects such as orchid bees.

Anisole, or methoxybenzene, is an organic compound with the formula CH₃OC₆H₅. It is a colorless liquid with a smell reminiscent of anise seed, and in fact many of its derivatives are found in natural and artificial fragrances. The compound is mainly made synthetically and is a precursor to other synthetic compounds. Structurally, it is an ether (−O−) with a methyl (−CH₃) and phenyl (−C₆H₅) group attached. Anisole is a standard reagent of both practical and pedagogical value.

Anthocyanidins are common plant pigments, the aglycones of anthocyanins. They are based on the flavylium cation, an oxonium ion, with various groups substituted for its hydrogen atoms. They generally change color from red through purple, blue, and bluish green as a function of pH.

Anthocyanidins are an important subclass of the polymethine dyes and flavonoids. The flavylium cation is a chromenylium cation with a phenyl group substituted in position 2; and chromenylium (also called benzopyrylium) is a bicyclic version of pyrylium. The positive charge can move around the molecule.

Azobenzene is a photoswitchable chemical compound composed of two phenyl rings linked by a N=N double bond. It is the simplest example of an aryl azo compound. The term "azobenzene" or simply "azo" is often used to refer to a wide class of similar compounds. These azo compounds are considered as derivatives of diazene (diimide), and are sometimes referred to as "diazenes". The diazenes absorb light strongly and are common dyes. Different classes of azo dyes exist, most notably the ones substituted with heteroaryl rings.